January 2015 

NASA/TP2015-218674 

NESC-RP-13-00884 

 

Spin Forming Aluminum Crew Module (CM) 

Metallic Aft Pressure Vessel Bulkhead 

(APVBH) – Phase II 

Eric K. Hoffman and Marcia S. Domack 

Langley Research Center, Hampton, Virginia 

Pablo D. Torres and Preston B. McGill 

Marshall Space Flight Center, Huntsville, Alabama 

Wesley A. Tayon 

Langley Research Center, Hampton, Virginia 

Jay E. Bennett 

Johnson Space Center, Houston, Texas 

Joseph T. Murphy 

Lockheed Martin Space Systems Company, New Orleans, Louisiana 
NASA STI Program . . . in Profile

Since its founding, NASA has been dedicated to the 

advancement of aeronautics and space science. The 

NASA scientific and technical information (STI) 

program plays a key part in helping NASA maintain 

this important role. 

The NASA STI program operates under the 

auspices of the Agency Chief Information Officer. 

It collects, organizes, provides for archiving, and 

disseminates NASA’s STI. The NASA STI 

program provides access to the NTRS Registered 

and its public interface, the NASA Technical 

Reports Server, thus providing one of the largest 

collections of aeronautical and space science STI in 

the world. Results are published in both non-NASA 

channels and by NASA in the NASA STI Report 

Series, which includes the following report types: 

x TECHNICAL PUBLICATION. Reports of 

completed research or a major significant phase 

of research that present the results of NASA 

Programs and include extensive data or 

theoretical analysis. Includes compilations of 

significant scientific and technical data and 

information deemed to be of continuing 

reference value. NASA counter-part of peerreviewed formal professional papers but has 

less stringent limitations on manuscript length 

and extent of graphic presentations. 

x TECHNICAL MEMORANDUM. Scientific 

and technical findings that are preliminary or of 

specialized interest, e.g., quick release reports, 

working papers, and bibliographies that contain 

minimal annotation. Does not contain extensive 

analysis. 

x CONTRACTOR REPORT. Scientific and 

technical findings by NASA-sponsored 

contractors and grantees. 

x CONFERENCE PUBLICATION. 

Collected papers from scientific and 

technical conferences, symposia, seminars, 

or other meetings sponsored or 

co-sponsored by NASA. 

x SPECIAL PUBLICATION. Scientific, 

technical, or historical information from 

NASA programs, projects, and missions, 

often concerned with subjects having 

substantial public interest. 

x TECHNICAL TRANSLATION. 

English-language translations of foreign 

scientific and technical material pertinent to 

NASA’s mission.

Specialized services also include organizing 

and publishing research results, distributing 

specialized research announcements and feeds, 

providing information desk and personal search 

support, and enabling data exchange services. 

For more information about the NASA STI 

program, see the following: 

x Access the NASA STI program home page 

at http://www.sti.nasa.gov

x E-mail your question to help@sti.nasa.gov

x Phone the NASA STI Information Desk at 

757-864-9658 

x Write to: 

 NASA STI Information Desk 

 Mail Stop 148 

 NASA Langley Research Center 

 Hampton, VA 23681-2199
National Aeronautics and 

Space Administration 

Langley Research Center 

Hampton, Virginia 23681-2199 

 

January 2015 

NASA/TP2015-218674 

NESC-RP-13-00884 

 

Spin Forming Aluminum Crew Module (CM) 

Metallic Aft Pressure Vessel Bulkhead 

(APVBH) – Phase II 

Eric K. Hoffman and Marcia S. Domack 

Langley Research Center, Hampton, Virginia 

Pablo D. Torres and Preston B. McGill 

Marshall Space Flight Center, Huntsville, Alabama 

Wesley A. Tayon 

Langley Research Center, Hampton, Virginia 

Jay E. Bennett 

Johnson Space Center, Houston, Texas 

Joseph T. Murphy 

Lockheed Martin Space Systems Company, New Orleans, Louisiana 
Available from: 

NASA STI Program / Mail Stop 148 

NASA Langley Research Center 

Hampton, VA 23681-2199 

Fax: 757-864-6500 

Acknowledgments 

The team acknowledges Ryan Cullen, Mark Misiag, James Collins, Richard 

Morganti, and Geri Hayes of Spincraft for their expertise in spin forming and their 

dedicated support during the fabrication of the spin formed aft bulkhead evaluated 

in this study. 

Also, the team acknowledges the support of Harold Claytor, Stewart Walker, Jim 

Baughman, and Joel Alexa of LaRC support contractor AMA and the LaRC Light 

Alloy Laboratory for their materials processing, mechanical testing, and 

metallurgical analysis support; and Carlos Castillo, Rolando Padilla, John Savage, 

and Johnnie West of LaRC for their dedication during specimen fabrication. 

The team wishes to acknowledge the support of Lisa Sharff, Charles Kay, David 

Beaty, Matt Jackson, Tafton Hastings of MSFC engineering support contractor 

ESSSA/Jacobs, and Wendell DeWeese (MSFC) for their dedicated support for 

tensile, stress corrosion cracking (SCC), fracture testing, and metallurgical 

analysis support. The team appreciates the dedicated support of Ayman Girgis 

(ESSSA/Jacobs) for his tensile and fracture toughness assessment and PoShou 

Chen (ESSSA/Jacobs) for his microstructural and failure analysis assessment. 

Thank you also to Norm Elfer (LM), Steve Gentz (NESC), Lucie Johannes (JSC), 

Kirby Lawless (NESC), Sandeep Shah (MSFC), and Tim Vaughn (MSFC) for 

their comprehensive peer review. 

The use of trademarks or names of manufacturers in the report is for accurate reporting and does not 

constitute an official endorsement, either expressed or implied, of such products or manufacturers by the 

National Aeronautics and Space Administration. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #:

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

1 of 223

NESC Request No.: TI-13-00884 

Spin Forming Aluminum Crew Module (CM) Metallic 

Aft Pressure Vessel Bulkhead (APVBH) – Phase II 

November 20, 2014 

 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

2 of 223

NESC Request No.: TI-13-00884 

Report Approval and Revision History 

NOTE: This document was approved at the November 20, 2014, NRB. This document was 

submitted to the NESC Director on December 10, 2014, for configuration control. 

Approved: Original Signature on File 12/11/14 

NESC Director Date 

Version Description of Revision Office of Primary 

Responsibility Effective Date 

1.0 Initial Release Dr. Robert Piascik, 

NASA Technical 

Fellow for Materials, 

LaRC 

11/20/14

 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

3 of 223

NESC Request No.: TI-13-00884 

Table of Contents 

1.0 Notification and Authorization ................................................................................................... 11

2.0 Signature Page .............................................................................................................................. 12

3.0 Team List ...................................................................................................................................... 13

3.1 Acknowledgements ........................................................................................................... 13

4.0 Executive Summary ..................................................................................................................... 15

5.0 Background .................................................................................................................................. 19

5.1 Goals and Objectives ........................................................................................................ 22

5.2 Spin Formed Aft-Bulkhead Pathfinder ............................................................................. 22

6.0 Aft-Bulkhead Spin Forming Pathfinder: ................................................................................... 22

6.1 Requirements and Specifications ...................................................................................... 22

6.2 Material Specifications ..................................................................................................... 24

7.0 Spin Forming Manufacturing Process ....................................................................................... 25

7.1 Manufacturing of Aft Bulkhead ........................................................................................ 25

7.2 Material Procurement ....................................................................................................... 25

7.3 Inspection of Raw Plate .................................................................................................... 26

7.4 Machining and Preparation of Forming Blank ................................................................. 26

7.5 Annealing of Spin Forming Blank .................................................................................... 26

7.6 Spin Form Process ............................................................................................................ 26

7.7 Post Spin Forming Inspection ........................................................................................... 27

7.8 Heat Treatment to the T62 Temper ................................................................................... 30

7.9 Final Product Inspection ................................................................................................... 31

7.10 Coupon Blank Machining ................................................................................................. 34

8.0 Aft Bulkhead Test and Analysis ................................................................................................. 38

8.1 Test and Analysis Procedures ........................................................................................... 39

8.2 Metallurgical Analysis ...................................................................................................... 39

8.3 Tensile Test Procedures .................................................................................................... 41

8.4 Fracture Toughness Test Procedures ................................................................................ 47

8.5 Stress Corrosion Test Procedures ..................................................................................... 53

8.6 Seacoast Exposure SCC Test Plan .................................................................................... 64

9.0 LM Test Plan ................................................................................................................................ 66

9.1 Self-Reacting FSW and FPPW Development ................................................................... 66

9.2 Mechanical Property and Structural Subcomponent Testing ............................................ 68

10.0 Results and Discussion ................................................................................................................. 70

10.1 Metallurgical Analysis ...................................................................................................... 70

10.1.1 Thickness Measurements .................................................................................................. 70

10.1.2 Microstructural Analysis ................................................................................................... 72

10.2 Tensile Test Results .......................................................................................................... 88

10.2.1 Uniformity of Tensile Properties ...................................................................................... 90

10.2.2 Comparison with Handbook Data and Other T6 and T8 Products ................................. 116

10.2.3 Tensile Fractography ...................................................................................................... 124

10.3 Fracture Toughness Test Results .................................................................................... 128

10.3.1 Uniformity of Fracture Properties ................................................................................... 129
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

4 of 223

NESC Request No.: TI-13-00884 

10.3.2 Fractography ................................................................................................................... 140

10.3.3 Comparison with Handbook Data and Other T6 and T8 Products ................................. 142

10.4 SCC Test Results ............................................................................................................ 145

10.4.1 Alternate Immersion Test Results ................................................................................... 146

10.4.1.1 30-day Alternate Immersion Exposure Test Results ...................................... 146

10.4.1.2 90-day Alternate Immersion Exposure Test Results ...................................... 148

10.4.1.3 Discussion of Alternate Immersion Exposure Test Results............................ 148

10.4.2 Salt Spray Test Results ................................................................................................... 149

10.4.2.1 30-day Salt Spray Exposure Test Results ....................................................... 149

10.4.2.2 90-day Salt Spray Exposure Test Results ....................................................... 150

10.4.3 Comparison with Handbook Data and Other T6 and T8 Products ................................. 150

10.4.4 Discussion of Stress Corrosion Results .......................................................................... 152

11.0 Supplemental Mechanical Test Program ................................................................................. 170

11.1 Tensile ........................................................................................................................... 171

11.2 Fracture Toughness ......................................................................................................... 172

11.3 Stress Corrosion .............................................................................................................. 173

12.0 Findings, Observations, and NESC Recommendations.......................................................... 175

12.1 Findings .......................................................................................................................... 175

12.2 Observations ................................................................................................................... 177

12.3 NESC Recommendations ............................................................................................... 178

13.0 Alternate Viewpoint ................................................................................................................... 179

14.0 Other Deliverables ..................................................................................................................... 179

15.0 Lessons Learned ......................................................................................................................... 179

16.0 Recommendations for NASA Standards and Specifications .................................................. 179

17.0 Definition of Terms .................................................................................................................... 179

18.0 Acronyms List ............................................................................................................................ 180

19.0 References ................................................................................................................................... 182

20.0 Appendices .................................................................................................................................. 185

20.1 Appendix A: Temper Designations ............................................................................... 185

20.2 Appendix B: Material Certification ............................................................................... 185

20.3 Appendix C: Fracture Toughness Data .......................................................................... 187

List of Figures 

Figure 5.0-1. Welded MPCV CM Configuration ................................................................................... 19

Figure 5.0-2. Schematic of the Metal Spinning Process ......................................................................... 20

Figure 6.1-1. Proposed Aft Bulkhead Pathfinder Configuration ............................................................ 23

Figure 7.6-1. Convex Spin Forming Of The Aft Bulkhead. ................................................................... 27

Figure 7.7-1. Schematic of Forming Inspection Template showing Numbered Locations of 

Ultrasonic Thickness Measurements ................................................................................ 28

Figure 7.7-2. Thickness Profile of the Aft Bulkhead based on Ultrasonic Thickness Measurements 

at the Locations shown in Figure 7.7-1 ............................................................................. 30

Figure 7.8-1. Aft Bulkhead Following Heat Treatment.......................................................................... 31
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

5 of 223

NESC Request No.: TI-13-00884 

Figure 7.9-1. Section of Laser Scan showing the Locations of Thickness Determinations ................... 32

Figure 7.9-2. Thickness Measurements of the Aft Bulkhead determined from the Laser Scan 

Data compared with the UT Measurements ...................................................................... 34

Figure 7.10-1. Aft Bulkhead Coupon Cut Plan ........................................................................................ 35

Figure 7.10-2. Aft Bulkhead following Extraction of Coupon Blanks for Test and Analysis ................. 35

Figure 7.10-3. Coupon Blank Marking Scheme ....................................................................................... 36

Figure 8.2-1. Aft Bulkhead Cut Plan showing the Location of the Metallurgical Analysis Strip 

Highlighted in Yellow. ..................................................................................................... 40

Figure 8.2-2. Metallurgical Analysis Blank showing the Locations of Specimens L7-1 through 

L7-5 ................................................................................................................................... 41

Figure 8.2-3. Thermally Processed Test Blocks. .................................................................................... 41

Figure 8.3-1. Aft Bulkhead Cut Plan showing the Location of the Tensile Coupon Blanks 

highlighted in Yellow ....................................................................................................... 42

Figure 8.3-2. Round Subsize Tensile Specimen Design used for Testing in the L and LT 

Orientations ....................................................................................................................... 43

Figure 8.3-3. Round Subsize Tensile Specimen Design used for Testing in the ST and ST45 

Orientations ....................................................................................................................... 44

Figure 8.3-4. Tensile Test Load Stand, Specimen, and Instrumentation. ............................................... 46

Figure 8.3-5. Typical Stress-Strain Curve for the Spin Formed Al 2219-T62 Aft Bulkhead 

Material in the L Orientation; Coupon Blank L2, Specimen T-L2-L-13. ......................... 47

Figure 8.4-1. Aft Bulkhead Cut Plan showing the Location of the Fracture Toughness 

Coupon Blanks highlighted in Yellow. ............................................................................. 48

Figure 8.4-2. JIC Fracture Toughness Specimen Design; L-T and T-L Orientations. ............................. 49

Figure 8.4-3. JIC Fracture Toughness Specimen Design; S-T Orientation ............................................. 49

Figure 8.4-4. JIC fracture Toughness Specimen and Test Apparatus. ..................................................... 51

Figure 8.4-5. JIC Fracture Toughness R-Curve Plot. ............................................................................... 52

Figure 8.4-6. Typical JIC Fracture Toughness R-Curve Plot .................................................................. 52

Figure 8.4-7. Typical Cross-Sectional Fracture Surface of a JIC Fracture Toughness Specimen ........... 53

Figure 8.5-1. Aft Bulkhead Cut Plan showing the Location of the SCC Coupon Blanks 

highlighted in Yellow ....................................................................................................... 54

Figure 8.5-2. Round Sub-Size Tensile Specimen Design used for SCC Testing ................................... 55

Figure 8.5-3. Cut Plan for Machining SCC Specimens from Coupon Blank M7 

(specimens CP-406-1 through CP-406-42). ...................................................................... 56

Figure 8.5-4. Cut Plan for Machining SCC Specimens from Coupon Blank M8 

(specimens CP-406-43 through CP-406-84). .................................................................... 57

Figure 8.5-5. Cut Plan for Machining SCC Specimens from Coupon Blank M9 

(specimens CP-406-85 through CP-406-126). .................................................................. 58

Figure 8.5-6. Cut Plan for Machining SCC Specimens from Coupon Blank M10 

(specimens CP-406-127 through CP-406-189). ................................................................ 59

Figure 8.5-7. (a) Stressing Device and (b) Representative Stressed Specimens and Stressing 

Frames ............................................................................................................................... 62

Figure 8.5-8. (a) Alternate Immersion Test Apparatus and (b) Salt Spray Chamber ............................. 62

Figure 8.6-1. Aft Bulkhead Cut Plan showing the Location of the Seacoast Exposure SCC 

 Coupon Blanks highlighted in Yellow ............................................................................. 65

Figure 9.1-1. Aft Bulkhead Cut Plan showing the Location of the FSW and FPPW Schedule 

Development Coupon Blanks ........................................................................................... 67
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

6 of 223

NESC Request No.: TI-13-00884 

Figure 9.2-1. Aft Bulkhead Cut Plan showing the Location of the Supplemental Mechanical 

Property Test Coupon Blanks highlighted in Yellow ....................................................... 69

Figure 9.2-2. Schematic showing the Simulated Location for Backbone Panel 6 Connection to Aft 

Bulkhead Joint .................................................................................................................. 70

Figure 10.1-1. Thickness Profile of Coupon Blank L7 compared with the UT and Laser Scan Data ...... 72

Figure 10.1-2. Through-Thickness Microstructures of the Aft Bulkhead at Locations along the 0°

Meridian ............................................................................................................................ 73

Figure 10.1-3. Microstructure at the IML, t/8, t/4, 3t/8, t/2, 5t/8, 3t/4, 7t/8, and OML Throughthickness Positions for (a) L7-1, (b) L7-2, (c) L7-3, (d) L7-4, and (e) L7-5 

Locations along the 0° Meridian. ...................................................................................... 76

Figure 10.1-4. Through-thickness Microstructures of the Thermally Processed Test Blocks. ................. 78

Figure 10.1-5. Microstructure at the IML, t/2, 5t/8, 3t/4, 7t/8, and OML Through-thickness 

Positions for the (a) T4 and (b) T6 Thermally Processed Test Blocks. ............................ 80

Figure 10.1-6. Microstructure of Aft Bulkhead Locations L7-1 through L7-5 compared with the T6 

Thermally Processed Test Blocks at Through-thickness Positions (a) IML, (b) t/2, (c) 

5t/8, (d) 3t/4, (e) 7t/8, and (f) OML. ................................................................................. 87

Figure 10.2-1. Aft Bulkhead Cut Plan showing the Location of the Tensile Coupon Blanks 

highlighted in Yellow ....................................................................................................... 89

Figure 10.2-2. Average Longitudinal (L) Tensile Properties Superimposed on the Aft Bulkhead 

Cut Plan........................................................................................................................... 101

Figure 10.2-3. Average Long Transverse (LT) Tensile Properties Superimposed on the Aft 

Bulkhead Cut Plan .......................................................................................................... 102

Figure 10.2-4. Average Short Transverse (ST) Tensile Properties Superimposed on the Aft 

Bulkhead Cut plan .......................................................................................................... 103

Figure 10.2-5. Average Short Transverse 45° (ST45) Tensile Properties Superimposed on the Aft 

Bulkhead Cut Plan .......................................................................................................... 104

Figure 10.2-6. Longitudinal (L) Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead 

Material as a Function of Arc Length Distance from the Pole along the 0° to 180° 

Meridian Angle ............................................................................................................... 105

Figure 10.2-7. Long Transverse (LT) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Arc Length Distance from the Pole along the 0° to 

180° Meridian Angle ...................................................................................................... 106

Figure 10.2-8. Longitudinal (L) Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead 

Material as a Function of Arc Length Distance from the Pole Along the 90° to 270° 

Meridian Angle ............................................................................................................... 107

Figure 10.2-9. Long Transverse (LT) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Arc Length Distance from the Pole along the 

90° to 270° Meridian Angle ............................................................................................ 108

Figure 10.2-10. Short Transverse (ST) Tensile Properties Of The Spin Formed Al 2219-T62 Aft 

Bulkhead Material As A Function Of Arc Length Distance from the Pole along 

the 0° to 180° Meridian Angle ........................................................................................ 109

Figure 10.2-11. Short Transverse 45o

 (ST45) tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Arc Length Distance from the Pole along the 

0° to 180° Meridian Angle .............................................................................................. 110
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

7 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-12. Short Transverse (ST) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Arc Length Distance from the Pole along the 

90° to 270° Meridian Angle ............................................................................................ 111

Figure 10.2-13. Short Transverse 45o

 (ST45) Tensile Properties of the Spin Formed Al 2219-T62 

Aft Bulkhead Material as a Function of Arc Length Distance from the Pole along the 

90° to 270° Meridian Angle ............................................................................................ 112

Figure 10.2-14. Longitudinal (L) Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead 

Material as a Function of Meridian Angle along the R35 Circumferential Arc 

Length ............................................................................................................................ 113

Figure 10.2-15. Long Transverse (LT) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Meridian Angle along the R35 Circumferential 

Arc Length ...................................................................................................................... 114

Figure 10.2-16. Short Transverse (ST) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a function of Meridian Angle along the R35 Circumferential 

Arc Length ...................................................................................................................... 115

Figure 10.2-17. Short Transverse 45° (ST45) Tensile Properties of the Spin Formed Al 2219-T62 

Aft Bulkhead Material as a function of Meridian Angle along the R35 

Circumferential Arc Length ............................................................................................ 116

Figure 10.2-18. Representative Macroscopic view of the Fracture Surfaces from the top and 

side views for Tensile Specimens L1-L-3 (left), L2-L-14 (middle), and L2-LT-16 

(right) .............................................................................................................................. 125

Figure 10.2-19. SEM Images of the Fracture Surface of Tensile Specimen L2-L-14 at a) 14x; 

b) 50x; c) 500x and d) 2,000x Magnifications ................................................................ 126

Figure 10.2-20. SEM Images of the Fracture Surface of Tensile Specimen ST-43 at (a) 25x; 

(b) 50x; (c) 500x and (d) 2,000x Magnifications ............................................................ 127

Figure 10.2-21. SEM Images of the Fracture Surface of Tensile Specimen ST45-12 at (a) 25x; 

(b) 50x; (c) 500x and (d) 2,000x Magnifications ........................................................... 128

Figure 10.3-1. Aft Bulkhead Cut Plan showing the Location of the fracture Coupon Blanks 

highlighted in Yellow ..................................................................................................... 129

Figure 10.3-2. Fracture Toughness Data as a Function of Orientation. .................................................. 131

Figure 10.3-3. Fracture Toughness Data as a Function of Coupon Blank Location and Grain 

Orientation ...................................................................................................................... 133

Figure 10.3-4. Fracture Toughness Data as a Function of Arc Length Distance from Pole for the 

0° to 180° Meridian ........................................................................................................ 134

Figure 10.3-5. Fracture Toughness Data as a Function of Arc Length Distance from Pole for the 

90° to 270° Meridian. ..................................................................................................... 135

Figure 10.3-6. Fracture Toughness Data as a Function of Meridian Angle for Arc Length 

Distance of 36 inches. ..................................................................................................... 136

Figure 10.3-7. Fracture Toughness Data as a Function of Meridian Angle for Arc Length 

Distance of 55 inches. ..................................................................................................... 137

Figure 10.3-8. J-R Curve for Spin Formed Al 2219-T62 Aft Bulkhead Material in the L-T 

Orientation; Coupon Blank M3, Specimen CP-406-223. ............................................... 138

Figure 10.3-9. J-R Curve for Spin Formed Al 2219-T62 Aft Bulkhead Material in the T-L 

Orientation; Coupon Blank M3, Specimen CP-406-228. ............................................... 139

Figure 10.3-10. J-R Curve for Spin Formed Al 2219-T62 Aft Bulkhead Material in the S-T 

Orientation; Coupon Blank M3, Specimen CP-406-233 ................................................ 140
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

8 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-11. Photomicrograph of Fracture Surface of T-L Fracture Specimen from Coupon 

Blank M2 ........................................................................................................................ 141

Figure 10.3-12. Photomicrograph of Fracture Surface of L-T Fracture Specimen from Coupon 

Blank M2 ........................................................................................................................ 141

Figure 10.3-13. Photomicrograph of Fracture Surface of S-T Fracture Specimen from Coupon 

Blank M2 ........................................................................................................................ 142

Figure 10.3-14. Fracture Toughness Comparison between Spin Formed Al 2219-T62 Aft Bulkhead 

Material and Al 2219-T87 Plate ..................................................................................... 144

Figure 10.3-15. Fracture Toughness Comparison between Spin Formed Al 2219-T62 Aft Bulkhead 

Material and other Al 2219 Tempers in the T-L Orientation .......................................... 145

Figure 10.4-1. Aft Bulkhead Cut Plan showing the location of the SCC Coupon Blanks highlighted 

in Yellow......................................................................................................................... 146

Figure 10.4-2. Photomicrographs of Representative SCC Specimens obtained from Coupon blank 

M7 following 3.5% NaCl Alternate Immersion Exposure (30-day test) ........................ 157

Figure 10.4-3. Photomicrographs of Representative SCC Specimens obtained from Coupon Blank 

M8 following 3.5% NaCl Alternate Immersion Exposure (30-day test) ........................ 158

Figure 10.4-4. Photomicrographs of Representative SCC Specimens obtained from Coupon Blank 

M9 following 3.5% NaCl Alternate Immersion Exposure (30-day test) ........................ 159

Figure 10.4-5. Photomicrographs of Representative SCC Specimens obtained from Coupon Blank 

M10 following 3.5% NaCl Alternate Immersion Exposure (30-day test) ...................... 160

Figure 10.4-6. Photomicrographs of Representative SCC Specimens obtained from Various Coupon 

Blanks following 3.5% NaCl Alternate Immersion Exposure (90-day test) ................... 168

Figure 20.2-1. Material Certification Report for the 2219-F Plate ......................................................... 186

List of Tables 

Table 7.2-1. Chemical Composition, wt % ........................................................................................... 25

Table 7.7-1. Ultrasonic Thickness Measurements of the Aft Bulkhead corresponding to 

Locations 5 through 20 shown in Figure 7.7-1. ................................................................ 29

Table 7.9-1. Thickness Measurements of the Aft Bulkhead based on Laser Tracking Scans of the 

IML and OML. ................................................................................................................. 33

Table 7.10-1. Location and Orientation of Coupon Blanks. ................................................................... 37

Table 7.10-2. Coupon Blank Designation, Test Center, and Test Type .................................................. 38

Table 8.3-1. Tensile Coupon Blank Size, Locations, and Orientations ................................................ 42

Table 8.3-2. Tensile Test Matrix for the Aft Bulkhead. ........................................................................ 45

Table 8.4-1. Fracture Toughness Coupon Blank Locations and Orientations....................................... 48

Table 8.4-2. Fracture Test Matrix for the Aft Bulkhead. ...................................................................... 50

Table 8.5-1. SCC Coupon Blank Locations and Orientations............................................................... 54

Table 8.5-2. 30-day SCC Test Matrix for the Spin Formed Aft Bulkhead Al 2219-T62 Material ....... 60

Table 8.5-3. 90-day SCC Test Matrix for the Spin Formed Aft Bulkhead Al 2219-T62 Material ....... 61

Table 8.5-4. 30-day SCC Test Matrix for the Spin Formed Aft Bulkhead Al 2219-T62 Material ....... 61

Table 8.5-5. 90-day SCC Test Matrix for the Spin Formed Aft Bulkhead Al 2219-T62 Material ....... 61

Table 8.6-1. Seacoast Exposure SCC Coupon Blank Locations and Orientations................................ 65

Table 8.6-2. Test Matrix for the Seacoast Exposure SCC Tests. .......................................................... 66

Table 9.1-1. FSW and FPPW Schedule Development Coupon Blank Locations 

and Orientations ................................................................................................................ 67
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

9 of 223

NESC Request No.: TI-13-00884 

Table 9.2-1. LM Mechanical Property Test Coupon Blank Locations and Orientations. ..................... 69

Table 10.1-1. Thickness Measurements of Coupon Blank L7 at Distances from the Pole. .................... 71

Table 10.2-1. Tensile Coupon Blank Locations and Orientations. ......................................................... 90

Table 10.2-2. Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead Material, 

Longitudinal (L) Orientation............................................................................................. 91

Table 10.2-3. Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead Material, LongTransverse (LT) Orientation. ............................................................................................ 92

Table 10.2-4. Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead Material, Short 

Transverse (ST) Orientation. ............................................................................................ 93

Table 10.2-5. Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead Material, Short 

Transverse 45° (ST45) Orientation. .................................................................................. 94

Table 10.2-6. Average Tensile Properties and Standard Deviations of the Spin Formed 

Al 2219-T62 Aft Bulkhead Material, Longitudinal (L) Orientation. ................................ 95

Table 10.2-7. Average Tensile Properties and Standard Deviations of the Spin Formed 

Al 2219-T62 Aft Bulkhead Material, Long Transverse (LT) Orientation. ....................... 96

Table 10.2-8. Average Tensile Properties and Standard Deviations of the Spin Formed 

Al 2219-T62 Aft Bulkhead Material, Short Transverse (ST) Orientation. ....................... 97

Table 10.2-9. Average Tensile Properties and Standard Deviations of the Spin Formed 

Al 2219-T62 Aft Bulkhead Material, Short Transverse 45° (ST45) Orientation. ............ 98

Table 10.2-10. Average Tensile Properties and standard Deviation Values for the Spin Formed 

Al 2219-T62 Aft Bulkhead Material ................................................................................. 98

Table 10.2-11. Design Tensile Properties of Al 2219-T62, T851 and T87 Sheet and Plate ................... 120

Table 10.2-12. Typical tensile Properties of Al 2219-T62, T851, and T87 sheet and plate ................... 120

Table 10.2-13. Average Tensile Properties for the Spin Formed Al 2219-T62 FPVBH Material .......... 121

Table 10.2-14. Tensile Properties of Spin Formed Al 2219-T62 Domes for the Cryogenic 

Propellant Storage and Transfer (CPST) Program .......................................................... 122

Table 10.2-15. Typical Tensile Properties of Spin Formed Al 2219-T62 Domes Commercially 

Produced by Spincraft ..................................................................................................... 123

Table 10.2-16. Minimum Tensile Properties for Al 2219-T6 Forgings and Rolled or Forged Rings ..... 124

Table 10.3-1. Fracture Toughness Coupon Blank Locations and Orientations..................................... 129

Table 10.3-2. Summary of Fracture Data for the Spin Formed Al 2219-T62 Aft Bulkhead 

Material. .......................................................................................................................... 130

Table 10.4-1. SCC Coupon Blank Locations and Orientations............................................................. 146

Table 10.4-2. 30-day SCC Test Results for Spin Formed Al 2219-T62 Aft Bulkhead Material .......... 155

Table 10.4-3. Baseline Tensile Properties of Spin Formed Al 2219-T62 Aft Bulkhead Material ........ 156

Table 10.4-4. Residual tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead 

Material following a 30-day Exposure to 3.5% NaCl Alternate Immersion per 

ASTM G44. .................................................................................................................... 161

Table 10.4-5. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead 

Material following a 30-day Exposure to 3.5% NaCl Alternate Immersion per 

ASTM G44. .................................................................................................................... 162

Table 10.4-6. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead 

Material following a 30-day Exposure to 3.5% NaCl Alternate Immersion per 

ASTM G44. .................................................................................................................... 163
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

10 of 223

NESC Request No.: TI-13-00884 

Table 10.4-7. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead 

Material following a 30-day Exposure to 3.5% NaCl Alternate Immersion per 

ASTM G44. .................................................................................................................... 164

Table 10.4-8. Rating of Spin Formed Al 2219-T62 Aft Bulkhead Material per MSFC-STD-3029 ..... 165

Table 10.4-9. 90-day SCC Test Results for Spin Formed Al 2219-T62 Aft Bulkhead Material .......... 166

Table 10.4-10. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead Material 

following a 90-day exposure to 3.5% NaCl alternate immersion per ASTM G44. ........ 167

Table 10.4-11. 30-day SCC Test Results for Spin Formed Al 2219-T62 Aft Bulkhead Material .......... 169

Table 10.4-12. 90-day SCC Test Results for Spin Formed Al 2219-T62 Aft Bulkhead Material. ......... 169

Table 10.4-13. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead 

Material following Exposure to 5% Salt Spray per ASTM B117. .................................. 169

Table 10.4-14. SCC Test Data for other 2xxx series Al Alloys for Comparison. ................................... 170

Table 10.4-15. Rating of Al 2195-T8 and Al 2219-T87 per MSFC-STD-3029. .................................... 170

Table 11.1-1. Supplemental Tensile Test Matrix .................................................................................. 171

Table 11.2-1. Supplemental Fracture Toughness Test Matrix .............................................................. 172

Table 11.3-1. Supplemental SCC Test Matrix ...................................................................................... 174

 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

11 of 223

NESC Request No.: TI-13-00884 

Technical Assessment Report 

1.0 Notification and Authorization 

The principal focus of this project was to assist the Multi-Purpose Crew Vehicle (MPCV) 

program in developing a spin forming fabrication process for manufacture of the Orion crew 

module (CM) aft pressure vessel bulkhead. The spin forming process will enable a single piece 

aluminum (Al) alloy 2219 aft bulkhead resulting in the elimination of the current multiple piece 

welded construction, simplify CM fabrication, and lead to an enhanced design. Phase I (NASA 

TM-2014-218163, (1)) of this assessment explored spin forming the single-piece CM forward 

pressure vessel bulkhead. 

The MPCV Program and Lockheed Martin (LM) recently made two critical decisions relative to 

the NESC Phase I work scope: (1) LM selected the spin forming process to manufacture a singlepiece aft bulkhead for the Orion CM, and (2) the aft bulkhead will be manufactured from Al 

2219. 

Based on the Program’s new emphasis related to the spin forming process, the NESC was asked 

to conduct a Phase II assessment to assist in the LM manufacture of the aft bulkhead and to 

conduct a feasibility study into spin forming the Orion CM cone. 

This activity was approved on June 19, 2013. Dr. Robert Piascik, NASA Technical Fellow for 

Materials at the Langley Research Center (LaRC), was selected to lead this assessment. The 

project plan was approved by the NASA Engineering and Safety Center (NESC) Review Board 

(NRB) on July 18, 2013. 

The primary stakeholders for this assessment are the NASA and LM MPCV Program offices. 

Additional benefactors are commercial launch providers developing CM concepts. 
NASA Engineering and Safety Center

Technical Assessment Report

Document #:

NESC-RP13-00884

Version:

1.0

Title:

Spin Forming Al CM Metallic APVBH – Phase II

Page #:

12 of 223

NESC Request No.: TI-13-00884

2.0 Signature Page 

Submitted by: 

Dr. Robert S. Piascik Date 

Significant Contributors: 

Mr. Michael D. Squire Date 

Ms. Marcia S. Domack Date 

Mr. Eric K. Hoffman Date 

Signatories declare the findings, observations, and NESC recommendations compiled in the 

report are factually based from data extracted from program/project documents, contractor 

reports, and open literature, and/or generated from independently conducted tests, analyses, and 

inspections. 

5FBN4JHOBUVSF1BHFPO'JMF
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

13 of 223

NESC Request No.: TI-13-00884 

3.0 Team List 

Name Discipline Organization 

Core Team 

Robert Piascik NESC Lead LaRC 

Michael Squire NESC Deputy Lead LaRC 

Marcia Domack Project Technical Lead LaRC 

Eric Hoffman Project Aft Bulkhead Lead LaRC 

Jay Bennett Materials & Processes JSC 

Peter Curreri Project Coordinator at MSFC MSFC 

Preston McGill Fracture Toughness Assessment MSFC 

Joseph Murphy Materials and Processing LM 

Roger Reinmuller Materials and Processing LM 

Wesley Tayon Metallurgical Analysis LaRC 

Pablo Torres Stress Corrosion Testing and Analysis MSFC 

Consultants 

Mark Cantrell M&P Lead for Orion LM 

Stephen Hales Physical Metallurgy LaRC 

Lucie Johannes Welding/Manufacturing JSC 

Mike Smiles MAF Processing SSC 

John Wagner Manufacturing and Physical Metallurgy LaRC 

Administrative Support 

Linda Anderson MTSO Program Analyst LaRC 

Linda Burgess Planning and Control Analyst LaRC/AMA 

Terri Derby Project Coordinator LaRC/AMA 

Jeffrey Hisey Contracting Officer LaRC 

Erin Moran Technical Writer LaRC/AMA 

3.1 Acknowledgements 

The team acknowledges Ryan Cullen, Mark Misiag, James Collins, Richard Morganti, and Geri 

Hayes of Spincraft for their expertise in spin forming and their dedicated support during the 

fabrication of the spin formed aft bulkhead evaluated in this study. 

Also, the team acknowledges the support of Harold Claytor, Stewart Walker, Jim Baughman, 

and Joel Alexa of LaRC support contractor AMA and the LaRC Light Alloy Laboratory for their 

materials processing, mechanical testing, and metallurgical analysis support; and Carlos Castillo, 

Rolando Padilla, John Savage, and Johnnie West of LaRC for their dedication during specimen 

fabrication. 

The team wishes to acknowledge the support of Lisa Sharff, Charles Kay, David Beaty, Matt 

Jackson, Tafton Hastings of MSFC engineering support contractor ESSSA/Jacobs, and Wendell 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

14 of 223

NESC Request No.: TI-13-00884 

DeWeese (MSFC) for their dedicated support for tensile, stress corrosion cracking (SCC), 

fracture testing, and metallurgical analysis support. The team appreciates the dedicated support 

of Ayman Girgis (ESSSA/Jacobs) for his tensile and fracture toughness assessment and PoShou 

Chen (ESSSA/Jacobs) for his microstructural and failure analysis assessment. 

Thank you also to Norm Elfer (LM), Steve Gentz (NESC), Lucie Johannes (JSC), Kirby Lawless 

(NESC), Sandeep Shah (MSFC), and Tim Vaughn (MSFC) for their comprehensive peer review. 

 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

15 of 223

NESC Request No.: TI-13-00884 

4.0 Executive Summary 

The objective of this project was to assist the Multi-Purpose Crew Vehicle (MPCV) Program in 

developing a spin forming fabrication process for the manufacture of the Orion crew module 

(CM) aft pressure vessel bulkhead (APVBH) and evaluate the feasibility for manufacture of a 

single-piece cone. The spin forming process would enable a single-piece aluminum (Al) alloy 

2219 aft bulkhead and single-piece cone resulting in the elimination of the current multiple piece 

welded construction, simplify CM fabrication, and lead to an enhanced design. The objectives of 

this two-part study were to: (1) spin form a full scale generic aft bulkhead component and 

characterize its properties as a pathfinder for the Lockheed-Martin (LM) Orion CM, and 

(2) develop a first-of-a-kind thick-component (6 inches thick) spin forming process for the 

manufacture of a single piece integrally-machined CM cone that would accommodate all design 

features (i.e., integral stiffeners, window frames, etc.). This report will focus on the aft bulkhead 

portion of this study only. The cone feasibility study determined that the benefits of a singlepiece cone fabricated using spin forming were not sufficient to warrant proceeding with 

fabrication and testing. The single-piece cone feasibility study will be described in a supplement 

to this report. 

The NESC Phase I activity, Spin Forming Aluminum Crew Module (CM) Forward Pressure 

Vessel Bulkhead (FPVBH) (1), demonstrated the feasibility of spin forming a single-piece 

FPVBH using either Al alloys 2219 or 2195. Based on the Phase I feasibility results, the MPCV 

Program requested that a Phase II spin forming activity be conducted to address specific 

objectives (processing and preliminary properties) associated with spin forming the aft bulkhead. 

The MPCV Program and LM recently made two critical decisions relative to the NESC Phase I 

work scope: (1) LM selected the spin forming process to manufacture a single-piece aft bulkhead 

for the Orion CM, and (2) the aft bulkhead will be manufactured from Al 2219. The motivation 

for the change in manufacturing method included eliminating weld lands, lowering overall 

weight, simplifying the design, and improving design analysis and fidelity. The change in 

material was driven by the single-piece aft bulkhead design, which requires a preform thicker 

than 2 inches in order to accommodate all design features. Al-Li 2195 is limited in thickness to 

2 inches or less due to quench rate sensitivity, which results in in-plane and through-thickness 

mechanical property anisotropy. As a result, the spin formed single-piece aft bulkhead design 

requires a corresponding change in material to thicker gage Al 2219. 

The following tasks were defined to validate the spin forming process feasibility and 

demonstrate that acceptable material properties are achieved in a fully processed aft bulkhead: 

1. Develop process parameters and spin form a pathfinder aft bulkhead representative of 

the Orion CM geometry using Al alloy 2219. 

2. Develop a preliminary properties data base using material from the fully processed 

Al 2219-T62 pathfinder aft bulkhead regarding: 

a. Microstructure 

b. Mechanical properties (tensile and fracture toughness) 

c. Stress corrosion cracking (SCC) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

16 of 223

NESC Request No.: TI-13-00884 

3. Develop circumferential (aft bulkhead to barrel) friction stir welding (FSW) 

parameters using material from the pathfinder aft bulkhead (LM activity). 

A pathfinder aft bulkhead was successfully fabricated at a spin forming vendor using standard 

commercial spin forming and heat treatment practices. The curvature and thickness of the 

pathfinder were representative of and scalable to the Orion CM geometry. The aft bulkhead was 

fabricated using a single plate of Al 2219 and was fully processed to the T62 temper. Material 

was provided for metallurgical examination, tensile, fracture toughness, and stress corrosion 

testing by NASA. Additional material was provided to LM for additional mechanical property 

testing, self-reacting friction stir weld (SR-FSW) development for the aft bulkhead-to-CM barrel 

section joint, and structural sub element testing. The goal of these tasks was to address specific 

MPCV Program needs related to spin forming the Orion CM APVBH. The overall goal was to 

reduce risk by assessing a new manufacturing method prior to program deployment, provide 

information to guide first article test and analysis, develop an initial property database, identify 

preliminary issues or “show stoppers,” and accelerate program implementation.

This NESC assessment included microstructure evaluation, tensile and fracture toughness 

property testing, and SCC characterization to develop an initial property database for spin 

formed and heat treated Al 2219. Selected pathfinder regions (acreage locations) were tested to 

assess property uniformity. The resulting properties were compared to existing databases, such 

as Metallic Materials Properties Development and Standardization (MMPDS) to determine 

relative ranking. This study concluded that there were no insurmountable technical issues that 

precluded spin forming an aft bulkhead. Major findings are as follows: 

The microstructure of the aft bulkhead varied both through-thickness and with meridian distance 

from the pole. The primary differences were grain size, extent of recrystallization, and residual 

deformation bands. Strain-induced recrystallized microstructures occurred toward the outer 

mold line (OML) of the aft bulkhead and reflect deformation imparted by the spin forming 

rollers. The recrystallized region extended through more of the section thickness in regions of 

greater deformation, specifically farther from the pole. These variations in grain size in the aft 

bulkhead are indicative of the complex and varied deformation levels associated with the spin 

forming process, particularly when combined with the plate rolling history and post-forming heat 

treatment. Material property tests were performed for in-plane orientations (longitudinal (L) and 

long transverse (LT)) only at the mid-plane (t/2 where t = thickness) location. Depending on the 

microstructure developed in a first article produced by LM for Orion, testing may be warranted 

at other through-thickness positions, particularly those biased toward the OML. 

Tensile properties of the spin formed Al 2219-T62 aft bulkhead material were comparable to the 

MMPDS design properties for T62 wrought plate and other fabricated products in the T6 temper, 

such as spin formed domes, forgings and rolled rings. Tensile strength increased slightly, but 

measurably with distance from the pole and was uniform about the circumference. The short 

transverse (ST) tensile properties were notably greater than those for the other orientations L, 

LT, and 45o to the ST (ST45)), but elongations were about half. The tensile properties were 

lower than for Al 2219-T851 and T87 plate, as expected due to the increased precipitation 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

17 of 223

NESC Request No.: TI-13-00884 

strengthening in T8 temper wrought products that is imparted by the cold work prior to artificial 

aging. 

Fracture toughness values were in-family with conventional Al 2219 tempers and product forms, 

and the typical variation with orientation was observed. Toughness values were higher for the 

spin formed material compared with Al 2219–T87 plate, which is expected for the strength levels 

measured). For 2xxx series Al alloys, strength and toughness are inversely proportional (i.e., T8 

tempers achieve higher strength, but lower toughness. In-plane (L-T and T-L) toughness values 

were relatively constant for a given orientation and did not vary significantly across the aft 

bulkhead acreage. Toughness in the T-L orientation did decrease slightly with distance from the 

pole, which is in agreement with the trend noted for tensile strength. The test results showed 

high toughness values, high toughness-to-yield strength (YS) ratios, and rising R-curve behavior, 

which suggests excellent damage tolerance capability of the aft bulkhead material. In order to 

more fully characterize the damage tolerance capability of the material, the NESC team 

recommends conducting fatigue crack growth rate and surface crack tension testing on the aft 

bulkhead material. 

Stress corrosion resistance varied with location and orientation, ranging from the equivalent of 

Table I to Table III ratings as per MSFC-STD-3029. The L and LT orientations were 

significantly more resistant to SCC than the ST orientation. The primary data of interest is the 

30-day alternate immersion exposure. Results from this test method and test duration are 

typically the basis for handbook and table ratings for SCC resistance. No failures occurred for 

the LT orientation, even at the highest stress levels, and all specimens had passing post-exposure 

residual strength levels. Susceptibility to SCC in the ST orientation varied with location in the 

aft bulkhead with the highest SCC resistance occurring at the rim. Regions near the pole and 

some in the membrane had moderate SCC resistance. One SCC failure of an ST specimen from 

a membrane location occurred at a low enough exposure stress level to warrant concern, and if 

validated would result in a Table III rating for the spin formed aft bulkhead material. More 

importantly, the allowable design stress may need to be reduced. 

However, some important points must be noted regarding this data. The aft bulkhead tests 

followed MSFC test standard MSFC-STD-3029 in which the exposure stress levels are based on 

the measured strength of the material. Handbook values are based on standards that use 

MMPDS A-basis allowables to determine exposure stress levels. Actual strength is always 

higher than the allowables due to statistical knockdown; consequently, the aft bulkhead 

specimens were exposed to higher stress levels than handbook data being used for comparison. 

Al 2219 is considered an isotropic material with properties in the L, LT, and ST orientations 

generally agreeing within less than 5%. The ST YS in the aft bulkhead was 10% greater than 

that for L and LT. While it is unclear whether the high ST YS is inherent in the plate used in 

fabrication of the spin forming blank or is related to the spin forming process, the high ST YS of 

the aft bulkhead material further increased the exposure stress levels. The MSFC standard is 

realistic in that actual material strength will govern the performance of fabricated hardware. 

However, the difference in exposure stress levels makes interpretation of the aft bulkhead data 

more difficult. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

18 of 223

NESC Request No.: TI-13-00884 

The test duration specified by MSFC-STD-3029 is an additional deviation from recommended 

practice. One disadvantage of the 3.5% NaCl alternate immersion test is that severe pitting may 

develop in the test specimens. As per ASTM G47, such pitting in tensile specimens with 

relatively small cross-sections can markedly reduce the effective cross-sectional area and result 

in net sectional stresses greater than nominal gross section stress. This end result is that the 

pitting may interfere with the valid evaluation of the SCC resistance of the material. For this 

reason, ASTM G47 and G64 recommend a 10-day alternate immersion exposure period for 2xxx 

series Al alloys when tested in the ST orientation and a 40-day exposure period when tested in 

the L and LT orientations. These exposure periods are believed to be long enough to detect 

susceptibility to intergranular SCC yet short enough to avoid excessive pitting that can lead to 

failure by another mechanism. General pitting, which served as initiation sites for SCC, was 

noted in the aft bulkhead material following 30-day alternate immersion exposure. The NESC 

team recommends that further evaluation of the aft bulkhead material be evaluated at shorter 

exposure times. 

For alloys requiring microstructural control to avoid susceptibility to SCC, resistance is obtained 

by using heat treatments that produce uniform precipitation throughout the microstructure. The 

susceptibility of the Al 2219 aft bulkhead material to SCC is further exacerbated by the T62 

temper, which results in a non-uniform distribution of precipitates. Because of the pitting 

potential and a susceptible heat treat temper to SCC, deployment of this material for the aft 

bulkhead may require a materials usage agreement (MUA) prior to acceptance for service. 

Interpreting the significance of the SCC results was difficult due to the small data sets generated 

and the limited SCC data available in handbooks and open literature publications for 

Al 2219-T6. While the SCC results provide insight about the performance of spin formed 

Al 2219-T62 material, the data sets were insufficient to establish a threshold stress level for 

SCC, information that is of high importance to the LM Orion design team. The NESC team 

recommends that additional SCC testing be performed on serial aft bulkheads to define the SCC 

threshold. Additionally, SCC testing of Al 2219-T6 wrought products should be performed to 

generate sufficient data to substantiate handbook and table ratings of the SCC resistance of Al 

2219. Finally, in order to understand the impact of the SCC susceptibility of the material on 

fracture toughness and fatigue, the NESC team recommends evaluating environmentally assisted 

cracking fracture toughness (KEAC) and fatigue ((da/dN)SCC) in the S-T orientation in a 3.5% 

NaCl solution. 

Based upon the findings and observations, recommendations for follow-on testing to be 

conducted by Orion are made. A supplemental mechanical property test program designed to 

address key findings and observations is also presented. These supplemental mechanical 

property test results will be issued as an addendum report to be published at a later date. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

19 of 223

NESC Request No.: TI-13-00884 

5.0 Background 

The primary structural elements of the Orion welded crew module (WCM), shown in 

Figure 5.0-1, consist of a single piece forged barrel, a multi-piece cone section, a single piece 

forward bulkhead, a single piece forward tunnel, integrated forward gussets, and a multi-piece 

welded aft bulkhead. The aft bulkhead configuration shown is assembled from Al-Li 2195 using 

one circular and two latitudinal welds. Fabrication of a Al 2219 single-piece aft bulkhead by 

spin forming, as is now planned by the Orion Program, will eliminate these welds, improving 

manufacturing efficiency and reducing the risk associated with welded structure. 

Figure 5.0-1. Welded MPCV CM Configuration 

Spin forming is an established commercial metalworking process used in many industries, 

including fabrication of cryogenic tank domes. In convex spin forming, a circular disc of metal, 

called the forming blank, and a mandrel, whose shape corresponds to the internal contour of the 

part to be produced, are mounted in a spinning lathe (Figure 5.0-2). The blank is clamped 

between mandrel and a follower on the tailstock spindle of the lathe. The mandrel, blank, and 

follower are then set in rotation. During rotation, a forming roller is used to apply localized 

pressure to the blank to gradually form it over the mandrel. The size of the part and the thickness 

and alloy of the forming blank will determine the force required to deform the metal blank to the 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

20 of 223

NESC Request No.: TI-13-00884 

shape (contour) of the mandrel. Heating of the part during spinning (hot forming) is determined 

to meet the force requirements and/or the ductility requirements during forming. 

[Credit: Spincraft] 

Figure 5.0-2. Schematic of the Metal Spinning Process 

[Credit: The Library of Manufacturing – Metal Spinning] 

Spin forming is applicable to most malleable metals and can produce a wide range of part sizes; 

parts can be spun up to 26 feet in diameter and thicknesses of up to 4.5 inches for Al and 

1.5 inches in ferrous alloys. Spin forming is particularly adaptable to rotationally symmetric 

hollow shapes, such as cylinders, cones, and hemispheres and can enable considerable savings in 

both materials and manufacturing costs compared with other fabrication methods. Benefits 

include simple and low cost tooling requirements, involving primarily a contoured spinning 

mandrel, reduced lead times, and increased material yields compared to other forming methods. 

The deformation induced during spin forming is complex and non-uniform. During convex spin 

forming there is generally no deliberate reduction in wall thickness as the material is shaped over 

the mandrel (2). Through-thickness compressive stresses are generated as a result of pressure 

from the forming tool as well as the strains induced during forming of the contour. During 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

21 of 223

NESC Request No.: TI-13-00884 

forming the blank diameter is reduced as material is pushed onto the mandrel, particularly near 

the rim, consequently the material experiences circumferential compressive stress superimposed 

on radial tensile stress, which combine to result in nearly constant wall thickness. The tool 

pressure is fairly uniform from the pole to the rim, but the imposed strain levels likely increase 

due to the superimposed forming stresses (tangential compressive and radial tensile and 

compressive) acting on the material, particularly towards the edge of the forming blank. So 

many process parameters affect material response during spin forming that modeling the process 

has been unsuccessful. The industrial success of spin forming is based on extensive experience 

at the vendors. 

Producing a single-piece aft bulkhead by spin forming is consistent with design for 

manufacturing principles that enable lower manufacturing costs by reducing the number of parts 

and manufacturing steps. Eliminating welds reduces mass by eliminating weld lands and cost 

because post-weld NDE is no longer required. Spin forming has potential weight and production 

cost advantages over the current MPCV welded CM design and provides opportunities for 

improved performance and design margins as a result of design changes made possible using 

spin forming. A single-piece aft bulkhead also enables a simplified design analysis, which 

improves the fidelity of analysis and reduces the risk of analysis errors. 

The components of the CM are constructed from high strength, heat treatable Al alloys such as 

Al 2219 and Al-Li 2195 because they offer high strength-to-weight ratios, good fracture and 

SCC resistance properties, and are weldable via FSW. These alloys are typically used in the T8 

heat treat temper, which involves a solution heat treatment, water quench, and cold work to 

promote precipitation strengthening during subsequent artificial aging heat treatments. The 

thickness of the aft bulkhead is large enough that uniform cold stretch/work cannot be introduced 

after solution heat treatment. Consequently, the final heat treat temper for the aft bulkhead is T6 

(solution heat treat, water quench, and age), which can result in lower strength, greater potential 

for pitting corrosion, and greater susceptibility to SCC compared to T8 temper products. In 

addition, very little data exist in open literature sources on mechanical properties of spin formed 

products. The spin formed aft bulkhead mechanical properties were compared to existing 

databases and standards for both T6 and T8 wrought plate and fabricated product forms to assist 

designers in determining any property knockdowns associated with the spin forming process and 

to provide fundamental material property data sets for manufacturing trade studies. 

Throughout this report the temper designations will follow the Aluminum Association’s 

definitions of T6 being solution heat treated and then artificially aged by the material producer 

and T62 being solution heat treated and then artificially aged by the user. Furthermore, the aft 

bulkhead material was also compared to both wrought plate and fabricated products forms in the 

T851 and T87 temper. T851 temper is solution heat treated, stress-relieved by controlled 

stretching (permanent set 1.5% to 3% for plate) and then artificially aged while T87 temper is 

solution heat treated, cold worked approximately 7% and then artificially aged. 

See Appendix, Section 20.1 for a full description of the temper designations used in this report. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

22 of 223

NESC Request No.: TI-13-00884 

5.1 Goals and Objectives 

The proposed scope of this Phase II project was to spin form an aft bulkhead test article to assess 

the mechanical properties (e.g., tensile, fracture, and SCC) and to provide representative spin 

formed material for LM circumferential FSW development. A second objective was to conduct 

a feasibility study to spin form a 6-inch thick single-piece cone to accommodate integral 

machining of all required structural elements (i.e., window frames, door hatches, etc.). A closer 

investigation of the cone region showed that the thickness requirements were approximately 

8 inches and spin forming using current capabilities was not feasible; therefore, this objective 

was cancelled. A summary of the cone feasibility study will be provided in a supplement to this 

report. 

5.2 Spin Formed Aft-Bulkhead Pathfinder 

This task included spin forming and heat treating a pathfinder article from a single plate of 

Al 2219 (1.5 to 2.5-inch thick) with a diameter and curvature similar to the Orion CM aft 

bulkhead. After fabrication, the pathfinder was sectioned to supply spin formed material to 

support the two following studies that were conducted in parallel. 

i. Material Property Testing: The NESC team conducted a microstructure 

(grain size) evaluation, tensile and fracture toughness property testing, and 

SCC characterization to develop an initial property database for spin formed 

and heat treated Al 2219. Selected pathfinder regions (acreage locations) 

were tested to assess uniformity. 

ii. FSW Development: The NESC team supplied LM with sufficient spin 

formed pathfinder material for an initial FSW development study required to 

optimize the final aft bulkhead pressure vessel circumferential weld. 

Additional material was supplied to support mechanical property and 

structural subcomponent testing by the Orion structural design group. 

6.0 Aft-Bulkhead Spin Forming Pathfinder: 

6.1 Requirements and Specifications 

The preliminary design for the Al 2219 Orion aft bulkhead has a 148.8-inch diameter, a 

229.3-inch radius of curvature, and a 2.6-inch wall thickness. To meet the assessment 

objectives, the NESC team conducted a preliminary engineering analysis to assess manufacturing 

capabilities, tooling requirements, production schedule, and material availability for fabricating 

an aft bulkhead pathfinder component using spin forming technologies currently employed for 

the manufacture of Al alloy cryogenic tank dome structures. The funding level and schedule did 

not support fabrication of tooling (mandrel) required to produce the current Orion design nor 

could it afford long lead times for material delivery and production schedule openings. Based on 

this engineering assessment, Spincraft, a division of the Standex International Corporation, of 

North Billerica, MA, was chosen as the contractor to produce the aft bulkhead pathfinder. 

Among the large-scale spin forming vendors, it was determined that only Spincraft had both the 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

23 of 223

NESC Request No.: TI-13-00884 

capability to produce components with the combined thickness and diameter needed to produce a 

pathfinder component representative of the Orion CM aft bulkhead and had production schedule 

openings to meet the project schedule. To support the aft bulkhead fabrication, Spincraft used an 

existing mandrel designed for a commercial customer that had similar size and geometry to the 

Orion aft bulkhead design. Figure 6.1-1 shows the aft bulkhead pathfinder component that was 

spin formed at Spincraft with dimensions of 135.5-inch diameter, 204.75-inch radius of 

curvature, and a wall thickness of 2.3 inches. Due to long material production lead times from 

Al producers, Spincraft was able to provide a suitably sized Al 2219 plate by diverting a plate 

from an existing production contract. 

Figure 6.1-1. Proposed aft bulkhead pathfinder configuration. Dimensions are based on existing 

mandrel at Spincraft. 

To support Orion in determining the suitability of the spin forming process for fabricating the aft 

bulkhead for the Orion CM, a spin formed pathfinder component was fabricated using standard 

spin forming technologies and practices. The spin formed component was fabricated on a best 

effort basis using existing commercial tooling and commercially-available materials, and was 

subjected to standard industry inspections, company proprietary spin forming processing, and 

post-forming thermal treatments. 

Specifically, Spincraft was tasked with fabricating a pathfinder component through the following 

tasks outlined in the statement of work: 

1. Perform a preliminary engineering analysis to assess the tooling requirements for 

fabricating the pathfinder component using spin forming technologies currently 

employed for manufacture of launch vehicle upper stage Al alloy cryogenic tank 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

24 of 223

NESC Request No.: TI-13-00884 

dome structures. Based on preliminary designs, the component shall have 

approximate dimensions ranging from 100 to 150 inches diameter at the rim, 200 to 

250 inches radius of curvature, and 1.5 to 2.5 inches thick. 

2. Identify existing tooling necessary to support spin forming, heat treatment, and 

machining. Identify and procure Al 2219 plate suitable for manufacturing the 

pathfinder component. 

3. Fabricate the pathfinder component including all preparation of the spin forming 

blank, spin forming operations, inspections, subsequent heat treatment and 

machining. 

4. After all spin forming and post-fabrication processing is complete, section the 

pathfinder component and corner drops from the forming blank per NASA-supplied 

cut plan and ship pieces to NASA LaRC, MSFC, JSC, and LM-MAF. 

5. Prepare a final report on the spin formed pathfinder component fabrication to include 

a detailed description of the tooling and fabrication process and recommendations for 

further process development. 

6.2 Material Specifications 

For the commercial production of Al 2219 spin formed components, Spincraft starts with Al 

2219-F temper plate that meets material certification specifications in accordance with AMS 

QQ-A-250/30 (3). For domes of the size required in the aft bulkhead pathfinder, the minimum 

dimensions required were 2.3 inches thick x 141 inches x 141 inches. The following notes are 

the material specification standards utilized by Spincraft: 

General notes: 

1. Chemical composition shall conform to the specified standard. 

2. Heat treatment response testing is required to demonstrate compliance to the T62 

temper. 

3. Plate shall be ultrasonically inspected for internal defects in accordance with AMSSTD-2154, Class A. 

4. Plate shall be stretched to an amount necessary to achieve flatness of 1.00 inch in any 

72-inch direction. 

5. Provide material certification standards confirming the chemical analyses, mechanical 

property testing after heat treatment, and nondestructive inspection for defects are in 

compliance with AMS QQ-A-250/30. 

6. Heat Lot Number to be marked on the plate surface using black permanent ink 

(STM0257A37038 or equivalent) in accordance with FED-STD-595. 

7. The grain direction is to be identified on each plate by an ink arrow. 

8. Water jet cut plate to form a circular blank of approximately 140-inch diameter. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

25 of 223

NESC Request No.: TI-13-00884 

9. Plate will be packaged for shipment in accordance with AMS-QQ-A-250 Level “C”. 

10. Shipment will include plate corners remaining after cutting circular blank. 

7.0 Spin Forming Manufacturing Process 

7.1 Manufacturing of Aft Bulkhead 

The aft bulkhead was fabricated in accordance with Spincraft’s standard practice for Al spin 

formed domes, process plan 2009FA, and was documented in the final report (4). The 

processing steps used in the production of the aft bulkhead are as follows: 

1. Material procurement 

2. Inspection of raw plate 

3. Machining and preparation of forming blank 

4. Annealing of spin forming blank 

5. Spin form process 

6. Post-spin forming inspection 

7. Heat treatment to the T62 temper 

8. Final product inspection 

9. Coupon blank machining 

7.2 Material Procurement 

The Al 2219-F plate material used by Spincraft to spin form the aft bulkhead measured 

2.3 inches x 141 inches x 141 inches and was supplied by Alcoa North American Rolled 

Products – Davenport Works, Davenport, IA. Chemical analysis was performed to determine the 

composition relative to AMS QQ-A-250/30 specification standards (Table 7.2-1). The plate 

stock was found to be in compliance with material certification AMS QQ-A-250/30 and of the 

proper thickness and size. The material certification supplied with the plate is shown in the 

Appendix (see Section 20.2, Figure 20.2-1). 

Table 7.2-1. Chemical Composition, wt % 

Heat No. H9134063; Lot No. 446391

Si Fe Cu Mn Mg V Zn Ti Zr Each Total Aluminum

Actuals 0.06 0.14 6.3 0.25 0.01 0.09 0.02 0.04 0.13 Balance

Specification AMS-QQ_A-250/30

Si Fe Cu Mn Mg V Zn Ti Zr Each Total Aluminum

Max 0.20 0.30 6.8 0.40 0.02 0.15 0.10 0.10 0.25 0.05 0.15

Min 5.8 0.20 0.05 0.02 0.10 Balance
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

26 of 223

NESC Request No.: TI-13-00884 

7.3 Inspection of Raw Plate 

The incoming inspection of the raw plate consisted of verifying material certification 

specifications, visual inspection for defects, and measurement of plate size and thickness using 

an ultrasonic transmission (UT) inspection and pull tape. The incoming plate stock was found to 

be in compliance to the material certifications and of the proper size and thickness. Thickness of 

the plate was measured at numerous locations using ultrasonic methods and varied from 2.326 to 

2.316 inches. Following inspection, the plate was stamped with the Alcoa plate lot number, 

Spincraft identification number, and plate rolling direction. 

7.4 Machining and Preparation of Forming Blank 

Following inspection, the plate was shipped to a waterjet vendor where it was cut into a circular 

forming blank measuring 140-inch in diameter. It was then re-inspected following return to 

Spincraft and found to be in compliance. 

As per Spincraft’s standard practice for spin forming domes without center holes or manways, 

two central pins were installed in the forming blank to support the blank during spin forming 

operations. 

7.5 Annealing of Spin Forming Blank 

The forming blank was given a full anneal in an air furnace to ensure maximum formability and 

ductility during spin forming operations. This annealing treatment was conducted in accordance 

with AMS 2770 (5) and consisted of a thermal soak at 775°F ± 25°F for a soak time of 3 hours 

followed by a furnace cool at 50°F per hour to 500°F, and an air cool to room temperature. The 

annealing treatment used is the standard practice at Spincraft for spin formed Al 2219 domes. 

7.6 Spin Form Process 

Spincraft uses the convex spin forming process to manufacture domes and bulkheads 

(Figure 7.6-1). The sequence for forming a dome from flat plate consists of a series of sequential 

forming operations, beginning with break forming over a dome-shaped mandrel and then final 

spinning over the mandrel. In this process, a thick circular blank is rigidly clamped at the pole 

between a head stock/mandrel assembly and a tail stock, and the assembly is rotated about its 

central axis. A roller forming tool is used to force the forming blank against the mandrel as it 

translates from the pole to rim along the outer mold line surface (OML or convex side) of the 

rotating blank in multiple forming steps. The force of the roller forming tool against the forming 

blank causes the metal to plastically deform and flow against the mandrel. In the final spin 

forming operation, the dome or bulkhead is spun against the male tool until the desired surface 

contour is achieved to create the final dome configuration. 

The forming blank was installed on the convex spin forming lathe and spin formed to the contour 

of the mandrel as per Spincraft’s standard production practice. Torches were used to heat the 

mandrel and forming blank to the forming temperature of 500 to 700°F. Temperatures were 

monitored with temperature indicating sticks and recorded throughout the spin forming process. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

27 of 223

NESC Request No.: TI-13-00884 

Figure 7.6-1. Convex Spin Forming of the Aft Bulkhead 

7.7 Post Spin Forming Inspection 

Following spin forming, the aft bulkhead was removed from the tooling and visually inspected 

for defects. The inner mold line (IML) surface of the aft bulkhead was inspected with forming 

inspection templates with the same contour shape as the mandrel while the circumference of the 

aft bulkhead was measured with pi tape to verify that the aft bulkhead was in compliance with 

the final part contour and diametric specifications. No visible damage or contour deviations 

were noted. 

The thickness of the aft bulkhead was measured using ultrasonic methods at locations along the 

inspection template noted numerically in Figure 7.7-1. Measurements were made at locations 

5 through 20, spaced 4 inches apart along the meridian line, spanning from 4 to 64 inches from 

the pole. Measurements 12 and 13 were separated by 8 inches. Measurements were made along 

four meridian lines at 90 degree intervals and results for each meridian and the average are 

provided in Table 7.7-1 and shown graphically in Figure 7.7-2. The OML surface of the aft 

bulkhead exhibited a scalloped pattern due to the advance of the forming roller and this is 

reflected in the fluctuation observed in the plotted data in Figure 7.7-2. Despite the fluctuation in 

the curve, overall the thickness decreased from pole to rim. The thickness was a maximum 

within 12 inches of the pole, a minimum at about 54 inches from the pole, and increased again at 

the rim. The maximum change in thickness was approximately 0.089 inches, which corresponds 

to a reduction in thickness of less than 4% during spin forming. 

Spin forming

mandrel

Forming

blank

Roller

forming

tool

Acetylene

torches
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

28 of 223

NESC Request No.: TI-13-00884 

Figure 7.7-1. Schematic of forming inspection template showing numbered locations of ultrasonic 

thickness measurements. The aft bulkhead was measured at locations 5 through 20, with 

measurements made every 4 inches along a meridian line. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

29 of 223

NESC Request No.: TI-13-00884 

Table 7.7-1. Ultrasonic Thickness Measurements of the Aft Bulkhead corresponding to 

Locations 5 through 20 shown in Figure 7.7-1 

Template 

Point 

Distance from 

Pole (in) 

UT Thickness Measurements (in) 

0 deg 180 deg 90 deg 270 deg Average 

20 4 2.311 2.319 2.311 2.310 2.313 

19 8 2.310 2.313 2.314 2.309 2.312 

18 12 2.315 2.314 2.316 2.318 2.316 

17 16 2.294 2.288 2.289 2.286 2.289 

16 20 2.291 2.293 2.295 2.295 2.294 

15 24 2.303 2.307 2.309 2.308 2.307 

14 28 2.275 2.275 2.279 2.275 2.276 

13 32 2.272 2.273 2.264 2.270 2.270 

12 40 2.239 2.251 2.246 2.236 2.243 

11 44 2.272 2.287 2.293 2.282 2.284 

10 48 2.262 2.258 2.259 2.244 2.256 

9 52 2.224 2.241 2.226 2.238 2.232 

8 56 2.245 2.207 2.243 2.212 2.227 

7 60 2.274 2.283 2.290 2.277 2.281 

6 64 2.276 2.284 2.286 2.273 2.280 

5 68 1.965 1.941 1.995 1.948 1.962 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

30 of 223

NESC Request No.: TI-13-00884 

Figure 7.7-2. Thickness Profile of the Aft Bulkhead based on Ultrasonic Thickness Measurements 

at the Locations shown in Figure 7.7-1 

7.8 Heat Treatment to the T62 Temper 

Following final spinning, the Al 2219 aft bulkhead pathfinder was solution heat treated, 

quenched and artificially aged to the T62 temper (Figure 7.8-1). Due to the thickness of the aft 

bulkhead, uniform cold deformation after solution heat treatment, typically used to produce T8 

temper, is not feasible. Therefore, for parts of this size and thickness, Spincraft’s manufacturing 

process can only produce Al spin formed articles in the T62 temper. Thinner spin formed 

products can be produced in a T8 temper, such as the 0.5-inch-thick Shuttle External tank dome 

caps, which were spin formed at room temperature in the T37 condition and heat treated to T87. 

Solution heat treatment, quenching, and artificial aging processes for the aft bulkhead were 

performed per AMS 2770 specifications. This heat treatment consists of solutionizing at 995°F 

± 10°F for a soak time of 3 hours, followed by a quench in 15 to 17% polymer solution type 

1/water quench medium (glycol quench). This quench medium provides uniform wetting of the 

2.20

2.22

2.24

2.26

2.28

2.30

2.32

2.34

0 10 20 30 40 50 60 70

Thickness, in

Distance from Pole, in

Aft Bulkhead Thickness Profile

Ultrasonic Measurements After Spin Forming

Average

0 degree

90

degree

180

degree
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

31 of 223

NESC Request No.: TI-13-00884 

surface and fast, uniform heat transfer thereby reducing distortion problems normally associated 

with water quenched Al. Normally, following solution heat treatment to the T42 temper, spin 

formed Al components are installed on a hydraulic straightener and any out-of-round deviations 

and distortions resulting from the quenching operation are corrected. However, since this spin 

formed aft bulkhead did not have any finished machining sizing or contour requirements, this 

processing step was omitted. The aft bulkhead was then artificially aged at 375°F ± 10°F for 

36 hours to the T62 temper. 

Figure 7.8-1. Aft bulkhead following heat treatment. 

7.9 Final Product Inspection 

Following final heat treatment, hardness and electrical conductivity inspections were performed 

per AMS 2658 (6) to verify proper temper. All inspections were compliant to a T62 temper. An 

outside vendor conducted a laser tracking assessment of both the OML and IML surfaces of the 

aft bulkhead to confirm that the bulkhead meets the specified contour forming profile. 

Measurements were made from the pole to the rim at approximately 0.25 inch increments at 

5-degree intervals and the results were provided electronically. The laser scan data was analyzed 

to determine thickness along one meridian line at the same locations as the UT measurements, as 

illustrated in Figure 7.9-1. The resulting thickness values are shown in Table 7.9-1 and compared 

with the UT data in Figure 7.9-2. Maximum thickness was at a location of approximately 

8 inches from the pole, minimum thickness was at 40 inches, and the overall reduction in 

thickness was 0.086 inches, values, which agree well with the ultrasonic thickness measurements 

shown in Table 7.7-1. Figure 7.9-2 illustrates that the laser scan data also exhibits fluctuations 

related to the surface scalloping. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

32 of 223

NESC Request No.: TI-13-00884 

Figure 7.9-1. Section of Laser Scan showing the Locations of Thickness Determinations 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

33 of 223

NESC Request No.: TI-13-00884 

Table 7.9-1. Thickness Measurements of the Aft Bulkhead Based on Laser Tracking Scans of the 

IML and OML 

Laser Scan 

Thickness (in) Distance from 

Pole (in) 

2.309 0 

2.304 4 

2.323 8 

2.321 12 

2.294 16 

2.286 20 

2.289 24 

2.281 28 

2.247 32 

2.253 36 

2.228 40 

2.229 44 

2.236 48 

2.270 52 

2.245 56 

2.252 60 

2.201 64 

2.604 68 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

34 of 223

NESC Request No.: TI-13-00884 

Figure 7.9-2. Thickness Measurements of the Aft Bulkhead determined from the Laser Scan Data 

compared with the UT Measurements 

7.10 Coupon Blank Machining 

A coupon cut plan was created prior to spinning the bulkhead and was used as a basis for 

locating the coupons to be cut for mechanical property testing, metallurgical analysis, and FSW 

schedule development (Figure 7.10-1). An outside vendor waterjet-machined coupon blanks 

from representative areas from the pole, membrane, and rim regions, as depicted in the cut plan 

and Figure 7.10-2. 

2.20

2.22

2.24

2.26

2.28

2.30

2.32

2.34

0 10 20 30 40 50 60 70

Thickness, in

Distance from Pole, in

Aft Bulkhead Thickness Profile

Ultrasonic Measurements After Spin Forming

Average UT Measurement

Laser Scan
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

35 of 223

NESC Request No.: TI-13-00884 

Figure 7.10-1. Aft Bulkhead Coupon Cut Plan 

Figure 7.10-2. Aft Bulkhead following Extraction of Coupon Blanks for Test and Analysis 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

36 of 223

NESC Request No.: TI-13-00884 

To maintain coupon blank location and orientation reference, every coupon blank was stamped 

with the identifying blank number, plate rolling direction (within 5 degrees), meridian arc length 

distance from the central pole, and meridian angle with respect to the original plate rolling 

direction as depicted in Figure 7.10-3 and Table 7.10-1. 

Figure 7.10-3. Coupon Blank Marking Scheme 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

37 of 223

NESC Request No.: TI-13-00884 

Table 7.10-1. Location and Orientation of Coupon Blanks 

Longitudinal Transverse Meridian Arc Length

Coupon Dimension, Dimension, Angle , from dome CL

Blank in. in. degrees in.

M1 14 12 9° 54-5/8

M2 14 12 13° 36

M3 14 12 30° 16-1/8

M4 14 12 277° 55-1/2

M5 14 12 281° 35-7/8

M6 14 12 225° 35-1/8

M7 14 12 90° 12

M8 14 12 90° 35-1/8

M9 14 12 90° 56-1/4

M10 14 12 190° 35-5/8

J1 14 12 180° 12

J2 14 12 170° 35-5/8

J3 14 12 180° 55-5/8

MF9 14 12 45° 35-1/8

MF10 14 12 114° 40-3/8

MF11 14 12 270° 12

MF12 14 12 328° 40

MF13 14 12 304° 39-7/8

L1 14 12 351° 54-5/8

L2 14 12 347° 36

L3 14 12 330° 16-1/8

L4 14 12 259° 55-1/2

L5 14 12 263° 35-7/8

L6 14 12 135° 35-1/8

L7 CL to R62 4 0° N/A

MF1 N/A N/A 31° 56-3/4

MF2 N/A N/A 64° 56-3/4

MF3 N/A N/A 116° 56-3/4

MF4 N/A N/A 154° 56-3/4

MF5 N/A N/A 206° 56-3/4

MF6 N/A N/A 240° 56-3/4

MF7 N/A N/A 296° 56-3/4

MF8 N/A N/A 329° 56-3/4

Coupon Blank Size Coupon Center Point

Additional coupon blanks were waterjet cut from the remnant plate corners remaining after 

machining of the circular forming blank. To assist in characterizing the effects of spin forming 

processing on the plate microstructure, test blocks from the remnant plate corners were thermally 

processed for the same temperature-time combination associated with the various thermal 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

38 of 223

NESC Request No.: TI-13-00884 

processing steps used in the production of the aft bulkhead (but without any spin form 

deformation). These thermal processing steps include the starting plate condition (F temper), pre 

- spin forming full anneal condition (O temper); solution heat treat condition (T4 temper), and 

the precipitation aged condition (T6 temper). The coupon blanks from the aft bulkhead, remnant 

plate corner material, and thermally processed test blocks were then shipped to the respective 

centers for test and analysis as shown in Table 7.10-2. 

Table 7.10-2. Coupon Blank Designation, Test Center, and Test Type 

Coupon Blank Designation Test Center Test Type 

L1, L2, L3, L4, L5, L6 LaRC Tensile 

L7, F, O, T4, T6 test blocks LaRC Metallurgical analysis 

M1, M2, M3, M4, M5, M6 MSFC Fracture toughness 

M7, M8, M9, M10 MSFC SCC 

J1, J2, J3 JSC/KSC Seacoast exposure SCC1

MF1, MF2, MF3, MF4, MF5, 

MF6 MF7, MF8 MAF FSW development

MF9, MF10, MF11, MF12, 

MF13 MAF Mechanical property and structural subcomponent testing 

1 Specimens for seacoast exposure were diverted to laboratory alternate immersion SCC testing at MSFC. 

8.0 Aft Bulkhead Test and Analysis 

The overall goal of testing and analysis was to examine property uniformity throughout the aft 

bulkhead and to determine how the properties compared with Al 2219 plate and other formed 

components. The Spincraft spin forming process cannot impart cold stretch prior to aging, 

consequently the aft bulkhead was heat treated to the T62 condition. The aft bulkhead 

mechanical properties were evaluated to determine whether results were comparable (in family) 

with T6 products. Comparison with Al 2219-T851 plate was made since this is the condition 

used for elements of the Orion CM that are machined from thick plate and would likely be the 

condition used if a multi-piece welded Al 2219 aft bulkhead were produced. For cases in which 

little or no data were available for T851 plate, comparisons were made with T87 plate. 

Metallurgical analysis and mechanical property (tensile, fracture toughness, stress corrosion) 

evaluation of the fully processed spin formed Al 2219 aft bulkhead pathfinder component was 

performed to screen property levels and to provide recommendations to the Orion Program 

Office regarding implementation of the spin forming fabrication method. 

The aft bulkhead was successfully spin formed, heat treated and sectioned for coupon testing. 

Dimensional analysis was conducted on the completed bulkhead and confirmed that final shape 

conformed to the manufacturing mandrel and any warping from solution heat treat, quench, or 

artificial aging was within acceptable manufacturing tolerances. An aft bulkhead coupon cut 

plan was created prior to spinning the bulkhead and was used as a basis for locating the coupons 

to be sectioned. Additional metallurgical and fractographic analyses were conducted to gain 

further insight into the effects of the processing and heat treat practice on the Al 2219 

microstructure and resultant mechanical properties. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

39 of 223

NESC Request No.: TI-13-00884 

8.1 Test and Analysis Procedures 

The spin formed aft bulkhead dome coupon testing was conducted by NASA LaRC, NASA 

MSFC, and NASA JSC. Qualifying tests were also conducted by LM-MAF, but are not included 

in this report due to schedule and mission requirements. Table 7.10-2 shows the test center and 

test type based upon coupon blank letter and number designations. Further details on the test and 

analysis procedures are presented in Sections 8.2 through 8.6. 

8.2 Metallurgical Analysis 

A strip-shaped blank was cut from the fully processed aft bulkhead for metallurgical analysis, 

spanning from the center of the aft bulkhead to near the rim along the 0° meridian line, noted as 

L7 in Figure 8.2-1. The blank dimensions were 4 inches in the transverse plate direction and 

62 inches along the meridian. Metallurgical samples were extracted at five locations along the 

strip as shown in Figure 8.2-2. Samples L7-1 through L7-5 were located at arc length distances 

from the pole that corresponded approximately to L/8 (8 inches), L/4 (16 inches), L/2 (27 

inches), 3L/4 (43 inches), and L (61 inches). Samples were examined using optical microscopy 

to evaluate variability in grain morphology and degree of recrystallization with distance from the 

pole and uniformity through the thickness at each location. 

The thickness of the L7 strip was measured at locations along the meridian line that 

corresponded to the locations of the UT measurements and laser scan analysis. Changes in 

thickness relative to the starting plate thickness were used to estimate the variation in 

deformation level throughout the aft bulkhead. Vernier calipers with ball end caps were used for 

these measurements. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

40 of 223

NESC Request No.: TI-13-00884 

Figure 8.2-1. Aft Bulkhead Cut Plan showing the Location of the Metallurgical Analysis Strip 

highlighted in Yellow 

Additional samples from the supplied starting plate were thermally processed at the timetemperature profiles associated with the various processing steps used in the production of the aft 

bulkhead (but without any spin forming deformation). Thermal exposures were performed 

during processing of the aft bulkhead in order to evaluate grain morphology evolution due to 

thermal processing alone. Samples were examined of the as-received plate (F temper), after the 

pre-spin forming anneal (O), after solution heat treat and water quench (T4), and after artificial 

aging (T6). The samples, shown in Figure 8.2-3, were examined using optical microscopy and 

compared with the aft bulkhead samples. 

Samples of the LT-S plane were polished through various grades of SiC paper and then colloidal 

diamond paste. Following polishing, the samples were etched with Keller’s reagent.
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

41 of 223

NESC Request No.: TI-13-00884 

Figure 8.2-2. Metallurgical Analysis Blank showing the Locations of Specimens L7-1 through L7-5 

Figure 8.2-3. Thermally Processed Test Blocks 

8.3 Tensile Test Procedures 

Coupon blanks L1-L6 from the aft bulkhead were provided to NASA LaRC for tensile testing. 

These blanks were obtained from the locations highlighted in yellow in the aft bulkhead cut plan 

(Figure 8.3-1) and coupon blank matrix (Table 8.3-1). Additional tensile tests were conducted 

on coupon blanks M1-M10 provided to NASA MSFC in support of SCC and fracture testing. 

These coupon blanks are also shown in the accompanying figure and table. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

42 of 223

NESC Request No.: TI-13-00884 

Figure 8.3-1. Aft Bulkhead Cut Plan Showing the Location of the Tensile Coupon Blanks 

highlighted in Yellow 

Table 8.3-1. Tensile Coupon Blank Size, Locations, and Orientations 

Long. Transv. Meridian Arc Length

Coupon Dimension, Dimension, Angle , from dome CL

Blank in. in. degrees in.

L1 14 12 351 54.63

L2 14 12 347 36.00

L3 14 12 330 16.13

L4 14 12 259 55.50

L5 14 12 263 35.88

L6 14 12 135 35.13

M1 14 12 9 54.63

M2 14 12 13 36.00

M3 14 12 30 16.13

M4 14 12 277 55.50

M5 14 12 281 35.88

M6 14 12 225 35.13

M7 14 12 90 12.00

M8 14 12 90 35.13

M9 14 12 90 56.25

M10 14 12 190 35.63

Coupon Blank Size Coupon Center Point
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

43 of 223

NESC Request No.: TI-13-00884 

Tensile testing of the spin formed aft bulkhead material was conducted in accordance with 

ASTM E8 (7). Room temperature tensile characterization was conducted in four grain 

orientations; L, LT, ST, and 45o

 to the ST (ST45). These grain orientations were with respect to 

the original plate rolling direction prior to spin forming. The ST45 orientation is not a typical 

test orientation for Al alloy plate, but was included for two reasons: (1) there may be regions of 

the aft bulkhead where service loads are aligned with the ST45 orientation, and (2) metallurgical 

theory suggests that for some alloys this may be the minimum strength orientation for plate. 

Two specimen designs were used; one for the L and LT orientations (Figure 8.3-2) and one for 

the ST and ST45 orientations (Figure 8.3-3). All specimens were machined from the coupon 

blanks such that the test section was located at the mid-plane thickness (t/2) of the coupon blank. 

Three replicate tests were conducted for each grain orientation as per the test matrix shown in 

Table 8.3-2. 

Tensile tests were conducted in a servo-hydraulic test machine at a displacement rate of 

0.01 in/min (ipm) to specimen failure using the test setup shown in Figure 8.3-4. Back-to-back 

extensometers with either a 1.000 in (L and LT specimens) or 0.500 in (ST and ST45 specimens) 

gauge length were used to measure specimen strain response. For tensile tests conducted at 

NASA MSFC, the displacement rate was 0.05 ipm and only a single 1.000/0.500 in extensometer 

was used. Ultimate tensile strength (UTS), 0.2% YS, and percent elongation (e) were 

determined for each test condition. The modulus of elasticity (E) was also calculated from the 

stress-strain plot and is shown in the results section as a reference value. Figure 8.3-5 shows a 

typical stress-strain curve for a tensile test. 

Figure 8.3-2. Round Subsize Tensile Specimen Design used for Testing in the L and LT 

Orientations 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

44 of 223

NESC Request No.: TI-13-00884 

Figure 8.3-3. Round Subsize Tensile Specimen Design used for Testing in the ST and ST45 

Orientations 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

45 of 223

NESC Request No.: TI-13-00884 

Table 8.3-2. Tensile Test Matrix for the Aft Bulkhead

Meridian Arc Length

Angle, from dome CL,

degrees in.

L T-L1-L-01 T-L1-L-02 T-L1-L-03

LT T-L1-LT-04 T-L1-LT-05 T-L1-LT-06

ST T-L1-ST-07 T-L1-ST-08 T-L1-ST-09

ST45 T-L1-ST45-10 T-L1-ST45-11 T-L1-ST45-12

L T-L2-L-13 T-L2-L-14 T-L2-L-15

LT T-L2-LT-16 T-L2-LT-17 T-L2-LT-18

ST T-L2-ST-19 T-L2-ST-20 T-L2-ST-21

ST45 T-L2-ST45-22 T-L2-ST45-23 T-L2-ST45-24

L T-L3-L-25 T-L3-L-26 T-L3-L-27

LT T-L3-LT-28 T-L3-LT-29 T-L3-LT-30

ST T-L3-ST-31 T-L3-ST-32 T-L3-ST-33

ST45 T-L3-ST45-34 T-L3-ST45-35 T-L3-ST45-36

L T-L4-L-37 T-L4-L-38 T-L4-L-39

LT T-L4-LT-40 T-L4-LT-41 T-L4-LT-42

ST T-L4-ST-43 T-L4-ST-44 T-L4-ST-45

ST45 T-L4-ST45-46 T-L4-ST45-47 T-L4-ST45-48

L T-L5-L-49 T-L5-L-50 T-L5-L-51

LT T-L5-LT-52 T-L5-LT-53 T-L5-LT-54

ST T-L5-ST-55 T-L5-ST-56 T-L5-ST-57

ST45 T-L5-ST45-58 T-L5-ST45-59 T-L5-ST45-60

L T-L6-L-61 T-L6-L-62 T-L6-L-63

LT T-L6-LT-64 T-L6-LT-65 T-L6-LT-66

ST T-L6-ST-67 T-L6-ST-68 T-L6-ST-69

ST45 T-L6-ST45-70 T-L6-ST45-71 T-L6-ST45-72

L CP-406-190 CP-406-192 CP-406-194

LT CP-406-195 CP-406-197 CP-406-199

ST CP-406-200 CP-406-202 CP-406-204

ST45 ---- ---- ----

L CP-406-205 CP-406-207 CP-406-209

LT CP-406-210 CP-406-212 CP-406-214

ST CP-406-215 CP-406-217 CP-406-219

ST45 ---- ---- ----

L CP-406-220 CP-406-222 CP-406-224

LT CP-406-225 CP-406-227 CP-406-229

ST CP-406-230 CP-406-232 CP-406-234

ST45 ---- ---- ----

L CP-406-235 CP-406-237 CP-406-239

LT CP-406-240 CP-406-242 CP-406-244

ST CP-406-245 CP-406-247 CP-406-249

ST45 ---- ---- ----

L CP-406-250 CP-406-252 CP-406-254

LT CP-406-255 CP-406-257 CP-406-259

ST CP-406-260 CP-406-262 CP-406-264

ST45 ---- ---- ----

L CP-406-265 CP-406-267 CP-406-269

LT CP-406-270 CP-406-272 CP-406-274

ST CP-406-275 CP-406-277 CP-406-279

ST45 ---- ---- ----

L ---- ---- ----

LT CP-406-1 CP-406-11 CP-406-21

ST CP-406-22 CP-406-32 CP-406-42

ST45 ---- ---- ----

L ---- ---- ----

LT CP-406-43 CP-406-53 CP-406-63

ST CP-406-64 CP-406-74 CP-406-84

ST45 ---- ---- ----

L ---- ---- ----

LT CP-406-85 CP-406-95 CP-406-105

ST CP-406-106 CP-406-116 CP-406-126

ST45 ---- ---- ----

L CP-406-127 CP-406-137 CP-406-147

LT CP-406-169 CP-406-179 CP-406-189

ST CP-406-148 CP-406-158 CP-406-168

ST45 ---- ---- ----

L6 135

L4 259

L5 263

L2 347

L3 330

L1 351

M3

M4

M5

M6

9

13

30

277

281

225

54.63

36.00

16.13

55.50

35.88

35.13

12.00

35.13

Coupon Blank

16.13

55.50

35.88

35.13

35.63

M2

90

90

90

190

Orient. Specimen Number

56.25

54.63

36.00

M7

M8

M9

M10

M1
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

46 of 223

NESC Request No.: TI-13-00884 

 

Figure 8.3-4. Tensile Test Load Stand, Specimen, and Instrumentation 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

47 of 223

NESC Request No.: TI-13-00884 

Figure 8.3-5. Typical Stress-Strain Curve for the Spin Formed Al 2219-T62 Aft Bulkhead Material 

in the L Orientation; Coupon Blank L2, Specimen T-L2-L-13 

8.4 Fracture Toughness Test Procedures 

Coupon blanks from the aft bulkhead were provided to NASA MSFC for fracture toughness 

testing. These blanks were identified as M1, M2, M3, M4, M5, and M6 and were obtained from 

the locations highlighted in yellow in the aft bulkhead cut plan (Figure 8.4-1) and coupon blank 

matrix (Table 8.4-1). 

0

10

20

30

40

50

60

-0.010 0.010 0.030 0.050 0.070 0.090 0.110 0.130

Stress (ksi)

Strain (in/in)
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

48 of 223

NESC Request No.: TI-13-00884 

Figure 8.4-1. Aft Bulkhead Cut Plan showing the Location of the Fracture Toughness Coupon 

Blanks highlighted in Yellow 

Table 8.4-1. Fracture toughness Coupon Blank Locations and Orientations 

Longitudinal Transverse Meridian Arc Length

Coupon Dimension, Dimension, Angle , from dome CL

Blank in. in. degrees in.

M1 14 12 9° 54-5/8

M2 14 12 13° 36

M3 14 12 30° 16-1/8

M4 14 12 277° 55-1/2

M5 14 12 281° 35-7/8

M6 14 12 225° 35-1/8

Coupon Blank Size Coupon Center Point

Fracture toughness testing of the spin formed aft bulkhead material was conducted in accordance 

with ASTM E1820 (8). Per this test method, the fracture toughness is quantified in terms of JIC, 

which is a measure of the fracture toughness of the material at the onset of stable crack 

extension. Fracture toughness characterization was conducted in three grain orientations, L-T, 

T-L, and S-T. The test orientation designation first identifies the loading direction and is 

followed by the crack growth orientation as they relate to the grain orientation of the material. 

The grain orientations are relative to the original grain orientation of the rolled plate prior to spin 

forming. Fracture toughness was measured using a compact tension (C(T)) specimen 

configuration. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

49 of 223

NESC Request No.: TI-13-00884 

Two specimen designs were used; one for the L-T and T-L orientations (Figure 8.4-2) and one 

for the S-T orientation (Figure 8.4-3). All specimens were machined from the coupon blanks 

such that the test section was located at the mid-plane thickness (t/2) of the coupon blank. Two 

replicate tests were conducted for each grain orientation as per the test matrix shown in 

Table 8.4-2. The test apparatus used for fracture toughness testing is shown in Figure 8.4-4. 

A

DETAIL A

2.500

2.000

1.000

1.00 u0.01

i 0.002 -Ai 0.002 -A0.800

0.750 u0.005

0.010 +0.000/ -0.004

C/L

0.200 u0.001

0.520

0.200

2x +0.005 / -0.000 O 0.500

0.100

30°

60°

0.800

i 0.002 -A3 xxx

3 xxx

5

4

6

5

1.195

2.400

Figure 8.4-2. JIC Fracture Toughness Specimen Design; L-T and T-L Orientations. 

Drawing No. S-295. All dimensions are in inches. 

i 0.002 -Ai 0.002 -A- C/L i 0.002 -A3 xxx

3 xxx

5

4

6

1.250

1.000

0.60

0.60

A

DETAIL A

2x +.005 / -0.000 O 0.250

0.010 +0.000 /-0.004

0.200

30°

0.100 0.145

0.500

60°

0.400

-A1

Figure 8.4-3. JIC Fracture Toughness Specimen Design; S-T Orientation. Drawing No. S-294. 

All dimensions are in inches. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

50 of 223

NESC Request No.: TI-13-00884 

Table 8.4-2. Fracture Test Matrix for the Aft Bulkhead 

Coupon

Blank

CP-406-191 M1 L-T

CP-406-193 M1 L-T

CP-406-196 M1 T-L

CP-406-198 M1 T-L

CP-406-201 M1 S-T

CP-406-203 M1 S-T

CP-406-206 M2 L-T

CP-406-208 M2 L-T

CP-406-211 M2 T-L

CP-406-213 M2 T-L

CP-406-216 M2 S-T

CP-406-218 M2 S-T

CP-406-221 M3 L-T

CP-406-223 M3 L-T

CP-406-226 M3 T-L

CP-406-228 M3 T-L

CP-406-231 M3 S-T

CP-406-233 M3 S-T

CP-406-236 M4 L-T

CP-406-238 M4 L-T

CP-406-241 M4 T-L

CP-406-243 M4 T-L

CP-406-246 M4 S-T

CP-406-248 M4 S-T

CP-406-251 M5 L-T

CP-406-253 M5 L-T

CP-406-256 M5 T-L

CP-406-258 M5 T-L

CP-406-261 M5 S-T

CP-406-263 M5 S-T

CP-406-266 M6 L-T

CP-406-268 M6 L-T

CP-406-271 M6 T-L

CP-406-273 M6 T-L

CP-406-276 M6 S-T

CP-406-278 M6 S-T

Specimen ID Orient.
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

51 of 223

NESC Request No.: TI-13-00884 

Figure 8.4-4. JIC Fracture Toughness Specimen and Test Apparatus 

Following machining, the C(T) specimen was cyclically loaded in tension to generate a fatigue 

precrack. The specimen was then tested per ASTM E1820 using the unloading compliance 

method for calculating crack length. A crack-mouth opening displacement gauge (COD) was 

used for measuring load-line displacement. The load and COD data was then used to generate a 

resistance curve, or R-curve, for each specimen that describes J (in-lbf/in2

) versus crack 

extension. An illustrative R-curve is shown in Figure 8.4-5. The critical J value, or JIC, is taken 

where the crack extension reaches 0.008 inches. This is considered the onset of tearing. Data 

beyond the critical value provides insight into the ability of the material to tear (crack extension) 

in a stable manner. Critical J values can be converted to K values (crack tip stress intensity, 

ksi√in) to support linear elastic fracture analysis. In the event the material displays unstable 

fracture, data from the ASTM E1820 test can be used to evaluate the critical crack tip stress 

intensity value (KIC). A typical R-curve for the spin formed aft bulkhead material is shown in 

Figure 8.4-6. Also, a typical post-test specimen fracture surface is shown in Figure 8.4-7. 

Significant features along the fracture surface are noted in Figure 8.4-7. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

52 of 223

NESC Request No.: TI-13-00884 

Figure 8.4-5. JIC Fracture Toughness R-Curve Plot 

Figure 8.4-6. Typical JIC Fracture Toughness R-Curve Plot 

Plot shown is for specimen CP-406-191 from coupon blank M1 in the L-T orientation. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

53 of 223

NESC Request No.: TI-13-00884 

Figure 8.4-7. Typical Cross-Sectional Fracture Surface of a JIC Fracture Toughness Specimen 

(specimen shown is CP-406-191 from coupon blank M1 in the L-T orientation) 

8.5 Stress Corrosion Test Procedures 

Coupon blanks M7, M8, M9, and M10 from the aft bulkhead were provided to NASA MSFC for 

SCC testing. These blanks were obtained from the locations highlighted in yellow in the aft 

bulkhead cut plan (Figure 8.5-1) and coupon blank matrix (Table 8.5-1). For each coupon blank, 

21 LT and 21 ST tension specimens were machined per the ASTM E8 small-size round tension 

test specimen design shown in Figure 8.5-2. In addition, 21 L tension specimens were machined 

from coupon blank M10. These specimen orientations were with respect to the original plate 

rolling direction. The coupon blank cut plans for these tension specimens are shown in Figures 

8.5-3 through 8.5-6. Three specimens from each set of 21 were used to obtain baseline tensile 

data to establish applied stress levels for SCC testing; the remaining 18 were used for SCC 

testing. Specimen design and test procedures for these baseline tensile tests are discussed in 

Section 8.3. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

54 of 223

NESC Request No.: TI-13-00884 

Figure 8.5-1. Aft Bulkhead Cut Plan showing the Location of the SCC Coupon Blanks highlighted 

in Yellow 

Table 8.5-1. SCC Coupon Blank Locations and Orientations 

Coupon 

Blank 

Longitudinal 

Dimension, 

in. 

Transverse 

Dimension, 

in. 

Meridian 

Angle, 

degrees 

Center Point 

Arc Length, 

in. 

M7 14 12 90° 12.00 

M8 14 12 90° 35.13 

M9 14 12 90° 56.25 

M10 14 12 190° 35.63 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

55 of 223

NESC Request No.: TI-13-00884 

NOTES: 

1. Tolerances: ± 0.005 inch, except otherwise specified. 

2. Surface finish: 16√ for the reduced section, 32√ for the rest.

3. Thread dimensions must be as specified. Measurement by fabricator is mandatory. 

4. No undercutting of radii permitted. 

5. Gage section to be concentric with axis within 0.002 inch TIR and parallel. 

6. No file marks or nicks permitted within gage section. 

7. Center-drilling permissible (both ends). May use a #1 size max. Chamfer diameter not to 

exceed 0.100 inch. 

8. Break sharp edges. 

9. The reduced section may have a gradual taper from the ends toward the center with the ends 

not more than 0.005 inch larger diameter than the center. 

Figure 8.5-2. Round Sub-Size Tensile Specimen Design used for SCC Testing 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

56 of 223

NESC Request No.: TI-13-00884 

Figure 8.5-3. Cut Plan for Machining SCC Specimens from Coupon Blank M7 

(specimens CP-406-1 through CP-406-42) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

57 of 223

NESC Request No.: TI-13-00884 

Figure 8.5-4. Cut Plan for Machining SCC Specimens from Coupon Blank M8 

(specimens CP-406-43 through CP-406-84) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

58 of 223

NESC Request No.: TI-13-00884 

Note: This sequence starts with CP-406-85, not CP-406-83 as stated in the drawing, or CP-406-

53 as stated in note 4. 

Figure 8.5-5. Cut Plan for Machining SCC Specimens from Coupon Blank M9 

(specimens CP-406-85 through CP-406-126) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

59 of 223

NESC Request No.: TI-13-00884 

Note: The sequence for the ST specimens starts with CP-406-148 through CP-406-168. A set of 21 longitudinal 

specimens was also fabricated from this coupon blank, and that sequence starts with CP-406-127 through CP-406-

147. The sequence for the LT specimens is as shown in the table (CP-406-169 through CP-406-189. 

Figure 8.5-6. Cut Plan for Machining SCC Specimens from Coupon blank M10 

(specimens CP-406-127 through CP-406-189) 

The SCC testing, analysis, and rating were performed in accordance with MSFC-STD-3029, 

which provides guidelines for the selection of metallic materials for stress corrosion resistance 

and is the standard for Space Flight Hardware. The SCC specimens were tested using the direct 

tension loading method as described in ASTM G49 (9). The LT and ST SCC specimens were 

stressed in tension to 0, 50-, 75-, and 90% of the average YS measured from baseline tensile tests 

of the aft bulkhead and subjected to alternate immersion exposure in a 3.5% NaCl solution for 

test durations of 30 and 90 days per ASTM G44 (10). The L SCC specimens from coupon blank 

M10 were also stressed in tension to 0-, 50-, 75-, and 90% of the YS, but were subjected to salt 

spray exposure for test durations of 30 and 90 days per ASTM B117 (11). Three replicate 

specimens were tested for each stress level, test duration, and exposure environment per the SCC 

test matrices, as shown in Table 8.5-2- Table 8.5-5. Figure 8.5-7 shows the stressing device, 

extensometer, stressing frames, and representative SCC specimens. The alternate immersion test 

apparatus and salt spray chamber are shown in Figure 8.5-8. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

60 of 223

NESC Request No.: TI-13-00884 

Table 8.5-2. 30-Day SCC Test Matrix for the Spin Formed Aft Bulkhead Al 2219-T62 Material 

Test Environment: 3.5% NaCl alternate immersion per ASTM G44 

Coupon

Blank 

Meridian

Angle Orientation 

Stress 

Level 

% YS 

Number of 

Replicates 

M7 90° 

LT 

0 3 

50 3 

75 3 

90 3 

ST 

0 3 

50 3 

75 3 

90 3 

M8 90° 

LT 

0 3 

50 3 

75 3 

90 3 

ST 

0 3 

50 3 

75 3 

90 3 

M9 90° 

LT 

0 3 

50 3 

75 3 

90 3 

ST 

0 3 

50 3 

75 3 

90 3 

M10 190° 

LT 

0 3 

50 3 

75 3 

90 3 

ST 

0 3 

50 3 

75 3 

90 3 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

61 of 223

NESC Request No.: TI-13-00884 

Table 8.5-3. 90-Day SCC Test Matrix for the Spin Formed Aft Bulkhead Al 2219-T62 Material. 

Test Environment: 3.5% NaCl alternate immersion per ASTM G44 

Coupon 

Blank 

Meridian 

Angle Orientation Stress Level % YS 

Number of 

Replicates 

M7 90° 

LT 0 3 

75 3 

ST 0 3 

75 3 

M8 90° 

LT 0 3 

75 3 

ST 0 3 

75 3 

M9 90° 

LT 0 3 

75 3 

ST 0 3 

75 3 

M10 190°

LT 0 3 

75 3 

ST 0 3 

75 3 

Table 8.5-4. 30-Day SCC Test Matrix for the Spin Formed Aft Bulkhead Al 2219-T62 Material 

Test Environment: 5% salt spray per ASTM B117 

Coupon 

Blank 

Meridian 

Angle Orientation Stress Level % YS 

Number of 

Replicates 

M10 190° L 

0 3 

75 3 

Table 8.5-5. 90-Day SCC Test Matrix for the Spin Formed Aft Bulkhead Al 2219-T62 Material 

Test Environment: 5% salt spray per ASTM B117 

Coupon 

Blank 

Meridian 

Angle Orientation Stress Level % YS 

Number of 

Replicates 

M10 190° L 

0 3 

50 3 

75 3 

90 3 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

62 of 223

NESC Request No.: TI-13-00884 

 (a) (b) 

Figure 8.5-7. (a) Stressing Device and (b) Representative Stressed Specimens and Stressing Frames 

 (a) (b) 

Figure 8.5-8. (a) Alternate Immersion Test Apparatus and (b) Salt Spray Chamber 

Specimens were considered to have failed during the SCC test if one or more of the specimens 

fractured during exposure or exhibited cracking during post-exposure visual examination. If any 

failures occurred, then that specimen was sectioned and the morphology of the fracture 

examined. If no failures occurred for a given test condition, then one specimen from the set was 

subjected to metallographic examination while the remaining two specimens were tensile tested 

to failure to determine residual tensile strength. Two measures were used to evaluate the residual 

tensile strength of the surviving specimens: the percent tensile strength retained, which 

compares the residual tensile strength of the exposed specimens to typical tensile properties of 

unexposed specimens; and the residual strength ratio, which compares the residual tensile 

strength of specimens exposed with and without an applied stress. 

The percent tensile strength retained provides a measure of the residual load carrying ability of 

the specimen as compared to unexposed specimens and is an indication of the reduction in 

specimen cross-sectional area, not a change in strength of the material. Loss in cross-sectional 

area can be due to general corrosion, pitting, and stress corrosion. Metallurgical examination is 

required to confirm the type of corrosion. For the specimens tested with an applied stress, the 

reduction in tensile strength is the combined effect of stress and the corrosive environment. For 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

63 of 223

NESC Request No.: TI-13-00884 

the specimens tested with no applied stress the reduction is the effect of the corrosive 

environment only. The percent tensile strength retained for each exposed specimen was 

calculated as follows: 

 Percent Tensile Strength Retained = (UTSf/UTSi) x 100 

 where: 

UTSf = Residual strength of the exposed specimen (failure load/original specimen crosssectional area) 

UTSi = Average ultimate tensile strength for the unexposed specimens. 

The residual strength ratio provides a more direct indication of the effect of applied stress during 

exposure and therefore a method to separate the effects of general corrosion and pitting from 

stress corrosion. The UTSS and UTS0 are calculated based on original specimen cross-sectional 

area, and provide an indication of the loss in area due to stress corrosion and general corrosion, 

respectively. For this study, specimens with residual strength ratios of less than 0.75 were 

considered failures. The residual strength ratio for each specimen that was exposed with an 

applied stress was calculated as follows: 

Residual Strength Ratio = UTSs/UTS0

where: 

UTSs = Residual strength of stressed and exposed specimen 

UTS0 = Averaged residual strength of non-stressed and exposed specimens 

At the end of the test, the pass/fail data obtained was used to assign a stress corrosion 

susceptibility rating for the material based on the requirements in MSFC-STD-3029A (12). They 

are as follows: 

Table I Requirements 

Alloys, tempers, and weldments in Table I are considered highly resistant to SCC in 3.5% NaCl 

alternate immersion or 5% salt spray. An alloy or weldment can be added to this table if no 

stress corrosion failures occur on specimens stressed to 75% of the YS within 30 days of 

exposure. 

Table II Requirements 

Alloys, tempers, and weldments in Table II are considered moderately resistant to SCC in 3.5% 

NaCl alternate immersion or 5% salt spray. An alloy or weldment is added to this table if no 

stress corrosion failures occur on specimens stressed to 50% of the YS within 30 days of 

exposure. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

64 of 223

NESC Request No.: TI-13-00884 

Table III Requirements 

Alloys, tempers, and weldments in Table III are considered to have low resistance to SCC in 

3.5% NaCl alternate immersion or 5% salt spray. They are placed in this table if stress corrosion 

failures occur on specimens stressed to 50% of the YS within 30 days of exposure. 

8.6 Seacoast Exposure SCC Test Plan 

While the 3.5% NaCl solution alternate immersion test provides a comprehensive screening 

method for accelerated stress corrosion testing of high-strength Al alloy product forms, a 

disadvantage of the test is that severe pitting may develop in the specimens (13). Such pitting in 

tension specimens with relatively small cross-section can markedly reduce the effective crosssectional area and produce a net section stress greater than the nominal gross section stress, 

resulting in either: (1) fracture by mechanical overload of a material that is not susceptible to 

SCC; or (2) SCC of a material at an actual stress higher than the intended nominal test stress. 

The occurrence of either of these phenomena might then interfere with a valid evaluation of 

materials with relatively high resistance to stress corrosion. As a result, seacoast exposure SCC 

testing was proposed as a complementary screening test in this project. Seacoast exposure SCC 

testing, which is performed in a natural outdoor environment and requires longer test durations 

than the standard accelerated corrosion tests performed in a laboratory, is more representative of 

the intended service environment 

Three coupon blanks from the aft bulkhead were provided to NASA JSC for seacoast exposure 

SCC testing at NASA KSC. These blanks were identified as J1, J2, and J3 and were obtained 

from the locations highlighted in yellow in the aft bulkhead cut plan (Figure 8.6-1) and coupon 

blank matrix (Table 8.6-1). For each coupon blank, 9 short transverse (ST) tension specimens 

were machined per the ASTM E8 small-size round tension test specimen design (Figure 8.6-2). 

This specimen orientation is with respect to the original plate rolling direction. Specimens were 

machined such that the gage section was located at the mid-plane thickness (t/2) of the coupon 

blank. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

65 of 223

NESC Request No.: TI-13-00884 

Figure 8.6-1. Aft Bulkhead Cut Plan showing the Location of the Seacoast Exposure SCC Coupon 

Blanks highlighted in Yellow 

Table 8.6-1. Seacoast Exposure SCC Coupon Blank Locations and Orientations.

Longitudinal Transverse Meridian Arc Length

Coupon Dimension, Dimension, Angle , from dome CL

Blank in. in. degrees in.

J1 14 12 180° 12

J2 14 12 170° 35-5/8

J3 14 12 180° 55-5/8

Coupon Blank Size Coupon Center Point

NOTE: 

Prior to the start of the seacoast exposure SCC tests, the initial laboratory alternate immersion 

SCC tests results became available. Based upon the 30-day alternate immersion exposure in 

3.5% NaCl test results (Section 10.4.1.1), the accelerated test condition provides adequate 

screening methodology for SCC. Longer test durations of 90 days, however, did lead to severe 

general corrosion and pitting (Section 10.4.1.2). Consequently, specimens scheduled for 

seacoast exposure testing in this project were diverted to laboratory alternate immersion testing 

at MSFC to generate SCC data on more locations in the aft bulkhead and to confirm initial test 

results. The NESC team recommends that Orion conduct seacoast exposure SCC testing of the 

first-article aft bulkhead in order to characterize the corrosion performance in the service 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

66 of 223

NESC Request No.: TI-13-00884 

environment. The following test plans are provided as a guide for the Orion Program if they 

choose to conduct these tests. 

The seacoast exposure SCC specimens should be tested using the direct tension loading method 

as described in ASTM G49. The specimens should be stressed in tension to 0-, 75-, and 90% of 

the YS and will be subjected to seacoast exposure for durations of up to 3 years as per ASTM 

G44. Table 8.6-2 shows a proposed seacoast exposure SCC test matrix. Specimens should be 

tested in triplicate for each test condition. 

Table 8.6-2. Test Matrix for the Seacoast Exposure SCC Tests 

9.0 LM Test Plan 

This is a high-level summary of the LM test plan in support of the LM Orion Program. This 

information is provided for completeness and is intended to indicate the overall scope of the 

activities. Due to proprietary considerations, results from this work will not be published in this 

or addendum NESC reports. 

The LM test plan focused on two activities; FSW schedule development and complementary 

mechanical property, and structural subcomponent testing. Further details are provided in 

Sections 9.1 and 9.2 

9.1 Self-Reacting FSW and Friction Pull Plug Weld (FPPW) Development 

Coupon blanks from the aft bulkhead were provided to LM-MAF for SR-FSW and FPPW 

schedule development. These blanks were identified as MF1, MF2, MF3, MF4, MF5, MF6, 

MF7, and MF8 and were obtained from the arc-shaped segments located at the rim of the aft 

bulkhead as shown in the aft bulkhead cut plan (Figure 9.1-1) and coupon blank matrix 

(Table 9.1-1). 

Bulkhead Coupon Meridian Stress #

Location Blank Angle Orient. Level Replicates

0% YS 3

75% YS 3

90% YS 3

0% YS 3

75% YS 3

90% YS 3

0% YS 3

75% YS 3

90% YS 3

Rim J3 180° ST

180° ST

Membrane J2 180° ST

Pole J1
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

67 of 223

NESC Request No.: TI-13-00884 

Figure 9.1-1. Aft Bulkhead Cut Plan showing the Location of the FSW and FPPW Schedule 

Development Coupon Blanks

Table 9.1-1. FSW and FPPW Schedule Development Coupon Blank Locations and Orientations

Longitudinal Transverse Meridian Arc Length

Coupon Dimension, Dimension, Angle , from dome CL

Blank in. in. degrees in.

MF1 N/A N/A 31° 56-3/4

MF2 N/A N/A 64° 56-3/4

MF3 N/A N/A 116° 56-3/4

MF4 N/A N/A 154° 56-3/4

MF5 N/A N/A 206° 56-3/4

MF6 N/A N/A 240° 56-3/4

MF7 N/A N/A 296° 56-3/4

MF8 N/A N/A 329° 56-3/4

Coupon Blank Size Coupon Center Point

The LM Orion Program was provided with spin formed Al 2219-T62 aft bulkhead material to 

develop nominal SR-FSW and FPPW weld schedules. The development will be focused on 

schedules for the Al 2219-T6 plate and Al 2219-T8 forging weld combination that will be 

utilized on the Orion CM. 

The SR-FSW development will generally follow three phases of development. The first phase 

will follow a design of experiment to evaluate the weldability of the material combination. 

Evaluation will consist of non-destructive phased array ultrasonic testing (PAUT) inspection, 

tensile testing, and metallography. Emphasis will be placed on identifying load characteristics 

and identifying potential nominal weld schedules that show a strength insensitivity to load. The 

second phase will be a verification step, aimed at characterizing the available operating load 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

68 of 223

NESC Request No.: TI-13-00884 

ranges and down-selecting a final nominal weld schedule. The final phase will involve sensitivity 

testing were the selected nominal schedule will be exposed to production-related variables. 

These verification tests will include, but not be limited to, joint fit-up, tacking, off-set, and clean 

time. The end of the development cycle will produce a weld schedule that the Orion Program 

will feel confident about going forward into the production pathfinder activity. The pathfinder 

activity will be the final step that certifies the weld schedule for use on production flight articles. 

The FPPW development will follow a cycle similar to the SR-FSW cycle described above. The 

initial phase FPPW will be geared towards establishing the boundaries of the FPPW weldable 

space. These welds will then be evaluated using penetrant and ultrasonic inspection, tensile tests 

for ultimate strength, YS, elongation, and metallography. The results of the initial welding will 

be characterized in an attempt to understand the driving factors of FPPW and determine potential 

nominal FPPW schedules. The second phase will take the selected nominal schedules and run a 

series of verification tests to characterize the repeatability of the weld schedules performance. 

The final phase will evaluate sensitivity impacts. Again, these verification tests will include, but 

not be limited to joint fit-up, alignment, and cleaning. The end of the development cycle will 

produce a weld schedule that the LM Orion Program feels confident about going forward into the 

production pathfinder activity. The pathfinder activity will be the final step that certifies the weld 

schedule for use on production flight articles. 

9.2 Mechanical Property and Structural Subcomponent Testing 

Coupon blanks from the aft bulkhead were provided to LM-MAF for mechanical property testing 

in support of the Orion Program. These blanks were identified as MF9, MF10, MF11, MF12, 

and MF13 and were obtained from the locations highlighted in yellow in the aft bulkhead cut 

plan (Figure 9.2-1) and coupon blank matrix (Table 9.2-1). 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

69 of 223

NESC Request No.: TI-13-00884 

Figure 9.2-1. Aft Bulkhead Cut Plan showing the Location of the Supplemental Mechanical 

Property Test Coupon Blanks highlighted in Yellow 

Table 9.2-1. LM Mechanical Property Test Coupon Blank Locations and Orientations 

Longitudinal Transverse Meridian Arc Length

Coupon Dimension, Dimension, Angle , from dome CL

Blank in. in. degrees in.

MF9 14 12 45° 35-1/8

MF10 14 12 114° 40-3/8

MF11 14 12 270° 12

MF12 14 12 328° 40

MF13 14 12 304° 39-7/8

Coupon Blank Size Coupon Center Point

The testing program at MAF is designed to complement the mechanical property test data 

(tensile, fracture, and SCC) being generated by the NESC team and provide additional 

supporting data to aid the Orion Program in the design of the aft bulkhead. The first objective of 

these mechanical property tests is to characterize the fatigue properties of the spin formed Al 

2219-T62 aft bulkhead material and compare it to existing reference data for both Al 2219-T6 

and –T8 product forms. This fatigue testing will include surface flaw testing to a leak condition, 

using specimens that will be machined to the minimum membrane thickness and crack growth 

testing in the ST orientation. The second objective is to characterize the aft bulkhead material 

with bearing and insert pull tests. This testing will utilize special machined specimens that are 

representative of hardware attachment methods used on the Orion aft bulkhead. 

After completion of the NESC test program, the skeletal remains of the spin formed aft bulkhead 

(Figure 7.10-2) were shipped to LM-MAF for further testing. Planned activities include 

structural subcomponent testing in which different configurations of the backbone-to-aft 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

70 of 223

NESC Request No.: TI-13-00884 

bulkhead joint will be tested to simulate the CM internal pressure load (Figure 9.2-2). The goals 

of these tests are to demonstrate structural performance of the aft bulkhead in the ST direction 

and to verify bolt and splice plate strength. 

Figure 9.2-2. Schematic showing the Simulated Location for Backbone Panel 6 Connection to Aft 

Bulkhead Joint 

10.0 Results and Discussion 

10.1 Metallurgical Analysis 

10.1.1 Thickness Measurements 

The thickness of the L7 coupon blank was measured at locations along the meridian line that 

corresponded to the locations of the UT measurements and laser scan analysis. Vernier calipers 

with ball end caps were used for these measurements and an effort was made to make 

measurements at the base of the surface scallops. The measurements are summarized in 

Table 10.1-1 and compared with the UT and laser scan measurements in Figure 10.1-1. The 

maximum thickness occurred at a distance of 4 inches from the pole, the minimum thickness at 

52 inches, and the maximum reduction in thickness was 0.12 inches, values that are fairly 

consistent with the UT and laser scan results. Thickness measurements from all three sources 

indicate a 4 to 5% reduction in thickness. Also consistent with the UT and laser scan data, the 

thickness measured on coupon blank L7 indicates thinning from pole to rim for approximately 50 

inches and then thickening to the rim. The L7 thickness profile in Figure 10.1-1 shows minimal 

fluctuations except toward the rim. 

The deformation induced during spin forming is complex and non-uniform. Thickness reduction 

is a simplified metric used in this analysis to evaluate the variation over the acreage of the aft 

bulkhead. During convex spin forming there is generally no deliberate reduction in wall 

thickness as the material is shaped over the mandrel (2). During forming the blank diameter is 

reduced as material is pushed onto the mandrel, particularly near the rim, consequently the 

material experiences circumferential compressive stress superimposed on radial tensile stress, 

12”

14”
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

71 of 223

NESC Request No.: TI-13-00884 

which combine to result in nearly constant wall thickness. So many process parameters affect 

material response during spin forming that modeling the process has been unsuccessful. The 

industrial success of spin forming is based on extensive experience at the vendors. 

Table 10.1-1. Thickness Measurements of Coupon Blank L7 at Distances from the Pole 

Thickness Measurements of Coupon Blank L7 

Distance from Pole 

(in) Thickness (in) 

4 2.319 

12 2.318 

20 2.290 

24 2.287 

32 2.245 

36 2.253 

40 2.275 

48 2.221 

52 2.204 

56 2.270 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

72 of 223

NESC Request No.: TI-13-00884 

Figure 10.1-1. Thickness Profile of Coupon Blank L7 Compared with the UT and Laser Scan Data 

10.1.2 Microstructural Analysis 

Through-thickness montages shown in Figure 10.1-2 for samples L7-1 through L7-5 illustrate 

the variability in grain morphology with both through-thickness location and distance from the 

pole of the aft bulkhead. The blue lines denote through-thickness locations (t = thickness) that 

were examined at higher magnification and which are shown in Figure 10.1-3. Specimen L7-1 is 

located near the pole just inside the innermost forming tool contact area and consequently 

represents a region that was not deformed by spin forming. The thickness profile of coupon 

blank L7 indicates that the forming blank was thinned by about 4-5% during spin forming to 

create the aft bulkhead shape, with the thickness decreasing from pole to a minimum near the rim 

at a distance of approximately 50 inches from the pole and then increasing in thickness at the 

rim. 

The through-thickness micrographs in Figure 10.1-2 show that as deformation increases, the 

microstructure changes from a uniform small grain size (L7-1) to a banded microstructure that 

2.20

2.22

2.24

2.26

2.28

2.30

2.32

2.34

0 10 20 30 40 50 60 70

Thickness, in

Distance from Pole, in

Aft Bulkhead Thickness Profile

Average UT Measurement

Laser Scan

L7
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

73 of 223

NESC Request No.: TI-13-00884 

exhibits regions of larger grain size, most likely due to strain induced recrystallization, primarily 

towards the OML surface where the forming tool contacts the plate. Notably larger grain size is 

observed between 3t/4 and 7t/8 starting with L7-2 and more pronounced in L7-3 and L7-4. 

Macroscopic deformation bands are observed near the OML, particularly in samples L7-3, L7-4, 

and L7-5. 

Figure 10.1-2. Through-thickness Microstructures of the Aft Bulkhead at Locations Along the 

0° Meridian 

Higher magnification micrographs of each through-thickness position for meridian locations 

L7-1 through L7-5 are summarized in Figure 10.1-3(a-e). All samples exhibit grains slightly 

elongated in the LT direction. At the L7-1 location ((Figure 10.1-3(a)), no deformation) the 

grain size and morphology are uniform from IML to OML. All through-thickness positions at 

L7-1 exhibit precipitation on deformation bands, particularly from 3t/8 to 5t/8. Sections L7-2 

through L7-5 exhibit strain induced recrystallization, biased towards the OML and extending 

from the OML towards the mid-thickness. In sections L7-4 and L7-5, recrystallization occurs 

from the OML to 3t/8. All through-thickness positions exhibit precipitation on deformation 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

74 of 223

NESC Request No.: TI-13-00884 

bands, more heavily in the unrecrystallized regions. Aligned precipitation in the recrystallized 

regions may indicate that the prior deformation history associated with both plate rolling and 

spin forming is not completely erased during SHT. Alternatively, the alignment may indicate 

precipitation on slip planes (14), (15), (16). 

(a) Microstructure at L7-1 (L/8, 8 inches from the pole) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

75 of 223

NESC Request No.: TI-13-00884 

(b) Microstructure at L7-2 (L/4, 16 inches from the pole) 

(c) Microstructure at L7-3 (L/2, 27 inches from the pole) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

76 of 223

NESC Request No.: TI-13-00884 

(d) Microstructure at L7-4 (3L/4, 43 inches from the pole) 

(e) Microstructure at L7-5 (L, 61 inches from the pole) 

Figure 10.1-3. Microstructure at the IML, t/8, t/4, 3t/8, t/2, 5t/8, 3t/4, 7t/8, and OML ThroughThickness Positions for (a) L7-1, (b) L7-2, (c) L7-3, (d) L7-4, and (e) L7-5 Locations along the 0° 

Meridian 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

77 of 223

NESC Request No.: TI-13-00884 

Through-thickness micrographs of the thermally processed blocks shown in Figure 10.1-4 for asreceived plate (F), after the pre-spin forming anneal (O), after SHT (T4), and after aging (T6). In 

comparison with the F and O tempers, the T4 and T6 blocks exhibit larger grain size indicative 

of recrystallization during SHT. In contrast to the fully processed spin formed material shown in 

Figure 10.1-2 and Figure 10.1-3, the microstructure of the T4 and T6 thermally processed blocks 

shown in Figures 10.1-5 and 10.1-6 exhibit uniform microstructures with smaller grain sizes 

indicating that spin forming deformation promotes larger recrystallized grain size. Tracking of 

the OML and IML surfaces was maintained during spin forming and subsequent thermal 

processing of the aft bulkhead forming blank for direct comparison with the thermally processed 

test blocks. Macroscopically, the microstructure of the T6 processed test block is similar to the 

L7-1 sample from the aft bulkhead (Figure 10.1-2). Higher magnification micrographs of the 

thickness positions noted in Figure 10.1-4 for the T4 and T6 conditions are shown in Figure 

10.1-5. Both conditions exhibit uniform through-thickness microstructure with slightly smaller 

grain sizes at the OML and IML surfaces. The grain size and morphology in both T4 and T6 

conditions are similar to that observed in section L7-1 (Figure 10.1-2(a)) from the aft bulkhead, 

which did not experience deformation. The T6 test block exhibits precipitation on residual 

deformation bands similar to those observed in section L7-1, at positions from t/2 to 7t/8, and are 

similarly much less apparent at the OML and IML. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

78 of 223

NESC Request No.: TI-13-00884 

Figure 10.1-4. Through-Thickness Microstructures of the Thermally Processed Test Blocks 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

79 of 223

NESC Request No.: TI-13-00884 

(a) Through-thickness microstructure of the T4 thermally processed test block. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

80 of 223

NESC Request No.: TI-13-00884 

(b) Through-thickness microstructure of the T6 thermally processed test block. 

Figure 10.1-5. Microstructure at the IML, t/2, 5t/8, 3t/4, 7t/8, and OML Through-Thickness 

Positions for the (a) T4 and (b) T6 Thermally Processed Test Blocks 

Microstructures of the aft bulkhead sections L7-1 through L7-5 are compared in Figure 10.1-6 

with the T6 thermally processed test block at the through-thickness locations IML, t/2, 5t/8, 3t/4, 

7t/8, and OML. The grain size and morphology are similar in all samples at the IML 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

81 of 223

NESC Request No.: TI-13-00884 

(Figure 10.1-6(a)), and also represent the smallest and most equiaxed grain structure at all 

through-thickness locations. The post-recrystallization grain size varies throughout the L7 

meridian locations and through-thickness positions, with larger grain sizes associated with likely 

regions of higher deformation. Evidence of precipitation on prior deformation bands is noted 

throughout all samples. At t/2 and 5t/8, the grain size is largest in the L7-4 and L7-5 locations, 

with L7-1 through L7-3 locations exhibiting similar grain size to that in the T6 test block. At 

3t/4, the grain size is similar and notably larger in L7-2 through L7-5 than in L7-1 and T6. At 

7t/8 the grain size is largest in L7-3 and L7-4. At the OML, the grain size is notably larger in 

L7-3 through L7-5 than L7-1 through L7-2 and T6. These variations in grain size in the aft 

bulkhead sections compared with T6 are indicative of the complex and varied deformation levels 

associated with the spin forming process, particularly when combined with the plate rolling 

history and post-forming heat treatment. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

82 of 223

NESC Request No.: TI-13-00884 

Microstructure of aft bulkhead locations L7-1 through L7-5 compared with the T6 

thermally processed test block at (a) IML 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

83 of 223

NESC Request No.: TI-13-00884 

Microstructure of aft bulkhead locations L7-1 through L7-5 compared with the T6 

thermally processed test block at (b) t/2. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

84 of 223

NESC Request No.: TI-13-00884 

Microstructure of aft bulkhead locations L7-1 through L7-5 compared with the T6 

thermally processed test block at (c) 5t/8.
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

85 of 223

NESC Request No.: TI-13-00884 

Microstructure of aft bulkhead locations L7-1 through L7-5 compared with the T6 

thermally processed test block at (d) 3t/4. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

86 of 223

NESC Request No.: TI-13-00884 

Microstructure of aft bulkhead locations L7-1 through L7-5 compared with the T6 

thermally processed test block at (e) 7t/8. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

87 of 223

NESC Request No.: TI-13-00884 

Microstructure of aft bulkhead locations L7-1 through L7-5 compared with the T6 

thermally processed test block at (f) OML. 

Figure 10.1-6. Microstructure of Aft Bulkhead Locations L7-1 through L7-5 Compared with the 

T6 Thermally Processed Test Blocks at Through-Thickness Positions (a) IML, (b) t/2, (c) 5t/8, (d) 

3t/4, (e) 7t/8, and (f) OML 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

88 of 223

NESC Request No.: TI-13-00884 

Various options exist for altering the recrystallization kinetics during spin forming and heat 

treatment and the resulting recrystallized grain size. These include changing the spin forming 

temperature, incorporating a recovery anneal, or changing the SHT temperature. A higher spin 

forming temperature may result in lower retained deformation (reduce stored energy) in the 

material and thus reduce the driving force for recrystallization during SHT, whereas a lower 

forming temperature would increase the stored energy and provide more nucleation sites for 

recrystallization during SHT, which would result in lower overall grain size due to grain 

boundary impingement. While the change in forming parameters may result in a change in the 

recrystallization kinetics, they represent a major shift in the established practice for Spincraft and 

would require substantial empirical development and validation. 

Lower SHT temperatures following spin forming would reduce the overall recrystallized grain 

size due to lower thermal energy for grain growth. Since the objective of the SHT is to put as 

much solute (alloying additions) as possible into solid solution in order to obtain optimum 

properties after the final heat treatment process step (aging), adopting a SHT temperature below 

this range may limit the peak strength that can be achieved during aging. However, depending 

on service requirements, sufficient strength may be developed. Extending SHT time may 

provide some property recovery. 

A more viable option may be to incorporate a recovery anneal during heat up to the SHT 

temperature to reduce the driving force for recrystallization. This recovery anneal can be readily 

incorporated into their standard SHT cycle. 

Tensile, fracture, and stress corrosion specimens extracted from the aft bulkhead were located at 

t/2. The microstructure at t/2 for the aft bulkhead locations L7-1 through L7-5 and the T6 test 

block shown in Figure 10.1-6(b) exhibit the greatest similarity in grain size and morphology and 

extent of precipitation on prior deformation bands. Additional specimen testing will be needed 

to evaluate the effect of the variable microstructures at other through-thickness positions, 

particularly those biased toward the OML. 

F-1. The aft bulkhead microstructure varies both through-thickness and along the meridian arc 

length positions, with larger grain sizes associated with likely regions of higher 

deformation. 

x Grain size was larger toward the rim and toward the OML surface, likely 

associated with the combined stresses necessary to shape the material to fit the 

mandrel. 

x These variations in grain size are indicative of the complex and varied 

deformation levels associated with the spin forming process, particularly when 

combined with the plate rolling history and post-forming heat treatment. 

10.2 Tensile Test Results 

Figure 10.2-1 shows the aft bulkhead cut plan with the location of coupon blanks from which 

tensile specimens were excised for mechanical property testing highlighted in yellow. Coupon 

blanks L1-L6 were tensile tested at LaRC while coupon blanks M1-M10 were tested at MSFC. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

89 of 223

NESC Request No.: TI-13-00884 

Table 10.2-1 shows the size and location of these coupon blanks with respect to the original plate 

rolling direction and distance from the aft bulkhead pole to the coupon blank center point. These 

coupon blank locations were designed to determine uniformity of tensile properties throughout 

the aft bulkhead and were evaluated along selected meridian and circumferential lines. 

An additional goal of these tests was to determine how these properties compare to wrought plate 

in the T6 and T8 tempers and to other fabricated product forms in the T6 temper. These results 

will assist the Orion designers in assessing the attributes of the spin form fabrication process for 

the aft bulkhead and identify any deficiencies or “show stoppers” associated with this fabrication 

process. 

Figure 10.2-1. Aft Bulkhead Cut Plan showing the Location of the tensile Coupon Blanks 

highlighted in Yellow 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

90 of 223

NESC Request No.: TI-13-00884 

Table 10.2-1. Tensile Coupon Blank Locations and Orientations 

Longitudinal Transverse Meridian Arc Length

Coupon Dimension, Dimension, Angle , from dome CL

Blank in. in. degrees in.

L1 14 12 351° 54-5/8

L2 14 12 347° 36

L3 14 12 330° 16-1/8

L4 14 12 259° 55-1/2

L5 14 12 263° 35-7/8

L6 14 12 135° 35-1/8

M1 14 12 9° 54-5/8

M2 14 12 13° 36

M3 14 12 30° 16-1/8

M4 14 12 277° 55-1/2

M5 14 12 281° 35-7/8

M6 14 12 225° 35-1/8

M7 14 12 90° 12

M8 14 12 90° 35-1/8

M9 14 12 90° 56-1/4

M10 14 12 190° 35-5/8

Coupon Blank Size Coupon Center Point

10.2.1 Uniformity of Tensile Properties 

Complete tensile test results for the aft bulkhead are shown in Table 10.2-2 through 

Table 10.2-5, with individual specimen results for orientations L, LT, ST, and ST45, 

respectively. The average values and standard deviations for each coupon blank and orientation 

are shown in Table 10.2-6 - Table 10.2-9. The overall average tensile property values and 

standard deviations for all coupon blanks tested are shown in Table 10.2-10 for each orientation. 

Tensile values shown in red were below MMPDS A-basis allowables and will be discussed in 

Section 10.2.2. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

91 of 223

NESC Request No.: TI-13-00884 

Table 10.2-2. Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead Material, 

Longitudinal (L) Orientation 

e

Specimen Coupon Meridian UTS 0.2% YS E 1.00" GL

No. Blank Angle Orient. (ksi) (ksi) (Msi) (%)

T-L1-L-1 58.75 39.11 10.09 12.90

T-L1-L-2 58.50 39.04 10.19 11.87

T-L1-L-3 58.97 39.22 10.50 12.74

T-L2-L-13 56.35 37.66 10.43 12.37

T-L2-L-14 56.56 37.79 10.47 12.68

T-L2-L-15 56.75 37.77 10.40 13.85

T-L3-L-25 54.03 36.65 10.40 14.10

T-L3-L-26 53.73 36.63 10.44 13.21

T-L3-L-27 53.41 36.52 10.42 11.92

T-L4-L-37 58.26 39.27 10.47 9.28

T-L4-L-38 58.07 38.79 10.48 10.74

T-L4-L-39 57.47 38.36 10.47 10.09

T-L5-L-49 ---- ---- ---- ----

T-L5-L-50 55.30 37.16 10.48 11.11

T-L5-L-51 56.22 37.61 10.49 11.19

T-L6-L-61 56.27 37.62 10.44 11.61

T-L6-L-62 56.27 37.75 10.46 10.54

T-L6-L-63 56.31 37.65 10.47 11.36

CP-406-190 59.66 39.48 10.55 11.77

CP-406-192 59.52 39.70 10.38 11.41

CP-406-194 58.36 38.72 11.92 11.30

CP-406-205 57.01 38.02 10.30 11.81

CP-406-207 56.95 38.08 10.15 11.64

CP-406-209 57.09 38.02 11.99 11.62

CP-406-220 54.93 37.26 10.30 13.74

CP-406-222 55.61 37.51 9.77 13.79

CP-406-224 55.02 37.18 9.38 15.23

CP-406-235 59.21 39.51 12.13 10.91

CP-406-237 59.93 39.78 9.75 11.41

CP-406-239 58.20 38.60 11.42 13.12

CP-406-250 58.49 38.44 9.59 11.38

CP-406-252 58.25 38.19 11.04 12.01

CP-406-254 56.79 37.48 10.75 12.47

CP-406-265 57.66 38.46 9.88 12.37

CP-406-267 57.54 38.14 9.88 12.41

CP-406-269 58.12 38.33 10.38 13.26

 ---- ---- ---- ---- ----

 ---- ---- ---- ---- ----

 ---- ---- ---- ---- ----

 ---- ---- ---- ---- ----

 ---- ---- ---- ---- ----

 ---- ---- ---- ---- ----

 ---- ---- ---- ---- ----

 ---- ---- ---- ---- ----

 ---- ---- ---- ---- ----

CP-406-127 58.48 38.99 9.92 14.37

CP-406-137 56.88 38.13 10.74 11.53

CP-406-147 55.79 37.65 10.24 12.32

M6

M5 281° L

L6 135° L

225° L

L5 259° L

L4 263° L

L3 330° L

L2 347° L

L1 351° L

M10 190° L

M7 90° L

M8 90° L

M9 90° L

M4 277° L

M3 30° L

M2 13° L

M1 9° L
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

92 of 223

NESC Request No.: TI-13-00884 

Table 10.2-3. Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead Material, LongTransverse (LT) Orientation 

e

Specimen Coupon Meridian UTS 0.2% YS E 1.00" GL

No. Blank Angle Orient. (ksi) (ksi) (Msi) (%)

T-L1-LT-4 57.64 38.33 10.44 10.63

T-L1-LT-5 57.75 38.55 10.48 10.11

T-L1-LT-6 57.86 38.67 10.38 10.14

T-L2-LT-16 56.33 37.49 10.38 10.73

T-L2-LT-17 56.46 37.56 10.39 10.12

T-L2-LT-18 56.10 37.35 10.44 10.61

T-L3-LT-28 53.77 36.58 10.40 10.66

T-L3-LT-29 53.78 36.69 10.37 9.36

T-L3-LT-30 54.16 36.76 10.42 10.38

T-L4-LT-40 56.38 38.34 10.46 7.85

T-L4-LT-41 56.69 38.33 10.37 7.99

T-L4-LT-42 57.10 38.41 10.40 8.63

T-L5-LT-52 55.26 37.11 10.37 10.08

T-L5-LT-53 54.99 36.92 10.41 11.00

T-L5-LT-54 55.21 37.02 10.39 11.48

T-L6-LT-64 56.37 37.42 10.41 12.98

T-L6-LT-65 56.11 37.41 10.43 11.87

T-L6-LT-66 56.27 37.66 10.41 10.48

CP-406-195 58.59 38.69 11.66 9.79

CP-406-197 58.53 38.71 11.06 10.09

CP-406-199 58.59 38.68 10.29 10.27

CP-406-210 57.49 38.03 9.38 10.49

CP-406-212 56.90 37.44 10.00 10.70

CP-406-214 57.48 38.00 10.67 11.17

CP-406-225 55.43 37.34 10.06 11.41

CP-406-227 55.33 37.08 10.10 12.36

CP-406-229 54.44 36.96 10.84 10.98

CP-406-240 58.93 38.80 11.37 10.20

CP-406-242 60.02 39.58 10.34 10.92

CP-406-244 58.14 38.88 10.13 9.21

CP-406-255 56.71 37.42 9.90 11.30

CP-406-257 56.82 37.48 10.02 10.87

CP-406-259 56.25 37.30 10.43 10.92

CP-406-270 56.50 37.45 10.94 10.36

CP-406-272 56.95 37.77 9.60 10.85

CP-406-274 56.72 37.54 9.82 10.64

CP-406-1 53.77 36.29 9.71 10.25

CP-406-11 54.57 37.02 10.04 10.64

CP-406-21 54.07 36.60 10.15 10.86

CP-406-43 57.61 38.57 10.64 9.67

CP-406-53 56.96 38.72 10.14 9.35

CP-406-63 58.79 39.05 10.66 10.36

CP-406-85 59.71 39.50 9.77 8.78

CP-406-95 59.04 39.53 10.28 8.64

CP-406-105 60.00 40.01 10.87 8.95

CP-406-169 54.37 36.93 10.06 9.63

CP-406-179 56.41 38.35 10.54 11.31

CP-406-189 56.88 38.32 9.83 9.51

M-5 281° LT

L6 135° LT

M-6 225° LT

L5 259° LT

L4 263° LT

L3 330° LT

L2 347° LT

L1 351° LT

M9 90° LT

M7 90° LT

M10 190° LT

M8 90° LT

M-4 277° LT

M-3 30° LT

M-2 13° LT

M-1 9° LT
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

93 of 223

NESC Request No.: TI-13-00884 

Table 10.2-4. Tensile Properties of the Spin Formed Al 2219-T62 aft Bulkhead Material, Short 

Transverse (ST) Orientation 

e

Specimen Coupon Meridian UTS 0.2% YS E 0.50" GL

No. Blank Angle Orient. (ksi) (ksi) (Msi) (%)

T-L1-ST-7 57.56 44.16 10.21 4.77

T-L1-ST-8 58.06 44.78 10.32 4.47

T-L1-ST-9 58.34 44.48 10.26 4.94

T-L2-ST-19 56.96 43.13 10.13 4.41

T-L2-ST-20 57.64 43.17 10.37 5.09

T-L2-ST-21 58.37 44.08 10.40 5.16

T-L3-ST-31 57.77 43.39 10.34 5.33

T-L3-ST-32 57.86 43.96 10.45 4.87

T-L3-ST-33 58.06 43.65 10.33 5.95

T-L4-ST-43 58.58 44.89 10.33 4.17

T-L4-ST-44 59.29 45.20 10.39 5.13

T-L4-ST-45 59.19 44.70 10.36 5.63

T-L5-ST-55 57.74 44.21 10.48 4.63

T-L5-ST-56 56.87 44.13 10.36 3.99

T-L5-ST-57 57.11 43.59 10.37 4.85

T-L6-ST-67 57.24 43.79 10.27 4.74

T-L6-ST-68 57.66 43.85 10.35 4.78

T-L6-ST-69 58.44 44.36 10.38 5.07

CP-406-200 58.62 38.32 10.95 4.28

CP-406-202 62.08 37.82 10.58 5.35

CP-406-204 59.87 36.53 9.59 5.13

CP-406-215 59.52 41.96 9.14 4.61

CP-406-217 60.49 41.44 9.46 4.62

CP-406-219 59.37 40.68 10.08 4.53

CP-406-230 56.21 37.64 9.72 5.08

CP-406-232 57.12 37.77 10.57 3.93

CP-406-234 57.90 36.50 10.26 4.04

CP-406-245 58.50 38.08 10.52 4.80

CP-406-247 60.28 39.54 10.21 4.14

CP-406-249 61.48 39.88 9.24 5.70

CP-406-260 58.61 38.52 10.14 3.77

CP-406-262 64.14 39.42 9.91 4.55

CP-406-264 56.71 38.10 9.75 3.54

CP-406-275 56.89 40.83 10.53 3.34

CP-406-277 59.36 40.08 8.76 4.77

CP-406-279 59.27 40.06 10.09 4.38

CP-406-22 58.15 43.76 10.39 4.9

CP-406-32 57.24 42.23 9.52 4.68

CP-406-42 58.21 43.61 9.76 4.83

CP-406-64 58.13 42.59 9.84 4.38

CP-406-74 58.94 44.48 9.39 4.05

CP-406-84 59.00 44.11 9.76 5.29

CP-406-106 60.87 45.55 9.33 4.49

CP-406-116 61.20 43.63 9.01 4.36

CP-406-126 57.50 43.80 9.44 3.52

CP-406-148 59.44 44.57 9.98 4.76

CP-406-158 59.59 44.79 10.04 5.01

CP-406-168 59.92 43.88 10.34 4.73

281° ST

M7 90° ST

M8 90° ST

L6 135° ST

M-6 225° ST

M-5

L5 259° ST

L4 263° ST

L3 330° ST

L2 347° ST

L1 351° ST

M10 190° ST

M9 90° ST

M-4 277° ST

M-3 30° ST

M-1 9° ST

M-2 13° ST
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

94 of 223

NESC Request No.: TI-13-00884 

Table 10.2-5. Tensile Properties of the Spin Formed Al 2219-T62 aft Bulkhead Material, Short 

Transverse 45° (ST45) Orientation 

e

Specimen Coupon Meridian UTS 0.2% YS E 0.50" GL

No. Blank Angle Orient. (ksi) (ksi) (Msi) (%)

T-L1-ST45-10 53.14 43.44 10.81 2.99

T-L1-ST45-11 49.34 37.53 10.62 2.82

T-L1-ST45-12 52.14 36.77 10.50 4.10

T-L2-ST45-22 54.36 38.00 10.73 5.01

T-L2-ST45-23 53.63 38.06 10.60 4.70

T-L2-ST45-24 54.01 39.28 10.82 4.58

T-L3-ST45-34 53.24 38.94 10.64 4.41

T-L3-ST45-35 52.85 40.71 10.31 3.25

T-L3-ST45-36 55.23 43.64 10.79 4.13

T-L4-ST45-46 51.76 38.65 10.84 3.33

T-L4-ST45-47 51.74 36.03 10.73 4.47

T-L4-ST45-48 49.80 36.38 10.50 3.38

T-L5-ST45-58 53.94 38.39 10.77 4.80

T-L5-ST45-59 53.76 37.82 10.87 4.80

T-L5-ST45-60 53.29 37.42 10.61 5.04

T-L6-ST45-70 55.52 47.54 10.91 2.64

T-L6-ST45-71 55.85 47.49 11.07 2.79

T-L6-ST45-72 54.30 38.62 10.90 4.48

L6 135° ST45

L5 259° ST45

L4 263° ST45

L3 330° ST45

L2 347° ST45

L1 351° ST45
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

95 of 223

NESC Request No.: TI-13-00884 

Table 10.2-6. Average Tensile Properties and Standard Deviations of the Spin Formed Al 2219-T62 

Aft Bulkhead Material, Longitudinal (L) Orientation 

e

Coupon UTS 0.2% YS E 1.00" GL

Blank Orient. (ksi) (ksi) (Msi) (%)

58.74 39.12 10.26 12.5 Average

0.23 0.09 0.21 0.56 Std Dev.

56.55 37.74 10.44 12.97

0.2 0.07 0.03 0.78

53.72 36.6 10.42 13.08

0.31 0.07 0.02 1.1

57.93 38.81 10.47 10.04

0.41 0.45 0.01 0.73

55.76 37.38 10.48 11.15

0.65 0.32 0.01 0.05

56.28 37.68 10.46 11.17

0.03 0.07 0.02 0.56

59.18 39.3 10.95 11.49

0.71 0.51 0.84 0.24

57.02 38.04 10.81 11.69

0.07 0.03 1.02 0.1

55.19 37.32 9.82 14.25

0.37 0.17 0.46 0.85

59.11 39.29 11.1 11.81

0.86 0.62 1.22 1.16

57.84 38.04 10.46 11.95

0.92 0.5 0.77 0.55

57.77 38.31 10.04 12.68

0.31 0.16 0.29 0.5

57.05 38.26 10.3 12.74

1.35 0.68 0.41 1.47

M10 L

M4 L

M5 L

M6 L

M1 L

M2 L

M3 L

L4 L

L5 L

L6 L

L1 L

L2 L

L3 L
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

96 of 223

NESC Request No.: TI-13-00884 

Table 10.2-7. Average Tensile Properties and Standard Deviations of the Spin Formed Al 2219-T62 

Aft Bulkhead Material, Long Transverse (LT) Orientation 

e

Coupon UTS 0.2% YS E 1.00" GL

Blank Orient. (ksi) (ksi) (Msi) (%)

57.75 38.52 10.43 10.29 Average

0.11 0.17 0.05 0.29 Std Dev.

56.3 37.47 10.41 10.49

0.18 0.11 0.03 0.32

53.9 36.68 10.4 10.13

0.23 0.09 0.03 0.69

56.72 38.36 10.41 8.16

0.36 0.04 0.04 0.41

55.16 37.02 10.39 10.85

0.15 0.1 0.02 0.71

56.25 37.5 10.42 11.77

0.13 0.14 0.01 1.25

58.57 38.69 11 10.05

0.03 0.01 0.69 0.24

57.29 37.82 10.01 10.79

0.34 0.33 0.64 0.35

55.07 37.13 10.34 11.58

0.55 0.2 0.44 0.7

59.03 39.09 10.61 10.11

0.94 0.43 0.66 0.86

56.59 37.4 10.11 11.03

0.3 0.09 0.28 0.24

56.72 37.59 10.12 10.61

0.22 0.17 0.72 0.25

54.14 36.64 9.97 10.58

0.4 0.37 0.23 0.31

57.79 38.78 10.48 9.79

0.93 0.25 0.29 0.52

59.58 39.68 10.31 8.79

0.49 0.29 0.55 0.16

55.89 37.87 10.14 10.15

1.33 0.81 0.36 1.01

L1 LT

L2 LT

L3 LT

L4

M9 LT

M10 LT

M5 LT

M6 LT

M7 LT

M8 LT

M2 LT

M3 LT

M4 LT

LT

L5 LT

L6 LT

M1 LT
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

97 of 223

NESC Request No.: TI-13-00884 

Table 10.2-8. Average Tensile Properties and Standard Deviations of the Spin Formed Al 2219-T62 

Aft Bulkhead Material, Short Transverse (ST) Orientation 

e

Coupon UTS 0.2% YS E 0.50" GL

Blank Orient. (ksi) (ksi) (Msi) (%)

57.99 44.48 10.26 4.73 Average

0.4 0.31 0.05 0.24 Std Dev.

57.65 43.46 10.3 4.89

0.7 0.54 0.15 0.41

57.9 43.67 10.37 5.38

0.14 0.29 0.07 0.54

59.02 44.93 10.36 4.98

0.39 0.25 0.03 0.74

57.24 43.98 10.4 4.49

0.45 0.34 0.07 0.45

57.78 44 10.33 4.87

0.61 0.31 0.06 0.18

60.19 37.55 10.37 4.92

1.75 0.93 0.7 0.57

59.79 41.36 9.56 4.59

0.61 0.65 0.48 0.05

57.08 37.3 10.19 4.35

0.85 0.7 0.43 0.63

60.09 39.17 9.99 4.88

1.5 0.96 0.66 0.78

59.82 38.68 9.93 3.96

3.86 0.68 0.2 0.53

58.51 40.32 9.8 4.16

1.4 0.44 0.92 0.74

57.87 43.2 9.89 4.8

0.54 0.84 0.45 0.11

58.69 43.73 9.66 4.57

0.49 1 0.24 0.64

59.86 44.33 9.26 4.12

2.05 1.06 0.22 0.53

59.65 44.41 10.12 4.83

0.25 0.47 0.19 0.15

L1 ST

L2 ST

L3 ST

ST

M1 ST

M2 ST

M3 ST

L4 ST

L5 ST

L6 ST

M10 ST

M7 ST

M8 ST

M9 ST

M4 ST

M5 ST

M6
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

98 of 223

NESC Request No.: TI-13-00884 

Table 10.2-9. Average Tensile Properties and Standard Deviations of the Spin Formed Al 2219-T62 

Aft Bulkhead Material, Short Transverse 45° (ST45) Orientation 

Table 10.2-10. Average Tensile Properties and Standard Deviation Values for the Spin Formed 

Al 2219-T62 aft Bulkhead Material 

The trends observed in the aft bulkhead tensile results, based on the average tensile values shown 

in Table 10.2-10, are representative of the trends observed for each coupon blank. Average 

tensile strengths and elongation values are essentially equivalent for the L and T orientations. Of 

note, however, is that the UTS and YS are highest in the ST orientation, by approximately 3% 

for UTS and 10% for YS as compared to the L and LT orientations. The ST UTS and YS values 

were greater than those for the ST45 orientation by approximately 10% and 6%, respectively. 

e

Coupon UTS 0.2% YS E 0.50" GL

Blank Orient. (ksi) (ksi) (Msi) (%)

51.54 39.25 10.65 3.30 Average

1.97 3.65 0.16 0.69 Std Dev.

54.00 38.44 10.72 4.77

0.36 0.73 0.11 0.22

53.77 41.10 10.58 3.93

1.28 2.37 0.25 0.61

51.10 37.02 10.69 3.73

1.13 1.42 0.17 0.65

53.66 37.88 10.75 4.88

0.33 0.49 0.13 0.14

55.22 44.55 10.96 3.30

0.81 5.13 0.10 1.02

ST45

L5 ST45

L6 ST45

L1 ST45

L2 ST45

L3 ST45

L4

e

UTS 0.2% YS E 1.00" GL

Orient. (ksi) (ksi) (Msi) (%)

57.12 38.17 10.46 12.14 Average

1.64 0.86 0.59 1.23 Std Dev.

56.67 37.89 10.35 10.32

1.67 0.90 0.42 1.02

58.69 42.16 10.05 4.66

1.54 2.67 0.47 0.56

53.22 39.71 10.72 3.98

1.76 3.51 0.18 0.84

* = 0.50" GL

L

LT

ST*

ST45*
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

99 of 223

NESC Request No.: TI-13-00884 

The UTS was lowest for the ST45 orientation, but YS was higher than for the L and T 

orientations. Elongation values in the ST orientation were about half those for the L and LT 

orientations. The average elongation value was lowest for the ST45 orientation, but was still 

nearly 4%. It is unclear whether the measured ST properties are unique to this plate or are the 

result of the spin forming deformation. 

To evaluate the variability in tensile properties in the aft bulkhead the average tensile test results 

were superimposed on the aft bulkhead cut plan as shown in Figure 10.2-2 through Figure 10.2-5 

for each orientation. Trends were evaluated as a function of meridian angle and distance from 

the pole. Tensile values shown in red fell below MMPDS A-basis design allowables. There 

appears to be a trend of increasing tensile strength from pole to rim for the L and LT 

orientations, but uniform properties about circumferential lines. Along the 0° to 180° meridian 

line, which is parallel to the original plate rolling direction, for the L and LT orientations, the 

coupon blanks furthest from the pole (L1, M1) exhibit both higher UTS and YS by 1.5 to 2 ksi 

than coupon blanks at the mid arc length (L2, M2) and become progressively lower in strength as 

one gets closer to the pole (L3, M3). The same trend appears at the opposing 180° meridian in 

coupon blank M10. Similar property trends exist along the 90° to 270° meridian line. 

Conversely, for a given meridian distance, tensile properties are uniform as one translates 

through the 0° to 360° meridian angles along circumferential lines (for example, meridian 

distance 35 inches, M2-L6-M10-M6-L5-M5-L2). These trends are not as systematic for the ST 

and ST45 due to greater scatter in the values for each coupon blank for these orientations. 

Table 10.2-8 and Table 10.2-9 illustrate the greater standard deviations for these orientations. 

To verify whether these trends are statistically significant, the individual tensile test results were 

plotted as a function of distance from the pole and meridian angle in Figure 10.2-6 through 

Figure 10.2-17. Also shown in these plots for reference are the MMPDS A-basis design 

allowables. Figure 10.2-6 and Figure 10.2-7 show tensile properties for the L and LT 

orientations along the 0° to 180° meridian line. The tensile data shows a clear trend of 

increasing strength with arc length distance from the pole for both of these orientations. The 

scatter in results for each coupon blank is less than the difference between populations of data 

clusters. Figure 10.2-8 and Figure 10.2-9 confirm that the trend is similar for the 90° - 270° 

meridian line. Similar plots for the ST and ST45 orientations, shown in Figure 10.2-10 through 

Figure 10.2-13 illustrate the larger scatter in this data and inability to discern any definitive 

trend. 

Plots of tensile data as a function of meridian angle at a distance of 35 inches from the pole, 

shown in Figure 10.2-14 through Figure 10.2-17, confirm that the tensile data is uniform for a 

given circumferential line. The scatter in the L and LT data (Figure 10.2-14 and Figure 10.2-15) 

is sufficiently small that the tensile properties are considered constant about this circumferential 

line. Scatter in the ST orientation (Figure 10.2-16) is greater than that in L and LT, but the data 

still reflect uniformity with meridian angle. The scatter in the ST45 data (Figure 10.2-17) is 

small with the exception of the YS at 135 degrees and the amount of data is much less than for 

the other orientations, but the data is reasonably uniform with meridian angle. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

100 of 223

NESC Request No.: TI-13-00884 

While this trend of increasing strength with arc length distance from the pole has been observed, 

budget and schedule prevent further studies on this matter. General metallurgical theory 

suggests that this trend may be related to the level of deformation imparted during spin forming 

both as a result of pressure from the forming tool as well as the strains induced during forming of 

the contour. The tool pressure is fairly uniform from the pole to the rim, but the imposed strain 

levels likely increase due to the superimposed forming stresses (tangential compressive and 

radial tensile and compressive) acting on the material, particularly towards the edge of the 

forming blank (2). However, these deformation strains should be relieved and the microstructure 

should undergo recovery during the high temperature solution heat treatment. 

One additional source of deformation may be related to the distortion and residual stress 

resulting from the quench following solution heat treatment. Because of the potential for nonuniform deformation through-thickness, it is recommended that additional tensile tests be 

conducted to evaluate through-thickness positions other than t/2. 

Variations in grain size described in Section 10.1 were attributed to the variation in forming 

stresses. All of the tensile tests were performed at the t/2 through-thickness position. The 

microstructure is fairly constant at t/2 throughout the regions examined in the aft bulkhead 

(Figure 10.1-6b) in terms of grain size and indications of residual deformation; however, there 

may be subtle variations that could explain the trends observed in the tensile properties. Other 

thickness positions exhibit greater variations, such as near the OML (Figure 10.1-6f). Of greater 

importance may be the effect of through-thickness grain size variations (See Figure 10.1-3a-e) on 

tensile properties. The through-thickness variation in microstructure should be examined for all 

spin formed components fabricated from Al 2219-T62 and tensile testing designed to sample the 

range of grain sizes. 

F-2. Tensile tests designed to determine tensile property uniformity over the aft bulkhead 

acreage noted that the tensile properties varied with location in the aft bulkhead. 

x For the L and LT orientations, a trend of increasing tensile and YS with arc length 

distance from the pole was evident. 

x Conversely, the properties were uniform in the circumferential direction. 

x The ST tensile properties were notably greater than those for the other 

orientations (L, LT, ST45), but elongations were about half. 

O-1. The rationale for the variations in tensile properties with location in the aft bulkhead was 

not fully characterized. The microstructure at the through-thickness location tested (t/2) 

was more uniform throughout the aft bulkhead than at other locations. 

R-1. The microstructural variability of the Orion first article spin formed aft bulkhead should 

be determined and mechanical property testing designed to sample regions of maximum 

and minimum grain size in order to evaluate the effect of variable microstructures, if 

observed. (F-1, F-2, O-1) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

101 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-2. Average Longitudinal (L) Tensile Properties Superimposed on the Aft Bulkhead Cut 

Plan 

0o

90o

180o

270o

Longitudinal Axis

Rolling Direction

FTU, ksi

FTY, ksi 

el , %

58.74 ksi

39.12 ksi

12.50 %

L1

56.55 ksi

37.74 ksi

12.97 %

L2

57.02 ksi

38.04 ksi

11.69 %

M2

53.72 ksi

36.60 ksi

13.08 %

L3

55.19 ksi

37.32ksi

14.25 %

M3

56.28 ksi

37.68 ksi

11.17 %

L6

57.05 ksi

38.26 ksi

12.74 %

M10

57.77 ksi

38.31 ksi

12.68 %

M6

55.76 ksi

37.38 ksi

11.15 %

L5

57.84 ksi

38.04 ksi

11.95 %

M5 59.11 ksi

39.29 ksi

11.81 %

M4

59.18 ksi

39.30 ksi

11.49 %

M1

57.93 ksi

38.81 ksi

10.04 %

L4
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

102 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-3. Average Long Transverse (LT) Tensile Properties Superimposed on the Aft 

Bulkhead Cut Plan 

0o

90o

180o

270o

Longitudinal Axis

Rolling Direction

FTU, ksi

FTY, ksi 

el , %

57.75 ksi

38.52 ksi

11.29 %

L1

56.30 ksi

37.47 ksi

10.49 %

L2

57.29 ksi

37.82 ksi

10.79 %

M2

53.90 ksi

36.68 ksi

10.13 %

L3

55.07 ksi

37.13ksi

11.58 %

M3

56.25 ksi

37.50 ksi

11.77 %

L6

55.89 ksi

37.87 ksi

10.15 %

M10

56.72 ksi

37.59 ksi

12.681.6

10.61 %

M6

55.16 ksi

37.02 ksi

10.85 %

L5

56.59 ksi

37.40 ksi

11.03 %

M5 59.03 ksi

39.09 ksi

10.11 %

M4

58.57 ksi

38.69 ksi

10.05 %

M1

56.72 ksi

38.36 ksi

8.16 %

L4

54.14 ksi

36.64 ksi

10.58 %

M7

57.79 ksi

38.78 ksi

9.79 %

M8

59.58 ksi

39.68 ksi

8.79 %

L6
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

103 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-4. Average Short Transverse (ST) Tensile Properties Superimposed on the Aft 

Bulkhead Cut Plan 

0o

90o

180o

270o

Longitudinal Axis

Rolling Direction

FTU, ksi

FTY, ksi 

el , %

57.99 ksi

44.48 ksi

4.73 %

L1

57.65 ksi

43.46 ksi

4.89 %

L2

59.79 ksi

41.36 ksi

4.59 %

M2

57.90 ksi

43.67 ksi

5.38 %

L3

57.08 ksi

37.30ksi

4.35 %

M3

57.78 ksi

44.00 ksi

4.87 %

L6

59.65 ksi

44.41 ksi

4.83 %

M10

58.51 ksi

40.32 ksi

4.16 %

M6

57.24 ksi

43.98 ksi

4.49 %

L5

59.82 ksi

38.68 ksi

3.96 %

M5 60.09 ksi

39.17 ksi

4.88 %

M4

60.19 ksi

37.55 ksi

4.92 %

M1

59.02 ksi

44.93 ksi

4.98 %

L4

57.87 ksi

43.20 ksi

4.80 %

M7

58.69 ksi

43.73 ksi

4.57 %

M8

59.86 ksi

44.33 ksi

4.12 %

L6
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

104 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-5. Average Short Transverse 45° (ST45) Tensile Properties Superimposed on the Aft 

Bulkhead Cut Plan 

0o

90o

180o

270o

Longitudinal Axis

Rolling Direction

FTU, ksi

FTY, ksi 

el , %

51.54 ksi

39.25 ksi

3.3 %

L1

54.00 ksi

38.44 ksi

4.77 %

L2

53.77 ksi

41.10 ksi

3.93 %

L3

55.22 ksi

44.55 ksi

3.30 %

L6

53.66 ksi

37.88 ksi

4.88 %

L5

51.10 ksi

37.02 ksi

3.73 %

L4
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

105 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-6. Longitudinal (L) Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead 

Material as a Function of Arc Length Distance from the Pole along the 0° to 180° Meridian Angle 

30

35

40

45

50

55

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

FTU, FTY,

ksi

Arc Length Distance from Pole, in.

0°- 180° Meridian Angle

L1 - FTU L2 - FTU L3 - FTU M1 - FTU

L1 - FTY L2 - FTY L3 - FTY M1 - FTY

M2 - FTU M3 - FTU M10 - FTU MMPDS - FTU

M2 - FTY M3 - FTY M10 - FTY MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

106 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-7. Long Transverse (LT) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Arc Length Distance from the Pole along the 0° to 180° 

Meridian Angle 

30

35

40

45

50

55

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

FTU, FTY,

ksi

Arc Length Distance from Pole, in.

0°- 180° Meridian Angle

L1 - FTU L2 - FTU L3 - FTU M1 - FTU

L1 - FTY L2 - FTY L3 - FTY M1 - FTY

M2 - FTU M3 - FTU M10 - FTU MMPDS - FTU

M2 - FTY M3 - FTY M10 - FTY MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

107 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-8. Longitudinal (L) Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead 

Material as a Function of Arc Length Distance from the Pole along the 90° to 270° Meridian Angle 

30

35

40

45

50

55

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

FTU, FTY,

ksi

Arc Length Distance from Pole, in.

90°- 270° Meridian Angle

L4 - FTU L5 - FTU M4 - FTU

M5 - FTU L4 - FTY L5 - FTY

M4 - FTY M5 - FTY M7 - FTU

M8 - FTU M9 - FTU MMPDS - FTU

M7 - FTY M8 - FTY M9 - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

108 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-9. Long Transverse (LT) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Arc Length Distance from the Pole along the 90° to 270° 

Meridian Angle 

30

35

40

45

50

55

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

FTU, FTY,

ksi

Arc Length Distance from Pole, in.

90°- 270° Meridian Angle

L4 - FTU L5 - FTU M4 - FTU M5 - FTU

L4 - FTY L5 - FTY M4 - FTY M5 - FTY

M7 - FTU M8 - FTU M9 - FTU MMPDS - FTU

M7 - FTY M8 - FTY M9 - FTY MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

109 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-10. Short Transverse (ST) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Arc Length Distance from the Pole along the 0° to 180° 

Meridian Angle 

30

35

40

45

50

55

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

FTU, FTY,

ksi

Arc Length Distance from Pole, in.

0°- 180° Meridian Angle

L1 - FTU L2 - FTU L3 - FTU M1 - FTU

L1 - FTY L2 - FTY L3 - FTY M1 - FTY

M2 - FTU M3 - FTU M10 - FTU MMPDS - FTU

M2 - FTY M3 - FTY M10 - FTY MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

110 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-11. Short Transverse 45o (ST45) Tensile Properties of the Spin Formed Al 2219-T62 

Aft Bulkhead Material as a Function of Arc Length Distance from the Pole along the 0° to 180° 

Meridian Angle 

30

35

40

45

50

55

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

FTU, FTY,

ksi

Arc Length Distance from Pole, in.

0°- 180° Meridian Angle

L1 - FTU L2 - FTU L3 - FTU MMPDS - FTU

L1 - FTY L2 - FTY L3 - FTY MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

111 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-12. Short Transverse (ST) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Arc Length Distance from the Pole along the 90° to 270° 

Meridian Angle 

30

35

40

45

50

55

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

FTU, FTY,

ksi

Arc Length Distance from Pole, in.

90°- 270° Meridian Angle

L4 - FTU L5 - FTU M4 - FTU M5 - FTU

L4 - FTY L5 - FTY M4 - FTY M5 - FTY

M7 - FTU M8 - FTU M9 - FTU MMPDS - FTU

M7 - FTY M8 - FTY M9 - FTY MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

112 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-13. Short Transverse 45o (ST45) Tensile Properties of the Spin Formed Al 2219-T62 

Aft Bulkhead Material as a Function of Arc Length Distance from the Pole along the 90° to 270° 

Meridian Angle 

30

35

40

45

50

55

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

FTU, FTY,

ksi

Arc Length Distance from Pole, in.

90°- 270° Meridian Angle

L4 - FTU L5 - FTU MMPDS - FTU

L4 - FTY L5 - FTY MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

113 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-14. Longitudinal (L) Tensile Properties of the Spin Formed Al 2219-T62 Aft Bulkhead 

Material as a Function of Meridian Angle along the R35 Circumferential Arc Length 

30

35

40

45

50

55

60

0 45 90 135 180 225 270 315 360

FTU, FTY

ksi

Meridian Angle, degrees

R35 Circumferential

L2 - FTU L5 - FTU L6 - FTU M2 - FTU

L2 - FTY L5 - FTY L6 - FTY M2 - FTY

M5 - FTU M6 - FTU M10 - FTU MMPDS - FTU

M5 - FTY M6 - FTY M10 - FTY MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

114 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-15. Long Transverse (LT) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Meridian Angle along the R35 Circumferential Arc Length 

30

35

40

45

50

55

60

0 45 90 135 180 225 270 315 360

FTU, FTY

ksi

Meridian Angle, degrees

R35 Circumferential

L2 - FTU L5 - FTU L6 - FTU M2 - FTU

L2 - FTY L5 - FTY L6 - FTY M2 - FTY

M5 - FTU M6 - FTU M8 - FTU M10 - FTU

M5 - FTY M6 - FTY M8 - FTY M10 - FTY

MMPDS - FTU MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

115 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-16. Short Transverse (ST) Tensile Properties of the Spin Formed Al 2219-T62 Aft 

Bulkhead Material as a Function of Meridian Angle along the R35 Circumferential Arc length 

30

35

40

45

50

55

60

0 45 90 135 180 225 270 315 360

FTU, FTY

ksi

Meridian Angle, degrees

R35 Circumferential

L2 - FTU L5 - FTU L6 - FTU M2 - FTU

L2 - FTY L5 - FTY L6 - FTY M2 - FTY

M5 - FTU M6 - FTU M8 - FTU M10 - FTU

M5 - FTY M6 - FTY M8 - FTY M10 - FTY

MMPDS - FTU MMPDS - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

116 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-17. Short Transverse 45° (ST45) Tensile Properties of the Spin Formed Al 2219-T62 

Aft Bulkhead Material as a Function of Meridian Angle along the R35 Circumferential Arc Length 

10.2.2 Comparison with Handbook Data and Other T6 and T8 Products 

The average tensile properties of the spin formed aft bulkhead shown in Table 10.2-10 were 

compared with data from numerous sources to assess the effects of spin forming when compared 

with rolled plate and other formed products heat treated to the T6 temper. Limited data were 

found in handbooks and open literature publications for Al 2219-T6 products so a variety of 

product forms were used in this evaluation. Comparisons were also made with T8 products to 

determine the reduction in tensile properties that designers will need to accommodate if spin 

forming is adopted for the aft bulkhead. In most cases, data for 2219-T6 and T8 products were 

available for L and T orientations; however, very little data were available for the ST orientation 

and no published values were available for the ST45 orientation. 

30

35

40

45

50

55

60

0 45 90 135 180 225 270 315 360

FTU, FTY

ksi

Meridian Angle, degrees

R35 Circumferential

L2 - FTU L5 - FTU L6 - FTU

MMPDS - FTU L2 - FTY L5 - FTY
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

117 of 223

NESC Request No.: TI-13-00884 

For comparison with wrought plate products, the MMPDS A- and B-basis design properties (17) 

and the Aluminum Association’s typical properties (18) for wrought Al 2219-T62, T851, and 

T87 plate are shown in Table 10.2-11 and Table 10.2-12, respectively. It is recognized that in 

this study typical properties of the aft bulkhead are compared with statistically derived 

allowables; however, these represent the material properties typically used by designers and 

provide an indication of whether the aft bulkhead properties will have the properties assumed in 

the design. It is also noteworthy that the ST orientation data from the aft bulkhead was compared 

with L and LT allowables since there are no allowables for the ST orientation specified in 

MMPDS. Typical tensile properties for spin formed Al 2219-T62 products were obtained from 

three sources for direct comparison to determine whether the aft bulkhead was “in family” with 

similar products. These included the FPVBH demonstration article presented in Table 10.2-13 

(1), (19), (20); domes produced for NASA’s Cryogenic Propellant Storage and Transfer (CPST) 

Program (Table 10.2-14) (21); and other domes produced for commercial customers 

(Table 10.2-15) (22). For comparison with other fabricated product forms, minimum tensile 

properties for Al 2219-T6 forgings and rolled or forged rings are shown in Table 10.2-16 (23). 

Based on the overall averages (Table 10.2-10), tensile strengths of the aft bulkhead in the L and 

LT orientations were about 5% higher than the MMPDS A-basis allowables for T62 plate 

(Table 10.2-11). The ST properties were even higher with UTS 8% and YS 15% higher than the 

L and LT orientation allowables. The elongation values exceeded the design values. The L and 

LT strengths were slightly lower, but within 5% of typical values reported by the Aluminum 

Association (Table 10.2-12). Al 2219 is generally considered an isotropic material with 

properties in the L, LT, and ST orientations generally agreeing within less than approximately 

5% (see Table 10.2-11 and Table 10.2-16). The ST YS in the aft bulkhead was 10% greater than 

for L and T. It is unclear whether the higher ST YS is inherent in the plate used in fabrication of 

the spin forming blank or is related to the spin forming process. 

Individual specimen results and average values for each coupon blank were compared with 

MMPDS A-basis allowables to determine whether there were any regions of concern in the aft 

bulkhead. Values below MMPDS are highlighted in red in Tables 10.2-2 through 10.2-10 for 

individual specimens, averages for the coupon blanks, and the overall average. To illustrate the 

aft bulkhead locations that have strength or elongation values below MMPDS, those values are 

shown in red in Figures 10.2-2 through 10.2-5. In addition, the MMPDS value is shown on the 

data plots in Figures 10.2-7 through 10.2-15. Two of three L and LT specimens from coupon 

blank L3, which is near the pole, exhibit UTS values just below the MMPDS A-basis UTS. This 

is reflected in the coupon blank average UTS; however, the overall average L and LT UTS is 

well above the MMPDS value. Strength values for the ST orientation were above, but 

elongations below MMPDS values at all locations. For the ST45 orientation, all elongation 

values and all except one UTS value were below MMPDS. All YS values for all locations and 

orientations were above the MMPDS YS. 

The tensile properties of the aft bulkhead agreed well with the typical properties for other 

Al 2219-T62 spin formed products. The aft bulkhead strength levels were slightly lower than the 

spin formed FPVBH and the domes produced for the CPST Program and commercially by 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

118 of 223

NESC Request No.: TI-13-00884 

Spincraft. The L and LT UTS and YS were within 3% and 6%, respectively, of values for the 

FBVBH (Table 10.2-13). The UTS was about 5% lower and YS 10% lower than the CPST and 

Spincraft domes (Table 10.2-14 and Table 10.2-15). Conversely, the ST tensile properties of the 

aft bulkhead were higher than those of the CPST domes. The UTS was about 2% higher and the 

YS 5% higher than the values for the CPST domes. The variations in tensile strength may be 

related to the amount of deformation related to forming these different geometries. The FPVBH 

experienced some thinning during spin forming and the complex geometry likely generated 

greater deformation. While some details of the Spincraft domes are proprietary it was confirmed 

that the domes were of larger scale than the aft bulkhead and had a complex thickness profile. 

The deformation was likely lower in the aft bulkhead than the FPVBH and Spincraft domes due 

to the gradual curvature and comparatively simple geometry of the aft bulkhead. 

Tensile strengths in the L and LT orientation compared well with minimum values for hand and 

die forgings and rolled or forged rings (Table 10.2-16), with some values higher and some lower, 

but all within 5% of the published minimums. However, strengths in the ST orientation were 

10 to 15% higher than values for hand forgings. Typical elongation values were higher in all 

comparisons. 

The L and LT tensile properties of the spin formed aft bulkhead are consistent (in family) with 

wrought plate and other fabricated product forms in the T62 temper. Orion design trade studies 

use the MMPDS A-basis values for T62 wrought plate to analyze the benefits of spin forming the 

aft bulkhead because design values do not exist for spin formed products. The tensile results of 

this aft bulkhead should build confidence in the spin forming fabrication method. Currently, 

some elements of the Orion CM are multi-piece welded construction of machined thick Al 2219-

T851 plate. The tensile properties of the spin formed aft bulkhead are lower than for T851 plate 

(Table 10.2-11 and Table 10.2-12) as expected due to the increased precipitation strengthening in 

T851 wrought products that is imparted by the 1.5 to 3.0% cold stretch prior to artificial aging. 

The thick-plate convex spin forming process cannot accommodate stretch or cold work thus only 

T6 final temper can be produced. The properties of the spin formed aft bulkhead are comparable 

to T62 plate and other wrought products. The UTS values in the L and LT orientations of the aft 

bulkhead are about 10% lower than MMPDS A-basis allowables for T851 plate (Table 10.2-11) 

and 15% less than typical values (Table 10.2-12). The YS values in both orientations are about 

20% lower than the MMPDS A-basis allowables and 30% lower than typical values. It should 

be recognized that, based on MMPDS A-basis values, the UTS and YS of T62 plate are lower 

than for T851 plate by 10% and 30%, respectively, and lower than for T87 plate by 17% and 

40%, respectively. The lower tensile strength of the spin formed 2219-T62 aft bulkhead material 

compared with 2219-T851 and T87 plateS is due differences in material temper and not the spin 

forming process. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

119 of 223

NESC Request No.: TI-13-00884 

F-3. The tensile properties of the spin formed Al 2219-T62 aft bulkhead material were typical 

for established 2219-T62 products. 

x Tensile properties were comparable to the MMPDS design properties for T62 

wrought plate and other fabricated products in the T6 temper, such as spin formed 

domes, forgings and rolled rings. 

x Tensile properties were lower than those for Al 2219-T851 and T87 plate, as 

expected due to the increased precipitation strengthening in T8 temper wrought 

products that is imparted by the cold stretch/work prior to artificial aging. 

x The lower tensile strength of the spin formed Al 2219-T62 aft bulkhead material 

compared with Al 2219-T851 and T87 plate is due to differences in material 

temper and not the spin forming process. 

O-2. Limited data was available in handbooks or open literature publications for Al 2219-T6 

material for comparison with the aft bulkhead properties, consequently it was difficult to 

assess the aft bulkhead in the context of other commercial Al 2219-T6 products. 

x Tensile data were unavailable in handbooks or open literature publications for the 

ST and ST45 orientations, consequently these properties could only be assessed in 

comparison with established values for the L and LT orientations. 

R-2. Additional testing should be performed on first article and initial serial production aft 

bulkhead components to generate data to populate the material property database for 

Al 2219-T6 spin formed products. (O-2) 

x Tensile testing should be continued until sufficient data is generated to 

demonstrate consistency in material properties and build confidence that the spin 

forming process is reproducible. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

120 of 223

NESC Request No.: TI-13-00884 

Table 10.2-11. Design Tensile Properties of Al 2219-T62, T851 and T87 Sheet and Plate (17) 

Specification

Form

Temper

Thickness, in

Basis A B A B A B A B A B A B A B

Mechanical Properties:

Ftu, ksi

L 54 55 61 62 61 62 ---- ---- ---- ---- ---- ---- ---- ----

LT 54 55 62 63 62 63 62 63 60 61 59 60 57 58

Fty, ksi

L 36 37 47 48 47 48 ---- ---- ---- ---- ---- ---- ---- ----

LT 36 37 46 47 46 47 45 46 44 45 43 44 42 43

e, % (S-basis)

LT d ---- 8 ---- 7 ---- 6 ---- 5 ---- 5 ---- 4 ----

E, 103 ksi

d T62: 0.250-1.000 in: 8%; 1.001-2.000 in.: 7%

AMS-QQ-250/30, AMS 4599

Sheet and Plate

AMS-QQ-250/30, AMS 4031

0.020-2.000

T62 T851

0.250 - 1.000 1.001 - 2.000 2.001 - 3.000

10.5

3.001 - 4.000 4.001 - 5.000 5.001 - 6.000

Specification

Form

Temper

Thickness, in

Basis A B A B A B A B A B A B A B

Mechanical Properties:

Ftu, ksi

L 54 55 63 64 63 64 63 64 63 64 61 62 ---- ----

LT 54 55 64 65 64 65 64 65 64 65 62 63 61 62

ST ---- ---- ---- ---- ---- ---- 59 60 56 57 52 53 ---- ----

Fty, ksi

L 36 37 50 51 50 51 50 51 50 51 49 50 ---- ----

LT 36 37 51 52 51 52 51 52 51 52 51 51 49 50

ST ---- ---- ---- ---- ---- ---- 51 52 50 51 48 49 ---- ----

e, % (S-basis)

LT d ---- 7 ---- 6 ---- 6 ---- 6 ---- 4 ---- 3 ----

E, 103 ksi

d T62: 0.250-1.000 in: 8%; 1.001-2.000 in.: 7%

 T87

0.250 - 1.000 1.001 - 1.500 1.501 - 2.000 2.001 - 3.000 3.001 - 4.000 4.001 - 5.000

T62

0.020-2.000

AMS-QQ-250/30, 

AMS 4031

Sheet and Plate

10.5

AMS-QQ-250/30, AMS 4613

Table 10.2-12. Typical Tensile Properties of Al 2219-T62, T851, and T87 Sheet and Plate (18) 

UTS YS E e 

(ksi) (ksi) (Msi) (%)

2219-T851 66 50 10.5 12

2219-T87 68 56 10.5 10

2219-T62 58 40 10.5 12
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

121 of 223

NESC Request No.: TI-13-00884 

Table 10.2-13. Average Tensile Properties for the Spin Formed Al 2219-T62 FPVBH Material (1), 

(19), (20) 

UTS 0.2% YS E e

Location Orient. (ksi) (ksi) (Msi) (%)

60.05 40.8 10.6 9.25 Average

0.92 0.71 0.71 1.06 Std Dev.

60.65 40 10.85 9

0.21 0.14 0.78 1.41

57.53 40.53 10.03 9.25

0.67 2.08 0.22 0.96

58.05 40.73 10.1 10.63

0.59 1.64 0.22 1.7

57.3 40.45 9.85 6.5

0.14 0.64 0.21 2.12

56.95 39.6 9.55 13

0.07 0.85 0.78 0

58.29 40.59 10.16 8.33 Average

1.53 0.18 0.39 1.59 Std Dev.

58.55 40.11 10.17 10.88

1.9 0.57 0.65 2.01

L

LT

All 

coupon 

blank 

locations 

Cone

L

LT

Barrel

L

LT

Pole

L

LT
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

122 of 223

NESC Request No.: TI-13-00884 

Table 10.2-14. Tensile Properties of Spin Formed Al 2219-T62 Domes for the CPST Program (21) 

Dome Specimen UTS, YS, e,

S/N ID Location Orient. Condition* Source ksi ksi %

31140-1 31140-1-P2-L pole in-plane (L) T62 LAT 59.0 41.0 12

31140-2 31140-2-P2-L pole in-plane (L) T62 LAT 60.0 42.2 13

31140-3 31140-3-P2-L pole in-plane (L) T62 LAT 60.0 41.7 13

31140-1 31140-1-P1-LT pole in-plane (LT) T62 LAT 60.5 42.0 10

31140-2 31140-2-P1-LT pole in-plane (LT) T62 LAT 60.5 41.1 11

31140-3 31140-3-P1-LT pole in-plane (LT) T62 LAT 60.0 43.6 11

31140-1 120551001 pole in-plane T62 MSFC 57.0 35.4 10.4

31140-1 120551005 pole in-plane T62 MSFC 57.5 39.0 11.7

31140-1 120551003 pole ST T62 MSFC 57.1 37.8 4.2

31140-2 120551013 pole in-plane T62 + SR MSFC 57.3 35.8 10.1

31140-2 120551017 pole in-plane T62 + SR MSFC 56.7 39.6 11.2

31140-2 120551015 pole ST T62 + SR MSFC 59.3 41.3 3.9

31140-1 31140-1-E2-L rim in-plane (L) T62 LAT 59.5 41.9 11

31140-2 31140-2-E2-L rim in-plane (L) T62 LAT 60.5 42.2 11

31140-3 31140-3-E2-L rim in-plane (L) T62 LAT 59.5 41.4 12

31140-1 31140-1-E1-LT rim in-plane (LT) T62 LAT 59.0 41.5 11

31140-2 31140-2-E1-LT rim in-plane (LT) T62 LAT 58.5 41.3 11

31140-3 31140-3-E1-LT rim in-plane (LT) T62 LAT 59.0 40.6 11

31140-1 120551021 rim in-plane T62 + SR MSFC 57.1 35.4 10.6

31140-1 120551023 rim in-plane T62 + SR MSFC 59.4 38.9 9.3

31140-1 120551019 rim ST T62 + SR MSFC 55.4 40.0 4.0

31140-2 120551009 rim in-plane T62 + SR MSFC 58.4 39.0 12.3

31140-2 120551011 rim in-plane T62 + SR MSFC 58.8 40.9 9.9

31140-2 120551007 rim ST T62 + SR MSFC 58.3 41.3 4.9

LAT lot acceptance test

SR Stress relief thermal cycle at 300°F ± 15°F for 8 hours
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

123 of 223

NESC Request No.: TI-13-00884 

Table 10.2-15. Typical tensile properties of spin formed Al 2219-T62 domes commercially 

produced by Spincraft. Also shown for comparison is the Alcoa plate lot certification tensile 

properties. (22). 

Spincraft Alcoa

Dome Plate Lot UTS YS EL4D UTS YS EL4D UTS YS EL4D

S/N H/N (ksi) (ksi) (%) (ksi) (ksi) (%) (ksi) (ksi) (%)

LT 58.9 41.0 11.1 59.0 42.7 12.0 59.0 41.3 10.0

L 58.5 40.6 11.5 60.0 43.4 13.0 59.0 41.6 12.0

LT 59.2 40.7 11.1 60.5 43.9 10.0 60.5 41.7 9.0

L 59.3 40.8 11.3 60.0 42.9 10.0 59.0 40.4 10.0

LT 59.7 40.8 11.8 60.5 44.0 13.0 60.5 42.4 10.0

L 60.0 41.0 10.6 60.5 44.3 11.0 59.5 42.1 10.0

LT 58.5 40.8 11.7 59.5 42.5 10.0 60.0 42.5 10.0

L 58.7 41.0 11.8 59.5 42.8 12.0 59.5 42.8 10.0

LT 60.9 42.0 8.2 55.8 37.7 13.0 60.1 43.4 8.5

LT 60.3 41.5 8.5 58.3 38.5 11.0 59.8 42.7 10.0

L ------ ------ ------ 56.9 40.4 12.0 58.8 43.9 10.0

L ------ ------ ------ 57.7 39.3 14.0 59.7 42.4 11.0

LT 60.9 41.9 10.7 62.5 45.3 11.0 60.0 42.1 11.0

LT 61.3 41.8 10.2 61.5 43.4 10.0 60.0 42.1 11.0

L ------ ------ ------ 60.5 43.3 10.0 59.5 41.7 11.0

L ------ ------ ------ 61.0 43.5 11.0 59.5 42.0 11.0

LT 59.7 40.6 11.1 60.0 42.9 10.0 58.0 41.8 8.0

LT 59.6 40.8 11.0 59.5 42.3 10.0 58.5 41.7 10.0

L ------ ------ ------ 60.5 42.9 10.0 57.5 41.4 8.0

L ------ ------ ------ 59.5 42.3 10.0 58.0 40.8 10.0

Average 59.9 41.2 10.5 59.7 42.3 11.0 59.6 42.2 9.8

Std. Dev. 0.93 0.55 1.24 1.83 2.40 1.25 0.85 0.61 0.98

Average 59.1 40.9 11.3 59.6 42.5 11.3 59.0 41.9 10.3

Std. Dev. 0.68 0.19 0.51 1.32 1.52 1.42 0.73 1.00 1.06

Spin Formed Dome Tensile Properties

Alcoa Plate Lot Cert. Data

Orient.

Polar Tensile Coupons Equator Tensile Coupons

LT

L

31152-1 660931-1

31152-2 660941-1

31153-2 478411-1

31163-2 414081-1

31153-3 660951-1

31172-1R 528431-1

31163-1 414091-1
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

124 of 223

NESC Request No.: TI-13-00884 

Table 10.2-16. Minimum Tensile Properties for Al 2219-T6 Forgings and Rolled or Forged Rings 

(23) 

UTS 0.2% YS e

Orient. ksi ksi % in 4D 

L 58.0 38.0 8

LT 56.0 36.0 4

Minimum tensile properties

Die Forgings

UTS 0.2% YS e

Orient. ksi ksi % in 4D 

L 58.0 40.0 6

LT 55.0 37.0 4

ST 53.0 35.0 2

Minimum tensile properties

Hand Forgings

UTS 0.2% YS e

Orient. ksi ksi % in 4D 

Tangential 56.0 40.0 6

Axial 55.0 37.0 4

Minimum tensile properties

Rolled or Forged Rings

10.2.3 Tensile Fractography 

Representative tensile specimens were chosen for examination of the fracture surfaces with a 

combination of macroscopic and microscopic techniques. Macroscopic evaluation was 

performed with a digital camera and stereo microscope. Microscopic examination was 

conducted via scanning electron microscopy. Eighteen specimens were tested for the L, LT, ST, 

and ST45 orientations. All specimens were inspected visually after failure and representative 

samples were selected for more detailed examination to evaluate fracture morphology. 

Three specimens representing the typical tensile failures observed for the L and LT orientations 

are shown in Figure 10.2-18. In general, the fracture surfaces as seen from the top-view in 

Figure 10.2-18 appear similar with macroscopic dimples, which indicate a ductile fracture mode. 

In all cases the specimens exhibited strain bands, which can be seen in the side view in Figure 

10.2-19. Differences in the overall fracture path were observed as can be seen in the side-view 

of the fracture surfaces, with specimens exhibiting two slant fracture modes: full-slant or doubleslant tensile fracture, both of which are typical of tensile fractures in Al plate. Of the 18 L 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

125 of 223

NESC Request No.: TI-13-00884 

orientation tensile specimens, 13 failed with a full-slant fracture at approximately 45 degrees to 

the tensile axis (see Figure 10.2-18 middle, specimen L2-L-14), while 5 failed in a generally 

double-slant pattern along with each slant oriented approximately 45 degrees to the tensile axis 

(see Figure 10.2-18 left, specimen L1-L-3). For the LT orientation, seventeen failed along a 

single, 45-degree slant (see Figure 10.2-18 right, specimen L2-LT-16) and only one failed in a 

double-slant manner. Nearly all of the ST and ST45 samples failed in the full-slant fracture 

mode; the remaining few were somewhat flatter slant fractures. The alignment of the fracture 

surface at roughly ±45 degrees to the tensile axis is common in ductile failures along the 

macroscopic plane(s) of maximum shear stress. Macroscopically, the tensile specimens 

exhibited features considered typical of ductile failure along planes of maximum shear stress, 

primarily as full-slant failures with some double-slant failures. 

Figure 10.2-18. Representative Macroscopic View of the Fracture Surfaces from the top and side 

views for Tensile Specimens L1-L-3 (left), L2-L-14 (middle), and L2-LT-16 (right) 

At the microscopic level, all three specimens shown in Figure 10.2-18 were found to exhibit 

similar features and are representative of all L and LT specimens tested. Hence, only SEM 

images are presented for one of the specimens, L2-L-14. In Figure 10.2-19, SEM images at 

sequentially higher magnifications (progressing clockwise from top right as indicated by the 

arrows) are shown. In Figure 10.2-19a, the entire surface is captured at low-magnification, 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

126 of 223

NESC Request No.: TI-13-00884 

revealing a fibrous appearance with noticeable ridges and valleys, which is typical of fracture in 

Al alloy plate. The fibrous features are associated with transgranular fracture of elongated grains 

in rolled plate and the ridges with transition between grains. At 50x (Figure 10.2-19b), regions 

of transgranular microvoid coalescence are observed along with regions of lower ductility 

fracture and small delaminations, features that generally correlated with grain size. Higher 

magnification (500x, Figure 10.2-19c) confirms that all regions exhibit microvoid coalescence 

consistent with ductile fracture, with dimple sizes larger in the regions of transgranular fracture. 

At 2,000x (Figure 10.2-19d), dimples ranging from sub-micron size to approximately 5 μm are 

observed. Overall, fractography indicates the L and LT tensile specimens failed in a typical, 

ductile manner, which correlates well with the elongation values measured during the tensile 

tests. 

Figure 10.2-19. SEM Images of the Fracture Surface of Tensile Specimen L2-L-14 at a) 14x; 

b) 50x; c) 500x and d) 2,000x Magnifications 

SEM fractography results are shown in Figure 10.2-20 and Figure 10.2-21 for representative ST 

and ST45 specimens. The ST fracture surface shown in Figure 10.2-20 represents the flatter 

slant fracture mode. Low magnifications (views a and b) exhibit a stepwise fracture surface 

illustrating propagation on elongated grain boundaries. Higher magnification (view c) reveals 

shallow microvoid coalescence initiated at constituent particles, often presented as clusters and 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

127 of 223

NESC Request No.: TI-13-00884 

stringers of smaller particles (view (d)). The ST45 fracture surface shown in Figure 10.2-21 

exhibits some fibrous texture associated with transgranular crack propagation, but without the 

pronounced ridges and valleys noted on the L and LT fracture surfaced. Large microvoids are 

noted, again forming at constituent particle populations; however, more colonies of small 

microvoids are noted than in the ST fracture. The features noted in the ST and ST45 fractures 

are consistent with the lower ductility levels measured during tensile tests when compared with 

the L and LT orientations. 

Figure 10.2-20. SEM Images of the Fracture Surface of Tensile Specimen ST-43 at (a) 25x; (b) 50x; 

(c) 500x; and (d) 2,000x Magnifications 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

128 of 223

NESC Request No.: TI-13-00884 

Figure 10.2-21. SEM Images of the Fracture Surface of Tensile Specimen ST45-12 at (a) 25x; (b) 

50x; (c) 500x; and (d) 2,000x Magnifications 

10.3 Fracture Toughness Test Results 

Figure 10.3-1 shows the aft bulkhead cut plan with the location of coupon blanks from which 

fracture specimens were excised for fracture toughness testing highlighted in yellow. Table 

10.3-1 shows the size and location of these coupon blanks with respect to the original plate 

rolling direction and distance from the aft bulkhead pole to the coupon blank center point. These 

coupon blank locations were designed to determine uniformity of fracture properties throughout 

the aft bulkhead and were evaluated along selected meridian and circumferential lines. 

An additional goal of these tests was to determine how these properties compare to wrought plate 

in the T6 and T8 tempers and to other fabricated product forms in the T62 temper. These results 

will assist the Orion designers in assessing the attributes of the spin form fabrication process for 

the aft bulkhead and identify any deficiencies or “show stoppers” associated with this fabrication 

process. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

129 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-1. Aft Bulkhead Cut Plan showing the Location of the Fracture Coupon Blanks 

highlighted in Yellow 

Table 10.3-1. Fracture Toughness Coupon Blank Locations and Orientations 

Longitudinal Transverse Meridian Arc Length

Coupon Dimension, Dimension, Angle , from dome CL

Blank in. in. degrees in.

M1 14 12 9° 54-5/8

M2 14 12 13° 36

M3 14 12 30° 16-1/8

M4 14 12 277° 55-1/2

M5 14 12 281° 35-7/8

M6 14 12 225° 35-1/8

Coupon Blank Size Coupon Center Point

10.3.1 Uniformity of Fracture Properties 

A summary of the fracture toughness test results for the Al 2219-T62 aft bulkhead material is 

provided in Table 10.3-2. All but five specimens were valid per the ASTM E1820 (8) 

specification. In each case the invalidity was related to the difference between the estimated 

crack extension and the measured crack extension. In each case the deviation was considered 

minor and inconsequential to the toughness results. Comprehensive data analyses are provided 

in the Appendix (see Section 20.3). Fracture toughness comparisons were based on KJIC values 

listed in Table 10.3-2. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

130 of 223

NESC Request No.: TI-13-00884 

Table 10.3-2. Summary of Fracture Data for the Spin Formed Al 2219-T62 Aft Bulkhead Material 

Specimen ID Coupon Blank Orientation JIC (in-lb/in2

) KJIC (ksi√in)

CP-406-191 105.6 35.1

CP-406-193 114.8 36.6

CP-406-196 91.5* 32.7

CP-406-198 90.6* 32.5

CP-406-201 62.6 27.0

CP-406-203 62.2 26.9

CP-406-206 115.1 36.6

CP-406-208 112.8 36.3

CP-406-211 86.2* 31.7

CP-406-213 91.0 32.6

CP-406-216 89.9 32.4

CP-406-218 56.0 25.6

CP-406-221 117.2 37.0

CP-406-223 125.7 38.3

CP-406-226 84.9 31.5

CP-406-228 93.1 32.9

CP-406-231 66.0 27.7

CP-406-233 90.7 32.5

CP-406-236 102.5 34.6

CP-406-238 99.1 34.0

CP-406-241 86.0 31.7

CP-406-243 93.4* 33.0

CP-406-246 78.0 30.1

CP-406-248 50.9 24.4

CP-406-251 108.4 35.5

CP-406-253 107.3 35.4

CP-406-256 86.3 31.7

CP-406-258 85.6 31.6

CP-406-261 67.8 28.1

CP-406-263 77.4 30.0

CP-406-266 118.7 37.2

CP-406-268 114.0 36.4

CP-406-271 86.5 31.7

CP-406-273 85.0 31.5

CP-406-276 59.1 26.2

CP-406-278 57.4* 25.9

M5

M6

M4

M3

M2

T-L

M1

L-T

T-L

S-T

L-T

T-L

S-T

L-T

T-L

S-T

L-T

S-T

S-T

L-T

T-L

S-T

L-T

T-L

* Not fully valid JIC value. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

131 of 223

NESC Request No.: TI-13-00884 

The composite fracture data is shown in Figure 10.3-2. This figure reflects all data taken from 

various locations across the aft bulkhead and is plotted for each orientation. Fracture toughness 

values vary with orientation as expected. Specifically, toughness in the L-T orientation is higher 

than toughness in the T-L orientation, which in turn is higher than toughness in the S-T 

orientation. 

Figure 10.3-2. Fracture Toughness Data as a Function of Orientation 

In order to examine trends in the toughness with respect to location within the aft bulkhead, plots 

were made along selected meridian angle and circumferential lines as shown in Figure 10.3-3 

through Figure 10.3-7. The first plot, shown in Figure 10.3-3, is a composite of all toughness 

data as a function of orientation and coupon blank ID. For each coupon blank, the local L-T 

orientation toughness exceeds the T-L and S-T toughness. In blanks M1, M4, M5, and M6, the 

T-L toughness exceeds the S-T toughness. However, in coupon blanks M2 and M3, the S-T 

toughness overlaps the T-L toughness. Note that in coupon blanks M1, M2, and M4, the S-T 

toughness values exhibit a range in values on the order of 20% of their average. Subsequent 

analysis of data did not identify a trend in the range as a function of coupon blank location. With 

respect to the range in values for the in-plane orientations, the local L-T toughness values and the 

T-L toughness values were tightly grouped. The largest range for the local in-plane toughness 

values was 4%. In general, the data reflect the local toughness pattern that the L-T toughness is 

greater than the T-L toughness, which is greater than the S-T toughness. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

132 of 223

NESC Request No.: TI-13-00884 

Toughness as a function of arc length distance for the 0o to 180o and 90o to 270o meridian angles 

is shown in Figure 10.3-4 and Figure 10.3-5, respectively. Along both meridian lines, the L-T 

orientation toughness shows a slight decrease in toughness from the pole to the rim. The T-L 

data appear to be uniform across the arc length of the aft bulkhead. The average S-T data exhibit 

a slight decrease in toughness along the arc length, although the scatter in the S-T data makes it 

difficult to conclusively describe the trend. The drop in L-T toughness from pole to rim is in 

contrast to the tensile data, but consistent with such trends in Al wrought products. 

Toughness as a function of the meridian angle for circumferential lines of 36-inch and 55-inch 

arc length is shown in Figure 10.3-6 and Figure 10.3-7, respectively. The L-T and T-L data are 

uniform. The S-T data also appear uniform, but again, the scatter in the data makes it difficult to 

definitively identify a trend. 

From a damage tolerance perspective, in each orientation, the toughness-to-YS ratios are greater 

than 60%. For structural designs limited by yield stress margins of safety, this translates into 

critical flaw sizes that should be readily detectable by conventional non-destructive evaluation 

techniques. 

The fracture toughness of Al alloys is sensitive to many metallurgical parameters, including 

grain size. Generally, larger grain size microstructures exhibit lower fracture toughness due to 

preferential fracture paths along large grain boundaries which are often populated by 

precipitates. The fracture toughness specimens used in this study were machined such that the 

crack extension region was centered about the mid-plane (t/2) of the aft bulkhead. The 

microstructure is less variable over the aft bulkhead at the mid-plane as compared with other 

through-thickness positions which likely contributed to the relatively uniform fracture toughness 

values. Additional testing is recommended in the large grain regions to assess the effect on 

fracture toughness. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

133 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-3. Fracture Toughness Data as a Function of Coupon Blank Location and Grain 

Orientation 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

134 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-4. Fracture Toughness Data as a Function of Arc Length Distance from Pole for the 

0° to 180° Meridian 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

135 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-5. Fracture Toughness Data as a Function of Arc Length Distance from Pole for the 

90° to 270° Meridian 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

136 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-6. Fracture Toughness Data as a Function of Meridian Angle for Arc Length Distance 

of 36 Inches 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

137 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-7. Fracture Toughness Data as a Function of Meridian Angle for Arc Length Distance 

of 55 Inches 

Another critical element in fracture behavior is the ability of the material to tear in a stable 

manner. This is generally measured in terms of the fracture toughness (J) versus crack extension 

(Δa) for the material. This is also known as the resistance or R-curve. The fracture specimens 

exhibited rising R-curves for all coupon blank locations and test orientations. This reflects 

ability of the material to tear in a stable manner after crack initiation. Specimens in the L-T 

orientation tended to have steeper R-curves than specimens in the S-T or T-L orientation. 

Steeper R-curves reflect greater ability to resist tearing (i.e., the material is less likely to 

experience unstable crack propagation) (24). Representative R-curves (J vs Δa) are shown in 

Figures 10.3-8 through 10.3-10. From a damage tolerance perspective, the combination of high 

toughness and rising R-curve behavior are very positive attributes for the material. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

138 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-8. J-R Curve for Spin Formed Al 2219-T62 Aft Bulkhead Material in the L-T 

Orientation; Coupon Blank M3, Specimen CP-406-223 

-0.01 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

0

20

40

60

80

100

120

140

160

180

200

'a (in)

J (in*lbs/in2

)

File:CP-406-223_T1 WO:2014-0061 Matl:2219-T62 Specimen:CP-406-223 Temp:72F

Jq = 126

Kjq = 38.3

All J-'a data

Valid J-'a data

J @ Pimax

JIc curve fit
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

139 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-9. J-R Curve for Spin Formed Al 2219-T62 Aft Bulkhead Material in the T-L 

Orientation; Coupon Blank M3, Specimen CP-406-228 

-0.01 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

0

20

40

60

80

100

120

140

160

180

200

'a (in)

J (in*lbs/in2

)

File:CP-406-228_T1 WO:2014-0061 Matl:2219-T62 Specimen:CP-406-228 Temp:72F

Jq = 93

Kjq = 32.9

All J-'a data

Valid J-'a data

J @ Pimax

JIc curve fit
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

140 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-10. J-R Curve for Spin Formed Al 2219-T62 Aft Bulkhead Material in the S-T 

Orientation; Coupon Blank M3, Specimen CP-406-233 

F-4. Fracture toughness was uniform with location in the aft bulkhead and indicated excellent 

damage tolerance capability. 

x In-plane (T-L and L-T) toughness values are relatively constant for a given 

orientation and do not vary significantly across the aft bulkhead acreage. 

x Through-thickness (S-T) toughness appears uniform as well, but exhibits 

significant data scatter for a given bulkhead location. 

x Spin formed 2219-T62 aft bulkhead material exhibited rising R-curve for all 

orientations and locations and toughness-to-YS ratios in excess of 60%. 

x High toughness values, high toughness-to-YS ratios, and rising R-curve behavior 

suggest excellent damage tolerance capability for the spin formed Al 2219-T62 

aft bulkhead material. 

10.3.2 Fractography 

Photomicrographs of typical fracture surfaces from compact tension fracture specimens tested in 

the T-L, L-T, and S-T orientations are shown in Figure 10.3-11 - Figure 10.3-13. For the T-L 

and L-T orientations (Figure 10.3-11 and Figure 10.3-12), the tearing region is relatively flat and 

-0.01 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

0

20

40

60

80

100

120

140

160

180

200

'a (in)

J (in*lbs/in2

)

File:CP-406-233_T1 WO:2014-0061 Matl:2219-T62 Specimen:CP-406-233 Temp:76F

Jq = 91

Kjq = 32.5

All J-'a data

Valid J-'a data

J @ Pimax

JIc curve fit
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

141 of 223

NESC Request No.: TI-13-00884 

uniform. Conversely, the tearing region for the S-T specimen (Figure 10.3-13) is more irregular 

and exhibited more topography than the T-L and L-T regions. 

Figure 10.3-11. Photomicrograph of Fracture Surface of T-L Fracture Specimen from Coupon 

Blank M2 

Figure 10.3-12. Photomicrograph of Fracture Surface of L-T Fracture Specimen from Coupon 

Blank M2 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

142 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-13. Photomicrograph of Fracture Surface of S-T Fracture Specimen from Coupon 

Blank M2 

10.3.3 Comparison with Handbook Data and Other T6 and T8 Products 

A comparison of fracture toughness behavior between the spin formed Al 2219-T62 aft bulkhead 

material and Al 2219-T87 plate material in three grain orientations is shown in Figure 10.3-14 

(25). As shown in the plot, on average, the spin formed material exhibits higher toughness 

values than the plate material for each of the orientations. Limited additional data in the T-L 

orientation was obtained for Al 2219-T62 plate and Al 2219-T851 plate. The data is shown in 

Figure 10.3-15 (25). Data for Al 2219-T87 plate is repeated from Figure 10.3-14. The T62 spin 

formed aft bulkhead material toughness is comparable to the toughness in the T62 and T851 

plate material. As noted earlier, the T62 spin formed aft bulkhead material toughness is higher 

than the toughness in the T87 plate material. For the most part, this behavior can likely be 

attributed to the general behavior of 2000 series Al alloys that reflect an increase in fracture 

toughness with a decrease in YS (26). In general, per MMPDS-08 (17), the A-Basis YSs for 

Al 2219–T87 temper is higher than the T851 temper which is higher than the T62 temper. 

The fracture parameter KJIC was used in this study to evaluate the fracture toughness of the 

Al 2219-T6 aft bulkhead. To more fully evaluate damage tolerance fracture toughness with preexisting surface flaws and fatigue crack, growth rate should be determined. Such damage 

tolerance testing would typically be required before using a material in fracture critical pressure 

vessel or structural applications. Crack growth rate testing (27) would provide data to support 

safe-life assessments based on assumed or NDE based initial flaw sizes. Surface crack 

toughness testing (28) would provide critical stress intensity data required to evaluate partthrough crack toughness of the material. Surface crack and crack growth rate data could be used 

to evaluate leak or burst behavior of the structure. Collectively, this data could be used to assess 

damage tolerance of hardware as outlined in NASA-STD-5019, “Fracture Control Requirements 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

143 of 223

NESC Request No.: TI-13-00884 

for Spaceflight Hardware (29),” and the American Petroleum Institutes’ “Recommended Practice 

579 – Fitness-For-Service (30).”

F-5. The fracture toughness of the spin formed Al 2219-T62 aft bulkhead material was typical 

for established 2219-T62 products. 

x Fracture toughness values exhibited the typical variation with orientation: L-T 

orientation > T-L orientation > S-T orientation. 

x Fracture toughness was in-family with conventional Al 2219 Al tempers and 

product forms. Toughness values were comparable to Al 2219-T62 and T851 

plate and are greater than for T87 plate, which is consistent with the tensile 

strength being lower than for T87 plate. 

O-2. Limited data was available in handbooks or open literature publications for Al 2219-T6 

material for comparison with the aft bulkhead properties, consequently it was difficult to 

assess the aft bulkhead in the context of other commercial Al 2219-T6 products. 

x Fracture toughness data was only available in handbooks and open literature 

publications for Al 2219-T6 and –T8 plate. No fracture toughness data was 

publicly available for 2219 spin formed products. 

O-3. Fracture toughness data suggests excellent damage tolerance in the 2219-T6 spin formed 

material; however, surface crack tension and da/dN testing is necessary to more fully 

characterize damage tolerance. 

R-2. Additional testing should be performed on first article and initial serial production aft 

bulkhead components to generate data to populate the material property database for Al 

2219-T6 spin formed products. (O-2) 

x Fracture testing should generate data to more substantially populate the KJIc

fracture toughness database. 

R-3. Perform surface crack tension fracture toughness and fatigue crack growth rate (da/dN) 

testing in order to fully characterize damage tolerance. (O-3)
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

144 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-14. Fracture Toughness Comparison between Spin Formed Al 2219-T62 Aft Bulkhead 

Material and Al 2219-T87 Plate (25) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

145 of 223

NESC Request No.: TI-13-00884 

Figure 10.3-15. Fracture Toughness Comparison between Spin Formed Al 2219-T62 Aft Bulkhead 

Material and other Al 2219 Tempers in the T-L Orientation (25) 

10.4 SCC Test Results 

Figure 10.4-1 shows the aft bulkhead cut plan with the location of coupon blanks from which 

specimens were excised for SCC testing highlighted in yellow. Table 10.4-1 shows the size and 

location of these coupon blanks with respect to the original plate rolling direction and distance 

from the aft bulkhead pole to the coupon blank center point. These coupon blank locations were 

designed to determine uniformity of SCC properties throughout the aft bulkhead and were 

evaluated along selected meridian and circumferential lines. 

An additional goal of these tests was to determine how these properties compare to wrought plate 

in the T6 and T8 tempers and to other fabricated product forms in the T62 temper. These results 

will assist the Orion designers in assessing the attributes of the spin form fabrication process for 

the aft bulkhead and identify any deficiencies or “show stoppers” associated with this fabrication 

process. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

146 of 223

NESC Request No.: TI-13-00884 

Figure 10.4-1. Aft Bulkhead Cut Plan showing the Location of the SCC Coupon Blanks highlighted 

in Yellow 

Table 10.4-1. SCC Coupon Blank Locations and Orientations 

Coupon 

Blank 

Longitudinal 

Dimension, 

in. 

Transverse 

Dimension, 

in. 

Meridian 

Angle, 

degrees 

Center Point 

Arc Length, 

in. 

M7 14 12 90° 12.00 

M8 14 12 90° 35.13 

M9 14 12 90° 56.25 

M10 14 12 190° 35.63 

10.4.1 Alternate Immersion Test Results 

10.4.1.1 30-day Alternate Immersion Exposure Test Results 

The tests results for the 30-day alternate immersion exposure SCC testing are shown in 

Table 10.4-2. The baseline tensile data used to establish the applied stress levels for the SCC 

tests is shown in Table 10.4-3. 

LT Specimens: 

No SCC failures occurred in the LT specimens after 30-day alternate immersion exposure, even 

at 90% YS applied stress levels (Table 10.4-2). One of the three replicate specimens from each 

test group was metallographically examined. Representative photomicrographs at 0 and 90% YS 

applied stress levels are shown in Figure 10.4-2 through Figure 10.4-5. One 90% YS LT 

specimen from coupon blank M8 appears to be cracked, as can be observed in specimen #54 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

147 of 223

NESC Request No.: TI-13-00884 

(Figure 10.4-3). The 50% and 75% YS LT specimens, although not shown in the figures, did not 

show cracks. 

The remaining two replicate specimens from each test group were tensile tested to determine 

residual tensile strength remaining after exposure; the results are presented in Table 10.4-4 - 

Table 10.4-7. The percent tensile strength retained (defined in Section 8.5) ranged from 42 to 

71% for the LT specimens. The residual strength ratio (also defined in Section 8.5) for each LT 

specimen exceeded 0.75, which was defined as the minimum value required to be considered a 

passing test. 

ST Specimens: 

Eighteen SCC failures occurred in the reduced section of the ST specimens within 30 days of 

alternate immersion exposure to 3.5% NaCl (Table 10.4-2). The failures can be divided into 

groups as follows: 

x Nine failures occurred out of 12 specimens tested at 90% YS; three from coupon blank 

M7, two from M8, one from M9, and three from M10. 

x Eight failures out of 12 specimens tested at 75% YS; three specimens from coupon blank 

M7, three from coupon blank M8, none from coupon blank M9, and two from coupon 

M10. 

x One failure out of 12 specimens tested at 50% YS; one from coupon blank M10. 

Metallographic examinations were performed on ST specimens that failed and the control ST 

specimens that were exposed without stress. Significant pitting corrosion was observed (Figure 

10.4-2 - Figure 10.4-5). In addition to pitting, intergranular cracks were also observed on several 

ST specimens that failed. The cracks were more prominent on the 75 and 90% YS ST 

specimens, although intergranular cracking was observed on - one 50 % YS specimen. 

Examples of the most visible cracks are shown in Figure 10.4-2 (specimens #29 (75% YS) and # 

34 (90% YS)); Figure 10.4-3 (specimen #73 (75% YS)); and Figure 10.4-5 (specimen #157 (75% 

YS)). The 50% YS ST specimen that failed in 29 days (Figure 10.4-5, specimen #152) showed 

intergranular attack, which is associated with stress corrosion on Al alloys. As was the case for 

all specimens tested, pitting corrosion was also present. This was the only 50% YS specimen 

that failed within a 30-day period. The 0% YS control ST specimens and the non-failed 50% YS 

ST specimens were metallographically examined and did not show evidence of SCC. Based on 

the tabulated data shown in Table 10.4-2 and the metallographic examination, the ST specimens 

furthest from the pole (coupon blank M9) appear to be less prone to SCC than the other regions 

The residual tensile strength values for the LT and ST specimens that survived the 30 day 

alternate immersion exposure in 3.5% NaCl are shown in Table 10.4-4 through Table 10.4-7. 

All of the LT specimens passed the residual strength criteria test of ! 0.75. The percent tensile 

strength retained for the ST specimens was significantly less than that of the LT specimens. All 

of the ST specimens passed except those from coupon blank M10 stressed at 50% YS (see 

Table 10.4-7). Specimen 153 (50% YS) had a ratio of 0.29 and specimen 154 (50% YS) had a 

ratio of 0.13. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

148 of 223

NESC Request No.: TI-13-00884 

It can be observed from the data that the SCC susceptibility of the material varied with the aft 

bulkhead location from which the coupon blanks were obtained. Based on the 30-day alternate 

immersion results, the proposed SCC ratings per MSFC-3029 (Tables I, II, or III) for different 

coupon blank locations and the corresponding rationale are presented in Table 10.4-8. The aft 

bulkhead rim region represented by coupon blank M9 was found the most resistant to SCC 

(Table I). Pole and membrane regions represented by coupon blanks M7 and M8, respectively, 

were found moderately resistant (Table II), and the membrane region represented by coupon 

blank M10 was the least resistant (Table III). 

10.4.1.2 90-day Alternate Immersion Exposure Test Results 

The test results for the 90-day alternate immersion exposure in 3.5% NaCl are presented in Table 

10.4-9. The baseline tensile data used to establish the applied stress levels for the SCC tests is 

shown in Table 10.4-3. Half of the LT specimens and all but one of the ST specimens failed 

during the 90-day exposure. All the ST specimens stressed to 75% YS failed within the range of 

26 to 85 days. Failures also occurred in the LT specimens stressed to 75% YS within the range 

of 70 to 90 days; two from coupon blank M7, two from coupon blank M8, and three from 

coupon blank M10. Many ST and LT control specimens (0% YS) failed due to general corrosion 

within the range of 48 to 90 days. Eleven of them were from the ST direction and five from the 

LT direction. 

Tensile tests were performed on the surviving specimens to determine residual strength; the 

results are presented in Table 10.4-10. The percent strength retained for the 90-day alternate 

immersion exposure specimens ranged from 11 to 45%. Most specimens that survived the 

90-day SCC exposure test show extremely low load carrying capability. 

Metallographic views of representative failed ST and LT specimens are presented in 

Figure 10.4-6. All failed specimens exhibited severe pitting corrosion with some intergranular 

cracking. 

The severe pitting corrosion and low load carrying capability suggest that the 90-day exposure to 

3.5% NaCl is too long and not suitable for the spin formed Al 2219-T62 aft bulkhead material. 

The 3.5% NaCl alternate immersion exposure should be limited to 30 days. In addition, 

corrosion protection for this material should be considered when exposed to corrosive 

environments. 

10.4.1.3 Discussion of Alternate Immersion Exposure Test Results 

Two of the ST specimens in the 90-day test matrix exposed at 75% of the YS failed before 

30 days; consequently, the two data sets were combined and evaluated as 30-day exposure tests. 

The combined test results show that twenty SCC failures occurred out of a total of 48 ST 

specimens tested within 30 days of alternate immersion exposure to 3.5% NaCl. The failures can 

be divided into groups as follows: 

x Nine failures occurred out of 12 specimens tested at 90% YS; three from coupon blank 

M7, two from M8, one from M9, and three from M10. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

149 of 223

NESC Request No.: TI-13-00884 

x Ten failures occurred out of 24 specimens tested at 75% YS; four specimens from coupon 

blank M7, three from coupon blank M8, none from coupon blank M9, and three from 

coupon M10. 

x One failure out of 12 specimens tested at 50% YS; one from coupon blank M10. 

Results from the 30-day exposure tests for specimens exposed at 75% YS and lower are used to 

establish SCC rankings and table ratings so it is this combined data set that is of primary interest. 

The ST results have raised some concern and prompted much discussion. Failures occurred in 

all four locations in the aft bulkhead at the highest exposure stress level (90% of YS) and in most 

locations when exposed at 75% YS. One specimen failed during exposure at 50% YS. 

Metallography confirmed that this was an SCC failure and was not due to general corrosion. The 

significance of the 50% YS stress level failure is that (1) the rating will be Table III, and (2) the 

design allowable stress level will need to be reduced. The resulting table ratings are provided 

and explained in Table 10.4-7. 

F-6. The SCC resistance of the spin formed 2219-T6 material varied with location in the aft 

bulkhead and in some locations exhibited lower resistance than previously established for 

2219-T6 material. 

x Regions near the pole exhibited moderate resistance to SCC (Table II per MSFC3029), near the rim a high resistance to SCC (Table I), and one of the areas in the 

membrane a low resistance to SCC (Table III). 

x The LT orientation appeared to be significantly more resistant to SCC than the ST 

orientation. Residual strength after exposure was significantly higher for LT 

specimens than ST specimens.

x The 90-day alternate immersion exposure appears to be too long for the spin 

formed 2219-T62 material since failures can occur by corrosion mechanisms 

(general and pitting corrosion) different than those for SCC, which can interfere 

with the SCC evaluation.

10.4.2 Salt Spray Test Results 

10.4.2.1 30-day Salt Spray Exposure Test Results 

The test results for the L specimens from coupon blank M10 exposed to 5% salt spray are 

presented in Table 10.4-11. The baseline tensile data used to establish the applied stress levels 

for the SCC tests is shown in Table 10.4-3. None of the specimens exposed to salt spray and 

stressed to 0% and 75% YS failed. 

Post exposure tensile testing was performed to determine residual strength. The results are 

presented in Table 10.4-13. The percent tensile strength retained for the 30-day salt spray 

exposure specimens ranged from 93 to 98% which is significantly greater than the specimens 

exposed for 30 days to 3.5% NaCl alternate immersion (see Table 10.4-4 through Table 10.4-7). 

The superior SCC resistance for the 30-day salt spray testing is likely related to the inherently 

better SCC resistance in the L orientation. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

150 of 223

NESC Request No.: TI-13-00884 

10.4.2.2 90-day Salt Spray Exposure Test Results 

The test results for the L specimens from coupon blank M10 exposed to 5% salt spray are 

presented in Table 10.4-12. The baseline tensile data used to establish the applied stress levels 

for the SCC tests is shown in Table 10.4-3. None of the specimens exposed to salt spray and 

stressed to 0%, 50%, 75%, and 90% YS failed. 

Post exposure tensile testing to determine residual strength was performed; the results are 

presented in Table 10.4-13. The percent tensile strength retained for the 90-day salt spray 

exposure specimens ranged from 90 to 97%. These specimens retained significantly more of the 

initial strength than the specimens that survived 90 day 3.5% NaCl alternate immersion exposure 

(Table 10.4-9). The improved SCC results of the 90-day salt spray testing is likely related to the 

inherently better SCC resistance in the L orientation. 

10.4.3 Comparison with Handbook Data and Other T6 and T8 Products 

There is little SCC data available in open literature publications for Al 2219-T6 products in 

general and none for spin formed components. A review of the available literature for Al 2219-

T6 material suggests excellent SCC properties for this material. This is in stark contrast to the 

SCC ratings determined for the aft bulkhead material in various locations. However, a closer 

examination of the data and sources reveals that the SCC ratings for Al 2219-T6 were either 

poorly documented, assumed based on testing of other tempers and exposure conditions, or were 

based on non-standardized test methodologies. Many of these studies were from the 1960’s and 

were conducted prior to the established ASTM G44 standard practice for alternate immersion 

testing. 

Alcoa Green Letters 176 and 188 indicate excellent resistance to SCC for Al 2219 in the T62, 

T6, T81, T851, and T87 tempers, but also indicates that non-standard aging treatments may 

decrease the resistance of Al 2219 to an unsatisfactory level (31), (32). Similar ratings were 

published in MSFC-STD-3029. ASTM G64 states that 2219-T6 products do not have an 

assigned rating because the product is not offered commercially (33). However, no specific test 

data was published in these summary level reports so the sources were reviewed to determine 

possible explanations for the discrepancy in SCC ratings. 

NASA-CR-88110 (1966-10-06, prepared by Alcoa under contract NAS 8-5340) (34) indicates 

that rolled rod of alloy 2219-T62 demonstrated immunity to SCC in seacoast and industrial 

atmosphere when stressed to 75% of the actual YS. Table III of that documents shows no 

failures out of 5 specimens stressed to 75% YS and exposed to alternate immersion for 84 days. 

It must be mentioned that when that test was performed the alternate immersion test method had 

not been standardized, and Alcoa used tap water when preparing the test solutions for testing 

2219-T62. In a meeting that took place at Alcoa and that was documented in Memo 3-4820-194 

(on a letter to Alcoa) it was concluded that tap water was causing Alcoa results to be better than 

results obtained in other laboratories because pH tends to be higher when tap water is used (35). 

The MSFC STD 3029 uses deionized water when preparing the 3.5% NaCl solution to comply 

with ASTM G44. That may explain the lower SCC performance of 2219-T62 material from the 

aft bulkhead when compared to the Alcoa study. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

151 of 223

NESC Request No.: TI-13-00884 

NASA-CR-155461 (1964-08-14, prepared by Alcoa under contract NAS 8-5340) indicates on 

page two that 2219-T62 would be expected to have a high degree of resistance to SCC (36). A 

Chapter Prepared for ARPA Handbook (1976-00-00, SCC of Al Alloys, Speidel, Ohio State 

University) indicates a SCC threshold for 2219-T62 plate in the ST direction of 32 ksi (37). 

The Al 2219-T62 literature search suggests excellent SCC properties for this material. Highly 

susceptible Al alloys usually start failing within the first or second week of exposure. In the 

alternate immersion testing of the aft bulkhead material, the specimens survived several weeks of 

exposure before failures started to occur. This suggests that even though the Al 2219-T62 aft 

bulkhead material is not highly resistant to SCC, it is not highly susceptible either, when 

compared to other tempers, such as T3 or T4. It appears that the tests performed on this material 

in the 1960’s were performed when the technique had not been standardized and rendered a 

slightly elevated rating. It also seems that the excellent results from seacoast and industrial 

atmospheres had a significant weighting on the established rating. Based on the paucity of 

relevant SCC data, the NESC team recommends that Orion conduct further SCC testing of the Al 

2219-T62 aft bulkhead material to establish SCC ratings as well as SCC threshold levels. 

SCC data on Al-Li 2195-T8 and Al 2219-T87 wrought plate is presented in Table 10.4-14 for 

comparison. These data were generated at MSFC and most of it was reported in MSFC Memos 

EH24 (94-107) and EH24 (95-57) (38), (39). Based on the 30-day SCC rating criteria in MSFCSTD-3029, Al-Li 2195-T8 material can be assigned at Table II rating and Al 2219-T87 material 

a Table I rating. The rationale for these ratings is shown in Table 10.4-15. Although Al-Li 

2195-T8 material met Table II requirements of 30 days exposure at 50% YS with no failures, a 

failure did occur after 31 days, which is not too far from the 29 days to failure for the spin 

formed Al 2219-T62 aft bulkhead material stressed at 50% YS. It can also be noticed that the 

Al-Li 2195 specimens stressed to 75% and 90% YS, in general, failed in a shorter time than the 

Al 2219-T62 specimens. 

For Al 2219-T87 (a Table I material) tested in the ST orientation, the 75% YS failures started to 

occur after 38 days and the 50% YS failures after 41 days. Failures in the ST orientation for the 

Al 2219-T62 aft bulkhead material began after 26 days for the 75% YS exposures and the one 

failure at 50% YS occurred after 29 days exposure. This indicates that the spin formed Al 2219-

T62 aft bulkhead material has inferior SCC properties compared to Al 2219-T87 material based 

on the 30-day alternate immersion exposure tests. 

For Al-Li 2195-T8 (a Table II material) tested in the ST orientation, the 75% YS failures started 

to occur after 11 and 27 days depending on heat treatment and the 50% YS failures after 31 days. 

This indicates that the spin formed Al 2219-T62 material has comparable SCC properties to AlLi 2195-T8 material based on the 30-day alternate immersion exposure tests. 

O-2. Limited data was available in handbooks or open literature publications for Al 2219-T6 

material for comparison with the aft bulkhead properties, consequently it was difficult to 

assess the aft bulkhead in the context of other commercial Al 2219-T6 products. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

152 of 223

NESC Request No.: TI-13-00884 

x The SCC data for the aft bulkhead provides insight about the SCC resistance of 

spin formed 2219-T62 material, but is insufficient to establish a threshold stress 

level. 

10.4.4 Discussion of Stress Corrosion Results 

SCC tests were performed on material from four coupon blank locations in the aft bulkhead 

corresponding to the rim (M9), membrane (M8), and pole (M7) along the 90° meridian line, and 

a second membrane region (M10) located along the 180° meridian line. Both LT and ST 

orientations were tested using alternate immersion and salt fog for either 30 or 90 day exposures. 

There were no failures during the salt fog tests and the 90-day alternate immersion results are 

clouded by general corrosion problems. 

The primary data of interest are the 30-day alternate immersion exposure since results from this 

test method and exposure time are typically the basis for handbook and table ratings of SCC 

resistance. No failures occurred for the LT orientation, even at the highest stress levels, and all 

specimens had passing post-exposure residual strength levels. The ST results raise some 

concern. Failures occurred in all four locations in the aft bulkhead at the highest exposure stress 

level (90% of YS) and in most locations when exposed at 75% YS. One specimen failed during 

exposure at 50% YS. Metallography confirmed that this was an SCC failure and was not due to 

general corrosion. The significance of the 50% YS stress level failure is that (1) the rating will 

be Table III, and (2) the design allowable stress level will need to be reduced. (See Table 10.4-8 

for an explanation of the ratings). For comparison, Al 2219-T8 material is rated Table I and AlLi 2195-T8 is Table II (see Table 10.4-15). 

There are some important points to make regarding this data. The aft bulkhead tests followed 

MSFC test standard MSFC-STD-3029 in which the exposure stress levels are based on the 

measured strength of the material. Handbook values are based on standards that use MMPDS Abasis allowable strengths for plate to determine applied stress levels. Actual strength is always 

higher than the allowables due to statistical knockdown; consequently the aft bulkhead 

specimens were exposed at higher stress levels than handbook data being used for comparison. 

In addition, since there are no allowables for the ST orientation for 2219-T6 plate, standards that 

base exposure stress on allowables use the L orientation allowables regardless of the orientation 

of the SCC specimen. For the aft bulkhead SCC testing, the ST YS was used to determine the 

exposure stress. The ST YS was 10% greater than the L YS, which further contributed to the 

high exposure stress levels. 

An additional caveat for these test results is the test duration as specified in MSFC-STD-3029. 

One disadvantage of the accelerated laboratory 3.5% NaCl alternate immersion test is that severe 

pitting may develop in the test specimens. As per ASTM G47, such pitting in tensile specimens 

with relatively small cross-sections can markedly reduce the effective cross-sectional area and 

result in net sectional stresses greater than nominal gross section stress. This end result is that 

the pitting may interfere with the valid evaluation of the SCC resistance of the material. For this 

reason, ASTM G47 and G64 recommend a 10 day alternate immersion exposure period for 2xxx 

series Al alloys when tested in the ST orientation and a 40-day exposure period when tested in 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

153 of 223

NESC Request No.: TI-13-00884 

the L and LT orientations. These exposure periods are believed to be long enough to detect 

susceptibility to intergranular SCC yet short enough to avoid excessive pitting that can lead to 

failure by another mechanism. General pitting, which served as initiation sites for SCC, was 

noted in the aft bulkhead material following 30-day alternate immersion exposure. The NESC 

team recommends that further evaluation of the aft bulkhead material be evaluated at shorter 

exposure times. 

For alloys requiring microstructural control to avoid susceptibility to SCC, resistance is obtained 

by using heat treatments that produce uniform precipitation throughout the microstructure. The 

susceptibility of the Al 2219 aft bulkhead material to SCC is further exacerbated by the T62 

temper which results in a non-uniform distribution of precipitates. Because of the pitting 

potential of this material and a susceptible heat treat temper to SCC, deployment of this material 

for the aft bulkhead may require a MUA prior to acceptance for service. 

Alternative explanations for the reduced SCC resistance are that (1) the spin forming process has 

a negative effect, (2) the SCC properties are typical for T62 temper plate, and (3) that the 

reduced quench rate associated with the glycol/water mixture reduces the SCC resistance. 

Metallurgical theory recognizes that variations in thermal treatments, such as solution heat 

treatment, quenching, and aging treatment can have marked effects on the SCC resistance of 

2xxx series Al alloys. Ideally, all alloying elements should be fully dissolved during solution 

heat treatment, and the quench cooling rate should be rapid enough to keep them in solid 

solution. The quench medium for the spin formed aft bulkhead was a 15 to 17% polymer 

solution (see Section 7.8), which is intended to reduce distortion problems associated with water 

quenched Al alloys. Although this quench operation is permissible per AMS 2770, a sufficiently 

rapid quench rate might not be obtained because of the inherent cooling rate limitations of the 

polymer solution. The slower cooling rate affects the precipitation kinetics during subsequent 

aging and will lead to less uniform precipitation at and/or adjacent to the grain boundaries and 

hence this could lower the SCC resistance. Supplemental SCC testing, described in Section 11.3, 

will be performed in an attempt to answer these questions. Results of the supplemental testing 

will be provided in an addendum to this report. 

All SCC test specimens evaluated in this study were machined at the t/2 position through the 

thickness. The grain size varies less at t/2 with location in the aft bulkhead compared with other 

through-thickness positions and also represents an intermediate grain size. The SCC properties 

may be different in locations that have larger grain sizes. Generally, the larger grain size areas 

may be more prone to SCC than the smaller grain size areas because the larger grain size areas 

would require less energy for the crack to propagate. In order to determine to what extent the 

SCC susceptibility is higher in large grain size areas additional testing is recommended. 

Additional specimens should be obtained from the rim at the OML surface, which has been 

found to have very large grains in comparison to other areas. Successful completion of 

additional testing will add more confidence for the use of this material. 

While the SCC results provide insight into the material behavior, the data sets generated are very 

small and caution should be exercised in assigning table ratings. Additionally, the LM Orion 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

154 of 223

NESC Request No.: TI-13-00884 

design team will require definition of a threshold stress level for SCC to bracket service stress 

limits. There is not sufficient data in this study to define the threshold stress level for SCC. The 

NESC team recommends that additional SCC testing be performed on the first spin formed aft 

bulkhead articles fabricated for Orion to define the SCC threshold stress level. 

O-4. Questions arose regarding SCC test procedures, particularly the basis for exposure stress 

level and test duration, which may impact direct comparison of the aft bulkhead SCC 

results with the very limited handbook and open literature data. 

O-5. The SCC tests performed provided an initial indication of the SCC susceptibility of the 

spin formed 2219-T62 material; however, environmentally assisted fracture toughness 

(KEAC) and fatigue ((da/dN)SCC)) in the S-T orientation in a 3.5% NaCl environment is 

required to understand the impact of the SCC susceptibility on fracture and fatigue. 

O-6. The laboratory 30-day alternate immersion accelerated test condition provides adequate 

screening methodology for SCC; however, longer test durations of 90 days did lead to 

severe general corrosion and pitting. For determining actual serviceability of the 

material, other stress corrosion tests should be performed in the intended service 

environment. 

R-2. Additional testing should be performed on first article and initial serial production aft 

bulkhead components to generate data to populate the material property database for 

Al 2219-T6 spin formed products. (O-2) 

x Stress corrosion cracking testing should be continued until sufficient data is 

generated to establish the SCC threshold stress level. 

R-4. Exercise caution in using published handbook and table ratings for the SCC resistance of 

Al 2219-T6. Handbook and open literature publications should be reviewed in order to 

substantiate that the SCC test procedures and data generated are directly comparable to 

the MSFC-STD-3029 standard used in the SCC evaluation of the Al 2219-T62 aft 

bulkhead (O-4) 

R-5. Perform environmentally assisted fracture toughness (KEAC) and fatigue ((da/dN)SCC) 

tests in the S-T orientation in a 3.5% NaCl environment in order to understand the impact 

of the SCC susceptibility of the material on fracture toughness and fatigue. (O-5) 

R-6. Perform seacoast exposure SCC testing to characterize the corrosion performance of the 

aft bulkhead in the natural service environment. (O-6) 

 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

155 of 223

NESC Request No.: TI-13-00884 

Table 10.4-2. 30-day SCC test results for spin formed Al 2219-T62 aft bulkhead material. Test 

environment: 3.5% NaCl alternate immersion per ASTM G44. 

Coupon 

Blank 

Meridian 

Angle Orient. UTS ksi 

YS 

ksi 

Stress 

Level 

% YS 

Stress 

Level 

ksi 

Failure 

Ratio Days to Failure 

M7 90° 

LT 54.14 36.64 

0 0.00 0/3 No failures 

50 18.32 0/3 No failures 

75 27.48 0/3 No failures 

90 32.98 0/3 No failures 

ST 57.87 43.20 

0 0.00 0/3 No failures 

50 21.60 0/3 No failures 

75 32.40 3/3 26, 28, 30 

90 38.88 3/3 26, 26, 28 

M8 90° 

LT 57.79 38.78 

0 0.00 0/3 No failures 

50 19.39 0/3 No failures 

75 29.09 0/3 No failures 

90 34.90 0/3 No failures 

ST 58.69 43.73 

0 0.00 0/3 No failures 

50 21.87 0/3 No failures 

75 32.80 3/3 27, 30, 30 

90 39.36 2/3 26, 30 

M9 90° 

LT 59.58 39.68 

0 0.00 0/3 No failures 

50 19.84 0/3 No failures 

75 29.76 0/3 No failures 

90 35.71 0/3 No failures 

ST 59.86 44.33 

0 0.00 0/3 No failures 

50 22.17 1/3(2) 30(2)

75 33.25 0/3 No failures 

90 39.90 1/3 26 

M10 190° 

LT 55.89 37.87 

0 0.00 0/3 No failures 

50 18.94 0/3 No failures 

75 28.40 0/3 No failures 

90 34.08 0/3 No failures 

ST 59.65 44.41 

0 0.00 0/3 No failures 

50 22.21 1/3(3) 29 

75 33.31 2/3 26, 30 

90 39.97 3/3 29, 29, 30 (1)Exposure started on 3-5-2014 and ended on 4-4-2014. (2)Invalid failure. Failed in the shoulder (out of the gage length). (3)The two specimens that did not break apart during exposure did not pass the residual tensile strength ratio test and can also be considered failures.
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

156 of 223

NESC Request No.: TI-13-00884 

Table 10.4-3. Baseline tensile properties of spin formed Al 2219-T62 aft bulkhead material. Data is 

the average of three replicate tests and was used to establish stress levels for the SCC tests. 

Coupon 

Blank 

Meridian 

Angle Orient. UTS, 

ksi 

YS, 

ksi 

e, 

% 

RA, 

% 

E, 

Msi 

M7 90° 

LT 54.14 36.64 10.58 17.42 9.97 

ST 57.87 43.20 4.80 6.51 9.89 

M8 90° 

LT 57.79 38.78 9.79 9.52 10.48 

ST 58.69 43.73 4.57 9.89 9.66 

M9 90° 

LT 59.58 39.68 8.79 16.82 10.31 

ST 59.86 44.33 4.12 6.54 9.26 

M10 190° 

LT 55.89 37.87 10.15 17.15 10.14 

ST 59.65 44.41 4.83 6.57 10.12 

L 57.05 38.26 12.74 25.78 10.30 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

157 of 223

NESC Request No.: TI-13-00884 

Figure 10.4-2. Photomicrographs of Representative SCC Specimens obtained from Coupon Blank 

M7 following 3.5% NaCl Alternate Immersion Exposure (30-day test) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

158 of 223

NESC Request No.: TI-13-00884 

Figure 10.4-3. Photomicrographs of Representative SCC Specimens obtained from Coupon Blank 

M8 following 3.5% NaCl Alternate Immersion Exposure (30-day test) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

159 of 223

NESC Request No.: TI-13-00884 

Figure 10.4-4. Photomicrographs of Representative SCC Specimens obtained from Coupon Blank 

M9 following 3.5% NaCl Alternate Immersion Exposure (30-day test) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

160 of 223

NESC Request No.: TI-13-00884 

Figure 10.4-5. Photomicrographs of Representative SCC Specimens obtained from Coupon Blank 

M10 following 3.5% NaCl Alternate Immersion Exposure (30-day test) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

161 of 223

NESC Request No.: TI-13-00884 

Table 10.4-4. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead Material 

following a 30-Day Exposure to 3.5% NaCl Alternate Immersion per ASTM G44 

Bulkhead location: coupon blank: M7; meridian angle: 90°; arc length: 12.00 inches 

(1) UTSs = residual strength of stressed and exposed specimen 

UTS0 = averaged residual strength of non-stressed and exposed specimens 

(2) Passed if ratio≥0.75, failed if ratio <0.75. The 90% YS data is not used for the ratings, but 

is presented for information. 

Residual (1)

Initial Stress Stress Residual % Strength Pass/Fail (2)

UTS, Specimen Level, Level, UTS, Strength Ratio UTS Ratio

Orient. ksi Number % YS ksi ksi Retained UTSs/UTSo Test

LT 54.14 CP-406-3 0 0.00 28.23 52 NA NA

CP-406-4 0 0.00 30.98 57 NA NA

Avg: 29.61 54.5

CP-406-6 50 18.32 22.75 42 0.77 passed

CP-406-7 50 18.32 29.65 55 1 passed

CP-406-9 75 27.48 31.53 58 1.06 passed

CP-406-10 75 27.48 25.62 47 0.87 passed

CP-406-13 90 32.98 28.51 53 0.96 passed

CP-406-14 90 32.98 25.04 46 0.85 passed

ST 57.87 CP-406-24 0 0.00 28.40 49 NA NA

CP-406-25 0 0.00 18.61 32 NA NA

Avg: 23.51 40

CP-406-27 50 21.60 22.51 39 0.96 passed

CP-406-28 50 21.60 20.97 36 0.89 passed
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

162 of 223

NESC Request No.: TI-13-00884 

Table 10.4-5. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead Material 

following a 30-Day Exposure to 3.5% NaCl Alternate Immersion per ASTM G44 

Bulkhead location: coupon blank: M8; meridian angle: 90°; arc length: 35.13 inches 

(1) UTSs = residual strength of stressed and exposed specimen 

UTS0 = averaged residual strength of non-stressed and exposed specimens 

(2) Passed if ratio≥0.75, failed if ratio <0.75. The 90% YS data is not used for the ratings, but 

is presented for information.

Residual (1)

Initial Stress Stress Residual % Strength Pass/Fail (2)

UTS, Specimen Level, Level, UTS, Strength Ratio UTS Ratio

Orient. ksi Number % YS ksi ksi Retained UTSs/UTSo Test

LT 57.79 CP-406-45 0 0.00 33.98 59 NA NA

CP-406-46 0 0.00 33.23 58 NA NA

Avg: 33.60 58.5

CP-406-48 50 19.39 32.54 56 0.97 passed

CP-406-49 50 19.39 32.68 57 0.97 passed

CP-406-51 75 29.09 37.74 65 1.12 passed

CP-406-52 75 29.09 31.38 54 0.93 passed

CP-406-55 90 34.90 32.84 57 0.98 passed

CP-406-56 90 34.90 37.41 65 1.11 passed

ST 58.69 CP-406-66 0 0.00 23.25 40 NA

CP-406-67 0 0.00 19.44 33 NA

Avg: 21.35 36.5

CP-406-69 50 21.87 16.52 28 0.77 passed

CP-406-70 50 21.87 32.45 55 1.52 passed

CP-406-77 90 39.36 22.51 38 1.05 passed
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

163 of 223

NESC Request No.: TI-13-00884 

Table 10.4-6. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead Material 

following a 30-Day Exposure to 3.5% NaCl Alternate Immersion per ASTM G44 

Bulkhead location: coupon blank: M9; meridian angle: 90°; arc length: 56.25 inches 

Residual (1)

Initial Stress Stress Residual % Strength Pass/Fail (2)

UTS, Specimen Level, Level, UTS, Strength Ratio UTS Ratio

Orient. ksi Number % YS ksi ksi Retained UTSs/UTSo Test

LT 59.58 CP-406-87 0 0.00 39.10 66 NA NA

CP-406-88 0 0.00 39.16 66 NA NA

Avg: 39.13 66

CP-406-90 50 19.84 38.96 65 1 passed

CP-406-91 50 19.84 40.50 68 1.04 passed

CP-406-93 75 29.76 39.58 66 1.01 passed

CP-406-94 75 29.76 42.41 71 1.08 passed

CP-406-97 90 35.71 34.08 57 0.87 passed

CP-406-98 90 35.71 39.06 66 1 passed

ST 59.86 CP-406-108 0 0.00 26.95 45 NA NA

CP-406-109 0 0.00 19.55 33 NA NA

Avg: 23.25 39

CP-406-110 50 22.17 28.09 47 1.21 passed

CP-406-112 50 22.17 19.66 33 0.85 passed

CP-406-114 75 33.25 24.50 41 1.05 passed

CP-406-115 75 33.25 27.58 46 1.19 passed

CP-406-118 90 39.90 24.62 41 1.06 passed

(1) UTSs = residual strength of stressed and exposed specimen. 

UTS0 = averaged residual strength of non-stressed and exposed specimens. 

(2) Passed if ratio≥0.75, failed if ratio <0.75. The 90% YS data is not used for the ratings, but 

is presented for information.
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

164 of 223

NESC Request No.: TI-13-00884 

Table 10.4-7. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead Material 

following a 30-Day Exposure to 3.5% NaCl Alternate Immersion per ASTM G44 

Bulkhead location: coupon blank: M10; meridian angle: 190°; arc length: 35.63 inches 

Residual (1)

Initial Stress Stress Residual % Strength Pass/Fail (2)

UTS, Specimen Level, Level, UTS, Strength Ratio UTS Ratio

Orient. ksi Number % YS ksi ksi Retained UTSs/UTSo Test

LT 55.89 CP-406-171 0 0.00 34.10 61 NA NA

CP-406-172 0 0.00 29.47 53 NA NA

Avg: 31.79 57

CP-406-174 50 18.94 31.51 56 0.99 passed

CP-406-175 50 18.94 29.44 53 0.93 passed

CP-406-177 75 28.40 34.70 62 1.09 passed

CP-406-178 75 28.40 32.52 58 1.02 passed

CP-406-181 90 34.08 30.03 54 0.94 passed

CP-406-182 90 34.08 34.24 61 1.08 passed

ST 59.65 CP-406-150 0 0.00 18.88 32 NA NA

CP-406-151 0 0.00 19.36 32 NA NA

Avg: 19.12 32

CP-406-153 50 22.21 5.51 9 0.29 failed

CP-406-154 50 22.21 2.56 4 0.13 failed

CP-406-155 75 33.31 20.32 34 1.06 passed

(1) UTSs = residual strength of stressed and exposed specimen 

UTS0 = averaged residual strength of non-stressed and exposed specimens 

(2) Passed if ratio≥0.75, failed if ratio <0.75. The 90% YS data is not used for the ratings, but is 

presented for information.
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

165 of 223

NESC Request No.: TI-13-00884 

Table 10.4-8. Rating of spin formed Al 2219-T62 aft bulkhead material per MSFC-STD-3029. 

Based on a 30-day exposure to 3.5% NaCl alternate immersion per ASTM G44. 

Coupon 

Blank 

Meridian 

Angle,

degrees

Arc Length 

from CL, 

in. Rating Rationale for Rating

M7 90° 12.00 Table II 4 out of 6 ST specimens failed at 75% YS within 

30 days of exposure (26, 26, 28, and 30 days) to 

3.5% NaCl alternate immersion. None out of 3 

ST specimens failed at 50% YS within 30 days 

of exposure. Residual tensile strength ratio 

(UTSs/UTS0) of the 50% YS specimens that 

survived and were tensile tested was greater than 

0.75 (see Table 10.4-4).

M8 90° 35.13 Table II 3 out of 6 ST specimens failed at 75% YS within 

30 days of exposure (27, 30, and 30 days) to 

3.5% NaCl alternate immersion. None out of 3 

ST specimens failed at 50% YS within 30 days 

of exposure. Residual tensile strength ratio 

(UTSs/UTS0) of the 50% YS specimens that 

survived and were tensile tested was greater than 

0.75 (see Table 10.4-5).

M9 90° 56.25 Table I No ST specimens failed at 75% YS within 30 

days of exposure to 3.5% NaCl alternate 

immersion. Residual tensile strength ratio 

(UTSs/UTS0) of the 75% YS specimens that 

survived and were tensile tested was greater than 

0.75 (see Table 10.4-6).

M10 190° 35.63 Table III 1 out of 6 ST specimen failed at 50% YS within 

30 days of exposure (29 days) to 3.5% NaCl 

alternate immersion. Residual tensile strength 

ratio (UTSs/UTS0) of the two 50% YS 

specimens that survived and were tensile tested 

was significantly less than 0.75 (0.29 and 0.13) 

(see Table 10.4-7).

Table I = A rating* = Highly resistant to SCC in a sodium chloride environment 

Table II = B rating = Moderately resistant to SCC in a sodium chloride environment 

Table III = C rating = Low resistance to SCC in a sodium chloride environment 

*A, B, C ratings based on ASTM G64 (33) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

166 of 223

NESC Request No.: TI-13-00884 

Table 10.4-9. 90-day SCC test results for spin formed Al 2219-T62 aft bulkhead material. Test 

environment: 3.5% NaCl alternate immersion per ASTM G44. 

UTS, YS,

ksi ksi % YS ksi

0 0 3/3(2) 48(2), 90(2)(5), 90(2)(5)

75 27.48 2/3 76, 90(5)

0 0 3/3(2) 54(2), 64(2), 89(2)

75 32.4 3/3 26, 33, 33

0 0 1/3(2)(5) 90(2)(5)

75 29.09 2/3(5) 90(5), 90(5)

0 0 3/3(2) 89(2), 90(2)(5), 90(2)(5) 

75 32.8 3/3 33, 64, 83(3)

0 0 1/3(2)(5) 90(2)(5)

75 29.76 0/3 No failures

0 0 2/3(2) 58(2)(4), 90(2)(5)

75 33.25 3/3 56, 64(3), 85

0 0 0/3 No failures

75 28.4 3/3 70, 74, 74

0 0 3/3(2) 70(2)(4), 89(2), 89(2)

75 33.31 3/3 26, 54, 70

59.86 44.33

Orient.

Failure

Ratio

Days to

Failure

M7 90°

LT 54.14 36.64

ST 57.87 43.2

Stress Level

M10 190°

LT 55.89 37.87

ST 59.65 44.41

Coupon

Blank

Meridian

Angle

M8 90°

LT 57.79 38.78

ST 58.69 43.73

M9 90°

LT 59.58 39.68

ST

(1)Exposure started on 3-5-2014 and ended on 6-3-2014. 

(2)Failed due to corrosion since this specimen was not loaded. 

(3)Failed in the shoulder, out of the reduced section. 

(4)Failed in 2 places. 

(5)Failed during disassembly. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

167 of 223

NESC Request No.: TI-13-00884 

Table 10.4-10. Residual Tensile Strength Data for Spin Formed Al 2219-T62 Aft Bulkhead 

Material following a 90-Day Exposure to 3.5% NaCl Alternate Immersion per ASTM G44 

Initial 

UTS,

Residual 

UTS, 

ksi % YS ksi ksi 

M7 LT 54.14 CP-406-20 75 27.48 15.6 29

M8 LT 57.79 CP-406-57 0 0 17.5 30

M8 LT 57.79 CP-406-58 0 0 13.1 23

M8 LT 57.79 CP-406-62 75 29.09 16.4 28

M9 LT 59.58 CP-406-100 0 0 20.7 35

M9 LT 59.58 CP-406-101 0 0 20.2 34

M9 LT 59.58 CP-406-102 75 29.76 13.7 23

M9 LT 59.58 CP-406-103 75 29.76 18.4 31

M9 LT 59.58 CP-406-104 75 29.76 25.6 43

M9 ST 59.86 CP-406-121 0 0 6.3 11

M10 LT 55.89 CP-406-183 0 0 6.0 11

M10 LT 55.89 CP-406-184 0 0 12.0 21

M10 LT 55.89 CP-406-185 0 0 25.2 45

Specimen 

Number

Stress Level % 

Strength 

Retained

Coupon 

Blank Orient.
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

168 of 223

NESC Request No.: TI-13-00884 

Figure 10.4-6. Photomicrographs of Representative SCC Specimens obtained from Various 

Coupon Blanks following 3.5% NaCl Alternate Immersion Exposure (90-day test) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

169 of 223

NESC Request No.: TI-13-00884 

Table 10.4-11. 30-day SCC test results for spin formed Al 2219-T62 aft bulkhead material. Test 

environment: 5% salt fog per ASTM B117. 

Coupon 

Blank 

Meridian 

Angle Orient. UTS ksi 

YS 

ksi 

Stress 

Level 

% YS 

Stress 

Level 

ksi 

Failure 

Ratio 

Days to 

Failure 

M10 190° L 57.05 38.26 

0 0 0/3 No failures 

75 28.70 0/3 No failures 

(1) Exposure started on 3-5-2014 and ended on 4-4-2014. 

Table 10.4-12. 90-day SCC test results for spin formed Al 2219-T62 aft bulkhead material. Test 

environment: 5% salt spray per ASTM B117. 

Stress Stress

Coupon Meridian UTS YS Level Level Days to 

Blank Angle ksi ksi % YS ksi Failure 

0 0 0/3 No failures

50 19.13 0/3 No failures

75 28.7 0/3 No failures

90 34.43 0/3 No failures

Orient.

Failure 

Ratio

M10 190° L 57.05 38.26

(1) Exposure started on 3-5-2014 and ended on 6-3-2014. 

Table 10.4-13. Residual tensile strength data for spin formed Al 2219-T62 aft bulkhead material 

following exposure to 5% salt spray per ASTM B117. 

Initial 

UTS,

Test 

Duration,

Residual 

UTS, 

ksi Days % YS ksi ksi 

CP-406-141 0 0 54.3 95

CP-406-142 0 0 55.8 98

CP-406-143 0 0 53.2 93

CP-406-144 75 28.7 53.3 93

CP-406-145 75 28.7 54.5 96

CP-406-146 75 28.7 54.6 96

CP-406-128 0 0 54.3 95

CP-406-129 0 0 54.5 96

CP-406-130 0 0 55.1 97

CP-406-131 50 19.13 51.5 90

CP-406-132 50 19.13 51.9 91

CP-406-133 50 19.13 52.7 92

CP-406-134 75 28.7 54.7 96

CP-406-135 75 28.7 53.7 94

CP-406-136 75 28.7 55.0 96

CP-406-138 90 34.43 54.5 96

CP-406-139 90 34.43 51.8 91

CP-406-140 90 34.43 53.5 94

L 57.05 90

M10

M10

L 57.05 30

Coupon 

Blank Orient. Specimen Number

Stress Level % 

Strength 

Retained
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

170 of 223

NESC Request No.: TI-13-00884 

Table 10.4-14. SCC Test Data for other 2xxx Series Al Alloys for Comparison (38), (39) 

Stress Stress

UTS, YS, Level, Level, Failure 

ksi ksi % YS ksi Ratio

50 37.1 4/4 31, 40, 41, 69

75 55.6 4/4 11, 12, 18, 31

90 66.7 4/4 11, 17, 17, 17

75 56.8 3/3 27, 30, 31

90 68.1 3/3 12, 17, 19

75 56.8 1/3 423

90 68.1 3/3 315, 454, 513

75 56.8 0/3 NF in 115 days

90 68.1 0/3 NF in 115 days

50 40.6 0/5 NF in 90 days

75 60.8 0/5 NF in 90 days

90 73 3/5 74, 88, 90

50 26 4/5 41, 52, 58, 62

75 39 4/5 38, 44, 48, 58, 62

50 26.2 0/5 NF in 90 days

75 39.3 2/5 90, 91

Test 

Environ. Days to Failure

2195-T8 

(1.7” thick plate)

290°F/20h ST 89.1

Alloy Heat 

Treatment

Orient.

290°F/16h ST 86.2 74.1 Alt. Imm.

75.7

Alt. Imm.

KSC 

Seacoast

High Hum.

LT 86.4 81.1 Alt. Imm. 2195-T8 

(0.32” thick plate) 320°F/20h

60.7

2219-T87 

(4” thick plate) 350°F/18h

LT 66.4 52.4

ST1 

(midthick.)

12/12 20, 28, 30, 31, 33, 46, 

49, 64, 73, 76, 81, 87 ST Alt. Imm. 1 (edge) 63.5 53.3 90 48

52

(1)The 2219 ST specimens tested at 50% and 75% YS were obtained from the plate mid-thickness whereas the ST 

specimens tested at 90% YS were obtained from the plate edge. 

Table 10.4-15. Rating of Al 2195-T8 and Al 2219-T87 per MSFC-STD-3029. Based on a 30-day 

exposure to 3.5% NaCl alternate immersion per ASTM G44. 

Alloy Temper Rating Rationale for Rating

2195 T8 

(Various 

conditions) 

Table II 5 out of 7 ST specimens failed at 75% YS within 30 days of 

exposure (11, 12, 18, 27, and 30 days) to 3.5% NaCl alternate 

immersion. None out of 4 ST specimens failed at 50% YS 

within 30 days of exposure. 

2219 T87 Table I None out of 5 ST specimens failed at 75% YS within 30 days 

of exposure to 3.5% NaCl alternate immersion.

Table I = A rating = Highly resistant to SCC in a sodium chloride environment 

Table II = B rating = Moderately resistant to SCC in a sodium chloride environment 

Table III = C rating = Low resistance to SCC in a sodium chloride environment 

11.0 Supplemental Mechanical Test Program 

During the execution of the mechanical property testing and analysis of the aft bulkhead, several 

issues arose which the NESC team attempted to address to assist the Orion designers team in 

their first article test program. In addition, several findings were observed that the team wished 

to further analyze to clarify the results. The NESC team proposed a limited number of 

supplemental tensile, fracture, and SCC tests, which were accepted by the NESC advisory team. 

Further details on these supplemental tests are addressed in Sections 11.1 through 11.3. Due to 

project milestones and schedule, the results from these supplemental tests will not be included in 

this final report, but will be published as an addendum at a later date. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

171 of 223

NESC Request No.: TI-13-00884 

11.1 Tensile 

Based on the results of the tensile tests performed on the aft bulkhead and the limited amount of 

handbook data available for interpretation of the results, a limited quantity of additional tensile 

tests will be conducted to address key questions. Table 11.1-1 shows the supplemental tensile 

test matrix and lists questions being addressed. 

Table 11.1-1. Supplemental Tensile Test Matrix 

Material 

Source

Location / Heat 

Treatment

Orient.

Throughthickness 

position

# of Specimens Question Addressed

t/8 3

7t/8 3

t/8 3

7t/8 3

L t/2 3

LT t/2 3

ST t/2 3

L t/2 3

LT t/2 3

ST t/2 3

1. What are the tensile properties at other 

through-thickness locations in the aft 

bulkhead?

2. What effect does the inhomogeneous 

microstructure have on the tensile 

properties of the aft bulkhead?

3. How do the tensile properties of thh aft 

bulkhead compare to wrought plate?

4. What effect does a slower quench during 

heat treat processing have on the tensile 

properties of the material?

 

5. Are the high ST tensile properties in the aft 

bulkhead inherent to the plate lot or are they 

an artifact of spin form processing?

Typical Plate

SHT + water 

quench + age, 

375°F/36h

L

LT

Aft Bulkhead L2

Modified Plate

SHT + 

water/glycol 

quench + age, 

375°F/36h

Based on microstructural characterization of the aft bulkhead, the post-recrystallization grain 

morphology varies with meridian distance and through-thickness position, with larger grain sizes 

associated with likely regions of higher deformation. These grain size differences are biased 

toward the OML, which is in direct contact with the forming tool. To characterize these effects 

on the tensile properties, tensile specimens from coupon blank L2 (arc length = 36.0 in; meridian 

angle 347°) will be tested at both the t/8 (near the IML surface) and 7/t8 (near the OML surface) 

through-thickness locations for comparison to tensile test results previously acquired at the t/2 

location only. These through-thickness positions showed the most variation in grain size. In 

addition, the membrane region of the finished machined aft bulkhead will likely be located near 

the OML surface so tensile properties from this region will be of interest to the Orion designers. 

Additional testing was designed to address the heat treat practice used in the processing of the aft 

bulkhead as described in Section 7.8. The solution heat treat and quench operation used by 

Spincraft consisted of a quench in a water/glycol mixture which results in a slower overall 

cooling rate to reduce part distortion and residual stress in the final product. Although this 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

172 of 223

NESC Request No.: TI-13-00884 

quench operation is permissible per AMS 2770, the slower cooling rate affects the precipitation 

kinetics during subsequent aging and may impact material properties (40). 

Remnant –F temper plate machining drops from the aft bulkhead forming blank were heat treated 

to the –T62 temper as per AMS 2770. Two heat treat conditions were evaluated: typical plate 

which was quenched in water following solution heat treatment (SHT) and modified plate which 

was quenched in a water/glycol mixture similar to that used by Spincraft. Tensile tests will be 

conducted on both heat treated plates to determine if the slower quench rate has any impact on 

the tensile properties. 

The tensile tests of the aft bulkhead revealed that the ST tensile properties were substantially 

higher than the L and LT orientations (by ~ 4-6 ksi) depending on the aft bulkhead location. The 

NESC team was not able to find any comparable data for wrought plate or other product forms in 

the –T62 temper for the ST orientation. A search of the literature for other 2xxx series Al alloys 

did show that the ST tensile properties are typically lower than the L and LT orientations. 

Additional tensile tests will be conducted in the ST orientation for both heat treated plate 

conditions and compared to the aft bulkhead tensile test results to determine if the high ST 

tensile properties are a result of the spin forming processing or are they inherent to the starting 

material condition and subsequent processing. The ST YS is additionally of interest because this 

data was used to define the exposure stress levels for the SCC testing and may have resulted in 

the specimens being exposed at a higher stress level than comparable handbook data. 

11.2 Fracture Toughness 

Due to the lack of available fracture data in the literature, and in response to the questions 

regarding plate processing, supplemental fracture toughness tests shown in Table 11.2-1 will be 

performed on the typical and modified plates. Specific questions being addressed by this 

supplemental fracture toughness testing include whether the spin form processing compromises 

the fracture toughness of the material and whether the slower quench used during heat treatment 

of the aft bulkhead has any effect on the fracture toughness compared to the normal water 

quench rate. 

Table 11.2-1. Supplemental Fracture Toughness Test Matrix 

Material 

Source

Location/Heat 

Treatment

Orient.

Throughthickness 

position

# of Specimens Question Addressed

L-T t/2 2

T-L t/2 2

S-T t/2 2

L-T t/2 2

T-L t/2 2

S-T t/2 2

1. How does the fracture toughness 

properties of the aft bulkhead compare to 

wrought plate?

2. What is the impact of a slower quench 

rate during heat treat processing have on the 

fracture toughness of the material?

Modified Plate

SHT + 

water/glycol 

quench + age, 

375°F/36h

Typical Plate

SHT + water 

quench + age, 

375°F/36h
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

173 of 223

NESC Request No.: TI-13-00884 

11.3 Stress Corrosion 

When evaluating the SCC test results and making comparisons with handbook or published data 

in an attempt to interpret the SCC results, several questions and issues arose. The primary 

question was whether the failure that occurred in the ST orientation at the exposure stress of 50% 

YS for coupon blank M10 was an outlier? 

A complication that impeded interpreting the results is that there is very little SCC data available 

for Al 2219-T6 products. In addition, several questions arose regarding the available data for Al 

2219-T8 products, both in terms of SCC test practices and the available data to substantiate 

published ratings. Specifically, what the appropriate basis for the applied stress level should be. 

There are a number of applicable standards for SCC testing that use different applied stress 

levels, exposure periods, and criterion ratings. Most are based on MMPDS allowable YS, but 

the MSFC SCC test standard, MSFC-STD-3029, Revision A, uses typical YS for the product 

being tested. The ST YS of the aft bulkhead is higher than typical values which may have 

resulted in a more severe test than the handbook data being used for comparison. 

All of the SCC testing procedures used in the evaluation of the aft bulkhead and SCC resistance 

table ratings were based on MSFC-STD-3029, Revision A, which is more conservative than 

ratings listed in ASTM G64 (33). The applied stress levels for these tests were based on the 

actual material properties, whereas the handbook data is based on the MMPDS design allowable 

material properties, which are typically lower than actuals or typicals due to the statistical 

analysis. Since the susceptibility of metallic materials to stress corrosion tends to increase with 

the applied stress, the higher reported ST properties in the aft bulkhead result in a more 

aggressive test conditions compared to the reference data in the literature. To address this issue, 

additional SCC tests will be conducted on coupon blank M10 using applied stress levels based 

on MMPDS A-basis design allowables for Al 2219-T62 plate. 

Additional general questions arose regarding how the SCC ratings in published literature were 

established. What type of SCC data will Orion use to base their design? What is the threshold 

stress level for SCC for the aft bulkhead? Due to limited funds and schedule, not all of these 

questions can be addressed in the scope of this supplemental SCC test program. 

Table 11.3-1 lists the SCC test matrix, test priorities, and the questions being addressed. These 

supplemental SCC tests will consist of 30-day alternate immersion in a 3.5% NaCl environment 

and will only evaluate the ST orientation since this is the most susceptible grain orientation to 

SCC and the orientation of the failures in question. The goal of the supplemental SCC test 

matrix is to ensure confidence in the data that has been generated, and characterize the aft 

bulkhead component as best as possible. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

174 of 223

NESC Request No.: TI-13-00884 

Table 11.3-1. Supplemental SCC Test Matrix Material 

Source

Location/Heat 

Treatment Applied Stress Level, % YS

Applied 

Stress Level, 

ksi

Orient. # of 

Specimens

# of Specimens 

per Group Question Addressed Priority

50 based on M10 avg. ST YS 22.2 ST 3

75 based on M10 avg. ST YS 33.3 ST 3

50 based on MMPDS LT YS 18.0 ST 3

75 based on MMPDS LT YS 27.0 ST 3

0 0.0 ST 3

50 based on MMPDS LT YS 18.0 ST 3

75 based on MMPDS LT YS 27.0 ST 3

0 0.0 ST 3

50 based on MMPDS LT YS 18.0 ST 3

75 based on MMPDS LT YS 27.0 ST 3

0 0.0 ST 3

50 based on MMPDS LT YS 18.0 ST 3

75 based on MMPDS LT YS 27.0 ST 3

0 0.0 ST 3

50 based on MMPDS LT YS 18.0 ST 3

75 based on MMPDS LT YS 27.0 ST 3

0 0.0 ST 3

50 based on MMPDS LT YS 18.0 ST 3

75 based on MMPDS LT YS 27.0 ST 3

0 0.0 ST 3

50 based on MMPDS LT YS 18.0 ST 3

75 based on MMPDS LT YS 27.0 ST 3

Aft 

Bulkhead M10 6

Is failure at 50% exposure stress repeatable? 

Was this data point an outlier or it is 

representative of this aft bulkhead location?

Aft 

Bulkhead M10 6

Does material pass at exposure stress levels 

based on MMPDS design properties rather 

than actual material yield strength?

2 Aft 

Bulkhead J2 9

Aft 

Bulkhead J3 9

1

SHT + 

water/glycol 

quench + age, 

375F/36h

SHT + water 

quench + age, 

375F/36h

What is the SCC behavior in other coupon 

blank locations along a different meridian 

line?

Note: These specimens have already been 

machined and installed in stressing frames. 

CPST Spin 

Formed 

Dome

T62 9 How does the aft bulkhead compare with 

other spin formed domes?

Modified 

Plate 9 Does the quench rate affect SCC resistance of plate?

Aft 

Bulkhead J1 9

3

Typical 

Plate 9 Does spin forming alter the SCC resistance of plate? 

The first priority of these supplemental SCC tests was to repeat the tests on coupon blank M10 to 

determine whether the one failure in the ST orientation that occurred at 50% YS applied stress 

level was an anomaly. The concern was the viability of the limited data set and its potential 

impact on the SCC rating. Typically, a larger number of replicate tests are conducted to establish 

a statistical basis for SCC resistance due to inherent variability in corrosion and stress corrosion 

testing. The first priority tests will repeat the tests for material from coupon blank M10 with the 

applied stress levels based on the actual test data for the coupon blank to see if the results are 

repeatable. Additional tests from the same coupon blank will be conducted at applied stress 

levels based on MMPDS design values to determine whether or not the material would pass 

exposure at lower stress levels. 

The second priority tests are in response to input from the LM Orion Program to better 

understand the SCC resistance throughout the aft bulkhead. The SCC specimens from coupon 

blank J1, J2, and J3 designated for seacoast exposure SCC testing were re-directed to alternate 

immersion SCC testing in order to examine more locations in the aft bulkhead. Seacoast 

exposure SCC testing was proposed in the original test program because of concerns based on 

testing in the past where the alternate immersion test results become obscured because of general 

corrosion in the form of pitting and concerns on whether the SCC test results were valid. 

Seacoast exposure SCC testing, which is performed in a natural outdoor environment and 

requires longer test durations than the standard accelerated corrosion tests performed in a 

laboratory, is used as a complementary test to alternate immersion. Based on the preliminary 

alternate immersion SCC test results, the NESC team decided that there was no longer a need to 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

175 of 223

NESC Request No.: TI-13-00884 

conduct the seacoast exposure SCC testing. These seacoast exposure SCC specimens had 

already been machined and loaded in the stressing frames; the only change required was to 

change the applied stress levels and install them in the alternate immersion test apparatus. For 

these tests, the applied stress level will be based upon MMPDS A-basis design properties. These 

specimens offered a ready opportunity to generate the additional data while staying within the 

prescribed budget and schedule. 

The third priority tests are in response to the lack of available SCC data for Al 2219-T6 products. 

The tests also address whether the lower SCC resistance of the aft bulkhead is inherent in this 

plate lot or due to the spin forming process. Tests will be performed on plate processed to the 

T62 temper using the typical and modified heat treat procedures to evaluate the effect of spin 

forming. Remnant spin formed Al 2219-T62 dome material from the CPST Program (21) will 

provide data for a comparable product form. For these tests, the applied stress level will be 

based upon MMPDS A-basis design properties. 

12.0 Findings, Observations, and NESC Recommendations 

The following findings, observations, and recommendations are based on the results of a study 

for which the main objective was to determine whether there are technical obstacles relative to 

the spin forming a single piece APVHB. 

The Phase II M&P studies did not identify any potential insurmountable technical issues that 

would preclude spin forming the APVBH. The potential benefits of spin forming an Al 2219 

APVBH include reduced weight and production costs, which are associated with eliminating 

welds and weld lands, and improved performance and design margins. 

12.1 Findings 

The following findings were identified: 

F-1. The aft bulkhead microstructure varies both through-thickness and along the meridian arc 

length positions, with larger grain sizes associated with likely regions of higher 

deformation. 

x Grain size was larger toward the rim and toward the OML surface, likely 

associated with the combined stresses necessary to shape the material to fit the 

mandrel. 

x These variations in grain size are indicative of the complex and varied 

deformation levels associated with the spin forming process, particularly when 

combined with the plate rolling history and post-forming heat treatment. 

F-2. Tensile tests designed to determine tensile property uniformity over the aft bulkhead 

acreage noted that the tensile properties varied with location in the aft bulkhead. 

x For the L and LT orientations, a trend of increasing tensile and YS with arc length 

distance from the pole was evident. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

176 of 223

NESC Request No.: TI-13-00884 

x Conversely, the properties were uniform in the circumferential direction. 

x The ST tensile properties were notably greater than those for the other 

orientations (L, LT, ST45), but elongations were about half. 

F-3. The tensile properties of the spin formed Al 2219-T62 aft bulkhead material were typical 

for established 2219-T62 products. 

x Tensile properties were comparable to the MMPDS design properties for T62 

wrought plate and other fabricated products in the T6 temper, such as spin formed 

domes, forgings and rolled rings. 

x Tensile properties were lower than those for Al 2219-T851 and T87 plate, as 

expected due to the increased precipitation strengthening in T8 temper wrought 

products that is imparted by the cold stretch/work prior to artificial aging. 

x The lower tensile strength of the spin formed Al 2219-T62 aft bulkhead material 

compared with Al 2219-T851 and T87 plate is due to differences in material 

temper and not the spin forming process. 

F-4. Fracture toughness was uniform with location in the aft bulkhead and indicated excellent 

damage tolerance capability. 

x In-plane (T-L and L-T) toughness values are relatively constant for a given 

orientation and do not vary significantly across the aft bulkhead acreage. 

x Through-thickness (S-T) toughness appears uniform as well, but exhibits 

significant data scatter for a given bulkhead location. 

x Spin formed 2219-T62 aft bulkhead material exhibited rising R-curve for all 

orientations and locations and toughness-to-YS ratios in excess of 60%. 

x High toughness values, high toughness-to-YS ratios, and rising R-curve behavior 

suggest excellent damage tolerance capability for the spin formed Al 2219-T62 

aft bulkhead material. 

F-5. The fracture toughness of the spin formed Al 2219-T62 aft bulkhead material was typical 

for established 2219-T62 products. 

x Fracture toughness values exhibited the typical variation with orientation: L-T 

orientation > T-L orientation > S-T orientation. 

x Fracture toughness was in-family with conventional Al 2219 Al tempers and 

product forms. Toughness values were comparable to Al 2219-T62 and T851 

plate and are greater than for T87 plate, which is consistent with the tensile 

strength being lower than for T87 plate. 

F-6. The SCC resistance of the spin formed 2219-T6 material varied with location in the aft 

bulkhead and in some locations exhibited lower resistance than previously established for 

2219-T6 material. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

177 of 223

NESC Request No.: TI-13-00884 

x Regions near the pole exhibited moderate resistance to SCC (Table II per MSFC3029), near the rim a high resistance to SCC (Table I), and one of the areas in the 

membrane a low resistance to SCC (Table III). 

x The LT orientation appeared to be significantly more resistant to SCC than the ST 

orientation. Residual strength after exposure was significantly higher for LT 

specimens than ST specimens.

x The 90-day alternate immersion exposure appears to be too long for the spin 

formed 2219-T62 material since failures can occur by corrosion mechanisms 

(general and pitting corrosion) different than those for SCC, which can interfere 

with the SCC evaluation.

12.2 Observations 

The following observations were identified: 

O-1. The rationale for the variations in tensile properties with location in the aft bulkhead was 

not fully characterized. The microstructure at the through-thickness location tested (t/2) 

was more uniform throughout the aft bulkhead than at other locations. 

O-2. Limited data was available in handbooks or open literature publications for Al 2219-T6 

material for comparison with the aft bulkhead properties, consequently it was difficult to 

assess the aft bulkhead in the context of other commercial Al 2219-T6 products. 

x Tensile data were unavailable in handbooks or open literature publications for the 

ST and ST45 orientations, consequently these properties could only be assessed in 

comparison with established values for the L and LT orientations. 

x Fracture toughness data was only available in handbooks and open literature 

publications for Al 2219-T6 and -T8 plate. No fracture toughness data was 

publicly available for 2219 spin formed products. 

x The SCC data for the aft bulkhead provides insight about the SCC resistance of 

the spin formed 2219-T62 material, but is insufficient to establish a threshold 

level. 

O-3. Fracture toughness data suggests excellent damage tolerance in the 2219-T6 spin formed 

material; however, surface crack tension and da/dN testing is necessary to more fully 

characterize damage tolerance. 

O-4. Questions arose regarding SCC test procedures, particularly the basis for exposure stress 

levels and test durations, which may impact direct comparison of the aft bulkhead SCC 

results with the very limited handbook and open literature data. 

O-5. The SCC tests performed provided an initial indication of the SCC susceptibility of the 

spin formed 2219-T62 material; however, environmentally assisted fracture toughness 

(KEAC) and fatigue (da/dN)SCC)) in the S-T orientation in a 3.5% NaCl environment is 

required to understand the impact of the SCC susceptibility on fracture and fatigue. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

178 of 223

NESC Request No.: TI-13-00884 

O-6. The laboratory 30-day alternate immersion accelerated test condition provides adequate 

screening methodology for SCC; however, longer test durations of 90 days did lead to 

severe general corrosion and pitting. For determining actual serviceability of the 

material, other stress corrosion tests should be performed in the intended service 

environment. 

12.3 NESC Recommendations 

The following NESC recommendations were identified and directed towards the MPCV Program 

and the NESC: 

R-1. The microstructural variability of the Orion first article spin formed aft bulkhead should 

be determined and mechanical property testing designed to sample regions of maximum 

and minimum grain size in order to evaluate the effect of variable microstructures, if 

observed. (F-1, F-2, O-1) 

R-2. Additional testing should be performed on first article and initial serial production aft 

bulkhead components to generate data to populate the material property database for Al 

2219-T6 spin formed products. (O-2) 

x Tensile testing should be continued until sufficient data is generated to 

demonstrate consistency in material properties and build confidence that the spin 

forming process is reproducible. 

x Fracture testing should generate data to more substantially populate the KJIc

fracture toughness database. 

x Stress corrosion cracking testing should be continued until sufficient data is 

generated to establish the SCC threshold stress level. 

R-3. Perform surface crack tension fracture toughness and fatigue crack growth rate (da/dN) 

testing in order to fully characterize damage tolerance. (O-3)

R-4. Exercise caution in using published handbook and table ratings for the SCC resistance of 

Al 2219-T6. Handbook and open literature publications should be reviewed in order to 

substantiate that the SCC test procedures and data generated are directly comparable to 

the MSFC-STD-3029 standard used in the SCC evaluation of the Al 2219-T62 aft 

bulkhead (O-4) 

R-5. Perform environmentally assisted fracture toughness (KEAC) and fatigue ((da/dN)SCC) 

tests in the S-T orientation in a 3.5% NaCl environment in order to understand the impact 

of the SCC susceptibility of the material on fracture toughness and fatigue. (O-5) 

R-6. Perform seacoast exposure SCC testing to characterize the corrosion performance of the 

aft bulkhead in the natural service environment. (O-6) 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

179 of 223

NESC Request No.: TI-13-00884 

13.0 Alternate Viewpoint 

There were no alternate viewpoints identified during the course of this assessment by the NESC 

team or the NRB quorum. 

14.0 Other Deliverables 

No unique hardware, software, or data packages, outside those contained in this report, were 

disseminated to other parties outside this assessment. 

15.0 Lessons Learned 

No applicable lessons learned were identified for entry into the NASA Lessons Learned 

Information System (LLIS) as a result of this assessment. 

16.0 Recommendations for NASA Standards and Specifications 

No recommendations for NASA standards and specifications were identified as a result of this 

assessment. 

17.0 Definition of Terms 

Corrective Actions Changes to design processes, work instructions, workmanship practices, 

training, inspections, tests, procedures, specifications, drawings, tools, 

equipment, facilities, resources, or material that result in preventing, 

minimizing, or limiting the potential for recurrence of a problem. 

Finding A relevant factual conclusion and/or issue that is within the assessment 

scope and that the team has rigorously based on data from their 

independent analyses, tests, inspections, and/or reviews of technical 

documentation. 

Lessons Learned Knowledge, understanding, or conclusive insight gained by experience 

that may benefit other current or future NASA programs and projects. 

The experience may be positive, as in a successful test or mission, or 

negative, as in a mishap or failure. 

Observation A noteworthy fact, issue, and/or risk, which may not be directly within the 

assessment scope, but could generate a separate issue or concern if not 

addressed. Alternatively, an observation can be a positive 

acknowledgement of a Center/Program/Project/Organization’s operational 

structure, tools, and/or support provided. 

Problem The subject of the independent technical assessment. 

Proximate Cause The event(s) that occurred, including any condition(s) that existed 

immediately before the undesired outcome, directly resulted in its 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

180 of 223

NESC Request No.: TI-13-00884 

occurrence and, if eliminated or modified, would have prevented the 

undesired outcome. 

Recommendation A proposed measurable stakeholder action directly supported by specific 

Finding(s) and/or Observation(s) that will correct or mitigate an identified 

issue or risk. 

Root Cause One of multiple factors (events, conditions, or organizational factors) that 

contributed to or created the proximate cause and subsequent undesired 

outcome and, if eliminated or modified, would have prevented the 

undesired outcome. Typically, multiple root causes contribute to an 

undesired outcome. 

Supporting Narrative A paragraph, or section, in an NESC final report that provides the detailed 

explanation of a succinctly worded finding or observation. For example, 

the logical deduction that led to a finding or observation; descriptions of 

assumptions, exceptions, clarifications, and boundary conditions. Avoid 

squeezing all of this information into a finding or observation 

18.0 Acronyms List 

AM Additive Manufacturing 

AMA Analytical Mechanics Associates 

AMS Aerospace Material Specifications 

APVBH Aft Pressure Vessel Bulkhead 

ASTM American Society for Testing and Materials 

BH Bulkhead 

C(T) Compact Tension 

CL Centerline 

CM Crew Module 

CPST Cryogenic Propellant Storage and Transfer 

COD Crack-Mouth Opening Displacement 

E Modulus 

EBSD Electron Backscatter Diffraction 

ESCG Engineering and Science Contract Group 

FPPW Friction Pull Plug Welding 

FPVBH Forward Pressure Vessel Bulkhead 

FSW Friction Stir Weld 

FSWSFD Friction Stir Welded Spin Formed Dome 

FTU Design Ultimate Tensile Strength, Tension 

FTY Design Yield Strength, Tension 

IML Inner Mold Line 

in Inch 

ipm Inches Per Minute 

JIC J integral 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

181 of 223

NESC Request No.: TI-13-00884 

JSC Johnson Space Center 

K Crack Tip Stress Intensity, ksi√in

KIC Critical Crack Tip Stress Intensity 

KIC Plane Strain Fracture Toughness 

kips 1,000 pounds 

KJIC Plane Strain Fracture Toughness 

KSC Kennedy Space Center 

ksi Kilopound per square inch, 103

L Length 

L Longitudinal (direction parallel to plate rolling direction) 

LALab Light Alloy Laboratory 

LaRC Langley Research Center 

LM Lockheed Martin 

LT Long Transverse (direction perpendicular to rolling direction) 

M&P Materials and Processes 

MAF Michoud Assembly Facility 

MUA Materials Usage Agreement 

MMPDS Metallic Material Properties Development and Standardization 

MPCV Multi-Purpose Crew Vehicle 

MSFC Marshall Space Flight Center 

Msi Megapound per square inch, 106

NaCl Sodium Chloride 

NASA National Aeronautics and Space Administration 

NESC NASA Engineering and Safety Center 

NRB NESC Review Board 

OML Outer Mold Line 

psi Pounds Per Square Inch 

R-curve Resistance Curve 

S/N Serial Number 

SCC Stress Corrosion Cracking 

SHT Solution Heat Treatment 

SiC Silicon Carbide 

SLS Space Launch System 

SR-FSW Self-Reacting Friction Stir Weld 

SSC Stennis Space Center 

ST Short Transverse (direction perpendicular to rolling direction) 

ST45 45 Degree Through-Thickness (direction perpendicular to rolling direction) 

t Thickness 

WCM Welded Crew Module 

YS Yield Strength 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

182 of 223

NESC Request No.: TI-13-00884 

19.0 References 

1. M. S. Domack, E. K. Hoffman. I. S. Raju, R. S. Piascik. Spin Forming Aluminum Alloy Crew 

Module (CM) Metallic Forward Pressure Vessel Bulkhead (FPVBH) – Phase I. February 

2014. NASA/TM-2014-218163; NESC-RP-12-00776. 

2. Runge, Manfred. Spinning and Flow Forming. [trans.] David H. Pollitt. s.l. : verlag modern 

industrie AG, 1993. Original title: Drücken and Drückwalzen. 

3. AMS-QQ-A-250/30. Aerospace Material Specification: Aluminum Alloy 2219, Plate and 

Sheet. Warrendale, PA: SAE International, 2010. AMS-QQ-A-250/30. 

4. Cullen, R. M. Spin Formed Aluminum 2219 Aft Bulkhead Pathfinder Component. North 

Billerica, MA : Spincraft Engineering Technologies Group, January 15, 2014. Contract 

NNL13AF652P. 

5. AMS 2770H. Aerospace Materials Specification: Heat Treatment of Wrought Aluminum Alloy 

Parts. Warrendale, PA : SAE International, 2006. AMS 2770H. 

6. AMS 2658. Aerospace Material Specificatin: Hardness and Conductivity Inspection of 

Wrought Aluminum Alloy Parts. Warrendale, PA : SAE International, 2003. AMS 2658. 

7. ASTM E8 - Standard Test Methods for Tension Testing of Metallic Materials. West 

Conshohocken, PA : ASTM International, 2011. E8. 

8. ASTM E1820 - Standard Test Method for Measurement of Fracture Toughness. West 

Conshohocken, PA : American Society for Testing and Materials, 2013. E1820. 

9. ASTM G49 - Standard Practice for Preparation and Use of Direct Tension Stress-Corrosion 

Test Specimens. West Conshohocken, PA : ASTM International, 2011. G49. 

10. ASTM G44 -Standard Practice for Exposure of Metals and Alloys by Alternate Immersion in 

Neutral 3.5 % Sodium Chloride Solution. West Conshohocken, PA : ASTM International, 

2013. G44. 

11. ASTM B117: Standard Practice for Operating Salt Spray (Fog) Apparatus1. West 

Conshohocken, PA : ASTM International, 2011. 

12. MSFC-STD-3029, Rev. A: Guidelines for the Selection of Metallic Materials for Stress 

Corrosion Cracking Resistance in Sodium Chloride Environments. Huntsville, AL : 

NASA MSFC, 2005. MSFC-3029A. 

13. ASTM G47 - Standard Test Method for Determining Susceptibility to Stress-Corrosion 

Cracking of 2XXX and 7XXX Aluminum Alloy Products. West Conshohocken, PA : ASTM 

International, 2011. G47. 

14. F. J. Humphreys, M. Hatherly. Recrystallization and Related Annealing Phenomena, 2nd 

Edition. New York, NY : Elsevier Ltd., 2004. pp. p. 314-325. 

15. J. E. Hatch, ed. Aluminum - Properties and Physical Metallurgy. Metals Park, OH : 

American Society for Metals, 1984. pp. p. 134-199. 

16. Atlas of Microstructures of Industrial Alloys, Metals Handbook. Metals Park, OH : American 

Society for Metals, 1972. p. 284. 

17. Metallic Materials Properties Development and Standardization (MMPDS) Handbook. 

Columbus, OH : Battelle Memorial Institute, April 2013. MMPDS-08. 

18. Aluminum Standards and Data 2013. s.l. : The Aluminum Association, Inc., November 2013. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

183 of 223

NESC Request No.: TI-13-00884 

19. Cullen, R.M. Single Piece Orion Forward Bulkhead Demonstrator, Summary Report. North 

Billerica, MA : Spincraft, April 2012. ITAR Restricted - Export Control; Lockheed Martin 

Purchase Order 4100270793. 

20. Orion Bulkhead Test Data. s.l. : Westmoreland Mechanical Test Laboratory, June 14, 2012. 

Addendum to Single Piece Orion Forward Bulkhead Demonstrator, Summary Report. 

21. McGill, P., Talton, M. Materials and Processes Laboratory Flash Report, MPFR-14-019: 

CPST Spun Dome Material Characterization, July, 2014. Huntsville, AL : NASA Marshall 

Space Flight Center, July 2014. MPFR-14-09. 

22. Cullen, R. M. Senior Manufacturing Engineer, Spincraft. North Billerica, MA : s.n., 

May 18, 2014. Private communication. 

23. Aluminum Alloy Forgings and Rolled or Forged Rings 6.3Cu - 0.30Mn - 0.18Zr - 0.10V - 

0.06Ti (2219-T6). Aerospace Material Specification. Warrendale, PA : SAE International, 

July 2012. AMS 4143E. 

24. Anderson, T. L. Fracture Mechanics, 3rd Edition. s.l. : CRC Press, Taylor and Francis 

Group, 2005. 

25. McGill, P. 2219 Aluminum Fracture Characterization as a Function of Temper. Huntsville, 

AL: NASA Marshall Space Flight Center, August, 2014. Materials and Processes 

Laboratory Flash Report. MPFR-14-024. 

26. Fatigue and Fracture, ASM Handbook. Metals Park, OH : ASM International, 1996. p. 776. 

Vol. 19. 

27. ASTM E647 - Standard Test Method for Measurement of Fatigue Crack Growth Rates. West 

Conshohocken, PA : ASTM International, 2013. E647. 

28. ASTM E2899 - Standard Test Method for Measurement of Initiation Toughness in Surface 

Cracks Under Tension and Bending. West Conshohocken, PA : ASTM International, 2013. 

E2899. 

29. NASA-STD-5019, Fracture Control Requirements for Spaceflight Hardware. Washington, 

DC : National Aeronautics and Space Administration, January 2008. NASA-STD-5019. 

30. API 579-1/ASME FFS-1 - Fitness-For-Service. Washington, DC : American Petroleum 

Institute/American Society of Mechanical Engineers, June 5, 2007. API 579 2nd edition; 

February 2009 Errata. 579. 

31. Mayer, L. W. Alcoa Green Letter 176 - Alcoa Aluminum Alloy 2219. New Kensington, PA : 

Aluminum Company of America, Applications Engineering Division, June 1957. 176. 

32. Spuhler, E. H. and Brown, C. L. Alcoa Green Letter 188 - Avoiding Stress-Corrosion 

Cracking in High Strength Aluminum Alloy Structures. New Kensington, PA : Aluminum 

Company of America, August 1, 1962. 

33. ASTM G64 - Standard Classification of Resistance to Stress-Corrosion Cracking of HeatTreatable Aluminum Alloys. West Conshohocken, PA : ASTM International, 2013. G64. 

34. Sprowls, D. O., Lifka, B. W., Vandenburgh, D. G., R.L. Horst, R. L., Shumaker, M. B.,. 

NASA-CR-88110. Investigation of the Stress-Corrosion Cracking of High-Strength 

Aluminum Alloys. New Kensington, PA : Aluminum Company of America, Alcoa Research 

Laboratories, Final Report for the period May 6, 1963 – October 6, 1966. Contract Number 

NAS 8-5340. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

184 of 223

NESC Request No.: TI-13-00884 

35. Stewart, T. J. SCC Test Methods Regarding Aluminum Alloy 2219. Letter from T.J. Stewart 

to F. Oaks. Memo 3-4820-194. Meeting at Alcoa Research Laboratories, New Kensington, 

PA : s.n., June 20, 1963. 

36. Sprowls, D. O., Lifka, B. W., King, W., Shumaker, M. B. Investigation of the StressCorrosion Cracking of High-Strength Aluminum Alloys. New Kensington, PA. : Aluminum 

Company of America, Fifth Quarterly Report May 1 – July 31, 1964. NASA-CR-155461. 

37. Speidel, M. O. A Chapter Prepared for ARPA Handbook Stress Corrosion Cracking of 

Aluminum Alloys. Ohio State University. 1976. 1976-00-00. Advanced Research Projects 

Agency (ARPA). 

38. MSFC Memorandum EH24 (94-107); Stress Corrosion Cracking Evaluation of Aluminum 

Lithium Alloy 2195. Huntsville, AL: NASA, October 31, 1994. 

39. NASA MSFC Memorandum EH24 (95-97) Stress Corrosion Evaluation of Aluminum Alloy 

2219-T87, 10.2-cm (4-in) Thick Plate. Huntsville, AL: s.n., October 1995. 

40. Influence of quench and heating rates on the ageing response of an Al–Zn–Mg–(Zr) alloy. A. 

Deschamps, Y. Bre ́chet. 1998, Materials Science and Engineering, Vol. A251, 

pp. 200-207. 

41. American National Standard Alloy and Temper Designation Systems for Aluminum. 

Arlington, VA: The Aluminum Association, Inc., 2013. ANSI H35.1/H35. 

 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

185 of 223

NESC Request No.: TI-13-00884 

20.0 Appendix 

20.1 Appendix A: Temper Designations (41) 

F As fabricated (no mechanical property limits specified). 

O Annealed - products achieving the required annealed properties after hot forming 

processes may be designated as O temper. 

T4 Solution heat treated and naturally aged to a substantially stable condition. 

T6 Solution heat treated and then artificially aged by the material producer. 

T62 Solution heat treated and then artificially aged. Applies to test material heat 

treated from annealed or F temper or to products heat treated from any temper by 

the user. 

T8 Solution heat treated, cold worked and then artificially aged. 

T851 Solution heat treated, stress relieved by controlled stretching (permanent set 1.5% 

to 3% for plate, 1% to 5% for hand or ring forging and rolled ring) and then 

artificially aged. 

T87 Solution heat treated, cold worked by a thickness reduction of approximately 7% 

and then artificially aged. 

20.2 Appendix B: Material Certification 

A material certification report was provided by Alcoa for the plate used in fabrication of the 

pathfinder aft bulkhead and is shown in Figure 20.2-1. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

186 of 223

NESC Request No.: TI-13-00884 

Figure 20.2-1. Material certification report for the 2219-F plate. 

 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

187 of 223

NESC Request No.: TI-13-00884 

20.3 Appendix C: Fracture Toughness Data 

A complete data report for each fracture toughness specimen is provided. 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

188 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

189 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

190 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

191 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

192 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

193 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

194 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

195 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

196 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

197 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

198 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

199 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

200 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

201 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

202 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

203 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

204 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

205 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

206 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

207 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

208 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

209 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

210 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

211 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

212 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

213 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

214 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

215 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

216 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

217 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

218 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

219 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

220 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

221 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

222 of 223

NESC Request No.: TI-13-00884 
NASA Engineering and Safety Center 

Technical Assessment Report

Document #: 

NESC-RP13-00884

Version: 

1.0 

Title:

Spin Forming Al CM Metallic APVBH – Phase II 

Page #: 

223 of 223

NESC Request No.: TI-13-00884 
REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188

2. REPORT TYPE 

Technical Publication

 4. TITLE AND SUBTITLE

Spin Forming Aluminum Crew Module (CM) Metallic Aft Pressure Vessel 

Bulkhead (APVBH) - Phase II

5a. CONTRACT NUMBER

 6. AUTHOR(S)

Hoffman, Eric K.; Domack, Marcia S.; Torres, Pablo D.; 

McGill, Preston B.; Tayon, Wesley A.; Bennett, Jay E.; 

Murphy, Joseph T.

 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

NASA Langley Research Center

Hampton, VA 23681-2199

 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

 8. PERFORMING ORGANIZATION

 REPORT NUMBER

L-20517 NESC-RP-13-00884

10. SPONSOR/MONITOR'S ACRONYM(S)

NASA

13. SUPPLEMENTARY NOTES

12. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified - Unlimited

Subject Category 16 Space Transportation and Safety

Availability: NASA CASI (443) 757-5802

19a. NAME OF RESPONSIBLE PERSON

STI Help Desk (email: help@sti.nasa.gov)

14. ABSTRACT

The principal focus of this project was to assist the Multi-Purpose Crew Vehicle (MPCV) program in developing a spin 

forming fabrication process for manufacture of the Orion crew module (CM) aft pressure vessel bulkhead. The spin forming 

process would result in a single piece aluminum (Al) alloy 2219 aft bulkhead resulting in the elimination of the current 

multiple piece welded construction, simplify CM fabrication, and lead to an enhanced design. This report will focus on the aft 

bulkhead portion of this study only. Phase I (NASA TM-2014-218163, (1)) of this assessment explored spin forming the 

single-piece CM forward pressure vessel bulkhead.

15. SUBJECT TERMS

Spin Forming; Crew Module; Aft Pressure Vessel Bulkhead; NASA Engineering and Safety Center; Multi-Purpose Crew 

Vehicle

18. NUMBER

 OF 

 PAGES

228

19b. TELEPHONE NUMBER (Include area code)

(443) 757-5802

a. REPORT

U

c. THIS PAGE

U

b. ABSTRACT

U

17. LIMITATION OF 

 ABSTRACT

UU

Prescribed by ANSI Std. Z39.18

Standard Form 298 (Rev. 8-98)

3. DATES COVERED (From - To)

July 2013 - November 2014

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

869021.05.07.09.43

11. SPONSOR/MONITOR'S REPORT

 NUMBER(S)

NASA/TP-2015-218674

16. SECURITY CLASSIFICATION OF:

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, 

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and 

Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person 

shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.

1. REPORT DATE (DD-MM-YYYY)

01- 01 - 2015