**Process Specification for the Manual Arc Welding of Carbon Steel and
Nickel Alloy**

**Hardware**

+-----------------------------------------------------------------------+
| **Engineering Directorate**                                           |
|                                                                       |
| **Structural Engineering Division**                                   |
|                                                                       |
| **November 2007**                                                     |
|                                                                       |
| ![](media/image1.png)                                                 |
|                                                                       |
| National Aeronautics and                                              |
|                                                                       |
| Space Administration                                                  |
|                                                                       |
| **Lyndon B. Johnson Space Center**                                    |
|                                                                       |
| Houston, Texas                                                        |
+-----------------------------------------------------------------------+

**Process Specification for the Manual Arc**

**Welding of Carbon Steel and Nickel Alloy**

**Hardware**

+------------------+---------------------------------+------+---------+
| **Prepared by    |                                 |      |         |
| :**              |                                 |      |         |
+------------------+---------------------------------+------+---------+
|                  | Daniel J. Rybicki               |      | Date    |
|                  |                                 |      |         |
|                  | Materials and Processes         |      |         |
|                  | Branch/ES4                      |      |         |
+------------------+---------------------------------+------+---------+

+------------------+---------------------------------+------+---------+
| **Reviewed by    |                                 |      |         |
| :**              |                                 |      |         |
+------------------+---------------------------------+------+---------+
|                  | Lucie B. Johannes               |      | Date    |
|                  |                                 |      |         |
|                  | Materials and Processes         |      |         |
|                  | Branch/ES4                      |      |         |
+------------------+---------------------------------+------+---------+

+------------------+---------------------------------+------+---------+
| **Approved by:** |                                 |      |         |
+------------------+---------------------------------+------+---------+
|                  | Bradley S. Files, Chief         |      | Date    |
|                  |                                 |      |         |
|                  | Materials and Processes         |      |         |
|                  | Branch/ES4                      |      |         |
+------------------+---------------------------------+------+---------+

  ----------- --------------------------------------------- ---------------
  REVISIONS                                                 

  VERSION     CHANGES                                       DATE

  Baseline    Original version                              6/1/95

  A           Revised version                               10/29/97

  B           Formatting, changed process owner, rewrite    07/07/99
              numerous sections for clarification, deleted  
              requirement for WIR, deleted section 8.2 on   
              audits, added section 8.3 on WPQ, deleted mil 
              specs for NDE, added PRCs for NDE.            

  C           Comprehensive technical rewrite and reformat, 9/7/00
              exclude applicability to pressurized          
              hardware, clarify 3.0, add a "D" class weld   
              in 3.1, expand design requirements, add       
              reference to NASA-SPEC-5004 and delete        
              reference to inspection/NDE PRCs, delete      
              Table II, address use of metal cored filler   
              wires in 6.1.2, clarify 6.1.4, specify        
              requirement in 6.4, clarify 6.5 to include    
              weld "rework", expand section 7.0 to clarify, 
              combine 7.2 and 7.3, revise 8.0 to clarify    
              compliance with AWS B2.1, revise all          
              acceptance criteria to clarify and simplify.  

  D           Comprehensive rewrite to combine PRC-0005 and 01/28/2004
              PRC-0006 and make editorial changes. PRC-0006 
              will be cancelled with this change. Include   
              requirements for precision cleaned hardware   
              (ref. JPG 5332.1). Expand Class D definition  
              and requirements.                             

  E           Add reference to good workmanship in section  03/09/04
              7.1.4.                                        

  F           Add reference to Class D welding in 3.0 for   11/21/2007
              on-site JSC work authorized by the JSC        
              Engineering Directorate's manufacturing       
              operations. Add additional Class D            
              stipulations in last paragraph of 3.1. Added  
              Reviewer signature block.                     
  ----------- --------------------------------------------- ---------------

#  

# **1.0 SCOPE**

This process specification provides the minimum requirements that govern
the manual arc welding of carbon steel and nickel alloy flight and non
flight hardware. Design, procedural and quality assurance requirements
are given. All work instructions and Weld Procedure Specifications (WPS)
used during welding shall satisfy the requirements of this process
specification.

# **2.0 APPLICABILITY**

This process specification applies to manual (and semiautomatic) arc
welding of carbon steel and nickel alloy flight and non flight hardware
that is fabricated under the authority of NASA/Johnson Space Center
(JSC) by any of the following types of welding processes:

a.  Gas tungsten arc welding (GTAW).

b.  Gas metal arc welding (GMAW).

c.  Flux cored arc welding (FCAW).

d.  Shielded metal arc welding (SMAW).

e.  Plasma Arc Welding (PAW).

The term "flight hardware" refers to any hardware used as a part of a
spacecraft, aircraft, or payload. The term "ground based hardware"
refers to any hardware made for facilities (buildings and related
accessories), ground support equipment, training and mockup mission
equipment, engineering prototype and development hardware, and test
equipment.

Future builds of hardware where the existing engineering documentation
calls out NASA/JSC PRC-0006 for welding shall utilize this
specification. Existing hardware fabricated to PRC-0006 requirements
shall not be affected by this change. In addition, existing engineering
documentation that specifies welding per PRC-0007 shall be accommodated
by PRC-0005, Class D. Existing hardware fabricated to PRC-0007
requirements shall not be affected by this change.

# **3.0 USAGE**

This process specification shall be invoked by including a note on the
applicable engineering drawing with the following general format which
specifies the PRC and weld class nomenclature:

**WELD AND INSPECT PER NASA/JSC PRC-0005, CLASS X.**

## 

Regarding onsite JSC work for minor facilities repair and manufacture of
shop aids that is performed under the work authorization of the JSC
Engineering Directorate\'s manufacturing operations, welds shall be
considered Class D, if they conform to the Class D weld criteria and
exclusions herein. Execution of these welds shall not require the
formality of an engineering drawing, and may be executed by verbal
orders.

## To minimize fabrication costs by avoiding over-inspection and unnecessary rework/repair, individual welds, or components on a weldment shall be classified separate where possible. This can be accomplished by including a note on the engineering drawing with the general format shown below which specifies only the PRC nomenclature. The weld class shall then be indicated by either: 1) calling out the specific weld class with the welding symbol at the individual weld joints or, 2) by using specific flag notes with the welding symbol at the individual weld joints. Refer to Figure 3.0a and 3.0b below for examples of these methods.

**WELD AND INSPECT PER NASA/JSC PRC-0005. WELD CLASSES SHALL BE AS
INDICATED AT WELD LOCATION CALLOUTS.**

## 

## 

## 

## 

## 

## **3.1 WELD CLASSIFICATION**

Welds made using this specification shall be primarily classified in
accordance with the service conditions of the weldment. The \"Class\"
governs the extent to which quality assurance provisions are applied to
the weld joint.

Alternatively, individual welds, welded connections, or entire weldments
(for simplicity, the terms weld, welded connection, and weldment will be
used interchangably) may be classified by relating the weld to the
factor of safety used in the design. However, when classifying welds in
this manner, regardless of the factor of safety, adequate consideration
should be given to the severity of the service conditions (e.g., static
loading vs. dynamic loading, cyclic, vibration, fatigue, corrosive,
extreme temp, etc.), material characteristics (e.g., ductility,
toughness, etc.), and the potential consequences of weld failure.

Where conditions exist that make it difficult to choose between 2 weld
classes, then the more stringent of the 2 classes shall be applied.

Quality assurance provisions for all weld classes are detailed in
Section 7.0. Weld classes shall be chosen on the basis of the following
definitions:

a.  [Class A]{.underline} (Flight or non flight) --- Applies to welds in
    critical load bearing elements that are not fail-safe. Class A welds
    are typically used in primary load bearing connections. Failure of a
    Class A weld in service would be catastrophic and would result in
    the loss of life, system(s), control, or major components.
    Alternatively, if it is determined from appropriate engineering
    analyses that a weld has a Factor of Safety (FSuts) vs ultimate
    tensile strength of the calculated minimum weld throat cross section
    of 2.0, it shall be designated as a Class A weld.

b.  [Class B]{.underline} (Flight or non flight) --- Applies to welds in
    load bearing elements that are fail-safe. Class B welds are
    typically used in secondary load bearing (i.e., shared load)
    connections. Failure of a Class B weld in service would reduce the
    overall efficiency of the system, but the loss of the system(s) or
    endangerment to personnel would not be expected. Alternatively, if
    it is determined from appropriate engineering analyses that a weld
    will have a FSuts of 2.0 and 3.5, it may be designated as a Class B
    weld.

c.  [Class C]{.underline} (Flight or non flight) --- Applies to welds
    that are in minor load bearing elements that are fully contained
    where failure in service would have minor or no affect on the
    efficiency of a system and endangerment to personnel would not
    occur. Class C welds are typically used in secondary or tertiary
    load bearing (i.e., shared load) connections. Alternatively, if it
    is determined from appropriate engineering analyses that a weld will
    have a FSuts of 3.5 and 5.0, it may be designated as a Class C weld.

d.  [Class D]{.underline} (Non flight hardware only) --- Applies to
    welds that are in noncritical elements and where failure would have
    no affect on the efficiency of a system and endangerment to
    personnel would not occur. Class D welds are typically used in
    connections where any expected load transfer at the weld would be
    negligible. Alternatively, if it is determined from appropriate
    engineering analyses that a weld will have a FSuts of 5.0, it may be
    designated as a Class D weld. In any case, Class D shall not be
    specified for welds used for making connections onto critical or
    primary load path elements (e.g., lift points, etc.) or elements
    directly related to personnel supporting activities, regardless of
    the loading condition/direction.

In addition to the above definitions, the following requirements shall
also apply to weld classifications:

-   If any weld intersects or overlaps another weld of a higher
    classification, then the lower classed weld shall be automatically
    upgraded to the higher of the 2 weld classes and subjected to the
    appropriate quality assurance provisions.

-   If any weld falls within ½" of any higher classed weld, then it
    shall be automatically upgraded to the higher of the 2 weld classes
    and subjected to the appropriate quality assurance provisions.

-   Class D welds are only intended for on-site (JSC) fabrication
    operations. All welds that are specified as Class D on weldments
    that are subcontracted off-site shall be recognized as Class C and
    shall be subject to all applicable Class C requirements specified
    herein. Class D welds shall only apply to welds made on common
    "structural" low carbon steels or 300 series CRES steels. HSLA,
    quenched & tempered steels, and "alloy" (e.g., chromium-molybdenum)
    steels shall not be considered for Class D welding. In addition,
    welds joining 2 or more dissimilar base metals shall not be
    allowable under Class D provisions.

## **3.2 WORK INSTRUCTIONS**

Work instructions shall be generated for implementing this process
specification. The work instructions shall contain sufficient detail to
ensure that the manufacturing process produces consistent, repeatable
results that comply with this specification. At JSC, these work
instructions are approved as Detailed Process Instructions (DPIs) that
describe in a detailed, step-by-step format the required procedures,
equipment, and materials to be used for conducting a given process. If
this manufacturing process is to be performed by an outside vendor, work
instruction development shall be the responsibility of the vendor.

## **3.3 DESIGN REQUIREMENTS**

a.  The design of welded joints (including weld sizes) shall utilize
    adequate engineering analysis methods (e.g., stress analysis,
    fracture mechanics/fracture control, etc.) to ensure that the
    resultant connection strength is capable of successfully
    transferring the maximum load expected to pass between the
    interconnecting members and meet the required factors of safety and
    design margins.

b.  All engineering drawings shall depict welded joints using the
    applicable symbols described in AWS A2.4.

c.  The engineering drawing shall specify any additional or alternate
    testing or inspection requirements. Where spot, intermittent, or
    other special inspection requirements are specified that deviate
    from those stated herein, it shall be detailed on the drawing as a
    note or by using the applicable symbology described in AWS A2.4. For
    Class A welds, alternate or reduced NDE requirements shall not be
    allowed.

d.  Class A welds are expected to be welds requiring full strength of
    the weld joint therefore, these welds shall be a groove design and
    full penetration wherever possible. The ability to successfully
    perform radiographic examination on these weld joints shall be
    considered during design.

e.  Class A welds which will be subjected to unusual or extreme service
    conditions (e.g., severe dynamic loading, cyclic, vibration, impact,
    corrosive, fatigue, extreme temp, etc.), shall be welded using a WPS
    qualified in accordance with AWS B2.1 "Special Test Weldments." This
    requirement shall be noted on the engineering drawing.

f.  Unless otherwise specified on the engineering drawing or WPS, welded
    hardware will be delivered in the "as welded" condition. If
    required, any heat treatment processing required shall be detailed
    on the engineering drawing and shall include notation that will
    reference NASA/JSC PRC-2001 or PRC-2003 as applicable.

g.  Intermittent welding (skip welds) shall not be specified for Class A
    welds.

h.  Intermittent welds shall not be specified for groove welds (square
    or prepared groove design) unless the unwelded portions of the joint
    are adequately supported to prevent one member from coming out of
    plane with the adjoining member.

# 

# **4.0 REFERENCES**

The standards listed below shall be considered a part of this
specification to the extent specified herein. Unless otherwise
indicated, the revision that is in effect on the date of invitation for
bids or the date of request for proposals shall apply.

**a. American Society of Nondestructive Testing (ASNT)**

SNT-TC-1A *Personnel Qualification and Certification in Nondestructive
Testing*

**b. American Welding Society (AWS) Standards**

ANSI/AWS A2.4 *Standard Symbols for Welding, Brazing and Nondestructive
Testing*

ANSI/AWS A3.0 *Standard Welding Terms and Definitions*

ANSI/AWS A5.X -- A5.XX *Specifications for Welding Electrodes, Rods, and
Filler Metals (Applicable to Specific Alloy and Process as governed by
this PRC)*

ANSI/AWS B2.1 *Standard for Welding Procedure and Performance
Qualification*

ANSI/AWS D1.1 *Structural Welding Code - Steel*

ANSI/AWS D1.6 *Structural Welding Code - Stainless Steel*

ANSIAWS QC-1 *Standard for AWS Certification of Welding Inspectors*

**c. Compressed Gas Association, Inc.**

G-11.1 *Argon, Commodity Specification for*

**d. Federal Documents**

BB-C-101 *Carbon Dioxide (CO~2~) : Technical and U.S.P.*

BB-H-1168 *Helium Federal Specification*

BB-O-925 *Oxygen, Technical, Gas and Liquid*

**e. Military Documents**

MIL-A-18455 *Argon, Technical*

MIL-P-27407 *Propellant Pressurizing Agent, Helium*

MIL-P-27201 *Military Specification,* *Propellant, Hydrogen*

# **f. NASA/JSC Documents**

JPG 5322.1 *Contamination Control Requirements Manual*

PRC-0008 *Process Specification for the Qualification of Manual Arc
Welders*

PRC-2001 *Process Specification for the Heat Treatment of Steel Alloys*

PRC-2003 *Process Specification for the Heat Treatment of Nickel Alloys*

SOP-004.5 *Control of Weld Filler Materials, Electrodes, and Fluxing
Materials*

SOP-007.1 *Preparation and Revision of Process Specifications*

TI-0000-04 *Training Instruction for the Welding Processes*

**g. NASA Headquarters**

NASA-SPEC-5004 *Welding of Aerospace Ground Support Equipment and
Related Nonconventional Facilities*

## 

## 

## **5.0 [MATERIAL REQUIREMENTS]{.underline}**

All materials (base and filler materials as applicable) used in the
welding of hardware per this specification, shall meet the requirements
of an applicable JSC material specification unless otherwise specified.
If a JSC material specification is not available, then an applicable
commercial specification or a manufacturer\'s specification shall be
used.

### 

### **5.1 SHIELDING GASES**

Allowable shielding gases (including purge gases) are listed in Table I.
Gases purchased to alternate specifications shall be allowed provided
they meet the minimum requirements of the specifications listed herein.
Mixtures of these gases are allowed and the nominal mixture used for the
qualification welding shall be that used for production and shall be
listed on the WPS. Shielding and purging gas mixtures shall be subject
to the qualification variable requirements listed in AWS B2.1. In
addition:

a.  Hydrogen gas in any concentration, may not be used for welding any
    alloys known to be susceptible to hydrogen related problems (e.g.,
    alloy steels, Q&T steels, martensitic stainless steels, etc.).

b.  Nitrogen shall not be used for shielding or purging in any welding
    operation governed under this specification.

c.  All gases used for shielding or purging shall have a dewpoint of
    -40°F (minus 40 °C) or better.

### **5.2 FILLER METALS AND ELECTRODES**

All filler metals shall meet the requirements of the applicable AWS
filler metal specification relative to the specific alloy and process
being used. Filler metals shall be selected from Tables II, III, and IV.
If designated in **BOLD TYPE**, this shall be the first choice for
filler metal. Otherwise, selection shall be based on specific base metal
combinations, service environment, etc.). Tubular sleeve and filler
insert materials shall have compositions similar to those indicated in
Tables II, III, and IV. In addition, the following shall apply:

a)  For dissimilar metal welds joining carbon steel to low alloy steel,
    or between two different low alloy steels, filler metal with
    strength levels matching the lower strength material shall be used.
    For dissimilar metal joints involving stainless and corrosion
    resistant steels, nickel alloys, and/or other materials, filler
    metal selection shall be based on that stated herein and approved by
    the NASA/JSC M&P organization prior to use.

b)  All filler metals shall be used in accordance with a qualified WPS.

c)  Filler metal configurations which can not be procured to an AWS or
    other applicable filler metal specification shall meet an applicable
    NASA/JSC or other industry material specification and shall be
    approved by the NASA/JSC M&P organization prior to use.

d)  Non consumable tungsten and tungsten alloy electrodes for GTAW and
    PAW shall conform to the applicable AWS specification.

e)  Filler metals shall be listed on the engineering drawing.

Table I. Allowable Shielding Gases

  ------------------- --------------------------- -----------------------
  **Gas**             **Description**             **Specification**

  Argon               Gas                         MIL-A-18455

  Argon               Type II, Grade B            CGA G-11.1
                      (Liquefied)                 

  Carbon Dioxide      Grade B                     BB-C-101

  Helium              Type I, Grade A             MIL-P-27407

  Hydrogen            Gas                         MIL-P-27201

  Oxygen              Type I                      BB-O-925
  ------------------- --------------------------- -----------------------

Table II. Approved Filler Metals for Welding Carbon and Low Alloy Steel

+----------+--------------------+--------------------+---------------+
| **MA     | **SMAW**           | **GTAW / GMAW**    | **FCAW**      |
| TERIAL** |                    |                    |               |
|          |                    | **and PAW**        |               |
| *        |                    |                    |               |
| *GROUP** |                    |                    |               |
+----------+--------------------+--------------------+---------------+
| **M-1**  | A5.1: E60XX,       | A5.28: E70S-2,     | A5.22:        |
|          | **E70XX** or       | E70S-3, **E70S-6** | **E70T-1**,   |
|          |                    |                    | E70T-5        |
|          | A5.5: E70XX-A1     |                    |               |
|          | ^(a)^              |                    |               |
+----------+--------------------+--------------------+---------------+
| **M-3**  | A5.5:              | A5.28:             | \(b\)         |
|          |                    |                    |               |
|          | E70XX-A1           | **ER80S** /        |               |
|          |                    | E80C-D2            |               |
+----------+--------------------+--------------------+---------------+
| **M-4**  | A-5.5:             | A5.28:             | \(b\)         |
|          |                    | **ER80S**,E80C-B2, |               |
|          | E80XX-B2           |                    |               |
|          |                    | ER80S / E80C-B2L   |               |
+----------+--------------------+--------------------+---------------+
| **M-5**  | A5.5:              | A5.28: **ER90S**,  | \(b\)         |
|          |                    | E80C-B3,           |               |
| **(3% Cr | E90XX-B3           |                    |               |
| max)**   |                    | ER90S / E90C-B3L   |               |
+----------+--------------------+--------------------+---------------+

> Notes:

(a) A5.5, E70XX-A1 shall be used for materials with maximum specified
    > carbon greater than 0.30%.

(b) Filler metal to be used for joining must be compositionally
    > compatible with base metal. Primary consideration shall be given
    > to mechanical properties, corrosion resistance, and weldability,
    > as applicable for the specific application.

> Table III. Approved Filler Metals for Welding Nickel Alloys

+-------------------+-------------------------+-----------------------+
| **BASE METAL**    | **SMAW**                | **GTAW / GMAW / PAW** |
|                   |                         |                       |
|                   | **(AWS A5.11)**         | **(AWS A5.14)**       |
+-------------------+-------------------------+-----------------------+
| **Nickel 200**    | ENi-1                   | ERNi-1                |
|                   |                         |                       |
| **Nickel 201**    |                         |                       |
+-------------------+-------------------------+-----------------------+
| **Monel 400**     | ENiCu-7                 | ERNiCu-7              |
+-------------------+-------------------------+-----------------------+
| **Monel K500**    | \--                     | ERNiCu-7              |
+-------------------+-------------------------+-----------------------+
| **Inconel 600**   | **ENiCrFe-1**,          | **ERNiCrFe-5**,       |
|                   | ENiCrFe-3               | ERNiCr-3              |
+-------------------+-------------------------+-----------------------+
| **Inconel 601**   | **ENiCrFe-3**,          | **ERNiCr-3**,         |
|                   | ENiCrMo-3               | ERNiCrMo-3            |
+-------------------+-------------------------+-----------------------+
| **Inconel 625**   | ENiCrMo-3               | ERNiCrMo-3            |
+-------------------+-------------------------+-----------------------+
| **Inconel 718**   | \--                     | ERNiFeCr-2            |
|                   |                         |                       |
| **Inconel X750**  |                         |                       |
+-------------------+-------------------------+-----------------------+
| **Incoloy 800**   | **ENiCrFe-2**,          | **ERNiCr-3,**         |
|                   | ENiCrCoMo-1             | ERNiCrCoMo-1          |
+-------------------+-------------------------+-----------------------+
| **Incoloy 800HT** | ENiCrFe-2               | ERNiCr-3              |
+-------------------+-------------------------+-----------------------+
| **Incoloy 825**   | \--                     | ERNiFeCr-1            |
+-------------------+-------------------------+-----------------------+
|                   |                         |                       |
+-------------------+-------------------------+-----------------------+

**Table IV. Approved Filler Metals for Welding Austenitic Stainless
Steel**

+---------+------+------+--------+--------+--------+---------+-------+
| **AWS   | **3  | **30 | *      | *      | *      | *       | **    |
| M-8**   | 04** | 4L** | *309** | *310** | *316** | *316L** | 321** |
|         |      |      |        |        |        |         |       |
| **Base  | **3  |      |        |        |        |         | **    |
| M       | 08** |      |        |        |        |         | 347** |
| etal:** |      |      |        |        |        |         |       |
|         |      |      |        |        |        |         | **    |
|         |      |      |        |        |        |         | 348** |
+---------+------+------+--------+--------+--------+---------+-------+
| **301** | 308  | 308  | 308    | 308    | 308    | 308     | 308   |
|         |      |      |        |        |        |         |       |
| **302** | **30 | **30 | 308L   | 308L   | 308L   | 308L    | **3   |
|         | 8L** | 8L** |        |        |        |         | 08L** |
| **304** |      |      | 309    | 309    | 316    | 316     |       |
|         |      |      |        |        |        |         |       |
| **308** |      |      | **     | **     | **     | *       |       |
|         |      |      | 309L** | 309L** | 316L** | *316L** |       |
|         |      |      |        |        |        |         |       |
|         |      |      |        | 310    |        |         |       |
+---------+------+------+--------+--------+--------+---------+-------+
| *       | 308  | **30 | 308    | 308    | 308    | 308L    | **3   |
| *304L** |      | 8L** |        |        |        |         | 08L** |
|         | **30 |      | 308L   | 308L   | 308L   | *       |       |
|         | 8L** |      |        |        |        | *316L** | 347   |
|         |      |      | 309    | 309    | 316    |         |       |
|         |      |      |        |        |        | 309L    |       |
|         |      |      | **     | **     | **     |         |       |
|         |      |      | 309L** | 309L** | 316L** |         |       |
|         |      |      |        |        |        |         |       |
|         |      |      |        | 310    |        |         |       |
+---------+------+------+--------+--------+--------+---------+-------+
| **309** |      |      | 309    | 309    | 309    | 309     | 309   |
|         |      |      |        |        |        |         |       |
|         |      |      | **     | **     | 309L   | 309L    | **3   |
|         |      |      | 309L** | 309L** |        |         | 09L** |
|         |      |      |        |        | 316    | 316     |       |
|         |      |      |        | 310    |        |         | 347   |
|         |      |      |        |        | **     | *       |       |
|         |      |      |        |        | 316L** | *316L** |       |
+---------+------+------+--------+--------+--------+---------+-------+
| **310** |      |      |        | 310    | 316    | 316     | 308   |
|         |      |      |        |        |        |         |       |
|         |      |      |        |        | **     | *       | 308L  |
|         |      |      |        |        | 316L** | *316L** |       |
|         |      |      |        |        |        |         | **    |
|         |      |      |        |        | 310    | 310     | 310** |
+---------+------+------+--------+--------+--------+---------+-------+
| **316** |      |      |        |        | 316    | 316     | 308   |
|         |      |      |        |        |        |         |       |
|         |      |      |        |        | **     | *       | 308L  |
|         |      |      |        |        | 316L** | *316L** |       |
|         |      |      |        |        |        |         | 316   |
|         |      |      |        |        |        |         |       |
|         |      |      |        |        |        |         | **3   |
|         |      |      |        |        |        |         | 16L** |
+---------+------+------+--------+--------+--------+---------+-------+
| *       |      |      |        |        |        | 309L    | 309L  |
| *316L** |      |      |        |        |        |         |       |
|         |      |      |        |        |        | *       | **3   |
|         |      |      |        |        |        | *316L** | 16L** |
+---------+------+------+--------+--------+--------+---------+-------+
| **321** |      |      |        |        |        |         | 309L  |
|         |      |      |        |        |        |         |       |
| **347** |      |      |        |        |        |         | 321   |
|         |      |      |        |        |        |         |       |
| **348** |      |      |        |        |        |         | **    |
|         |      |      |        |        |        |         | 347** |
+---------+------+------+--------+--------+--------+---------+-------+

**5.2.1 [Control and Storage]{.underline}**

Welding electrodes shall be stored in a clean, dry, and controlled area
that provides protection from contamination, physical damage, and
commingling of alloys. Any form of electrodes or weld filler metal which
is damaged, dirty, exhibits oxidation/corrosion or has been contaminated
with water, oil, grease or any form of hydrocarbons shall not be used
and shall be disposed of in accordance with an appropriate disposal
procedure. For JSC operations, welding electrodes and filler materials
shall be controlled in accordance with EM-004.5. Outside vendors shall
provide control and storage according to the applicable material
specification or manufacturer\'s recommendation, whichever is more
rigid.

# 

# **PROCESS REQUIREMENTS**

All weldments shall be fabricated according to the requirements of this
process specification and shall be performed using Welding Procedure
Specifications (WPS) that have been qualified in accordance with the
requirements of Section 8.1 except for that as detailed below.

Class D welds may be performed without the use of a specific qualified
WPS within the following restrictions:

a)  all other provisions of this specification are met,

b)  the filler metal/electrodes used shall be within the same F-Number
    group of fillers as those used for the other higher classed welds in
    the same weldment or as approved by the responsible M&P Engineering
    organization where the only welds in the weldment design are Class
    D,

c)  the filler metal shall be compositionally compatible with the base
    metal(s), and

d)  welding shall be conducted within the recommendations of the
    specific filler metal manufacturer.

    1.  **Welding Precision Cleaned Hardware (including tube preparation
        for welding)**

Whenever precision-cleaned hardware must be maintained clean during
welding into an assembly, the welding operation shall be performed in a
dedicated Class 100,000 Clean Work Area. This may require temporary
tents over the weld area and/or local monitors located in the area of
welding to ensure the Class 100,000 environment is being met. Portable
particle counters shall be located as close as possible to the work
area, so as to monitor local contaminants during tube preparation and
welding. Tools used in weld preparation and welding (such as cutter,
weld head, files) shall be visibly cleaned per JPG 5322.1 and maintained
clean (e.g. bagged when not in use).

For hardware that cannot be subsequently precision-cleaned, a proven
method for protecting against system contamination during tube
preparation and welding shall be implemented. One such method is the use
of a physical barrier, such as plugs. The installation and removal of
plugs shall be tracked by a reliable method and independently verified.
Prior to plug removal, the exposed internal surfaces of the tube shall
be cleaned using a swab wetted with an approved solvent, and positive
backpressure shall be maintained as the plug is removed.

Tube cutters shall use a sharp blade, changed frequently. Cutting shall
be performed with minimal cutter pressure to aid in preventing particle
generation. Vacuum shall be used during tube facing operations to remove
particulate. Whenever possible, facing operations shall be performed
away from the weld assembly area, to reduce particulate contamination of
the welding work area. Tube facing shall be performed without the use of
cutting oils, other fluids, lubricants or coolants. Abrasives, including
sandpaper or abrasive pads, shall not be used inside tubes or when
unprotected internal surfaces are exposed. After each tube preparation,
and prior to welding, a high-velocity gas purge shall be performed. The
purge gas velocity shall be the maximum attainable using a 90-psig
source. The purge gas used during facing and welding shall meet the
hydrocarbon and particulate requirements for the system under assembly.
The purge gas shall be supplied in accordance with Section 5.1.

## 

## **PROCESS-SPECIFIC REQUIREMENTS**

Applicable to all processes, weld joints that are specified for
intermittent welding shall have the ends of the parts, or departure from
a straight weld line (e.g., square corner, etc.), welded regardless of
the interval of the weld.

1.  **[Gas Tungsten Arc Welding]{.underline}**

Additional filler metal shall be used with the GTAW process unless it
can be demonstrated by weld qualification that weld cracking and other
undesirable metallurgical conditions will not exist in the finished weld
made without filler metal (autogenous weld). This method of welding
shall be specified on an approved WPS.

### **Gas Metal Arc Welding**

This process shall be recognized to include both solid and metal cored
wires.

The GMAW short circuiting transfer mode shall not be used for welding of
flight hardware nor to join materials of greater than ¼" thickness
unless specifically qualified and documented in a WPS. Thickness
limitations for this process mode shall be as specified by AWS B2.1. The
process can be used to deposit the root and additional passes in the
root region of butt joints exceeding that specifically qualified for, up
to a deposited weld metal thickness as allowed by the WPS. The GMAW
short circuiting transfer mode shall not be used to make Class A welds.

## 

2.  **[Flux Cored Arc Welding]{.underline}**

## 

This process shall be recognized to include both self shielding and dual
shielding filler metals.

### 

### **Shielded Metal Arc Welding**

Base metals known to be susceptible to hydrogen related problems shall
utilize only low hydrogen coated electrodes with this process.

### **Plasma Arc Welding**

Additional filler metal shall be used with the PAW process unless it can
be demonstrated by weld qualification that weld cracking and other
undesirable metallurgical conditions will not exist in the finished weld
made without filler metal (autogenous weld). This method of welding
shall be specified on an approved WPS.

### 

## **6.3 PREHEATING**

Preheat shall not exceed the temperature specified in the applicable
WPS. In weld joints between different base metal types and/or
thicknesses, the higher of the preheat requirements of the joint members
shall apply.

## 

## **6.3.1 Interpass Temperature**

In weld joints between different base metal types and/or thicknesses,
the higher of the interpass temperature requirements of the joint
members shall apply. Minimum interpass temperature during welding shall
be the same as the preheat temperature specified in the WPS and shall be
maintained by the application of concurrent heat as necessary. The
maximum interpass temperature for welding quenched & tempered steels
shall be at least 50^o^ F below the nominal tempering temperature.

## 

## **POST-WELD HEAT TREATMENT (PWHT)**

Postweld heat treatment, when required by the engineering drawing or
WPS, shall be performed after completion of all welding in accordance
with NASA/JSC PRC-2001 or PRC-2003, as applicable. Vibratory techniques
shall not be used in place of thermal treatments. All postweld
inspections shall be applied immediately following all post weld heat
treatment activities with the exception of ASTM A514, A517, and A709
Grades 100 and 100W. Inspection of welds made on these alloys shall not
occur less than 48 hours after welding.

## **WELD REPAIRS AND WELDED REPAIRS TO BASE METAL**

All weld rework and welded repairs shall be performed using the WPS used
for the original weld, a specific qualified WPS for that repair, or as
approved by the responsible M&P engineering organization. Rework and
repairs shall meet all of the requirements of the original drawing and
any additional requirements documented in the WPS. Weld rework and
repair does not include the correction of dimensional or other
deficiencies of the groove/bevel preparation of weld joints by
"buttering" or build up provided the area corrected by welding is fully
consumed in the final weld. Also, the following requirements shall apply
in the weld repair activity:

a.  [Defect Removal]{.underline}. Defect removal shall be by means of
    grinding, chipping, machining, thermal gouging or a combination of
    these methods. Except on low carbon steels, thermal gouging, and
    cutting performed with carbon based electrodes shall require the
    excavated cavity be finished by grinding to sound metal. The final
    repair cavity shall be of a configuration suitable for welding. The
    excavation shall be subjected to visual and/or other NDE
    examinations to ensure defect removal prior to welding. Weld repairs
    shall be adequately documented by the use of a weldment map or other
    record with sufficient detail to ensure identification of the
    weldment, identification of repair location(s), and type of defect.

b.  [Repair]{.underline}. No more than two weld attempts shall be made
    to successfully repair a rejected flaw. If a second attempt is
    unsuccessful, a discrepancy report shall be generated and shall
    require dispositioning by the responsible Material Review Board
    (MRB). The level of documentation of repair welds shall, at a
    minimum, be consistent with that required for the original
    production weld.

c.  [Straightening]{.underline}. Welds or adjacent base metal which have
    been deformed by the welding operation may be straightened. All
    straightening operations shall take place at temperatures not to
    exceed the determined critical temperature for that alloy. All
    straightening operations shall be performed prior to any final
    inspection.

d.  [Base Metal Repairs.]{.underline} Repairs to base metal anomalies
    shall be brought to the attention of the NASA/JSC M&P organization
    for consideration of cause, prior to repair activities.

# **7.0 PROCESS VERIFICATION**

Process verification shall consist of nondestructive examination(s)
(NDE), as described in sections 7.1 to 7.3. In addition, the
manufacturer shall assure that the fabrication activities are carried
out in a manner that meets the requirements of this process
specification.

## 

## **7.1 INSPECTION**

Unless otherwise specified in design documentation, all inspections
(examinations) detailed herein are required to include all welds in a
structure. Any temporary welds, unconsumed tack welds, etc. shall be
subjected to the level of inspection required by the highest weld class
specified on the design documentation.

1.  **[Class A Inspection]{.underline}**

```{=html}
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```
a)  Class A welds require visual (VT), surface, and subsurface NDE.
    Surface inspections shall be accomplished using the liquid penetrant
    (PT) or magnetic particle (MT) inspection process and shall be
    performed per AWS D1.1 for carbon and low alloy steels and AWS D1.6
    for all other alloys welded to this specification. Unless otherwise
    specified, PT shall utilize Type I, Level 3 or 4 and MT shall
    utilize the wet fluorescent continuous method. Results of all
    surface inspections for Class A joints shall utilize the Class A
    acceptance criteria in Appendix A. Subsurface inspections shall be
    accomplished using the radiographic (RT) inspection process and
    shall be performed per AWS D1.1 for carbon and low alloy steels and
    AWS D1.6 for all other alloys welded to this specification. In
    either case, unless otherwise specified, the acceptance criteria
    shall be as listed for "Cyclically Loaded" tension welds (and
    "Tubular" or "Nontubular" connections as applicable for conditions
    subjected to AWS D1.1) in each applicable AWS code.

b)  In cases where the Class A inspection is designated for any weld
    having a configuration which renders adequate RT methods
    impractical, an alternate examination method shall be utilized as
    approved by the responsible NASA/JSC M&P engineering organization.

c)  When the PT method is selected and approved as a complete alternate
    to RT for multipass welds, inspections shall be performed on the
    root pass, each 1/4" thick layer of weld metal, and the final or
    cover pass.

d)  When the ultrasonic (UT) inspection method is selected as an
    alternate to RT, it shall be performed per AWS D1.1 for carbon and
    low alloy steels and AWS D1.6 for all other alloys welded to this
    specification. In either case, unless otherwise specified, the
    acceptance criteria shall be as listed for "Cyclically Loaded"
    tension welds (and "Tubular" or "Nontubular" connections as
    applicable for conditions subjected to AWS D1.1) in each applicable
    AWS code.

**7.1.2 [Class B Inspection]{.underline}**

Unless otherwise specified in design documentation, Class B welds
require VT and surface NDE only. Surface inspections shall be
accomplished using the PT or MT inspection process and shall be
performed per AWS D1.1 for carbon and low alloy steels and AWS D1.6 for
all other alloys welded to this specification. Results of all surface
inspections for Class B joints shall utilize the Class B acceptance
criteria in Appendix A. Unless otherwise specified, PT shall utilize
Type II and MT shall utilize the dry continuous method.

**7.1.3 [Class C Inspection]{.underline}**

Unless otherwise specified in design documentation, Class C welds
require VT only. Results of all VT inspections for Class C joints shall
utilize the Class C acceptance criteria in Appendix A.

### **7.1.4 Class D Inspection** 

Unless otherwise specified in design documentation, Class D welds
require only inspection to verify the type, nominal size, length,
location, and that the welds were left in a condition exhibiting good
workmanship practices. Good workmanship shall be defined as the presence
of uniform appearance and overall clean weld zones and the absence of
spatter, arc strikes, tool marks, and other obvious discontinuities that
would likely be questionable. Where a size is not specified, the nominal
weld size shall be per best shop practice and at the discretion of the
manufacturing organization with the intent to utilize single pass welds
wherever possible so as to avoid over-welding. A CWI is not required for
this inspection. This level of inspection may serve as a means of "in
process" or "self verification" where design and/or manufacturing
protocols permit.

## **7.2 VISUAL EXAMINATION REQUIREMENTS**

All visual inspections (VT) of Class A, B, and C welds shall be
performed by an American Welding Society (AWS) Certified Welding
Inspector (CWI). The CWI certification must be current. Inspection of
Class D welds do not require a CWI.

## **7.3 NON-DESTRUCTIVE EVALUATION (NDE)**

The NDE of welded joints shall be performed by personnel qualified in
accordance with the requirements of the applicable NDE process
specification. The NDE certification must be current. All nondestructive
inspections shall be performed in accordance with the appropriate
standards as referenced herein.

**8.0 PROCESS DOCUMENTATION REQUIREMENTS**

The WPS, PQR, and WPQ shall be prepared and retained as a permanent
record and made available upon request to the NASA/JSC M&P organization
for review. One copy of the WPS shall be maintained in the vicinity of
the welding station and shall be readily accessible by the welding,
inspection, supervision, and engineering personnel.

## 

**8.1 WELDING PROCEDURE SPECIFICATION**

A Welding Procedure Specification (WPS) is a qualified written working
procedure used in production that must be developed before beginning
production for each unique weld type to be produced. Qualification
support documentation in the form of a Procedure Qualification Record
(PQR) shall be qualified by appropriate testing and maintained on file
to show proof of process/procedure capability for using the WPS. The WPS
shall be traceable by means of serialized nomenclature and shall show
traceability to the applicable PQR(s). The WPS used for production
welding shall meet the requirements of AWS B2.1 and shall be certified
by the responsible M&P organization at the operating facility, prior to
use in production. If a qualified WPS does not exist prior to welding of
production parts, one shall be qualified according to AWS B2.1 "Standard
Test Weldments", at a minimum.

## 

**8.2 PROCEDURE QUALIFICATION RECORD**

A Procedure Qualification Record (PQR) is documentation to support the
WPS to show proof of process/procedure capability. A PQR shall be unique
and traceable, by means of serialized nomenclature. The PQR shall be
process-specific and specific to a unique weld type. The PQR shall meet
the requirements of AWS B2.1 and shall be certified by the responsible
M&P organization at the operating facility.

## **8.3 WELDER PERFORMANCE QUALIFICATION**

A Welder Performance Qualification (WPQ) is documentation showing that a
welder has been tested in accordance with the governing specification
and shown competent to produce a sound weld for a specific welding
process/base metal/filler metal/position combination. NASA/JSC PRC-0008
is the governing document for personnel performance qualifications
required by this specification.

# **9.0 TRAINING AND CERTIFICATION OF PERSONNEL**

## **9.1 TRAINING**

At JSC, if welder training is considered necessary prior to
qualification/requalification of existing JSC welding personnel or for
the initial qualification of new hires, it shall be conducted in
accordance with TI-0000-04. For an outside JSC vendor, welder training
(when necessary) should consist of practice using the facility welding
equipment and a specific WPS to demonstrate proficiency, under the
supervision of a qualified/certified welder. Specific development of an
appropriate training program shall be the responsibility of the vendor.

## **9.2 WELDER QUALIFICATION**

Welding shall be performed by a welder qualified and certified in
accordance with NASA/JSC PRC-0008. Sufficiently detailed records shall
be maintained to demonstrate continuity of performance qualification on
a semi-annual (6 month) basis.

## **10.0 [DEVIATIONS AND WAIVERS]{.underline}**

Any deviations or waivers regarding the use of this process
specification shall be requested in writing. This request shall be
directed to the NASA/JSC M&P organization with the appropriate
justification and rationale. A written response will be provided upon
such a request.

**Appendix A**

**[WELD INSPECTION CRITERIA]{.underline}**

**[GENERAL]{.underline}** If any of the inspection conditions listed
herein conflict with the requirements of the engineering drawing, then
the more strict criteria shall govern. Pertinent to this Appendix, the
designation 'T' shall mean the nominal base metal thickness of the
thinnest component in the welded connection. Unless otherwise stated,
the criteria in this Appendix shall apply to all weld classes except
Class D. Acceptance criteria for Class D welds is detailed only in
Section 7.1 of this specification. Alternate and/or additional
acceptance criteria may be used for any weld class however, it shall be
specified in the design documentation.

**A1.0 [SIZE AND APPEARANCE]{.underline}**

**A1.1 GROOVE WELDS**

**[All Classes]{.underline} -** The minimum weld size shall be the size
(i.e., size = effective weld throat) specified on the drawing. If
profile requirements are not specified, the weld shall be convex or
flat. Weld profile requirements do not apply at the ends of groove welds
provided any concavity is gradually sloped and evidence of good
workmanship exists in regards to weld terminations. Where a size is not
specified, the penetration requirement shall be 100%. Reinforcement
requirements shall be as specified below.

**[Class A]{.underline} -** If profile requirements are not specified,
the weld shall be convex.

**A1.2 [FILLET WELDS]{.underline}**

**[All Classes]{.underline} -** The minimum weld size shall be the size
specified on the drawing (i.e., size = leg size). If profile
requirements are not specified, the weld may be slightly concave, flat,
or convex. However, concave profiles shall have at least the minimum
throat for the size of weld specified. Weld profile requirements do not
apply at the ends of fillet welds provided any concavity is gradually
sloped and evidence of good workmanship exists in regards to weld
terminations. For intermittent welding, the ends being exempt from these
profile requirements shall be outside the specified effective weld
length. Where a size is not specified, the weld size shall be a minimum
of 75% of the thickness of the thinner component. Reinforcement
requirements shall be as specified below.

**[Class A and B]{.underline} -** The weld size may fall below the size
specified by up to 1/16" or T/4, whichever is less, for 10% of the total
weld length ^(1)^.

**[Class C]{.underline} -** The weld size may fall below the size
specified by up to 1/16" or T/3, whichever is less, for 30% of the total
weld length ^(1)^.

(1) The weld length shall be the distance from end to end of the weld
    deposit or to a sharp change in direction of the weld where the
    angle of change in any direction is greater than 30 degrees at a
    radius of \<1/2".

**A2.0 [WELD REINFORCEMENT]{.underline}**

**A2.1 GROOVE AND FILLET WELDS**

Weld reinforcement (face and root) shall not exceed that specified in
Table A2.1a.

**TABLE A2.1a -- Weld Reinforcement Height Limits**

  ----------------------------------- -----------------------------------
  **Weld Face Width**                 **Reinforcement Height**

  **¼"**                              **1/16"**

  **¼" and ¾"**                       **1/8"**

  **¾" and 1-3/4"**                   **3/16"**

  **1-3/4"**                          **¼"**
  ----------------------------------- -----------------------------------

**A3.0 MISALIGNMENT AND PEAKING (angular misalignment)**

**[Class A]{.underline} -** Misalignment shall not exceed T/10 or 1/8",
whichever is less. Peaking shall not exceed 3^O^.

**[Class B]{.underline} -** Misalignment shall not exceed T/5 or 3/16",
whichever is less. Peaking shall not exceed 5^O^.

> Note - Where both misalignment and peaking exist as a combined
> condition in the same weld, either of the 2 conditions must not exceed
> ½ that stated above in order to be determined to be acceptable.

**A4.0 SURFACE DISCOLORATION AND OXIDATION**

Weld zones shall not exhibit a burned appearance or contain loose
oxidation or scale attributable to atmospheric contamination.

**A5.0 SURFACE ROUGHNESS**

**[Class A and Class B]{.underline} --** On mechanically dressed (e.g.,
ground, sanded, etc.) weld and adjacent surfaces within ½" of the weld
toe, surface roughness shall not exceed 125 in.

**A6.0 DISCONTINUITIES**

**[All Classes]{.underline} -** Weld discontinuities exceeding the
maximum allowable sizes for the applicable Class in Table A6.0 shall not
be allowed. Elongated discontinuities shall be defined as having a
length to width ratio of 3:1. Rounded discontinuities shall be defined
as having a length to width ratio 3:1.

For base metal thicknesses (T) 1/8", the following shall apply to Table
A6.0a:

> **[Class A]{.underline} -** Any discontinuity, except cracks and
> undercut, 0.01" at its greatest dimension, shall not be considered.
>
> **[Class B]{.underline} -** Any discontinuity, except cracks and
> undercut, 1/32" at its greatest dimension, shall not be considered.
>
> **[Class C]{.underline} -** Any discontinuity, except cracks and
> undercut, 1/16" at its greatest dimension, shall not be considered.

**TABLE A6.0 - Maximum Allowable Discontinuity Sizes**

  -------------- ----------------- ---------------- ---------------- ----------------
  **LINEITEM**   **DISCONTINUITY   **Class A**      **Class B**      **Class C**
                 TYPE**                                              

  **1**          **Cracks in the   None allowed     None allowed     None allowed
                 weld or base                                        
                 metal (e.g.,                                        
                 longitudinal,                                       
                 transverse,                                         
                 crater, toe,                                        
                 etc.) ^(1)^**                                       

  **2**          **Undercut Depth  0.01" or 0.1T,   1/32" or 0.33T,  1/16" or 0.33T,
                 ^(1)^**           whichever is     whichever is     whichever is
                                   less             less ^(3)^       less ^(3)^

  **3**          **Arc Strike**    None allowed     None allowed     n/a

  **4**          **Spatter**       None allowed     None allowed     n/a

  **5**          **Elongated       None allowed     3/32" or 0.4T in 1/8" or 0.6T in
                 ^(1)^**                            length,          length,
                                                    whichever is     whichever is
                                                    less ^(4)^ Sum   less ^(4)^ Sum
                                                    of all visible   of all visible
                                                    indications      indications
                                                    shall be 3/8" or shall be 1/2" in
                                                    T in length,     length, in any
                                                    whichever is     1" of weld
                                                    less, in any 1"  length and 1.75"
                                                    of weld length   in any 12" of
                                                    and 3/4" in any  weld length
                                                    12" of weld      ^(5)^
                                                    length ^(5)^     

  **6**          **Rounded ^(1)^** Surface: 1/16"   3/32" or 0.4T    1/8" or 0.6T
                                   or 0.3T          diameter         diameter,
                                   diameter,        whichever is     whichever is
                                   whichever is     less ^(2)^ Sum   less ^(2)^ Sum
                                   less ^(2)^       of all visible   of all visible
                                                    indications      indications
                                                    shall be 3/8" or shall be 1/2" in
                                                    1.5T in length,  any 1" of weld
                                                    whichever is     length and 1.75"
                                                    less, in any 1"  in any 12" of
                                                    of weld length   weld length
                                                    and 3/4" in any  ^(5)^
                                                    12" of weld      
                                                    length ^(5)^     
  -------------- ----------------- ---------------- ---------------- ----------------

(1) For all discontinuities approaching a free edge (See Figure A6.0
    below) that are being considered, the closest edge of the
    discontinuity shall have clearance from the free edge 3X the largest
    of its dimensions or, 2X the nominal weld throat, whichever is
    greater.

(2) *Adjacent rounded discontinuities separated by 1X the length of the
    longer discontinuity shall be considered a single discontinuity.*

(3) *Undercut may be 2X the value permitted, but never to exceed 1/16",
    for a continuous or accumulated length of 2" in any 12" weld length
    or 15% of the total weld length where the weld length is less than
    12".*

(4) Adjacent elongated discontinuities separated by 3X the diameter of
    the larger discontinuity, shall be considered a single
    discontinuity.

(5) For weld lengths less than 12", the total sum of indications shall
    be an equivalent proportion of the weld length, to that given.

![](media/image2.png){width="2.422222222222222in"
height="1.9618055555555556in"}

C = Clearance spacing between closest edge of discontinuity and free
edge

**FIGURE A6.0 -- [DISCONTINUITY APPROACHING FREE EDGE]{.underline}**