NUREG/CR–6428

ANL–95/47

Effects of Thermal Aging on

Fracture Toughness and

Charpy–Impact Strength of

Stainless Steel Pipe Welds

Manuscript Completed: November 1995

Date Published: May 1996

Prepared by

D. J. Gavenda, W. F. Michaud, T. M. Galvin, W. F. Burke, and O. K. Chopra

Argonne National Laboratory

9700 South Cass Avenue

Argonne, IL 60439

M. E. Mayfield, NRC Project Manager

Prepared for

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, DC 20555

NRC FIN A2212
NUREG/CR–6428 ii
iii NUREG/CR–6428

Effects of Thermal Aging on Fracture Toughness and Charpy–Impact Strength

of Stainless Steel Pipe Welds

by

D. J. Gavenda, W. F. Michaud, T. M. Galvin,

W. F. Burke, and O. K. Chopra

Abstract

The degradation of fracture toughness, tensile, and Charpy–impact properties of Type 308

stainless steel (SS) pipe welds due to thermal aging has been characterized at room temperature and 290°C. Thermal aging of SS welds results in moderate decreases in Charpy–impact

strength and fracture toughness. For the various welds in this study, upper–shelf energy decreased by 50–80 J/cm2. The decrease in fracture toughness J–R curve or JIC is relatively

small. Thermal aging had little or no effect on the tensile strength of the welds. Fracture properties of SS welds are controlled by the distribution and morphology of second–phase particles.

Failure occurs by the formation and growth of microvoids near hard inclusions; such processes

are relatively insensitive to thermal aging. The ferrite phase has little or no effect on the fracture properties of the welds. Differences in fracture resistance of the welds arise from differences in the density and size of inclusions. Mechanical–property data from the present study

are consistent with results from other investigations. The existing data have been used to establish minimum expected fracture properties for SS welds.
NUREG/CR–6428 iv
v NUREG/CR–6428

Contents

Executive Summary ........................................................................................................ xi

Acknowledgments .......................................................................................................... xiii

1 Introduction ................................................................................................................. 1

2 Material Characterization .............................................................................................. 2

3 Mechanical Properties ................................................................................................... 3

3.1 Charpy–Impact Energy .................................................................................... 7

3.2 Tensile Properties ........................................................................................... 14

3.3 Fracture Toughness ........................................................................................ 16

4 Conclusions ................................................................................................................. 23

References .................................................................................................................... 25

Appendix: J–R Curve Characterization .............................................................................. 29

Figures

1. Typical ferrite morphology of the various welds of this study .............................. 4

2. Configuration of Charpy–impact test specimen ................................................... 5

3. Configuration of compact–tension test specimen ................................................ 5

4. Orientation and location on weldments where mechanical test specimens were

taken .............................................................................................................. 6

5. Variations in ferrite content of PWWO weld ........................................................ 7

6. Effect of therm al aging on Charpy–transition curve for PWWO weld ..................... 9

7. Charpy–impact energy of unaged and aged stainless steel welds ......................... 9

8. Photomicrographs of fracture surface of unaged and aged Charpy specimens

of various welds tested at room temperature..................................................... 13
NUREG/CR–6428 vi

9. Higher–magnification photomicrographs of fracture surface of unaged and

aged Charpy specimens of PWWO and PWDR welds tested at room

temperature .................................................................................................... 14

10. Photomicrograph of fracture surface of unaged Charpy specimen of PWWO

weld tested at –180°C...................................................................................... 15

11. Tensile yield and ultimate stress of stainless steel welds ..................................... 16

12. Fracture toughness J–R curve for PWCE weld at room temperature and 290°C ...... 18

13. Fracture toughness J–R curve for PWWO weld at room temperature and 290°C .... 19

14. Fracture toughness J–R curve fo r PWER weld at 290°C ....................................... 20

15. Fracture toughness J–R curves for stainless steel welds at room temperature

and 288–427°C ............................................................................................... 21

16. Fracture toughness J–R curves for aged stainless steel welds at room

temperature and 288°C.................................................................................... 22

17. Fracture toughness JIC for unaged and aged stainless steel welds ........................ 23

18. Fracture toughness J–R curves represented by Eqs. 3 and 4 and the data for

aged CF–3 and 316L welds and that in the technical basis document for ASME

Code IWB–3640 analysis................................................................................... 24

A–1. Fracture surface of unaged weld metal PWCE tested at 25°C ............................... 36

A–2. Deformation J–R curve for unaged weld metal specimen PWCE–02 tested at

25°C ............................................................................................................... 37

A–3. Modified J–R curve for unaged weld metal specimen PWCE–02 tested at 25°C ...... 37

A–4. Fracture surface of aged weld metal PWCE tested at 25°C .................................. 40

A–5. Deformation J–R curve for weld metal specimen PWCE–04 aged at 400°C for

10,000 h and tested at 25°C........................................................................... 41

A–6. Modified J–R curve for weld metal specimen PWCE–04 aged at 400°C for

10,000 h and tested at 25°C........................................................................... 41

A–7. Fracture surface of unaged weld metal PWCE tested at 290°C ............................. 44

A–8. Deformation J–R curve for unaged weld metal specimen PWCE–01 tested at

290°C ............................................................................................................. 45
vii NUREG/CR–6428

A–9.Modified J–R curve for unaged weld metal specimen PWCE–01 tested at 290°C......... 45

A–10. Fracture surface of aged weld me tal PWCE tested at 290°C ................................ 48

A–11. Deformation J–R curve for weld metal specimen PWCE–03 aged at 400°C for

10,000 h and tested at 290°C......................................................................... 49

A–12. Modified J–R curve for weld metal specimen PWCE–03 aged at 400°C for

10,000 h and tested at 290°C......................................................................... 49

A–13. Fracture surface of aged weld metal PWWO tested at 25°C ................................. 52

A–14. Deformation J–R curve for weld metal specimen PWWO–03 aged at 400°C for

7,700 h and tested at 25°C............................................................................. 53

A–15. Modified J–R curve for weld metal specimen PWWO–03 aged at 400°C for

7,700 h and tested at 25°C............................................................................. 53

A–16. Fracture surface of unaged weld metal PWWO tested at 290°C ........................... 56

A–17. Deformation J–R curve for unaged weld metal specimen PWWO–01 tested at

290°C ............................................................................................................. 57

A–18. Modified J–R curve for unaged weld metal specimen PWWO–01 tested at

290°C ............................................................................................................. 57

A–19. Fracture surface of aged weld metal PWWO tested at 290°C ............................... 60

A–20. Deformation J–R curve for weld metal specimen PWWO–04 aged at 400°C for

7,700 h and tested at 290°C........................................................................... 61

A–21. Modified J–R curve for weld metal specimen PWWO–04 aged at 400°C for

7,700 h and tested at 290°C........................................................................... 61

A–22. Fracture surface of aged weld metal PWWO tested at 290°C ............................... 64

A–23. Deformation J–R curve for weld metal specimen PWWO–02 aged at 400°C for

7,700 h and tested at 290°C........................................................................... 65

A–24. Modified J–R curve for weld metal specimen PWWO–02 aged at 400°C for

7,700 h and tested at 290°C........................................................................... 65

A–25. Fracture surface of aged weld metal PWER tested at 290°C ................................ 68

A–26. Deformation J–R curve for weld metal specimen PWER–01 aged at 400°C for

10,000 h and tested at 290°C......................................................................... 69
NUREG/CR–6428 viii

A–27. Modified J–R curve for weld metal specimen PWER–01 aged at 400°C for

10,000 h and tested at 290°C......................................................................... 69

Tables

1. Composition and ferrite content of austenitic stainless steel welds ...................... 2

2. Charpy–impact test results for stainless steel welds ........................................... 8

3. Summary of mechanical–property data for austenitic stainless steel welds ........... 10

4. Tensile yield and ultimate stress of various stainless steel welds, estimated

from Charpy–impact data ................................................................................. 15

5. Fracture toughness test results for unaged and aged austenitic stainless steel

weldments....................................................................................................... 17

A–1. Test data for specimen PWCE–02 ...................................................................... 34

A–2. Deformation J IC and J–R curve results for specimen PWCE–02 ............................. 35

A–3. Modified JIC and J–R curve results for specimen PWCE–02 ................................... 36

A–4. Test data for specimen PWCE–04 ...................................................................... 38

A–5. Deformation J IC and J–R curve results for specimen PWCE–04 ............................. 39

A–6. Modified JIC and J–R curve results for specimen PWCE–04 ................................... 40

A–7. Test data for specimen PWCE–01 ...................................................................... 42

A–8. Deformation J IC and J–R curve results for specimen PWCE–01 ............................. 43

A–9. Modified J IC and J–R curve results for specimen PWCE–01 ................................... 44

A–10. Test data for specimen PWCE–03 ...................................................................... 46

A–11. Deformation J IC and J–R curve results for specimen PWCE–03 ............................. 47

A–12. Modified JIC and J–R curve results for specimen PWCE–03 ................................... 48

A–13. Test data fo r specimen PWWO–03 .................................................................... 50

A–14. Deformation J IC and J–R curve results for specimen PWWO–03 ........................... 51

A–15. Modified JIC and J–R curve results for specimen PWWO–03 ................................. 52
ix NUREG/CR–6428

A–16. Test data for specimen PWWO–01 .................................................................... 54

A–17. Deformation J IC and J–R curve results for specimen PWWO–01 ........................... 55

A–18. Modified JIC and J–R curve results for specimen PWWO–01 ................................. 56

A–19. Test data for specimen PWWO–04 .................................................................... 58

A–20. Deformation J IC and J–R curve results for specimen PWWO–04 ........................... 59

A–21. Modified JIC and J–R curve results for specimen PWWO–04 ................................. 60

A–22. Test data for specimen PWWO–02 .................................................................... 62

A–23. Deformation J IC and J–R curve results for specimen PWWO–02 ........................... 63

A–24. Modified JIC and J–R curve results for specimen PWWO–02 ................................. 64

A–25. Test data for specimen PWER–01 ...................................................................... 66

A–26. Deformation J IC and J–R curve results for specimen PWER–01 ............................. 67

A–27. Modified JIC and J–R curve results for specimen PWER–01 ................................... 68
NUREG/CR–6428 x
xi NUREG/CR–6428

Executive Summary

Stainless steels (SSs) are used extensively in light water reactor (LWR) systems because of

their excellent ductility, high notch toughness, corrosion resistance, and good formability.

Although these steels are completely austenitic in the wrought condition, welded and cast SSs

have a duplex structure consisting of austenite and ferrite phases. The ferrite phase provides

additional benefits, e.g., it increases tensile strength and improves the resistance to stress corrosion cracking. However, the duplex steels are susceptible to thermal embrittlement after extended service at reactor operating temperatures, i.e., typically 282°C (540°F) for boiling water

reactors, 288–327°C (550–621°F) for pressurized water reactor (PWR) primary coolant piping,

and 343°C (650°F) for PWR pressurizers.

It is well established that thermal embrittlement of cast duplex SSs at reactor temperatures increases hardness and tensile strength; decreases ductility, impact strength, and fracture

toughness; and shifts the Charpy transition curve to higher temperatures. Thermal embrittlement is caused primarily by formation of the Cr–rich α' phase in the ferrite and, to some

extent, by precipitation and growth of carbides at phase boundaries. It results in brittle fracture associated with either cleavage of the ferrite or separation of the ferrite/austenite phase

boundary. Predominantly brittle failure occurs when either the ferrite phase is continuous

(e.g., in material with a large ferrite content) or the ferrite/austenite phase boundary provides

an easy path for crack propagation (e.g., in materials with high C content). The amount, size,

and distribution of the ferrite phase in the duplex structure, and the presence of phase–boundary carbides are important parameters in controlling the degree or extent of thermal embrittlement.

A procedure and correlations have been developed for estimating fracture toughness, tensile, and Charpy–impact properties of cast SS components during service from known material

information. Although SS welds have a duplex structure and their chemical compositions are

similar to those of cast SSs, the estimation scheme is not applicable to SS welds. The degradation of fracture toughness, tensile, and Charpy–impact properties of Type 308 pipe welds due

to thermal aging has been characterized in this report. The welds were aged for 7,000–

10,000 h at 400°C to simulate saturation conditions, i.e., lowest impact energy that would be

achieved by the material after long–term aging. The results have been compared with fracture–

property data from other studies.

Thermal aging of the SS welds resulted in moderate decreases in Charpy–impact strength

and fracture toughness at both room temperature and 290°C. For the various welds, USE decreased by 50–80 J / cm2 (30–47 ft·lb.). The decrease in the fracture toughness J–R

curve or JIC is relatively small. Metallographic examination of the specimens indicates that

failure occurs by the formation and growth of microvoids near hard inclusions. Differences in

the fracture resistance of the welds arises from differences in the density and size of inclusions.

In this study, the effect of thermal aging on fracture properties is minimal because of the

relatively low ferrite content (4–6% ferrite) and thin vermicular ferrite morphology in the welds.

The Charpy–impact, tensile, and fracture toughness results from this study have been

compared with available data on SMAWs, SAWs, and GTAWs prepared with Types 308 or 316

SS filler metal. The data are consistent with results from other investigations. The fracture

properties of SS welds are insensitive to filler metal. The welding process has a significant ef-
NUREG/CR–6428 xii

fect. In general, GTAWs exhibit higher fracture resistance than SMAWs or SAWs, and there is

no difference between SAW and SMAW J–R curves. The Charpy–impact energy of some welds

may be as low as 40 J.

The results indicate that the decrease in impact strength due to aging depends on the

ferrite content and initial impact strength of the weld. Welds with relatively high strength show

a large decrease whereas those with poor strength show minimal change. In SS welds with

poor strength, failure occurs by the formation and growth of microvoids. Such processes are

relatively insensitive to thermal aging. The existing data indicate that at reactor temperatures,

the fracture toughness JIC of thermally aged welds can be as low as 40 kJ/m2. A conservative

estimate of J–R curve for aged SS welds may be given by J = 40 + 83.5 Δa0.643.
xiii NUREG/CR–6428

Acknowledgments

This work was supported by the Office of the Nuclear Regulatory Research in the U.S.

Nuclear Regulatory Commission (NRC), under FIN A2212, Program Manager: Michael McNeil.
NUREG/CR–6428 xiv
1 NUREG/CR–6428

1 Introduction

Stainless steels (SSs) are used extensively in light water reactor (LWR) systems because of

their excellent ductility, high notch toughness, corrosion resistance, and good formability.

Although these steels are completely austenitic in the wrought condition, welded and cast SSs

have a duplex structure consisting of austenite and ferrite phases. The ferrite phase provides

additional benefits, e.g., it increases tensile strength and improves resistance to stress corrosion cracking. However, duplex steels are susceptible to thermal embrittlement after extended

service at reactor operating temperatures, i.e., typically 282°C (540°F) for boiling water reactors, 288–327°C (550–621°F) for pressurized water reactor (PWR) primary coolant piping, and

343°C (650°F) for PWR pressurizers.

It is well established1–7 that thermal aging of cast SSs at 250–350°C (482–662°F) increases

hardness and tensile strength; decreases ductility, impact strength, and fracture toughness;

and shifts the Charpy transition curve to higher temperatures. Aging of cast SSs at temperatures <500°C (<932°F) leads to precipitation of additional phases in the ferrite, e.g., formation

of a Cr–rich α' phase by spinodal decomposition; nucleation and growth of α'; precipitation of a

Ni– and Si–rich G phase, M23C6, and γ2 (austenite); and additional precipitation and/or growth

of existing carbides at ferrite/austenite phase boundaries.8–12 Thermal embrittlement is

caused primarily by formation of the Cr–rich α' phase in the ferrite and, to some extent, by

precipitation and growth of carbides at phase boundaries. Thermal embrittlement of cast SSs

results in brittle fracture associated with either cleavage of the ferrite or separation of the ferrite/austenite phase boundary. Predominantly brittle failure occurs when either the ferrite

phase is continuous (e.g., in cast material with a large ferrite content) or the ferrite/austenite

phase boundary provides an easy path for crack propagation (e.g., in high–C grades of cast

steel with large phase–boundary carbides). The amount, size, and distribution of the ferrite

phase in the duplex structure, and the presence of phase–boundary carbides are important parameters in controlling the degree or extent of thermal embrittlement. In general, the low–C

CF–3 steels are the most resistant to thermal embrittlement, and the Mo–bearing, high–C CF–

8M steels are the least resistant. The extent of thermal embrittlement increases with increased

ferrite content.

A procedure and correlations have been developed at Argonne National Laboratory (ANL)

for estimating fracture toughness, tensile, and Charpy–impact properties of cast SS components during service from known material information.13,14 The ANL estimation scheme is

applicable to compositions within the ASTM Specifications A 351 for Grades CF–3, CF–3A, CF–8,

CF–8A, and CF–8M. A correlation for Charpy–impact energy at saturation, i.e., the mini

mum impact energy that would be achieved for the material after long–term aging, is given in

terms of chemical composition. Change in impact energy as a function of time and temperature

of service is estimated from saturation impact energy and from the correlations that describe

the kinetics of embrittlement, which are also given in terms of chemical composition. The

fracture toughness J–R curve for the material is then obtained from the correlation between the

fracture toughness parameters and the Charpy–impact energy. Tensile yield and

flow stresses, and Ramberg/Osgood parameters are estimated from the flow stress of the unaged material and the kinetics of embrittlement.3

Although SS welds have a duplex structure and their chemical compositions are similar to

those of cast SSs, the ANL correlations are not applicable to these welds. The ANL correlations
NUREG/CR–6428 2

account for mechanical–property degradation of typical heats of cast SS. They do not consider

the effects of compositional or structural differences that may arise from differences in processing or heat treatment of the steels. Type 308 SS welds generally contain 5–15% ferrite but

their mechanical properties typically differ from those of cast SSs. For a given ferrite content,

the tensile strength of SS welds is higher and fracture toughness is lower than that of cast SSs.

Experimental data15 indicate that cast SSs with poor fracture toughness are relatively insensitive to thermal aging, i.e., fracture toughness of the material would not change significantly

during service. In these steels, failure is controlled by void formation near inclusions or other

flaws in the material, i.e., by processes that are not sensitive to thermal aging. These results

suggest that SS welds with poor fracture toughness, e.g., shielded metal arc welds (SMAWs) or

submerged arc welds (SAWs), should be relatively insensitive to thermal aging.

Degradation of fracture toughness and Charpy–impact energy of several SS pipe welds has

been characterized in this report. The welds were aged for 7,000–10,000 h at 400°C to simulate saturation conditions, i.e., the lowest impact energy that would be achieved by the material

after long–term aging. The results are compared with data from other studies.

2 Material Characterization

Five pipe weldments were procured for the study. The composition and ferrite content of

the welds are given in Table 1. The ferrite content was measured with a ferrite scope and calculated from the chemical composition in terms of Hull's equivalent factors.16 Fabrication and

procurement history of the weldments is as follows:

PWWO: 12–in. Type 304 Schedule 100 pipe mockup weldment with overlays was supplied by

Georgia Power and NUTECH.17 The weld was fabricated with Type 308L filler metal and conventional butt welding procedures. On one side of the weld the prep geometry of the weld was

long and smooth, i.e., typical of that used in the Hatch–1 reactor. On the other side, the prep

geometry was short, typical of that used in the Hatch–2 reactor. The overlay was similar to

that applied to the recirculation piping in the Hatch–2 reactor.

PWCE: 28–in., Type 304/308 pipe weldment was obtained from the Boston Edison Power Co.

Table 1. Composition and ferrite content of austenitic stainless steel welds

Material Composition (wt.%) Ferriteb ( % )

IDa C N Si Mn P S Ni Cr Mo Cu Calc. Meas.

PWWO 0.030 0.072 0.44 2.12 0.018 0.018 10.72 20.35 0.27 0.20 4.1 6.8

PWCE 0.050 0.060 0.44 1.79 0.003 0.002 9.54 20.22 0.05 0.04 5.4 6.1

PWER 0.020 0.074 0.36 1.78 0.018 0.009 10.29 20.12 0.19 0.12 4.8 5.2

PWDR 0.080 – 0.75 1.00 0.022 0.010 9.74 20.72 0.08 0.08 5.9 –

PWMS 0.021 – 0.40 1.61 0.025 0.006 9.56 19.80 0.19 0.11 8.3 –

a PWWO: 12–in. schedule 100 pipe mockup weldment with overlays supplied by Georgia Power and NUTECH.

PWCE: 28–in.–diameter Type 304 stainless steel pipe weldment obtained from Boston Edison.

PWER: 20–in.–diameter Type 304 stainless steel pipe weldment prepared for EPRI at Southwest Fabricating.

PWDR: 10–in.–diameter Type 304 stainless steel weldment after service in Dresden reactor.

PWMS: 28–in.–diameter pipe weldment treated by Mechanical Stress Improvement Process (MSIP). b Calculated from the composition with Hull's equivalent factor.

Measured by Ferrite Scope, Auto Test FE, Probe Type FSP–1.
3 NUREG/CR–6428

PWER: 20–in., Type 304/308 pipe weldment was supplied by the Electric Power Research

Institute (EPRI). It was prepared at Southwest Fabricating by the heat sink welding (HSW)

technique.18

PWDR: 10–in., Type 304 SS pipe weldment was obtained from the emergency core–spray system of the Dresden–2 reactor. It was prepared by shielded metal arc welding with coated electrodes; the root pass was made by gas tungsten arc welding. The insert and filler metals were

Type ER308. The pipe had been in service for ≈4.5 y. Water temperature in the core spray line

is 204–260°C during normal operation.1 9

PWMS: 28–in., seamless Type 304 SS pipe weldment was treated by the Mechanical Stress

Improvement Process (MSIP).20 The filler metal was Type ER308L. The MSIP treatment is intended to produce a more favorable state of residual stress on the inner surface of the pipe

welds, particularly near heat–affected zones. The weld undergoes monotonic compressive

loading that is produced by a split–ring–like tool mounted on the pipe. The favorable residual

stresses are induced by plastic compression of the weld.

Although the welding process is not specified for all of the weldments, the welds of large–

diameter pipes are typically prepared by shielded metal arc welding. All of the welds consisted

of a duplex austenite and ferrite structure; the ferrite phase was at the core of the dendritic

branches in the weld. Typical microstructures of the welds are shown in Fig. 1. All of the

welds exhibit a vermicular ferrite morphology. The ferrite content of the welds is relatively low

(in the range of 4–6%).

3 Mechanical Properties

Charpy–impact tests were conducted on standard V–notch specimens (Fig. 2) according to

American Society for Testing and Materials (ASTM) Specification E 23. A Dynatup Model 8000A

drop–weight impact machine with an instrumented tup and data readout system was used for

the Charpy–impact tests. Load– and energy–time data were obtained from an instrumented tup

and recorded on a dual–beam storage oscilloscope. The load–time traces from each test were

digitized and stored on a floppy disk for analysis. Total energy was computed from the load–

time trace; the value was corrected for the effects of tup velocity.

The instrumented tup and data readout instrumentation were calibrated by fracturing

standard V–notch specimens fabricated from 6061–T6 Al and 4340 steel with a hardness of

Rockwell RC 54. Accuracy of the impact–test machine was also checked with Standard

Reference Materials 2092 and 2096 obtained from the National Institute of Standards and

Technology. Tests on the reference materials were performed in accordance with the testing

procedures of Section 1 1 of ASTM E23. The specimens for high–temperature tests were heated

by resistance heating. Pneumatic clamps were used to make electrical connections and hold

the specimens in position on the anvils. The temperature was monitored and controlled by

a thermocouple attached to the specimen. Specimens for the low–temperature tests were

cooled in either a refrigerated bath or liquid N.

The fracture toughness J–R curve tests were conducted according to ASTM Specification

E 1152–87. Compact–tension specimens (Fig. 3), 25.4 mm thick, were used for the tests. The

experimental procedure and data for the fracture toughness tests are given in the Appendix.
NUREG/CR–6428 4

Figure 1. Typical ferrite morphology of the various welds of this study
5 NUREG/CR–6428

A

± 1°

± .001 .394

125

.394± .001

SCALE:

6 : 1

.010 R

± .001

125

63

A .001

B .001

B

 45°

DETAIL A

 A

A .001

.315

63

1.082

± .001

± .010

2.165

 +.000

 - .010

63

125 125

Figure 2. Configuration of Charpy–impact test specimen: units of measure are inches

C .002

.230

1.308

B .002

A .005

A A .002

B

A .002

SCALE:

2" = 1"

.376

HOLES - 2 PLACES

'C'

.093 CT. BORE X .06 DP

 2-56 UNC TAP X .25 DP

 TYP. 4 PLACES

.460 .654

.280 .640

.320 1.200

2.400

2.500

± .010

2.000

.900

.120

1.000

.625

.187

40 ± 2

.005

.045 .090

.005 R

MAX.

DETAIL 'C'

64

.140

xxxx-

 xx

+.005

-.000 DIA. THRU

1.

2.

3.

4.

C .002

C

A .002

C .002

A .002

SPECIMEN AND MATERIAL

SHALL BE IDENTIFIED WITH 

SPECIMEN I.D. NUMBER DURING ALL

MACHINING PROCESSES.

ALL SURFACES TO BE FREE OF

BURRS.

ALL MACHINED SURFACES .

DECIMAL TOLERANCES ±.005

UNLESS OTHERWISE NOTED.

Figure 3. Configuration of compact–tension test specimen: units of measure are inches
NUREG/CR–6428 6

The orientation and location on the weldment where the Charpy–impact and fracture

toughness test specimens were taken are shown in Fig. 4. In all cases, the fracture plane is in

the center of the weld. The variation in ferrite content in the center of all of the welds was minimal; the variation in the PWWO weld is shown in Fig. 5. Some of the materials were aged in

the laboratory for 8,000–10,000 h at 400°C (752°F) to simulate the saturation condition, i.e.,

the condition when the lowest impact strength is achieved by the material after long–term service at reactor temperatures.

~1-3/16

PIPE INSIDE

SURFACE

WELD

WELD

~1-1/4

~4-7/8

WELD

WELD

~9/16

PIPE INSIDE

SURFACE

~2-5/8 ~5-3/4

(a) (b)

~1

PIPE INSIDE

SURFACE

WELD

~6-5/8 ~7-1/4

(c)

Figure 4. Orientation and location on weldments where mechanical test specimens were taken:

(a) and (c) ≥1 in.–thick pipe sections and (b) <1 in.–thick pipe sections
7 NUREG/CR–6428

4.5

6.1

5.7

6.2

6.0

5.6

3.6

4.0

4.2

5.5

5.5

6.3

5.0

Figure 5. Variations in ferrite content of PWWO weld

3.1 Charpy–Impact Energy

Charpy impact data for the PWCE, PWWO, PWDR, and PWMS welds are given in Table 2.

A complete Charpy transition curve was obtained only for the PWWO weld; other welds were

tested at room temperature and 290°C. Transition curves for the unaged and aged PWWO weld

are shown in Fig. 6. The Charpy data were fitted with a hyperbolic tangent function of the form

CV = Ko + B 1 + tanh T – C

D

⎛

⎝

⎞

⎠

⎡

⎣

⎢ ⎤

⎦

⎥, (1)

where K o is the lower–shelf energy, T is the test temperature in °C, B is half the distance between the upper– and lower–shelf energy, C is the mid–shelf Charpy transition temperature

(CTT) in °C, and D is the half width of the transition region. The results indicate that thermal

aging increased the mid–shelf CTT by 47°C, i.e., from –105°C to –58°C, and decreased upper–

shelf energy (USE) by 50 J/cm2 (30 ft·lb.).

The Charpy–impact data for aged materials represent the saturation condition, i.e., the

condition when the lowest impact strength is achieved by the material after long–term service

at reactor temperatures. The results indicate that thermal aging results in moderate decreases

in impact energy at both room temperature and 290°C. For the various welds, USE decreased

by 50–80 J/cm2 (30–47 ft·lb); from 1 8 7 t o 137 J/cm2 (110 t o 8 1 ft·lb) for PWWO, from 353 t o

271 J/cm2 (208 to 160 ft·lb) for PWCE, and from 169 t o 9 8 J/cm2 (100 to 58 ft·lb) for

PWDR. Similar decreases were observed at room temperature. Even in the fully embrittled

condition, all of the welds exhibit adequate impact strength, e.g., >90 J/cm2 (53 ft·lb) at 290°C

and >75 J/cm2 (44 ft·lb) at room temperature.

The results are consistent with the data from other investigations. Mechanical–property

data on Charpy–impact, tensile, and fracture toughness properties of SMAWs, SAWs, and gas

tungsten arc welds (GTAWs) prepared from Types 308 or 316 filler metal are compiled in

Table 3.21–38 The Charpy–impact data for unaged and aged welds are shown in Fig. 7. The results for unaged welds show large variation; impact energy of some welds may be as low as
NUREG/CR–6428 8

Table 2. Charpy–impact test results for stainless steel welds

Test

Number

Specimen

ID

Aging

Temp.

( °C)

Aging

Time

( h )

Test

Temp.

( °C)

Impact

Energy

( J / c m 2 )

Yield Load

( k N )

Maximum

Load

( k N )

CS-2878 PWWO-05 - - - 1 8 0 59.2 17.615 23.493

CS-2880 PWWO-06 - - - 1 0 0 100.8 14.598 19.607

CS-2879 PWWO-07 - - - 5 0 125.4 16.121 21.335

CS-2863 PWWO-08 - - 2 5 175.1 12.928 17.244

CS-2864 PWWO-09 - - 2 5 162.8 14.539 19.588

CS-2875 PWWO-10 - - 7 5 212.2 11.512 16.092

CS-2876 PWWO-11 - - 1 5 0 186.4 12.284 16.053

CS-2871 PWWO-12 - - 2 9 0 189.7 8.622 12.108

CS-2872 PWWO-13 - - 2 9 0 183.4 10.145 13.866

WIN-2882 PWWO-14 4 0 0 7 , 7 0 0 - 1 9 7 9.8 13.836 13.836

WIN-2883 PWWO-15 4 0 0 7 , 7 0 0 - 1 8 0 9.5 14.285 14.285

WIN-2884 PWWO-16 4 0 0 7 , 7 0 0 - 1 0 0 44.1 15.594 18.474

WIN-2885 PWWO-17 4 0 0 7 , 7 0 0 - 5 0 82.9 16.248 20.437

WIN-2886 PWWO-18 4 0 0 7 , 7 0 0 0 111.3 13.973 18.347

WIN-2887 PWWO-19 4 0 0 7 , 7 0 0 2 5 126.3 14.412 18.221

WIN-2888 PWWO-20 4 0 0 7 , 7 0 0 2 5 130.9 13.397 17.879

WIN-2893 PWWO-21 4 0 0 7 , 7 0 0 7 5 157.4 13.163 17.430

WIN-2894 PWWO-22 4 0 0 7 , 7 0 0 1 5 0 143.4 11.512 15.428

WIN-2895 PWWO-23 4 0 0 7 , 7 0 0 2 0 0 152.4 11.542 15.340

WIN-2896 PWWO-24 4 0 0 7 , 7 0 0 2 9 0 121.8 9.540 13.153

WIN-2897 PWWO-25 4 0 0 7 , 7 0 0 2 9 0 151.9 10.575 14.305

CS-2861 PWCE-05 - - 2 5 255.6 12.948 18.855

CS-2862 PWCE-06 - - 2 5 281.9 11.776 18.533

WIN-2889 PWCE-09 4 0 0 10,000 2 5 187.2 13.524 19.011

WIN-2890 PWCE-10 4 0 0 10,000 2 5 149.3 12.167 17.937

CS-2869 PWCE-07 - - 2 9 0 340.5 9.149 12.577

CS-2870 PWCE-08 - - 2 9 0 366.0 7.890 12.430

WIN-2898 PWCE-11 4 0 0 10,000 2 9 0 291.7 10.155 14.178

WIN-2899 PWCE-12 4 0 0 10,000 2 9 0 250.8 8.544 14.334

CS-2865 PWDR-06 - - 2 5 138.7 12.616 17.537

CS-2866 PWDR-07 - - 2 5 140.2 12.791 17.859

WIN-2891 PWDR-01 4 0 0 10,000 2 5 78.8 12.938 15.184

WIN-2892 PWDR-02 4 0 0 10,000 2 5 84.4 12.821 15.028

CS-2873 PWDR-08 - - 2 9 0 148.4 8.310 11.893

CS-2874 PWDR-09 - - 2 9 0 189.5 8.515 12.596

WIN-2900 PWDR-03 4 0 0 10,000 2 9 0 93.4 8.583 11.493

WIN-2901 PWDR-04 4 0 0 10,000 2 9 0 102.4 8.866 12.303

CS-2859 PWMS-01 - - 2 5 191.4 13.885 18.953

CS-2860 PWMS-02 - - 2 5 185.6 13.504 18.861

CS-2867 PWMS-03 - - 2 9 0 202.7 9.872 13.524

CS-2868 PWMS-04 - - 2 9 0 186.9 9.159 12.977
9 NUREG/CR–6428

0

50

100

150

200

250

-300 -200 -100 0 100 200 300 400

Unaged

Aged

Temperature (°F)

100

75

50

25

0

125

Temperature (°C)

Im

p

a

ct E

n

erg

y, C

V (J/cm2

)

Im

p

a

ct E

n

erg

y, C

V (ft·lb)

–500 –300 –100 100 300 500 700

Mid–Shelf

CTT (°C)

–105

–58

(J/cm2)

195

145

USE

Figure 6. Effect of thermal aging on Charpy–transition curve for PWWO weld

0

100

200

300

400

0 100 200 300 400

308 SMAW

308 SAW

308 GTAW

316 SMAW

316 SAW

316 GTAW

Present Study

C

h

arp

y

–Im

p

a

ct E

n

erg

y (J)

Temperature (°C)

0 100 200 300 400

308 SMAW

308 GTAW

Present Study

Temperature (°C)

Closed Symbols: Aged

Figure 7. Charpy–impact energy of unaged and aged stainless steel welds
NUREG/CR–6428 1 0

Table 3. Summary of mechanical–property data for austenitic stainless steel welds

Authors Ref.

Mater.

&

Processa

Heat

Treat–

mentb

Ferrite

Content

( F N / % )

Test

Temp.

(°C)c

Impact

Energy

( J ) d

Yield

Strength

(MPa)

Ultimate

Strength

(MPa)

JIC

( k J / m 2 )

Tearing

Modulus

Horn, et al. 2 2 308, SMAW – RT 1 2 2 ,

1 1 1

– – – –

2 8 8 1 0 7 3 1 5 4 4 9 194, 215 –

SA RT – – – – –

2 8 8 2 2 4 1 9 2 4 2 5 1 6 9 –

316, SAW – RT 7 3 – – – –

2 8 8 95, 103 3 0 9 4 3 4 1 7 0 –

SA RT – – – – –

2 8 8 1 0 8 1 9 2 4 0 1 2 2 1 –

Chipperfield 2 4 316, SMAW – 7.0–9.0 3 7 0 7 1 4 0 1 4 8 6 5 6 –

a 3.5–6.5 3 7 0 6 9 2 8 6 4 3 1 42, 50 –

b 1.0–3.0 3 7 0 8 7 2 6 1 4 2 3 4 0 –

c 0–0.5 3 7 0 1 2 5 1 8 4 4 4 9 6 7 –

Ould, et al. 2 5 316L, MMAW/ I 8.5 2 0 63, 54 4 6 8 6 0 5 – –

SAW 3 4 3 – 3 5 6 4 7 1 – –

F 7.5 2 0 51, 62 4 6 5 6 1 3 – –

3 4 3 – 3 7 5 4 7 4 – –

H1 7.5 2 0 56, 58 4 2 5 5 9 2 147, 168 –

3 4 3 – 3 7 9 4 6 4 – –

308L, MMAW/ C 6.0 2 0 62, 51 439, 452 541, 544 – –

SAW 3 4 3 – 344, 363 391, 390 – –

B 6.0 2 0 49, 51 420, 436 535, 545 1 5 3 –

3 4 3 – 325, 341 385, 390 – –

D 5.0 2 0 58, 51 3 9 8 5 6 3 1 3 0 –

3 4 3 – 324, 345 394, 431 – –

Landes & 2 6 308, SAW – 2 4 111, 68 3 4 8 6 0 0 8 1 1 9 0

McCabe 2 8 8 148, 62 2 4 8 4 2 6 4 7 1 5 0

308, GTAW – 2 4 1 9 0 354, 475 595, 624 1 9 5 6 1 0

2 8 8 3 2 4 239, 372 429, 437 5 5 8 5 0 0

308, SMAW – 2 4 9 6 432, 414 605, 597 2 5 9 1 7 0

2 8 8 1 1 4 323, 341 423, 446 1 6 8 1 4 0

316, SAW – 2 4 8 8 4 1 4 6 3 3 1 1 6 1 2 0

2 8 8 4 6 2 8 1 4 8 5 1 0 5 9 0

Mi l l s 2 7 , 308, SMAW – 6.8 2 4 – 4 5 5 6 3 4 – –

2 8 , 4 2 7 – 3 2 3 4 7 2 1 5 4 ± 4 1 3 1 0

2 9 5 3 8 – 3 0 3 4 1 2 1 5 4 ± 4 1 3 1 0

308, GTAW – 9.9 4 2 7 – 2 7 8 4 7 7 2 6 6 ± 2 0 3 7 3

5 3 8 – 2 6 8 4 0 1 2 6 6 ± 2 0 3 7 3

308, SAW – 10.7 2 4 – 3 6 5 6 2 7 1 9 8 ± 1 7 1 0 7

4 2 7 – 3 4 4 4 7 4 7 6 ± 1 7 1 6 7

5 3 8 – 2 9 0 3 8 4 7 6 ± 1 7 1 6 7

16–8–2, GTAW – 5.7 2 4 – 3 6 0 6 6 8 392± 1072 4 9

4 2 7 – 2 6 5 3 8 8 2 6 6 ± 2 0 3 7 3

4 8 2 – 2 8 1 3 8 5 2 6 6 ± 2 0 3 7 3

5 3 8 – 2 6 3 3 5 9 2 6 6 ± 2 0 3 7 3

16–8–2, SAW – 9.0 2 4 – 3 9 1 6 2 7 1 9 8 ± 1 7 1 0 7

4 2 7 – 2 9 7 4 7 6 7 6 ± 1 7 1 6 7

5 3 8 – 3 2 1 4 3 9 7 6 ± 1 7 1 6 7
1 1 NUREG/CR–6428

Table 3. (Contd.)

Authors Ref.

Mater.

&

Processa

Heat

Treat–

mentb

Ferrite

Content

( F N / % )

Test

Temp.

(°C)c

Impact

Energy

( J ) d

Yield

Strength

(MPa)

Ultimate

Strength

(MPa)

JIC

( k J / m 2 )

Tearing

Modulus

Vitek, et al. 3 0 308L, GTAW – 10.0 2 5 208, 136

143, 192

3 9 9 ± 5 6 6 0 6 ± 2 4 480, 773 –

1 5 0 1 9 2 ,

166, 204

– – – –

Alexander, 3 1 308, SMAW – 4.0 RT 1 0 6 – –

et al. 1 4 0 1 0 9 – – – –

8.0 RT 9 0 – –

1 4 0 9 8 – – – –

12.0 RT 8 7 – –

1 4 0 9 9 – – – –

Hale & 3 2 308L, SMAW – 5–9 2 4 6 3 4 9 7 ± 2 4 6 0 6 ± 1 1 – –

Garwood 3 0 0 8 2 – – 9 2 ± 2 5 7 5

Garwood 3 3 316, SAW – 3 7 0 – 3 2 5 4 7 3 1 2 0 –

316, MMAW – 3 7 0 – 3 8 6 4 7 1 7 0 –

Vassilaros, 3 4 308L, GTAW – RT – 4 6 5 6 1 2 5 2 1 2 8 9

et al. 1 4 9 – 3 5 6 4 7 6 4 0 0 2 7 7

2 8 8 – 3 3 8 4 5 2 1 6 3 ,

227, 375

1 5 2 ,

363, 437

Gudas & 3 5 308L, SMAW – RT – – – 243, 168109, 105

Anderson 1 4 9 – – – 159, 96 89, 71

2 8 8 – – – 214, 174134, 121

Hawthorne 3 6 308, SMAW – 5.2 2 4 8 7 4 7 8 6 2 8 – –

& Menke 2 6 0 1 1 0 3 8 2 4 7 4 – –

4 8 2 1 0 8 3 2 5 4 3 0 – –

10.4 2 4 7 7 5 3 4 6 9 3 – –

2 6 0 1 0 0 4 2 0 5 2 1 – –

4 8 2 – 3 5 8 4 7 8 – –

15.7 2 4 6 6 5 1 8 6 8 3 – –

2 6 0 9 6 4 1 5 5 2 1 – –

4 8 2 9 2 3 6 2 4 8 2 – –

19.0 2 4 8 0 5 5 7 7 1 8 – –

2 6 0 1 0 7 4 4 7 5 6 3 – –

4 8 2 1 0 2 3 7 6 5 1 7 – –

316, SAW – 7–10.5 2 4 – –

2 6 0 – –

Faure, et al. 3 7 316L, GTAW – 2 4 1 1 1 ,

124, 128

507, 518 603, 626 – –

1 0 0 1 2 9 ,

133, 155

458, 482 536, 552 2 8 1 –

3 0 0 1 3 3 ,

135, 144

409, 415 470, 480 2 1 5 –

Wilkowski, 3 8 308, SAW – 2 8 8 3 2 5 4 6 6 – –

et al. SA 2 8 8 1 9 5 4 6 5 – –

Nagasaki,

et al.

3 9 308, GTAW – 2 8 8 2 9 8 4 4 7 – –
NUREG/CR–6428 1 2

Table 3. (Contd.)

Authors Ref.

Mater.

&

Processa

Heat

Treat–

mentb

Ferrite

Content

( F N / % )

Test

Temp.

(°C)c

Impact

Energy

( J ) d

Yield

Strength

(MPa)

Ultimate

Strength

(MPa)

JIC

( k J / m 2 )

Tearing

Modulus

European

Community

4 0 316, GMAW – 2 0 159, 165

148, 165

151, 151

518, 361 644, 607 – –

5 5 0 193, 264

209, 209

219, 159

217, 151 428, 402 – –

316, MMAW – 2 0 77, 73 469, 469,

428, 437

585, 586,

608, 608

– –

5 5 0 77, 82 292, 307,

178, 178

403, 413,

421, 422

– –

316, SAW – 2 0 87, 92,

7 7

397, 407,

405, 347,

359, 358

566, 568,

567, 584,

596, 590

– –

5 5 0 64, 87,

8 7

– – – –

a SMAW: Shielded metal arc weld; SAW: Submerged arc weld; MMAW: Manual metal arc weld; and

GTAW: Gas tungsten arc weld. b SA: solution annealed; other designations are heat treatment code that are defined in the reference. c RT: room temperature. d All values represent impact energy for a standard Charpy V–notch specimen, i.e., 10 x 10 mm size.

50 J (37 ft·lb). The GTAWs generally exhibited higher impact strength than the SMAWs or

SAWs. The results indicate that the welds that were investigated in the present study have

relatively high impact strength; the PWCE weld exhibited the highest and PWDR the lowest impact strength.

In Fig. 7 the impact energies of aged welds25,30–32 fall within the large scatter band of the

unaged welds. The results indicate that the effect of thermal aging on Charpy–impact strength

depends on the initial impact strength of the welds. Welds with relatively high impact strength,

e.g., the GTAWs, show a large decrease in impact energy whereas those with poor impact

strength show minimal change in impact energy. Even in the saturation or fully embrittled

condition, austenitic SS welds have ≥50 J (3 7 ft·lb) of impact energy.

Photomicrographs of the fracture surface of unaged and aged weld metal Charpy specimens tested at room temperature are shown in Fig. 8. The results indicate that the overall

fracture behavior of the welds is controlled by the distribution and morphology of second–

phase particles. All welds exhibit a dimple fracture. Failure occurs by nucleation and growth of

microvoids and rupture of remaining ligaments. High–magnification photomicrographs of

unaged and aged PWWO and PWDR specimens are presented in Fig. 9, which shows that

nearly every dimple was initiated by decohesion of an inclusion (most likely manganese sili

cide). The hard inclusions in the SMAW resist deformation and the buildup of high local

stresses leads to decohesion of the particle/matrix interface. Inferior fracture resistance of the

PWDR weld may be attributed to the higher density and larger size of inclusions relative to the

PWWO or PWCE welds. Metallographic results suggest that the delta ferrite phase has relatively

little effect on the fracture properties of the welds.

The results also indicate that thermal aging has no effect on fracture morphology of the

specimens tested at room temperature; both unaged and aged welds exhibit a dimple fracture.
1 3 NUREG/CR–6428

Figure 8. Photomicrographs of fracture surface of unaged and aged Charpy specimens of

various welds tested at room temperature
NUREG/CR–6428 1 4

Figure 9. Higher–magnification photomicrographs of fracture surface of unaged and aged

Charpy specimens of PWWO and PWDR welds tested at room temperature

It is well known that thermal aging of duplex SSs results in brittle fracture associated with either

cleavage of the ferrite or separation of the ferrite/austenite phase boundary.1,2,11 A brittle

fracture was not observed in the welds, most probably because of the relatively low ferrite

content and thin vermicular ferrite morphology. However, cleavage of the ferrite phase may

occur at very low temperatures. Figure 10 shows cleavage of the ferrite phase in the unaged

PWWO weld that was tested at –180°C. The amount of cleavage was slightly larger in the aged

specimen than in the unaged specimen.

3.2 Tensile Properties

Tensile tests were not conducted on the welds; tensile properties of the welds were estimated from the Charpy–impact data. The values obtained for 0.2% yield and maximum load in

each impact test are listed in Table 2, and may be used to estimate tensile properties of the

cast materials. For a Charpy specimen, the yield stress σy is estimated from the expression
1 5 NUREG/CR–6428

Figure 10.

Photomicrograph of fracture surface of

unaged Charpy specimen of PWWO weld

tested at –180°C

σy = C1 Py B/W b2 , (2a)

and the ultimate stress σu is estimated from the expression

σu = C2 Pm B/W b2 , (2b)

where Py and Pm are the yield and maximum load, respectively, W is the specimen width, B is

the specimen thickness, b is the uncracked ligament, and C1 and C2 are constants.41 The

yield and maximum loads were obtained from load–time traces of the Charpy tests. The constants C1 and C2 were determined by comparing the Charpy–impact test results with existing

tensile properties data for Type 308 and 316 weld metals. The best value of the constants was

2.2 for both C1 and C2. The estimated yield and ultimate stress for the various welds are compared with existing data for Type 308 or 316 welds in Fig. 11. Average values of yield and ultimate stress for PWWO, PWCE, PWDR, and PWMS welds are listed in Table 4. Thermal aging has

little or no effect on the tensile properties of Type 308 welds. These results are consistent

with the data from other studies.25,30–32

Table 4. Tensile yield and ultimate stress of various stainless steel welds,

estimated from Charpy–impact data

Room Temp. 290°C

Material

ID

Aging Temp.

( °C)

Aging

Time (h)

Yield Stress

(MPa)

Ultimate

Stress (MPa)

Yield Stress

(MPa)

Ultimate

Stress (MPa)

PWCE – – 4 2 5 6 4 3 3 1 5 4 3 0

4 0 0 10,000 4 4 2 6 3 5 3 2 1 4 9 0

PWWO – – 4 7 2 6 3 3 3 4 9 4 4 6

4 0 0 7 , 7 0 0 4 7 8 6 2 0 3 4 6 4 7 2

PWDR – – 4 3 7 6 0 8 2 8 9 4 2 1

4 0 0 10,000 4 4 3 5 1 9 3 0 0 4 0 9

PWMS – – 4 7 1 6 5 0 3 2 7 4 5 6
NUREG/CR–6428 1 6

2 0 0

300

400

500

600

700

0 1 0 0 200 300 400 500

308 SMAW

308 SAW

308 GTAW

316 SMAW

316 SAW

316 GTAW

Present study

(estimated)

Yield

Stress (M

P

a)

Temperature (°C)

Closed Symbols: Aged

3 0 0

400

500

600

700

800

0 1 0 0 200 300 400 500

308 SMAW

308 SAW

308 GTAW

316 SMAW

316 SAW

316 GTAW

Present study

(estimated)

Ultim

ate

Stress (M

P

a)

Temperature (°C)

Closed Symbols: Aged

Figure 11. Tensile yield and ultimate stress of

stainless steel welds. Solid lines are

the best fit to the data.

3.3 Fracture Toughness

Fracture toughness J–R curve tests were conducted at room temperature and 290°C on

the PWWO, PWCE, and PWER welds. The fracture toughness results are given in Table 5. The

effect of thermal aging on the fracture toughness J–R curves of the various materials is shown

in Figs. 12–14. The J–R curves are expressed by the power–law relation Jd = C(Δa)n per ASTM

Specifications E 813–85 and E 1152–87. The results indicate that, for all of the welds, the decrease in fracture toughness due to thermal aging is relatively small at room temperature and

290°C. The fracture toughness data are consistent with the Charpy–impact test results. The

fracture properties of SMAWs are controlled by the distribution and morphology of second–

phase particles. In these welds, failure occurs by the formation and growth of microvoids near

hard inclusions. Such processes are relatively insensitive to thermal aging. Fracture resis

tance of the PWWO weld is inferior to that of the PWCE weld because of a higher density and a
Table

5. Fracture toughness test resultsforunagedandagedausteniticstainlesssteel weldments

Test Δa Final a Deformation J b ModifiedJ b Flow 

Specimen WeldTest Temp. Comp. Opt. JIC

CJICCStress 

Number IDNo. ( °C) a/W ( mm ) ( mm ) ( k

J / m2 ) Tav ( k

J / m2 ) n ( kJ / m2 ) Tav ( kJ / m2 ) n (M

Pa) 

PWCE–02PWCE 1 2525 0.5556.066.80 482.44 1 4893.3 0.722481.9455924.6 0.763534

PWCE–04PWCE 1 2925 0.550 8.70 8.87566.0 384920.2 0.631 562.6425948.7 0.676538 

PWCE–01 PWCE 1 2329 0 0.5487.498.47363.6544648.8 0.713363.6599672.0 0.756373

PWCE–03PWCE 1 2729 0 0.548 11.10 12.26363.437 1 614.2 0.611 377.7385633.5 0.6174 0 6

PWWO–03PWWO 1 3 1 25 0.548 11.24 11.43257.3 1 93505.0 0.587258.0 2 1 0 523.7 0.617549 

PWWO–01PWWO 1 3 0 29 0 0.571 10.00 10.89242.72 0 3400.9 0.481 242.2226416.6 0.520 398 

PWWO–04PWWO 1 2829 0 0.550 13.40 13.86 189.3 1 79338.8 0.505 190.6 1 95351.7 0.5334 0 9 

PWWO–02PWWO 1 2629 0 0.562 13.73 14.05 154.62 1 9330.2 0.621 155.6235341.9 0.6454 0 9 

PWER–01 PWER 1 2429 0 0.553 10.18 10.34276.5244459.4 0.509281.3269480.3 0.541 4 0 9

aFinal crack extension: Com

p. =determined from compliance andOpt. =measured optically. bJIC

determinedwith a slope of four times the flow stress for the blunting line. cCharp

y–impact energy at the test temperature.

1 7 NUREG/CR–6428
NUREG/CR–6428 1 8

0

1500

3000

4500

0 2 4 6 8 10

As welded

Aged 10,000 h at 400°C

22500

15000

7500

0

D

eform

atio

n

J (k

J/m2

)

Crack Extension, Δ a (mm)

D

eform

atio

n

J (in.–lb/in.

2

)

Crack Extension, Δ a (in.)

0.0 0.1 0.2 0.3

(a)

0

1000

2000

3000

0 2 4 6 8 10

As welded

Aged 10,000 h at 400°C

15000

10000

5000

0

D

eform

atio

n

J (k

J/m2

)

Crack Extension, Δ a (mm)

D

eform

atio

n

J (in.–lb/in.

2

)

Crack Extension, Δ a (in.)

0.0 0.1 0.2 0.3

(b)

Figure 12. Fracture toughness J–R curve for PWCE weld at (a) room

temperature and (b) 290°C
1 9 NUREG/CR–6428

0

500

1000

1500

0 2 4 6 8 10

As welded

Aged 7,700 h at 400°C

7500

5000

2500

0

D

eform

atio

n

J (k

J/m2

)

Crack Extension, Δ a (mm)

D

eform

atio

n

J (in.–lb/in.

2

)

Crack Extension, Δ a (in.)

0.0 0.1 0.2 0.3

(a)

0

500

1000

1500

0 2 4 6 8 10

As welded

Aged 7,700 h at 400°C

7500

5000

2500

0

D

eform

atio

n

J (k

J/m2

)

Crack Extension, Δ a (mm)

D

eform

atio

n

J (in.–lb/in.

2

)

Crack Extension, Δ a (in.)

0.0 0.1 0.2 0.3

(b)

Figure 13. Fracture toughness J–R curve for PWWO weld at (a) room

temperature and (b) 290°C
NUREG/CR–6428 2 0

0

1000

2000

3000

0 2 4 6 8 10

Aged 10,000 h at 400°C

15000

10000

5000

0

D

eform

atio

n

J (k

J/m2

)

Crack Extension, Δ a (mm)

D

eform

atio

n

J (in.–lb/in.

2

)

Crack Extension, Δ a (in.)

0.0 0.1 0.2 0.3

Figure 14. Fracture toughness J–R curve for PWER weld at 290°C

larger size of inclusions. The ferrite phase has little or no effect on the fracture properties of

the welds; ferrite is resistant to local failure because of its vermicular morphology and because

it constitutes only 4–6% of the weld.

The existing fracture toughness J–R curve data from the work conducted for the U.S.

Nuclear Regulatory Commission and compiled in the Pipe Fracture (PIFRAC) Database* and from

other sources,29,30,32–34,37 are shown in Fig. 15. The PIFRAC database, consisting of the

data from Refs. 22, 26, 35, 38, and 39, was originally developed at Materials Engineering

Associates (MEA),42 and updated later by Battelle Memorial Institute.43 The results indicate

that fracture properties of SS welds are relatively insensitive to filler metal.29 However, the

welding process significantly affects fracture toughness. In general, GTAWs exhibit higher

fracture resistance than SMAWs or SAWs. The statistical differences in SAW and SMAW

fracture toughness J–R curves has also been evaluated44 and results indicate no difference

between SAW and SMAW J–R curves. At 288°C, the lower–bound J–R curve for both SAWs and

SMAWs, defined as the mean minus one standard deviation J–R curve,44 is represented by

J(kJ/m2) = 73.4 + 83.5 Δa(mm)0.643 (3)

where 73.4 kJ/m2 is the fracture toughness JIC. The lower–bound curve for SAWs and SMAWs

shows very good agreement with the data in Fig. 15. The fracture toughness data in the

technical basis document for ASME Section XI Article IWB–3640 analysis,26 are somewhat

higher than the curve given by Eq. 3. The available fracture toughness J–R curves for aged

SMAWs, SAWs, and GTAWs are shown in Fig. 16.25,28,32 In these studies, the time and

temperature of aging was sufficient to achieve saturation toughness, i.e., the minimum value

* G. Wilkowski and N. Ghadiali, “Short Crack in Piping and Piping Welds,” in Technical Data CD–ROM, Battelle

Columbus Division, Columbus, OH (May 1995).
2 1 NUREG/CR–6428

0

1000

2000

3000

0 2 4 6 8 1 0

SAW

SMAW

GTAW 15000

10000

5000

0

Deformation J (kJ/m2)

Room Temperature

Crack Extension, Δa (mm)

Deformation J (in.–lb/in.2)

Crack Extension, Δa (in.)

0.0 0.1 0.2 0.3

Open Symbols: Type 308

Closed Symbols: Type 316

(a)

0

1000

2000

3000

0 2 4 6 8 1 0

308 SAW

308 SMAW

308 GTAW

15000

10000

5000

0

Deformation J (kJ/m2)

Crack Extension, Δa (mm)

Deformation J (in.–lb/in.2)

Crack Extension, Δa (in.)

0.0 0.1 0.2 0.3

Open Symbols: Type 308

Closed Symbols: Type 316

J = 73.4 + 83.5Δ a0.643

(b)

Figure 15. Fracture toughness J–R curves for stainless steel welds at

(a) room temperature and (b) 288–427°C. Solid line represents

lower–bound curve.
NUREG/CR–6428 2 2

0

1000

2000

3000

0 2 4 6 8 1 0

SMAW

GTAW

15000

10000

5000

0

Deformation J (kJ/m2)

Room Temperature

Crack Extension, Δa (mm)

Deformation J (in.–lb/in.2)

Crack Extension, Δa (in.)

0.0 0.1 0.2 0.3

J = 40 + 83.5Δ a0.643

Open Symbols: Type 308

Closed Symbols: Type 316

(a)

0

1000

2000

3000

0 2 4 6 8 1 0

SMAW

15000

10000

5000

0

Deformation J (kJ/m2)

288–427°C

Crack Extension, Δa (mm)

Deformation J (in.–lb/in.2)

Crack Extension, Δa (in.)

0.0 0.1 0.2 0.3

J = 40 + 83.5Δ a0.643

Open Symbols: Type 308

Closed Symbols: Type 316

(b)

Figure 16. Fracture toughness J–R curves for aged stainless steel welds at

(a) room temperature and (b) 288°C. Solid line represents

lower–bound curve.
2 3 NUREG/CR–6428

0

100

200

300

400

500

600

0 100 200 300 400 500 600

308 SMAW

308 SAW

308 GTAW

316 SMAW

316 SAW

316 GTAW

Fracture Toughness JI C (kJ/m2 )

Temperature (°C)

Closed Symbols: Aged

Figure 17. Fracture toughness JIC for unaged and aged

stainless steel welds

that could be achieved after long–term aging. The JIC values for unaged and aged welds are

plotted in Fig. 17. At reactor temperatures, the fracture toughness JIC of SS welds can be as

low as 40 kJ/m2. Hence, the fracture toughness J–R curves for fully embrittled SMAWs and

SAWs can be slightly lower than that predicted by Eq. 3; a conservative estimate for aged welds

may be expressed as

J(kJ/m2) = 40 + 83.5 Δa(mm)0.643. (4)

This curve is plotted in Fig. 16. The fracture toughness J–R curves for unaged and aged SS

welds, i.e., Eqs. 3 and 4, respectively, are compared in Fig. 18 with the data for aged 316L and

CF–3 welds24,32 and the data in the technical basis document for ASME Section XI Article

IWB–3640.26 Note that the data from Ref. 26 are Jmodified rather than deformation J. The J–R

curve suggested in Ref. 26 is somewhat higher than those predicted by Eqs. 3 and 4.

4 Conclusions

Thermal–aging–induced degradation of fracture toughness and Charpy–impact properties

of several Type 304 SS pipe welds has been characterized at room temperature and 290°C.

Thermal aging of the welds resulted in moderate decreases in Charpy–impact strength and

fracture toughness at both room temperature and 290°C. For the various welds, USE decreased

by 50–80 J/cm2 (30–47 ft·lb.). The decrease in the fracture toughness J–R curve or JIC is

relatively small. Although tensile tests were not conducted on the welds, tensile proper–
NUREG/CR–6428 2 4

0

250

500

750

0 2 4 6 8 10

304 SAW (26)

316 SAW (26)

CF–3 MMAW (32)

Aged 10,000 h at 400°C

316L SAW (24)

Aged 10,000 h at 400°C

3750

2500

1250

0

Deformation J (kJ/m2)

Crack Extension, Δa (mm)

Deformation J (in.–lb/in.2)

Crack Extension, Δa (in.)

0 . 0 0.1 0.2 0.3

J = 73.4 + 83.5Δ a0.643

Unaged

J = 40.0 + 83.5Δ a0.643

Aged

288°C

J–R Curve

316 SAW (26)

Figure 18. Fracture toughness J–R curves represented by Eqs. 3 and 4

and the data for aged CF–3 and 316L welds and that in the

technical basis document for ASME Code IWB–3640 analysis

ties were estimated from the Charpy–impact data. The results indicate little or no effect of

thermal aging on tensile strength of the welds. Metallographic examination of the specimens

indicates that the fracture properties of SS welds are controlled by the distribution and morphology of second–phase particles. Differences in the fracture resistance of the welds arises

from differences in the density and size of inclusions. Failure occurs by the formation and

growth of microvoids near hard inclusions. In this study, the effect of thermal aging on fracture

properties is minimal because of the relatively low ferrite content (4–6% ferrite) and

thin vermicular ferrite morphology in the welds.

The Charpy–impact, tensile, and fracture toughness results from this study have been

compared with available data on SMAWs, SAWs, and GTAWs prepared with Types 308 or 316

SS filler metal. The data are consistent with results from other investigations. The fracture

properties of SS welds are insensitive to filler metal. The welding process has a significant effect. The large variability in the data makes it difficult to establish the effect of the welding

process on fracture properties of SS welds. In general, GTAWs exhibit higher fracture resistance

than SMAWs or SAWs, and there is no difference between SAW and SMAW J–R curves. The

Charpy–impact energy of some welds may be as low as 40 J.

The results indicate that the decrease in impact strength due to aging depends on the

ferrite content and initial impact strength of the weld. Welds with relatively high strength show

a large decrease whereas those with poor strength show minimal change. In SS welds with

poor strength, failure occurs by the formation and growth of microvoids. Such processes are

relatively insensitive to thermal aging. The existing data indicate that at reactor temperatures,

the fracture toughness JIC of thermally aged welds can be as low as 40 kJ/m2. A conservative

estimate of J–R curve for aged SS welds may be given by J = 40 + 83.5 Δa0.643.
2 5 NUREG/CR–6428

References

1. O. K. Chopra and H. M. Chung, “Effect of Low–Temperature Aging on the Mechanical

Properties of Cast Stainless Steels,” in Properties of Stainless Steels in

Elevated–Temperature Service, M. Prager, ed., MPC Vol. 26, PVP Vol. 132, ASME,

New York, pp. 79–105 (1988).

2. O. K. Chopra, “Thermal Aging of Cast Stainless Steels: Mechanisms and Predictions,” in

Fatigue, Degradation, and Fracture – 1990, W. H. Bamford, C. Becht, S. Bhandari, J. D.

Gilman, L. A. James, and M. Prager, eds., MPC Vol. 30, PVP Vol. 195, ASME, New York, pp.

193-214 (1990).

3. W. F. Michaud, P. T. Toben, W. K. Soppet, and O. K. Chopra, Tensile–Property

Characterization of Thermally Aged Cast Stainless Steels, NUREG/CR–6142, ANL–93/35

(Feb. 1994).

4. A. Trautwein and W. Gysel, "Influence of Long–Time Aging of CF–8 and CF–8M Cast Steel at

Temperatures Between 300 and 500°C on the Impact Toughness and the Structure

Properties," in Spectrum, Technische Mitteilungen aus dem+GF+Konzern, No. 5 (May

1981); also in Stainless Steel Castings, V. G. Behal and A. S. Melilli, eds., STP 756, ASTM,

Philadelphia, PA, pp. 165–189 (1982).

5. S. Bonnet, J. Bourgoin, J. Champredonde, D. Guttmann, and M. Guttmann, “Relationship

between Evolution of Mechanical Properties of Various Cast Duplex Stainless Steels and

Metallurgical and Aging Parameters: An Outline of Current EDF Programmes,” Mater. Sci.

Technol., 6 , 221–229 (1990).

6. P. H. Pumphrey and K. N. Akhurst, “Aging Kinetics of CF3 Cast Stainless Steel in

Temperature Range 300–400°C,” Mater. Sci. Technol., 6 , 211–219 (1990).

7. Y. Meyzaud, P. Ould, P. Balladon, M. Bethmont, and P. Soulat, “Tearing Resistance of Aged

Cast Austenitic Stainless Steel,” presented at Int. Conf. on Thermal Reactor Safety

(NUCSAFE 88), Oct. 1988, Avignon, France.

8. H. M. Chung and O. K. Chopra, “Kinetics and Mechanism of Thermal Aging Embrittlement of

Duplex Stainless Steels,” in Environmental Degradation of Materials in Nuclear Power

Systems–Water Reactors, G. J. Theus and J. R. Weeks, eds., The Metallurgical Society,

Warrendale, PA, pp. 359–370 (1988).

9. P. Auger, F. Danoix, A. Menand, S. Bonnet, J. Bourgoin, and M. Guttmann, “Atom Probe and

Transmission Electron Microscopy Study of Aging of Cast Duplex Stainless Steels,” Mater.

Sci. Technol., 6 , 301–313 (1990).

10. M. Vrinat, P. Cozar, and Y. Meyzaud, “Precipitated Phases in the Ferrite of Aged Cast

Duplex Stainless Steels,” Scripta Metall., 2 0, 1101–1106 (1986).
NUREG/CR–6428 2 6

11. P. Joly, R. Cozar, and A. Pineau, “Effect of Crystallographic Orientation of Austenite on the

Formation of Cleavage Cracks in Ferrite in an Aged Duplex Stainless Steel,” Scripta Metall.,

2 4, 2235–2240 (1990).

12. J. E. Brown, A. Cerezo, T. J. Godfrey, M. G. Hetherington, and G. D. W. Smith, “Quantitative

Atom Probe Analysis of Spinodal Reaction in Ferrite Phase of Duplex Stainless Steel,” Mater.

Sci. Technol., 6 , 293–300 (1990).

13. O. K. Chopra and W. J. Shack, Assessment of Thermal Embrittlement of Cast Stainless

Steels, NUREG/CR–6177, ANL–94/2 (May 1994).

14. O. K. Chopra, Estimation of Fracture Toughness of Cast Stainless Steels during Thermal

Aging in LWR Systems – Revision 1, NUREG/CR–4513 Rev. 1, ANL–93/22 (Aug. 1994).

15. O. K. Chopra, Long–Term Embrittlement of Cast Duplex Stainless Steels in LWR Systems:

Semiannual Report October 1991–March 1992, NUREG/CR–4744, Vol. 7, No. 1, ANL–92/42

(April 1993).

16. L. S. Aubrey, P. F. Wieser, W. J. Pollard, and E. A. Schoefer, “Ferrite Measurement and

Control in Cast Duplex Stainless Steel,” in Stainless Steel Castings, V. G. Behal and A. S.

Melilli, eds., ASTM STP 756, pp. 126–164 (1982).

17. P. S. Maiya and W. J. Shack, in Environmentally Assisted Cracking in Light Water Reactors:

Annual Report, October 1983–September 1984, NUREG/CR–4287, ANL–85–33, pp. 67–70

(Aug. 1985).

18. J. Y. Park, in Environmentally Assisted Cracking in Light Water Reactors: Annual Report,

October 1981–September 1982, NUREG/CR–3292, ANL–83–27, pp. 23–29 (Feb. 1983).

19. D. R. Diercks, Analysis of Cracked Core Spray Injection Line Piping from the Quad Cities

Units 1 and 2 Boiling Water Reactors, Argonne National Laboratory Report ANL–83–99

(Dec. 1983).

20. P. S. Maiya and W. J. Shack, in Environmentally Assisted Cracking in Light Water Reactors:

Annual Report, October 1983–September 1984, NUREG/CR–4287, ANL–85–33, pp. 67–70

(Aug. 1985).

21. S. Yukawa, Review and Evaluation of the Toughness of Austenitic Steels and Nickel Alloys

After Long–Term Elevated Temperature Exposures, Welding Research Council Bulletin 378,

New York (Jan. 1993).

22. R. M. Horn, H. S. Mehta, W. R. Andrews, and S. Ranganath, Evaluation of the Toughness of

Austenitic Stainless Steel Pipe Weldments, EPRI NP–4668, Electric Power Research Institute,

Palo Alto, CA (June 1986).

23. M. Strangwood and S. G. Druce, “Aging Effects in Welded Cast CF–3 Stainless Steel,” Mater.

Sci. Technol., 6 , 237–248 (1990).
2 7 NUREG/CR–6428

24. C. G. Chipperfield, “A Toughness and Defect Size Assessment of Welded Stainless Steel

Components,” Tolerance of Flaws in Pressurized Components, Inst. Mech. Eng. pp. 125–137

(1978).

25. P. Ould, P. Balladon, and Y. Mehzaud, “Fracture Toughness of Austenitic Stainless Steel

Welds,” presented at Int. Colloquim on Stainless Steels, Ecole Polytechnique, Mons, Belgium,

April 27–28, 1988.

26. J. D. Landes and D. E. McCabe, Toughness of Austenitic Stainless Steel Pipe Welds,

EPRI NP–4768, Electric Power Research Institute, Palo Alto, CA (Oct. 1986).

27. W. J. Mills, Fracture Toughness Variations for Stainless Steel Base Metal and Welds,

HEDL–TME 84–11, Hanford Engineering Development Laboratory, Richland, WA (May 1984).

28. W. J. Mills, “Fracture Toughness of Aged Stainless Steel Primary Piping and Reactor Vessel

Materials,” J. Press. Vessel Technol., 1 0 9, 440–448 (1987).

29. W. J. Mills, “Fracture Toughness of Stainless Steel Welds,” in Fracture Mechanics:

Nineteenth Symposium, T. A. Cruise, ed., ASTM STP 969, American Society for Testing and

Materials, Philadelphia, PA, pp. 330–355 (1988).

30. J. M. Vitek, S. A. David, D. J. Alexander, J. R, Keiser, and R. K. Nanstad, “Low Temperature

Aging Behavior of Type 308 Stainless Steel Weld Metal,” Acta Metall., 3 9, 503–516

(1991).

31. D. J. Alexander, K. B. Alexander, M. K. Miller, and R. K. Nanstad, “The Effect of Aging at

343°C on Type 308 Stainless Steel Weldments,” in Fatigue, Degradation, and Fracture –

1990, W. H. Bamford, C. Becht, S. Bhandari, J. D. Gilman, L. A. James, and M. Prager, eds.,

MPC Vol. 30, PVP Vol. 195, ASME, New York, pp. 187–192 (1990).

32. G. E. Hale and S. J. Garwood, “Effect of Aging on Fracture Behaviour of Cast Stainless Steel

and Weldments,” Mater. Sci. Technol., 6 , 230–236 (1990).

33. S. J. Garwood, “Fracture Toughness of Stainless Steel Weldments at Elevated

Temperatures,” in Fracture Mechanics: 15th Symposium, R. J. Sanford, ed., ASTM STP 833,

American Society for Testing and Materials, Philadelphia, PA, pp. 333–359 (1984).

34. M. G. Vassilaros, R. A. Hays, and J. P. Gudas, “Investigation of the Ductile Fracture

Properties of Type 304 Stainless Steel Plate, Welds, and 4–inch Pipe,” in Proc. 12th Water

Reactor Safety Research Information Meeting, NUREG/CP–0058, Vol. 4, U.S. Nuclear

Regulatory Commission, pp. 176–189 (1985).

35. J. P. Gudas and D. R. Anderson, “JI–R Curve Characteristics of Piping Material and Welds,” in

Proc. 9th Water Reactor Safety Research Information Meeting, Oct. 1981, U.S. Nuclear

Regulatory Commission.

36. J. R. Hawthorne and B. H. Menke, “Influence of Delta Ferrite Content and Welding Variables

on Notch Toughness of Austenitic Stainless Steel Weldments,” in Structural Materials for
NUREG/CR–6428 2 8

Service at Elevated Temperatures in Nuclear Power Generation, G. V. Smith, ed., MPC–1,

ASME, New York, pp. 351–364 (1975).

37. F. Faure, B. Houssin, and P. Balladon, “Mechanical Properties of Automatic TIG/GTA Welds

of Stainless Steel Piping in Nuclear Reactors,” in Trends in Welding Research, ASM Conf.,

Gatlinburg, May 14–18, 1989.

38. G. Wilkowski, et al., Analysis of Experiments on Stainless Steel Flux Welds,

NUREG/CR–4878, BMI–2151 (April 1987).

39. M. Nakagaki, C. Marshall, and F. Brust, Analysis of Cracks in Stainless Steel TIG Welds,

NUREG/CR–4806, BMI–2144 (Dec. 1986).

40. Mechanical Testing of Austenitic Steel Welded Joints, Joint Final Report–Vol. 2, Commission

of the European Communities, Ispra, Italy (1990).

41. W. L. Server, “Impact Three–Point Bend Testing for Notched and Precracked Specimens,” J.

Test. Eval., 6 , 29 (1978).

42. A. L. Hiser and G. M. Callahan, A User's Guide to the NRC's Piping Fracture Mechanics

Database (PIFRAC), NUREG/CR–4894 (May 1987).

43. G. M. Wilkowski, et al., Short Crcaks in Piping and Piping Welds, NUREG/CR–4599, Vols. 1 to

3, Nos. 1 and 2 (May 1991 to March 1994).

44. G. M. Wilkowski, et al., Probabilistic Pipe Fracture Evaluations for Leak–Rate–Dectection

Applications, NUREG/CR–6004 (April 1995).
2 9 NUREG/CR–6428

Appendix

J–R Curve Characterization

The J–R curve tests were performed according to ASTM Specifications E 813–85

(Standard Test Method for JIC, a Measure of Fracture Toughness) and E 1152–87 (Standard

Test Method for Determining J–R Curve). Compact–tension (CT) specimens, 25.4 mm (1 in.)

thick with 10% side grooves, were used for the tests. The design of the CT specimen is similar

to that of the specimen in ASTM Specification E 399, the notch region is modified in

accordance with E 813 and E 5112, to permit measurement of load–line displacement by axial

extensometer. The extensometer was mounted on razor blades that were screwed onto the

specimen along the load line.

Prior to testing, the specimens were fatigue–precracked at room temperature and at load

levels within the linear elastic range. The final ratio of crack length to width (a/W) after

pre–cracking was ≈0.55. The final 1–mm (≈0.04–in.) crack extension was carried out at a load

range of 13–1.3 kN (2.92–0.292 kip), i.e., during precracking, Kmax was <25 MPa·m1/2 (22.6

ksi·in.1/2). After precracking, all specimens were side–grooved to 20% of the total specimen

thickness, i.e., 10% per side, to ensure uniform crack growth during testing.

The J–R curve tests were performed on an Instron testing machine with 90 kN (20 kip)

maximum load capacity. The load and load–line displacement data were digitized with digital

voltmeters and stored on a disk for posttest analysis and correction of test data. The

single–specimen compliance procedure was used to estimate crack extension. Rotation and

modulus corrections were applied to the compliance data. Both deformation theory and

modified forms of the J integral were evaluated for each test.

After each test, the specimen was heated to 350°C to heat–tint the exposed fracture

surface. The specimen was then fractured at liquid N temperature. The initial (i.e., fatigue

precrack) and final (test) crack lengths were measured optically for both halves of the fractured

specimen. The crack lengths were determined by the 9/8 averaging technique, i.e., the two

near–surface measurements were averaged and the resultant value was averaged with the

remaining seven measurements.

The fracture toughness JIC values were determined in accordance with ASTM Specification

E 813–81 and E 813–85. For the former, JIC is defined as the intersection of the blunting line

given by J = 2σfΔa, and the linear fit of the J–vs.–Δa test data between the 0.15– and 1.5–mm

exclusion lines. The flow stress σf, is the average of the 0.2% yield stress and the ultimate

stress. The ASTM Specification E 813–85 procedure defines JIC as the intersection of the

0.2–mm offset line with the power–law fit (of the form J = CΔan) of the test data between the

exclusion lines. However, a slope of four times the flow stress (4σf) was used to define the

blunting line. The tearing modulus was also evaluated for each test. The tearing modulus is

given by T = E(dJ/da)/σf

2, where E is the Young's modulus and σf is the flow stress. The ASTM

E 813–81 value of tearing modulus is determined from the slope dJ/da of the linear fit to the

J–vs.–Δa data. For the power–law curve fits, an average value of dJ/da was calculatedA–1 to

obtain the average tearing modulus.
NUREG/CR–6428 3 0

The test data, as well as an analysis and qualification of the data, are presented in

Tables A–1 to A–27. Photographs of the fracture surface of the test specimens and

deformation and modified J–R curves for the various welds are shown in Figs. A–1 to A–27.

Data Analysis Procedures

The compliance method was used to determine crack length during the tests. The

Hudak–Saxena calibration equationA–2 was used to relate specimen load–line elastic compliance

Ci on an unloading/loading sequence with crack length ai. The compliance, i.e., slope (Δδ/ΔP) of

the load–line displacement–vs.–load record obtained during the unloading/loading sequence, is

given by

ULL = 1

(BeEeCi )

1/2

+1

(A–1)

and

ai W = 1.000196 − 4.06319(ULL ) +11.242(ULL )

2 −106.043(ULL )3

+464.335(ULL )

4 − 650.677(ULL )5, (A–2)

where Ee is the effective elastic modulus, Be is the effective specimen thickness expressed as B

– (B – BN)2/B, and W is specimen width.

Both rotation and modulus corrections are applied to the compliance data. The modulus

correctionA–2 is used to account for the uncertainties in testing, i.e., in the values of initial

crack length determined by compliance and measured optically. The effective modulus EM is

determined from

Ee = 1

CoBe

W + ao

W - ao

⎛

⎝

⎜ ⎞

⎠

⎟

1/2

f ao

W

⎛

⎝

⎞

⎠ (A–3)

and

f ao

W

⎛

⎝

⎞

⎠ = 2.163 +12.219 ao

W

⎛

⎝

⎞

⎠ - 20.065 ao

W

⎛

⎝

⎞

⎠

2

− 0.9925 ao

W

⎛

⎝

⎞

⎠

3

+20.609 ao

W

⎛

⎝

⎞

⎠

4

− 9.9314 ao

W

⎛

⎝

⎞

⎠

5

, (A–4)

where Co is initial compliance, Be is effective specimen thickness, and ao is initial physical crack

size that has been measured optically.

To account for crack–opening displacement in CT specimens, the crack size should be

corrected for rotation.A–3 The corrected compliance is calculated from
3 1 NUREG/CR–6428

θ = Sin−1 dm

2

+ D ⎛

⎝

⎞

⎠ D2 + R2 ( ) ⎡ 1/2

⎣

⎢ ⎤

⎦

⎥ − tan−1 D

R

⎛

⎝

⎞

⎠ (A–5)

and

Cc = Cm

H*

R

Sinθ − Cosθ ⎛

⎝

⎜

⎞

⎠

⎟ D

R

Sinθ − Cosθ ⎛

⎝

⎞

⎠

⎡

⎣

⎢

⎢

⎤

⎦

⎥

⎥

, (A–6)

where Cc and Cm are the corrected and measured elastic compliance at the load line, H* is the

initial half span of load points, R is the radius of rotation of the crack centerline (= (W+a)/2), a

is the updated crack length, D is one–half of the initial distance between the displacement

points (i.e., one–half of the gage length), dm is the total measured load–line displacement, and θ

is the angle of rotation of a rigid–body element about the unbroken midsection line.

The J value is calculated at any point on the load–vs.–load–line displacement record by

means of the relationship

J = Jel + Jpl , (A–7)

where Jel is the elastic component of J and Jpl is the plastic component of J. For a CT

specimen, at a point corresponding to the coordinates Pi and δi on the specimen

load–vs.–load–line displacement record, ai is (a0 + Δai), and the deformation J is given by

Jd(i) = (Ki )

2 1 − υ2 ( )

Ee

+ Jpl(i), (A–8)

where, from ASTM method E 399,

K(i) = Pi

(BBN We )

1/2

⎡

⎣

⎢

⎢

⎤

⎦

⎥

⎥

f ai

W

⎛

⎝

⎞

⎠

, (A–9)

with

f ai

W

⎛

⎝

⎞

⎠ = 2 +

ai

W

⎛

⎝

⎞

⎠

⎡

⎣

⎢ ⎤

⎦

⎥ 0.886 + 4.64 ai

W

⎛

⎝

⎞

⎠

⎡

⎣

⎢ −13.32 ai

W

⎛

⎝

⎞

⎠

2

+14.72 ai

W

⎛

⎝

⎞

⎠

3

−5.6 ai

W

⎛

⎝

⎞

⎠

4 ⎤

⎦

⎥

⎥

1 − ai

W

⎛

⎝

⎞

⎠

⎡

⎣

⎢ ⎤

⎦

⎥

3/2

(A–10)

and

Jpl(i) = Jpl(i-1) + ηi

bi

⎛

⎝

⎜ ⎞

⎠

⎟

A pl(i) − A pl(i−1)

BN

⎡

⎣

⎢ ⎤

⎦

⎥ 1 − γ i

bi

⎛

⎝

⎜ ⎞

⎠

⎟(ai − ai−1) ⎡

⎣

⎢ ⎤

⎦

⎥, (A–11)
NUREG/CR–6428 3 2

where υ is Poisson's ratio, b is the uncracked ligament, Apl is the plastic component of the area

under the load–vs.–load–line displacement record, ηis a factor that accounts for the tensile

component of the load as given by

ηi = 2 + 0.522 bi W, (A–12)

and γ, is a factor that accounts for limited crack growth as given by

γ i = 1 + 0.76 bi W. (A–13)

Modified J values (JM) are calculated from the relationship (from Ref. A–4)

JM(i) = Jd(i) + ΔJi , (A–14)

where

ΔJi = ΔJi-1 + γ i

bi

⎛

⎝

⎜ ⎞

⎠

⎟ Jpl(i)(ai − ai−1). (A–15)

According to ASTM Specification E 1152–87, the JD–R curves are valid only for crack

growth up to 10% of the initial uncracked ligament. Also, they show a dependence on

specimen size. The JM–R curves have been demonstrated to be independent of specimen size

and yield valid results for larger crack growth.

Data Qualification

The various validity criteria specified in ASTM Specification E 813–85 for JIC and in ASTM

Specification E 1152–87 for J–R curves were used to qualify the results from each test. The

various criteria include maximum values of crack extension and J–integrals; limits for initial

uncracked ligaments, effective elastic modulus, and optically measured physical crack lengths;

and spacing of J–Δa data points. The ω criterion (from Ref. A–5) was also used to ensure that a

region of J dominance exists. For the present investigation, all of the welds yielded invalid test

results; in most cases because of the shape of the final crack front. In some cases, specimen

thickness was inadequate because of the relatively high toughness of the material. The Jmax

limit for the J–vs.–Δa data was ignored in most tests to obtain a good power–law fit of the test

data.

Appendix References

A–1. A. L. Hiser, F. J. Loss, and B. H. Menke, J–R Curve Characterization of Irradiated Low Upper

Shelf Welds, NUREG/CR–3506, MEA–2028, Materials Engineering Associates, Inc., Lanham,

MD (April 1984).

A–2. A. Saxena and S. J. Hudak, Jr., "Review and Extention of Compliance Information for

Common Crack Growth Specimen,” Int. J. Fracture, 5 , 453–468 (1978).

A–3. F. J. Loss, B. H. Menke, and R. A. Gray, Jr., “Development of J–R Curve Procedures,” in

NRL–EPRI Research Program (RP 886–2), Evaluation and Prediction of Neutron
3 3 NUREG/CR–6428

Embrittlement in Reactor Pressure Vessel Materials Annual Progress Report for FY 1978,

J. R. Hawthorn, ed., NRL Report 8327, Naval Research Laboratory, Annapolis, MD (Aug.

1979).

A–4. H. A. Ernst, “Material Resistance and Instability Beyond J–Controlled Crack Growth,”

Elastic–Plastic Fracture: Second Symp., Vol. I: Inelastic Crack Analysis, ASTM STP 803,

American Society for Testing and Materials, Philadelphia (1983).

A–5. J. W. Hutchinson and P. C. Paris, “The Theory of Stability Analysis of J–Controlled Crack

Growth,” Elastic Plastic Fracture, ASTM STP 668, American Society for Testing and

Materials, Philadelphia, pp. 37–64 (1983).
NUREG/CR–6428 3 4

Table A–1. Test data for specimen PWCE–02

Test Number : 0125 Test Temp : 25 ̊C

Material Type : Weld Metal Heat Number :PWCE

Aging Temp : Unaged Aging Time : –

Thickness : 25.36 mm Net Thickness : 20.18 mm

Width : 50.78 mm Flow Stress : 534.00 MPa

Unload Jd Jm Δa Load Deflection

Number ( k J / m 2 ) ( k J / m 2 ) ( m m ) ( k N ) ( m m )

1 15.20 15.20 0.0000 23.443 0.250

2 52.28 52.31 0.0280 36.946 0.502

3 102.22 102.54 0.1172 43.820 0.755

4 157.48 158.72 0.2672 47.057 1.004

5 227.48 228.42 0.2367 48.949 1.305

6 301.95 304.11 0.3225 50.353 1.606

7 377.68 380.14 0.3385 51.045 1.911

8 454.79 456.23 0.2947 51.581 2.210

9 529.58 536.70 0.4997 52.029 2.509

1 0 603.85 613.98 0.5935 52.481 2.811

1 1 680.85 695.23 0.7086 52.830 3.116

1 2 755.23 772.60 0.7808 52.807 3.408

1 3 833.02 853.72 0.8529 52.943 3.710

1 4 907.13 935.76 1.0088 52.928 4.010

1 5 981.59 1016.74 1.1262 52.940 4.310

1 6 1056.79 1098.06 1.2275 52.844 4.610

1 7 1128.50 1180.43 1.3912 52.693 4.908

1 8 1201.74 1262.91 1.5234 52.370 5.212

1 9 1273.41 1346.72 1.6857 52.211 5.517

2 0 1352.00 1423.84 1.6673 52.127 5.809

2 1 1431.84 1540.61 2.0977 51.770 6.208

2 2 1536.75 1642.96 2.0701 51.538 6.609

2 3 1628.47 1758.04 2.3059 51.313 7.008

2 4 1720.16 1867.79 2.4772 50.992 7.411

2 5 1805.54 1978.68 2.7049 50.287 7.809

2 6 1912.16 2116.36 2.9638 49.847 8.307

2 7 2013.56 2254.97 3.2545 49.355 8.808

2 8 2134.33 2389.33 3.3538 48.396 9.309

2 9 2239.91 2528.49 3.5853 47.767 9.807

3 0 2341.12 2664.76 3.8140 47.301 10.307

3 1 2422.73 2804.41 4.1745 46.812 10.812

3 2 2553.13 2963.93 4.3445 45.997 11.411

3 3 2664.57 3129.43 4.6428 45.451 12.008

3 4 2792.24 3289.24 4.8103 44.687 12.607

3 5 2897.83 3454.39 5.1055 43.776 13.209

3 6 2992.22 3614.99 5.4187 43.160 13.808

3 7 3106.00 3803.53 5.7538 42.271 14.511

3 8 3218.54 3988.74 6.0633 41.357 15.208
3 5 NUREG/CR–6428

Table A–2. Deformation JIC and J–R curve results for specimen PWCE–02

Test Number : 0125 Test Temp : 25 ̊C

Material Type : Weld Metal Heat Number :PWCE

Aging Temp : Unaged Aging Time : –

Thickness : 25.36 mm Net Thickness : 20.18 mm

Width : 50.78 mm Flow Stress : 534.00 MPa

Modulus E : 195.06 GPa (Effective)

Modulus E : 193.10 GPa (Nominal)

Init. Crack : 28.2063 mm Init. a/ w : 0.5554 (Measured)

Final Crack : 35.0094 mm Final a/w : 0.6894 (Measured)

Final Crack : 34.2695 mm Final a/w : 0.6748 (Compliance)

Linear Fit J = B + M ( Δ a )

Intercept B : 283.992 kJ/m2 Slope M : 597.47 kJ/m3

Fit Coeff. R : 0.9900 (14 Data Points)

JIC : 394.3 kJ/m2 (2251.4 in.-lb/in.2)

Δa (JIC) : 0.185 mm (0.0073 in.)

T average : 408.7 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 893.25 kJ/m2 Exponent n : 0.7216

Fit Coeff. R : 0.9962 (14 Data Points)

JIC(0.20) : 482.4 kJ/m2 (2754.9 in.-lb/in.2)

Δa (JIC) : 0.426 mm (0.0168 in.)

T average : 414.3 (JIC at 0.20)

JIC(0.15) : 413.0 kJ/m2 (2358.4 in.-lb/in.2)

Δa (JIC) : 0.343 mm (0.0135 in.)

T average : 419.5 (JIC at 0.15)

Kj c : 559.4 MPa–m0.5

JIC Validity & Data Qualification (E 813–85)

Jmax allowed : 803.70 kJ/m2 (Jmax = boσf/15)

Data Limit : Jmax Ignored

Δa (max) allowed : 2.251 mm (at 1.5 exclusion line)

Data Limit : 1.5 Exclusion line

Data Points : Zone A = 5 Zone B = 4

Data Point Spacing : OK

Bnet or bo size : OK

dJ/da at JIC) : OK

ao Measurement : 9 Outside Limit

ao Measurement : 1 Outside Limit

af Measurement : Near-surface Outside Limit

Crack size estimate : Inadequate (by Compliance)

E Effective : OK

JIC Estimate : Invalid

J–R curve Validity & Data Qualification (E 1152–86)

Jmax allowed : 538.89 kJ/m2 (Jmax = Bnet σf/20)

Δa (max) allowed : 2.258 mm (Δa = 0.1bo)

Δa (max) allowed : 6.405 mm (ω = 5)

Data Points : Zone A = 20 Zone B = 2

Data Point Spacing : Inadequate

J-R Curve Data : Invalid
NUREG/CR–6428 3 6

Table A–3. Modified JIC and J–R curve results for specimen PWCE–02

Linear Fit J = B + M ( Δ a )

Intercept B : 255.520 kJ/m2 Slope M : 657.42 kJ/m3

Fit Coeff. R : 0.9944 (15 Data Points)

JIC : 369.1 kJ/m2 (2107.8 in.-lb/in.2)

Δa (JIC) : 0.173 mm (0.0068 in.)

T average : 449.7 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 924.64 kJ/m2 Exponent n : 0.7629

Fit Coeff. R : 0.9977 (15 Data Points)

JIC(0.20) : 481.9 kJ/m2 (2751.5 in.-lb/in.2)

Δa (JIC) : 0.426 mm (0.0168 in.)

T average : 454.7 (JIC at 0.20)

JIC(0.15) : 406.1 kJ/m2 (2319.0 in.-lb/in.2)

Δa (JIC) : 0.340 mm (0.0134 in.)

T average : 459.6 (JIC at 0.15)

Kj c : 585.5 MPa–m0.5

Figure A–1. Fracture surface of unaged weld metal PWCE tested

at 25°C
3 7 NUREG/CR–6428

0

500

1 0 0 0

1500

2000

2500

3000

0 1 2 3 4 5

D

eform

atio

n

J (in.–lb/in.

2

)

Deformation J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J =893.3(Δa) .722

J =284.00+ 597.47Δa

0.00 0.05 0.10 0.15

16000

12000

8 0 0 0

4000

0

Figure A–2. Deformation J–R curve for unaged weld metal specimen PWCE–02

tested at 25°C. Blunting, 0.2–mm offset, and 1.5–mm offset

lines are shown as dashed lines.

0

500

1 0 0 0

1500

2000

2500

3000

0 1 2 3 4 5

M

o

difie

d

J (in.–lb/in.

2

)

Modified J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J =924.6(Δa) .763

J =255.52+ 657.42Δa

0.00 0.05 0.10 0.15

16000

12000

8 0 0 0

4000

0

Figure A–3. Modified J–R curve for unaged weld metal specimen PWCE–02

tested at 25°C. Blunting, 0.2–mm offset, and 1.5–mm offset

lines are shown as dashed lines.
NUREG/CR–6428 3 8

Table A–4. Test data for specimen PWCE–04

Test Number : 0129 Test Temp : 25 ̊C

Material Type : Weld Metal Heat Number :PWCE

Aging Temp : 400 ̊C Aging Time : 10,000 h

Thickness : 25.37 mm Net Thickness : 20.29 mm

Width : 50.80 mm Flow Stress : 538.00 MPa

Unload Jd Jm Δa Load Deflection

Number ( k J / m 2 ) ( k J / m 2 ) ( m m ) ( k N ) ( m m )

1 16.29 16.28 - 0 . 1 3 0 3 26.132 0.251

2 58.75 59.01 0.1101 42.335 0.502

3 100.62 100.80 0.0805 48.905 0.703

4 150.27 150.79 0.1433 51.989 0.905

5 201.40 202.58 0.2264 53.926 1.106

6 253.46 256.21 0.3695 55.297 1.306

7 306.00 308.03 0.3180 56.009 1.507

8 362.41 364.26 0.3077 56.437 1.708

9 418.59 422.46 0.4064 57.337 1.911

1 0 471.26 477.36 0.5011 57.678 2.107

1 1 524.22 535.12 0.6809 57.882 2.307

1 2 582.23 588.55 0.5289 58.212 2.510

1 3 642.26 649.10 0.5442 58.329 2.710

1 4 700.26 705.55 0.5023 58.455 2.908

1 5 754.28 768.16 0.7150 58.539 3.112

1 6 806.09 823.63 0.7990 58.773 3.311

1 7 860.16 880.65 0.8620 58.739 3.508

1 8 913.74 940.68 0.9902 58.583 3.710

1 9 963.16 999.13 1.1594 58.668 3.908

2 0 1014.99 1058.42 1.2910 58.897 4.111

2 1 1069.51 1115.39 1.3317 58.766 4.308

2 2 1128.93 1175.39 1.3408 58.956 4.510

2 3 1190.65 1254.22 1.5925 58.914 4.759

2 4 1267.00 1322.92 1.4871 58.483 5.009

2 5 1328.22 1405.16 1.7607 58.379 5.260

2 6 1385.09 1478.41 1.9630 57.978 5.510

2 7 1459.29 1549.27 1.9239 57.701 5.761

2 8 1510.18 1630.78 2.2657 57.500 6.010

2 9 1563.64 1701.56 2.4509 57.153 6.258

3 0 1640.00 1779.10 2.4630 56.718 6.525

3 1 1701.40 1852.14 2.5761 56.527 6.759

3 2 1751.71 1929.25 2.8267 55.871 7.008

3 3 1811.93 2001.16 2.9317 55.320 7.259

3 4 1865.97 2078.21 3.1307 54.797 7.511

3 5 1919.87 2151.04 3.2885 54.298 7.759

3 6 1984.76 2223.78 3.3516 53.726 8.010

3 7 2029.35 2318.46 3.7392 53.166 8.309

3 8 2091.51 2402.24 3.9002 52.563 8.611

3 9 2143.87 2492.01 4.1688 51.562 8.908

4 0 2200.24 2578.59 4.3782 50.911 9.209

4 1 2254.35 2666.79 4.6063 50.170 9.510

4 2 2305.78 2753.14 4.8323 49.266 9.809

4 3 2354.50 2839.71 5.0698 48.875 10.108

4 4 2440.92 2954.13 5.2376 48.005 10.508

4 5 2505.67 3073.20 5.5504 47.293 10.909

4 6 2570.63 3185.61 5.8132 46.219 11.308

4 7 2629.74 3299.21 6.1042 45.356 11.707

4 8 2685.53 3411.48 6.3951 44.138 12.107

4 9 2745.00 3522.81 6.6529 43.109 12.510

5 0 2810.56 3631.55 6.8601 41.988 12.909

5 1 2851.33 3743.30 7.1901 40.930 13.307

5 2 2896.23 3878.73 7.5957 39.323 13.806

5 3 2942.63 4008.44 7.9557 37.910 14.306

5 4 2967.49 4139.43 8.3994 36.226 14.808

5 5 3015.03 4261.21 8.6994 35.079 15.307
3 9 NUREG/CR–6428

Table A–5. Deformation JIC and J–R curve results for specimen PWCE–04

Test Number : 0129 Test Temp : 25 ̊C

Material Type : Weld Metal Heat Number :PWCE

Aging Temp : 400 ̊C Aging Time : 10,000 h

Thickness : 25.37 mm Net Thickness : 20.29 mm

Width : 50.80 mm Flow Stress : 538.00 MPa

Modulus E : 207.57 GPa (Effective)

Modulus E : 193.10 GPa (Nominal)

Init. Crack : 27.9156 mm Init. a/ w : 0.5495 (Measured)

Final Crack : 36.7875 mm Final a/w : 0.7242 (Measured)

Final Crack : 36.6151 mm Final a/w : 0.7208 (Compliance)

Linear Fit J = B + M ( Δ a )

Intercept B : 371.765 kJ/m2 Slope M : 540.66 kJ/m3

Fit Coeff. R : 0.9830 (13 Data Points)

JIC : 496.5 kJ/m2 (2835.1 in.-lb/in.2)

Δa (JIC) : 0.231 mm (0.0091 in.)

T average : 387.7 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 920.22 kJ/m2 Exponent n : 0.6311

Fit Coeff. R : 0.9839 (13 Data Points)

JIC(0.20) : 566.0 kJ/m2 (3232.2 in.-lb/in.2)

Δa (JIC) : 0.463 mm (0.0182 in.)

T average : 383.8 (JIC at 0.20)

JIC(0.15) : 502.6 kJ/m2 (2870.0 in.-lb/in.2)

Δa (JIC) : 0.384 mm (0.0151 in.)

T average : 389.9 (JIC at 0.15)

Kj c : 560.8 MPa–m0.5

JIC Validity & Data Qualification (E 813–85)

Jmax allowed : 820.79 kJ/m2 (Jmax = boσf/15)

Data Limit : Jmax Ignored

Δa (max) allowed : 2.204 mm (at 1.5 exclusion line)

Data Limit : 1.5 Exclusion line

Data Points : Zone A = 3 Zone B = 4

Data Point Spacing : OK

Bnet or bo size : Inadequate

dJ/da at JIC : OK

ao Measurement : 2, 3, 7, & 8 Outside Limit

Final crack shape : OK

Crack size estimate : OK (by Compliance)

E Effective : OK

JIC Estimate : Invalid

J–R curve Validity & Data Qualification (E 1152–86)

Jmax allowed : 545.72 kJ/m2 (Jmax = Bnet σf/20)

Δa (max) allowed : 2.288 mm (Δa = 0.1bo)

Δa (max) allowed : 5.694 mm (ω = 5)

Data Points : Zone A = 23 Zone B = 4

Data Point Spacing : Inadequate

J-R Curve Data : Invalid
NUREG/CR–6428 4 0

Table A–6. Modified JIC and J–R curve results for specimen PWCE–04

Linear Fit J = B + M ( Δ a )

Intercept B : 336.028 kJ/m2 Slope M : 604.26 kJ/m3

Fit Coeff. R : 0.9862 (13 Data Points)

JIC : 467.2 kJ/m2 (2667.9 in.-lb/in.2)

Δa (JIC) : 0.217 mm (0.0085 in.)

T average : 433.3 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 948.65 kJ/m2 Exponent n : 0.6756

Fit Coeff. R : 0.9865 (13 Data Points)

JIC(0.20) : 562.6 kJ/m2 (3212.3 in.-lb/in.2)

Δa (JIC) : 0.461 mm (0.0182 in.)

T average : 424.6 (JIC at 0.20)

JIC(0.15) : 492.4 kJ/m2 (2811.4 in.-lb/in.2)

Δa (JIC) : 0.379 mm (0.0149 in.)

T average : 430.6 (JIC at 0.15)

Kj c : 585.0 MPa–m0.5

Figure A–4. Fracture surface of aged weld metal PWCE tested

at 25°C
4 1 NUREG/CR–6428

0

500

1 0 0 0

1500

2000

2500

3000

0 1 2 3 4 5

D

eform

atio

n

J (in.–lb/in.

2)

Deformation J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 920.22(Δa) .631

J =371.77+ 540.66Δa

0.00 0.05 0.10 0.15

16000

12000

8 0 0 0

4000

0

Figure A–5. Deformation J–R curve for weld metal specimen PWCE–04 aged at

400°C for 10,000 h and tested at 25°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.

0

500

1 0 0 0

1500

2000

2500

3000

0 1 2 3 4 5

M

o

difie

d

J (in.–lb/in.

2)

Modified J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 948.7(Δa) .676

J =336.03 + 604.26Δa

0.00 0.05 0.10 0.15

16000

12000

8 0 0 0

4000

0

Figure A–6. Modified J–R curve for weld metal specimen PWCE–04 aged at

400°C for 10,000 h and tested at 25°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.
NUREG/CR–6428 4 2

Table A–7. Test data for specimen PWCE–01

Test Number : 0123 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number :PWCE

Aging Temp : Unaged Aging Time : –

Thickness : 25.35 mm Net Thickness : 20.23 mm

Width : 50.81 mm Flow Stress : 373.00 MPa

Unload Jd Jm Δa Load Deflection

Number ( k J / m 2 ) ( k J / m 2 ) ( m m ) ( k N ) ( m m )

1 12.83 12.81 - 0 . 1 8 0 1 20.644 0.251

2 37.25 37.52 0.1993 30.462 0.439

3 61.29 61.62 0.2326 35.392 0.603

4 87.70 87.93 0.2021 38.210 0.754

5 126.10 125.84 0.1014 40.378 0.955

6 177.86 179.53 0.3499 41.933 1.209

7 238.23 236.54 0.0504 43.008 1.508

8 322.42 328.92 0.5599 43.798 1.907

9 407.13 406.81 0.2347 44.160 2.307

1 0 490.72 502.15 0.6859 44.638 2.707

1 1 568.31 588.66 0.9751 44.736 3.106

1 2 635.35 651.68 0.8596 44.684 3.408

1 3 762.11 790.63 1.1449 44.379 4.007

1 4 816.01 857.48 1.4240 44.091 4.309

1 5 874.14 922.90 1.5692 43.745 4.608

1 6 933.05 992.24 1.7619 43.685 4.915

1 7 996.51 1057.48 1.7925 43.150 5.213

1 8 1057.56 1124.85 1.8940 42.565 5.511

1 9 1111.88 1192.11 2.0899 42.117 5.810

2 0 1157.57 1260.04 2.4092 41.654 6.114

2 1 1203.04 1323.50 2.6550 41.250 6.407

2 2 1266.45 1387.58 2.6637 40.786 6.710

2 3 1291.86 1456.96 3.2106 40.198 7.002

2 4 1357.35 1515.39 3.1271 39.708 7.309

2 5 1396.36 1586.23 3.4879 39.192 7.609

2 6 1443.52 1648.33 3.6503 38.738 7.909

2 7 1504.17 1711.50 3.6766 38.164 8.210

2 8 1567.96 1800.27 3.9228 37.593 8.609

2 9 1621.83 1886.05 4.2228 36.760 9.012

3 0 1712.17 1988.23 4.3275 36.152 9.509

3 1 1795.79 2116.11 4.6941 34.843 10.108

3 2 1883.58 2236.71 4.9499 34.106 10.707

3 3 1949.08 2381.69 5.5332 32.721 11.409

3 4 2027.78 2516.87 5.9239 31.415 12.108

3 5 2071.46 2654.72 6.5429 29.993 12.808

3 6 2149.20 2784.49 6.8670 29.065 13.511

3 7 2226.28 2917.01 7.1945 28.289 14.207

3 8 2306.57 3049.09 7.4851 27.281 14.911
4 3 NUREG/CR–6428

Table A–8. Deformation JIC and J–R curve results for specimen PWCE–01

Test Number : 0123 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number :PWCE

Aging Temp : Unaged Aging Time : –

Thickness : 25.35 mm Net Thickness : 20.23 mm

Width : 50.81 mm Flow Stress : 373.00 MPa

Modulus E : 175.41 GPa (Effective)

Modulus E : 180.00 GPa (Nominal)

Init. Crack : 27.8406 mm Init. a/ w : 0.5479 (Measured)

Final Crack : 36.3125 mm Final a/w : 0.7147 (Measured)

Final Crack : 35.3257 mm Final a/w : 0.6953 (Compliance)

Linear Fit J = B + M ( Δ a )

Intercept B : 213.964 kJ/m2 Slope M : 430.09 kJ/m3

Fit Coeff. R : 0.9833 (10 Data Points)

JIC : 300.6 kJ/m2 (1716.6 in.-lb/in.2)

Δa (JIC) : 0.201 mm (0.0079 in.)

T average : 542.3 (JIC at 0.15)

Power Fit Law J = C(Δa)n

Coeff. C : 648.82 kJ/m2 Exponent n : 0.7127

Fit Coeff. R : 0.9783 (10 Data Points)

JIC(0.20) : 363.6 kJ/m2 (2076.1 in.-lb/in.2)

Δa (JIC) : 0.444 mm (0.0175 in.)

T average : 543.7 (JIC at 0.20)

JIC(0.15) : 313.2 kJ/m2 (1788.5 in.-lb/in.2)

Δa (JIC) : 0.360 mm (0.0142 in.)

T average : 550.7 (JIC at 0.15)

Kj c : 452.8 MPa–m0.5

JIC Validity & Data Qualification (E813-85)

Jmax allowed : 571.17 kJ/m2 (Jmax = boσf/15)

Data Limit : Jmax Ignored

Δa (max) allowed : 2.283 mm (at 1.5 exclusion line)

Data Limit : 1.5 Exclusion line

Data Points : Zone A = 2 Zone B = 4

Data Point Spacing : OK

Bnet or bo size : Inadequate

dJ/da at JIC : OK

af Measurement : Near-surface Outside Limit

Initial crack shape : OK

Crack size estimate : Inadequate (by Compliance)

E Effective : OK

JIC Estimate : Invalid

J–R curve Validity & Data Qualification (E 1152–86)

Jmax allowed : 377.21 kJ/m2 (Jmax = bnet σf/20)

Δa (max) allowed : 2.297 mm (Δa = 0.1bo)

Δa (max) allowed : 6.339 mm (ω = 5)

Data Points : Zone A = 15 Zone B = 3

Data Point Spacing : Inadequate

J-R Curve Data : Invalid
NUREG/CR–6428 4 4

Table A–9. Modified JIC and J–R curve results for specimen PWCE–01

Linear Fit J = B + M ( Δ a )

Intercept B : 187.921 kJ/m2 Slope M : 479.05 kJ/m3

Fit Coeff. R : 0.9864 (10 Data Points)

JIC : 276.8 kJ/m2 (1580.5 in.-lb/in.2)

Δa (JIC) : 0.186 mm (0.0073 in.)

T average : 604.0 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 671.99 kJ/m2 Exponent n : 0.7558

Fit Coeff. R : 0.9816 (10 Data Points)

JIC(0.20) : 363.6 kJ/m2 (2076.2 in.-lb/in.2)

Δa (JIC) : 0.444 mm (0.0175 in.)

T average : 599.2 (JIC at 0.20)

JIC(0.15) : 308.2 kJ/m2 (1760.0 in.-lb/in.2)

Δa (JIC) : 0.357 mm (0.0140 in.)

T average : 605.8 (JIC at 0.15)

Kj c : 475.1 MPa–m0.5

Figure A–7. Fracture surface of unaged weld metal PWCE tested

at 290°C
4 5 NUREG/CR–6428

0

500

1 0 0 0

1500

2000

2500

3000

0 1 2 3 4 5

D

eform

atio

n

J (in.–lb/in.

2

)

Deformation J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 648.8(Δa) .713

J =213.96 + 430.09Δa

0.00 0.05 0.10 0.15

16000

12000

8 0 0 0

4000

0

Figure A–8. Deformation J–R curve for unaged weld metal specimen PWCE–01

tested at 290°C. Blunting, 0.2–mm offset, and 1.5–mm offset

lines are shown as dashed lines.

0

500

1 0 0 0

1500

2000

2500

3000

0 1 2 3 4 5

M

o

difie

d

J (in.–lb/in.

2

)

Modified J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 672.0(Δa) .756

J =187.92 + 479.05Δa

0.00 0.05 0.10 0.15

16000

12000

8 0 0 0

4000

0

Figure A–9. Modified J–R curve for unaged weld metal specimen PWCE–01

tested at 290°C. Blunting, 0.2–mm offset, and 1.5–mm offset

lines are shown as dashed lines.
NUREG/CR–6428 4 6

Table A–10. Test data for specimen PWCE–03

Test Number : 0127 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number :PWCE

Aging Temp : 400 ̊C Aging Time : 10,000 h

Thickness : 25.35 mm Net Thickness : 20.26 mm

Width : 50.82 mm Flow Stress : 406.00 MPa

Unload Jd Jm Δa Load Deflection

Number ( k J / m 2 ) ( k J / m 2 ) ( m m ) ( k N ) ( m m )

1 13.29 13.26 - 0 . 2 9 5 9 21.718 0.252

2 48.82 49.04 - 0 . 0 5 9 4 34.743 0.503

3 92.42 92.59 - 0 . 0 7 3 8 40.085 0.755

4 142.70 143.64 0.0613 42.514 1.006

5 203.93 204.99 0.0748 44.024 1.305

6 268.19 270.91 0.2063 44.840 1.606

7 340.56 346.12 0.3738 45.440 1.946

8 384.47 392.79 0.5157 45.613 2.157

9 418.08 427.09 0.5480 45.984 2.315

1 0 461.11 470.04 0.5447 45.862 2.505

1 1 526.21 541.32 0.7650 45.508 2.809

1 2 586.62 609.83 1.0197 45.358 3.112

1 3 649.24 675.58 1.1072 45.006 3.410

1 4 715.39 743.40 1.1491 44.861 3.711

1 5 769.56 814.16 1.5298 44.556 4.008

1 6 831.39 878.96 1.5925 43.992 4.312

1 7 878.66 951.43 2.0852 43.519 4.612

1 8 938.35 1013.63 2.1308 42.737 4.916

1 9 987.24 1082.53 2.4709 42.248 5.208

2 0 1035.47 1148.47 2.7541 41.333 5.510

2 1 1094.81 1211.85 2.8147 40.599 5.810

2 2 1131.50 1282.96 3.3051 39.741 6.114

2 3 1187.67 1340.28 3.3208 38.887 6.410

2 4 1215.85 1410.90 3.8681 37.802 6.712

2 5 1254.21 1469.43 4.1176 37.194 7.011

2 6 1305.12 1555.82 4.5313 36.101 7.412

2 7 1356.82 1635.95 4.8448 34.645 7.807

2 8 1398.49 1719.30 5.2817 33.541 8.212

2 9 1448.15 1795.89 5.5504 32.323 8.609

3 0 1488.61 1875.12 5.9200 31.525 9.006

3 1 1528.97 1952.44 6.2572 30.453 9.408

3 2 1554.22 2028.49 6.7030 29.254 9.806

3 3 1584.47 2101.34 7.0628 28.037 10.208

3 4 1614.20 2174.19 7.4134 26.958 10.609

3 5 1641.89 2245.24 7.7533 25.676 11.010

3 6 1668.64 2331.92 8.2042 24.637 11.503

3 7 1684.56 2422.65 8.7445 23.133 12.038

3 8 1692.95 2497.17 9.2065 21.699 12.506

3 9 1696.54 2576.25 9.7165 20.460 13.010

4 0 1722.21 2650.89 10.0356 19.644 13.510

4 1 1736.13 2727.87 10.4324 18.589 14.007

4 2 1752.21 2801.71 10.7837 17.719 14.510

4 3 1771.22 2873.68 11.0952 16.820 15.008
4 7 NUREG/CR–6428

Table A–11. Deformation JIC and J–R curve results for specimen PWCE–03

Test Number : 0127 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number :PWCE

Aging Temp : 400 ̊C Aging Time : 10,000 h

Thickness : 25.35 mm Net Thickness : 20.26 mm

Width : 50.82 mm Flow Stress : 406.00 MPa

Modulus E : 173.53 GPa (Effective)

Modulus E : 180.00 GPa (Nominal)

Init. Crack : 27.8656 mm Init. a/ w : 0.5483 (Measured)

Final Crack : 40.1281 mm Final a/w : 0.7896 (Measured)

Final Crack : 38.9608 mm Final a/w : 0.7667 (Compliance)

Linear Fit J = B + M ( Δ a )

Intercept B : 224.977 kJ/m2 Slope M : 378.19 kJ/m3

Fit Coeff. R : 0.9815 (9 Data Points)

JIC : 293.3 kJ/m2 (1674.6 in.-lb/in.2)

Δa (JIC) : 0.181 mm (0.0071 in.)

T average : 398.1 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 614.21 kJ/m2 Exponent n : 0.6113

Fit Coeff. R : 0.9824 (9 Data Points)

JIC(0.20) : 363.4 kJ/m2 (2075.1 in.-lb/in.2)

Δa (JIC) : 0.424 mm (0.0167 in.)

T average : 371.4 (JIC at 0.20)

JIC(0.15) : 322.5 kJ/m2 (1841.6 in.-lb/in.2)

Δa (JIC) : 0.349 mm (0.0137 in.)

T average : 377.7 (JIC at 0.15)

Kj c : 409.2 MPa–m0.5

JIC Validity & Data Qualification (E 813–85)

Jmax allowed : 621.24 kJ/m2 (Jmax = boσf/15)

Data Limit : Jmax Ignored

Δa (max) allowed : 2.094 mm (at 1.5 exclusion line)

Data Limit : 1.5 Exclusion line

Data Points : Zone A = 4 Zone B = 2

Data Point Spacing : OK

Bnet or bo size : OK

dJ/da at JIC) : OK

af Measurement : Near-surface Outside Limit

Initial crack shape : OK

Crack size estimate : Inadequate (by Compliance)

E Effective : OK

JIC Estimate : Invalid

J–R curve Validity & Data Qualification (E 1152–86)

Jmax allowed : 411.26 kJ/m2 (Jmax = Bnet σf/20)

Δa (max) allowed : 2.295 mm (Δa = 0.1bo)

Δa (max) allowed : 5.536 mm (ω = 5)

Data Points : Zone A = 11 Zone B = 4

Data Point Spacing : Inadequate

J-R Curve Data : Invalid
NUREG/CR–6428 4 8

Table A–12. Modified JIC and J–R curve results for specimen PWCE–03

Linear Fit J = B + M ( Δ a )

Intercept B : 255.972 kJ/m2 Slope M : 363.36 kJ/m3

Fit Coeff. R : 0.9778 (10 Data Points)

JIC : 329.8 kJ/m2 (1882.9 in.-lb/in.2)

Δa (JIC) : 0.203 mm (0.0080 in.)

T average : 382.5 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 633.49 kJ/m2 Exponent n : 0.6172

Fit Coeff. R : 0.9864 (10 Data Points)

JIC(0.20) : 377.7 kJ/m2 (2156.5 in.-lb/in.2)

Δa (JIC) : 0.433 mm (0.0170 in.)

T average : 384.9 (JIC at 0.20)

JIC(0.15) : 335.1 kJ/m2 (1913.3 in.-lb/in.2)

Δa (JIC) : 0.356 mm (0.0140 in.)

T average : 391.4 (JIC at 0.15)

Kj c : 418.1 MPa–m0.5

Figure A–10. Fracture surface of aged weld metal PWCE tested

at 290°C
4 9 NUREG/CR–6428

0

500

1 0 0 0

1500

2000

2500

3000

0 1 2 3 4 5

D

eform

atio

n

J (in.–lb/in.

2)

Deformation J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 614.2(Δa) .611

J =224.98+ 378.19Δa

0.00 0.05 0.10 0.15

16000

12000

8 0 0 0

4000

0

Figure A–11. Deformation J–R curve for weld metal specimen PWCE–03 aged

at 400°C for 10,000 h and tested at 290°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.

0

500

1 0 0 0

1500

2000

2500

3000

0 1 2 3 4 5

M

o

difie

d

J (in.–lb/in.

2

)

Modified J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 633.5(Δa) .617

J =255.97+ 363.36Δa

0.00 0.05 0.10 0.15

16000

12000

8 0 0 0

4000

0

Figure A–12. Modified J–R curve for weld metal specimen PWCE–03 aged at

400°C for 10,000 h and tested at 290°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.
NUREG/CR–6428 5 0

Table A–13. Test data for specimen PWWO–03

Test Number : 0131 Test Temp : 25°C

Material Type : Weld Metal Heat Number : PWWO

Aging Temp : 400°C Aging Time : 7,700 h

Thickness : 22.84 mm Net Thickness : 18.24 mm

Width : 50.76 mm Flow Stress : 549.00 MPa

Unload Jd Jm Δa Load Deflection

Number ( k J / m 2 ) ( k J / m 2 ) ( m m ) ( k N ) ( m m )

1 14.72 14.71 - 0 . 1 3 2 7 22.208 0.251

2 54.82 54.89 - 0 . 0 5 0 6 37.282 0.501

3 121.93 122.42 0.0628 45.593 0.804

4 197.25 199.04 0.2348 48.740 1.105

5 248.49 251.71 0.3722 49.830 1.307

6 301.06 304.73 0.4053 50.334 1.508

7 355.13 361.66 0.5785 50.803 1.708

8 408.54 414.43 0.5465 50.841 1.909

9 462.44 474.26 0.8048 50.723 2.109

1 0 511.68 528.21 0.9859 50.696 2.308

1 1 562.26 583.59 1.1511 50.674 2.508

1 2 611.13 641.88 1.4423 49.896 2.710

1 3 656.37 697.14 1.7259 49.328 2.911

1 4 704.03 749.75 1.8546 48.782 3.109

1 5 750.58 807.86 2.1310 48.012 3.310

1 6 794.30 860.69 2.3343 47.476 3.508

1 7 837.91 916.55 2.5895 46.807 3.709

1 8 881.75 970.78 2.7923 45.981 3.912

1 9 922.61 1024.84 3.0348 44.773 4.111

2 0 960.36 1076.86 3.2832 44.133 4.307

2 1 996.69 1130.87 3.5756 43.191 4.510

2 2 1038.55 1196.72 3.9496 42.042 4.759

2 3 1078.32 1259.91 4.2944 40.692 5.009

2 4 1118.11 1322.82 4.6170 39.197 5.260

2 5 1155.41 1383.87 4.9324 38.266 5.507

2 6 1188.08 1446.55 5.3128 36.947 5.759

2 7 1217.23 1504.98 5.6683 35.671 6.007

2 8 1250.15 1577.64 6.1262 33.694 6.308

2 9 1276.82 1644.22 6.5668 32.460 6.606

3 0 1308.24 1710.28 6.9322 31.030 6.909

3 1 1336.65 1775.83 7.3079 29.969 7.207

3 2 1361.38 1839.87 7.6895 28.553 7.506

3 3 1381.79 1902.79 8.0875 27.549 7.806

3 4 1415.11 1962.18 8.3221 26.465 8.107

3 5 1441.41 2049.61 8.8452 24.941 8.508

3 6 1461.70 2123.18 9.2825 23.576 8.898

3 7 1485.33 2200.96 9.7080 22.275 9.307

3 8 1512.30 2272.98 10.0476 21.246 9.704

3 9 1536.51 2347.13 10.4091 20.376 10.108

4 0 1565.06 2437.82 10.8374 19.166 10.606
5 1 NUREG/CR–6428

Table A–14. Deformation JIC and J–R curve results for specimen PWWO–03

Test Number : 0131 Test Temp : 25°C

Material Type : Weld Metal Heat Number : PWWO

Aging Temp : 400°C Aging Time : 7,700 h

Thickness : 22.84 mm Net Thickness : 18.24 mm

Width : 50.76 mm Flow Stress : 549.00 MPa

Modulus E : 195.44 GPa (Effective)

Modulus E : 193.10 GPa (Nominal)

Init. Crack : 27.8219 mm Init. a/ w : 0.5481 (Measured)

Final Crack : 39.2563 mm Final a/w : 0.7734 (Measured)

Final Crack : 39.0582 mm Final a/w : 0.7695 (Compliance)

Linear Fit J = B + M ( Δ a )

Intercept B : 203.177 kJ/m2 Slope M : 285.61 kJ/m3

Fit Coeff. R : 0.9654 (9 Data Points)

JIC : 233.6 kJ/m2 (1333.6 in–lb/in2)

Δa (JIC) : 0.106 mm (0.0042 in.)

T average : 185.2 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 504.96 kJ/m2 Exponent n : 0.5871

Fit Coeff. R : 0.9741 (9 Data Points)

JIC(0.20) : 257.3 kJ/m2 (1469.4 in–lb/in2)

Δa (JIC) : 0.317 mm (0.0125 in.)

T average : 193.2 (JIC at 0.20)

JIC(0.15) : 225.1 kJ/m2 (1285.2 in–lb/in2)

Δa (JIC) : 0.252 mm (0.0099 in.)

T average : 196.9 (JIC at 0.15)

Kj c : 375.0 MPa–m0.5

JIC Validity & Data Qualification (E 813–85)

Jmax allowed : 839.50 kJ/m2 (Jmax = boσf/15)

Data Limit : Jmax Ignored

Δa (max) allowed : 1.828 mm (at 1.5 exclusion line)

Data Limit : 1.5 Exclusion line

Data Points : Zone A = 4 Zone B = 2

Data point spacing : OK

Bnet and bo size : OK

dJ/da at JIC : OK

af Measurement : Near-surface outside limit

Initial crack shape : OK

Crack size estimate : OK (by Compliance)

E Effective : OK

JIC Estimate : Invalid

J–R curve Validity & Data Qualification (E 1152–86)

Jmax allowed : 500.61 kJ/m2 (Jmax = Bnet σf/20)

Δa (max) allowed : 2.294 mm (Δa = 0.1bo)

Δa (max) allowed : 5.334 mm (ω = 5)

Data Points : Zone A = 4 Zone B = 9

Data point spacing : OK

J-R Curve Data : Invalid
NUREG/CR–6428 5 2

Table A–15. Modified JIC and J–R curve results for specimen PWWO–03

Linear Fit J = B + M(Δa)

Intercept B : 194.312 kJ/m2 Slope M : 313.11 kJ/m3

Fit Coeff. R : 0.9728 (9 Data Points)

JIC : 226.6 kJ/m2 (1294.1 in–lb/in2)

Δa (JIC) : 0.103 mm (0.0041 in.)

T average : 203.0 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 523.69 kJ/m2 Exponent n : 0.6171

Fit Coeff. R : 0.9785 (9 Data Points)

JIC(0.20) : 258.0 kJ/m2 (1473.0 in–lb/in2)

Δa (JIC) : 0.317 mm (0.0125 in.)

T average : 209.7 (JIC at 0.20)

JIC(0.15) : 223.6 kJ/m2 (1276.8 in–lb/in2)

Δa (JIC) : 0.252 mm (0.0099 in.)

T average : 213.4 (JIC at 0.15)

Kj c : 386.7 MPa–m0.5

Figure A–13. Fracture surface of aged weld metal PWWO tested

at 25°C
5 3 NUREG/CR–6428

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

D

eform

atio

n

J (in.–lb/in.

2)

Deformation J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J =505.0(Δa) .587

J =203.18+ 285.61Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–14. Deformation J–R curve for weld metal specimen PWWO–03 aged

at 400°C for 7,700 h and tested at 25°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

M

o

difie

d

J (in.–lb/in.

2)

Modified J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J =523.7(Δa) .617

J =194.319+ 313.11Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–15. Modified J–R curve for weld metal specimen PWWO–03 aged at

400°C for 7,700 h and tested at 25°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.
NUREG/CR–6428 5 4

Table A–16. Test data for specimen PWWO–01

Test Number : 0130 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number : PWWO

Aging Temp : Unaged Aging Time : –

Thickness : 22.80 mm Net Thickness : 18.25 mm

Width : 50.77 mm Flow Stress : 398.00 MPa

Unload Jd Jm Δa Load Deflection

Number ( k J / m 2 ) ( k J / m 2 ) ( m m ) ( k N ) ( m m )

1 11.31 11.31 - 0 . 1 3 9 5 16.399 0.252

2 42.48 42.71 0.1499 27.040 0.503

3 72.94 72.92 0.0260 31.755 0.704

4 111.34 111.56 0.0861 34.229 0.905

5 150.67 151.20 0.1372 35.577 1.107

6 190.78 192.75 0.3069 36.325 1.307

7 230.55 232.69 0.3223 36.468 1.508

8 271.78 273.85 0.3170 36.555 1.707

9 311.93 318.20 0.5812 36.638 1.906

1 0 350.21 359.05 0.7222 36.527 2.109

1 1 387.03 402.51 1.0406 35.650 2.309

1 2 422.93 441.00 1.1521 35.176 2.507

1 3 459.81 481.65 1.2985 34.566 2.704

1 4 495.21 524.90 1.5760 34.166 2.910

1 5 530.23 562.72 1.6671 33.686 3.108

1 6 563.11 605.09 1.9535 33.057 3.308

1 7 592.19 641.79 2.1692 32.554 3.498

1 8 634.02 693.63 2.4292 31.791 3.758

1 9 671.71 741.77 2.6807 30.656 4.008

2 0 706.29 789.59 2.9788 29.938 4.257

2 1 732.25 836.18 3.4159 28.299 4.502

2 2 762.66 880.74 3.6990 27.370 4.760

2 3 779.00 925.36 4.2401 26.399 5.002

2 4 801.04 966.62 4.5902 25.058 5.258

2 5 822.81 1009.16 4.9525 24.656 5.509

2 6 855.50 1048.02 5.0550 23.789 5.757

2 7 872.31 1091.38 5.4786 23.123 5.998

2 8 909.74 1138.25 5.6214 22.331 6.305

2 9 933.26 1189.65 6.0237 21.622 6.606

3 0 961.38 1235.25 6.2647 20.803 6.909

3 1 970.18 1282.16 6.7711 19.680 7.203

3 2 983.84 1324.77 7.1424 18.816 7.506

3 3 1000.88 1367.54 7.4605 18.161 7.804

3 4 1018.10 1410.95 7.7727 17.396 8.108

3 5 1025.69 1468.22 8.3404 16.255 8.504

3 6 1043.64 1519.40 8.7048 15.529 8.905

3 7 1069.02 1571.89 8.9892 14.939 9.304

3 8 1080.77 1625.23 9.4086 14.152 9.701

3 9 1104.44 1673.77 9.6496 13.552 10.100

4 0 1117.58 1724.96 10.0044 12.873 10.501
5 5 NUREG/CR–6428

Table A–17. Deformation JIC and J–R curve results for specimen PWWO–01

Test Number : 0130 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number : PWWO

Aging Temp : Unaged Aging Time : –

Thickness : 22.80 mm Net Thickness : 18.25 mm

Width : 50.77 mm Flow Stress : 398.00 MPa

Modulus E : 167.43 GPa (Effective)

Modulus E : 180.00 GPa (Nominal)

Init. Crack : 29.0063 mm Init. a/ w : 0.5714 (Measured)

Final Crack : 39.8969 mm Final a/w : 0.7859 (Measured)

Final Crack : 39.0107 mm Final a/w : 0.7684 (Compliance)

Linear Fit J = B + M ( Δ a )

Intercept B : 202.069 kJ/m2 Slope M : 191.96 kJ/m3

Fit Coeff. R : 0.9927 (7 Data Points)

JIC : 229.8 kJ/m2 (1312.1 in.-lb/in.2)

Δa (JIC) : 0.144 mm (0.0057 in.)

T average : 202.9 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 400.91 kJ/m2 Exponent n : 0.4812

Fit Coeff. R : 0.9883 (7 Data Points)

JIC(0.20) : 242.7 kJ/m2 (1386.1 in.-lb/in.2)

Δa (JIC) : 0.352 mm (0.0139 in.)

T average : 202.9 (JIC at 0.20)

JIC(0.15) : 220.4 kJ/m2 (1258.6 in.-lb/in.2)

Δa (JIC) : 0.288 mm (0.0114 in.)

T average : 207.7 (JIC at 0.15)

Kj c : 299.9 MPa–m0.5

JIC Validity & Data Qualification (E 813–85)

Jmax allowed : 577.39 kJ/m2 (Jmax = boσf/ 1 5 )

Data Limit : Jmax Ignored

Δa (max) allowed : 1.837 mm (at 1.5 exclusion line)

Data Limit : 1.5 Exclusion line

Data Points : Zone A = 1 Zone B = 3

Data Point Spacing : OK

Bnet and bo size : OK

dJ/da at JIC : OK

af Measurement : Near-surface Outside Limit

Initial crack shape : OK

Crack size estimate : Inadequate (by Compliance)

E Effective : OK

JIC Estimate : Invalid

J–R curve Validity & Data Qualification (E 1152–86)

Jmax allowed : 363.08 kJ/m2 (Jmax = Bnet σf/ 2 0 )

Δa (max) allowed : 2.176 mm (Δa = 0.1bo)

Δa (max) allowed : 4.457 mm (ω = 5)

Data Points : Zone A = 7 Zone B = 9

Data Point Spacing : OK

J-R Curve Data : Invalid
NUREG/CR–6428 5 6

Table A–18. Modified JIC and J–R curve results for specimen PWWO–01

Linear Fit J = B + M ( Δ a )

Intercept B : 193.262 kJ/m2 Slope M : 216.13 kJ/m3

Fit Coeff. R : 0.9939 (7 Data Points)

JIC : 223.6 kJ/m2 (1276.9 in.-lb/in.2)

Δa (JIC) : 0.140 mm (0.0055 in.)

T average : 228.5 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 416.63 kJ/m2 Exponent n : 0.5196

Fit Coeff. R : 0.9896 (7 Data Points)

JIC(0.20) : 242.2 kJ/m2 (1383.3 in.-lb/in.2)

Δa (JIC) : 0.352 mm (0.0139 in.)

T average : 226.4 (JIC at 0.20)

JIC(0.15) : 217.7 kJ/m2 (1243.2 in.-lb/in.2)

Δa (JIC) : 0.287 mm (0.0113 in.)

T average : 231.4 (JIC at 0.15)

Kj c : 310.4 MPa–m0.5

Figure A–16. Fracture surface of unaged weld metal PWWO

tested at 290°C
5 7 NUREG/CR–6428

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

D

eform

atio

n

J (in.–lb/in.

2)

Deformation J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 400.9(Δa) .481

J =202.07+ 191.96Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–17. Deformation J–R curve for unaged weld metal specimen

PWWO–01 tested at 290°C. Blunting, 0.2–mm offset, and

1.5–mm offset lines are shown as dashed lines.

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

M

o

difie

d

J (in.–lb/in.

2

)

Modified J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 417.3(Δa) .530

J =197.84+ 211.43Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–18. Modified J–R curve for unaged weld metal specimen PWWO–01

tested at 290°C. Blunting, 0.2–mm offset, and 1.5–mm offset

lines are shown as dashed lines.
NUREG/CR–6428 5 8

Table A–19. Test data for specimen PWWO–04

Test Number : 0128 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number : PWWO

Aging Temp : 400 ̊C Aging Time : 7,700 h

Thickness : 22.85 mm Net Thickness : 18.20 mm

Width : 50.81 mm Flow Stress : 409.00 MPa

Unload Jd Jm Δa Load Deflection

Number ( k J / m 2 ) ( k J / m 2 ) ( m m ) ( k N ) ( m m )

1 13.40 13.40 - 0 . 0 4 5 6 19.223 0.251

2 47.73 47.82 0.0516 31.277 0.502

3 92.07 91.74 - 0 . 0 8 9 9 36.179 0.754

4 144.59 146.09 0.2313 38.228 1.006

5 193.78 196.10 0.3302 39.176 1.256

6 236.04 240.70 0.5459 39.512 1.459

7 287.38 294.25 0.7041 39.441 1.709

8 328.01 336.63 0.8106 39.193 1.907

9 366.71 382.05 1.1671 38.973 2.106

1 0 402.81 425.26 1.5010 38.061 2.309

1 1 435.56 468.56 1.9490 37.500 2.508

1 2 467.46 509.09 2.2816 36.304 2.707

1 3 497.52 551.59 2.7202 34.899 2.908

1 4 524.13 592.40 3.1849 33.871 3.110

1 5 549.66 630.37 3.5639 32.410 3.307

1 6 581.33 666.88 3.7014 31.862 3.506

1 7 607.64 710.43 4.1601 30.839 3.710

1 8 630.54 748.81 4.5476 29.376 3.918

1 9 644.64 784.94 5.0753 28.491 4.108

2 0 663.72 820.03 5.4390 26.850 4.314

2 1 682.90 853.66 5.7522 25.984 4.508

2 2 696.65 900.16 6.4259 24.490 4.757

2 3 716.78 938.28 6.7777 23.311 5.011

2 4 745.18 1007.55 7.5163 21.719 5.408

2 5 772.28 1068.00 8.0774 20.143 5.809

2 6 790.29 1128.74 8.7521 18.615 6.207

2 7 797.59 1184.41 9.4739 16.729 6.605

2 8 795.67 1236.86 10.2483 15.274 7.006

2 9 808.74 1299.16 10.9049 13.672 7.506

3 0 823.99 1358.76 11.4612 12.533 8.006

3 1 821.26 1417.30 12.1900 11.294 8.506

3 2 837.00 1468.40 12.5876 10.347 9.006

3 3 856.34 1522.71 12.9590 9.622 9.506

3 4 867.50 1577.34 13.3962 8.848 10.022
5 9 NUREG/CR–6428

Table A–20. Deformation JIC and J–R curve results for specimen PWWO–04

Test Number : 0128 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number : PWWO

Aging Temp : 400 ̊C Aging Time : 7,700 h

Thickness : 22.85 mm Net Thickness : 18.20 mm

Width : 50.81 mm Flow Stress : 409.00 MPa

Modulus E : 171.79 GPa (Effective)

Modulus E : 180.00 GPa (Nominal)

Init. Crack : 27.9188 mm Init. a/ w : 0.5495 (Measured)

Final Crack : 41.7750 mm Final a/w : 0.8223 (Measured)

Final Crack : 41.3150 mm Final a/w : 0.8132 (Compliance)

Linear Fit J = B + M ( Δ a )

Intercept B : 150.815 kJ/m2 Slope M : 179.85 kJ/m3

Fit Coeff. R : 0.9695 (6 Data Points)

JIC : 169.4 kJ/m2 (967.5 in.-lb/in.2)

Δa (JIC) : 0.104 mm (0.0041 in.)

T average : 184.7 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 338.84 kJ/m2 Exponent n : 0.5051

Fit Coeff. R : 0.9872 (6 Data Points)

JIC(0.20) : 189.3 kJ/m2 (1080.7 in.-lb/in.2)

Δa (JIC) : 0.316 mm (0.0124 in.)

T average : 179.3 (JIC at 0.20)

JIC(0.15) : 169.4 kJ/m2 (967.4 in.-lb/in.2)

Δa (JIC) : 0.254 mm (0.0100 in.)

T average : 183.5 (JIC at 0.15)

Kj c : 279.0 MPa–m0.5

JIC Validity & Data Qualification (E 813–85)

Jmax allowed : 624.03 kJ/m2 (Jmax = boσf/15)

Data Limit : Jmax Ignored

Δa (max) allowed : 1.777 mm (at 1.5 exclusion line)

Data Limit : 1.5 Exclusion line

Data Points : Zone A = 2 Zone B = 1

Data Point Spacing : OK

Bnet and bo size : OK

dJ/da at JIC) : OK

Initial crack shape : OK

Final crack shape : OK

Crack size estimate : Inadequate (by Compliance)

E Effective : OK

JIC Estimate : Invalid

J–R curve Validity & Data Qualification (E 1152–86)

Jmax allowed : 372.11 kJ/m2 (Jmax = Bnet σf/20)

Δa (max) allowed : 2.289 mm (Δa = 0.1bo)

Δa (max) allowed : 4.662 mm (ω = 5)

Data Points : Zone A = 3 Zone B = 7

Data Point Spacing : Inadequate

J-R Curve Data : Invalid
NUREG/CR–6428 6 0

Table A–21. Modified JIC and J–R curve results for specimen PWWO–04

Linear Fit J = B + M ( Δ a )

Intercept B : 146.094 kJ/m2 Slope M : 197.36 kJ/m3

Fit Coeff. R : 0.9763 (6 Data Points)

JIC : 166.1 kJ/m2 (948.7 in.-lb/in.2)

Δa (JIC) : 0.102 mm (0.0040 in.)

T average : 202.7 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 351.67 kJ/m2 Exponent n : 0.5325

Fit Coeff. R : 0.9897 (6 Data Points)

JIC(0.20) : 190.6 kJ/m2 (1088.3 in.-lb/in.2)

Δa (JIC) : 0.316 mm (0.0125 in.)

T average : 195.1 (JIC at 0.20)

JIC(0.15) : 169.4 kJ/m2 (967.0 in.-lb/in.2)

Δa (JIC) : 0.254 mm (0.0100 in.)

T average : 199.4 (JIC at 0.15)

Kj c : 287.1 MPa–m0.5

Figure A–19. Fracture surface of aged weld metal PWWO tested

at 290°C
6 1 NUREG/CR–6428

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

D

eform

atio

n

J (in.–lb/in.

2

)

Deformation J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 338.8(Δa) .505

J =150.82+ 179.85Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–20. Deformation J–R curve for weld metal specimen PWWO–04 aged

at 400°C for 7,700 h and tested at 290°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

M

o

difie

d

J (in.–lb/in.

2

)

Modified J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 351.7(Δa) .533

J =146.09 + 197.36Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–21. Modified J–R curve for weld metal specimen PWWO–04 aged at

400°C for 7,700 h and tested at 290°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.
NUREG/CR–6428 6 2

Table A–22. Test data for specimen PWWO–02

Test Number : 0126 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number : PWWO

Aging Temp : 400 ̊C Aging Time : 7,700 h

Thickness : 22.84 mm Net Thickness : 18.25 mm

Width : 50.75 mm Flow Stress : 409.00 MPa

Unload Jd Jm Δa Load Deflection

Number ( k J / m 2 ) ( k J / m 2 ) ( m m ) ( k N ) ( m m )

1 13.54 13.54 0.0195 18.816 0.251

2 46.86 46.92 0.0824 29.863 0.502

3 104.46 104.16 - 0 . 0 1 5 7 35.332 0.826

4 141.63 143.09 0.2938 36.521 1.006

5 190.13 192.42 0.3915 37.441 1.257

6 245.43 251.61 0.7218 37.577 1.528

7 280.46 284.68 0.5809 37.735 1.707

8 321.85 331.83 0.9298 37.440 1.904

9 358.97 373.42 1.1657 37.215 2.108

1 0 396.27 415.94 1.4102 36.676 2.308

1 1 428.64 460.78 1.9358 36.078 2.510

1 2 464.21 495.68 1.9102 35.242 2.708

1 3 502.69 541.39 2.1608 34.758 2.911

1 4 536.61 582.55 2.3914 33.899 3.113

1 5 563.10 624.27 2.8438 32.901 3.310

1 6 574.73 665.58 3.6785 31.035 3.509

1 7 599.36 694.23 3.7855 30.069 3.706

1 8 627.89 735.82 4.1106 29.032 3.910

1 9 647.42 773.49 4.5391 28.000 4.109

2 0 666.73 808.84 4.9003 27.134 4.310

2 1 676.77 845.08 5.4653 25.673 4.506

2 2 696.31 887.41 5.9308 24.324 4.761

2 3 700.25 930.89 6.7034 22.719 5.009

2 4 723.90 993.49 7.4071 20.493 5.411

2 5 733.33 1052.86 8.2530 18.355 5.807

2 6 744.51 1107.26 8.9417 16.557 6.213

2 7 750.04 1158.83 9.6365 15.031 6.606

2 8 763.97 1207.24 10.1289 13.918 7.005

2 9 775.01 1270.72 10.8293 12.507 7.506

3 0 775.96 1326.60 11.5211 10.970 8.005

3 1 779.86 1378.73 12.0967 9.975 8.507

3 2 786.84 1429.87 12.5959 9.114 9.014

3 3 792.04 1478.72 13.0649 8.398 9.510

3 4 776.02 1527.03 13.7284 7.734 10.007
6 3 NUREG/CR–6428

Table A–23. Deformation JIC and J–R curve results for specimen PWWO–02

Test Number : 0126 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number : PWWO

Aging Temp : 400 ̊C Aging Time : 7,700 h

Thickness : 22.84 mm Net Thickness : 18.25 mm

Width : 50.75 mm Flow Stress : 409.00 MPa

Modulus E : 176.10 GPa (Effective)

Modulus E : 180.00 GPa (Nominal)

Init. Crack : 28.5000 mm Init. a/ w : 0.5615 (Measured)

Final Crack : 42.5438 mm Final a/w : 0.8382 (Measured)

Final Crack : 42.2284 mm Final a/w : 0.8320 (Compliance)

Linear Fit J = B + M ( Δ a )

Intercept B : 108.016 kJ/m2 Slope M : 214.54 kJ/m3

Fit Coeff. R : 0.9604 (7 Data Points)

JIC : 124.3 kJ/m2 (709.9 in.-lb/in.2)

Δa (JIC) : 0.076 mm (0.0030 in.)

T average : 225.9 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 330.22 kJ/m2 Exponent n : 0.6207

Fit Coeff. R : 0.9690 (7 Data Points)

JIC(0.20) : 154.6 kJ/m2 (882.9 in.-lb/in.2)

Δa (JIC) : 0.295 mm (0.0116 in.)

T average : 219.3 (JIC at 0.20)

JIC(0.15) : 133.1 kJ/m2 (760.1 in.-lb/in.2)

Δa (JIC) : 0.231 mm (0.0091 in.)

T average : 223.2 (JIC at 0.15)

Kj c : 288.9 MPa–m0.5

JIC Validity & Data Qualification (E 813–85)

Jmax allowed : 606.79 kJ/m2 (Jmax = boσf/15)

Data Limit : Jmax Ignored

Δa (max) allowed : 1.790 mm (at 1.5 exclusion line)

Data Limit : 1.5 Exclusion line

Data Points : Zone A = 3 Zone B = 1

Data Point Spacing : OK

Bnet and bo size : OK

dJ/da at JIC) : OK

af Measurement : Near-surface Outside Limit

Initial crack shape : OK

Crack size estimate : Inadequate (by Compliance)

E Effective : OK

JIC Estimate : Invalid

J–R curve Validity & Data Qualification (E 1152–86)

Jmax allowed : 373.11 kJ/m2 (Jmax = Bnet σf/20)

Δa (max) allowed : 2.225 mm (Δa = 0.1bo)

Δa (max) allowed : 5.605 mm (ω = 5)

Data Points : Zone A = 2 Zone B = 10

Data Point Spacing : OK

J-R Curve Data : Invalid
NUREG/CR–6428 6 4

Table A–24. Modified JIC and J–R curve results for specimen PWWO–02

Linear Fit J = B + M ( Δ a )

Intercept B : 103.460 kJ/m2 Slope M : 230.95 kJ/m3

Fit Coeff. R : 0.9668 (7 Data Points)

JIC : 120.5 kJ/m2 (687.9 in.-lb/in.2)

Δa (JIC) : 0.074 mm (0.0029 in.)

T average : 243.1 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 341.93 kJ/m2 Exponent n : 0.6451

Fit Coeff. R : 0.9730 (7 Data Points)

JIC(0.20) : 155.6 kJ/m2 (888.6 in.-lb/in.2)

Δa (JIC) : 0.295 mm (0.0116 in.)

T average : 234.9 (JIC at 0.20)

JIC(0.15) : 133.0 kJ/m2 (759.3 in.-lb/in.2)

Δa (JIC) : 0.231 mm (0.0091 in.)

T average : 238.9 (JIC at 0.15)

Kj c : 296.9 MPa–m0.5

Figure A–22. Fracture surface of aged weld metal PWWO

tested at 290°C
6 5 NUREG/CR–6428

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

D

eform

atio

n

J (in.–lb/in.

2

)

Deformation J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 330.2(Δa) .621

J =108.02+ 214.54Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–23. Deformation J–R curve for weld metal specimen PWWO–02 aged

at 400°C for 7,700 h and tested at 290°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

M

o

difie

d

J (in.–lb/in.

2)

Modified J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 341.9(Δa) .645

J =103.46+ 230.95Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–24. Modified J–R curve for weld metal specimen PWWO–02 aged at

400°C for 7,700 h and tested at 290°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.
NUREG/CR–6428 6 6

Table A–25. Test data for specimen PWER–01

Test Number : 0124 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number :PWER

Aging Temp : 400 ̊C Aging Time : 10,000 h

Thickness : 25.38 mm Net Thickness : 20.23 mm

Width : 50.82 mm Flow Stress : 409.00 MPa

Unload Jd Jm Δa Load Deflection

Number ( k J / m 2 ) ( k J / m 2 ) ( m m ) ( k N ) ( m m )

1 12.77 12.78 0.1408 20.967 0.251

2 35.40 35.22 - 0 . 1 5 8 0 31.170 0.442

3 63.39 63.48 - 0 . 0 0 6 1 35.990 0.602

4 91.23 91.75 0.1304 38.466 0.760

5 127.66 127.64 0.0252 40.155 0.957

6 198.54 199.40 0.1229 41.692 1.306

7 279.37 283.71 0.3753 42.390 1.707

8 360.83 365.44 0.3895 42.499 2.107

9 437.53 455.32 0.9520 42.220 2.508

1 0 512.00 535.78 1.1642 41.331 2.907

1 1 583.66 622.77 1.6278 40.579 3.310

1 2 647.88 704.84 2.1016 39.436 3.706

1 3 718.76 785.96 2.3418 38.515 4.110

1 4 771.03 871.84 3.0574 37.640 4.507

1 5 841.60 945.24 3.1118 36.280 4.908

1 6 896.63 1029.82 3.6325 34.991 5.307

1 7 950.21 1106.43 4.0083 33.939 5.708

1 8 997.64 1184.50 4.4740 32.668 6.108

1 9 1048.57 1259.07 4.8094 31.402 6.512

2 0 1096.75 1332.20 5.1418 30.192 6.909

2 1 1129.40 1406.41 5.6667 29.198 7.309

2 2 1175.69 1479.02 5.9806 28.118 7.730

2 3 1198.75 1546.87 6.4910 26.822 8.108

2 4 1231.72 1613.37 6.8557 25.792 8.508

2 5 1250.47 1681.51 7.3701 24.365 8.908

2 6 1291.77 1743.02 7.5710 23.214 9.311

2 7 1322.93 1807.13 7.8847 22.092 9.707

2 8 1335.63 1869.39 8.3400 21.036 10.107

2 9 1344.44 1927.58 8.7790 19.808 10.506

3 0 1353.94 1984.58 9.1879 18.855 10.908

3 1 1375.00 2039.54 9.4697 18.038 11.308

3 2 1380.96 2095.58 9.8737 17.166 11.707

3 3 1394.53 2147.78 10.1758 16.205 12.107
6 7 NUREG/CR–6428

Table A–26. Deformation JIC and J–R curve results for specimen PWER–01

Test Number : 0124 Test Temp : 290 ̊C

Material Type : Weld Metal Heat Number :PWER

Aging Temp : 400 ̊C Aging Time : 10,000 h

Thickness : 25.38 mm Net Thickness : 20.23 mm

Width : 50.82 mm Flow Stress : 409.00 MPa

Modulus E : 178.03 GPa (Effective)

Modulus E : 180.00 GPa (Nominal)

Init. Crack : 28.1094 mm Init. a/ w : 0.5532 (Measured)

Final Crack : 38.4531 mm Final a/w : 0.7567 (Measured)

Final Crack : 38.2852 mm Final a/w : 0.7534 (Compliance)

Linear Fit J = B + M ( Δ a )

Intercept B : 197.746 kJ/m2 Slope M : 248.00 kJ/m3

Fit Coeff. R : 0.9890 (4 Data Points)

JIC : 233.1 kJ/m2 (1330.9 in.-lb/in.2)

Δa (JIC) : 0.142 mm (0.0056 in.)

T average : 263.9 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 459.43 kJ/m2 Exponent n : 0.5092

Fit Coeff. R : 0.9974 (4 Data Points)

JIC(0.20) : 276.5 kJ/m2 (1579.1 in.-lb/in.2)

Δa (JIC) : 0.369 mm (0.0145 in.)

T average : 243.8 (JIC at 0.20)

JIC(0.15) : 250.1 kJ/m2 (1427.9 in.-lb/in.2)

Δa (JIC) : 0.303 mm (0.0119 in.)

T average : 249.2 (JIC at 0.15)

Kj c : 336.2 MPa–m0.5

JIC Validity & Data Qualification (E 813–85)

Jmax allowed : 619.11 kJ/m2 (Jmax = boσf/15)

Data Limit : Jmax Ignored

Δa (max) allowed : 1.888 mm (at 1.5 exclusion line)

Data Limit : 1.5 Exclusion line

Data Points : Zone A = 1 Zone B = 1

Data Point Spacing : OK

Bnet and bo size : OK

dJ/da at JIC) : OK

af Measurement : Near-surface Outside Limit

Initial crack shape : OK

Crack size estimate : OK (by Compliance)

E Effective : OK

JIC Estimate : Invalid

J–R curve Validity & Data Qualification (E 1152–86)

Jmax allowed : 413.62 kJ/m2 (Jmax = Bnet σf/20)

Δa (max) allowed : 2.271 mm (Δa = 0.1bo)

Δa (max) allowed : 4.697 mm (ω = 5)

Data Points : Zone A = 5 Zone B = 5

Data Point Spacing : Inadequate

J-R Curve Data : Invalid
NUREG/CR–6428 6 8

Table A–27. Modified JIC and J–R curve results for specimen PWER–01

Linear Fit J = B + M ( Δ a )

Intercept B : 190.581 kJ/m2 Slope M : 275.59 kJ/m3

Fit Coeff. R : 0.9922 (4 Data Points)

JIC : 229.2 kJ/m2 (1308.7 in.-lb/in.2)

Δa (JIC) : 0.140 mm (0.0055 in.)

T average : 293.3 (JIC at 0.15)

Power–Law Fit J = C(Δa)n

Coeff. C : 480.32 kJ/m2 Exponent n : 0.5409

Fit Coeff. R : 0.9979 (4 Data Points)

JIC(0.20) : 281.3 kJ/m2 (1606.4 in.-lb/in.2)

Δa (JIC) : 0.372 mm (0.0146 in.)

T average : 269.2 (JIC at 0.20)

JIC(0.15) : 252.4 kJ/m2 (1441.0 in.-lb/in.2)

Δa (JIC) : 0.304 mm (0.0120 in.)

T average : 274.8 (JIC at 0.15)

Kj c : 348.7 MPa–m0.5

Figure A–25. Fracture surface of aged weld metal PWER tested

at 290°C
6 9 NUREG/CR–6428

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

D

eform

atio

n

J (in.–lb/in.

2)

Deformation J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 459.43(Δa) .509

J =197.75+ 248.00Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–26. Deformation J–R curve for weld metal specimen PWER–01 aged

at 400°C for 10,000 h and tested at 290°C. Blunting, 0.2–mm

offset, and 1.5–mm offset lines are shown as dashed lines.

0

250

500

750

1 0 0 0

1250

1500

0 1 2 3 4 5

M

o

difie

d

J (in.–lb/in.

2

)

Modified J (kJ/m2

)

Crack Extension, Δa (mm)

Crack Extension Δa (in.)

J = 480.3(Δa) .541

J =190.58+ 275.59Δa

0.00 0.05 0.10 0.15

8 0 0 0

6000

4000

2000

0

Figure A–27. Modified J–R curve for metal specimen PWER–01 aged at 400°C

for 10,000 h and tested at 290°C. Blunting, 0.2–mm offset,

and 1.5–mm offset lines are shown as dashed lines.
NUREG/CR–6428 7 0
7 1 NUREG/CR–6428

Distribution for NUREG/CR–6428 (ANL–95/47)

Internal:

W. F. Burke T. F. Kassner W. J. Shack

O. K. Chopra (20) C. Malefyt C. E. Till

T. M. Galvin W. F. Michaud R. W. Weeks

D. J. Gavenda (5) R. B. Poeppel TIS Files

External:

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ANL–E (2)

ANL–W

Manager, Chicago Field Office, DOE

Energy Technology Division Review Committee

H. K. Birnbaum, University of Illinois, Urbana

R. C. Buchanan, University of Cincinnati, Cincinnati, OH

S.-N. Liu, Fremont, CA

H. S. Rosenbaum, Fremont, CA

R. K. Shah, University of Kentucky, Lexington

S. Smialowska, Ohio State University, Columbus

R. E. Smith, Altran Corp., Huntersville, NC

D. Atteridge, Battelle Pacific Northwest Laboratory

W. H. Bamford, Westinghouse Electric Corp., Pittsburgh, PA

K. K. Bandyopadhyay, Brookhaven National Laboratory

J. A. Christensen, Battelle Pacific Northwest Laboratory

A. Cowan, Risley Nuclear Power Development Labs., Risley, Warrington, UK

W. H. Cullen, Materials Engineering Associates, Inc., Lanham, MD

B. J. L. Darlaston, Berkeley Nuclear Laboratories, Berkeley, Gloucestershire, UK

G. Gage, AEA Technology, Harwell Laboratory, Oxfordshire, UK

J. Gilman, Electric Power Research Inst., Palo Alto, CA

W. Gysel, Georg Fischer, Ltd., Schaffhausen, Switzerland

G. E. Hale, The Welding Institute, Abington, Cambridge, UK

P. Hedgecock, APTECH Engineering Services, Inc., Palo Alto, CA

B. Hemsworth, HM Nuclear Installations Inspectorate, London, UK

C. Hoffmann, ABB CE Nuclear Power, Windsor, CT

J. Jansky, Büro für Technische Beratung, Leonberg, Germany

C. E. Jaske, CC Technologies, Cortest, Columbus, OH

G. J. Licina, Structural Integrity Associates, San Jose, CA

T. R. Mager, Westinghouse Electric Corp., Pittsburgh, PA

H. Mehta, General Electric Co., San Jose, CA

Y. Meyzaud, Framatome, Paris La Defense, France

M. Prager, Materials Properties Council, Inc., New York, NY

D. Quiñones, Robert Cloud & Associates, Berkeley, CA

C. Y. Rieg, Electricité de France, Villeurbanne Cedex, France

V. N. Shah, EG&G Idaho, Inc., Idaho Falls, Idaho
NUREG/CR–6428 7 2

G. Slama, Framatome, Paris La Defense, France

D. M. Stevens, Lynchburg Research Center, Babcock & Wilcox Co., Lynchburg, VA

L. Taylor, Nuclear Electric plc., Chelsford Rd., Knutsford, Cheshire, UK

J. C. Van Duysen, Electricité de France, Moret–Sur–Loing, France

S. Yukawa, Boulder, CO
NRC FORM 335

(2–89)

NRCM 1102,

U. S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER

(Assigned by NRC. Add Vol., Supp., Rev.,

and Addendum Numbers, if any.)

3201, 3202 BIBLIOGRAPHIC DATA SHEET NUREG/CR–6428

(See instructions on the reverse) ANL–95/47

2. TITLE AND SUBTITLE

Effects of Thermal Aging on Fracture Toughness and Charpy–Impact Strength of

Stainless Steel Pipe Welds 3. DATE REPORT PUBLISHED

MONTH YEAR

May 1 9 9 6

4. FIN OR GRANT NUMBER

A2212

5. AUTHOR(S) 6. TYPE OF REPORT

D. J. Gavenda, W. F. Michaud, T. M. Galvin, W. F. Burke, and O. K. Chopra Technical

7. PERIOD COVERED (Inclusive Dates)

8. PERFORMING ORGANIZATION – NAME AND ADDRESS (If NRC, provide Division, Office or Region, U.S. Nuclear Regulatory Commission, and mailing address; if contractor, provide

name and mailing address.)

Argonne National Laboratory

9700 South Cass Avenue

Argonne, IL 60439

9. SPONSORING ORGANIZATION – NAME AND ADDRESS (If NRC, type “Same as above”: if contractor, provide NRC Division, Office or Region, U.S. Nuclear Regulatory Commission,

and mailing address.)

Division of Engineering

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, DC 20555

10. SUPPLEMENTARY NOTES

11. ABSTRACT (200 words or less)

The degradation of fracture toughness, tensile, and Charpy–impact properties of Type 308 stainless steel (SS) pipe welds due to

thermal aging has been characterized at room temperature and 290°C. Thermal aging of SS welds results in moderate decreases i n

Charpy–impact strength and fracture toughness. For the various welds in this study, upper–shelf energy decreased by

50–80 J/cm2. The decrease in fracture toughness J–R curve or JIC is relatively small. Thermal aging had little or no effect on

the tensile strength of the welds. Fracture properties of SS welds are controlled by the distribution and morphology of

second–phase particles. Failure occurs by the formation and growth of microvoids near hard inclusions. Such processes are

relatively insensitive to thermal aging. The ferrite phase has little or no effect on the fracture properties of the welds.

Differences in fracture resistance of the welds arise from differences in the density and size of inclusions. The

mechanical–property data from the present study are consistent with results from other investigations. The existing data have

been used to establish minimum expected fracture properties for SS welds.

12. KEY WORDS/DESCRIPTORS (List words or phrases that will assist researchers in locating this report.) 13. AVAILABILITY STATEMENT

Unlimited

14. SECURITY CLASSIFICATION

(This Page)

Unclassified

(This Report)

Unclassified

15. NUMBER OF PAGES

16. PRICE

NRC FORM 335 (2–89)