Measuring the condition of high-temperature components after many years of service is an important part of remaining life assessment. Tests of miniature specimens have been utilized for this purpose because they require that only small samples be removed from the components, which minimizes or eliminates the need for costly repairs. Miniature-specimen techniques have been developed and validated for creep-rupture testing but not for creep-crack-growth testing. The objective of this research was to develop and validate a procedure for measuring creep-crack-growth behavior using miniature specimens. Based on a past study of Type 316 stainless steel, the single-edge-notch-tension (SENT) specimen configuration was chosen for the current work. SENT specimens were designed and prepared from both base metal and weldments of 2-1/4Cr-1Mo and 1-1/4Cr-1/2Mo steels. The base metal was ASME SA 387, Grade P22 and Grade P11 plate, respectively. The 2-1/4Cr-1Mo steel weldment was a seam-weld hot reheat steam pipe that had been in service for 106,000 hours, while the 1-1/4Cr-1/2Mo steel weldment was from a pipe that had been weld repaired after 244,200 hours of service. SENT specimens with test sections of 10×5×1.5 mm, 15×7.5×1.5 mm, and 20×10×1.5 mm were evaluated. Tests were conducted under constant weight loading or constant load-line displacement loading. Specimens were heated to 538°C using a standard laboratory furnace. Crack length was measured using the DC electric potential drop method. The test results were analyzed to produce creep-crack-growth rate da/dt as a function of the C* integral and compared with data from tests of half-size (1/2T-CT) and standard full-size (1T-CT) compact-tension specimens. For both base metals, the 1/2T-CT and three sizes of SENT specimens gave results that agreed well with those of 1T-CT specimens. For the 2-1/4Cr-1Mo steel weldments, SENT specimens produced good results. However, SENT specimens of the 1-1/4Cr-1/2Mo steel weldments exhibited cracking blunting and no creep crack growth. The reasons for the differences in behavior are discussed and guidance for application of miniature specimens to creep-crack-growth testing is presented. [S0094-4289(00)01403-1]

Issue Section:
Technical Papers
Keywords:
creep testing, crack detection, fracture mechanics, life testing, welding, structural engineering, alloy steel
Topics:
Creep, Fracture (Materials), Testing, Steel, Base metals
1.
Viswanathan
,
R.
, and
Bruemmer
,
S. M.
,
1985
, “
In-Service Degradation of Toughness of Steam Turbine Rotors
,”
ASME J. Eng. Mater. Technol.
,
107
, pp.
316
–
324
.
2.
Jaske, C. E., Smith, S, Kiefner, J. F., and Rosenfield, A. R., 1987, “Life Assessment of High Temperature Fossil Plant Components,” Proceedings of EPRI Conference on Life Extension and Assessment of Fossil Plants, EPRI CS-5208, Electric Power Research Institute, Palo Alto, CA.
3.
Jaske, C. E., 1987, Chem. Eng. Prog., Apr., pp. 37–46.
4.
McNaughton
,
W. P.
,
Richman
,
R. H.
,
Pillar
,
C. S.
, and
Perry
,
L. W.
,
1986
, “Generic Guidelines for the Life Extension of Fossil Fuel Power Plants,” Final Report on Project 2596-1, EPRI CS-4778, Electric Power Research Institute, Palo Alto, CA.
5.
Parker
,
J. D.
,
McMinn
,
A.
,
Bell
,
R. J.
,
Richman
,
R. H.
,
McNaughton
,
W. P.
,
Dimmer
,
J. P.
,
Damon
,
J. E.
,
Galpin
,
D. S.
, and
Dooley
,
R. B.
,
1990
, “Condition Assessment Guidelines for Fossil Fuel Power Plant Components,” Topical Report on Project 2596-10, EPRI GS-6724, Electric Power Research Institute, Palo Alto.
6.
Becker
,
F. L.
,
Walker
,
S. M.
, and
Viswanathan
,
R.
,
1987
, “Guidelines for the Evaluation of Seam-Welded Steam Pipes,” EPRI CS-4774, Final Report on Research Project 2596-7, Electric Power Research Institute, Palo Alto, CA.
7.
Foulds
,
J. R.
,
Viswanathan
,
R.
,
Landrum
,
J. L.
, and
Walker
,
S. M.
,
1988
, “Guidelines for the Evaluation of Seam-Welded High Energy Piping,” EPRI TR-104631, Final Report on Research Project 8046-04, 2819-24, Electric Power Research Institute, Palo Alto, CA.
8.
Saxena
,
A.
,
Han
,
J.
, and
Banerji
,
K.
,
1988
, “Creep Crack Growth in Boiler and Steam Pipe Steels,” EPRI CS-5585, Topical Report on Research Project 2253-10, Electric Power Research Institute, Palo Alto, CA.
9.
Marschall
,
C. W.
,
Jaske
,
C. E.
, and
Majumdar
,
B. S.
,
1992
, “Assessment of Seam Welded Steel Piping in Fossil Power Plants,” EPRI TR-101835 Final Report on Research Project 2596-11, Electric Power Research Institute, Palo Alto, CA.
10.
Jaske, C. E., and Viswanathan, R., 1995, “Properties of Cr-Mo Steels after Long-Term High-Temperature Service,” Service Experience, Structural Integrity, Service Accidents, and Erosion in Nuclear and Fossil Plants, PVP-Vol. 303, ASME International, New York, pp. 235–245.
11.
Askins
,
M. C.
, and
Marchant
,
K. D.
,
1988
, “Remaining-Life Estimation of Boiler Pressure Parts, Volume 2: Miniature Specimen Creep Testing,” EPRI CS-5588, Volume 2, Final Report on Research Project 2253-1, Electric Power Research Institute, Palo Alto, CA.
12.
Jaske, C. E., 1988, “Long-Term Creep-Crack-Growth Behavior of Type 316 Stainless Steel,” Fracture Mechanics: Eighteenth Symposium, ASTM STP 945, American Society for Testing and Materials, Philadelphia, pp. 867–877.
13.
Majumdar
,
B. S.
,
Jaske
,
C. E.
, and
Manahan
,
M. P.
,
1991
, “
Creep Crack Growth Characterization of Type 316 Stainless Steel Using Miniature Specimens
,”
Int. J. Fract.
,
47
, pp.
127
–
144
.
14.
Hendrix, R., Khoury, J. M., King, J. P., and Ryder, B., 1996, “Evaluation of Hot Reheat Steam Piping, Including a Test Spool Piece, at the Big Cajun II Station,” paper presented at Power-Gen’96 International, Orlando, FL, December 4–6.
15.
Jaske
,
C. E.
, and
Shademan
,
S. S.
,
1999
, “Measurement of Creep Crack Growth Using Miniature Specimens,” Report TR-111716, Electric Power Research Institute, Palo Alto, CA.
16.
Johnson
,
H. H.
,
1965
, “
Calibrating the Electric Potential Method for Studying Slow Crack Growth
,”
Mater. Res. Stand.
,
5
, pp.
442
–
445
.
17.
Jaske, C. E., 1984, “Damage Accumulation by Crack Growth Under Combined Creep and Fatigue,” Ph.D. dissertation, The Ohio State University, Columbus, OH.
18.
Jaske, C. E., 1983, “Creep-Fatigue-Crack Growth in Type 316 Stainless Steel,” Advances in Life Prediction Methods, ASME International, New York, pp. 93–103.
19.
Jaske
,
C. E.
,
1983
, “
A Crack-Tip-Zone Interaction Model for Creep-Fatigue Crack Growth
,”
Fatigue Eng. Mater. Struct.
,
6
, No.
2
, pp.
159
–
166
.
20.
Broek, D., 1978, Elementary Fracture Mechanics, Sijthoff and Noordhoff International Publishers, The Netherlands.
21.
Jaske, C. E., 1986, “Estimation of the C* Integral for Creep-Crack-Growth Test Specimens,” The Mechanism of Fracture, ASM International, Materials Park, OH, pp. 577–585.
22.
Riedel, H., and Rice, J. R., 1980, “Tensile Cracks in Creeping Solids,” Fracture Mechanics: Twelfth Conference, ASTM STP 700, American Society for Testing and Materials, Philadelphia, pp. 112–130.
23.
Liaw
,
P. K.
,
Saxena
,
A.
, and
Schaefer
,
J.
,
1989
, “
Estimating Remaining Life of Elevated-Temperature Steam Pipes—Part 1. Material Properties
,”
Eng. Fract. Mech.
,
32
, No.
5
, pp.
675
–
708
.
Copyright © 2000
 by ASME
You do not currently have access to this content.