Fatigue Crack Growth in SA508-CL2 Steel in a High Temperature, High Purity Water Environment

1974 ◽  
Vol 96 (4) ◽  
pp. 255-260 ◽  
Author(s):  
T. L. Gerber ◽  
J. D. Heald ◽  
E. Kiss
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
High Purity ◽  
Room Temperature ◽  
Water Environment ◽  
Cyclic Frequency ◽  
Asme Code ◽  
Temperature Rate

Fatigue crack growth tests were conducted with 1 in. (25.4 mm) plate specimens of SA508-CL2 steel in room temperature air, 550 deg F (288 deg C) air and in a 550 deg F (288 deg C), high purity, water environment. Zero-tension load controlled tests were run at cyclic frequencies as low as 0.037 CPM. Results show that growth rates in the simulated Boiling Water Reactor (BWR) water environment are 4 to 8 times faster than growth rates observed in 550 deg F (288 deg C) air and these rates are 8 to 15 times faster than the room temperature rate. In the BWR water environment, lowering the cyclic frequency from 0.37 CPM to 0.037 CPM caused only a slight increase in the fatigue crack growth rate. All growth rates measured in these tests were below the upper bound design curve presented in Section XI of the ASME Code.

An Assessment of Low Alloy Steel EAC Corrosion Fatigue Relationships for BWR Environment

2005 ◽  
Author(s):  
Hardayal Mehta ◽  
Ron Horn
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Water Chemistry ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
Growth Rates ◽  
Ferritic Steels ◽  
Asme Code ◽  
Crack Growth Rates

The fatigue crack growth rates for ferritic steels in water environments given in A-4300 of Appendix A, Section XI, ASME Code, were developed from data obtained prior to 1980. Subsequently, updated assessments by Eason, et al. and recent laboratory test results from Seifert and Ritter demonstrated that under certain conditions, ferritic steels exposed to oxygenated water environments may be susceptible to high fatigue crack growth rates that exceed the current disposition curves. In the light of ASME adopting Code Case N-643 for PWRs, there is a need for a similar Code Case for the BWR water environments (for both the normal water chemistry and hydrogen water chemistry/NobleChem) that takes into account these findings. This could mean modification of current EAC curves in the ASME Code. A joint program of EPRI and GE was developed to address this need for updated evaluations of the corrosion fatigue. The program’s first task has been to re-assess the role of rise time, environment, alloy, heat treatment and impurity levels on the established ASME codified disposition curves/methodologies. The data was then used as a basis to assess the impact of on modified cyclic curves on the disposition approaches that are currently used to evaluate postulated flaws in the BWR reactor pressure vessel or RPV head and the feed water nozzle regions. The presentation would include a discussion of the appropriate BWR plant transients and the GE process for performing evaluations. The role of the evaluations on the establishment of inspection intervals currently determined using NUREG-0619 and the latest BWROG Report would also be presented. Finally, the relationship between cyclic load and constant load behavior in these steels are discussed in the context of the mechanisms for environmentally assisted cracking.

A Critical Review of Recent Fatigue Crack Growth Data in Relation to ASME Code Case N-809

2019 ◽  
Author(s):  
Jonathan Mann ◽  
Chris Currie ◽  
David Tice ◽  
Norman Platts
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Water Environment ◽  
Low Carbon ◽  
Growth Data ◽  
R Ratio ◽  
Asme Code ◽  
Best Fit

Abstract ASME Code Case N-809 provides Fatigue Crack Growth (FCG) expressions for austenitic stainless steels operating in a primary water environment within a Pressurised Water Reactor (PWR). The code case currently contains different expressions for nominally low-carbon (304L, 316L) and conventional (304, 316) grades. Since the original work that provided the technical basis for N-809 was completed, an increased amount of FCG data has become available through industry testing, particularly for low-carbon stainless steels. A large database is now available that contains significantly more data than the one used in the original development of the code case. The data cover a wider range of testing conditions (temperature, loading rate, and mean stress) and represent a more diverse population of material types, including multiple heats. In this paper, the N-809 laws are re-analysed in terms of these new data, with a focus on each of the environmental dependencies that are currently included in the law. In particular, alternative R-ratio expressions from the literature are shown to provide an improved description of the effect of R-ratio for nominally low-carbon materials. The statistical distribution of FCG rates and the treatment of partially retarded data are also investigated as part of the derivation of revised descriptions of best-fit and bounding FCG rates. The analysis highlights a small amount of potential non-conservatism in the current N-809 description of best-fit FCG rates at higher R-ratios. The current description of upper-bounding behaviour is shown to still be valid, however significant over-conservatism exists at lower R-ratios.

scholarly journals Fatigue-Crack Growth-Rate Studies of Low-Alloy Pressure-Vessel Steels

1968 ◽  
Vol 90 (4) ◽  
pp. 648-655 ◽  
Author(s):  
D. F. Mowbray ◽  
W. R. Andrews ◽  
A. J. Brothers
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Crack Extension ◽  
Room Temperature ◽  
Plate Thickness ◽  
Pressure Vessel Steels ◽  
Class B ◽  
Crack Growth Rates

Fatigue-crack growth rates were determined at room temperature for ASTM A302-Class B and A 508-Class 2 steels in two characteristic plate and forging directions. Tests were performed under zero-to-tension cyclic loading using both through-crack and part-through-crack plate specimens. Crack growth rates in the through-crack specimens, though affected by plate or forging directions, were found to correlate well upon the hypothesis that the crack extension per cycle is proportional to a positive power of the range of alternating stress intensity factor. In addition, the rate of crack extension through the plate thickness of the surface-crack specimens was successfully correlated with data from through-crack specimens.

Fatigue Crack Growth Rates for Ferritic Steels Under Negative R Ratio

2016 ◽  
Author(s):  
Kunio Hasegawa ◽  
Vratislav Mares ◽  
Yoshihito Yamaguchi ◽  
Yinsheng Li
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Closure ◽  
Growth Rates ◽  
Ferritic Steels ◽  
R Ratio ◽  
Asme Code ◽  
Reference Curves ◽  
Crack Growth Rates

Reference curves of fatigue crack growth rates for ferritic steels in air environment are provided by the ASME Code Section XI Appendix A. The fatigue crack growth rates under negative R ratio are given as da/dN vs. Kmax, It is generally well known that the growth rates decreases with decreasing R ratios. However, the da/dN as a function of Kmax are the same curves under R = 0, −1 and −2. In addition, the da/dN increases with decreasing R ratio for R < −2. This paper converts from da/dN vs. Kmax to da/dN vs. ΔKI, using crack closure U. It can be obtained that the growth rates da/dN as a function of ΔKI decrease with decreasing R ratio for −2 ≤ R < 0. It can be seen that the growth rate da/dN vs. ΔKI is better equation than da/dN vs. Kmax from the view point of stress ratio R. Furthermore, extending crack closure U to R = −5, it can be explained that the da/dN decreases with decreasing R ratio in the range of −5 ≤ R < 0. This tendency is consistent with the experimental data.

Reference Curve of Fatigue Crack Growth for Ferritic Steels Under Negative R Ratio Provided by ASME Code Section XI

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Kunio Hasegawa ◽  
Vratislav Mares ◽  
Yoshihito Yamaguchi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Closure ◽  
Growth Rates ◽  
Ferritic Steels ◽  
Reference Curve ◽  
R Ratio ◽  
Asme Code ◽  
Crack Growth Rates

Reference curves of fatigue crack growth rates for ferritic steels in air environment are provided by the ASME Code Section XI Appendix A. The fatigue crack growth rates under negative R ratio are given as da/dN versus Kmax. It is generally well known that the growth rates decreases with decreasing R ratios. However, the da/dN as a function of Kmax are the same curves under R = 0, −1, and −2. In addition, the da/dN increases with decreasing R ratio for R < −2. This paper converts from da/dN versus Kmax to da/dN versus ΔKI, using crack closure U. It can be obtained that the growth rates da/dN as a function of ΔKI decrease with decreasing R ratio for −2 ≤ R < 0. It can be seen that the growth rate da/dN versus ΔKI is better equation than da/dN versus Kmax from the view point of stress ratio R. Furthermore, extending crack closure U to R = −5, it can be explained that the da/dN decreases with decreasing R ratio in the range of −5 ≤ R < 0. This tendency is consistent with the experimental data.

scholarly journals Advantageous Description of Short Fatigue Crack Growth Rates in Austenitic Stainless Steels with Distinct Properties

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 475
Author(s):  
Lukáš Trávníček ◽  
Ivo Kuběna ◽  
Veronika Mazánová ◽  
Tomáš Vojtek ◽  
Jaroslav Polák ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Growth Rates ◽  
Large Scale ◽  
J Integral ◽  
Scale Yielding ◽  
Residual Fatigue ◽  
Crack Growth Rates

In this work two approaches to the description of short fatigue crack growth rate under large-scale yielding condition were comprehensively tested: (i) plastic component of the J-integral and (ii) Polák model of crack propagation. The ability to predict residual fatigue life of bodies with short initial cracks was studied for stainless steels Sanicro 25 and 304L. Despite their coarse microstructure and very different cyclic stress–strain response, the employed continuum mechanics models were found to give satisfactory results. Finite element modeling was used to determine the J-integrals and to simulate the evolution of crack front shapes, which corresponded to the real cracks observed on the fracture surfaces of the specimens. Residual fatigue lives estimated by these models were in good agreement with the number of cycles to failure of individual test specimens strained at various total strain amplitudes. Moreover, the crack growth rates of both investigated materials fell onto the same curve that was previously obtained for other steels with different properties. Such a “master curve” was achieved using the plastic part of J-integral and it has the potential of being an advantageous tool to model the fatigue crack propagation under large-scale yielding regime without a need of any additional experimental data.

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