Development of Fatigue Crack Growth Thresholds for Austenitic Stainless Steels Exposed to Air Environment for ASME Code Section XI

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Kunio Hasegawa ◽  
Saburo Usami
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Stress Ratio ◽  
Austenitic Stainless Steels ◽  
Stress Intensity Factor Range ◽  
Asme Code ◽  
American Society ◽  
Growth Experiments

Fatigue crack growth thresholds ΔKth define stress intensity factor range below which cracks will not grow. The thresholds ΔKth are useful in industries to determine durability lifetime. Although massive fatigue crack growth experiments for stainless steels in air environment had been reported, the thresholds ΔKth are not codified at the American Society of Mechanical Engineers (ASME) Code Section XI, as well as other fitness-for-service (FFS) codes and standards. Based on the investigation of a few FFS codes and review of literature survey of experimental data, the thresholds ΔKth exposed to air environment have been developed for the ASME Code Section XI. A guidance of the thresholds ΔKth for austenitic stainless steels in air at room and high temperatures can be developed as a function of stress ratio R.

Technical Basis of Fatigue Crack Growth Threshold for Stainless Steel in Air Environment for ASME Code Section XI

2017 ◽  
Author(s):  
Kunio Hasegawa ◽  
Saburo Usami
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Threshold Values ◽  
Asme Code ◽  
American Society ◽  
Growth Threshold

The fatigue crack growth threshold is an important characteristic of crack growth assessment for the integrity of structural components. However, threshold values for austenitic stainless steels in air environment are not well provided in many fitness-for-service (FFS) codes, although extensive amount of fatigue crack growth tests data has been published. This paper focuses on fatigue crack growth threshold values for austenitic stainless steel in air environment at room and high temperatures. The paper introduces the current fatigue crack growth rates provided by the ASME (American Society of Mechanical Engineers) Code Section XI and summarizes the available test data of fatigue crack growth thresholds based on the literature survey. The paper then discusses the applicability of the existing fatigue crack growth thresholds for stainless steels and proposes a new relation as a function of the stress ratio for use by the ASME Code Section XI.

Fatigue Crack Growth Curve for Austenitic Stainless Steels in PWR Environment

2004 ◽  
Author(s):  
Yuichiro Nomura ◽  
Kazuya Tsutsumi ◽  
Hiroshi Kanasaki ◽  
Naoki Chigusa ◽  
Kazuhiro Jotaki ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Curve ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Stress Intensity Factor Range ◽  
Reference Curve ◽  
Pressurized Water ◽  
Crack Growth Curve

Although reference fatigue crack growth curves for austenitic stainless steels in air environments and boiling water reactor (BWR) environments were prescribed in JSME S NA1-2002, similar curves for pressurized water reactors (PWR) were not prescribed. In order to propose the reference curve in PWR environment, fatigue tests of austenitic stainless steels in simulated PWR primary water environment were carried out. According to the procedure to determine the reference fatigue crack growth curve of BWR, which of PWR is proposed. The reference fatigue crack growth curve in PWR environment have been determines as a function of stress intensity factor range, Temperature, load rising time and stress ratio.

Fatigue Crack Growth Rate Curve for Nickel Based Alloys in PWR Environment

2007 ◽  
Author(s):  
Yuichiro Nomura ◽  
Katsumi Sakaguchi ◽  
Hiroshi Kanasaki
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Stress Ratio ◽  
Austenitic Stainless Steels ◽  
Rising Time

Japanese reference fatigue crack growth rate (FCGR) curves for ferrite and austenitic stainless steels in light water reactor environments are prescribed in JSME S NA1-2004. However, similar reference FCGR curve for nickel-based alloys for pressurized water reactors (PWR) are not prescribed. In order to propose reference FCGR curve for nickel-based alloys, under high stress ratio and low rising time, the effect of the welding method, the effect of specimen orientation and low stress intensity range fatigue crack propagation tests of nickel-based alloys 600, 132 and 82 weld metals were conducted as part of the Environmental Fatigue Test (EFT) projects of Japan Nuclear Energy Safety Organization (JNES). The results show that the effect of heat, welding methods, specimen orientations and environmental water conditions on the FCGR was not significant for Alloys 600, 132 and 82. The FCGR increased with increase of stress ratio, and cyclic loading frequency. According to the procedure for determining the reference FCGR curve of austenitic stainless steels in PWR environment of nickel-based alloys is proposed based on the reference data and the results of this study. The reference FCGR curve for nickel-based alloys in PWR environment are determined as a function of stress intensity factor range, temperature, load rising time and stress ratio.

Fatigue Crack Growth Curve for Austenitic Stainless Steels in BWR Environment

2000 ◽  
Vol 123 (2) ◽  
pp. 166-172 ◽  
Author(s):  
M. Itatani ◽  
M. Asano ◽  
M. Kikuchi ◽  
S. Suzuki ◽  
K. Iida,
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Stainless Steels ◽  
Stress Ratio ◽  
Austenitic Stainless Steels ◽  
Reference Curve

Fatigue crack growth data obtained in the simulated BWR water environment were analyzed to establish a formula for reference fatigue crack growth rate (FCGR) of austenitic stainless steels in BWR water. The effects of material, mechanical and environmental factors were taken into the reference curve, which was expressed as: da/dN=8.17×10−12s˙Tr0.5s˙ΔK3.0/1−R2.121≦ΔK≦50 MPam where da/dN is fatigue crack growth rate in m/cycle, Tr is load rising time in seconds, ΔK is range (double amplitude) of K–value in MPam, and R is stress ratio. Tr=1 s if Tr<1 s, and Tr=1000 s if Tr cannot be defined. ΔK=Kmax−Kmin if R≧0.ΔK=Kmax if R<0.R=Kmin/Kmax. The proposed formula provides conservative FCGR at low stress ratio. Although only a few data show higher FCGR than that by proposed formula at high R, these data are located in a wide scatter range of FCGR and are regarded to be invalid. The proposed formula is going to be introduced in the Japanese Plant Operation and Maintenance Standard.

Effect of Stress Ratio on Fatigue Crack Growth Threshold for Austenitic Stainless Steels in Air Environment

2017 ◽  
Vol 741 ◽  
pp. 88-93 ◽  
Author(s):  
Kunio Hasegawa ◽  
Saburo Usami
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Test Data ◽  
Stainless Steels ◽  
Stress Ratio ◽  
Austenitic Stainless Steels ◽  
R Ratio ◽  
Growth Assessment ◽  
Growth Threshold

The fatigue crack growth threshold ΔKth is an important characteristic of crack growth assessment for the integrity of structural components. However, the accurate threshold ΔKth values for austenitic stainless steels in air environment are lacking in many fitness-for-service (FFS) codes, although fatigue crack growth tests have been performed and many test data had been published. This paper focuses on fatigue crack growth threshold ΔKth values for austentic stainless steel in air environment. The paper introduces the current ΔKth values provided by four major FFS codes and summarizes the available test data based on the literature survey. The paper then discusses the applicability of the existing ΔKth for stainless steels and proposes a new relation as a function of the stress ratio (the R ratio) for use by FFS codes.

scholarly journals High Resistance of Fatigue Crack Growth for Austenitic Stainless Steels Containing Nitrogen.

1999 ◽  
Vol 65 (634) ◽  
pp. 1343-1348 ◽  
Author(s):  
Hisashi HIRUKAWA ◽  
Saburo MATSUOKA ◽  
Etsuo TAKEUCHI ◽  
Takahito OMURA ◽  
Koji YAMAGUCHI ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
High Resistance ◽  
Stainless Steels ◽  
Austenitic Stainless Steels

Mechanisms of Fatigue Crack Growth in WC-Co Cemented Carbides

2005 ◽  
Vol 297-300 ◽  
pp. 1120-1125 ◽  
Author(s):  
Myung Hwan Boo ◽  
Chi Yong Park
Keyword(s):  
Growth Rate ◽  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Crack Growth ◽  
Intensity Factor ◽  
Crack Growth ◽  
Stress Ratio ◽  
Cemented Carbides ◽  
Stress Intensity Factor Range

In order to study the influence of stress ratio and WC grain size, the characteristics of fatigue crack growth were investigated in WC-Co cemented carbides with two different grain sizes of 3 and 6 µm. Fatigue crack growth tests were carried out over a wide range of fatigue crack growth rates covering the threshold stress intensity factor range DKth. It was found that crack growth rate da/dN against stress intensity factor range DK depended on stress ratio R. The crack growth rate plotted in terms of effective stress intensity factor range DKeff still exhibited the effect of microstructure. Fractographic examination revealed brittle fracture at R=0.1 and ductile fracture at R=0.5 in Co binder phase. The amount of Co phase transformation for stress ratio was closely related to fatigue crack growth characteristics.

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