Fatigue Crack Growth for Subsurface Flaws Near Component Surface and Proximity Rules

If a subsurface flaw is located near a component surface, the subsurface flaw is transformed to a surface flaw in accordance with a flaw-to-surface proximity rule. The re-characterization process from subsurface to surface flaw is adopted in all fitness-for-service (FFS) codes. However, the criteria of the re-characterizations are different among the FFS codes. Cyclic tensile experiment was conducted on a carbon steel flat plate with a subsurface flaw at ambient temperature. The objective of this paper is to compare the experiment and calculation of fatigue crack growth behavior for a subsurface flaw and the transformed surface flaw, and to describe the validity of the flaw-to-surface proximity rule defined by ASME Code Section XI, JSME S NA1 Code and other codes.

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Comparison of Experiment and Calculation on Fatigue Crack Growth for Transformed Surface Flaw

Volume 1: Codes and Standards ◽

10.1115/pvp2012-78688 ◽

2012 ◽

Cited By ~ 2

Author(s):

Kunio Hasegawa ◽

Yinsheng Li ◽

Katsumasa Miyazaki ◽

Koichi Saito

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Growth Behavior ◽

Surface Flaw ◽

Crack Growth Behavior ◽

Fatigue Crack Growth Behavior ◽

Asme Code ◽

Tensile Experiment ◽

Surface Proximity

If a subsurface flaw is located near a component surface, the subsurface flaw is transformed to a surface flaw in accordance with a flaw-to-surface proximity rule. The re-characterization process from subsurface to surface flaw is adopted in all fitness-for-service (FFS) codes. However, the criteria of the re-characterizations are different among the FFS codes. Cyclic tensile experiment was conducted on a carbon steel flat plate with a subsurface flaw at ambient temperature. The objective of this paper is to compare the experiment and calculation of fatigue crack growth behavior for a subsurface flaw and the transformed surface flaw, and to confirm the flaw-to-surface proximity rule defined by ASME Code Section XI and JSME S NA1 Code.

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Study on Flaw-to-Surface Proximity Rule for Transforming Subsurface Flaws to Surface Flaws Based on Fatigue Crack Growth Experiments

Journal of Pressure Vessel Technology ◽

10.1115/1.4028423 ◽

2015 ◽

Vol 137 (4) ◽

Cited By ~ 3

Author(s):

Kunio Hasegawa ◽

Yinsheng Li ◽

Koichi Saito

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Surface Flaw ◽

Crack Growth Behavior ◽

Surface Flaws ◽

Asme Code ◽

Tensile Experiment ◽

Growth Experiments ◽

Surface Proximity

If a subsurface flaw is located very near a component surface, the subsurface flaw is categorized as a surface flaw. The boundary of the subsurface and surface flaws is required for flaw evaluation. The subsurface flaw is transformed to a surface flaw in accordance with a flaw-to-surface proximity rule. The recharacterization process from subsurface to surface flaw is adopted in all fitness-for-service (FFS) codes. However, the specific criteria of the recharacterizations are different among the FFS codes. Cyclic tensile experiment was conducted on a carbon steel flat plate with a subsurface flaw at ambient temperature. The objective of the paper is to compare the experiment and calculation of fatigue crack growth behavior for a subsurface flaw and the transformed surface flaw, and to check the validity of the flaw-to-surface proximity rule defined by ASME Code Section XI, JSME S NA1 Code and other codes.

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Analysis of Environmental Fatigue Crack Growth Behavior of Type 347 Stainless Steels Under Simulated PWR Water Conditions

Volume 1A: Codes and Standards ◽

10.1115/pvp2017-65563 ◽

2017 ◽

Author(s):

Seokmin Hong ◽

Ki-Deuk Min ◽

Soon-Hyeok Jeon ◽

Bong-Sang Lee

Keyword(s):

Stainless Steel ◽

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Stainless Steels ◽

Growth Behavior ◽

Crack Growth Behavior ◽

Fatigue Crack Growth Behavior ◽

Water Conditions ◽

Asme Code

In this study, the fatigue crack growth behavior of Type 347 stainless steel (SS) used in pressurizer surge line in Korea Standard Nuclear Power Plant was analyzed. Environmental fatigue crack growth rates (FCGRs) were evaluated using pre-cracked compact tension (CT) specimens under the various simulated PWR water conditions; different levels of dissolved oxygen (DO) and loading frequencies. FCGRs of 347SSs were accelerated under PWR water conditions. When DO levels increased and frequency decreased, FCGR of 347SS increased. Under the more corrosive environment at crack tip, FCGRs were accelerated more. FCGRs of 347SSs under PWR water condition were compared with reference FCGR curves of stainless steel in ASME code section XI, ASME Code Case N-809, and JSME based on FCGR data of 304SS and 316SS. In this study, FCGRs of 347SS were slightly faster than reference curves in JSME under PWR environment but slower than that in JSME under BWR environment. Compared to reference FCGR curve in ASME Code Case N-809, FCGRs of 347 stainless steels are similar or slightly higher.

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