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

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.

Frequency Effects in the Elevated Temperature Crack Growth Behavior of Austenitic Stainless Steels—A Design Approach

1979 ◽  
Vol 101 (2) ◽  
pp. 171-176 ◽  
Author(s):  
L. A. James
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Correction Factor ◽  
Stainless Steels ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Standard Frequency ◽  
Frequency Correction

The fatigue-crack growth behavior of annealed types 304 and 316 stainless steels is determined over a range of cyclic frequencies in an air environment at temperatures of 800°F (427°C), 1000°F (538°C) and 1200°F (649°C). A good portion of the experimental data supports the observation that the fatigue crack growth rates at a given value of ΔK increases with decreasing frequencies. The behavior ot each temperature is normalized relative to the behavior at a “standard” frequency of 40 cpm, and a simple frequency correction factor is derived. This frequency correction factor, more applicable to type 304 than to 316 stainless steels, is further coupled with temperature effects data taken at the “standard” frequency and combined with a stress ratio correction to furnish estimates of the fatigue crack growth behavior of those two steels over a fairly wide range of parameters.

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

2013 ◽  
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 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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