Liquid-Metal Embrittlement of Type 316L Stainless Steel by Gallium as Measured by Elastic-Plastic Fracture Mechanics

CORROSION ◽  
2004 ◽  
Vol 60 (3) ◽  
pp. 254-261 ◽  
Author(s):  
D. G. Kolman ◽  
R. Chavarria
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Crack Growth Rate ◽  
Fracture Mechanics ◽  
Liquid Metal ◽  
Crack Growth ◽  
Liquid Metal Embrittlement ◽  
Intergranular Cracking ◽  
Elastic Plastic ◽  
Type 316L

Abstract In order to bound failure of austenitic stainless steel storage containers housing Ga-containing compounds, the liquid-metal embrittlement of Type 316L (UNS S31603) stainless steel (SS) by Ga was investigated. Type 316L SS compact tension specimens were exposed to liquid Ga using a depassivation technique to wet the specimen. Linear elastic and elastic-plastic fracture mechanics methods were used to compare the fatigue and fracture behavior. Mild liquid-metal embrittlement was observed, as indicated by increased fatigue crack growth rate, decreased number of fatigue cycles to failure, decreased crack initiation resistance, and increased crack growth rate. Stable cracking was observed for all test conditions. A small amount of intergranular cracking was observed following Ga exposure. No effect of test temperature on embrittlement was observed over the small temperature range examined (35°C to 75°C). Decreasing crosshead displacement rate promoted Ga embrittlement. Based on fractography, profilometry, and mechanics, it appears that both adsorption-induced decohesion and adsorption-enhanced plasticity mechanisms are operative in the Type 316L SS-Ga system.

Evaluation of SCC Crack Growth Rate in BWR Water Based on Elastic-Plastic Fracture Mechanics Parameters

2015 ◽  
Author(s):  
Masahiro Takanashi ◽  
Yu Itabashi ◽  
Takashi Hirano
Keyword(s):  
Growth Rate ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Crack Growth Rate ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Crack Growth ◽  
Growth Rates ◽  
Elastic Plastic ◽  
Crack Growth Rates

This paper presents an applicability of elastic-plastic fracture mechanics parameters for evaluating a crack growth rate of stress corrosion cracking (SCC). Currently linear fracture mechanical approaches have been applied for the SCC crack growth evaluation, even though some cracks due to SCC are found in plastic deformation zones near welding where linear fracture mechanics is no longer applicable. In this paper, the authors have proposed an elastic-plastic parameter “equivalent stress intensity factor KJ” for evaluating the SCC crack growth rate based on the J-integral value, which is valid in both elastic and plastic stress fields. In order to verify the applicability of the evaluation by KJ, SCC crack growth tests were carried out in a simulated boiling water reactor (BWR) water. When the SCC crack growth rate was evaluated by the stress intensity factor K, no linear relationship between the K values and the crack growth rates was observed in the high K-value region, where a small-scale yielding condition was not met. The crack growth rates increased exponentially according to increasing the stress intensity factor to exceed the linear relationship. On the other hand, when the crack growth rate was evaluated by the elastic-plastic parameter KJ, a linear correlation between the KJ values and the crack growth rates was confirmed regardless the specimen size and the stress condition. This result suggests that by applying the elastic-plastic parameter KJ, the SCC crack growth rates in a wider range could be estimated easily with using a smaller specimen.

Effects of a Single Overload on Fatigue Crack Growth of Type 316 Stainless Steel

2021 ◽  
Author(s):  
Koji Miyoshi ◽  
Masayuki Kamaya
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Opening ◽  
Constant Amplitude ◽  
Single Overload ◽  
Tensile Overload

Abstract The effect of a single overload on the fatigue crack growth rate was investigated for Type 316 stainless steel. Fatigue crack growth tests were conducted by controlling strain and load. Tensile and compressive overloads were applied during constant amplitude cycling. The overload ratio, which was defined as the ratio of overload size to baseline constant amplitude, was also changed. The constant amplitude tests were conducted at the strain or the stress ratio of −1.0 which was defined as the ratio of the minimum value to the maximum value. The crack opening point was obtained by the unloading elastic compliance method. The crack growth rate increased after the single compressive overload. The accelerating rate increased with the overload ratio. In contrast, not only the acceleration but also the retardation of the crack growth rate was observed for some tensile overload cases. The crack growth rate increased for relatively small tensile overload cases and decreased for relatively large tensile overload cases. The change in the crack opening level was examined. The crack growth rates after tensile and compressive single overloads correlated with the effective strain and stress intensity factor ranges both for load and strain controlling modes.

Sign in / Sign up

Export Citation Format

Share Document