Elastic-Plastic Fracture Mechanics Analysis on Environmentally Accelerated Cracking of Stainless Steel in High Temperature Water

Abstract

Stress corrosion crack growth during slow strain rate testing was investigated using elastic-plastic fracture mechanics. Thin compact and center-notched specimens of sensitized Type 304 stainless steel were examined at different extension rates in high temperature oxygenated water. The analytical results showed that the crack growth rate has a best correlation with a time differential of the J-integral, which is an estimate of a crack tip deformation rate. Based on the analysis, a new mechanistic model under both monotonic and cyclic loadings was suggested, where cracking was classified into three categories depending on the environmental acceleration, i.e., mechanical cracking, corrosion enhanced mechanical cracking, and stress corrosion cracking.