Phenomenological model for stress corrosion cracking of Types 316NG and 316 stainless steel. [BWR]

摘要

A phenomenological model for both intergranular and transgranular stress corrosion cracking (SCC) in constant extension rate (CERT) tests is discussed. The model is based on an estimate of crack-tip strain rate obtained by use of a J-integral approach, a slip dissolution model for SCC, and a J-integral fracture criterion. The model is used to derive correlations between the SCC parameters (such as time to failure and average crack growth rate) and applied (nominal) strain rate. The model is extended to determine similar relationships between the SCC parameters and average near-crack-tip strain rate. The model predictions are compared with CERT test results obtained for Type 316NG stainless steel (SS) in water containing dissolved oxygen and impurities at 289/sup 0/C over a range of strain rates between 10/sup -5/ and 10/sup -7//s. Good agreement is obtained between the theoretical description and experimental results. The SCC behavior of Type 316NG SS is also compared with that of Type 316 SS to determine the relative SCC susceptibility of the two materials.