The Stress Intensity Factor Dependence of 304 Stainless Steel SCC growth in Deaerated Water

摘要

Stress corrosion crack growth rate (SCCGR) tests were conducted on 304 stainless steel (SS) in hydrogen deaerated water to characterize the dependence with the stress intensity factor (K). Tests were performed on four 304SS heats at 321 and 328°C at K levels that ranged from 22 to 89 MPa√m. Two test strategies were utilized to quantify the SCCGR K dependence. The majority of autoclave tests were single or dual specimen tests in which multiple K levels were step wise investigated and SCCGRs were evaluated through in-situ direct current electrical potential drop. Single K level specimen tests were performed on one 304SS heat at K levels of 25, 51 and 74 MPa√m. Results showed power law SCCGR K functionality with power law exponents which ranged from 0.9 to 3.0. The K functionality measured from the single condition tests was lower than those measured in single specimen multiple K conditions tests. The 304SS SCCGR vs. K results, as well as the role of uncracked ligaments on electrical potential drop (EPD) crack growth rate measurements and crack opening displacement, are discussed.