Sensitization and SCC [stress corrosion cracking] study on thermally treated inconel 600

Stress corrosion cracking (SCC) was recently discovered to be the major cause of failure in Inconel 600 used in steam generator (SG) tubes of pressurized water reactors (PWRs). The failure of the Three Mile Island SG tubes has been attributed to low-temperature SCC in the sulfur-contaminated environment under cold shutdown conditions. Bandy et al. found that even in the 10-6 M Na2S2O3 (or N2S4O6) environment, the SCC would still be observable. This study investigates the effect of thermal treatment on the sensitization of Inconel 600 and studies the SCC behavior of this alloy in a sulfur-contaminated environment (S2O3-2) using constant load test. The results of this study can be used to correlate the SCC susceptibility to the degree of sensitization of Inconel 600 by defining a critical chromium concentration under the test conditions