Effect of Cr and Ni on SCC Susceptibility in Non-sensitized Materials under Simulated BWR Condition

Abstract

The effect of Cr and Ni on Stress Corrosion Cracking （SCC） susceptibility was studied in non-sensitized materials under simulated BWR condition. SCC tests were conducted by creviced 4 bent beam test as static strain method, and Slow Strain Rate Test （SSRT） as dynamic strain method. Cr affected markedly to prevent SCC in both SCC tests. Ni was effective to reduce SCC susceptibility under the dynamic strain test, however, not clear to affect SCC susceptibility under the static strain test. The effect of Cr was discussed for corrosion resistant film by examining strain electrode behavior and corrosion products. With increasing the Cr content in material, the repassivation behavior was improved and Cr concentration in inner side of corrosion product increased. These results suggest that Cr affects to suppress SCC due to improve corrosion resistance by Cr concentrated corrosion film.