The effect of applied potential on the stress corrosion cracking of sensitized type 316 stainless steel in high temperature water

The effect of applied potential on the stress corrosion cracking (SCC) behaviour of sensitized type 316 stainless steel (SS) in high temperature water containing 5 ppm chloride over the temperature range from 100 to 300 °C has been investigated using the slow strain rate test (SSRT) technique. The results are compared with previously published data for annealed 316 SS. Annealed 316 SS showed two ranges of potential over which transgranular cracking occurred whereas the sensitized material showed a wide range of potential for cracking and a transition from transgranular to intergranular cracking with increasing applied potential. The sensitized 316 SS was more susceptible to SCC than the annealed steel but the SCC of both seem to be controlled by an anodic dissolution mechanism. AES analyses of the oxide films formed on the surface of stress corrosion specimens suggest that the susceptibility to SCC of 316 SS evaluated by SSRTs decreased as the degree of enhancement of nickel in the oxide films increased.