Effect of surface finish on SCC susceptibility of 316L stainless steel in high-temperature oxygenated water

Abstract

Near-surface characteristics and SCC susceptibility in high-temperature oxygenated water were evaluated for several 316L stainless steels with different surface finish conditions. Vickers hardness test results showed that near-surface hardening was more pronounced in the following order: as-received, end-milled, grinder-finished, #600 emery paper-finished, and colloidal silica abrasive-finished. The as- received material showed a surface hardening layer due to machining and intergranular grooves of micrometer scale depth due to pickling were found over the entire surface area. SCC susceptibility and crack propagation paths (transgranular/intergranular) differed depending on the surface finish condition. For the as-received material, SCC was initiated at the bottom of the intergranular grooves and propagated along the grain boundary. Therefore, intergranular grooves by pickling were found to increase the SCC susceptibility of low-carbon stainless steels.