Corrosion and stress corrosion cracking behavior of 316 L stainless steel produced by additive manufacturing wire processes in water environments

Abstract

Stress corrosion cracking (SCC) and oxidation tests were performed on 316L stainless steel manufactured by wire laser additive manufacturing (WLAM) in hydrogenated Pressurized Water Reactors (PWR) environment. The influence of stress-relief and solution annealed heat treatments on microstructure and mechanical properties was assessed and compared to conventionally manufactured 316L. Oxidation tests revealed similar corrosion behavior between WLAM and conventional solution-annealed Stainless Steels (SS). The cracks network after SSRT tests was estimated by SEM observations. Intergranular stress corrosion cracking (IGSCC) was detected in solution-annealed (SA) samples while only transgranular cracks were identified in stress-relieved (SR) ones. Results show that a high temperature heat treatment significantly affected the SCC susceptibility of WLAM samples. It is believed that the high-density delta ferrite, which was only observed in the SR samples, may affect the cracking mode, and lead to the formation of short transgranular cracks.