Mechanical degradation of cold-worked 304 stainless steel in salt spray environments

Saline corrosion is one of the major degradation mechanisms for stainless steel 304 (SS304) spent fuel canisters during the dry storage period. Slow strain rate tensile tests (SSRT) were conducted to determine the tensile strength and notched tensile strength (NTS) of cold-rolled SS304 in 0.5 and 5 wt% saline spray environments at 358 K. The YS and UTS of the steels did not decrease significantly in the 0.5 wt% saline spray environment, but a remarkable decrease in elongation was observed in the 5 wt% saline spray. Furthermore, a notch could exacerbate the saline corrosion degradation and aggravate the hydrogen embrittlement of SS304. The cold work of higher degrees could slightly improve SCC resistance of the SS304 under the lower chloride containing spray. However, the NaCl concentration is a crucial factor affecting the SCC susceptibility of SS304.