2023 Volume 72 Issue 6 Pages 182-189
Aim of this study is to make clear both the relaxation of compressive residual stresses and the property change of shot-peened Type-316 stainless steel by thermal aging at 190℃ in air. Here, the Type-316 stainless steel is planned to be the material of dry storage vessel （canister） for the used nuclear fuel. We found that the stress relaxation ratio: m （defined as the ratio of stresses after aging against the stresses before aging or at being peened） was kept to be higher than 0.8, even after the aging over 35,000 hours. We also found that change of material properties such as surface hardening by the thermal aging was weak. We did not observe any intergranular （IG） cracks over 35,000 hour, while severe IG-cracks did occur by aging at 340℃ in air, as reported in the previous paper.
