Effect of Residual Stress and Hardening on Grain Boundary Sliding in Welds of Low-carbon Stainless Steels with Surface Machining
森 裕章 Hiroaki MORI 勝山 仁哉 Jinya KATSUYAMA 望月 正人 Masahito MOCHIZUKI 西本 和俊 Kazutoshi NISHIMOTO
Grain boundary sliding Intergranular stress corrosion cracking (IGSCC) Low-carbon austenitic stainless steel Residual stress Surface machining Welds Work hardening
To clarify the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in welds of low-carbon austenitic stainless steels with surface machining, residual stress and hardness were evaluated by 3-dimentional thermo elastic-plastic analysis and grain boundary sliding behavior was examined using a constant strain rate tensile test. It was revealed that grain boundary sliding occurred in the material at 561K by the tensile test with the numerically simulated tensile residual stress due to multi-pass welding and surface machining. In addition, it was clarified that the grain boundary energy is raised by the grain boundary sliding. On the basis of these results, it was concluded that the cause of IGSCC in the welds of low-carbon austenitic stainless steel with surface hardening is the increase in grain boundary energy due to grain boundary sliding induced by residual stress of multi pass welding and surface hardening.