SCC initiation susceptibility in L-grade austenitic stainless steels after long-term thermal aging treatment

Kaji, Yoshiyuki  ; Kondo, Keietsu  ; Aoki, So  ; Hirade, Tetsuya  ; Yamamoto, Masahiro 

To clarify the causal relationship between the LTA treatment and the SCC initiation susceptibility, microstructural analyses on 316L CW specimens before and after the LTA treatment have been conducted. One of viewpoints in our research is the deformation microstructure. Results of the surface examination by SEM on CBB tested specimens suggested the difference in the deformation microstructure of 316L CW and CW+LTA. Coarse and planar slip steps were frequently observed on the surface of 316L CW+LTA specimens, indicating the localization of dislocation motion to limited slip planes. On the other hand, surface morphology observed in 316L CW was mainly fine and wavy slip step, indicating the occurrence of the homogeneous plastic deformation. The detail mechanism of the change in the deformation microstructure by the LTA treatment is unknown yet. Researches on its effect on the deformation microstructure and, furthermore, the SCC susceptibility is now in progress.