Influence of Long-Term Thermal Aging on SCC Initiation Susceptibility of L-grade Austenitic Stainless Steel

摘要

The influence of the long-term thermal aging (LTA)on the SCC susceptibility to initiation in L-gradeaustenitic stainless steels were studied. In this study,creviced bent beam (CBB) testing was performed on both20% cold-worked Type 316L SS and that with the LTAtreatment at 288 °C for 14,000 hours. The results showedan increase of SCC susceptibility after the LTA treatment.Additionally, SEM observations were conducted on thespecimen surfaces before and after CBB testing.Microstructural examination revealed a change in thedeformation mode after the LTA treatment, that is, areduction in dislocation motion and an increase ofdeformation twinning. The causes of such changes indeformation microstructure and its correlation with theSCC susceptibility to initiation are discussed in this paper.