Eliminating mixed grain structure of Fe–22Cr–25Ni austenitic heat–resistant steel via strain–induced M23C6 precipitation and re–dissolution
Hongwei Zhou, Liangwei Fang, Junqiang Cong, Fengmei Bai, Liqiang Zhang, Ali Naqash, Jianhua Chu, Dongming Liu, Yizhu He
Abstract
Austenitic stainless steels are prone to mixed grain structure (MGS) defect during solution treatment or hot work. We demonstrate that strain–induced continuous M 23 C 6 precipitates at grain boundaries (GBs) enable obtaining uniform deformed structures through hot–rolling at 1000 °C and 1100 °C. After solution treatment of the hot–rolled specimens at 1200 °C for 10–60 min, static recrystallization occurs. After the solution time exceeds 10 min, the M 23 C 6 precipitates at GBs dissolve completely. The recrystallized grains grow normally as the solution time increase, and there is no abnormal grain growth. Strain–reduced the M 23 C 6 precipitation can pin GBs during the dissolution process, thereby eliminating MGS defect.