1 School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China 2 Technical Management Department, Jiangsu Yinhuan Precision Steel Tube Co., Ltd., Yixing 214200, Jiangsu, China 3 College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China 4 School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing 211167, Jiangsu, China
Dynamic recrystallization behavior and coincidence site lattice evolution in thermal deformation of 316H stainless steel used in nuclear systems
1 School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China 2 Technical Management Department, Jiangsu Yinhuan Precision Steel Tube Co., Ltd., Yixing 214200, Jiangsu, China 3 College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China 4 School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing 211167, Jiangsu, China
摘要 The hot deformation behavior of 316H stainless steel used in the 4th-generation nuclear systems was investigated by thermal compression tests at 1000–1150 C and 0.01–10 s-1. It was found that true stress firstly increased and then decreased with the increasing strain rate with a threshold of 1 s-1. Electron backscatter diffraction was used to analyze the microstructure evolution. Discontinuous dynamic recrystallization (DDRX) was the dominant dynamic recrystallization (DRX) mechanism, while continuous dynamic recrystallization (CDRX) was the supplementary one. DDRX happened before CDRX and provided additional nucleation sites for the latter. Twin grain boundaries (R3) appeared in DRX grains due to growth accidents. As the length fraction of R3 increased, the coincidence site lattice (CSL) boundary transition began to occur, forming R9 and R27. After the occurrence of full DRX, the growth and annexation of DRX grains were easy to be promoted, in which progress both equiaxed grains and CSL boundaries disappeared. The ideal deformation microstructure with fine and uniform DRX grains, which was accompanied by a high length fraction of CSL boundaries, appeared at 1000 °C–0.01 s-1, 1050 °C–0.01–0.1 s-1, 1100 °C–0.1–1 s-1 and 1150 °C–1–10 s-1. That is, the deformation conditions mentioned above were the preferable thermal forming parameters for 316H stainless steel in actual productions.
Abstract：The hot deformation behavior of 316H stainless steel used in the 4th-generation nuclear systems was investigated by thermal compression tests at 1000–1150 C and 0.01–10 s-1. It was found that true stress firstly increased and then decreased with the increasing strain rate with a threshold of 1 s-1. Electron backscatter diffraction was used to analyze the microstructure evolution. Discontinuous dynamic recrystallization (DDRX) was the dominant dynamic recrystallization (DRX) mechanism, while continuous dynamic recrystallization (CDRX) was the supplementary one. DDRX happened before CDRX and provided additional nucleation sites for the latter. Twin grain boundaries (R3) appeared in DRX grains due to growth accidents. As the length fraction of R3 increased, the coincidence site lattice (CSL) boundary transition began to occur, forming R9 and R27. After the occurrence of full DRX, the growth and annexation of DRX grains were easy to be promoted, in which progress both equiaxed grains and CSL boundaries disappeared. The ideal deformation microstructure with fine and uniform DRX grains, which was accompanied by a high length fraction of CSL boundaries, appeared at 1000 °C–0.01 s-1, 1050 °C–0.01–0.1 s-1, 1100 °C–0.1–1 s-1 and 1150 °C–1–10 s-1. That is, the deformation conditions mentioned above were the preferable thermal forming parameters for 316H stainless steel in actual productions.
Le-li Chen,Rui Luo,Pei Gao, et al. Dynamic recrystallization behavior and coincidence site lattice evolution in thermal deformation of 316H stainless steel used in nuclear systems[J]. Journal of Iron and Steel Research International, 2023, 30(09): 1862-1872.
2023, Vol. 30 
