2022 Volume 63 Issue 11 Pages 1533-1540
Under the conditions of deformation temperature of 900∼1200°C and strain rate of 0.01∼10 s−1, the single pass isothermal compression test of CF170 maraging stainless steel was carried out on the Gleeble-3800 thermal compression simulator, and its flow stress curve was measured. Based on the Arrhenius model and Avrami model, the flow stress model considering strain compensation and dynamic recrystallization volume fraction model were established according to the flow stress curve. The results showed that the dynamic recrystallization of CF170 steel occurs in advance compared with other steels, and the relationship between the critical strain of dynamic recrystallization and the peak strain is εc = 0.44 εp. CF170 steel is sensitive to the deformation temperature and strain rate. The temperature required for complete dynamic recrystallization is relatively low at a low strain rate. In addition, although the flow stress curve does not show the characteristics of dynamic recrystallization under the high temperature and high strain rate, partial dynamic recrystallization still occurs. In addition, the hierarchical relationship between the martensite and austenite was analyzed by Electron Back-Scattered Diffraction. The results showed that a prior austenite grain is divided into multiple martensite packets, subsequently a packet is divided into several martensite blocks.
