Hot deformation behavior and hot-metal-gas-forming process of V micro-alloyed high manganese steel

The hot deformation behavior of a newly designed V micro-alloyed high manganese steel (HMnS) was investigated in order to guide the development of the hot-metal-gas-forming process. Single-pass hot compression experiments were conducted in the temperature range of 950-1100 degrees C and the strain rate range of 0.05-10 s-1, and the stress-strain curves and the corresponding softening mechanism of the V micro-alloyed HMnS were analyzed. Results show that two types of stress-strain curves, representing the work hardening (WH)-dynamic recovery (DRV)-dynamic recrystallization (DRX) mechanism and the WH-DRV mechanism, respectively, occur during the deformation process. Moreover, the WH-DRV-DRX mechanism gradually transforms into the WH-DRV mechanism with the increasing strain rate and decreasing deformation temperature. Two types of constitutive models considering the softening mechanism difference were established and verified by additional hot-deformation experiments. Hot processing map of the HMnS was established and correlated well with the microstructure evolution result. Based on the constitutive models and processing map, the optimal processing parameter range and flow stress of HMnS for the hot-metal-gas-forming were determined.