Microstructural evolution and dynamic recrystallization mechanisms of 12Cr2Mo1V steel during hot deformation

The increasing size of 12Cr2Mo1V steel hydrogenation reactor shells leads to a heightened risk of abnormal grain coarsening during hot forming. To address this issue, this study systematically investigates the hot deformation behavior focusing on the dynamic recrystallization (DRX) of the steel through a combined experimental and numerical simulation approach. Isothermal compression tests were conducted over a temperature range of 900–1200 °C and strain rates of 0.01–5 s −1 . The results reveal a temperature-dependent transition in the dominant DRX mechanism. Continuous dynamic recrystallization (CDRX) prevails at lower temperatures, while discontinuous dynamic recrystallization (DDRX) becomes dominant at higher temperatures. Additionally, annealing twinning was identified as an auxiliary DRX mechanism under high-temperature and high-strain-rate conditions. Predictive models for DRX grain size (R 2 = 0.9864) and DRX kinetics (R 2 = 0.9714) were developed from the experimental data. These models were implemented in the finite element software FORGE® to simulate the DRX behavior during hot deformation. The simulated DRX volume fractions and grain sizes show good agreement with experimental results. The integrated experimental and simulation framework provides quantitative guidance for optimizing thermo-mechanical processing parameters to achieve uniform and fine-grained microstructures in large forgings.