Dynamic Recrystallization Behavior of 7Cr7Mo2VSiNi Tool Steel during Hot Deformation by Experiments and Numerical Simulations

To investigate the hot deformation behavior of 7Cr7Mo2VSiNi steel, hot compression tests were carried out in a temperature range of 950-1150 °C and a strain rate range of 0.005-5 s⁻¹ using a Gleeble-3500 testing machine. After hot compression testing, the microstructures of the samples were observed by an optical microscope. Based on the flow stress–strain curves, the dynamic recovery model and dynamic recrystallization (DRX) model were established. The flow stress was predicted according to the established model, which was in good agreement with the experimental results. The correlation coefficient (R) and the average absolute relative error were 98.9% and 2.52%, respectively. According to the DRX grain size, the grain size evolution model was established. The established material model was imported into DEFORM-3D to simulate the strain field, DRX softening rate and average grain size of 7Cr7Mo2VSiNi during single-pass hot compression. The simulation results were in good agreement with the experimental results, indicating that the finite element method (FEM) served as an effective simulation method. Furthermore, the processing maps were established based on the dynamic materials model. The optimal processing parameters for the 7Cr7Mo2VSiNi alloy steel were determined based on the processing maps, microstructure and simulation values.