Study on the Thermal Deformation Behavior of Cr–Mn–Si High‐Strength Steel and Determination of Grain Refining Parameter Pathways

In order to study the deformation behavior of 30CrMnSiNi2A high‐strength steel during thermal forming, a series of hot compression experiments are conducted under deformation conditions in the temperature range of 850–1200 °C and true strain rates of 0.1, 0.5, 1, and 10 s −1 . Based on the experimental data, the modified Johnson–Cook equation is calculated, and then the backpropagation artificial neural network constitutive model (BP‐ANN) is obtained. By comparison, the BP‐ANN has obvious advantages in describing and predicting the flow behavior of the material. The thermal processing map is drawn to delineate the three regions of dynamic recrystallization, dynamic recovery, and instability region, which is combined with the microstructure map to determine the critical value dominated by the occurrence of dynamic recrystallization mechanism and to construct the deformation mechanism map. At a fixed temperature, finite element simulations are carried out sequentially for different strain stages to determine the average grain size of each stage and determine the optimal parameter loading path. It helps to realize the effective control of the microstructure of the material, to obtain the ideal grain refinement effect.