Experimental and FEM investigation of dynamic and static recrystallization with grain growth in SCM440 steel during hot compression

This study presents a comprehensive experimental and numerical investigation of the dynamic and static recrystallization as well as grain growth behavior in SCM440 steel during hot compression. Compression tests were carried out at temperatures ( T ) of 850, 950, 1050, 1150, and 1250 °C and strain rates ( ) of 0.1, 1, 5, 10, and 20 s -1 to evaluate microstructural evolution under various thermomechanical conditions. The average grain sizes corresponding to each deformation and post-deformation condition were measured to characterize the progression from dynamic recrystallization (DRX) to static recrystallization (SRX) and subsequent grain growth (GG). A coupled optimization technique integrating AFDEX, a metal forming simulator, with Altair HyperStudy was employed to determine the optimal kinetic grain sizes parameters governing recrystallization and growth behavior. This coupling enabled iterative calibration between finite element method (FEM) simulations and experimental measurements, resulting in a unified kinetic model capable of accurately predicting grain-size evolution during both deformation and annealing stages. The predicted results exhibited excellent agreement with experimental data. The proposed FEM–based coupled optimization framework provides a robust and efficient approach for modeling complex microstructural phenomena and offers valuable insights for the design and control of hot forming processes in medium-alloy steels.