Stress–Strain Response of AISI H13 Steel Subjected to Cyclic Thermomechanical Loading

ABSTRACT This study investigates the stress–strain behavior of AISI H13 hot work die steel under thermomechanical fatigue (TMF) conditions. An electromagnetic‐thermal‐mechanical coupled finite element model was established to analyze the temperature and stress evolution during TMF cycles. Experimental results reveal that as TMF cycles increase, the hysteresis loop areas expand, and maximum tensile and compressive stress values decrease, indicating cyclic softening of AISI H13 steel. After undergoing TMF, observations show martensitic lath recovery and carbide coarsening along boundaries. Numerical results indicate thermal cycles cause temperature field inhomogeneity along the axial direction, which leads to a non‐uniform distribution of internal stresses along the longitudinal axis. Besides, the TMF lifetime under numerical simulation is comparable to that obtained through experiments. Based on experimental and simulation data, four life prediction models are employed, with the Ostergren model showing the highest consistency with a reliability factor of 1.2.