Study on Low-Cycle Fatigue Behavior and Life Prediction of Cr-Ni-Mo-V Gun Steel at Room Temperature and 600 °C

In this paper, the low-cycle fatigue fracture behavior and life prediction of Cr-Ni-Mo-V gun steel at room temperature and 600 degrees C are studied. The results indicated that at room temperature and 600 degrees C, the Cr-Ni-Mo-V gun steel exhibited obvious monotonic softening and cyclic softening. This behavior could be attributed to the formation of dislocation networks, dislocation walls, dynamic recovery, and dynamic recrystallization. As the temperature increased, the failure mode gradually shifted from mixed transgranular and intergranular fractures to intergranular fractures possibly owing to the reduced grain boundary strength and easy oxidation of the grain boundary at high temperatures. In addition, the fatigue life prediction model considering the influence of temperature is established by using the energy dissipation quadratic function, offering a practical method to improve the fatigue performance evaluation of Cr-Ni-Mo-V gun steel at various temperature.