Thermal-mechanical Coupling Behavior Analysis and Fatigue Life Prediction of Hot Rolled High-speed Steel Composite Rolls

Periodic thermal loads-induced temperature gradients and thermal stresses are the dominant factors leading to thermal fatigue failure of hot rolling work rolls. In this study, an elastoplastic finite element model based on actual hot rolling conditions was established to systematically analyze the evolution of temperature and thermal stress fields in high-speed steel work rolls. The influence mechanisms of rolling parameters (including initial work roll temperature, strip rolling temperature, and rolling speed) on the thermo-mechanical coupling behavior were investigated. The Manson-Coffin formula, considering multiaxial stress effects, was employed to predict the thermal fatigue crack initiation life of the work rolls. The results demonstrate that the numerical simulation model can accurately predict the distribution characteristics of the temperature and stress fields in the work rolls. The rolling parameters significantly regulate the thermo-mechanical coupling behavior of the work rolls. The fatigue crack initiation life of the work rolls, estimated using different fatigue parameter methods, is N_f=8874 cycles