Modeling of Austenitization Kinetics in 5CrNiMoV Steel

5CrNiMoV is a type of high-wear-resistance hot forging die steel, and the description of its austenitization kinetics plays a significant guiding role in industrial application. Based on the dilation curves of 5CrNiMoV steel measured by the DIL805A dilatometer at heating rates of 0.05-50 K/s, a unified model of non-isothermal austenitization kinetics of 5CrNiMoV was derived using the internal state variable (ISV) method, which modeled both the incubation period and the transition period. Material constants in the model were determined using optimization techniques based on genetic algorithms. Additionally, through comparative analysis, the predicted austenite phase transformation volume fraction was in good agreement with experimental results, indicating that the model can effectively describe the austenitization kinetics of 5CrNiMoV steel. Compared with other austenitization kinetics modeling methods, this model, by utilizing the ISV method, possesses not only the advantages of simple formulas and clear physical meanings, but also wide applicability and high stability.