Determination of Hot Workability of 5Cr5MoSiV1 Steel Based on Hot Processing Map

Abstract

The evaluation of the hot workability of 5Cr5MoSiV1 steel with high deformation resistance is crucial for the controllability of the hot forging process. Based on the isothermal compression at deformation temperature of 950–1200 °C and strain rate of 0.01–10 s−1, the flow behavior of 5Cr5MoSiV1 steel is demonstrated. As the strain rate increases, the typical characteristics of the true stress–strain curve indicate that the dynamic softening mechanism changes from dynamic recrystallization to dynamic recovery. Moreover, the hot working window determined by the hot processing map from the modified J–C constitutive model is constructed for the forging process of the material. Through microstructure verification, the optimal hot working window is within the range of deformation temperature from 1000 to 1185 °C and strain rate from 0.01 to 0.202 s−1. Furthermore, the forging upsetting tests of the large cylindrical specimens are used to confirm the insecurity of hot deformation parameters outside the optimum hot working window. The implementation of this study can provide a theoretical basis for the determination of hot forging process parameters for 5Cr5MoSiV1 steel.