A comparative study on Johnson-Cook, modified Johnson-Cook and Arrhenius-type constitutive models to predict the high temperature flow stress in 20CrMo alloy steel

The isothermal hot compression tests were conducted on a Gleeble-1500D thermal simulation machine, in a wide range of temperatures (1173-1373 K) and strain rates (1.5 × 10−3-1.5 × 10−2 s−1). Based on the experimental true strain-true stress data, the Johnson-Cook, modified Johnson-Cook and Arrhenius-type constitutive models were established for a 20CrMo alloy steel. A comparative study has been made on the accuracy and effectiveness of the three models to predict the high temperature flow stress. The results show that the predicted values by the Johnson-Cook model could not agree well with the experimental values except for under reference deformation conditions. However, the modified Johnson-Cook and Arrhenius-type models, which consider the coupled effects of strain rate and deformation temperature, could give a precise prediction of high temperature flow stress for the studied steel.