Prediction of High Temperature Flow Stress for AISI 4120 Steel during Hot Compression

To investigate the hot deformation behaviors of AISI 4120 steel, isothermal compression tests were conducted using Gleeble-1500 thermal-mechanical simulator in the temperature range of 1073-1373K with the strain rate of 0.01-10s-1. The hyperbolic sine law in Arrhenius type is used in the constitutive modeling for AISI 4120. The influence of strain is incorporated in constitutive analysis by considering the effect of strain on material constants α, n, Q and ln A. The flow stress values predicted by the developed constitutive equations show a good agreement with experimental results, which reveals that the developed constitutive equations could give an accurate and precise prediction for the high temperature flow behaviors of AISI 4120 steel. The predictability of developed constitutive equation was further quantified in terms of correlation coefficient (R) and average absolute relative error (AARE). The R and AARE were found to be 0.9847 and 8.0372% respectively, which reflects the good prediction capabilities of the developed constitutive equation.