Flow stress prediction at hot working conditions

The hot flow stress of 17-4 PH stainless steel was modeled using the constitutive equations. The hyperbolic sine equation with strain dependent constants for compensation of strain was found to be inappropriate for flow stress modeling and prediction. A new formula has been developed for the prediction of DRX flow curve in a simple form with the peak stress, peak strain, and four constants. These constants can be determined by nonlinear regression of one or more experimental flow curves. The calculated constants are essentially independent of deformation conditions. The flow curves obtained by this model were in a very good agreement with experimental results. The generalization ability of the proposed equation proved the applicability of this method for predicting the flow stress at unseen deformation conditions.