Prediction of flow stress curves based on characteristic points

Abstract

It is well known that work hardening, dynamic recovery, dynamic recrystallization, and recrystallization in a steady state will occur in materials during hot working process, which can be reflected on flow stress curves. Especially, characteristic points can be designated on the flow stress curves, such as the critical point for the onset of dynamic recrystallization, peak point, and the point where a steady state is reached. There is a close relationship between the characteristic points and flow behaviors of materials. So, it is hard to achieve a flow stress model with high precision without considering the characteristic points. In the present research, uni-axial compression tests were performed on a high-strength low-alloy steel and the flow behaviors of the tested steel were analyzed. Based on the characteristic points resulting from the flow stress curves, a piecewise function has been developed for the prediction of the flow stress curves of the tested steel. The proposed model was validated by comparing the predictions and the experimental data. It was found that the flow stress curves resulting from this model were in a very good agreement with the experimental ones. This model can predict the flow stress of the material with high precision.

Graphical abstract