Mathematical Modeling of Critical Condition for Dynamic Recrystallization

A new model is presented to describe the flow stress up to the peak of the stress-strain curves firstly. And then utilizing the second derivative of work hardening rate with respect to stress, an equation is derived to calculate the critical strain for the onset of dynamic recrystallization. Finally, the developed model is used to predict the stress-strain curves of X12 ultra-super- critical rotor steel and determine the critical strain for the onset of dynamic recrystallization under different hot deformation conditions. Results show a good agreement between the predicted and the experimental results with a high level of accuracy.