The kinetics and cellular automaton modeling of dynamic recrystallization behavior of a medium carbon Cr-Ni-Mo alloyed steel in hot working process

The dynamic recrystallization (DRX) behavior of a medium carbon Cr-Ni-Mo alloyed steel 34CrNiMo was studied in the wide temperature range of 900-1150 °C and the strain rate of 0.002-5 s−1. Based on relations between the strain hardening rate and stress, the characteristic points, including critical strain (εc), critical stress (σc), peak strain (εp), peak stress (σp), were determined from the strain rate hardening versus stress curves. The Avrami equation was developed to model the kinetics of DRX, whereas the characteristic points can be expressed as a function of Zener-Hollomon parameter. Then the austenite grain size of DRX was measured by metallography and found to be a power law function of Zener-Hollomon parameter with an exponent of −0.2013. Besides, a mesoscopic cellular automaton model has been established to simulate the austenite DRX for the tested steel. This model was verified by means of the kinetics and topology of DRX.