Abstract
Low carbon steel and vanadium-microalloyed steel were deformed by torsion in the temperature range from 900° to 1 200°C and the strain rate range about 10-3 to 10s-1.
A characteristic type of deformation with dynamic recrystallization, which has either single or multiple peaks in the stress-strain curve, was observed in both steels under all the experimental conditions. The dynamic recrystallization behavior was analyzed with a special emphasis on the transition from multiple to single peak deformation. The size of the dynamically recrystallized grain was also measured. It was able to be presented as a function of ZENER-HOLLOMON parameter, Z, and it did not exhibit any dependences on the initial grain size.
The condition for transition of the deformation behavior was investigated in detail from the following two view points (i) effect of the relative magnitude of the critical strains for recrystallization on the transition behavior, and (ii) effect of the initial grain size on the transition.
