| The high temperature deformation behaviors of the V-microalloyed steel were studied by hot torsion test at temperatures from 900 to 1050℃ and in the range of strain rate from 2.0 sec^(-1) to 2.0×10^(-2) sec^(-1). Within the experimental range, this steel exhibited typical dynamic recrystallization shapes of the flow curve. The dynamic recrystallization behaviors were analyzed with changing of deformation conditions from single to multiple peak deformation, and the metallographic observations on the two types flow curves revealed that the single peak flow curves were associated with grains refinement and the multiple peak flow curves were associated with grains coarsening. The sizes of the dynamically recrystallized grains were also measured, and they were able to be parameter as a function of the Zener-Hollomon presented, Z without exhibiting any dependence on the initial grain sizes. The constitutive equation for hot deformation of this steel, relating the flow stresses to the strain rate and temperature, could be described by power law, ε´= Aσ^n´_p exp(-Q/RT). |
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