Effect of Vanadium on the Hot Deformation Behavior of Vanadium-Microalloyed Steel for Thin Slab Direct Rolling

Abstract

The effects of V on hot deformation properties of low-carbon steel were investigated in the temperature range of 1173 K to 1473 K (900 A degrees C to 1200 A degrees C) and for strain rates from 0.1 to 5 s(-1) for compositions with a V content in the range of 0 to 0.125 wt pct. The critical stress and strain for dynamic recrystallization (DRX) initiation were obtained from the stress dependence of the strain hardening rate. The hot deformation properties of V-alloyed steel were studied in function of the temperature-corrected strain rate. The experimental results were used to construct a kinetic model of DRX. V was found to have no influence on the hot deformation properties for V contents less than 0.125 pct, indicating the absence of both solute drag and precipitation effects at low V content. When the V content reached 0.125 wt pct, the activation energy for DRX increased and DRX was suppressed in high strain rate condition.