Effect of V content on the hot deformation behavior and dynamic recrystallization of high-strength steel

Hot compression tests were conducted on two high-strength steels containing different V contents (0.17 wt% and 0.44 wt%) at 950–1150 °C and strain rates of 0.01–10 s −1 . Based on the friction-corrected true stress–true strain curves, a strain-compensated Arrhenius constitutive model was established, and processing maps were constructed at a true strain of 0.7. Combined with EBSD characterization of the quenched microstructures after hot compression, the dynamic softening behavior, dynamic recrystallization (DRX), and precipitation behavior of the two steels during hot deformation were systematically analyzed. The results show that the flow stress of both steels decreases with increasing deformation temperature and increases with increasing strain rate. Compared with the 0.17V steel, the 0.44V steel exhibits a higher peak stress and a larger apparent activation energy for hot deformation under the same conditions, indicating a greater resistance to hot deformation. The 0.17V steel exhibits a wider stable hot-working window, whereas the stable domain of the 0.44V steel shifts toward the higher-temperature side and the processing window becomes markedly narrower. EBSD and PAG/GOS-based analyses suggest that, under the typical condition of 1050 °C/0.1 s −1 , DRX-related microstructural reconstruction occurred to different extents in the two steels. The 0.17V steel exhibited a lower degree of local orientation distortion and more sufficient microstructural restoration, whereas the 0.44V steel retained more pronounced orientation gradients and deformation substructures. In contrast to the 0.17V steel, V-rich precipitates are observed in the 0.44V steel, indicating that in the higher-V steel, precipitates together with defect structures increase the resistance to interface migration, thereby suppressing DRX. Overall, a moderate V content is more favorable for obtaining a wider hot-processing window and a more adequate dynamically softened microstructure, whereas a higher V content increases deformation resistance, promotes precipitation-related hindrance, and delays DRX evolution.