Hot Deformation Behavior and Processing Map of 25Cr2Ni2MoV Steel

This study investigates the hot deformation behavior of electroslag remelted (ESR) 25Cr2Ni2MoV steel, focusing on the effects of deformation temperature and strain rate on flow stress, microstructure evolution, and dynamic recrystallization (DRX) mechanisms. Hot compression tests were performed at temperatures ranging from 1120 °C to 1210 °C and strain rates from 0.01 s−1 to 10 s−1 to generate true stress–strain curves. The friction and adiabatic temperature effects were corrected to ensure accurate results. The data reveal that the material exhibits a single-peak true stress–strain curve, characteristic of dynamic recrystallization softening. The flow stress is negatively sensitive to temperature and positively sensitive to strain rate. An Arrhenius-type constitutive model was developed, and the activation energy for hot deformation was determined to be 371.3 kJ/mol. EBSD analysis show that the recrystallized grain size is highly dependent on strain rate, with finer grains formed at lower strain rates (0.01–0.1 s−1). A processing map constructed at a true strain of 0.5 identified an optimal hot-working window at deformation temperatures of 1160–1200 °C with strain rates below 0.37 s−1, providing guidance for the forging process of large 25Cr2Ni2MoV steel.