Hot Deformation Behavior and Dynamic Recrystallization Characteristics in a Low-Alloy High-Strength Ni-Cr-Mo-V Steel

This study presented a quantitative investigation of deformation behavior and dynamic recrystallization of low-alloy high-strength Ni-Cr-Mo-V steels during hot deformation. A series of isothermal compression experiments were performed at temperatures ranging from 800 to 1200 degrees C and strain rates from 0.01 to 10 s(-1) with a height reduction of 60%. A complete Arrhenius constitutive model and processing maps were developed. The results showed that the constitutive model had the ability to predict the flow stress with an average absolute relative error of < 5.7%. The processing maps constructed at strains of 0.2, 0.4, and 0.8 showed that flow instability was prone to occur at higher strain. Dynamic recrystallization tended to take place at higher temperatures (900-1200 degrees C) and lower strain rates (0.01-1 s(-1)). The critical strain for the onset of dynamic recrystallization was determined, and a kinetics model was developed. The predicted results for recrystallization volume fraction and flow stress were compared with the experimental data, which indicated that the model was accurate and reliable.