Study on Dynamic Recrystallization Models of 21-4N Heat Resistant Steel

The high-temperature deformation process and dynamic recrystallization (DRX) process of 21-4N were investigated under the conditions of the deformation temperature range of 1273~1453K, the strain rate range of 0.01~10s-1 and the deformation degree of 60% (the total deformation is 0.916) by using Gleeble-1500D thermal simulated test machine. The curves of stress-strain (σ – ε) were obtained, and the curves of work hardening rate (θ) and strain (ε) were obtained by taking derivative of σ – ε. The DRX critical strains under different conditions were determined by the curves of work hardening rate (θ – ε), and the DRX critical strain model was established. The peak strains of 21-4N were obtained by the curves of σ – ε, the relationship between peak stress (σp) and critical strain (εc) was determined, and the peak strain model was established. The DRX volume fraction models of 21-4N were established by using Avrami equation. The DRX grain size of 21-4N was calculated by Image Pro Plus 6.0, and its DRX grain size models were established.