Hot Deformation Behavior of DT4 Pure Iron in the Austenite Single-Phase Region: Experiment and Finite Element Simulation

The control of grain size and uniformity during the rolling process of DT4 electromagnetic pure iron is critical for its coercive force. Dynamic recrystallization during hot processing is closely related to grain size and uniformity control; therefore, the study of hot deformation and dynamic recrystallization process of DT4 in the γ-phase region is essential. A 60% hot deformation of DT4 is conducted at temperatures of 950, 1000, and 1050 °C, respectively, with strain rates ranging from 0.01 to 10 s⁻¹. The results indicate that in the γ-phase region, after hot compression, the grain size and recrystallization fraction of DT4 decrease as the strain rate increases and the temperature decreases. A constitutive model and dynamic recrystallization model for DT4 are established, which can be used to predict the flow stress, recrystallization fraction, grain size, and critical strain of DT4, based on deformation temperature, strain rate, and strain. The dynamic recrystallization model is integrated into the Deform-3D to simulate the critical strain during the hot deformation process of DT4. According to the correlation coefficient (R) and root mean square error results, the simulated data are consistent with the experimental data.