Effect of Si content on hot deformation behavior and dynamic recrystallization of high silicon electrical steel

High-silicon electrical steel is an excellent soft magnetic material with high permeability, low coercive force, and nearzero magnetostriction coefficient. Compared with other preparation methods of high-silicon electrical steel sheet, the rolling method has the advantages of short process and high efficiency. Among the rolling methods, hot rolling is one of the most important part in the formation of high-silicon electrical steel sheet. Therefore, it is very important to study the hot deformation and dynamic recrystallization behaviors of high-silicon electrical steels. In this study, hot deformation and dynamic recrystallization behaviors of Fe-(5.5%, 6.0%, 6.5%) Si high-silicon electrical steel were studied using a Gleeble-3800D thermal-mechanical simulator with a deformation temperature of 750-1050℃ and strain rate of 0.01-1 s^-1. The constitutive equations of Fe-(5.5%, 6.0%, 6.5%) Si high-silicon electrical steels were established by linear regression analysis. The thermal deformation activation energies of Fe-5.5% Si, Fe-6.0% Si, and Fe-6.5% Si high-silicon electrical steel are 310.425, 363.831, and 422.162 kJ·mol^-1, respectively. It is observed that the thermal deformation activation energies of Fe-(5.5%, 6.0%, 6.5%) Si high-silicon electrical steel improve with the increase of Si content, which makes the deformation resistance of Fe-(5.5%, 6.0%, 6.5%) Si high-silicon electrical steel improve with the increase of Si content. Moreover, the dynamic recrystallization percentage was calculated using the intercept method of metallographic examination, and the statistical results show that the dynamic recrystallization percentage of Fe-(5.5%, 6.0%, 6.5%) Si high-silicon electrical steel decreases with the increase of Si content under the same deformation condition. Meanwhile, at the temperature of 750-850℃, the softening mechanism of Fe-(5.5%, 6.0%, 6.5%) Si high-silicon electrical steel is mainly dynamic recovery, while at the temperature of 950-1050℃, the softening mechanism is mainly dynamic recrystallization.