Si含量对高硅电工钢热变形与动态再结晶行为的影响

采用Gleeble-3800D热模拟试验机在应变量0.6、变形温度750~1050℃、应变速率0.01~1 s-1工艺条件范围内, 研究了Fe-(5.5%、6.0%、6.5%) Si高硅电工钢的热变形与动态再结晶行为.采用线性回归方法, 建立了三种成分实验钢的流变应力本构方程.计算得到Fe-5.5% Si、Fe-6.0% Si和Fe-6.5% Si高硅电工钢的热变形激活能分别为310.425、363.831和422.162 kJ·mol-1, 说明Fe-(5.5%、6.0%、6.5%) Si高硅电工钢的热变形激活能随Si质量分数的增加而增大, 这使得Fe-(5.5%、6.0%、6.5%) Si高硅电工钢相同条件下的变形抗力随Si含量的升高而增大.采用金相截线法对不同成分和变形条件下实验钢的动态再结晶百分数进行了统计, 结果表明: 同一热变形条件下, Fe-(5.5%、6.0%、6.5%) Si高硅电工钢的动态再结晶百分数随Si质量分数的升高而减小.本文实验条件下, 当变形温度为750~850℃时, Fe-(5.5%、6.0%、6.5%) Si高硅电工钢软化机制主要为动态回复; 而变形温度为950~1050℃时, Fe-(5.5%、6.0%、6.5%) Si高硅电工钢软化机制主要为动态再结晶. 

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.