一种中碳高硅弹簧钢的热变形行为及流变应力模型

Hot deformation behavior and flow stress prediction model of a medium-carbon and high-silicon spring steel

利用MMS-200热模拟试验机对一种中碳高硅弹簧钢进行了单道次热压缩试验,研究了该钢在变形温度为900~1 100℃及应变速率为0.1~10 s^(-1)条件下的热变形行为,建立了应变补偿的Arrhenius流变应力预测模型。结果表明,应变速率和变形温度对该弹簧钢的奥氏体动态再结晶过程有显著影响。当变形速率为0.1、5、10 s^(-1)时,在所有变形温度下均发生奥氏体动态再结晶;当变形速率为1 s^(-1)且变形温度超过950℃时,奥氏体发生动态再结晶,其热变形激活能为445.5 kJ/mol。通过对真应力的预测值与试验值的对比,得出应变补偿Arrhenius模型具有准确性和预测性,其相关系数为0.976,平均相对误差为4.73%。

The hot deformation behavior of a medium-carbon and high-silicon spring steel was studied through isothermal hot compression tests based on MMS-200 thermomechanical simulator in the temperature range of 900-1 100 ℃ and at the strain rate of 0.1-10 s^(-1). The strain compensated Arrhenius model was established. The results show that the strain rate and deformation temperature have significant effects on the dynamic recrystallization. The dynamic recrystallization occurred at the strain rate of 0.1, 5, 10 s^(-1). At the strain rate of 1 s^(-1), dynamic recrystallization of the austenite gradually start when the deformation temperature exceeded 950 ℃. The hot deformation activation energy is estimated to be 445.5 kJ/mol. The reliability of the model is verified through a comparison between the predicted values from the model and the experimental data with an average correlation coefficient of 0.976 and an average relative error of 4.73%.