Fe-6.5％Si钢中温变形过程本构方程

利用Gleeble 3500开展了Fe-6.5%Si(质量分数)钢在变形温度300，400，500，600℃及应变速率为0.05，0.5，5s^-1条件下的单道次压缩实验.在初始均匀塑性变形阶段，加工硬化作用使流动应力迅速增加，随着变形继续动态软化机制启动，流动应力增加量减弱.随着温度升高和应变速率降低，应变硬化指数减小.提出了通过变形温度、应变速率描述应变硬化指数的方法构建Fe-6.5%Si钢中温变形过程本构方程.构建的本构方程对不同变形条件的应力预测结果和实测值吻合良好，平均相对误差约为5.35%，预测精度较高.

Constitutive Equations for Moderate-Temperature Deformation of Fe-6.5%Si Steel

Using Gleeble 3500， the deformation behaviors of a single-pass compression for Fe-6.5%Si steel at temperature ranging from 300 to 600℃ and strain rate ranging from 0.05 to 5s^-1 were studied. The flow stress increases dramatically at initial uniform plastic deformation stage due to work hardening， while the increment of flow stress is to be weakened during further deformation when the dynamic softening occurs. The strain hardening index decreases with increasing the temperature and decreasing the strain rate. A new constitutive model of Fe-6.5%Si steel at moderate-temperature deformation was proposed through describing the strain hardening index as the function of temperature and strain rate. The results predicted by this model are in good agreement with the experimental data， with an average relative error about 5.35%.