07MnNiMoDR板轧制热变形本构方程

摘要：利用 Gleeble-3500 热模拟实验机完成了07MnNiMoDR钢热等温平面应变压缩实验，获得了温度 900～1100℃、应变速率 0.01～1s-1、变形率45%等条件的高温流变行为，其中温度和应变速率对流变应力的影响明显。基于对Arrhenius 方程和 Zener Hollomon 参数的解析，获得了热变形激活能Q，确定了峰值应力本构模型；通过分析应力应变与位错的关系，获得了硬化率及Z参数等与应力之间的内在关联性，建立了加工硬化 动态回复过程的流变应力模型；基于动态再结晶理论，采用Avrami模型计算了动态再结晶体积分数，获得Z参数计算方法，建立了动态再结晶过程的流变应力模型。利用所建立的本构模型完成了预测及对比分析，相关系数r为0.99，所建立的本构关系模型精度很高。

Constitutive equation for thermal deformation of 07MnNiMoDR plate in rolling

On the basis of isothermal thermal compression test of 07MnNiMoDR steel in a Gleeble 3500 thermal simulator, the high temperature rheological behavior of 07MnNiMoDR steel at the forming temperature of 900-1100℃, the strain rate of 0.01-10s-1 and the strain of 45% was discussed. The results show that the flow stress is significantly affected by deformation temperature and strain rate. By analyzing of Arrhenius hyperbolic sine equation and Zener Hollomon parameter, the peak rheological stress constitutive model was established, and the thermal deformation activation energy Q was calculated. Based on the stress dislocation relationship and dynamic recrystallization kinetics, the mechanism type constitutive models of the two stages of work hardening dynamic recovery and dynamic recrystallization were established, and the equation concerned with dynamic recovery coefficient, Zener Hollomon parameter and the dynamic recrystallization volume fraction were obtained. The change rule of rheological stress according to the established constitutive equation is agreed with that of the test. The experimental value is in good agreement with the prediction of the established constitutive equation for the correlation coefficient r of 0.99.