Q345B钢动态再结晶动力学模型研究

Study of dynamic recrystallization of Q345B steel

在Gleeble 1500热模拟机上进行Q345B钢单道次压缩变形实验,得到其真应力-真应变曲线,结合加工硬化率曲线,确定了Q345B钢动态再结晶临界应变εC、峰值应变εP和稳态应变εS。根据实验结果得到Zener-Hollomon方程和动态再结晶状态图,利用Johnson-Mehl-Avrami(JMA)方程法得到再结晶体积分数实际值,采用3种不同的再结晶体积分数预报模型对实验数据进行回归,并对再结晶体积分数实测值和预报值进行对比。结果表明,Epsilon-S/Epsilon-C模型精度最高,Epsilon-S模型精度次之,Epsilon-P模型精度最差。

Single-pass compression deformation tests of Q345B steel were conducted on Gleeble 1500 hot simulator. Deformation values of the steel including critical strain, peak strain and steady strain were obtained according to the stain-stress data and work hardening data. The Zener-Hollomon pa- rameter equation was given and status diagram of dynamic recrystallization （DXR） was plotted. Then measured DXR values were calculated by the method of Johnson-Mehl-Avrami （JMA）. Three differ- ent DXR models were fitted with test data, and it is shown by the comparison of measured and predic- ted DXR values that the model considering steady and critical strain has the highest accuracy.