低合金钢Q345B动态再结晶动力学模型

采用Gleeble-3500热模拟实验机对低合金钢Q345B进行热压缩实验,研究其在变形温度为900～1100℃和应变速率为0.01～10s-1条件下的动态再结晶行为。结果表明:低合金钢Q345B在变形过程中存在动态再结晶现象,且随着温度的升高和应变速率的降低,临界应变越小,动态再结晶越易发生。根据流变应力、应变速率和变形温度的相关性,得到了动态再结晶激活能。通过对热模拟实验数据的分析计算,建立了峰值应变模型,动态再结晶临界应变模型和动态再结晶动力学模型。并对动态再结晶动力学模型进行了误差分析,证明了模型具有较高的精确性。最后,通过所建立的模型分析了变形条件对动态再结晶的影响,验证了实验所得出的在高温、低应变速率下更有利于动态再结晶发生的规律。

Dynamic recrystallization kinetics model of low-alloy steel Q345B

The dynamic recrystallization behavior of Q345B low-alloy steel during hot compression deformation was investigated at 900～1100 ℃ and strain rate of 0.01～10 s-1 on a Gleeble-3500 thermo-simulation machine.The results show that dynamic recrystallization during deformation occurs.As the deformation temperature increases and strain rate decreases,the critical strain and peak stress of dynamic recrystallization decrease,and softening caused by dynamic recrystallization is more obvious.According to the relevance of flow stress,strain rate and deformation temperature,the dynamic recrystallization activation energy is obtained.Peak strain model,dynamic recrystallization critical strain model and dynamic recrystallization kinetics model is set up through analyzing and calculating the data of thermo-simulation.The error analysis of dynamic recrystallization kinetics model proves that the model has good accuracy.Finally,the analysis of deformation conditions on the effects of dynamic recrystallization verifys the results deduced by experiments.