45钢低温区热变形行为研究

 利用Gleeble-1500热模拟试验机研究了不同变形条件对45钢低温区热变形行为的影响。试验结果表明：峰值应力随变形温度的降低和应变速率的提高而增大；当应变速率ε]≥0.01s-1、变形温度 t]＜500 ℃时，发生动态回复；当应变速率ε]≤1s-1、变形温度t]≥500 ℃时，发生动态再结晶。在Sellars -Tegart方程的基础上，建立了45钢低温区加工硬化-动态回复、动态再结晶2阶段流变应力模型；根据试验结果计算拟合了模型中各参数。采用建立的流变应力模型成功预测了动态回复、动态再结晶型应力-应变曲线。利用上述模型对45钢中厚板轧后低温工业热矫直的矫直力进行了预测，其结果与实测值吻合良好。

Research on Hot Deformation Behavior of 45 Steel in Low Temperature Region

The effect of different deformation conditions on the deformation behavior of 45 carbon structural steel at low temperatures was studied using Gleeble-1500 thermal-simulation machine. Experimental results show that peak stress increased with the decreasing of deformation temperature and the increasing of strain rate; dynamical recovery occurred when strain rate ε]≥0.01 s-1, and deformation temperature t]＜500 ℃; dynamical recrystallization occurred when strain rate ε]≤1 s-1, and deformation temperature t]≥500 ℃. The flow stress models at work harding-dynamical recovery stage and dynamical recrystallization stage were both established based on the Sellars-Tegart equation. The parameters in these models were fitted according to the experimental results. The stress-stain curves of both dynamic recovery style and dynamic recrystallization style were successfully predicted. The straightening force at low temperature of 45 steel plates in the industrial trial was predicted, and the results matched well with the measured values.