低碳钢高温变形行为及其本构方程的建立

Deformation Behavior and Constitutive Equation Establishment of Low Carbon Steel at High Temperature

采用热模拟试验机研究了QD08低碳钢在变形温度1 000~1 200℃和应变速率0.1~10s-1条件下的高温变形行为,得到了该钢的高温真应力-真应变曲线,分析了该钢在高温变形过程中的动态再结晶行为,并基于双曲正弦形式的Arrhenius方程建立了该钢的热变形本构方程。结果表明:在高温变形过程中,QD08低碳钢的峰值应力随变形温度的降低或应变速率的增大而增加;通过本构方程计算得到峰值应力的预测值与试验值相吻合,可以较好地描述QD08低碳钢的高温变形行为。

Deformation behavior of QD08 low carbon steel at high temperature was investigated by thermal simulator with strain rates of 0.1-10 s^（-1） at 1 000-1 200 ℃.The true stress-true strain curves of the low carbon steel at high temperature were obtained,the dynamic recrystallization behavior of QD08 low carbon steel was analyzed,and the constitutive equation of hot deformation was established based on the Arrhenius function with hyperbolic sine form.The results show that the peak stress increased with the decrease of deformation temperature or the increase of strain rate during deformation at high temperature.The predicted value of the peak stress calculated by the constitutive equation was in good agreement with the experimental results.The established constitutive equation could represent high temperature deformation behavior of QD08 low carbon steel.