300M高强钢高温流变行为及本构方程

摘要

通过Gleeble 3500高温热模拟压缩实验,研究300M高强钢在变形温度900～1 150℃、应变速率0.01～10 s-1条件下变形温度和应变速率对材料流动应力的影响规律,建立高温热变形材料本构方程.研究结果表明:变形温度和应变速率对300M钢材料流变应力都有显著的影响,随着变形温度的降低和应变速率的增加,材料流动应力增加;建立了材料常数α,n,ln A和激活能Q与真应变之间的非线性四项式函数关系;所建立材料本构方程预测值与实验值具有较好的一致性,说明该本构方程能够准确地描述300M钢热变形条件下的材料流变行为.%In order to study the effect of deformation temperature and strain rate on the flow stress of 300M high strength steel,isothermal hot compression was tested by Gleeble 3500 thermal simulation machine under environment with temperatures varying from 900 to 1 150 ℃ and strain rates ranging from 0.01 to 10 s-1.The constitutive equation of 300M steel was established on the empirical models.The results show that deformation temperature and strain rate have a significant influence on the flow stress behavior of 300M steel.The material flow stress increases with the decreases of deformation temperature and the increase of strain rate.A nonlinear quadrinomial function is proposed to define the relationship between material constants α,n,ln A and activation energy Q and strain.The predicted flow stress values using the proposed constitutive equation have a good agreement with the experimental values,which illustrates that the established constitutive equation can accurately describe the rheological behavior of 300M steel on deformation conditions.