30Cr4MoNiV超高强度钢热变形本构方程的构建与优化

Construction and Optimization of Hot Deformation Constitutive Equation of 30Cr4MoNiV Ultra-high-strength Steel

采用Gleeble-3500热模拟机在温度为1173~1373 K和应变速率为0.01~10 s^(-1)的条件下通过热压缩试验研究了30Cr4MoNiV超高强度钢的热变形行为,引入应变补偿建立了优化的本构方程。结果表明:流动应力随应变速率的增大和变形温度的降低而增大。采用幂律函数、指数函数和双曲正弦函数构建的三种本构方程中,双曲正弦函数的准确度最高。基于双曲正弦函数并引入应变补偿优化后的本构方程可以较为准确地预测30Cr4MoNiV超高强度钢在热加工过程中的流动应力。

In this work,the hot deformation behavior of 30Cr4MoNiV ultra-high-strength(UHS)steel is investigated by isothermal compression tests using the Gleeble-3500 thermal simulation machine at 1173-1373 K under the strain rate of 0.01-10 s^(-1),and the optimized constitutive equation with strain-dependent constants suitable for 30Cr4MoNiV UHS steel is established.The results show that the flow stress increases with the increase of the strain rate and the decrease of the deformation temperature.The constitutive equation constructed by hyperbolic sine function has the highest accuracy among the three constitutive equations constructed by power law function,exponential function and hyperbolic sine function.Based on the hyperbolic sine function and the strain-dependent constants,the optimized constitutive equation can accurately predict the flow stress of 30Cr4MoNiV UHS steel in the process of hot processing.