Constitutive equations describing the flow stress of Q235 steel undergoing hot plastic deformation have been developed by integrating the microstructure models and exponential flow stress models presented in literatures, in which the microstructure models parameters have been re-determined based on the related experiments carried out on cylindrical specimens of the Q235 steel. Therefore, the integrated constitutive equations are capable of calculating the evolution of austenite grain size and investigating the effects of average austenite grain size on the flow stress of Q235 steel during hot deformation. A three-dimensional thermo-mechanically coupled FEM simulation of an 11-pass H-shape metal roughing rolling process with the austenite grain size evolution taken into account have been carried out to verify the rationality of roll pass schedule. The accuracy of the integrated constitutive equations has been preliminary validated by the comparisons between measured and the calculated values of rolling force.

中文翻译：

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多道次金属热轧过程中平均奥氏体晶粒尺寸演变模拟

结合文献中提出的微观结构模型和指数流应力模型，建立了描述Q235钢热塑性变形的本构方程，并根据在圆柱体上进行的相关实验重新确定了微观结构模型参数。 Q235钢的样品。因此，综合本构方程能够计算出奥氏体晶粒尺寸的演变，并能够研究平均奥氏体晶粒尺寸对Q235钢热变形过程中流动应力的影响。对11道次H形金属粗轧过程进行了三维热力耦合有限元模拟，并考虑了奥氏体晶粒尺寸的演变，以验证道次轧制计划的合理性。