基于动态再结晶37CrS4特种钢的流变应力预测模型

使用Gleeble-1500D热模拟实验机对37CrS4特种钢进行单道次热压缩实验，研究了37CrS4钢在950~1100℃和0.01 s^-1~10 s^-1条件下的热压缩流变应力行为。结果表明：这种钢的真应力应变曲线出现了明显的高温塑性变形动态再结晶行为；热变形后的微观组织为典型的板条状马氏体，发生动态再结晶行为的临界应变值与峰值应变比值为0.77162，拟合相关性R²=0.9576；其软化机制为动态回复与动态再结晶的共同作用。引入Zener-Hollomon参数(Z参数)建立再结晶动力学模型，得到了37CrS4特种钢基于动态回复、动态再结晶的分段式流变应力本构模型。本构模型的平均相关性R²=0.9756，分段式本构模型的预测应力与实验应力具有较高的一致性，能较为准确的预测37CrS4高温塑性变形时流变应力的变化。

Flow Stress Prediction Model of 37CrS4 Special Steel Based on Dynamic Recrystallization

The flow stress behavior during hot compression of 37CrS4 at 950~1100℃, by strain rate in the range of 0.01 s^-1~10 s^-1 was investigated by means of single pass hot compression test with Gleeble-1500D thermal simulation machine. The results show that the true stress-strain curve of 37CrS4 special steel presents the occurrence of obvious dynamic recrystallization during high-temperature plastic deformation. The microstructure after hot deformation is typical lath martensite. The ratio of critical strain to peak strain of dynamic recrystallization behavior is 0.77162, and the fitting correlation is 0.9576. The softening mechanism of the material is the synergistic effect of dynamic recovery and dynamic recrystallization. The zener-Hollomon parameter (Z parameter) was introduced to establish the recrystallization kinetic model, and then the segmented flow stress constitutive model of 37CrS4 special steel based on dynamic recovery and dynamic recrystallization was obtained. The average correlation of the constitutive model is 0.9756. The predicted stress of the segmented constitutive model was consistent with the experimental stress, in fact, which could accurately predict the high temperature plasticity of 37CrS4 and the variation of flow stress during deformation.