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通过20MnNiMo钢多组试样的热压缩实验获得应变速率为0.01～10 s-1、变形温度为1173～1473 K条件下的真应力-应变数据。结合Arrhenius双曲正弦本构方程,通过线性回归分析求解得到不同变形条件下本构模型中的热变形激活能Q,材料常数n、α及结构因子A,从而构建了用于表征20MnNiMo钢流变应力与应变量、温度、应变速率之间内在关系的本构方程。研究结果表明:20MnNiMo钢在热压缩变形过程中发生了明显的动态软化行为,流变应力水平随应变速率的增加而增加,随温度的升高而降低;流变应力的预测值与实验值较吻合,而且预测的最大相对误差仅为7.54%。
The true stress-strain data of strain rate of 0.01 ~ 10 s-1 and deformation temperature of 1173 ~ 1473 K were obtained by thermal compression experiments of 20MnNiMo steel samples. Combined with the Arrhenius hyperbolic sine constitutive equation, the thermal deformation activation energy Q, the material constants n, α and the structural factor A in the constitutive model were solved by linear regression analysis, and the results of the rheological properties of 20MnNiMo Constitutive equations of the intrinsic relationship between stress and strain, temperature, and strain rate. The results show that the dynamic softening behavior of 20MnNiMo steel during hot compression deformation is obvious. The flow stress level increases with the increase of strain rate and decreases with the increase of temperature. The predicted value of flow stress and the experimental value Coincide, and the maximum relative error predicted is only 7.54%.