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利用Gleeble-1500热模拟试验机对10Cr12Ni3Mo2VN钢进行压缩实验,研究了变形温度为850~1200℃,应变速率为0.01~10 s-1条件下的热变形行为.结果表明,随变形温度升高和应变速率降低,再结晶晶粒尺寸增加.变形温度1200℃,经60%压缩变形后,应变速率较高时再结晶晶粒呈等轴状,应变速率较低时出现混晶.通过传统直线拟合方法和LevenbergMarquardt算法分别建立了热变形双曲正弦本构方程,2种方法建立的本构方程均具有较高预测精度.采用Levenberg-Marquardt算法可以一次性求解所有材料参数,求解步骤简单,结果可信.利用加工硬化率-应力(q-s)曲线,通过二次求导,准确测得临界应变,并建立了临界应变、峰值应变与Zener-Hollomon因子(Z因子)之间的关系方程.
The hot deformation behavior of 10Cr12Ni3Mo2VN steel was investigated by using Gleeble-1500 thermal simulator, and the deformation behavior was studied at deformation temperature of 850-1200 ℃ and strain rate of 0.01-10 s-1. The results show that with the increase of deformation temperature and The strain rate decreases and the grain size of recrystallized grains increases.The deformation recrystallization temperature is 1200 ℃ and 60% compressive deformation, the recrystallized grains are equiaxed at higher strain rate and mixed crystals appear at lower strain rate. The combined method and the Levenberg-Marquardt algorithm respectively establish the hyperbolic sine constitutive equations of thermal deformation, and the constitutive equations established by the two methods all have higher prediction accuracy. All material parameters can be solved all at once with the Levenberg-Marquardt algorithm, and the solving steps are simple. The results Credible.Using the hardening rate-stress (qs) curve, the critical strain can be accurately measured by quadratic derivation, and the relationship equation between critical strain, peak strain and Zener-Hollomon factor (Z factor) has been established.