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利用Gleeble-1500热模拟实验机进行压缩实验,研究了KT5331钢变形温度为850~1200℃,应变速率为0.01~12 s-1条件下的热变形行为。结果表明,随变形温度升高、应变速率降低,动态再结晶越容易发生,再结晶晶粒尺寸增加,完全动态再结晶温度约为1100℃。完全动态再结晶温度以下,随变形温度升高和应变速率降低,动态再结晶晶粒体积分数增加;完全动态再结晶温度以上,在低应变速率下,经60%压缩变形后,出现混晶形貌,应变速率较高时为等轴晶。通过拟合得到热变形激活能Q为436.541 k J/mol,建立了热变形双曲正弦本构方程,εexp(436541/RT)=6.12×101 5[sinh(0.009344σp)]4.739,具有较高预测精度,根据模型计算所得预测值与实验值之间的平均相对误差为5.9%。
The compression experiments were carried out on a Gleeble-1500 thermal simulator to study the thermal deformation behavior of KT5331 steel at 850-1200 ℃ and strain rate of 0.01-12 s-1. The results show that as the deformation temperature increases, the strain rate decreases and the dynamic recrystallization occurs more easily. The recrystallized grain size increases and the complete dynamic recrystallization temperature is about 1100 ℃. Under the completely dynamic recrystallization temperature, with the increase of deformation temperature and strain rate, the volume fraction of dynamic recrystallization grain increases. When the recrystallization temperature is above 60 ℃, the mixed crystal is formed at low strain rate Appearance, higher strain rate equiaxed. The thermal deformation activation energy, Q, is 436.541 kJ / mol. The hyperbolic sine constitutive equation for thermal deformation is established, and εexp (436541 / RT) = 6.12 × 101 5 [sinh (0.009344σp)] 4.739. High prediction accuracy, the average relative error between the predicted and experimental values calculated from the model is 5.9%.