PH13-8Mo钢热变形行为及本构模型

Hot deformation behavior and constitutive model for PH13-8Mo steel

利用Gleeble-1500热模拟机对PH13-8Mo钢进行不同参数下的热压缩试验,研究变形温度为850~1030℃,应变速率为0.1~10 s^(-1)条件下试验钢的热变形行为。结果表明,PH13-8Mo钢热压缩变形过程中流变应力呈现先上升、后平缓最后继续上升的特征,动态回复和动态再结晶行为导致热变形过程中出现软化现象,较高的变形温度有助于动态再结晶发生,PH13-8Mo钢晶粒尺寸对温度的敏感性较高。基于试验结果,通过周纪华-管克智模型建立了PH13-8Mo钢热变形本构模型,能够反映试验钢热变形过程中真应力-真应变的变化规律,预测相关系数为0.965,均方差为20.9。借助模拟仿真分析验证,证实该模型对PH13-8Mo钢热加工工艺的合理选择提供了一定的理论参考。

The hot compression test under different parameters of PH13-8 Mo steel was conducted by Gleeble-1500 thermo-mechanical simulator.The hot deformation behaviors of test steel were studied at the deformation temperatures of 850-1030℃ and the strain rates of 0.1-10 s^(-1).The results show that the flow stress of PH13-8 Mo steel increases first,and then falls into a stable stage and finally increases again in the hot compression deformation process.Dynamic recovery and recrystallization behaviors lead to the soften phenomenon in the hot deformation process,and higher deformation temperature contributes to the occurrence of dynamic recrystallization.There is a high temperature sensitivity with the grain sizes of PH13-8 Mo steel.The hot deformation constitutive model of PH13-8 Mo steel was built based on Z-G model and test results,which can reflect the true stress-true strain change laws of test steel in the hot deformation process.The related coefficient was 0.965 and the root mean square error was 20.9 in the predction.According to the simulation analysis and verification,the Z-G model provides theoretical reference for the selection of hot deformation process for PH13-8 Mo steel.