30Cr钢高温变形流变应力模型

Flow stress model for steel 30Cr during hot deformation

30Cr钢常用于大型阀体锻件,利用Gleeble-1500实验机对30Cr钢进行热模拟压缩实验,获得应变速率为0.1, 0.5, 2.5和10 s-1,变形温度为1000, 1050, 1100, 1150和1200 ℃,压缩变形量为60%条件下的30Cr钢的真应力-真应变曲线.实验结果表明,高温流变应力随着变形温度的增加和应变速率的降低而减小,在一定的变形条件下,呈现出典型的单峰型动态再结晶的应力-应变曲线特征.采用Arrhenius双曲正弦关系描述30Cr钢的高温流变行为,确定其热变形激活能,建立了30Cr钢的流变应力模型,其结果可为大型阀体模锻成形工艺的数值模拟和工艺参数的确定提供参考.

Steel 30Cr is used to forge the large valve. A set of hot compression experiment on steel 30Cr was conducted by Gleeble-1500 thermal-mechanical simulator,and the true stress-true strain curves were achieved with strain rates of 0.1,0.5,2.5 and 10 s-1,deform-ation temperatures of 1000,1050,1100,1150 and 1200℃ and deformation degree of 60%, respectively. The experimental results show that the flow stress at high temperature decreases with the increasing of deformation temperature and the decreasing of strain rate,and in the certain deformation conditions,the typical characteristics of true stress-true strain curves of dynamic recrystallization with single peak appears. Furthermore,the rheological behavior at hight temperature of steel 30Cr was described by the Arrhenius hyperbolic sine relation-ship,and the activation energy of hot deformation was confirmed. Finally,the flow stress model of steel 30Cr was established. The results can provide good reference for numerical simulation and determination of process parameters for die forging of large valve.