论文部分内容阅读
通过考虑临界应变以后的软化机制,构建了包括动态回复和动态再结晶过程的金属热成形分段流变应力数学模型。利用Gleeble3500热模拟试验机进行了X70HD抗大变形管线钢低应变速率到高应变速率下的单道次热压缩实验,获得了应力-应变曲线,并确定了基于Z参数的特征点、待定参数值,验证了模型不但在低应变速率下适用,在高应变速率下仍具备较高的准确性;建立了从动态再结晶开始到完成整个过程被考虑在内的再结晶动力学模型,通过与基于Johnson-Mehl-Avrami(JMA)方程求得的动态再结晶实际体积分数相比较,表明该动力学模型具有很高的精确度,可为抗大变形管线钢生产中的组织、性能预报提供理论依据。
By considering the softening mechanism after critical strain, a mathematical model of thermoforming segmented flow stress, including dynamic recovery and dynamic recrystallization, was constructed. A single pass thermal compression experiment was carried out at low strain rate to high strain rate of X70HD large deformation pipeline steel with Gleeble3500 thermal simulation tester. The stress-strain curve was obtained and the characteristic points based on Z parameter were determined. The parameters to be determined , The model is validated not only at low strain rates but also at high strain rates. A recrystallization kinetic model is established from the beginning of dynamic recrystallization to the completion of the whole process. Johnson-Mehl-Avrami (JMA) equation to compare the dynamic recrystallization actual volume fraction shows that the kinetic model has a high accuracy, which can provide theoretical basis for the prediction of microstructure and properties in the production of large deformation pipeline steel .