AZ31B镁合金中厚板轧制热力耦合场数学模型

Mathematical Model of Coupled Thermal-Stress about AZ31B Magnesium Alloy Plate during Hot Rolling

采用Gleeble-1500D热力模拟试验机对铸态AZ31B镁合金圆柱试样进行了宽范围变形条件下的热压缩试验,拟合热压缩试验数据,针对镁合金应变软化特性建立了一种新的热力本构模型;依托于Deform-3D对镁板的实际热轧过程进行了热力仿真分析,依据轧制理论假设、宏观连续介质力学以及热力学原理,采用数学解析的方法建立了镁板热轧制区域中的应变、应变速率值分布模型以及三维温度场、应力场数学模型。研究结果表明:新建的热力本构模型预测精度较高,平均相对误差为5.1%;建立的轧制变形区域中的应变、应变速率值分布模型,温度场数学模型以及热力耦合场数学模型不仅形式简单易于为生产利用,更能精确表征中厚规格镁板热轧制过程中的热-力耦合变形机制。

In a wide range of deformation conditions, hot compression tests of AZ31 B magnesium alloy cast cylinder were carried out by Gleeble-1500 D thermal simulator. According to the strain softening characteristics of magnesium alloy, a new thermal deformation constitutive model was established. Relying on Deform-3D, the coupled thermal-stress simulation of hot rolling process of magnesium plate was analyzed. Based on the rolling theoretical assumptions, macroscopic continuum mechanics and thermodynamics, strain and strain rate value distribution models, three-dimensional temperature field and stress field mathematical models in rolling deformation zone were established by a mathematical analysis method. The results show that the new thermal constitutive model is in a higher accuracy and the average relative error is 5.1%. Strain distribution model, strain rate value distribution model, mathematical model of temperature field and mathematical model of stress field are concise in form and easy to be controlled online; furthermore, they could accurately characterize thermal-mechanical coupled deformation mechanism of hot rolling of magnesium plate.