铸态AZ31B镁合金中厚板热轧制温度场数学模型

Mathematical Temperature Field Model about As-cast AZ31B Magnesium Alloy during Hot Rolling of Plate

采用Gleeble1500D热/力模拟试验机对铸态AZ31B镁合金圆柱试样在变形温度250~450℃、应变速率0.005~5s^(-1)下进行高温压缩试验,基于高精度流变应力模型,依托于刚塑性有限元分析软件针对镁板不同初轧温度、不同道次压下率以及不同轧制速度条件下的中厚板热轧制过程进行了热力耦合数值分析,利用数学解析的方法建立了不同工艺条件下镁板变形区域的温度场数学模型。结果表明,不同热轧工艺条件下轧制变形区域内温度的分布有很大区别,温度场数学模型需要划分不同工艺条件针对轧制后滑区和前滑区来分别建立;用简单数学方程来表征镁合金的传热过程,使得温度在线控制机理模型形式上更为简单,并且能够精确表征中厚规格镁板宽范围轧制条件下的传热机制。

High temperature compression tests of as-cast magnesium alloy AZ31 B cylindrical samples were preformed under the condition of deformation temperature 250-450 ℃and strain rate 0.005-5 s^-1 using Gleeble-1500 D thermal/mechanical simulation testing machine.Based on the high precision flow stress models and the rigid-plastic finite element analysis software,numerical analysis of coupled thermal-stress of hot rolling process of different initial rolling temperatures,different rolling reductions and different rolling speeds was also carried on.Under different conditions,models of temperature field of different magnesium plate deformation regions were established by mathematical analysis methods.The results show that under different conditions of hot rolling processes and rolling zones,regional distribution of rolling deformation temperature is so different that mathematical models of temperature field should be divided into different process conditions to establish.The mechanism of temperature controlled online is simple by mathematical equations to characterize the magnesium alloy heat transfer process and the heat transfer mechanism of magnesium plate rolling in wide ranges is accurately characterized.