AZ31镁合金板材轧制边裂深度预判模型研究

Study on Prediction Model of Edge Crack Depth of Rolled AZ31 Magnesium Alloy Sheet

摘要:

本研究在400℃温度下，分别以压下量10%，15%，20%，25%，30%，35%，40%和45%对初始厚度为7mm的AZ31镁合金板材进行了轧制过程数值模拟以及实验验证研究，并观察轧制后的显微组织。研究结果表明，在当前轧制条件下，当单道次压下量达到20%时，板材边部将有裂纹萌生，并且边部裂纹深度随着压下量的增大而不断增大，由20%时5240μm的边部裂纹深度增加到压下量45%的14056μm；根据数值模拟结果，得到了沿板宽方向的损伤值分布情况，建立了边部裂纹深度预判模型；对于裂纹深度，轧制实验实测值和所建立的裂纹深度预判模型的计算值之间的平均误差为9.23%; SEM观察结果表明边部裂纹附近的显微组织中含有大量孪晶。

Abstract:

In this study, the numerical simulation of rolling process and experimental verification was carried out at 400℃ temperature of as-cast the AZ31 magnesium alloy sheet with initial thickness of 7mm. The reduction was 10%, 15%, 20%, 25%, 30%, 35%, 40% and 45%, respectively. Microstructure and edge crack were analyzed after rolling. The results show that the edge crack was occurred when the single pass reduction up to 20%. The edge crack depth has increased from 5.04mm of 20% reduction to 14.05mm of 45% in current rolling condition. According to numerical simulation results, the damage distribution along the width of the plate was obtained. And we have established the prediction model of edge crack depth. For the edge crack depth, the average error between the actual measured data and the calculated value by the prediction model is 9.23%. The SEM observation results show that the microstructure near the edge crack contain a large number of twins.