AZ31镁合金板材等径角轧制-单道次弯曲变形工艺有限元分析

Finite Element Analysis of AZ31 Magnesium Alloy Sheet in the Equal Channel Angle Rolling-Single Pass Bending Deformation Process

【目的】镁合金在室温下塑性差、基面织构强烈,这极大地限制了它的应用。因此,改善镁合金的室温塑性、优化镁合金基面织构十分重要。【方法】课题组在多级连续剪切-弯曲工艺的基础上,设计出等径角轧制-单道次弯曲工艺,并对其进行了有限元数值模拟,分析了模具通道间隙、剪切角内侧倒角半径、模具弯曲半径对镁合金板材塑性变形的影响,初步优化了模具结构参数。【结果】根据有限元分析结果得出:1)模具通道间隙、剪切角内侧倒角半径越小,在剪切角处积累的应变越大,板材受到的剪切作用也越强,但过小的通道间隙、剪切角内侧倒角半径也会导致板材无法顺利进入ECAR-B模具,甚至出现开裂。2)模具弯曲半径大小也会制约板材的弯曲变形强弱,弯曲半径越小,则弯曲变形越强。【结论】根据分析结果初步优化后的模具通道间隙H=1.3 mm,剪切角内侧倒角半径r=2 mm,弯曲半径R=6 mm。该研究结果为ECAR-B工艺模具设计提供了理论依据,丰富了镁合金塑性变形理论。

[Objective]Magnesium alloys are greatly limited in their application due to their poor plasticity and strong basal texture at room temperature.Therefore,improving the room temperature plasticity of magnesium alloys and optimizing the basal texture of magnesium alloys are very important.[Method]On the basis of the multi-stage continuous shear bending process,the research group designed the equal diameter angle rolling single pass bending process and conducted finite element numerical simulation on it.The effects of mold channel gap,inner chamfer radius of shear angle,and mold bending radius on the plastic deformation of magnesium alloy plate were analyzed,and the mold structural parameters were preliminarily optimized.[Result]According to the finite element analysis results,it can be concluded that:1)The smaller the channel gap and the inner chamfer radius of the shear angle in the mold,the greater the accumulated strain at the shear angle,and the stronger the shear effect on the plate.However,too small channel gaps and the inner chamfer radius of the shear angle can also cause the plate to fail to enter the ECAR-B mold smoothly,and even crack.2)The size of the bending radius of the mold also affects the strength of the bending deformation of the sheet metal.The smaller the bending radius,the stronger the bending deformation.[Conclusion]Based on the analysis results,the preliminarily optimized mold channel gap H=1.3 mm,the inner chamfer radius of shear angle r=2 mm,and the bending radius R=6 mm.The research results provide a theoretical basis for the design of ECAR-B process molds and enrich the plastic deformation theory of magnesium alloys.