双路径自然增压铝合金2A12O充液拉深

Hydromechanical Deep Drawing of Aluminum Alloy 2A12O Assisted by Augmented Radial Pressure

基于铝合金等难成形板材的需要,提出了双路径自然增压充液拉深新技术。用有限元法对铝合金2A12O双路径自然增压充液拉深进行研究,探讨径向压力和液池压力单独变化时对壁厚分布的影响;得到合理的液池压力和径向压力加载路径以及合适匹配比;分析了该方法中液池压力和径向压力成比例变化时,壁厚分布的变化趋势。结果表明：采用15.0~20.0 MPa的液池压力,并将液池压力经增压活塞1.45倍增压后引到毛坯法兰边缘,可获得壁厚分布比较均匀、成形质量较高的零件,并能显著提高板料的极限拉深比;液池和径向压力的比例变化影响成形零件的壁厚分布,并且在不同的成形阶段其影响趋势不同。对模拟分析得到的压力加载路径和增压比进行实验,得到拉深比达2.65的铝合金2A12O杯形件,并建立其成形合理的压力区域。

Sheet hydroforming with its many advantages is gaining increasing popularity in industry.This study proposes a new method named hydromechanical deep drawing assisted by augmented radial pressure.By using aluminum alloy 2A12O,the effect of the pressures in both the die cavity and blank rim cavity on the wall thickness distribution is separately studied with the assistance of the finite element method（FEM）.The optimal pressures in the die cavity and the blank rim cavity as well as the proper ratio between them are obtained.Cups with more uniform thickness distribution and better quality can be successfully formed when the pressure in the die cavity is about 15.0-20.0 MPa together with a radial pressure in proportion of 1.45 to the cavity pressure.By using the loading paths obtained from simulation,a cup with a drawing ratio of 2.65 is successfully formed and the processing window for the cavity pressure is provided.