铝合金矩形截面管充液成形工艺研究

摘要

目的：研究低延伸率和低厚向异性指数的铝合金管，在充液成形过程中的材料变形行为。方法采用低压预成形的方法来改善管坯材料的流动，并与传统不带内压的预成形结果进行了对比。结合有限元分析手段研究了铝管弯曲过程管坯尺寸、弯曲半径的选择对零件壁厚分布的重要性。结果有限分析方法结合试验研究表明，低压预成形可以有效抑制铝合金弯曲轴线管件的开裂。结论初始管材截面外壁周长应等于或略小于模具截面内壁周长；弯曲半径的选取要兼顾弯曲工艺难度和管坯贴模度；低压预成形能够大大改善矩形截面过渡圆角区的材料流动，避免破裂、死皱等典型缺陷的发生。%The aim of this study was to investigate the material deformation behavior of aluminum alloy with low elonga-tion and thickness anisotropy index during the tube hydroforming process. The method of low pressure pre-forming was con-ducted to improve the material flowing, and the results were compared with those by traditional pre-forming without pres-sure. The effect of tube dimensions and the bending radius on the wall thickness distribution during the bending process was analyzed by FEM. The FEM and experimental researches proved that the cracking of aluminum alloy curved tube can be restrained effectively through low pressure pre-forming. The initial outer diameter of the tube should be equal to or slightly less than the inside perimeter of the mold section. It is necessary to consider the difficulty of bending process and the tube's position in the mold while choosing the bending radius. The material flowing of rectangular section transition fil-let area can be greatly improved by the method of low pressure pre-forming, avoiding defects such as cracks and wrinkles.