Abstract: Compared with circular tubular parts, hydroforming rectangular section pipe has the advantages of simple process and high forming quality. It has great development potential and application prospect in lightweight forming technology in automobile industry. In order to study the forming ways of hydroforming rectangular section parts, circular pipe fittings are taken as the research object in this paper. The mechanical parameters of the forming material are obtained through experiments, and the stress-strain curve is obtained by universal tensile machine, which is transformed into the real stress-strain curve. An experimental platform was built to study the hydroforming experiment of circular pipe without axial feed, and the key parameters of circular pipe forming and the fillet fitting were obtained. The nonlinear finite element software DYNAFORM is used to calculate the forming process of circular pipe fittings. Through experimental comparison, the results show that the deviation between the experimental and numerical results is less than 5%, and the coincidence rate is high, which verifies the correctness of the finite element model and calculation method in this paper, and provides a necessary reference for engineering application. Keywords: Rectangular section; Hydroforming; Numeral calculations

Key words: Rectangular section; Hydroforming; Numeral calculations

摘要： 液压成形的矩形截面管件由于工序较为简单、成形质量高，相比于圆形管状零件而言，具 有更大的抗弯模量等优点，在汽车行业轻量化成形技术中有较大发展潜力和应用前景。为了研究 液压成形矩形截面零件成形规律，文章以圆形管件为研究对象。通过实验获取成形材料的力学参 数，采用万能拉伸机获取应力应变曲线，将其转化为真实应力应变曲线。搭建实验平台，对圆管 无轴向进给液压成形实验进行研究，获取圆形管件成形的关键参数及其圆角贴合情况。采用非线 性有限元软件 Dynaform 对圆管件成形过程进行数值计算，通过实验对比，结果表明实验与数值计 算结果偏差在 5%以内，吻合率较高，从而验证了文章有限元模型建立与计算方法的正确性，为工 程应用提供必要的参考。

关键词: 矩形截面；液压成形；数值计算