超薄壁不锈钢波纹管件液压成形工艺研究

Research on hydroforming process of stainless steel bellows withultra-thin wall

为了解决传统拼焊制造超薄壁不锈钢波纹管弹性差、寿命短、易破裂等问题,采用液压成形技术成形超薄壁不锈钢波纹管件。针对超薄壁不锈钢波纹管件截面形状复杂以及管壁易失稳起皱破裂的成形难点,设计了不同的加载路径。利用CATIA进行建模,使用Dynaform有限元分析软件进行数值模拟。基于波纹管成形过程中的波高与壁厚减薄情况研究了模具间隙、预胀形内压和整形压力对成形质量的影响规律。试验结果表明,对于复杂异形截面的填充,管内压强和轴向进给的增大有利于材料流动进入圆角区域以及管坯与模具的贴合。对于内径Φ50 mm,壁厚0.4 mm的复杂截面波纹管,预胀形内压7.5 MPa,整形压力20 MPa,轴向进给为20 mm为最佳参数匹配。开展了相关试验,验证了模拟结果与试验结果相符,获得的波纹管满足尺寸与性能的需求。

To solve the problems of poor elasticity,short service life and easy rupture of stainless steel bellows with ultra-thin wall made by traditional welding,the hydroforming technology was used to form the stainless steel bellows with ultra-thin wall.Aiming at the forming difficulties that the section shape is complicated and the tube wall is easy to wrinkle and crack of stainless steel bellows with ultra-thin wall,the different loading paths were designed.CATIA was used for modeling and Dynaform finite element analysis software was used for numerical simulation.Based on the wave height and wall thickness thinning during forming process of bellows,the influence laws of die clearance,pre-bulging internal pressure and shaping pressure on the forming quality were studied.The experimental results show that for the filling of complex special-shaped section,the increase of pressure in tube and axial feed is conducive to the material flow into the rounded corner area and the fitting of the tube billet and die.For the special-shaped section bellows with inner diameter ofΦ50 mm and wall thickness of 0.4 mm,pre-bulging internal pressure of 7.5 MPa,shaping pressure of 20 MPa and axial feed of 20 mm are the best parameter matching.The related experiments were carried out,it is verified that the simulation results agree with the experimental results,and the obtained bellows meet the requirements of size and performance.