窄波距薄壁波纹管液力成形工艺研究

Research on hydro-mechanical forming process of thin-walled bellows with narrow wave space

为满足小直径窄波距薄壁金属波纹管产品的实际需求,开发出耦合模具运动的液力成形技术,从而提高波纹管的成形质量和生产效率。应用UG软件建立有限元模型,采用Dynaform有限元模拟软件对成形过程进行模拟,研究了管坯壁厚、模瓣间距、初波胀形压力和整形压力等关键工艺参数对波纹管成形质量的影响。结果表明:减薄率和波纹段直径随着管坯壁厚的增加而下降,随着膜瓣间距、初波胀形压力和整形压力的增加而升高。当管坯壁厚为0.5 mm、模瓣间距为6 mm、初波胀形压力为25 MPa、整形压力为100 MPa时成形效果最佳。开展了相关实验验证,验证结果表明模拟结果与实验结果相符,最大相对误差在5%以内,获得的波纹管成形质量优良,满足尺寸要求。

To meet the actual needs of thin-walled metal bellows with small diameter and narrow wave space,the hydro-mechanical forming process coupled with die movement was developed to improve the forming quality and production efficiency of bellows.The finite element model was established by UG software,and the forming process was simulated by Dynaform finite element simulation software.The effect of key forming parameters such as the wall thickness of tube blank,valve spacing,initial waveform bulging pressure and shaping pressure on the forming quality of bellows was studied.The results show that the thinning rate and the diameter of the corrugated section decrease with the increase of wall thickness of tube blank,and increase with the increase of valve spacing,initial bulging pressure and shaping pressure.When the wall thickness of tube blank is 0.5 mm,the valve spacing is 6 mm,the initial bulging pressure is 25 MPa,and the shaping pressure is 100 MPa,the forming effect is the best.Relevant experimental verification was carried out.The verification results show that the simulation results are consistent with the experimental results,and the maximum relative error is within 5%.The forming quality obtained bellows is good and meets the size requirements.