大型薄壁U形波纹管轴向低压压形的形状精度  

Shape accuracy for large thin-wall U-shaped bellows under axial low pressure hydroforming

作　　者：杨程 李斯棠 孙磊 林才渊 胡德友 初冠南[2] Yang Cheng;Li Sitang;Sun Lei;Lin Caiyuan;Hu Deyou;Chu Guannan(College of Mechanical&Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;School of Materials Science and Engineering,Harbin Institute of Technology-Weihai,Weihai 264209,China;Harbin Institute of Technology-Weihai Innovation Park Co.,Ltd.,Weihai 264209,China;Tianjin Long March Launch Vehicle Manufacturing Co.,Ltd.,Tianjin 300462,China)

机构地区：[1]南京航空航天大学机电学院,江苏南京210016 [2]哈尔滨工业大学(威海)材料科学与工程学院,山东威海264209 [3]哈工大(威海)创新创业园有限责任公司,山东威海264209 [4]天津航天长征火箭制造有限公司,天津300462

出　　处：《锻压技术》2022年第10期145-153,共9页Forging & Stamping Technology

基　　金：国家基金委航天联合基金重点项目(U1937205);国家自然科学基金面上项目(51475121);山东省重大科技创新工程(2020CXGC010303)。

摘　　要：为了克服大直径U形波纹管液压成形时成形内压过高、设备吨位要求大等缺点,提出了一种轴向低压压形工艺成形该类零件。通过实验与数值模拟分析相结合的方式,分析了初始内压、最终内压和轴向进给3种工艺参数对形状精度(圆角填充、回弹)的影响。对于圆角填充,初始内压和轴向进给的增大,会导致管坯在波峰圆角区贴模更紧密,在波谷圆角区脱模程度加重,而当最终内压较小时,波峰的填充不完全。对于回弹,初始内压和轴向进给的增大以及最终内压的减小均有利于抑制回弹。最终得出了最佳工艺参数组合,即初始内压为1.2 MPa、最终内压为4.0 MPa、轴向进给为31.5 mm。同时,对波纹管的应力状态进行分析,得出了回弹产生的原因,并通过模具修正对回弹进行补偿。最终,实验成形了尺寸精度在0.5 mm以内、内径为Φ340 mm、壁厚为1.5 mm的U形波纹管,验证了工艺的可行性。In order to overcome the disadvantages of high internal pressure and large equipment tonnage during the hydroforming of U-shaped bellows with large diameter,an axial low pressure hydroforming process was proposed to produce this part,and the influences of initial internal pressure,final internal pressure and axial feeding on the shape accuracy(corner filling and springback)were analyzed by combining finite element simulation analysis and experiment.Then,for the corner filling,the increase of initial internal pressure and axial feeding caused the tube to adhere to the die more closely in the corner area of wave crest,and the degree of demoulding in the corner area of wave valley was increased.When the final internal pressure was small,the filling of wave crest was incomplete.For the springback,the increase of initial internal pressure and axial feeding and the decrease of final internal pressure were beneficial to restrain springback.And the best process parameters were the initial internal pressure of 1.2 MPa,the final internal pressure of 4.0 MPa and the axial feeding of 31.5 mm.At the same time,the stress state of bellows was analyzed,and the reason of springback was obtained,then the springback was compensated by die modification.Finally,the U-shaped bellows with the inner diameter ofΦ340 mm,the wall thickness of 1.5 mm and the dimension accuracy of less than 0.5 mm were formed experimentally,which verifies the feasibility of the process.

关 键 词：波纹管 轴向低压压形 形状精度 初始内压 最终内压 轴向进给 

分 类 号：TG394[金属学及工艺—金属压力加工]