摘要
通过对规格为Φ70 mm×2 mm的不锈钢管进行内胀冷推弯成形数值模拟和实验研究,讨论了管坯结构、聚氨酯填块填充方式、反推力大小及润滑方式对弯曲角度为118.5°的大径厚比不锈钢弯管成形质量的影响。结果表明:管坯采用补偿端头结构可有效抑制弯曲内侧的材料堆积增厚,降低弯曲内侧的起皱风险;与冲头相接触的聚氨酯填块厚度为30 mm、其余聚氨酯填块厚度为15 mm时,填块的支撑效果更好且更有利于力的传递;反推力会影响内压及材料流动,反推力过小时,管坯内压不足,弯曲内侧不贴模且出现起皱现象,反推力过大时,摩擦力也相应增大,不利于内侧材料流动,会导致材料堆积引起管壁弯曲内侧起皱;弯管成形时摩擦力直接影响材料流动,采用分区域润滑的方式可改善管壁弯曲内侧的材料流动,有效减小管壁弯曲内侧的起皱风险,并有利于提高直端推出量。
Based on the numerical simulation and experimental study of internal expansion cold push bending for Φ70 mm×2 mm stainless steel tube, the influences of tube blank structure, filling method of polyurethane filling blocks, reverse thrust and lubrication method on the forming quality of stainless steel bent tube with large diameter to thickness ratio and the bending angle of 118.5° were discussed. The results show that the compensation end structure can effectively restrain the material accumulation and thickening, and reduce the risk of wrinkling in the bending inner side of tube blank. When the thickness of polyurethane filling block in contact with punch is 30 mm and the thickness of the rest of polyurethane filling blocks is 15 mm, the support effect of filling blocks is better and more conducive to force transmission. However, the reverse thrust affects the internal pressure and material flow. If the reverse thrust is too small, the internal pressure of tube blank is insufficient, and the bending inner side does not touch the die and is wrinkled. When the reverse thrust is too large, the friction force increases correspondingly, which is not conducive to the inner material flow to cause material accumulation and wrinkling in the bending inner side of tube wall. And the friction force directly affects the material flow during the tube bending. Thus, the method of regional lubrication can improve the material flow and effectively reduce the risk of wrinkling in the bending inner side of tube wall, and improve the extrusion of straight end.
作者
杨东
徐雪峰
范玉斌
伍世天
Yang Dong;Xu Xuefeng;Fan Yubin;Wu Shitian(School of Aviation Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China)
出处
《锻压技术》
CAS
CSCD
北大核心
2022年第10期154-162,共9页
Forging & Stamping Technology
基金
国家自然科学基金资助项目(51975267)。
关键词
推弯成形
弯管
反推力
管坯结构
润滑方式
push bending
bent tube
reverse thrust
tube blank structure
lubrication method
