小弯曲半径薄壁不锈钢管推弯成形工艺研究

Research on Push Bending Process of Thin Wall Stainless Steel Tube with Small Bending Radius

相对弯曲半径越小,壁厚越薄,管材弯曲成形的成形难度越大。本文针对外径D = 86 mm,壁厚t = 0.8 mm,弯曲半径1 D的小弯曲半径不锈钢管开展了推弯成形工艺研究。基于有限元与实验相结合的方法,探究了管坯几何结构、反推力以及润滑方式对弯管成形质量的影响,结果表明:推弯成形管坯应采用补偿端头减少弯曲内侧材料堆积,避免起皱,对于90˚的目标弯管零件,45˚的补偿端头最为合适;反推力过小时,支撑力不足易起皱,反推力过大会导致摩擦增加阻碍弯曲内侧材料流动,增加起皱风险;通过分区域润滑,针对性调节材料流动,能够减少弯曲内侧增厚起皱风险。

The smaller the relative bending radius and the thinner the wall thickness, the more difficult the tube bending forming is. In this paper, the push bending process of small bending radius stainless steel tube with outer diameter D = 86 mm, wall thickness t = 0.8 mm and bending radius 1 D was studied. Based on the combination of finite element method and experiment, the influence of geometric structure of tube, reverse thrust and lubrication mode on forming quality of tube bending is investigated. The results show that: compensation end should be used to reduce the accumulation of bending material inside and avoid wrinkles. For 90˚ target bending parts, 45˚ compensation end is the most suitable. If the reverse thrust is too small, the support force is insufficient and wrinkling is easy. If the reverse thrust is too large, the friction will increase and the material flow inside the bending will be hindered, increasing the risk of wrinkling. The risk of thickening and wrinkling on the inside of the bend can be reduced by the targeted adjustment of the material flow through zonal lubrication.