A novel differential lubrication method is proposed to improve the deformation behavior of L-shaped thin-walled with relative bending radius of 1 in push-bending process. The optimized tube blank is divided into four zones: inner deformation zone, inner guide zone, outer deformation zone and outer guide zone, which are lubricated with different lubricants. The differential lubrication and uniform lubrication methods for tube push-bending are first explored by means of simulation and experiments. The simulation results show that the differential lubrication method is more effective than the uniform lubrication method in suppressing wrinkles and expanding the process window. The outer thickness of tube increases with the increase of friction coefficient of the outer guide zone and the outer deformation zone, while the extension of tube end decreases with the increase of friction coefficient in any zone. Furthermore, with the proposed differential lubrication method, L-shpaed push-bending experiments of 5A02 aluminum alloy and 1Cr18Ni9 tube with relative bending radius of 1 were carried out to investigate this effect. The experimental results showed that the differential lubrication method effectively avoided wrinkling and the experimental results agreed well with the simulation results in wall thickness distribution and the extension of tube end.

提出了一种新型的差动润滑方法，以改善相对弯曲半径为1的L形薄壁在推弯过程中的变形行为。优化后的管坯分为四个区域：内部变形区域，内部导向区域，外部变形区域和外部导向区域，分别用不同的润滑剂润滑。首先通过仿真和实验探索了管推弯的差分润滑和均匀润滑方法。仿真结果表明，差异润滑法比均匀润滑法在抑制皱纹和扩大加工范围方面更为有效。管的外部厚度随着外部引导区和外部变形区的摩擦系数的增加而增加，在任何区域，管端的延伸都随着摩擦系数的增加而减小。此外，采用提出的差动润滑方法，对5A02铝合金和1Cr18Ni9相对弯曲半径为1的管进行L形推弯试验，以研究这种效果。实验结果表明，差动润滑法有效地避免了起皱现象，并且与壁厚分布和管端延伸的模拟结果吻合良好。