Research on the influence factors of thin-walled 5A02 aluminum alloy Y-shaped tube in the hydroforming based on differential lubrication.

Abstract

Abstract In this paper, the effects of the lubrication method, the end face angle of the middle punch and its back pressure on the wrinkling and cracking during the hydroforming of the Y-shaped tube were discussed.It is of great significance to the hydroforming of thin-walled 5A02 aluminum alloy Y-shaped tube with large transition fillet that are asymmetric in both longitudinal and transverse directions. MoS2 and PTFE film were used to lubricate different areas of the Y-shaped tube. Designed end face Angle of 0° and 13.5° for middle punch. Constructed a stepped pressure-feed loading path.The test results show that the combination of MoS2-PTFE film only lubricated the bulging zone and partial back zone of the Y-shaped tube and didn’t lubricate other zones, which could effectively increase the flow rate of material in the expansion zone and prevent the main tube from wrinkling. Using the 13.5°middle punch with a back pressure of 7MPa and a stepped-increasing pressure-feed loading path could not only effectively suppress the cracking of the branch tube in the early stage of forming, but also obtain the ideal branch tube height and surface.