A novel lubrication method for hydroforming of thin-walled aluminum alloy T-shaped tube

In this work, a novel lubrication approach for T-shaped tube hydroforming is developed to reduce the forming defects referred to the wrinkles that called intermediate semiring differential lubrication (ISDL), which reduced the dependence of the internal pressure and axial-feeding loading paths to make forming process easily. The T-shaped tube was divided into four zones: bulging zone, guiding zone, back zone, and middle back zone, and the ISDL method was to coat the bulging zone and whole or part of guiding zone with PTFE film and others with MoS 2 . Experimental results show that the ISDL method greatly reduced wrinkles in middle back zone of the T-shaped tube without wasting time to adjust the loading path again and again. Also, formulas related to the length and width for lubrication area of ISDL method was derived to guide the tube hydroforming process. The modified tribological performance by employing regional lubrication method improved the T-shaped tube hydroforming ability.