Abstract:A shear hydro-bending process was proposed to solve the difficulties in forming aluminum alloy rectangular tubes with small bending radius, which cannot be integrally manufactured using conventional bending methods. Numerical simulation and experimental research were conducted on defects during shear bending process. Effects of the internal pressure, feeding ratio and die inner bend corner radius were comprehensively investigated. The results show that four defects including wrinkling, cracking, pitting and folding appear if the internal pressure and the axial feeding and transversal stroke are not appropriate. The shear hydro-bent tube is performed successfully as the internal pressure ranges from 0.2σ_s to 0.9σ_s and the feeding ratio ranges from 1.0 to 1.1. It can be concluded that the shear hydro-bending is suitable to form aluminum alloy rectangular tubes with small bending radius by controlling the internal pressure, the axial feeding and the transverse stroke. There is a reasonable process window of the internal pressure and the feeding ratio, in which the tube can be successfully formed without defects.

Key words: aluminum alloys; hydroforming; shear hydro-bending; rectangular tube