Experimental and numerical investigation on axial hydro-forging sequence of 6063 aluminum alloy tube

Abstract

To solve the drawbacks of thinning and poor thickness uniformity in tube hydroforming, a novel method known as axial hydro-forging sequence was developed. In this method, the deformation zones will be subjected to compression deformation throughout the hydro-forging stage to decrease the thinning and improve the thickness distribution compared with the traditional tube hydroforming. To verify the feasibility of this method, experiments and finite element simulations were designed and conducted. Subsequently, the effects of the internal pressure, friction, and reduction on thickness distribution were investigated. The results indicated that the thinning ratio can be decreased significantly by compression deformation. And the thickness of the deformation zone increases with increasing reduction. Furthermore, the thickness uniformity can be improved by a thickness “self-uniformity” in the hydro-forging stage, which was attributed to the von Mises stress distribution. It is demonstrated that the thickness distribution is related to the friction coefficient, but has little dependence on the internal pressure. Experimental and simulation results show that axial hydro-forging sequence is practicable to produce the variable-diameter tube.