Multistage axial hydro-forging sequence of double-stepped tube with large expansion ratio

Abstract

In order to manufacture the double-stepped tube with large expansion ratio, a multistage axial hydro-forging sequence was proposed by combination of hydroforming with movable dies in this paper. The new forming process is divided into four stages. In the second stage, hydro-forging stage, the thickness will be increased and the thinning ratio will be decreased due to the axial compression deformation, then the forming capacity of the tube will be improved. Experiments and finite element simulation were conducted to verify the feasibility of the proposed multistage axial hydro-forging sequence process. Experimental and simulation results showed that double-stepped tube with large expansion ratio can be produced with movable die design. At the same time, a better thickness distribution could be achieved. This investigation demonstrates that multistage axial hydro-forging sequence is a potential forming approach for manufacturing of large-expansion-ratio double-stepped tubes with high reliability. Keywords: Multistage axial hydro-forging sequence, Double-stepped tube, Large expansion ratio, Aluminum alloy