INSIDE BEAD FORMING OF ALUMINUM TUBE BY ELECTROMAGNETIC FORMING

In this paper, the inside bead forming of aluminum tube (A6063TD) by e lectro-magnetic forming (EMF) is reported experimentally and numerical ly. The shape of the bead was affected by the change of the discharge voltage and the dimensions of a groove at a beading die which have a w idth and a shoulder radius. With the increase of the discharge voltage and the shoulder radius, the bead height increased due to the increas ing of the bending moment. On the discharge voltage of over 4 kV (400 mu F), the bead height rapidly increased so that the aluminum tube ent ered the groove at the beading die from both sides. Therefore the thic kness strain at the top of the bead increased, the longitudinal strain of the aluminum tube saturated, and a necking appeared at the bead ne ar the shoulder part of the beading die. Also, the simulation of the b ead forming was carried out by using MARC and compared with the experi mental results. (C) 1998 Elsevier Science S.A. All rights reserved.