Research Into Controlling the Material Flow for Electrohydraulic Forming Alloy Tubes by a Pulsed Magnet

Electrohydraulic forming is a kind of high-velocity forming process that can improve the formability of materials compared with quasi-static forming. Due to the lack of adequate material supplementation of the forming area, this method always faces problems such as uneven thinning and bursting when bulging tubes to required radial depths. To solve the above shortcomings and promote the material flow for the electrohydraulic forming process, this paper introduces an additional push coil to generate an axial electromagnetic force at the end of the tube. First, a finite element model was established to design the parameters of the push coil and the developed forming system. Then, a series of experiments using aluminum alloy tubes (AA6061-O) were conducted to verify the effectiveness of the proposed system. The results show that the limitation of the tube bulging depth can be increased by approximately 21.5%, and the thickness reduction can be reduced by more than 44% compared with conventional electrohydraulic forming. In addition, the forming morphology for tubes can be adjusted by the use of different combinations of discharge voltages for the push coil and exploding wire. The developed method and obtained results are of great value for improving the forming ability of electrohydraulic forming.