Pulsed Magnet Design and Fabrication for Generating Background Magnetic Field in Discharge Current-Based Forming

Abstract

Discharge current-based forming (DCF) is a forming method that directly loads a pulse current into two parallel placed metal sheets connected in series, and the mutually exclusive electromagnetic force between them causes the sheets to be deformed. Compared with the electromagnetic forming (EMF), this method can improve the current density for the low-conductivity sheets. However, the forming height of the sheets is extremely poor due to the weak magnetic field generated by the pulsed current. In order to solve this problem, a new DCF approach adopted a pulsed magnet for wide sheets forming is proposed, which can provide a background magnetic field (BMF) with high uniformity and strength during the forming process. The influence of magnet parameters (shape, size, wire size, number of turns, etc.) on the magnetic field uniformity and strength at the forming region is analyzed by the finite element method, and the design scheme is listed. After that, the magnet is fabricated based upon the manufacturing technique of pulsed magnets, and the DCF and EMF experiments of AA1060 and SS304 sheets with 100 mm widths are carried out. The testing results show that the magnet can provide a 2.8 T BMF with more than 93% uniformity for the forming region. The forming results show that the forming height of sheets in DCF under BMF can be increased by 300% compared with that without BMF, and DCF has a huge advantage in comparison with EMF in forming low conductivity materials.