Electromagnetic Pulse Forming of Carbon Steel Sheet Metal

Abstract

Electromagnetic pulse forming is a promising direct method for a high speed sheet metal forming of materials with high conductivity, like Al- and Cu-alloys. For metallic sheet with low conductivity, like carbon steel sheets, the frequency of the current through the forming coil must increase to create the same forming properties as for materials with high conductivity. Usually this frequency is not easy to change in an existing electromagnetic pulse system without exchanging of the capacitors. Anyway, this project have analysed the formability of two high strength steel sheet material, a carbon steel DP60 and a austenitic stainless steels, with and without a copper driver. The experiments were made on commercial electromagnetic pulse system from Poynting with a predefined current frequency through the forming coil. The geometries that were used for the electromagnetic pulse forming analysis were a cone, rectangular parts, and spherical dome. All physical parts were 3D digitised and the deviation were analysed against nominal reference objects. The spherical dome experiment was used to analyse the increase in formability of the high strength steel sheets compared with conventional stamping in an Erichsén sheet metal testing machine.