Magnetic Pulse Spot Welding: Application to Al/Fe Joining

Abstract

Magnetic pulse welding is a rapid process (takes place within few micro seconds) that joins both homogeneous and heterogeneous materials in the solid state. The process involves applying variable high current on an inductor to generate Lorentz forces on to the conductive primary part (flyer). To realize the weld it is necessary to accelerate the flyer to impact on to the secondary stationary part (base material) at a very high velocity attained over the distance, called air gap, between the parts. It is typically possible to perform welding of tubes and sheets provided there is an optimized air gap between the parts to be welded. As part of our work we have developed an innovative approach (Magnetic Pulse Spot Welding-MPSW) that eliminates the delicate task of maintaining the aforementioned air gap between the plates. The proposed method opens better viable perspectives for heterogeneous assembly of automotive structures or connecting batteries in a quasi-cold state. The developed approach has been validated on the heterogeneous assembly Al/Fe by tensile tests (quasi-static and dynamic) that attested the quality of welds.