19 Electromagnetic pulse welding of magnesium to aluminium sheets

Electromagnetic (EM) welding is based on application of Ampere’s law. Due to the ease of controlling magnetic fields, EM technique is more suitable for joining axis symmetric components. With special coil design, it can also be used to join Mg to Al sheets. Lorentz force is induced by eddy current and magnetic field, both of which are generated in the workpiece by a transient current in a coil in the vicinity. The jetting action due to the high velocity of impact removes the oxide layer present on the metal surface and creates a defect-free weld. EM welds of Mg to Al sheets obtained at optimum process parameters are found to be stronger than the parent metal. As EM setups are of high-voltage, the safety measures related to high-voltage are considered very important.