Characteristics of Al/steel magnetic pulse tubular joint according to discharging time

The MPW (Magnetic pulse welding) process is governed by the electromagnetic force that results from electromagnetic interaction produced by a coil. To produce high electromagnetic force, the MPW process needs to charge high electrical energy through capacitors. The total capacitance and system inductance has an effect on the discharge time, and discharge time also has an effect on the joint. Therefore, the objective of this research is to analyze the effect of the discharge time on the joint and to quantify it using the FE-model. To achieve this, MPW has been performed using Al1070tube and S45Crod. After the experiment, the interfaces of the joint with variations of discharge time were observed utilizing a scanning electron microscope. In addition, a two dimensional electromagnetic-mechanical coupled FE-model has been developed for quantification. Experimental results demonstrated the impact of welded interfaces that have various lengths and amplitudes. It was confirmed from the numerical works that the creation of a wavy form is derived from the change of electromagnetic force according to the variation of discharge time. As the discharge time decreased, the lengths and amplitudes of the wave form decreased through the reduction of the generated electromagnetic force.