A novel field shaper with slow-varying central hole for electromagnetic pulse welding of sheet metal

Electromagnetic pulse welding (EMPW) is a high-speed welding technology of solid state, which is of great significance to the welding of dissimilar metals. As a practical welding tool, the magnetic field shaper which is placed between the metal components and an electromagnetic coil has the function of concentrating the magnetic field, enhancing the electromagnetic force around the weld zone, and protecting the electromagnetic coil. However, there is a problem of insufficient welding area when using the traditional field shaper for welding. To overcome this issue, this paper carried out a numerical simulation of the principle of the field shaper for electromagnetic pulse welding of sheet metal by the method of joint simulation by ANSYS and COMSOL. The effects of diameter and configuration of the central hole of the field shaper on the peak value and distribution of the electromagnetic force upon the sheet metal were analyzed by simulation. Based on the results of the simulation, a novel field shaper with a slow-varying central hole was proposed, which can effectively improve the peak value and the uniformity of the distribution of the electromagnetic force. In the context, a new welding coefficient R is first proposed to evaluate the welding capability of the field shaper. On the basis of simulation, an electromagnetic welding platform was built for the welding of A1060 aluminum sheet to SS304 stainless steel plate both with a thickness of 1 mm. The experimental results show that the proposed field shaper can effectively improve the size of welding region.