Evaluation model of electromagnetic pulse welding effect based on Vc-β trajectory curve

As a non-heat input solid-state joining technology, electromagnetic pulse welding (EMPW) has many advantages in the connection of dissimilar metals. Finite element (FE) methods are often used to design the EMPW equipment, explore the parameters and analyze the transient process. However, it is difficult to reflect the welding effect directly. This work proposed a welding effect evaluation model based on the welding window theory and the Vc-β trajectory curve obtained in the FE simulation. A FE model coupling the circuit-magnetic-structure field was established in COMSOL software to simulate the EMPW process of the Cu plate and Al plate. The Vc-β trajectory curve and welding traces were obtained according to the simulation results. An experimental platform WD-28 was used to carry out the welding experiments of Cu–Al plates at different discharging voltages. The welding traces were measured through SEM method and compared with the simulation results. According to the comparative result, the empirical constant of the calculation formula for the lower boundary of the welding window was adjusted into 1.6, so that the evaluation result was consistent with the experimental result. This work can provide a new method for evaluating directly the welding effect through the FE simulation results.