Seam-Joining between High-Strength Steel Sheet and Aluminum Alloy Sheet by Magnetic Pulse Welding

Abstract

In this paper, we describe the process parameters and the joining property of seam-welded sheets obtained by magnetic pulse welding. In this method, it is possible to weld an aluminum alloy sheet to a high-strength steel sheet (SPFH), for example, A5052-H34/SPFH or A6061-T6/SPFH. The aluminum sheet is deformed to a convex, because the electromagnetic force generated in the sheet is symmetrical with respect to the central axis. Therefore, the seam-welded sheet is joined by two lines, not a plane. Collision times of the three kinds of the aluminum sheets are examined for various gap lengths at 2.0 kJ discharge energy in experiments, and collision velocities are calculated using the collision times. The collision times of the three sheets are approximately the same at gap lengths less than or equal to 2.48 mm, because magnetic pulse welding is a phenomenon with a high strain rate. It is difficult to weld an aluminum sheet with a large flow stress to a high-strength steel sheet. Therefore the choice of process parameters is important, the influential parameters are discharge energy and gap length. We should choose the values of these two parameters such that the first collision occurs before the maximum discharge current.