COVER PLATE WITH INTRUDING FEATURE TO IMPROVE AL-STEEL SPOT WELDING

摘要

A method of spot welding a workpiece stack-up that includes a steel workpiece and an adjacent aluminum alloy workpiece involves passing an electrical current through the workpieces and between opposed welding electrodes. The formation of a weld joint between the adjacent steel and aluminum alloy workpieces is aided by a cover plate that is located between the aluminum alloy workpiece that lies adjacent to the steel workpiece and the welding electrode disposed on the same side of the workpiece stack-up. The cover plate, which includes an intruding feature, affects the flow pattern and density of the electrical current that passes through the adjacent steel and aluminum alloy workpieces in a way that helps improve the strength of the weld joint.

主权项

1. A method of spot welding a workpiece stack-up that includes a steel workpiece and an adjacent aluminum alloy workpiece, the method comprising:
providing a workpiece stack-up that includes a steel workpiece and an aluminum alloy workpiece that overlaps and lies adjacent to the steel workpiece to establish a faying interface at a weld site, the workpiece stack-up having a first side and a second side, the first side of the workpiece stack-up being proximate the steel workpiece and the second side of the workpiece stack-up being proximate the aluminum alloy workpiece; locating a cover plate adjacent to the second side of the workpiece stack-up, the cover plate having an interior surface that confronts the second side of the workpiece stack-up and exterior surface that faces in an opposite direction from the interior surface, the cover plate further comprising an intruding feature aligned with the weld site; pressing a first weld face of a first welding electrode against the first side of the workpiece stack-up and pressing a second weld face of a second welding electrode against the exterior surface of the cover plate over the intruding feature, the first and second weld faces of the first and second welding electrodes being facially aligned at the weld site; and passing an electrical current between the first and second welding electrodes and through the workpiece stack-up at the weld site to create a molten aluminum alloy weld pool within the aluminum alloy workpiece, the molten aluminum alloy weld pool wetting an adjacent faying surface of the steel workpiece, and wherein the molten aluminum alloy weld pool solidifies into a weld joint that bonds the adjacent steel and aluminum alloy workpieces together at their faying interface upon ceasing passage of the electrical current through the workpiece stack-up.