INTRUDING FEATURE IN ALUMINUM ALLOY WORKPIECE 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 workpiece stack-up and between facially aligned welding electrodes in contact with opposed sides of the stack-up. The formation of a weld joint between the adjacent steel and aluminum alloy workpieces is aided by an intruding feature located in an aluminum alloy workpiece that provides and delineates one side of the workpiece stack-up and against which a welding electrode is pressed over the intruding feature at the weld site. The intruding feature affects the flow pattern and density of the electrical current that passes through the overlapping workpieces and is also believed to help minimize the effects of any refractory surface oxide layer(s) that may be present on the aluminum alloy workpiece that lies adjacent to the steel workpiece.

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 having a first side and an opposed second side, the workpiece stack-up comprising an aluminum alloy workpiece having an exterior surface that provides and delineates the second side of the workpiece stack-up, and further comprising a steel workpiece that overlaps, contacts, and establishes a faying interface with either a faying surface of the aluminum alloy workpiece that provides and delineates the second side of the workpiece stack-up or a faying surface of a second aluminum alloy workpiece within the workpiece stack-up, and wherein the aluminum alloy workpiece that provides and delineates the second side of the workpiece stack-up includes an intruding feature; 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 aluminum alloy workpiece that provides and delineates the second side of the workpiece stack-up, the first and second weld faces of the first and second welding electrodes being facially aligned at a weld site, and the second weld face of the second welding electrode being pressed against the exterior surface of the aluminum alloy workpiece that provides and delineates the second side of the workpiece stack-up over the intruding feature; 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 that wets an adjacent faying surface of the steel workpiece, and wherein the molten aluminum alloy weld pool solidifies into a weld joint that bonds the steel workpiece to either the aluminum alloy workpiece that provides and delineates the second side of the workpiece stack-up or the second aluminum alloy workpiece within the workpiece stack-up, whichever establishes the faying interface with the steel workpiece, upon ceasing passage of the electrical current through the workpiece stack-up.