Abstract: A metallic component includes a core formed of steel. A zinc alloy layer is disposed on the core. The zinc alloy layer is formed of zinc and a very small amount of aluminum, such as 0.14 weight percent or less. A method of creating a component includes providing a steel core, providing a zinc bath consisting of essentially of 0.01 to 0.14 weight percent aluminum, and hot dipping the steel core into the zinc bath to form a zinc coating on the steel core resulting in a zinc-coated steel component. The aluminum may be provided in even lower contents, such as less than 0.08 weight percent, or even less than 0.05 weight percent. The zinc-coated steel component may then be spot welded to another component without first annealing the zinc-coated component. Rather, heat treating is performed locally at the weld joint by the welding procedure alone.

Abstract: A spot weld may be formed between an aluminum workpiece and an adjacent overlapping steel workpiece with the use of opposed spot welding electrodes that have mating weld faces designed for engagement with the outer surfaces of the workpiece stack-up assembly. The electrode that engages the stack-up assembly proximate the aluminum workpiece includes a central ascending convex surface and the electrode that engages the stack-up assembly proximate the steel workpiece has an annular surface. The mating weld faces of the first and second spot welding electrodes distribute the passing electrical current along a radially outwardly expanding flow path to provide a more uniform temperature distribution over the intended spot weld interface and may also produce a deformed bonding interface within the formed weld joint. Each of these events can beneficially affect the strength of the weld joint.

Abstract: A tip dresser cutter including a circumferential portion having a circular shape rotatable about an axis of rotation, a center portion located radially inward from the circumferential portion proximate the axis of rotation, and a cutting flute extending radially between the center portion and the circumferential portion. The cutting flute including a leading edge, a trailing edge, a radially inward canted surface extending between the leading edge and the trailing edge. The radially inward canted surface includes a first section extending between the center portion and a first location on the cutting flute and a second section extending between the first location on the cutting flute and a second location on the cutting flute. The second section of the radially inward canted surface including a curved portion that is parallel to a plane of rotation of the cutting flute.

Abstract: A series of many electrical resistance spot welds is to be formed in members of an assembled, but un-joined, body that presents workpiece stack-ups of various combinations of metal workpieces including all aluminum workpieces, all steel workpieces, and a combination of aluminum and steel workpieces. A pair of spot welding electrodes, each with a specified weld face that includes oxide-disrupting features, is used to form the required numbers of aluminum-to-aluminum spot welds, aluminum-to-steel spot welds, and steel-to-steel spot welds. A predetermined sequence of forming the various spot welds may be specified for extending the number of spot welds that can be made before the weld faces must be restored. And, during at least one of the aluminum-to-steel spot welds, a cover is inserted between the weld face of one of the welding electrodes and a side of a workpiece stack-up that includes the adjacent aluminum and steel workpieces.

Abstract: A method of resistance spot welding workpiece stack-ups of different combinations of metal workpieces with a single weld gun using the same set of welding electrodes is disclosed. In this method, a set of opposed welding electrodes that include an original shape and oxide-disrupting structural features are used to resistance spot weld at least two of the following types of workpiece stack-ups in a particular sequence: (1) a workpiece stack-up of two or more aluminum workpieces; (2) a workpiece stack-up that includes an aluminum workpiece and an adjacent steel workpiece; and (3) a workpiece stack-up of two or more steel workpieces. The spot welding sequence calls for completing all of the aluminum-to-aluminum spot welds and/or all of the steel-to-steel spot welds last.

Abstract: A method of resistance spot welding a workpiece stack-up that includes a steel workpiece and an aluminum workpiece includes adhering an aluminum patch to faying surface of a steel workpiece, positioning an aluminum workpiece over the aluminum patch and the steel workpiece to assemble a workpiece stack-up, passing an electric current through the workpiece stack-up to create a molten aluminum weld pool, and terminating passage of the electric current to solidify the molten aluminum weld pool into a weld joint that bonds the steel and aluminum workpieces together through the aluminum patch. A workpiece stack-up having a weld joint that bonds an aluminum workpiece and a steel workpiece together through an aluminum patch is also disclosed. The weld joint establishes a bonding interface with the faying surface of the steel workpiece, and the aluminum patch is adhered to the faying surface of the steel workpiece around the weld joint.

Abstract: A cutting tool that can simultaneously cut and restore asymmetric weld face geometries of two welding electrodes that are subject to different degradation mechanisms is disclosed along with a method of using such a cutting tool during resistance spot welding of workpiece stack-ups that include dissimilar metal workpieces. The cutting tool includes a first cutting socket and a second cutting socket. The first cutting socket is defined by one or more first shearing surfaces and the second cutting is defined by one or more second shearing surfaces. The first shearing surface(s) and the second shearing surface(s) are profiled to cut and restore a first weld face geometry and a second weld face geometry, respectively, that are different from each other upon receipt of electrode weld faces within the cutting sockets and rotation of the cutting tool.

Abstract: A method of manufacturing a resistance weld in at least three overlying sheet metal layers includes the steps of: (1) providing a first sheet metal layer having a first thickness; (2) providing a second sheet metal layer having a second thickness; (3) providing a filler material on the second sheet metal layer; (4) providing a third sheet metal layer having a third thickness onto the filler material and the second sheet metal layer wherein the third thickness is less than each of the first and the second thicknesses; (5) pressing a pair of welding electrodes against a pair of opposing outer surfaces with the filler material disposed therebetween; and (6) passing an electric current between the pair of electrodes through the filler material and the first, second, and third sheet metal layers to form a weld nugget which penetrates into at least the first and second sheet metal layers.

Abstract: A method to mitigate liquid metal embrittlement cracking in resistance welding of galvanized steels includes modifying at least one face of a steel member to create a first workpiece by: applying a zinc containing material in a first layer to the at least one face of the steel member; and spraying a second layer of a copper containing material onto the first layer of the zinc containing material. The at least one face of the first workpiece is abutted to a second workpiece of a steel material. A resistance welding operation is performed to join the first workpiece to the second workpiece. A temperature of the resistance welding operation locally melts the zinc containing material and the copper containing material to create a brass alloy of the zinc containing material and the copper containing material.

Abstract: A cutting tool that can simultaneously cut and restore asymmetric weld face geometries of two welding electrodes that are subject to different degradation mechanisms is disclosed along with a method of using such a cutting tool during resistance spot welding of workpiece stack-ups that include dissimilar metal workpieces. The cutting tool includes a first cutting socket and a second cutting socket. The first cutting socket is defined by one or more first shearing surfaces and the second cutting is defined by one or more second shearing surfaces. The first shearing surface(s) and the second shearing surface(s) are profiled to cut and restore a first weld face geometry and a second weld face geometry, respectively, that are different from each other upon receipt of electrode weld faces within the cutting sockets and rotation of the cutting tool.

Abstract: A method of resistance spot welding a workpiece stack-up that includes a first steel workpiece and a second steel workpiece. The method includes several steps. The first steel workpiece can have a first surface coating. One step involves applying a filler metal to a surface of the first steel workpiece. Another step involves bringing a surface of the second steel workpiece to adjoin the filler metal. Yet another step involves clamping a first welding electrode and a second welding electrode on the first and second steel workpieces. And another step involves passing electrical current between the first and second welding electrodes and hence through the filler metal. And yet another step involves terminating passage of the electrical current in order to establish a weld joint between the first and second steel workpieces.

Abstract: A method of resistance spot brazing a workpiece stack-up that includes a first thin-gauge steel workpiece and a second thin-gauge steel workpiece. The method includes several steps. A first step involves applying a filler material to a surface of the first thin-gauge steel workpiece. A second step involves bringing a surface of the second thin-gauge steel workpiece to adjoin the filler material. A third step involves clamping a first welding electrode and a second welding electrode on the first and second thin-gauge steel workpieces and over the filler material. A fourth step involves passing electrical current between the first and second welding electrodes and hence through the filler material. And a fifth step involves terminating passage of the electrical current in order to establish a brazed joint between the first and second thin-gauge steel workpieces.

Abstract: A welding electrode for use in resistance spot welding an assembly of overlying metal workpieces that includes an aluminum alloy workpiece is disclosed. The welding electrode includes a body, a convex weld face at one end of the body, and ringed protrusions that project outwardly from the convex weld face. The ringed protrusions are positioned to make contact with, and indent into, a surface of the aluminum alloy workpiece when the convex weld face is pressed against the aluminum alloy workpiece during a spot welding event. When brought into contact with the surface of the aluminum alloy workpiece, the ringed protrusions disrupt the oxide film present on the aluminum alloy workpiece surface, which improves the spot welding process.

Abstract: A welding electrode for use in engaging an aluminum alloy workpiece during a spot welding process has a weld face that includes a base surface and a plurality of circular ridges that project outwardly from the base surface. The circular ridges are blunted, and their presence on the weld face provides the first welding electrode with several useful capabilities, including the ability to establish better mechanical and electrical contact with the aluminum alloy workpiece.

Abstract: A method of resistance spot welding steel workpieces—at least one of which includes a high-strength steel substrate having a tensile strength of 1000 MPa or greater—involves passing a pulsating DC electrical current between a pair of aligned welding electrodes that are pressed against opposite sides of a workpiece stack-up that includes the steel workpieces. The pulsating DC electrical current delivers sufficient power through the weld site by way of electrical current pulses to initiate and grow a molten steel weld pool at each faying interface within the workpiece stack-up that solidifies into a weld nugget of uniform hardness. In other words, each of the weld nuggets formed by the pulsating DC electrical current does not include soft, coarse, and alloy deficient shell regions that tend to reduce the strength of the weld nugget.

Abstract: A resistive welding electrode includes at least a weld face constructed of a refractory-based material that exhibits an electrical conductivity that is less than or equal to 65% of the electrical conductivity of commercially pure annealed copper as defined by the International Annealed Copper Standard (IACS). A method of using the resistive welding electrode to resistance spot weld a workpiece stack-up that includes an aluminum alloy workpiece and steel workpiece that overlap and contact each other at a faying interface is also disclosed.

Abstract: A workpiece stack-up that includes at least a steel workpiece and an adjacent and overlapping aluminum workpiece can be resistance spot welded by a multi-stage spot welding method. The multi-stage spot welding method involves initially forming a weld joint between the steel and aluminum workpieces. The weld joint extends into the aluminum workpiece from the faying interface of the two workpieces and includes an interfacial weld bond area adjacent to and joined with the faying surface of the steel workpiece. After the weld joint is initially formed, the multi-stage spot welding method calls for remelting and resolidifying at least a portion of the weld joint that includes some or all of the interfacial weld bond area. At least a portion of the resultant refined weld joint may then be subjected to the same remelting and resolidifying practice, if desired. Multiple additional practices of remelting and resolidifying may be carried out.

Abstract: A welding electrode includes a weld face that has a convex base weld face surface and a plurality of ringed ridges that are radially spaced apart on the base weld face surface and surround a central weld face axis. The plurality of ringed ridges including an innermost ringed ridge and an outermost ringed ridge. The innermost ringed ridge is located closest to the central weld face axis and rises above a central portion of the base weld face surface, and the outermost ringed ridge is located farthest from the central weld face axis and rises above an outer peripheral portion of the base weld face surface. At least one of the plurality of ringed ridges is a discontinuous ringed ridge.

Abstract: A method of spot welding a workpiece stack-up that includes a steel workpiece and an aluminum alloy workpiece involves passing an electrical current through the workpieces and between welding electrodes that are constructed to affect the current density of the electrical current. The welding electrodes, more specifically, are constructed to render the density of the electrical current greater in the steel workpiece than in the aluminum alloy workpiece. This difference in current densities can be accomplished by passing, at least initially, the electrical current between a weld face of the welding electrode in contact with the steel workpiece and a perimeter region of a weld face of the welding electrode in contact with the aluminum alloy workpiece.

Abstract: A workpiece stack-up that includes at least a steel workpiece and an aluminum-based workpiece can be resistance spot welded by employing a multi-stage spot welding method in which the passage of electrical current is controlled to perform multiple stages of weld joint development.