Abstract: A steel workpiece includes an alloy substrate comprising iron, about 1.4 to about 2.0 weight percent aluminum, and about 0 to about 1.0 weight percent silicon. The steel workpiece further includes a coating comprising zinc. A method of spot welding a workpiece stack-up that includes a pair of the steel workpieces includes providing the stack-up, contacting first and second electrodes to the steel workpieces, passing an electrical current through the stack-up, forming a weld nugget from molten mixing of the alloy substrates of the pair of steel workpieces, forming a boundary layer between the coating and the alloy substrate from dispersion of the coating into the alloy substrate and reaction of the zinc with the aluminum and the silicon to prevent molten mixing of the coating within the alloy substrate, and ceasing passage of the electrical current.

Abstract: A steel workpiece includes an alloy substrate comprising iron, about 1.4 to about 2.0 weight percent aluminum, and about 0 to about 1.0 weight percent silicon. The steel workpiece further includes a coating comprising zinc. A method of spot welding a workpiece stack-up that includes a pair of the steel workpieces includes providing the stack-up, contacting first and second electrodes to the steel workpieces, passing an electrical current through the stack-up, forming a weld nugget from molten mixing of the alloy substrates of the pair of steel workpieces, forming a boundary layer between the coating and the alloy substrate from dispersion of the coating into the alloy substrate and reaction of the zinc with the aluminum and the silicon to prevent molten mixing of the coating within the alloy substrate, and ceasing passage of the electrical current.

Abstract: A method of joining a multiple member work-piece includes providing a first steel work-piece having a first thickness and a second steel work-piece having a second thickness. The first thickness is at least twice the second thickness. A third material is disposed in contact with the second steel work-piece. For example, the third material may be in the form of a rivet, a plurality of pins, or a coating material. The method includes resistance welding the first and second work-pieces together. A bonded assembly includes the first and second steel members and the third material being bonded together, where the thickness of the first member is at least twice the thickness of the second member.

Abstract: A method of forming an assembly includes providing a metallic first workpiece having base and a first layer disposed on the base and adhering a second layer onto the first layer. One of the first and second layers is formed of a zinc-based material formed of at least a majority of zinc, and the other of the first and second layers is formed of a metallic alloying material having a melting point higher than the melting point of the zinc-based material. Preferably, the first layer is formed of the zinc-based material, and the second layer is formed of the metallic alloying material with the higher melting point. A metallic second workpiece is disposed in contact with the second layer. A welding operation is performed to join the first workpiece to the second workpiece. A welded assembly is also provided.

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 high temperature substrate coating to mitigate liquid metal embrittlement (LME) cracking in automobile vehicles includes a substrate. A coating is disposed on the substrate, the coating being one of a zinc-based material and an aluminum-based material, with the coating having a melting point of at least 500° C.

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 method of joining a multiple member work-piece includes providing a first steel work-piece having a first electrical resistivity and a second steel work-piece having a second electrical resistivity that is lower than the first electrical resistivity. A third material is disposed in contact with the second steel work-piece. The third material has an electrical resistivity that is greater than the second electrical resistivity. The method includes resistance welding the first and second work-pieces together. The third material may be in the form of a rivet, a third work-piece, or a coating material disposed between the first and second work-pieces. A bonded assembly includes steel members and a third material being bonded together, wherein the electrical resistivity of the second member is lower than the electrical resistivity of the first member, and the third material has an electrical resistivity that is greater than the electrical resistivity of the second member.

Abstract: A high temperature substrate coating to mitigate liquid metal embrittlement (LME) cracking in automobile vehicles includes a substrate. A coating is disposed on the substrate, the coating being one of a zinc-based material and an aluminum-based material, with the coating having a melting point of at least 500° C.

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 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 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: Aluminum-base alloy workpieces have surfaces with films of aluminum oxide which inhibit good contact with weld faces of resistance spot weld electrodes and the faying surfaces of, for example, sheet workpieces stacked for welding. Sometimes, the surfaces of the sheets also are coated with an adhesive or a sealer which further complicates welding. But in accordance with this invention, weld faces of opposing, round, copper welding electrodes are pressed against opposite outside surfaces of the sheets at a spot weld site and weld current is applied to the electrodes in accordance with a three-stage weld schedule to better form each weld. The weld schedule comprises a Conditioning stage (stage 1), a weld nugget Shaping stage (stage 2), and a weld nugget Sizing stage (stage 3).

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.

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 forming an assembly includes providing a metallic first workpiece having base and a first layer disposed on the base and adhering a second layer onto the first layer. One of the first and second layers is formed of a zinc-based material formed of at least a majority of zinc, and the other of the first and second layers is formed of a metallic alloying material having a melting point higher than the melting point of the zinc-based material. Preferably, the first layer is formed of the zinc-based material, and the second layer is formed of the metallic alloying material with the higher melting point. A metallic second workpiece is disposed in contact with the second layer. A welding operation is performed to join the first workpiece to the second workpiece. A welded assembly is also provided.

Abstract: A method of joining a multiple member work-piece includes providing a first steel work-piece having a first thickness and a second steel work-piece having a second thickness. The first thickness is at least twice the second thickness. A third material is disposed in contact with the second steel work-piece. For example, the third material may be in the form of a rivet, a plurality of pins, or a coating material. The method includes resistance welding the first and second work-pieces together. A bonded assembly includes the first and second steel members and the third material being bonded together, where the thickness of the first member is at least twice the thickness of the second member.

Abstract: A method of joining a multiple member work-piece includes providing a first steel work-piece having a first electrical resistivity and a second steel work-piece having a second electrical resistivity that is lower than the first electrical resistivity. A third material is disposed in contact with the second steel work-piece. The third material has an electrical resistivity that is greater than the second electrical resistivity. The method includes resistance welding the first and second work-pieces together. The third material may be in the form of a rivet, a third work-piece, or a coating material disposed between the first and second work-pieces. A bonded assembly includes steel members and a third material being bonded together, wherein the electrical resistivity of the second member is lower than the electrical resistivity of the first member, and the third material has an electrical resistivity that is greater than the electrical resistivity of the second member.

Abstract: A programmable polarity module that permits rapid on-demand control of the polarities assigned to the welding electrodes retained on a welding gun is disclosed. The programmable polarity module is electrically connectable to the welding gun and a direct current power supply unit to provide direct current to the welding electrodes for exchange during spot welding. A first interchangeable polarity output lug and a second interchangeable polarity output lug of the programmable polarity module permit the polarities of the welding electrodes to be switched without having to electrically disconnect the module from the welding gun.

Abstract: A method of resistance welding includes providing a first steel workpiece and second steel workpiece each having a zinc (Zn) coating. A first portion of the first steel workpiece and a second portion of the second steel workpiece are heated to at least about 500° C. allowing the zinc (Zn) coating to melt and dissolution of iron Fe from the first and second steel workpieces into the melted zinc (Zn) coating to form at least one of a plurality of Iron-Zinc intermetallic compounds. The first portion of the first workpiece and the second portion of the second workpiece are cooled to a first temperature. The first workpiece is disposed in contact with the second workpiece such that the first portion of the first workpiece is aligned with the second portion of the second workpiece. The first portion of the first workpiece is welded to the second portion of the second workpiece.