Abstract: Texture for breaking oxide layers on an electrode and a tool applying texture to an electrode is disclosed. The tool may be used during a pattern creating process where the texture is applied to the electrode tip, or may be used during a re-conditioning process where a new texture is applied to a deteriorated electrode tip. The textured surface may include a pattern of raised or depressed features (teeth, knurls, protrusions, depressions, ridges, asperities, cross-hatches, parallel or non-parallel lines, star shapes, triangles, hexagons, etc.). The tool includes a plate having an upper side and a lower side, and a texture surface is arranged on one or both of the upper and lower sides of the tool. The tool's texture surface may include various asperities or patterns, which are imprinted onto the electrode tips by squeezing the electrodes against the upper and lower sides of the tool.

Abstract: A spoon instrument and a method of manufacturing the same is provided. Two spoons are joined together near their handle's distal end by temporarily aligning and fixing this aligned arrangement by way of an alignment fixture. The alignment fixture provides spaced apart, parallelly arranged plates that define an ideal joint location between the two spoons formed by spot welding, as opposed to welding using consumable or filler material.

Abstract: An apparatus includes a housing, a pin, a mechanism and a sensor. The housing is configured to receive a weld head. The pin is configured to move linearly relative to said housing. The mechanism is configured to convert a position of said pin into a displacement. The sensor is configured to generate a value representative of said position of said pin based on said displacement.

Abstract: Thermal spray gun (1) and/or nozzle (120) includes a nozzle body and a liner material (123) arranged within the nozzle body. A material of the nozzle body has a lower melting temperature than that of the liner material (123). A wall thickness (C) of the liner material (123) has a value determined in relation to or that corresponds to a wall thickness (D) of the nozzle body. Alternatively or additionally, a ratio of a total wall thickness of a portion of a nozzle (120) to that of a wall thickness (C) of the liner material (123) has a value determined in relation to or that corresponds to the wall thickness (C) of liner material (123).

Abstract: A method of resistance spot welding that enables an improvement of a weld strength of steel plates having different plate thicknesses while inhibiting generation of spatters is provided. One aspect of the present disclosure is the method of resistance spot welding, the method including welding a workpiece made of layered steel plates with a resistance spot welding apparatus. The resistance spot welding apparatus includes a first electrode configured to contact a first steel plate among the steel plates, and a second electrode configured to contact, among the steel plates, a second steel plate that is thinner than the first steel plate, and the second electrode being arranged such that the workpiece is interposed between the first electrode and the second electrode. The welding includes welding while moving the second electrode relative to the first electrode in a direction parallel with a plate surface of the second steel plate.

Abstract: A guide hole is constituted of a large-diameter hole, a medium-diameter hole, and a small-diameter hole. A sliding part fitted in the guide hole is formed of a synthetic resin material. A large-diameter portion of the sliding part is fitted in the large-diameter hole in a slidable state, and a medium-diameter portion is fitted in the medium-diameter hole in a slidable state. A movable end surface of the sliding part is in close contact with a stationary inner end surface of the guide hole. By configuring a width dimension of the movable end surface to be less than half of a thickness dimension of the large-diameter portion, a pressurizing force of the movable end surface is increased and a minute metal piece is pushed from the movable end surface into a base material of the sliding part, and a thickness dimension of the medium-diameter portion is set large.

Abstract: An electrode tip portion is provided with a projection portion and a plurality of recess portions. The plurality of the recess portions are independent of one another, and are provided at the electrode tip portion in a dispersed manner. The projection portion is a region other than regions where the recess portions are provided, and is configured to be equipped with a continuous surface that continues in regions among the plurality of the recess portions.

Abstract: Disclosed is a device for protecting the back wall of a fuel injector nozzle during drilling of nozzle holes.

Abstract: A wire for gas-shielded arc welding includes, based on a total mass of the wire: C: 0.01 mass % or more and 0.10 mass % or less, Si: 0.05 mass % or more and 0.55 mass % or less, Mn: 1.60 mass % or more and 2.40 mass % or less, Ti: 0.05 mass % or more and 0.25 mass % or less, Cu: 0.01 mass % or more and 0.30 mass % or less, S: 0.001 mass % or more and 0.020 mass % or less, N: 0.0045 mass % or more and 0.0150 mass % or less, Al: 0.10 mass % or less, and P: 0.025 mass % or less, with the remainder being Fe and inevitable impurities. In the wire, the following relationship is satisfied: 0.1?[Ti]/[Si]?3.0, where [Si] is the content of Si (mass %) and [Ti] is the content of Ti (mass %).

Abstract: A center pipe is used in a plasma torch including a base portion and an electrode to supply cooling water into the electrode. The center pipe includes a pipe body and a contact piece. The pipe body has a tube-like shape with a cooling water channel therein. The pipe body is electrically conductive and configured to be electrically connected to an external power source via the base portion. The contact piece is arranged radially outside the pipe body at an intermediate position between a base end surface and a tip end surface of the pipe body. The contact piece is electrically conductive and energizes the electrode through contact with an internal circumferential surface of the electrode. The base end surface is disposed outside the electrode when the center pipe is inserted into the electrode. The pipe body is configured to be electrically connected to the electrode via the contact piece.

Abstract: Arc saw blades and systems and methods for segmenting components utilizing improved arc saw blades.

Abstract: A plasma nozzle (120) having a nozzle body and a liner material (123) arranged within the nozzle body. The liner material (123) has a higher melting temperature than the nozzle body and includes one of a Tungsten alloy having a cross-sectional thickness (C) significantly greater than 0.25 mm, Molybdenum, Silver and Iridium.

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 welding electrode is disclosed that includes an electrode welding shell and a blind adapter that are joined together to cooperatively define an internal cavity. The electrode welding shell and the blind adapter may be integrally formed or they may be distinct components that are attached together. The presence of the internal cavity defined by the electrode welding shell and the blind adapter reduces the thermal mass of the welding electrode and slows the rate of conductive heat transfer from the weld face to a cooling fluid, which allows in the center of the weld face to retain heat for a longer duration once current flow through the welding electrode is terminated, thereby positively affecting the spot welding process for particular types of workpiece stack-ups including those that include an aluminum workpiece and an overlapping adjacent steel workpiece.

Abstract: An electrode cap and adapter assembly includes a cap having a useful life line inscribed thereon. The cap may be either a circumferentially configured internally finned cap or a self-dressing internally finned cap. The male/female adapter is used to mount a female cap to a male shank.

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 spot welding electrode of a donut-shaped electrode wherein even when a welded member of a steel sheet is slanted with respect a plane perpendicular to an axis of the spot welding electrode, a cross tensile strength (CTS) of the spot welded joint can be improved. The donut shape spot welding electrode according to the present invention has an electrode tip and an electrode support. The electrode tip contacts the electrode support to be able to move. Due to this, it is possible to strikingly raise the ability of the donut-shaped electrode to track a steel sheet and make the entire surface of the donut shape contact-and-conduction part contact the steel sheet, so it is possible to secure a high CTS value even if the steel sheet is slanted.

Abstract: A sliding member integrated with a guide pin is inserted into a guide hole of an electrode main body. An elastic ring is integrated with the guide pin under a state in which the guide pin passes through the elastic ring. A portion of the sliding member has a pressurizing end surface configured to press the elastic ring against an inner end surface of the guide hole. When the pressurizing end surface presses the elastic ring against the inner end surface, flow of the cooling air is interrupted. When the elastic ring is away from the inner end surface, the cooling air is allowed to flow.

Abstract: A welding electrode unit includes a repositioning device that is movable. The repositioning device includes an energy storage device by way of which a welding electrode is connected directly or indirectly with the energy storage device can have a force applied to it for the purpose of a repositioning movement. The repositioning device is movable into a welding position by way of a forward movement and can be locked in the welding position.

Abstract: A torch head for a liquid-cooled plasma arc torch is provided. The torch head includes a torch body and a torch insulator, coupled to the torch body, having a substantially non-conductive insulator body. The torch insulator includes (i) a first liquid coolant channel, disposed within the insulator body, configured to conduct a fluid flow from the torch head into a consumable cartridge along a first preexisting flow path, (ii) a first liquid return channel, disposed within the insulator body, configured to return at least a portion of the fluid flow from the cartridge to the torch head along the first preexisting flow path, and (iii) a gas channel, disposed within the insulator body, configured to conduct a first gas flow from the torch head to the cartridge along a second preexisting flow path. The first and second preexisting flow paths are fluidly isolated from each other.

Abstract: A plasma torch having an open end from which a plasma plume is emitted in use is disclosed. The plasma torch includes a central cathode rod, a grounded conductive tube having an open end and being arranged around the cathode and spaced therefrom to form a first cylindrical cavity open at one end; and a high voltage electrode having a dielectric barrier material at a radially inward-facing surface thereof and being arranged around the grounded conductive tube and spaced apart therefrom to form a second annular cylindrical cavity open at one end. A constant direct current (DC) electrical power plus a high voltage pulsed electrical power is provided to the cathode producing an arc discharge in the first cavity between the cathode and grounded tube to generate a central thermal plasma emitted at an open end of the first cylindrical cavity.

Abstract: A device for processing—particularly stripping insulation, cutting, contacting, fitting-out, connecting, measuring or checking—a cable that has at least one insulated electrical conductor includes a metal tool movable relative to the cable and a measuring device by which contact with the electrical conductor by the tool is detectable. The tool is connected with a first electrode body movable relative to a second electrode body so that through the two electrode bodies, which bodies are separated from one another by an air gap or an insulating material, a coupling capacitor is formed, by which the metal tool is or can be coupled to the measuring device, to an alternating voltage source or to an electrical potential.

Abstract: The present disclosure describes an ultrasonic welding apparatus, which improves the welding strength of an electrode tab and an electrode lead included in a secondary battery, and a secondary battery with an enhanced electrode structure strength by using the ultrasonic welding apparatus. The secondary battery includes an electrode assembly in which a cathode plate provided with a cathode tab, an anode plate provided with an anode tab, and a separator are stacked in turn; a pouch for receiving the electrode assembly; a cathode lead electrically coupled to the cathode tab by welding; and an anode lead electrically coupled to the anode tab by welding, wherein the density of welding points, formed at a welding surface between the anode lead and the anode tab, is higher than that of welding points, formed at a welding surface between the cathode lead and the cathode tab.

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: The present disclosure provides a welding electrode and methods of manufacturing the same. The welding electrode can include a composite body having a tip portion and an end portion. The composite body can include a shell defining a cavity through the end portion, the shell comprising a first metal that includes one or more of the following: a precipitation hardened copper alloy, copper alloy, and carbon steel. The composite body can also include a core within the shell, the core extending through the shell from the tip portion to the cavity, the core comprising a second metal that includes dispersion strengthened copper. The core and the shell have a metallurgical bond formed from co-extrusion.

Abstract: A pressing unit presses a plurality of electrodes housed in a housing path in a housing case toward an electrode outlet port. When a lever member swings to one side, a distal end of the lever member comes to be in a first position in which the lever member covers a part of the electrode outlet port. When the lever member swings to the other side, the lever member comes to be in a second position in which the distal end exposes the electrode outlet port. A first coil spring is disposed between a proximal end of the lever member and a first side surface portion of the housing case, and biases the proximal end of the lever member to a direction away from the housing case.

Abstract: A method of resistance spot welding a steel workpiece and an aluminum or aluminum alloy (“aluminum”) workpiece together includes several steps. One step involves providing a workpiece stack-up with a steel workpiece and an aluminum workpiece. Another step involves attaching a cover over a weld face of a welding electrode. The cover is made of a metal material with an electrical resistivity that is greater than an electrical resistivity of a material of the welding electrode. Yet another step involves performing multiple individual resistance spot welds to the workpiece stack-up. The cover abuts the aluminum workpiece while the individual resistance spot welds are performed. And another step involves removing the cover from the welding electrode after the individual spot welds are performed.

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 welding assembly including a current generator, a first electrode electrically coupled to the current generator, the first electrode including a first engagement surface, a second electrode electrically coupled to the current generator, the second electrode including a second engagement surface, a width-determining fixture positioned between the first electrode and the second electrode to define a welding volume having a width, and an electrically nonconductive material positioned to electrically insulate at least one of the first electrode and the second electrode from an electrical conductor outside the width.

Abstract: A power contact for a liquid-cooled plasma arc cutting system is provided. The cutting system includes a torch body and a lower torch assembly. The power contact comprises a substantially hollow body including an upper portion and a lower portion, and an external surface of the upper portion of the hollow body configured to matingly engage the torch body. The power contact further includes a thread region disposed on an internal surface of the hollow body. The thread region is configured to retain an electrode holder of the lower torch assembly of the plasma arc cutting system to matingly engage the lower torch assembly and secure the lower torch assembly to the torch body.

Abstract: A low-cost tip dressing cutter causing no accumulation of swarf around a breaker is provided. A surface of a breaker 5 facing a cutting plate 4 corresponds to a recessed surface 52. The diameter of the recessed surface 52 gradually decreases with increasing distance from the outer periphery of the recessed surface 52 facing the cutting plate 4 in a direction opposite to the cutting plate 4. A through hole 51 is formed at the center of the breaker 5, A screw 6 inserted through the through hole 51 is screwed to a fastening hole 33a of a holder 3 to attach the cutting plate 4 to the breaker 5.

Abstract: A welding electrode for resistance spot welding includes a weld face comprising rings of ridges that project outwardly from a base surface of the weld face. The rings of ridges are positioned on the weld face to contact and impress into a sheet metal workpiece surface during resistance spot welding. If the welding electrode is used during resistance spot welding of light metal alloy workpieces, such as those of aluminum alloy or magnesium alloy, the rings of ridges on the weld face can contribute to improved welding performance.

Abstract: A method for welding a plurality of aluminum to aluminum welds and a plurality of steel to steel welds using the same welder includes providing a resistance spot welder with a pair of weld electrodes having an electrode face radius of curvature in the range between 20 mm and 40 mm. The series of aluminum to aluminum welds is first made, and then, after completing the aluminum to aluminum welds, the series of steel to steel welds are made. After completing the steel to steel welds the weld electrodes are cleaned by an abrasive to remove any buildup or contamination of aluminum on the electrodes. In the event the electrodes have mushroomed, then dressing of the electrodes is provided and then the abrasive cleaning is performed to restore the surface texture.

Abstract: A resistance welding method for welding a stack of three or more workpieces. The method includes the steps of holding a first welding tip in abutment against a first outermost workpiece, holding a second welding tip in abutment against a second outermost workpiece, and holding a pressing member in abutment against the first outermost workpiece. The method also includes the steps of gripping the stacked assembly with the first welding tip, the second welding tip, and the pressing member and passing an electric current between the first welding electrode and the second welding electrode.

Abstract: A welding electrode includes an electrode holder and an electrode cap removably attached to the holder and having a central longitudinal axis. The cap includes a body having an end, and a welding surface that is substantially smooth and free from any grooves defined therein, and has a first diameter of from about 7 to 10 mm, a first radius of curvature, and a second radius of curvature that is different from the first radius. The cap includes a skirt portion extending away from the body and configured to bear against the holder. The skirt portion has a first face that is substantially parallel to the axis and spaced apart from the surface. The body has a second face interconnecting the first face and the surface, and the body tapers from the first face to the surface. A method of forming a resistance spot weld joint is also disclosed.

Abstract: A method of forming a continuous sheet of pleated, hook-form, fastener product includes training a substrate about a pressure roll having an outer surface defining circumferential grooves. As the substrate approaches a nip between the pressure roll and a mold roll calendered with the pressure roll, a portion of the substrate is disposed within a corresponding one of the grooves between the pressure roll and a stationary horn extending into the groove whereby a longitudinally-extending pleat is formed in the substrate. The pleated substrate is then passed through the nip where resin regions are laminated to a side of the substrate opposed to the pleat.

Abstract: A method is disclosed for dressing a resistance stop welding (RSW) tip and a tip dresser apparatus. According to the method, a circumferential shoulder is cut to a predetermined depth from a distal end of the RSW tip. The shoulder is cut in the side wall to provide a reduced radius side wall and a reduced radius distal end on the RSW tip. The depth of dressing the distal end of the RSW tip is controlled by providing a stop that engages a step formed in the side wall formed by the circumferential shoulder. The tip dresser apparatus includes a first cutting blade retained by a first holder that cuts a step into the side wall to a predetermined depth. A second cutting blade retained by a second holder cuts a radiused surface on the distal end until the stop engages the step.

Abstract: A welding electrode according to the disclosure includes a body. A head is secured to the body and includes an aperture through which a pin extends. A polymer insulating sleeve is arranged between the pin and the head, for example. The sleeve material extends radially from an inner diameter to an outer diameter. The outer diameter engages the head, and the inner diameter is in close proximity to and engagement with the pin, which slides axially relative to the sleeve. The head and sleeve include first and second interlocking features that cooperate with one another to retain the sleeve in the aperture. The sleeve is arranged inboard from an outer face of the head, which is used to support a work piece.

Abstract: Method for stake-fastening an accessory (4) into a plastic fuel tank, whereby: the accessory (4) is equipped with at least one orifice (5) which passes right through the accessory (4); at least some of the plastic of which the wall of the tank (1) is made is melted; and some of the molten plastic is forced through the orifice (5) of the accessory without becoming detached from the remainder of the molten plastic; the protruding molten plastic is given an appropriate shape (8) to obtain a self-formed plastic rivet, and is left to solidify; the size and shape of the orifice (5) and/or of the solidified plastic (8) being such that the accessory (4) is mechanically fastened to the tank by at least some of the solidified plastic (8), the stake-fastening of the accessory (4) occurring at the time of manufacture of the tank (1) through the moulding of a split or at least two-part parison.

Abstract: Embodiments of the present invention are directed to an air cooled, retract-start plasma cutting torch having improved performance. The torch comprises any one, or a combination of an improved nozzle, electrode, shield cap and swirl ring, where these components have improved geometries and physical properties which optimize plasma jet performance during cutting.

Abstract: A plasma arc torch is provided that includes a tip having an improved life. The tip defines a first set of fluid passageways, a second set of fluid passageways and an internal cavity in fluid communication with the first and second fluid passageways. The internal cavity includes a base portion disposed proximate and surrounding a central orifice of the tip. A first set of fluid passageways allow for entry of a cooling fluid into the tip and a second set of fluid passageways allow for exit of the cooling fluid from the tip.

Abstract: A method is disclosed for using welding electrodes with a spherically-domed welding face having concentric contoured features formed into the face for better contact with workpiece surfaces. The concentric contoured features may be initially formed by rotating a cutting tool with a contoured cutting edge, the cutting edge being in engagement with the electrode face. A similar practice may be followed to re-create the weld face surface geometry if it becomes eroded or malformed during welding use. A suitable tool may have a blade-like geometry, with a mounting portion for supporting and positioning the tool in a rotating holder and a cutting edge. The cutting edge may have a contour complementary to that of the weld face and extend at least from the center of the weld face to at least the radial extent of the concentric contoured features.

Abstract: Methods of crack avoidance during resistance spot welding are provided. The compressive stress from the spot welding is distributed across an electrode assembly having an enlarged footprint. The electrode assembly includes a conductive core and a non-conductive cover. The delivery of current through the electrode assembly is localized to the conductive core.

Abstract: A spot welding tip for use in a spot welding machine includes a base portion having a longitudinal base axis that passes through a center of the base portion. A tip portion extends from the base portion and provides a contact surface. The tip portion includes a longitudinal tip axis that passes through a center of the tip portion and a center of the contact surface. The spot welding tip includes a transverse axis that is perpendicular to both the base axis and the tip axis. The base axis and the tip axis are parallel to one another and offset from one another by a length. The contact surface is angled with respect to the transverse axis by an angle.

Abstract: Metallic components, including superalloy components such as turbine vanes and blades, are joined or repaired by electric resistance with a high electrical resistivity brazing alloy composition. In some embodiments the brazing alloy comprises filler metal selected from the group consisting of nickel, iron, and cobalt base alloy and elements selected from the group consisting of phosphorous (P), boron (B), silicon (Si), germanium (Ge), sulfur (S), selenium (Se), carbon (C), tellurium (Te) and manganese (Mn). In performing the method of the present invention a high electrical resistivity brazing alloy composition is introduced within a substrate defect or interposed between two substrates that are to be joined. An electric current is passed through the brazing alloy until the alloy melts and bonds to the adjoining substrate. High resistivity of the brazing alloy concentrates heat generated by the current flow in the brazing alloy rather than in the substrate.

Abstract: In resistance welding, an end portion and a flange portion are welded together at contact surfaces thereof by applying a voltage between a first electrode and a second electrode while an inner casing and a main metal piece are pressed in directions toward each other. When a shearing stress due to the pressure is applied to a ceramic guide pin, the guide pin is more resistant to wear compared to a phenolic resin guide pin. In addition, a clearance is between a large-diameter portion of the guide pin and an inner surface of a guide-pin insertion hole. Accordingly, the guide pin is capable of tilting in the radial direction, so that the guide pin can tilt so as to partially absorb the shearing stress. Therefore, the guide pin is more resistant to breakage compared to a guide pin made of ceramic that is not capable of tilting.

Abstract: A coating and method of making, using, and applying the coating to protect structures from scratches and/or the undesired collection of slag and/or spatter associated with metal working processes. The coating includes a base layer and a top layer that, when applied, mitigate adhesion of weld slag to the underlying structure. The coating is also transparent such that it does not interfere with the functionality of any indicia associated with the underlying structure or device and also renders the coating suitable for use with photo-reactive or responsive sensors and/or other non-opaque structures—such as goggles, facemasks, and/or shields.

Abstract: The invention provides a switching electrode which has a small variation in resistance value even when a large amount of current is repeatedly cut off and can carry a stable amount of current even when it is continuously used. In the invention, the switching electrode is used in a switch which includes a first switching electrode tip (21) and a second switching electrode tip (22), brings the first switching electrode tip (21) and the second switching electrode tip (22) into surface contact with each other to carry a current, and separates the first switching electrode tip (21) and the second switching electrode tip (22) to cut off the current. At least one of contact surfaces of the first switching electrode tip (21) and the second switching electrode tip (22) is a flat surface having an uneven portion.

Abstract: An apparatus for resistance welding with a welder includes a heat pipe including a hollow tube and a weld electrode fitted around a portion of the heat pipe. The weld electrode and heat pipe are conductively coupled to conduct heat across an inner surface of the weld electrode.

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.