Abstract: An aluminum plate (103) is overlaid on a steel plate (102). A distal end (113) of a button component (101) is pushed in from the obverse surface side of the aluminum plate (103), and the distal end (113) is abutted against the steel plate (102) by applying a first pressure to the button component (101) made of steel without heating. The distal end (113) of the button component (101) and the steel plate (102) are welded by resistance spot welding while applying a second pressure lower than the first pressure to the button component (101).

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. The multiple stages include: (1) a molten weld pool growth stage in which a molten weld pool is initiated and grown within the aluminum-based workpiece; (2) a molten weld pool solidification stage in which the molten weld pool is allowed to cool and solidify into a weld nugget that forms all or part of a weld joint; (3) a weld nugget re-melting stage in which at least a portion of the weld nugget is re-melted; and (4) a re-melted weld nugget solidification stage in which the re-melted portion of the weld nugget is allowed to cool and solidify.

Abstract: When spot-welding a workpiece including a thin plate, a first thick plate, and a second thick plate, the workpiece is clamped by a fixed electrode in contact with the second thick plate, a movable electrode in contact with the thin plate, and control-pressure applying unit set adjacent to the movable electrode and in contact with the thin plate. Pressure is applied to the second thick plate by the fixed electrode, and pressure and control pressure are respectively applied by the movable electrode and the control-pressure applying unit to the thin plate. The pressure from the fixed electrode is controlled to be smaller than the pressure from the movable electrode. The current density between the thin plate and the first thick plate increases.

Abstract: A process for joining, by spark plasma sintering, at least two refractory ceramic parts, each of the parts having at least one surface to be joined by spark plasma sintering, in which surfaces to be joined are brought into contact without addition of any sort between the surfaces. Then, a joining pressure of 1 to 200 MPa is applied to the ceramic parts. A pulsed electric current having an intensity of 500 A to 8000 A is applied to the ceramic parts so as to raise the temperature of the parts to a joining temperature of at least 1300° C. Then, the electric current is terminated simultaneously with the pressure, and the parts are cooled, and the joined parts are recovered.

Abstract: The joining method includes a step of lapping the aluminum alloy plate and the plated steel plate via adhesive, a pre-heating step of clamping both metal plates lapped in the lapping step between a pair of electrodes for spot welding and applying pressure thereto, and applying a current between the pair of electrodes, a cooling step of pressurizing both metal plates at a pressing force higher than that at the start of the pre-heating step in a state where conduction between the electrodes is stopped, and continuing this pressurization over a predetermined cooling time, and a welding step of pressurizing both metal plates at a pressing force higher than that at the start of the pre-heating step, and welding both of the metal plates by applying a current higher than the conduction current value in the pre-heating step between the pair of electrodes.

Abstract: A visually seamless method of joining a first piece of metal and a second piece of metal is described. The first piece of metal is placed in contact with an edge of the second piece of metal. In some embodiments, the edge includes a sacrificial lip. The first piece of metal forming a junction area with the edge of the second piece of metal, applying a forging force to the first piece of metal, the forging force having an effect of creating an extremely tight fit up between the first and the second pieces of metal, welding the first and the second pieces to form an assembly and forming a cosmetically enhancing protective layer on the surface of the assembly, the protective layer obscuring any visible artifacts on the surface of the assembly, the obscured visible artifacts including any discoloration or discontinuity created by the laser welding.

Abstract: A one-sided spot welding device having a concentrically arranged weld electrode assembly and an electromagnet for clamping together and holding metallic parts during a one-sided spot welding process. A device of the present invention may include a mounting base having a central weld electrode and an outer, concentrically arranged weld electrode extending therefrom. The outer weld electrode may surround or partially surround the central electrode, with some gap therebetween. The central electrode is associated with an actuator that is provided to press a tip of the central weld electrode against a metal component to be welded. An electromagnet resides between the central and outer weld electrodes of the electrode assembly to draw metal components into tight abutting contact and to hold the components in contact with the outer weld electrode during welding.

Abstract: A resistance welding apparatus includes a welding gun having a first electrode tip serving as a first welding electrode, a second electrode tip serving as a second welding electrode, and a current branching electrode. The current branching electrode has an annular shape and is disposed in surrounding relation to the first electrode tip. The first electrode tip and the current branching electrode abut against a thinnest workpiece disposed on an outermost side of a stacked assembly that is resistance-welded by the resistance welding apparatus, and have opposite polarities to each other. When an electric current is passed from the first electrode tip to the second electrode tip and through the stacked assembly, a branched electric current flows from the first electrode tip to the current branching electrode.

Abstract: The joining method of the present invention includes a lapping step of lapping the aluminum alloy plate (1) and the plated steel plate (2) via the adhesive (5), a pre-heating step of clamping both of the metal plates (1, 2) that have been lapped in the lapping step between a pair of electrodes (7, 7) for spot welding and applying pressure thereto, and applying a current between the pair of electrodes (7, 7), a cooling step of pressurizing, after the pre-heating step, both of the metal plates (1, 2) at a pressing force which is higher than that at the start of the pre-heating step in a state where conduction between the electrodes (7, 7) is stopped, and continuing this pressurization over a predetermined cooling time, and a welding step of pressurizing, after the cooling step, both of the metal plates (1, 2) at a pressing force which is higher than that at the start of the pre-heating step, and welding both of the metal plates (1, 2) by applying a current which is higher than the conduction current value in th

Abstract: An improved spot welding system for clamping and welding a plurality of workpieces at predetermined datum locations includes a clamping element, and at least one electrode. The preferred electrode(s) and element are concentrically alignable during engagement, and configured to produce an annular weld about the datum location. More preferably, the workpieces define an opening at the datum location, the element includes an insulated pin at least a portion of which is configured to pass-through the opening, and the electrode defines an inner space configured to receive the portion of the pin, when the electrode and element fully engage the workpieces.

Abstract: An improved apparatus and method for the prevention of deformation and buckling of metal plates during welding processes is disclosed. The improved apparatus and method are used to apply pressure to a welded seam created between two metal plates during the welding process. Pressure is applied to the area of the plates surrounding the welded seam until the welded seam has sufficiently cooled to prevent deformation and buckling of the metal plates.

Abstract: A device for mutually connecting by laser welding of sheet-metal objects laid flat against each other at least in determined zones, for instance two or more flat or previously profiled plates, for instance stainless steel or other objects for mutual connection by laser welding, comprising: a welding station comprising a laser and an optical device for performing a laser welding operation using a laser beam via a preselected path consisting for instance of a plurality of sub-paths; clamping means, for instance a lower clamping plate and an upper clamping beam for clamping against each other at least said regions, of the objects at the location of the welding station; transporting means for supplying and carrying successive assemblies of objects laid on top of each other according to a chosen displacement pattern along the welding station, which transporting means comprise two separate conveyors, wherein the welding station is a collective one for both conveyors and respective individual clamping means are adde