Abstract: A projection coined onto a metal sheet, preferably an aluminum sheet, for projection welding the sheet to an adjacent metal sheet. The projection has a thickness greater than the thickness of the sheet on which it is formed. The wall of the projection surrounds a first recess and a second recess is formed in a side of the sheet opposite the projection from which the metal cold flows to form the projection. A welding gun assembly having an improved low interia, fast response to the collapse of the projection welding the sheet having the projection to the adjacent sheet.

Abstract: A projection coined onto a metal sheet, preferably an aluminum sheet, for projection welding the sheet to an adjacent metal sheet. The projection has a thickness greater than the thickness of the sheet on which it is formed. The wall of the projection surrounds a first recess and a second recess is formed in a side of the sheet opposite the projection from which the metal cold flows to form the projection. A welding gun assembly having an improved low interia, fast response to the collapse of the projection welding the sheet having the projection to the adjacent sheet.

Abstract: A modification of the electrode geometry for resistance spot welding of aluminum. A ratio of the surface area of the weld nugget to the surface area of the electrode face is about 0.75 to about 1. The diameter of the electrode face is smaller than the industry recommended size and which provides higher current density and reduces the amount of power needed for welding aluminum.

Abstract: A projection coined onto a metal sheet, preferably an aluminum sheet, for projection welding the sheet to an adjacent metal sheet. The projection has a thickness greater than the thickness of the sheet on which it is formed. The wall of the projection surrounds a first recess and a second recess is formed in a side of the sheet opposite the projection from which the metal cold flows to form the projection. A welding gun assembly having an improved low interia, fast response to the collapse of the projection welding the sheet having the projection to the adjacent sheet.

Abstract: A projection coined onto a metal sheet, preferably an aluminum sheet, for projection welding the sheet to an adjacent metal sheet. The projection has a thickness greater than the thickness of the sheet on which it is formed. The wall of the projection surrounds a first recess and a second recess is formed in a side of the sheet opposite the projection from which the metal cold flows to form the projection. A welding gun assembly having an improved low interia, fast response to the collapse of the projection welding the sheet having the projection to the adjacent sheet.

Abstract: A method for welding together two workpieces includes the steps of abutting workpieces together along respective edges of each of the workpieces, and locating one end of a rotatable tool astride the edges and against the workpieces. The tool is provided with a relatively narrow pin extending from the working end of the tool to engage the workpiece edges. The tool and pin are rotated to heat the workpiece edges, and the tool and workpieces are relatively moved. Electric current is supplied between the workpiece edges and the pin, with electrical resistance occurring between the workpiece edges and pin to provide heat in addition to the heat generated by friction occurring between the pin and workpieces to weld the workpieces together.

Abstract: A method and apparatus for graining a surface having a substantial area traveling at a substantial rate of speed. The method includes directing the surface past an array of electrical arcs traveling about a plurality of loop electrodes arranged to provide overlapping arc loop paths as the surface travels past the array of arc loops. The arc loops are established between the loop electrodes and the traveling surface, and thus contact the surface to grain the same. When each arc is struck between its loop electrodes and traveling surface, it is magnetically impelled about the loop of its electrode by a magnetic field established perpendicular of the direction of arc current flow. An annular sheath of gas is provided on each side of the electrode loop and the arc struck between the electrode loop and the traveling surface.