Patent ID: 8927894
Filing Date: 2015-01-06
Classification: B23K,C21D

Abstract:
1. A method of forming one or more electrical resistance spot welds in an assembly of overlying metal workpieces, the method comprising: pressing a spherically rounded welding face of a welding electrode against an outer surface of an assembly of overlying metal workpieces, the spherically rounded welding face being pressed against an aluminum alloy workpiece, which is part of the assembly, and having a radius of curvature between 20 mm and 50 mm, the spherically rounded welding face comprising concentric circular rings of ridges that are formed on, and extend outwardly from, the spherically rounded welding face and contact the aluminum alloy workpiece against which the spherically rounded welding face is pressed, each of the concentric circular rings of ridges further having a constant rounded cross-sectional profile; pressing a welding face of another welding electrode against an outer surface of the assembly of overlying metal workpieces opposite the spherically rounded welding face; and passing an electrical current between the welding electrodes through the assembly of metal workpieces to form a weld nugget between the metal workpieces and to deform the outer surface of the aluminum alloy workpiece against which the spherically rounded welding face is pressed so that a weld site image is formed as an obverse shape of the concentric circular rings of ridges on the spherically rounded welding face.