Electrode for spot welding

An electrode for forming electrical resistance spot welds in any of a steel workpiece, an aluminum alloy workpiece, or a magnesium alloy workpiece, the electrode comprising a body with a dome face at one end of the body for engagement with a surface of the workpiece being welded, the dome face comprising:

• a dome face surface;
• a round plateau centered on the dome face surface, the round plateau having a plateau surface raised above the dome face surface and a circumference such that the dome face surface surrounds the round plateau, wherein the dome face surface and the plateau surface, taken together, define an overall spherical radius of curvature of the dome face, and wherein the plateau surface is planar or has a spherical radius of curvature that is greater than the overall spherical radius of curvature of the dome face;
• and
• at least one surface feature elevated above or depressed below the dome face surface;
• wherein the round plateau is sized and shaped to contact and indent into a steel alloy workpiece to form electrical resistance spot welds in the steel alloy workpiece and the combination of the round plateau and the at least one surface feature is sized, shaped, and located to contact and indent into an aluminum alloy workpiece or a magnesium alloy workpiece to form electrical resistance spot welds in the aluminum alloy workpiece or the magnesium alloy workpiece.