Weld electrode for attractive weld appearance

A welding electrode for forming electrical resistance spot welds in an assembly of overlying metal workpieces that comprises at least one aluminum alloy workpiece, the welding electrode comprising:

• a body;
• a spherically rounded weld face at one end of the body, the spherically rounded weld face having a radius of curvature between 20 mm and 50 mm;
• and
• ringed protrusions that project outwardly from the spherically rounded weld face and are positioned to make contact with and indent into a surface of the aluminum alloy workpiece when the convex weld face of the welding electrode is brought into contact with the assembly of overlying sheet metal workpieces during a resistance spot welding operation, the ringed protrusions being radially spaced from one another and each of the ringed protrusions having a circumference that surrounds a center of the convex weld face.

A welding electrode for forming electrical resistance spot welds in an assembly of overlying metal workpieces that comprises at least one aluminum alloy workpiece, the welding electrode comprising:

• a body;
• a convex weld face at one end of the body;
• and
• ringed protrusions that project outwardly from the convex weld face and are positioned to make contact with and indent into a surface of the aluminum alloy workpiece when the convex weld face of the welding electrode is brought into contact with the assembly of overlying sheet metal workpieces during a resistance spot welding operation, the ringed protrusions being radially separated from one another by portions of the convex weld face and each of the ringed protrusions having a circumference that surrounds a center of the convex weld face, and wherein an amount of area of the convex weld face modified by the ringed protrusions is 50% or less of a contacting area of the convex weld face.