US Patent 10183356 Welding tool comprising a shoulder, welding method and workpiece

A welding method for connecting at least two workpieces at a connection region by means of friction stir welding using a welding tool having a probe and a shoulder. The method includes rotating the probe around a rotation axis, wherein the connection region is softened by friction heat provided by the probe during said friction stir welding to form a welded seam at the connection region. The method also includes molding, simultaneously with forming the welded seam, at least one of a bevel, a rounding and a chamfer on an edge of the connection region using the shoulder, wherein the shoulder is configured to separate the connection region from the surroundings.