Patent ID: 7857191

Claim:
A method of welding first and second workpieces to one another by friction stir welding (FSW) comprising the steps of: (a) providing a first workpiece having mutually orthogonal structural components and a junction region therebetween which defines a bearing surface having an arcuately concave geometry; (b) bringing one of the planar structural components of the first workpiece into adjacent contact with a surface of a second workpiece; (c) providing a FSW tool having a shoulder which defines an arcuately convex geometry which is conformably mateable with the arcuately concave geometry of the bearing surface, and a pin extending from the shoulder; and (d) welding the first and second workpieces to one another by bringing the shoulder of the FSW tool into bearing contact with the bearing surface at the junction region between the mutually orthogonal structural components of the first workpiece and advancing the pin extending from the shoulder of the FSW tool into and through the one structural component of the first workpiece at an angular orientation relative thereto so as to thereby form a friction stir weld region between the first and second workpieces.