Patent ID: 7455212

Claim:
A friction stir weld process of joining work pieces using a rotary friction stir welding apparatus comprising a die having an aperture adapted to receive a cylindrical, shouldered rotary tool, said die further comprising a recessed portion defining an inlet zone adapted to accommodate a filler material, the process comprising the steps of: placing a filler material on and about a joint line formed by butting a first work piece surface against a second work piece surface by inserting the filler material into the inlet zone of the die; and frictionally heating the filler material by placing the die over the joint line to soften the filler material and portions of the first and second work piece surfaces in thermal contact with the filler material and form a weld between the first and second work pieces, wherein frictionally heating is at a temperature below a melting point of the filler material and the first and second workpiece surfaces.