Patent ID: 7455211
Filing Date: 2008-11-25
Classification: B23K,Y10T

Abstract:
1. A method of friction stir welding a workpiece, the method comprising: rotating a friction stir welding pin in a first rotational direction and urging the friction stir welding pin in a first direction against the workpiece to thereby plasticize a portion of the workpiece and form a first-pass friction stir weld joint therein defining an advancing side and a retreating side; and rotating the friction stir welding pin in a second rotational direction opposite the first rotational direction and urging the friction stir welding pin in the first direction against the workpiece to thereby plasticize a portion of the workpiece and form a second-pass friction stir weld joint therein at least partially substantially parallel to the first-pass friction stir weld joint, the second-pass friction stir weld joint defining an advancing side and a retreating side, wherein the second-pass friction stir weld joint only partially overlaps the first-pass friction stir weld joint, the second-pass friction stir weld joint at least partially overlapping the retreating side of the first-pass friction stir weld joint without entirely overlapping the advancing side of the first-pass friction stir weld joint such that the first-pass and second-pass friction stir weld joints form a multi-pass friction stir weld joint, wherein a portion of the second-pass friction stir weld joint is outside the first-pass friction stir weld joint.