Patent ID: 7628876

Claim:
A method of making a welded metallurgical bond in an automotive assembly comprising a first metal sheet-polymer layer-second metal sheet laminate and a metal workpiece to be bonded to the second metal sheet of the laminate, the method comprising: providing the automotive assembly comprising the first metal sheet-polymer layer-second metal sheet laminate and the metal workpiece; pressing a rotating tool against the automotive assembly at a predetermined location on the first metal sheet of the laminate to heat the contacted metal to a plasticized condition, the tool being sized and shaped to form a weld between the laminate and the metal workpiece at the location; continuing to press the rotating tool against the automotive assembly to successively plasticize, stir and penetrate engaged metal of the first and second metal sheets of the laminate and engaged metal of the metal workpiece through at least a portion of the thickness of the metal workpiece, and to displace the polymer layer; and retracting the tool, the plasticized metal of the two sheets and of the metal workpiece coalescing to form a weld between the two metal sheets and the metal workpiece, wherein the weld consists essentially of the plasticized metal of the two sheets and of the metal workpiece.