Patent ID: 8167188

Claim:
A friction stir welding method, comprising: providing a joining tool comprising a friction surface; providing a first workpiece comprising a first treating surface, a first joining surface, and an inclined connecting surface joining the first treating surface and the first joining surface; providing a second workpiece comprising a second treating surface, a second joining surface, and an inclined connecting surface joining the second treating surface and the second joining surface; providing a joining tool comprising a friction surface for rubbing and stirring the first treating surface and the second treating surface, wherein the joining tool is substantially cylindrical, and the friction surface is formed at a bottom end of the joining tool; arranging the first workpiece and the second workpiece such that the first joining surface abuts the second joining surface, and the connecting surface of the first workpiece and the connecting surface of the second workpiece cooperatively define a slot facing the joining tool, and the width of the friction surface is larger than that of the slot; positioning the friction surface of the joining tool to resist at least one of the first treating surface and the second treating surface; and rotating and moving the joining tool to rub and stir the first treating surface of the first workpiece and the second treating surface of the second workpiece by the friction surface, until at least part of the first workpiece and the second workpiece are plasticized and joined together, wherein during rubbing and stirring of the first workpiece and second workpiece, some plasticized material flows into and fills the slot.