Stirrer used for friction stir welding of aluminum alloy

The utility model discloses a tool used for friction stir welding, in particular relates to a stirrer suitable for being used for friction stir welding of aluminum alloy with the thickness of 25 millimeters or more. The stirrer used for friction stir welding of aluminum alloy comprises a clamping part, a shaft shoulder and a stirring needle, wherein the inward inclining angle Alpha of a shaft shoulder end surface formed at the connection part between the shaft shoulder and the stirring needle is equal to 10 to 20 degrees, and the stirring needle is tapered and provided with tapered threads on the surface. The stirrer used for friction stir welding of aluminum alloy has the following benefits: 1. aluminum alloy with the thickness of 25 millimeters or more can be welded, and no air pore is caused in weld joint structures; 2. the welding deformation is small, and the weld joints have attractive appearance; 3. the operating environment is friendly; 4. the connector is impact-resistant and fatigue-resistant; and 5