Combined stirring head capable of improving quality of surface of friction stir welding connector

The invention discloses a combined stirring head capable of improving the quality of the surface of a friction stir welding connector. The combined stirring head comprises a static shaft shoulder and a stirring needle. The stirring needle is composed of a stirring needle body and a stirring needle root. A lower end face is machined at the lower portion of the static shaft shoulder, wherein an included angle ranging from 3 degrees to 10 degrees is formed between the cross section of the static shaft shoulder and the lower end face. An arc containing groove is machined in the side, inclined relative to the axis of the stirring needle, of the lower end face. A large-diameter fillet is machined at the contact position of the arc containing groove and a workpiece. The stirring needle body and the stirring needle root are connected in a threaded manner and are arranged in the static shaft shoulder. The stirring needle root is exposed out of the lower end face of the static shaft shoulder. By means of the combined stirring head capable of improving the quality of the surface of the friction stir welding connector, the defects of arc lines, trimming, sunken parts and the like generated on the connector in the friction stir welding process can be effectively overcome; and scratches generated in the grinding process can be effectively reduced, the smoothness degree of the connector is improved, the mechanical performance of the connector is improved, and the material utilization rate is increased.