Stirring head for optimizing friction stir welding seam S line

The stirring head for optimizing the friction stir welding seam S line comprises a clamping handle, a transition section and a stirring needle which are sequentially connected from top to bottom along a rotating shaft, a shaft shoulder is formed on the lower end face of the transition section, a groove used for disturbing a base material oxidation film is formed in the side wall of the stirring needle, the edge of the groove is sharp, and the groove is asymmetrically distributed along the rotating shaft. The groove is formed in the stirring needle, so that the oxidation film can be crushed through the groove, oxidation film particles formed by crushing are irregularly dispersed into a welding seam, and the probability of forming a thick, large and continuous S line is reduced. 本发明公开了一种优化搅拌摩擦焊焊缝S线的搅拌头，包括沿旋转轴从上至下依次相连的夹持柄、过渡段和搅拌针，过渡段的下端面形成轴肩，搅拌针的侧壁开设有用于扰动母材氧化膜的槽，槽的边缘锐利，且沿旋转轴呈非对称式分布。通过在搅拌针上开设槽，从而能够利用槽对氧化膜进行破碎并将破碎形成的氧化膜颗粒物无规律地分散至焊缝中，进而降低形成粗大、连续的S线的概率。