| 摘要 |
A friction stir welding method that can prevent the center of a welding part from being unwelded is provided. In a friction stir welding method comprising lapping a plurality of members over one another, and rotating a welding tool(1) and pressing the welding tool into one of the members, thereby causing friction stir to weld the members, the friction stir welding method is characterized in that a bulging part(2) having a small diameter positioned at a front end of a shoulder(3) of the welding tool is disposed at an outer peripheral side out of a rotating axis of the welding tool. The bulging part is formed in a semispherical shape. The bulging part has a tangent line formed in an angle range of 45 to 90 degrees relative to the rotating axis of the welding tool. The welding tool has a plurality of bulging parts at the shoulder thereof. The bulging part is formed in an elliptical shape. |
