Tool design and process analysis of bobbing tool friction stir welding for thin-walled extrude profile of 6061-T6 aluminum alloy

An engineering model between characteristic value of welding tool and specimen thickness was established based on heat input theoretical analysis of bobbing tool friction stir welding. According to this model, a welding tool was designed and optimized, which was used for join 2.5 mm thin-walled extrude profile of 6061-T6 aluminum alloy. Friction stir welding parameters were optimized as well. When the rotation speed of the tool was 1 000 r/min and welding speed was 600 mm/min, the joint obtained a maximum mechanical properties. The front side joint had a tensile strength of 231 MPa, 77% of the base material, and a bend angle of 180°, while the back side joint had a tensile strength of 226 MPa, 76% of the base material, and a bend angle of 180°.