The friction stir welding of small-diameter pipe: an experimental and numerical proof of concept for automation and manufacturing

Friction stir welding (FSW) is a powerful joining process which is limited by its range of application and processing rate. Here the range of application is extended to small-diameter butted pipe sections and high processing rates are applied for increased productivity in manufacturing. Full penetration friction stir welds are performed on butted sections of aluminium alloy 6061-T6 pipe. These pipe sections are relatively small in diameter (4.2 inches) and relatively thin walled (0.2 inches). The small radius of curvature distinguishes this weld configuration geometrically from a butted plate configuration and presents unique challenges. This work confronts these challenges using experimental and numerical methods. An FSW process method producing acceptable pipe joints is demonstrated.