Friction based Solid State Welding Techniques for Transportation Industry Applications

Solid bonding based processes represent an effective solution in terms of both joints mechanical performances and sustainability. In the last years, both the academic and the industrial researchers focused their work on two solid-state processes: Friction Stir Welding (FSW) and Linear Friction Welding (LFW). The former, patented in 1991 by TWI, is used to weld sheet metal in different joint morphologies, i.e. butt, lap T and 3D joints. The latter has been known for several years, but a growing interest is observed in the last years due to the enhancement of the welding machines performances. LFW, used to join bulk components, is particularly suited for aeronautical and aerospace applications.In this paper, the potential of the two processes is investigated analysing the joints properties and the metallurgical modifications induced by the processes as related to the welded alloy. For both the processes, the effect of the main process variables is highlighted and the impact on industrial production is pointed out.