Transient Thermal Analysis of Friction Stir Welding using 3D-Analytical Model of Stir Zone

Friction Stir Welding is a solid state joining method with five phases of actions in its entire process. The first is the plunging period, where the pin is fully and shoulder is partially plunged into the joint line of the work piece. The second action is in the dwell period during which the tool keeps on rotating at the plunge point. In this phase the material around the tool is heated due to the friction between the probe and matrix surfaces due to sliding action. Due to this thermo-mechanical action, materials around the tool get plasticized. The third phase of action is in the steady state welding period, during which the rotating tool is traversed along the welding line. This is followed by a second dwell period, which is the fourth phase of action. The last and the fifth phase of action is in the releasing period during which the rotating tool is raised up from the weld line leaving behind a pin cavity in the work piece. In the FSW model of William the metal flow zones are categorized as shoulder zone, extrusion zone and vortex swirl zone, and these zones are defined using regular geometries. In this present study shoulder zone and the vortex swirl zone are defined same as William’s model. But the extrusion zone has been defined using more accurate geometry and based on Askari’s concepts a combined analytical and finite element based model has been developed for thermal distribution analysis of FSW process and the thermal history in the Stir zone, Heat affected zone and the base metal has been determined. Experimental Procedures