Effect of tool material on mechanical properties of friction stir welded dissimilar aluminium joints

Frictional stir welding (FSW) is a solid-state welding process. FSW has many advantages over giving high quality welds; it is environmentally friendly and maintained with low operating cost etc. It is used to join high strength aluminium and its alloys, which are difficult to weld using conventional fusion welding and use a tool that cannot be used to join without two facing work pieces without melting of the work piece material. The mix of material flow conditions specifically affects the quality of the weld, so tool material and geometry are very important. High quality welding comes from using the right tool design with efficient processing parameters. The development of cost-effective and durable tools that lead to structurally sound welds is still awaited. Improper selection of welding parameters can cause defects in the welding joints. This FSW technique requires specific parameters to produce a defect-free joint. The parameters involved in FSW joint are tool design, tool rotation speed, tool material, axial force, transverse speeds, tilt angle and plunge depth. This paper mainly depends on how the change in tool material affects the mechanical properties of the welded joint by maintaining constant spindle speed and feed rate. Aluminium alloys are selected 6061-T6 and 6082-T6. Tool materials selected are H13, D2 and SS316 grade. Mechanical properties are evaluated by Tensile Test, Hardness Test and Charpy Impact Test through Destructive Testing. Results conclude that if the application requires toughness and hardness as major property then D2 tool material can be used for producing FSW joint and if the application requires tensile strength as major property then H13 tool material can be used for producing FSW joint.