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Abstract

— Friction Stir Welding (FSW) is a solid state welding process in which the relative motion between the tool and the work piece produces heat which makes the material of two edges being joined by plastic atomic diffusion. This method relies on the direct conversion of mechanical energy to thermal energy to form the weld without the application of heat from conventional source. The rotational speed of the tools, the axial pressure and welding speed and the (weld time) are the principal variables that are controlled in order to provide the necessary combination of heat and pressure to form the weld. These parameters are adjusted so that the interface is heated into the plastic temperature range (plastic state) where welding can take place. During the last stage of welding process, atomic diffusion occurs while the interfaces are in contact, allowing metallurgical bond to form between the two materials. The functional behavior of the weldments is substantially determined by the nature of the weld strength characterized by the tensile strength, metallurgical behavior, surface roughness, weld hardness and micro hardness. Al alloy is difficult to weld by traditional methods, due to high thermal conductivity, resulting in defects like porosity, cracks etc. Hence FSW is being increasingly used. The process is especially well suited to butt and lap joint in aluminium since aluminium is difficult to weld by arc process, but is very simple to weld by FSW. In this project the process parameters are to be varied in order to determine and evaluate the influence of the process parameter in the quality of the weldments. Friction stir welding machine is used to be carried out the experiment using AA6061 & AA6082 Aluminium Alloy material. The output factors to be measured using destructive methods. Tensile test, Hardness test and Microstructure of Welded Region are considered for investigation by varying tool speed, tool feed and maintaining constant depth of penetration of weld. The correlation between process parameters and quality of the weld to be analyzed in friction stir welding process and compared with other welding process or techniques. (Abstract)

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