الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Friction Stir Welding (FSW) is a solid state welding process investigated by Wayne Thomas at 1991. This welding process is environmentally friendly, highly repetitive and easily adjusted to manufacturing geometries. New welding techniques are being continuously developed for materials that are difficult to join by traditional methods such as fusion welding.A specially designed rotating tool that includes of a pin and shoulder that have dimensions proportional to the plate thickness is used. The plates are rigidity clamped on the machine table and the tool fix into the machine spindle. The pin of the rotating tool is plunged into the plate material and the shoulder comes into contact with the surface of the plate, and then traverses in the welding direction. The contact between the rotating tool and the plate generate heat which softens the material below the melting point of the sheet and with the mechanical stirring caused by the pin, the material within the processed zone undergoes intense plastic deformation yielding a dynamically-recrystallized fine grain microstructure.In this work, FSW is used to weld two plates of Aluminum alloy 5052-H111 butt joint at different rotational and welding speeds. Stepped and tapered pin profile tools are used with pin diameter (d) is 5 mm and a shoulder diameter (D) is 15 mm while the pin length is kept constant at 4.8mm. The welding conditions such as the Welding Speed (W.S), the Rotational Speed (R.S), Tool Tilting Angle (T.A) (ranges) and the tool design are studied to identify the highest effect of parameters. Design of Experiment is planned by Minitab17. Multi-response optimization has been performed based on Taguchi-method to optimize the welding parameters. Ultimate Tensile Strength and Micro-hardness are measured as the two-responses to predict the optimal parameters for the welded joints.