EXPERIMENTAL STUDY OF EFFECT ON DIFFERENT TOOL ROTATIONAL AND TRANSVERSE SPEED FOR UNDERWATER FRICTION STIR WELDING (UFSW) OF AA 5083 ALUMINUM ALLOY

Abstract

Friction Stir Welding (FSW) is an advanced solid state joining process to join metals without reaching its melting point. The quality and strength of the joint is dependent on welding conditions such as tool rotational, transverse speed and tool geometry to generate the required amount of heat during the process. This research conducted to study and obtains the suitable rotational and transverse speed for the best quality of joining by the UFSW. The research involved in design and fabricated the customized fixture to retrofit the support system on the table of the universal milling machine for conducting the experiments. The experiment was conducted in underwater and dry condition with different tool rotational and transverse speed. The objectives of this research are to study and investigate the effect of the different temperature produced during the welding process on the quality of the joining in underwater condition. The result from this research indicated the temperature distribution and properties of AA 5083 welded specimens are highly influenced by UFSW method. It is also shown the influence of the water tends to decrease the heat input and thus avoiding the deterioration of the mechanical properties of the joint. Hence, by controlling the tool rotational and transverse speed, the joint can achieve good mechanical properties without creating any defect. It is also found that the combination of the tool rotational and transverse speeds 1700 RPM @ 67mm/min exhibited superior mechanical and tensile properties for UFSW. Besides, the fracture location ofUFSW was found in Weld Nugget Zone (WNZ) while the FSW fracture location was found in Heat Affected Zone (HAZ). In addition to that, the microstructure of these two methods also has the differences as the grain size in UFSW is much smaller compared to the FSW in each region.