Abstract
AA5083 is an alloy of military-grade aluminum used to make lightweight combat vehicles. Combining this material with traditional welding methods results in the formation of grain agglomerations, alloy separation, porosity, and pores. To overcome these shortcomings, Friction stir welding was utilized. In this work, the problems arising from friction stir welding are reduced by performing the process underwater. A relative study was also conducted to determine the impact of various tool pin profiles. particularly straight hexagonal, straight cylindrical, straight threaded, and tapered cylindrical. Friction stir welding and Underwater friction stir welding were used for welding Aluminium alloy AA5083 alloys of 150 x100 × 6 mm, constant tool rotational speed of 1200 rpm, tool transverse speed of 40 mm/min, and tool tilt angle of 0°. This study revealed that the straight hexagonal pin produced joint in an underwater cooling medium had a greater tensile strength (UTS) of 295 MPa and a joint efficiency of 78 %.