Effect of Tool Angle on Friction Stir Welding of Aluminum Alloy 5052: Role of Sheet Thickness

The technique of friction stir welding (FSW) does offer several advantages over conventional welding techniques. In this paper is presented the results of an investigation aimed at understanding the effect of tool angle on welding of sheets of commercially pure aluminum and aluminum alloy AA5052-H32 having different thickness. The present study demonstrates the feasibility of using friction stir welding (FSW) for joining two different thickness sheets of commercially pure aluminum (t = 1.5 mm and t = 2.0) with sheets of aluminum alloy 5052-H32 having thickness of 1.6 mm and 2 mm. It was found that the tool angle does play a major role in the welding of sheets having different thickness. Formation of the FSW zone was analyzed both macroscopically and microscopically. The tensile properties of the joints were evaluated and correlated with the formation and presence of the FSW zone. From this study it was found that the tool angle for commercially pure aluminum having a thickness of 1.5 mm and 2.0 mm is 2.580. The tool angle is 1.910 for the sheets of AA 5052-H32 having a thickness of 1.6 mm and 2 mm. The joint efficiency of the friction stir welded AA 5052-H32 was 87.5 pct. when compared to the base material. The hardness was also observed to drop in the region of the weld. Key words: Friction stir welding, tool angle, aluminum alloy (AA5052-H32), Hardness, macrostructure, microstructure