Friction Stir Welding of dissimilar aluminum alloys

Abstract

Friction Stir Welding (FSW) is the most important process developed in the field of welding during last decade of twentieth century. FSW is Solid State welding technique which allows metals to be welded below melting temperature. Heat input required for FSW is very less as compared to other welding processes such as TIG, MIG etc. The mechanical properties of weld produced by FSW are not highly different from its base metals. FSW technique is applied to various alloys of aluminum and high quality weld is obtained. Joining aluminum alloys of different series is difficult task due to difference between properties but FSW has enabled them to weld with good results. In FSW rotating tool comprising of probe and shoulder plunges into workpiece and traverse along a weldment line. Heat is generated both due to friction between tool shoulder and workpiece and plastic deformation. This study applies the Taguchi method to investigate the relationship between the ultimate tensile strength, Impact Strength and process variables in a friction stir welding of joining dissimilar 6061-T651 and 5083- H321 aluminum alloys. The effects of various welding parameters including Welding Speed, Traverse speed and Tool probe shape were studied. The experimental results show that the Traverse speed is most influencing parameter in both the quality characteristics. Other important finding is that the heat input is found to be in strong relation with tool welding speed. Optimal Welding speed, Traverse rate and tool probe shape for both Tensile Strength and impact strength are 1000 rpm, 10mm/min and hexagonal probe respectively.