Comparative study of friction stir welding and tungsten inert gas welding of pure aluminum

This paper presents the experimental findings of FSW on pure aluminum plates of 6.5 mm thickness using straight threaded pin tool with flat collar made of hardened steel. The effect of FSW is studied on hardness, strength, toughness and microstructure with different tool rotational speeds ranging from 400 rpm to 1400 rpm, at a constant feed rate i.e., at 30 mm/min and the findings are compared with a conventional joining process, Tungsten Inert Gas (TIG) weld specimen. The comparative study indicates that, the tensile strength of the FSW joints is 78% of that of its base metal when tool rotation speed is at 400 rpm, which happens to be the double the strength of single side TIG welded specimen. And, it is further observed that, in case of FSW, hardness of weld zone is increased at lower tool rotational speed, while refined microstructure can be noticed on surface of the weld zone at higher tool rotational speed.