An Improved FSW Tool for Joining Commercial Aluminum Plates

Abstract

This paper presents the experimental findings of friction stir welding (FSW) on commercial aluminum plates of 6.5mm thickness using a newly developed improved flat pin tool with side radius and its comparison with standard 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 400rpm to 1400rpm, at a constant feed rate i.e., at 30mm/min for making comparison between the newly developed flat pin tool and the standard straight threaded pin tool. The comparative study indicates that, the newly developed tool produces the better tensile strength than the standard straight threaded tool in the entire range of the tool rotational speeds. The maximum strength of the FSW joints is 78% of that of its base metal at 400rpm using the new tool. It is further observed that, for both the tools, the 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.