Friction Stir Welding of 6061 Aluminum Alloy with Diferent Pin Tools and Rotation Speed

Abstract

Joining aluminum alloy by fusion welding usually creates many problems because the heat melting point leads to aluminum oxides which prevent the joining process. This is because metals oxide acts as on heat insulter in addition to the problems of microstructure such as solidification cracks, void, porosity, slag inclusion and poor mechanical properties. Thus, friction stir welding is considered the best method to weld aluminum alloys because of joined low temperature, no of solidification and no filler metal or flux used. These results in good properties in joint and recrystallizing in the stir zone. In this work the mechanical properties (tensile strength, microhardness and impact strength) of 6061 aluminum alloys with different pin tool (cylindrical threaded pin SCT, tapered cylindrical threaded pin TCT and triangular threaded pin TT) and different rotation speeds (450, 560 and 900)RPM at constant welding speed (35mm/min) has been stud-ied .The results show that the microstructure is very fine and homogenous with all tools, super tensile strength using TCT tool at rotation speed (560RPM) equals to (370MPa),in additions hardness has in-creased but still lower than of base metals .The impact strength has also increased with all the tools com-pared to that of base metals.