Abstract
Lap joints of 6061 aluminium alloys were obtained using friction stir welding. The welding parameters used are: rotational speed, welding speed and pin Length. There were two levels of each factor involved. Rotational speed levels were 900 and 1120 rpm, welding speed levels were 1 and 1.5 mm/sec and pin length levels were 4.5 and 5.5 mm. Successful lap joints were produced for the different combinations of the above welding parameters. The joints quality tested under tensile testing and the microstructure of the welding zone were studied. Fracture mostly occurred in the base metal for most lap-shear welded joints. The exception was joints with welding parameters as follows: rotational speed 900 rpm, the welding speed 1.5 mm/sec and pin length 4.5 mm. In this case, the fracture occurred in the welding zone.