EXPERIMENTAL ANALYSIS OF FSW FOR DISSIMILAR ALUMINIUM ALLOYS AA7075 AND AA3014 USING CNC VMC

Abstract

Friction Stir Welding process (FSW) is a solid state welding process in which the relative motion between
the tool and the work piece produces heat which makes the material of two edges being joined by plastic atomic
diffusion. This method relies on the direct conversion of mechanical energy to thermal energy to form the weld
without the application of heat from conventional sources. The rotational speed of the tools, the axial pressure,
welding speed and the tool profile are the principal variables that need to be controlled in order to provide combined
heat and pressure to form the weld. The scope of this investigation is to evaluate the effect of joining parameter on the
mechanical properties of dissimilar aluminium alloys AA3104 and AA7075 joints produced by Friction Stir welding
using CNC vertical machining centre. The Brinnel hardness and tensile strength of the joints are considered for the
investigation. The results show that for optimal stir zone hardness, FSW parameter combination of 1200 rpm tool
rotational speed, 10 mm/min welding speed and cylindrical tool profile should be used. For optimal joint tensile
strength, the suitable parameters combination is 1200rpm, 20mm/min and taper thread tool profile. From the
investigation, it is concluded that tool rotational speed is the major influencing factor for mechanical properties such
as tensile strength and hardness.