STUDY OF RELATION BETWEEN PIN TOOL GEOMETRY WITH FORMATION OF WORMHOLE IN FSW OF ALUMINUM AA5083

Friction Stir Welding has developed as alternative machinery for joining metallic alloys
that can be consider as almost impossible to join with conventional techniques. FSW
process is employed for joining low melting point metal in several industries such as
aerospace, rail, automotive and marine industries. Presence of cavity defect or wormhole
is a common occurrence in Friction Stir Welding that been closely linked to weaken the
joint mechanical properties. Formation of cavity at stirred area or nugget is a result of
poor flow control of plasticize welding material, hence understanding movement of
plasticize material is crucial to dictate the problem. Variables such as pin tool geometry,
tilting angle and also direction of pin tool rotation are believed to impact the flow of
melted workpiece. Nevertheless, frictional contact conditions at the tool–workpiece
interface, the resulting microstructure, and the genesis of the cyclic variation in process
responses are among the issues that need elucidation from critical experimentations.
This project proposes pin tool design to reduce size of wormhole spawn from FSW
process. Manipulative variables that were tested were pin tool geometry, and pin tool
material. The experiment was conducted at room temperature on controlled test-piece
dimension of Aluminum 5083. Parts of mechanical properties of the welded samples
and also microstructure formation will be presented to conclude the study.
Keywords: Friction Stir Welding, wormhole size, pin tool geometry, pin tool material,
aluminium 5083