Abstract: Friction stir welding is a solid state joining method of welding invented in 1991 at The Welding Institute that utilizes a non-consumable rotating welding tool to generate frictional heat and plastic deformation.FSW can be used to join difficult to join materials like aluminium alloys, copper, magnesium, zinc, steels, and titanium.This technique overcomes difficulties of fusion welding.FSW found applications in the automobile, aerospace, marine, defence and medical industries. The control parameters rotational speed, axial load, tool geometry, welds speed affects quality of weld obtained. The advantages of Friction stir welding (FSW) are no fumes; uses no filler material; and low cost of operation. FSW sometimes produces a weld that is stronger than the base material.FSW is considerably ecofriendly than conventional "fusion" welding. In this paper, review of state of art, working principle, welding of different materials, work piece material applications etc are presented.

Keywords: Solid State Joining.