Study of Mechanical Properties Change During Friction Stir Spot Welding of Aluminium Alloys

The Friction Stir Welding process is now 20 years old and the interest in it and its potential continues to increase dramatically. FSW can be applied to a multitude of products with varying material types and thicknesses. However, a continuous weld is not always required to meet the product performance requirements. Thus, one can consider some form of intermittent weld, such as Friction Stir Spot Welding. Friction Stir Spot Welding (FSSW) can be considered for many of the applications presently performed with traditional resistance spot welding (RSW), the basic concept of FSSW is remarkably simple. A non-consumable rotating tool with a specially designed pin and shoulder is inserted into the abutting edges of sheets or plates to be joined the tool serves two primary functions: (a) heating of work-piece, and (b) movement of material around pin to produce the joint. The heating is accomplished by friction between the tool and the work-piece and plastic deformation of work piece. The localized heating softens the material around the pin and combination of tool rotation and axial load. As a result of this process a joint is produced in ‘solid state’. From using this method to perform the Welding tests were performed using two welding parameters and the welds were sectioned and evaluated using optical microscopy. Mechanical testing of the spot joints was performed utilizing the tension-shear configuration. And also evaluate the hardness on the weld spot at the different zone nugget, TMAZ, HAZ and Base plate.