Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2012.1026.1031KarthikeyanP. MahadevanK. 1020121210Friction stir welding process is used for joining materials such as aluminium, copper, magnesium etc., which are otherwise difficult to weld by the conventional welding processes. In friction stir welding, the tool profile plays a critical role in determining the end properties of the welded joint apart from the other parameters like rotational speed, welding speed and axial load. The aim of the present investigation was to compare the weld quality of the AA6063 plates joined using the square and the pentagonal friction stir welding tool profiles. From the test results it is observed that the square pin tool profile has yielded a good weld bead structure along with superior strength and hardness when compared with the pentagonal tool profile.]]>Thomas, W.M.,19911991Mishra, R.S. and Z.Y. Ma,200550178Elangovan, K. and V. Balasubramanian,200829362373Elangovan, K. and V. Balasubramanian,2007A459718Karthikeyan, P. and K. Mahadeven,20102010Minton, T. and D.J. Mynors,2006177336339Kim, Y.G., H. Fujii, T. Tsumura, T. Komazaki and K. Nakata,20066038303837Balasubramanian, V.,2008A480397403Elangovan, K. and V. Balasubramanian,2008200163175