An experimental investigation was carried out to comprehend the impact of speed of traverse of tool on tensile strength and micro-structural peculiarities of attained joints during friction stir welding of Cu alloy namely CDA 101 flat plates, with other parameters namely spinning speed of tool (1100 rpm) and downward force (6kN) being constant. A tool with cylindrical tapered pin geometry was made to traverse at distinctive speeds from 20 mm/min to 45 mm/min. It was observed that, the CDA 101 joints fabricated at 20 mm/min was found to be entirely free flaws, with joints fabricated at other speeds of tool traverse possessing several weld flaws. Grains in the center of the zone of stir of the joints obtained at 20 mm/min was uniformly distributed and homogeneous, due to the experience of the exemplary volume of frictional heat and sufficient amount of stirring force. Highest tensile strength of 200.65 MPa (nearly 85.38% of base metal) was exhibited by joint attained at 20 mm/min