Friction stir welding was a promising welding technology from the same moment of its existence because of its easy use, being ecologically friendly processed and with no need for filler metal. The present paper discusses the investigate the mechanical properties in order to demonstrate the feasibility of friction stir welding for joining Al 6061 aluminum alloy welding was performed on pipe. The pipe sections, 30mm, and relatively thin walled 2, 3 and 4 mm. Wire welded as similar alloy joints using (FSW) process In order to investigate the effect of rotation speed 485,710, 910, 1120,1400 and 1800 RPM and travel speeds 4, 8 and 10 mm/min. On mechanical propertie. This work also focuses on mathematic models such as regression analysis (RA) to predict the tensile strength, the percentage of elongation and hardness of friction stir welded 6061 aluminum alloy. The Tensile strength, the percentage of elongation and hardness of weld joints were predicted by taking the parameters Tool rotation speed, material thickness and travel speed as a function. The results obtained through regresion analysis The models have been proved to be successful in terms of agreement with experimental results ratio 94.6%.