Grey relational analysis, Technique for Order of Preference by Similarity to Ideal Solution and hybrid Technique combining Order of Preference by Similarity to Ideal Solution and Grey Relational Analysis are used to optimize process parameters of friction stir welded Aluminum 6061 pipes for greater tensile strength and hardness. These statistical approaches are known for solving multi objective problems where in this case, multi objective tensile strength and hardness are optimized with respect to friction stir welding parameters such as rotational speed, travel speed and tool pin diameter. The design of experiments were designed using Taguchi- L27 orthogonal array and responses such as tensile strength and hardness is evaluated for each set of parameters. The results from three statistical approaches converged to a single the optimized set of parameters – 1800 rpm rotational speed, 5 mm pin diameter and 20 mm/min travel speed.