In the present work, the friction stir welding is applied on a three aluminum alloys that are AA1050-H12, AA 5754-24 and AA 7075 to investigate the effect of weld pitch on the mechanical properties and peak temperature. The friction stir welding are performed at weld speeds of 100, 300, and 500 mm/min. In all cases, the applied rotation speed is 600 rpm. A variation in the mechanical behavior of the welded alloys is observed. The UTS increases with increasing the weld pitch for the strain hardening alloys AA 1050 and AA 5754. A dramatic decrease of UTS with increasing the weld pitch is predominant for AA 7075. A maximum joint efficiency (tensile percentage) of 94 % is attained for AA5754 at faster weld pitch of 0.83 mm/rev whereas the minimum joint efficiency of 61.4% is a share of AA 7075-T6 at slower weld pitch of 0.17 mm/rev. A different hardness profiles are obtained for the experienced alloys and different strengthening mechanisms are discussed for result explanation.