This research focused on studying the influence of friction stir welding (FSW) factors-such as the type of the welding tool, the speed of the welding tool and the welding speed-on the impact toughness of the panels made of AA6061-T6 aluminum alloy sheets with thickness of 3mm. The aluminum alloys have multiple uses in industry, but are quite difficult to be welded by fusion welding processes, including MIG welding, and laser welding. By using a milling machine, it was possible to employ the FSW process, applying four constant welding speeds (800, 1000, 1250, 1600 rpm) and three welding speeds (32, 63, 80 mm/min). Tool pins with square cylindrical and threaded tapered cylindrical profiles were used in the experimental programme. The machined samples were subjected to Charpy V notch impact test at room temperature and the results were compared to the impact energy of the base metal. The results show higher values of the impact energy when the tool pin used has square profile.