The friction flow spot welding experiment has been performed on 1mm thick aluminum alloy 6061-T6.The process

microstructure and properties of welded joints were analyzed. The results show that the welded joints can be divided into four regions namely weld nugget zone

thermo-mechanical affected zone

heat affected zone and base material zone. The weld nugget zone has the tiniest grains. Down force

welding rotational speed and welding time have influences on the properties of the welded joints. In this paper

the author selects down force as the parameter for controlling the plunge depth of the tool. When down force ≤ 2300N

the hooking defeat hasn't inserted into the top surface of the upper sheet

the fracture mode acts as the “shear fracture”. When down force 2300N

the fracture mode acts as the “plug fracture”.The study shows that when choosing down force 2300N

welding rotational speed 2000r/min

welding time 10s as the welding parameter

good weld joints of 1mm thick aluminum alloy 6061-T6 can be got.