Abstract: The Zaxis loads were measured in the process of 6082T6 aluminum alloy refill friction stir spot welding and the influence of different welding parameters(shaft shoulder rotate speed， stirring pin rotate speed， tying into/withdrawing time and tying into depth， etc.)on loads was studied. The results show that curve of loads in the process of aluminum alloy refill friction stir spot welding can be divided into 4 zones: clamp ring pushing process， shaft shoulder tying into process， stirring pin refill process and stirring tool unloading process. Loads in the test reduce fluctuation as the rotating speed of shaft shoulder or stirring pin increases. Loads in the test reduce gradually as the shoulder tying into/withdrawing time increases. Loads in the test fluctuate without showing a trend as the shoulder tying into depth increases.

Key words: refill friction stir spot welding, aluminum alloy, rotate speed, load, tying into depth