In this study, a self-equipped temperature measuring system, included temperature detectors, data acquisition devices and a laptop PC, was used to measure the temperature changes on A6061-T6 aluminum alloys during FSW. Then, regression curves, obtained from the temperature measurement results by using the least square curve fitting method, were used to analysis the peak temperature distribution on the cross-section of the weld.The experimental results indicated that the real-time temperature measurement could be performed and recorded stably during FSW. The peak temperature on the joints is related to the perpendicular distance from the weld center, and it is little affected by the position change along the welding direction. Decreasing the distance from the weld center increases the peak temperature. If the distance from the weld center is same, the peak temperature in advancing side is higher than the peak temperature in retreating side. The peak temperature on the surface of the tool probe is estimated from the least square fitted regressive curves, it is 511.7 �Cin advancing side, and it is 421.02�C in retreating side.

Keywords: friction stir welding, weld, temperature