6061 aluminum tubing is an aluminum alloy can be heat strengthened superhard materials, cast convenience, good formability, has a good overall performance. As the weld often generate pores, cracks when welding aluminum, undercuts and other defects, especially for ultra-high-strength aluminum alloy heat strengthened its arc welding worse, prone to hot cracking, a serious impediment to the 6061- T6 aluminum tubes used in industry. Friction stir welding (FSW) as an efficient, high-quality, environmentally friendly, low-cost new welding method for high-strength 7xxx series aluminum alloy can be welded well. This paper selects 6061-T6 aluminum plate 8mm Single pass butt friction stir welding experiment, and the microstructure and mechanical properties of joints were analyzed.Welding test materials used for 8mm thick 6061-T6 aluminum, stirring head material used H13 hot work die steel. Chemical etching solution is 15ml HCl + 1ml HF + 2.5ml HNO3 + 95ml H2O; organizing feature in Optelics TMS 130 was observed under a microscope weld zone; tensile tests on CSS-44100 electronic universal testing machine; in the HX-1000 Microscopy durometer hardness measuring.
Weld nugget zone occurs continuous dynamic recrystallization form fine equiaxed; heat affected zone in the role of mechanical forces and thermal cycling was strip arc organization; organization grain HAZ coarsened. When speed is 375r / min, welding speed of 100mm / min, the joint highest tensile strength can be achieved by 88.6% of the base material. Weld hardness distribution presents “W” shape, the minimum basic occurs at the transition back side heat affected zone and heat affected zone