||In this study, friction stir spot welding and friction stir welding (FSW) experiments were conducted under a friction stir welding machine with constant load. The welding tools are small embedded-type tool and plain tool. The welding characteristics and the welding mechanism of aluminum alloy sheets are investigated under different operating conditions, such as the normal load (100~580 N), the rotation speed (6000~12000 rpm), and the welding speed (0~4 mm/s). |
Effects of welding times, normal loads, and rotation speeds on the depression depth, the plastic flow depth, and the ultimate load of the welded workpiece are investigated for the spot welding, to obtain the relationship between the depression depth and the ultimate load. By the results, the welding quality of embedded-type tool is better than the plain tool, the ultimate load increased about 2.3 times.
Based on the results of spot welding, two best experimental conditions are selected to conduct the FSW experiments. Results show that the embedded type of welding tool with 9000 rpm for a large mass of flash was found due to the excess heat input of joint. To overcome this defect, the heat input should be decreased to obtain smooth surface and stable welding quality.