| Friction stir welding (FSW) is a newly developed technology. It not only has the advantage of traditional friction welding but also breaks the limitation of traditional friction welding which only can weld cylindrical member. Not only straight weld seam but also various kinds of joints in different position can be welded by FSW. However, FSW is the patent technology of TWI. In the related papers, the content about parameter of FSW and friction stir tools is scarce. As known to us all, Al is widely used in production. Therefore, in order to catch up with the advanced technological level, it is imminent and difficult to use new FSW technology in the joint of Al plate, realize the optimization of FSW parameter and estimation of joint quality.In this paper, design of friction stir welding tool, performance of friction stir welding joints, friction stir welding parameter, SN plan and analysis, superplastic behavior of joints based are particularly discussed. The regulation of friction stir tool, performance of friction stir welding joints, friction stir weld parameter is obtained. To the LF21 which is 3mm in thickness, the form of the stir has been improved is conic which has concave at the bottom; the parameter of the best techniques are 1500rpm 37.5mm/min, 1500N.Good joint is obtained by setting parameter to get plastic state in the past. The superplastic deformation has low stress, enough deformation which is suitable for materials process.This paper will discuss the superplastic behavior of the fiction stir welding joint to choose proper parameters in which superplastic state can be obtained to get good joint. The highest rate of the prolongation has been obtained is 91% at 450°C with the tensile speed of 0.6mm/min. It can be concluded primarily, superplastic property may appear at about 450°C,however ,these need further research. The results of the research can be used in parameter optimization of FSW and accelerate the application of FSW in colored metal in our nation. |
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