The Effect of Welding Speed on the Root Flow of Plastically Metal by Friction Stir Weld of 2219 Aluminum Alloy

The butt joining of 2219 Aluminum was carried out by using friction stir welding with different welding speed. The pattern of root flow of friction stir welding was analyzed under different conditions through labeling material. The results show that, when other conditions are constant, it is easy to produce cavities on the advance side of root weld with the increase of weld speed. There is no cavity when the weld speed is 75HT7 HT5"mm/min. With the increase of weld speed, the sucking-extruding effect weakened and the drive force of root plastic metal flow decreased. However, the resistance of plastic flow increased which leading to the range of plastic metal flow decreased.