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采用三角平面圆锥形搅拌针焊接20mm厚的铝板,分析工艺参数对焊缝成形及金属流动特征影响。随着旋转速度增加,单位时间内金属迁移量增大,焊核区面积增加,疏松区面积减小至消失;而过大的旋转速度反而使疏松缺陷再次出现。适当减小焊接速度,增大单位长度内焊缝热输入,改善焊缝成形,但焊接速度过小易导致焊缝上部受热过多,疏松区及内部孔洞变大。在合适的参数下焊接时,瞬时空腔的出现可使更多塑化金属绕搅拌针做圆周迁移,即提高了沿水平方向的“抽吸-挤压”效应,改善了金属流动性,减少甚至消除焊缝内部缺陷。
A 20 mm thick aluminum plate was welded by a triangular flat conical pin to analyze the influence of the process parameters on the weld formation and the metal flow characteristics. With the increase of rotating speed, the amount of metal migration per unit time increased, the area of weld nugget increased, and the area of loose zone decreased to disappear. However, the oversized rotating speed caused the reappearance of loose defect. Properly reduce the welding speed, increase the heat input per unit length of the weld to improve the weld shape, but the welding speed is too small easily lead to excessive heat weld, porosity and internal holes become larger. The presence of an instantaneous cavity allows more plasticized metal to migrate around the pin when welded under the appropriate parameters, increasing the “suction-squeeze” effect in the horizontal direction and improving the metal’s fluidity , Reduce or even eliminate the internal defects of the weld.