6005A铝合金型材搅拌摩擦焊未焊合缺陷的搅拌摩擦补焊研究

Repairing of penetration defect for 6005A aluminum by friction stir welding

搅拌摩擦焊未焊合缺陷多存在于焊缝根部,在受力加载时极易产生应力集中,进而发生破坏。首先选用不同针长的搅拌头在轨道车辆常用的6005A铝合金型材基体上,进行不同长度尺寸根部未焊合缺陷的制备。在此基础上,研究了搅拌摩擦焊接方法对上述不同未焊合缺陷的补焊效果。试验结果表明,在一定工艺参数下,通过改变搅拌头针长尺寸可以制备不同长度尺寸的未焊合缺陷。并通过焊缝表面成形、内部成形以及原始未焊合缺陷所在位置的微观组织和拉伸测试分析表明,未焊合缺陷尺寸越大对应的焊缝拉伸性能越低。但不同尺寸的未焊合缺陷在经过搅拌摩擦补焊后都能完全消失,且补焊接头性能与最优搅拌摩擦焊接头的性能相当,证明了搅拌摩擦补焊方法对于消除未焊合缺陷的有效可行性。

Incomplete penetration in friction stir welding is a serious defect,which normally lead to stress concentration. In this paper,different size incomplete penetration defects were fabricated by adjusting the pin length of the tool on 6005A aluminum alloy extrude profile,and then friction stir repair welding technology focusing on the weld morphology and mechanical properties of the repaired joints were studied. The experimental results indicated that when the FSW parameters were constant,different size incomplete penetration defects could be fabricated by changing the length of FSW tool,which means that FSW incomplete penetration defect intimate related with pin length of FSW tool. The friction stir repair welding process could remove incomplete penetration defect,and the repaired joints had good weld morphology and excellent mechanical properties.