激光-MAG复合焊熔质分布与熔池流动特征

Behaviors of element density distribution and melting metal flow in CO_2 laser-MAG hybrid welding

采用扫描电子显微镜和高速摄像机分析了CO2激光-MAG电弧复合焊接焊缝中熔质元素的分布规律,以及复合焊熔池的形成过程与熔池内熔质分布的关系.熔质分布与熔池的流动状况及元素添加位置密切相关,其决定因素是激光与电弧两热源间距变化引起的熔池流动特征变化.激光匙孔强烈的波动和熔体紊流可以使熔质分布均匀化,但低熔点金属形成的等离子蒸气冲击力会使熔质在焊缝中形成局部区过度富积,而激光束流的扫描和搅拌可进一步促使熔质元素分布均匀化.当光丝距离为3 mm、元素添加位置距表面1.0 mm时,熔池中添加元素含量较高并且分布最为均匀.

The distributions of the elements in CO2 laser-metal active gas(MAG) hybrid welding were investigated with scanning electron microscope.The relation between the forming process of weld and the distribution of the element in CO2 laser-MAG hybrid welding process was analysed with high-speed camera and scanning electron microscope.Both the melting metal flow and position of adding elements decide the element distributions.Metal flow varies due to changes of DLA(distance between laser and arc).The fluctuation of the keyhole can promote the uniform distribution of the element,but the impactness of the metal vapour enriches element in local zone of welding pool.The scanning and stiring of laser beam further make the uniform element distribution.The highest content and uniform distribution of elements can be obtained in the molten pool when the distance between laser and arc is 3 mm and elements are added from the location 1.0 mm away from the surface.