微束等离子弧焊三维焊接堆垛过程塌陷

Study on the collapse of 3D welding stacking process by micro plasma arc welding

采用搭建的三维运动平台对微束等离子弧焊三维焊接堆垛过程中收弧位置塌陷问题进行了研究,利用CCD相机实时跟踪拍摄整个三维焊接堆垛过程,在此基础上分析了堆垛过程中的熔池流动和熔滴过渡变化,并分析了熔池所受作用力及焊接工艺参数对塌陷的影响.结果表明,收弧位置堆垛墙体下塌是由于被挤压到熔池尾部的液态金属来不及回流以及焊丝最后的熔滴未过渡到熔池中导致填充金属不足、熔覆金属的流淌造成的,且随着堆垛墙体收弧端的下塌量累积,熔滴不能稳定过渡到熔池中,进一步加剧了堆垛墙体在收弧端的塌陷,从而使得三维焊接堆垛过程难以继续.

The collapse of three dimensional welding stacking in the end portion of the weld pass was studied by micro plasma arc welding on the 3D motion platform. 3D welding stacking pocess was tracked in real time by using a CCD camera.The change of the weld pool and the droplet transferring were observed and analyzed. The influence of welding force and welding parameters on the collapse was investigated. Experimental results showed that the reasons of the collapse in the end portion of the weld pass include the flow of molten metal and the lack of the filler metal due to the fact the liquid metal pressed to the rear end of the weld pool,which can not be returned and the last molten droplet on the wire is not transfer to the weld pool. Especially,the accumulation of sinking in the end of stacking wall resulted in the droplet not transfer stably to the molten pool,and it makes the collapse further exacerbate. As the result,3D welding stacking process is hardly continued.