本文采用填丝热导焊的方法研究了水下激光焊接的基本物理现象,结果表明,利用气体喷嘴可形成局部干燥空间,其保护效果取决于喷嘴结构和气体流量等参数。喷嘴的外径大小对保护效果影响显著。当保护条件差时,局部干燥空间将有水浸入,导致焊缝由良好保护条件下的浅而表面光滑平整的形状变为深而表面起伏的形状。良好保护条件下的水下焊缝的力学性能和大气中一致。 In this paper, the basic physical phenomenon of underwater laser welding is studied by means of wire-bonding thermal welding. The results show that the use of gas nozzle can form local dry space, the protection effect depends on the nozzle structure and gas flow parameters. The outer diameter of the nozzle has a significant impact on the protection effect. When the protective conditions are poor, the local dry space will be immersed in water, resulting in the welds from shallow and smooth surface shape under the conditions of good protection into a deep and surface undulating shape. The mechanical properties of underwater welds under well-protected conditions are the same as those in the atmosphere.