Effect of boric acid on metal transfer mode of underwater flux-cored wire wet welding

For obtaining high quality of underwater welding repairing for nuclear power equipments, the influence of boric acid on metal transfer process of underwater flux-cored wire wet welding in boric acid solution is explored by an X-ray transmission system. The research results show that the mixed repelled globular transfer and solid short circuit transfer mode and the mixed repelled globular transfer and surface tension transfer mode are two kinds of main metal transfer modes during underwater welding in boric acid solution. The proportion of the mixed repelled globular transfer and surface tension transfer mode is increasing with the increasing of concentration of boric acid solution, which is caused by the difference of force condition of the droplet.