Classification of metal transfer mode in underwater wet welding

The metal transfer process of underwater flux-cored wet welding with a water depth of 0.5 m is observed using an x-ray transmission method for arc voltages from 24 to 46 V and a welding current from 237 to 440 A. Four fundamental metal transfer modes are found: the globular repelled transfer mode, the surface tension transfer mode, the explosive short-circuit transfer mode, and the "submerged arc transfer mode," while the explosive short-circuit transfer mode is rarely observed. In contrast to onshore welding, the metal transfer mode of underwater wet welding is a mixed transfer mode rather than a single transfer mode; this mode mainly consists of two or more fundamental metal transfer modes, including the globular repelled transfer mode, the surface tension transfer mode, and the "submerged arc transfer mode." The proportion of the fundamental transfer modes constituting the mixed transfer mode changes with variations in the welding current and arc voltage. The mixed mode is divided into four types according to the different categories of fundamental modes in the mixed mode, as represented by a transfer mode map. The metal transfer process of underwater wet welding is unstable, necessitating control by adjusting the composition of welding materials or improvement in the properties of welding equipment.