A comprehensive review on underwater welding: methods, property evaluations and challenges

Underwater welding offers a wide range of applications in a variety of disciplines. The notion of underwater welding appeals to many in the naval construction industry since it effectively repairs colliding and damaged ships. This paper mainly focuses on the characteristics of underwater weldings, such as arc bubble behaviour, rapid cooling and underwater welded joints. The properties of bubble behaviour, its effect on process stability and process parameters that influence bubble generation are discussed. Rapid cooling is a crucial problem faced by Underwater Wet Welding (UWW). Reducing welding speed and employing induction heating techniques can control the cooling rate while welding. The influence of water flow on weld metal shows that cold cracking is directly connected to the worse mechanical characteristics of wet weld joints under various flow conditions. The mechanisms of porosity generation are investigated using slag formation, CO production, hydrogen diffusion, and short-circuiting. Weld metal porosity is reduced when the hydrogen level and CO formation are reduced. Finally, the recent developments and challenges faced in UWW and industrial applications are addressed.