Through what I have learned in my research, there are two types of underwater welding. The only difference is that the welding environment—dry and wet. Welding on the bottom of the sea “in the dry” but under many atmospheres of pressure is called hyperbaric welding. Hyperbaric welding takes place in a specially constructed positive pressure enclosure and hence a dry environment. On the other hand, underwater welding is working directly exposed to the underwater environment. These application are often used to repair ships, offshore oil platforms, and pipelines.
The first ever underwater welding was carried out by British Admiralty – Dockyard for sealing leaking ship rivets below the water line. Underwater welding is an important tool for underwater fabrication works. In 1946, special waterproof electrodes were developed in Holland by ‘Van der Willingen’. In recent years the number of offshore structures including oil drilling rigs, pipelines, platforms are being installed significantly. Some of these structures will experience failures of its elements during normal usage and during unpredicted occurrences like storms, collisions. Any repair method will require the use of underwater welding. Underwater welding has been used as an wet welding technique for a long time and is still being used. With the construction innovation of offshore structures, underwater welding has assumed increased importance. This has led to the development of alternative welding methods like friction welding, explosive welding, and stud welding. But these processes have insufficient theory component to be taught in classroom.
The principle of underwater welding procedure takes in the manner where the work to be welded is connected to one side of an electric circuit, and a metal electrode to the other side. These two parts of the circuit are brought together, and then separated slightly. The electric current jumps the gap and causes a sustained spark (arc), which melts...