Yes, you read the heading correct underwater welding, but how is it possible for water welders to weld underwater because in welding, electricity plays the major role and we all know that electricity and water can’t go hand in hand. Underwater welding process is undoubtedly a dangerous process, but with proper training and following safety rules, risks can be avoided. Underwater welding was invented in 1930s which is used for maintenance and repairing full or partial submerged marine structures. Now the underwater welding can be differentiated into two inland weldings where the work on dams, bridges & small seacraft is done and another one is offshore welding which is done on ships, undersea pipelines, underwater habitat, oil rigs, etc.
There are two types of underwater welding, the first one is dry welding and the other is wet welding. In dry welding the welders creates a seal first around the area where the welding process is going to take place, then the water is pushed out with the help of high-pressure pumps through hoses and the gaseous mixture of helium and oxygen takes the place. Then the right amount of pressure is created to prevent the chamber from decompression sickness after that the divers cum welders choose which welding method can be applied according to the size of chambers. There are few welding methods that are applied on dry welding which are dry spot welding, dry chamber welding, habitat welding, pressure welding, GTAW/TIG, GMAW/MIG and plasma arc welding.
Wet welding as it is clear by its name that water is going involved in this process, but what about the current? As a reader you must be thinking that how the divers don’t get an electric shock, here a layer of gaseous bubbles are generated when the arc melts the flux, this layer shields the weld and prevents electricity from being conducted beyond itself. These bubbles secure the welding area and can disturb the weld pool if the diver cum welder is not careful. Direct current (DC) is a popular way to weld. For underwater welding, it is considered safe as compared to alternating current. SMAW is the common welding method applied in wet welding but flux-cored arc welding (FCAW) and friction welding are also employed for underwater welding.