Underwater Welders

There are two main types of underwater welding: wet underwater welding and dry underwater welding.

In wet underwater welding, welders use specialized electrodes that operate under submerged conditions. They work directly in the water without any protection from the elements (other than a diving helmet and suit). Welders use electric arc welding techniques in their work, specifically, shielded metal arc welding and flux-cored arc welding. There is no physical barrier between the welding arc and the water. “Wet welding relies on the release of gaseous bubbles around an electric arc to shield the weld and prevent any electricity being conducted through the water,” according to The Welding Institute. “This insulating layer of bubbles protects the diver but also obscures the welding area, making it harder to complete the weld correctly.” Underwater welders work in open waters that may be 300 feet deep. These welders must be excellent divers to safely descend to and work in these great depths. A saturation diver is a welder who is qualified to descend to and work at depths of up to 1,000 feet below the surface. Wet underwater welding is often used to make emergency repairs, but such repairs may have reduced weld quality due to water contamination and hydrogen embrittlement.

In dry underwater welding, welders work in hyperbaric chambers (specially built, pressurized dry enclosures) or cofferdams (structures that are built in water that remove water from a certain area). Since the welding area is protected from water, welders can use traditional welding techniques and equipment in their work. The most common dry welding methods are gas tungsten arc welding, gas metal arc welding, flux-cored arc welding, and shielded metal arc welding. Dry underwater welding is safer than wet welding, and the welds that are created are of a higher quality. But this type of underwater welding is more expensive and requires more set up time than wet welding does.

Robotic welding systems (RWSs) are increasingly being used for underwater welding projects that require high-quality welds—such as on offshore oil platforms, underwater pipelines, and ship hulls. The use of RWSs reduces injury risk to human welders. This technology is expected to augment, but not replace, the work of underwater welders. Human welders will still be needed to program and monitor RWSs, and there are many settings in which these systems cannot be used.