Underwater Welding

Underwater Welding

NYCO produce this technology for welding to cover all welding  process in different environments ,this technology used in offshore welding, platforms , ship repairs and all underwater construction activities.

Under water welding  is the process of welding at elevated pressures, normally underwater Hyperbaric welding can either take place wet in the water itself or dry inside a specially constructed positive pressure enclosure and hence a dry environment. It is predominantly referred to as "hyperbaric welding" when used in a dry environment, and "underwater welding" when in a wet environment.

We have all facilities (Equipment, Qualified welders and divers , Consumables , Mobile workshop, PPE, Communication and monitoring system )to cover all the requested work. 

1. WET WELDING 

Wet Welding indicates that welding is performed underwater, directly exposed to the wet environment. A special electrode (waterproofed ) is used and welding is carried out manually just as one does in open air welding.

The power source should be a direct current machine rated at 300 or 400 amperes. Motor generator welding machines are most often used for underwater welding in the wet.

Wet underwater MMA welding has now been widely used for many years in the repair of offshore platforms. Using this technic ensure:

1.  The versatility and low cost of wet welding makes this method highly desirable.
2.  Other benefits include the speed. With which the operation is carried out.
3.  It is less costly compared to dry welding.
4.  The welder can reach portions of offshore structures that could not be welded using other methods.
5.  No enclosures are needed and no time is lost building

2. Hyperbaric Welding (dry welding)

Hyperbaric welding is carried out in chamber sealed around the structure to be welded. The chamber is filled with a gas (commonly helium containing 0.5 bar of oxygen) at the prevailing pressure. The habitat is sealed onto the pipeline and filled with a breathable mixture of helium and oxygen, at or slightly above the ambient pressure at which the welding is to take place. This method produces high-quality weld joints that meet X ray and code requirements. The gas tungsten arc welding process is employed for this process. The area under the floor of the Habitat is open to water. Thus the welding is done in the dry but at the hydrostatic pressure of the sea water surrounding the Habitat.

Using this technic ensure

1. Welder/Diver Safety – Welding is performed in a chamber, immune to ocean currents and marine animals. The warm, dry habitat is well illuminated and has its own environmental control system (ECS).

2. Good Quality Welds – This method has ability to produce welds of quality comparable to open air welds because water is no longer present to quench the weld and H2 level is much lower than wet welds.

3. Surface Monitoring – Joint preparation, pipe alignment, NDT inspection, etc. are monitored visually.

4. Non-Destructive Testing (NDT) – NDT is also facilitated by the dry habitat environment.