What Is Underwater Welding?
Underwater welding, also known as hyperbaric welding, is used to repair submerged metal structures without removing them from the water. This is done through several different processes: some dry, whereby water is pumped away from the area; and some wet, where the welder, using specialist equipment, must weld through the water. Underwater welders must also be skilled divers and able to work at extreme depths and water pressure.
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History
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Underwater welding was first invented in Russia in 1932 by Konstantin Konstantinovich Khrenov and used throughout the Soviet navy. During World War II, the American Cyril D. Jensen, professor of engineering at Lehigh University, developed the USA's own underwater welding program and created two U.S. patents in the field.
Welding Sites
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According to technology site TWI, the majority of underwater welding is used to repair offshore oil platforms which may have been damaged by hurricanes or explosions. It is also used to repair submerged pipelines, the hulls of steel ships and other harbor work. By repairing steel work without moving it to dry land, underwater welding saves companies millions of dollars every year.
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Process
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According to Welding Advisers, there are three main ways to perform an underwater weld. The first is a dry weld, whereby an enclosure is built around the area that needs to be repaired and the water is replaced with air until the area is the same pressure as a normal surface weld. Welding then takes place under normal dry conditions. The second method also uses an enclosure but filled with helium to push the water out of the area. The welder wears breathing equipment and completes a dry weld. The third method is a wet weld which uses an arc welder to blast the welding line with a gas mixture which allows the weld to dry instantly without being hampered by the water. For this the welder must also be a qualified scuba diver and use specially designed equipment to prevent electric shock.
Careers
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If you want a career in underwater welding, according to the American Welding Society (AWS), you must have qualifications in commercial diving and understand deep water diving and specialist commercial diving equipment. You must also have DS standard AWS qualifications in welding to prove that you are a certified welder. With these two qualifications you can start looking for work with Diving Contractors. However, once you are employed most companies will ask you to complete a D3.6, Specification for Underwater Welding to prove you can do the work before you start the job. However, each company has its own policies.
Risks
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According to site Welding Advisers, the main risk to underwater welders is electric shock. If the electric arc welder is in some way faulty, the current could travel through the water and electrocute the welder. In addition, if during the weld the arc produces pockets of oxygen and nitrogen which then mix, there is a possibility of an explosion. Other hazards to underwater welders include nitrogen narcosis (a drunken feeling) if the diver has been welding at extreme depths for too long and an effect known in the diving community as "the bends," small bubbles of nitrogen in the blood which can be fatal. They are caused by returning to the surface too quickly without giving your body enough time to eliminate the gas from your blood stream through decompression.
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References
Resources
- Photo Credit welding image by glgec from Fotolia.com
