August 3rd, 2007 
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Welding is an unavoidable process of modern engineering – civil, electrical, mechanical, automobiles, marine aeronautical – in all branches. It is used in fabrications and erections in infrastructures and installations. It joins metals or thermoplastics. Forming a pool of molten mass – the weld puddle – and allowing it to cool to become a strong joint is the basis of the process of welding. For repairing to be carried out underwater, there is a separate process. That is called underwater welding. If damaged ships are to be repaired, underwater welding is the basic technology to be used. It is a highly-specialized profession – more employed in the oil or shipping industry and also in the defense operations.
Underwater welding process is categorized into two divisions.
• Wet welding
• Dry welding
Wet welding:
In the case of wet welding, the operation is completed under water, directly exposed to the wet environment. For this purpose, a different type of electrode is used. The function is carried out manually. The welder is allowed to have freedom of movement. Hence, wet welding is the most effective, efficient and economical process.
The welding power and supply unit is placed on the surface and is connected to the welder with the help of cables and hoses.
The Advantages:
• The expenditure is very minimal. Unlike in the case of dry welding.
• The speed of the operation is extremely high.
• As the equipments are very minimum, the welding can be performed in a shorter time with minimal planning.
The Disadvantages:
• The weld is quenched is very fast under water. It decreases the ductility and impact strength an also makes the weld very porous.
• The visibility of the Welder is not up to the required level.
• The amount of voltage that can b employed is very limited. Care has to be taken so that the welder is not harmed by probable electrical shocks.
Dry Welding:
In case of dry welding, otherwise known as Hyperbaric welding, the whole operation is completed in a chamber, sealed around the structure to be welded. The chamber is filled with gas – normally helium – containing 0.5 bar oxygen. The chamber is fitted onto the pipeline and is filled with the breathable mixture of air. The operation is carried out in higher pressure. The gas tungsten arc welding process is used.
The Advantages:
• Welding can be carried out without getting affected by ocean currents and marine animals.
• Better quality welds can be used.
• From the surface itself, there is a possibility of visually monitoring joint preparation and pipe alignment.
The Disadvantages:
• The chamber is very complex. Large support equipment is needed at the surface to support the chamber.
• The expense will be very high. The cost increases proportionately to the depth under water.
• The chamber has limited reusability.
Risks & Precautions:
Both the welder and the structure are at risk. The welder has to protect himself from electric shocks. The welder has to be insulated. The voltage of the welding sets has to be controlled. Pockets of oxygen and hydrogen built up by the arc will be potentially explosive. The welder has to take precaution because nitrogen will be built up in the blood stream of the welder, when exposed to air at high pressure under the water surface. Inspection, although very difficult, is a mandatory requirement. No defects should remain. In addition to all these precautions, safe arc-welding precautions are to be taken.
Underwater welding is mostly employed in marine engineering products – in installations of oil and gas rigs. Underwater welding can be classified depending upon the types of equipments and the types of procedures involved. The most common underwater welding process, known as manual metal arc building (MMA), is employed for deep water repairing activities. Cofferdam welding process and Hyperbaric welding process are normally carried out for underwater welding operations. They are employed for welding steel pipelines, other offshore structures, submerged parts of large ships and underwater structures supporting a harbor. The safety measures include emergency air or gas supply, stand-by divers and decompression chambers.
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About Author
Brayan Peter is an expert author for Welder, Plasma Cutter, Welders, Tig Welding. He written many articles like Plasma Cutters, Welding Equipment, Plasma Cutting Machine, Arc Welder, MIG Welder, Welding Machines, Diesel Generators, Welding Helmets . For more information visit our site http://www.everlastgenerators.com. Contact him at weldings.info@gmail.com
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wow, tell us something we dont know…
Underwater welding has two flavors, wet and dry.
Wet welding is impractical because water
- conducts away the heat
- conducts some electricity
- contaminates the weld
- limits flux cleaning action/O2 shielding
Wet welds are poor and generally unreliable, don't work at all on anything other than low carbon steel.
Dry (hyperbaric) welds are at least possible, and reasonably reliable. Use gases under pressure to dry the weld area. Much more difficult than normal welds. Offshore welding is now typically done topside (above sea level), with the welded assemblies lowered after welding. Repairs of certain structures are really the only applications of undersea welding, where repair with a bolted on component or recovering the structure are impractical.
The gulf (Florida, Louisiana, Texas) not the other high risk one has openings for rig repair personnel. Pay is commensurate with experience. This type of work is DANGEROUS and novices usually have to serve an apprentice and will probably need to be licensed. Google "underwater welding" for more info. If you find a company that will put you to work without training or licensing run the other way. You might not survive the experience. Only work with reputable firms. You'll live longer.
Navy. You should go officer if you already have a degree. My friend was a non-distructive inspector in the Navy and got dive qualed. he makes big money as a civilian now inspecting bridges underwater.
This bloke reminds me of a guy I know. He’s been welding pipe for 51 yrs.I’m thinking of chopping and dropping a beach cruiser.I think i’ll give him a shout.
The guy is no more than a poster, he make money on his videos, like a Jack of all trades and master of none, Sorry dude! I am a retired Steamfitter, and control tech, UA, (union) I have the nuclear, oil, paper and food industries behind me, I have taught classes on , smaw, tig, mig, s/s 304-to 316ls, dissimilar metals, w/ k and J rings, pulsearc© and the bore scope process, and different type xrays you do a very poor job of explaining the processes of welding and techniques,
Relevant specifications may include BSEN ISO 729/719 and or 15618-1
great, I need someone to weld a screen door on a submarine.
expert village is by far the worse thing ever
porosity in the finished weld, which means that air bubbles get trapped inside the weld bead!It also means the metal has more carbon, or the cup size is wrong, the argon mixture or co2 is wrong, rust in the joint, or did you forget to clean the filler wire,(well it dose happen)preheat joint,( it will pull moisture out) The purpose of shielding gas is to keep the air atmosphere away from the weld pool. Without it, the weld pool reacts with the oxygen, nitrogen and hydrogen is that better
This guy is good, not typical of expert village.
Oh yes, you most certainly need to know how to weld on land, upside down, and sideways before you try underwater. It is very dangerous. College is a great place to start, I took my first welding class in college. It is a great place to start, also ask you class counselor about some good technical schools, such as ITT tech. He or She should have some great schools you could apply for. It takes a LONG time to get good enough to do underwater welding, but at least you have a goal, good luck and stick with it.
click on the add he has, thats called making money, you can do it to, it is wrong when you don’t tell the true facts, But he or what he pretends to be seams ok, cause he making money
if you get the right rating they will.
he has a canadian sounding accent
The pros are that underwater welders are highly in demand, and very well paid.
Cons are, underwater welding is very dangerous. It requires a number of advanced diving certificates, to someone with no diving experience this equals at least a year of training. Also, did I mention underwater welding is highly dangerous?
It's a lot safer to simply be an NDT technician back on dry land, this doesn't pay quite as well as an underwater welder, but this is still an in-demand jobs and a well paid one.
Here are several…
http://www.commercialdivingacademy.com/#
in Jax, Fl
http://www.diversacademy.com/
in NJ, near Atlantic City
http://www.internationaldivinginstitute.com/index.htm
in Charleston, SC