With this mind, we want to explore the questions: how does underwater welding work? How do welder-divers perform welding tasking at elevated pressures, and in particular underwater? Wet welding is a process that produces an electric arc between an electrode and the infrastructure being welded together. Before carrying out this weld, the underwater welders check the surroundings for any obstructions or safety hazards.
It is also crucial that they keep electrodes clean. To prevent underwater welders from being electrocuted a thick layer of gaseous bubbles are created externally around the electrode, covering the weld and shielding the electricity from water, corrosive gasses and other oxidising compounds. Since the welder can use both hands to hold the welding gun, this process is simple to master.
Even new users can start making high quality welds straight away. This welding method is somewhat similar to TIG welding process.
Plasma arc welding creates an electric arc between the workpiece and electrode that is usually made from sintered tungsten. The electrode is located within the torch body. Plasma arc can then be kept separately from inert gas. Plasma is injected through the copper nozzle at high speeds. The fine-bore nozzle restricts the plasma along one direction for accurate results.
The temperature can go up 50, 0 F and even more. For extensive underwater welding deep below the water level, underwater welders must work in pairs within the hyperbaric chamber. First, the hyperbaric chamber is lowered to the right depth and filled with breathable gases.
Using a diving bell, the diver goes down to the same level, enters the chamber and starts welding. Shifts can last between six and eight hours.
Underwater welders face much greater dangers compared to land-based welders since there are many variables that can complicate matters. Different factors must be considered for safety purposes, such as gas pressure, water pressure, diving equipment, specialized welding equipment, restricted space, power supply and more.
Underwater welders work in remote and dangerous locations, such as offshore oil rigs and pipelines. Although this work is financially rewarding, it is also one of the most dangerous jobs.
The fatality rate for underwater welding is one of the highest even among the most dangerous occupations. If proper care is not taken, a small mistake can easily lead to death or long-term health complications. Project managers and engineers should coordinate with underwater welders to address safety concerns. The following are the greatest dangers faced by diver-welders.
But keep in mind that land-based welders also face the risk of an explosion if they are working in a poorly ventilated space. To prevent the build-up of combustible gases, the welding space should be well ventilated for both surface and underwater welders.
As you can expect, underwater welding equipment will be slightly different as compared to land-based welding equipment. Wet welding requires double insulation for wires. Alternating current is never used in wet welding. Only direct current is utilized. Additional menu. What is Underwater Welding? Risks Most people know that salt water is a good conductor of electricity. Rewards That Match Risks Due to the challenging nature of the job and risks involved, underwater welding is a highly paid occupation.
Types of Underwater Welding There are two basic categories of underwater welding: Dry Welding People normally visualize underwater welding as a job that is performed with the diver fully submerged. Wet Welding Wet welding can be performed based on a number of factors. How Is Underwater Welding Done? Here are the different welding processes that can be used. Wet Welding Shielded metal arc welding, which is also known as stick welding, is a popular choice for wet welding.
Flux-Cored Arc Welding This versatile welding method can be used for cast iron, nickel alloys and other kinds of metal alloys.
Friction Welding This technique employs heat and friction rather than melting the filler material to fuse metal. Dry Welding As mentioned above, a hyperbaric chamber is used in dry welding for more reliable results. Habitat Welding In this method, underwater welders operate in a small chamber, which is called a positive pressure enclosure or a habitat. Dry Spot Welding Dry spot welding technique is utilized for small chambers.
Dry Chamber Welding Dry chamber uses a small-sized chamber to accommodate only the upper body of the welder. Underwater Welding Dangers Underwater welders face much greater dangers compared to land-based welders since there are many variables that can complicate matters. If the scuba gear fails in any way, the diver can drown if he or she is too deep below the water surface.
Combustible mixtures can be created from flammable gases like oxygen and hydrogen. If these pockets grow too large and are ignited, the resultant explosion can be lethal. This poses a serious risk to diver-welders. Electric shock. Electrocution remains a serious threat due to the large currents involved in welding. All equipment used for underwater welding must be waterproof.
Keep the equipment well maintained. Make it a habit to always test the equipment prior to use. Make sure that there are no leaks in any equipment.
Equipment should also be properly insulated. A knife switch is also present to turn off the power to the welding stinger.
Lung, ear and nose damage. You should be careful of spending too much time deep underwater. This can lead to long-term health issues related to the nose, lungs and ears. Decompression Sickness. This occurs due to the inhalation of gases at different pressures. Decompression sickness can prove to be fatal in extreme cases. It will surprise many people to learn that the risk of electrocution does not head the list of dangers for underwater welders.
As we touched on above, all of the machinery used is waterproofed, a knife switch ensures power is only used when required and all divers wear protective clothing.
It is also worth noting that the welding arc creates a path of least resistance between the electrode and the working area thereby reducing the chances of being electrocuted. So what are the main dangers? The main dangers of welding underwater include decompression sickness, hypothermia, drowning, and explosions and, perhaps most important of all, Delta P. Delta P is a process by which two sides of connected water will automatically rebalance when any blockages are removed.
When you bear in mind some of the depths at which deep sea welding can occur, these pressures can be enormous. When welding underwater there will usually be a team in constant communication with the underwater welders. They will be ready to enter the water to assist when required. As you would expect, in such a potentially dangerous field of work, employers will pay the highest rates for those underwater welders with the most experience.
Predicting the life expectancy of an underwater welder is not a precise science. There have been a number of studies over the years looking at this subject.
However, it might surprise many to learn that a study by the US Defence Technical Information Center cast a very interesting light on life expectancy. While many are overly concern about the threat of electrocution when using welding equipment underwater, there is only one officially reported death from electrocution which occurred back in The individual involved was alleged to have carried out underwater welding in 10 feet of water wearing protective clothing except he was barefoot.
An article by the US Center for Disease Control and Prevention provided statistics from which it was possible to calculate the underwater welding death rate. It found that the rate of death was more than 40 times the American national average — 11 underwater welders dying each year. A further study between and , although not carried out on a scientific basis, used data from the Divers Association in America.
The figures indicated welder divers were dying between the age of 35 and With many only entering diving school at 20 years of age, the average working life expectancy was between 10 and 15 years.
While it is difficult to challenge or confirm these figures, this is the only life expectancy survey carried out into the deep sea welding industry. Underwater welding is one of the most specialised jobs in the world. It is also one of the most dangerous for reasons which are not immediately obvious. Many people automatically assume that electrocution is the main danger. In reality it is possible to minimise the risk of electrocution to near zero if all safety precautions are respected.
The main dangers come from different aspects of diving from decompression sickness to explosions, from Delta P to drowning.
A non-scientific study into the life expectancy of underwater welders was alarming to say the least. It suggested a death rate of more than 40 times the US average. Specialist projects will require experienced underwater welders who do not come cheaply. For those looking at a career in underwater welding the best advice would be to perfect your diving skills.
While also appreciating all of the safety precautions surrounding the use of welding equipment underwater. Some of the more experienced specialist underwater welders can earn six-figure salaries. However, for this type of income there will be a significant increase in the risk factor. You must be logged in to post a comment. Facebook-f Linkedin Twitter. Underwater Welding Read this and be an expert in 5 minutes!
October 10, Jon Anderton. There are two types of underwater welding known as dry welding and wet welding Dry welding takes place in extreme pressurised areas, such as under water, with the welders working from a pressurised chamber known as a habitat Wet welding takes place in the water using waterproofed equipment to minimise the danger of electrocution Electrocution is not the main danger to underwater welders, with more lives lost through diving incidents such as drowning, Delta P and underwater explosions Death rates 40 times the US national average highlight the dangers of deep sea welding.
How does underwater welding work?
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