Let the Weld Guru guide you through the world of Underwater Welding and Cutting
The two main categories of underwater welding techniques are wet underwater welding and dry underwater welding, or hyperbaric welding.
In wet underwater welding, shielded metal arc welding is commonly used, employing a waterproof electrode. Other processes that are used include flux cored arc welding and friction welding.
In each of these cases, the welding power supply is connected to the welding equipment through cables and hoses. The process is generally limited to low carbon equivalent steels, especially at greater depths, because of hydrogen-caused cracking. In dry underwater welding the weld is performed at the prevailing pressure in a chamber filled with a gas mixture sealed around the structure being welded.
For this process, gas tungsten arc welding is often used, and the resulting welds are generally of high integrity. The applications of underwater welding are diverse – it is often used to repair and construct ships, offshore platforms, and pipelines.
Steel is the most common material welded.
For deep water welds and other applications where high strength is necessary, dry water welding is most commonly used.
Research into using dry water welding at depths of up to 1000 m are ongoing.
In general, assuring the integrity of underwater welds can be difficult, especially wet underwater welds, because defects are difficult to detect. For the structures being welded by wet underwater welding, inspection following welding may be more difficult than for welds deposited in air.
Assuring the integrity of such underwater welds may be more difficult, and there is a risk that defects may remain undetected. The risks of underwater welding include the risk of electric shock to the welder.
To prevent this, the welding equipment ought to be properly insulated, and the voltage of the welding equipment should be controlled.
Underwater welders must also consider the safety issues that normal divers face; most notably, the risk of decompression sickness due to the increased pressure of inhaled breathing gases.
Another risk, generally limited to wet underwater welding, is buildup of hydrogen and oxygen pockets in the weld, because these are potentially explosive. From Wikipedia, the free encyclopedia.
Work below surface of water, using scuba gear to inspect, repair, remove, or install equipment and structures. May use a variety of power and hand tools, such as drills, sledgehammers, torches, and welding equipment. May conduct tests or experiments, rig explosives, or photograph structures or marine life. Excludes fishers and related fishing workers, athletes and sports competitors, and police and sheriff's patrol officers. 2004 employment: 2,900 Projected 2004-14 employment change: About as fast as average Most significant source of postsecondary education or training: Moderate-term on-the-job training Specific Job Description Carry out non-destructive testing such as tests for cracks on the legs of oil rigs at sea. Check and maintain diving equipment such as helmets, masks, air tanks, harnesses and gauges. Communicate with workers on the surface while underwater, using signal lines or telephones. Cultivate and harvest marine species, and perform routine work on fish farms. Cut and weld steel, using underwater welding equipment, jigs, and supports. Descend into water with the aid of diver helpers, using scuba gear or diving suits. Drill holes in rock, and rig explosives for underwater demolitions. Inspect and test docks, ships, bouyage systems, plant intakes and outflows, and underwater pipelines, cables, and sewers, using closed circuit television, still photography, and testing equipment. Install pilings or footings for piers and bridges. Install, inspect, clean, and repair piping and valves. Obtain information about diving tasks and environmental conditions. Operate underwater video, sonar, recording, and related equipment to investigate underwater structures or marine life. Perform activities related to underwater search and rescue, salvage, recovery, and cleanup operations. Perform offshore oil and gas exploration and extraction duties such as conducting underwater surveys and repairing and maintaining drilling rigs and platforms. Recover objects by placing rigging around sunken objects, hooking rigging to crane lines, and operating winches, derricks, or cranes to raise objects. Remove obstructions from strainers and marine railway or launching ways, using pneumatic and power hand tools. Remove rubbish and pollution from the sea. Repair ships, bridge foundations, and other structures below the water line, using caulk, bolts, and hand tools. Salvage wrecked ships and/or their cargo, using pneumatic power velocity and hydraulic tools, and explosive charges when necessary. Set or guide placement of pilings and sandbags to provide support for structures such as docks, bridges, cofferdams, and platforms. Set up dive sites for recreational instruction. Supervise and train other divers, including hobby divers. Take appropriate safety precautions, such as monitoring dive lengths and depths, and registering with authorities before diving expeditions begin. Take test samples and photographs to assess the condition of vessels and structures. Detailed Work Activities adhere to safety procedures assemble, dismantle, or reassemble equipment or machinery build or repair structures in construction, repair, or manufacturing setting burn (cut), trim, or scarf metal objects charge blasting holes with explosives cut metal or plastic determine amount or kind of explosive needed to complete job erect machinery in marine or maritime setting estimate time or cost for installation, repair, or construction projects fabricate, assemble, or disassemble manufactured products by hand identify base metals for welding identify properties of metals for repair or fabrication activities inspect machinery or equipment to determine adjustments or repairs needed maintain or repair boat or ship hull or superstructure maintain repair records maintain welding machines or equipment move or fit heavy objects operate cameras operate video recorders perform safety inspections in industrial, manufacturing or repair setting position, align, or level machines, equipment, or structures read blueprints read specifications read work order, instructions, formulas, or processing charts repair or replace gas, steam, sewer, or water piping or fixtures select ship repair method set up specialized rigging signal directions or warnings to coworkers stretch, bend, straighten, shape, pound, or press metal or plastic understand construction specifications use acetylene welding/cutting torch use arc welding equipment use combination welding procedures use hand or power tools use two-way radio or mobile phone weld together metal parts, components, or structures
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