Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Under water welding


Published on

About Under water Welding In and Out fully has been Discussed in the PPT by the Students

Published in: Engineering
  • Login to see the comments

Under water welding

  3. 3. NEED FOR UNDERWATER WELDING  To repair the cracks in ships ,bridge and submarine.  For quick process in under water welding.  To construction of pipe line in under sea.  To weld any cracks in oil pipe line.
  4. 4. Requirement of underwater welding Power supply requirements 400 Amp or larger. DC generators, motor generators and rectifiers are acceptable power supplies.  Power converters.  Welding Generator, Pre-Setup.  Diesel Driven Welding Generator Amperage and Voltage settings.  Gas Manifolds.
  5. 5.  Underwater Oxygen-Arc Welding Torches. 1.Collet or grip 2.Oxygen valve 3.Flash arrester  Waterproofing Surface Electrodes. 1.Epoxy 152 2.Lee lac 30-l2093 3.Polyurethane
  6. 6. Difference between normal welding and underwater welding Under water welding 1 . Underwater Welding & Burning: 6,500 – 10,000° F Under the Sea. 2. Under the water, metal sounds different. It’s high pitched but muffled like a siren entering a tunnel. It dissipates quickly out into the waves .  Ground welding 1. In the electric arc, the temperature is very high of the order of 6,000-8,000 °C for the GTAW, GMAW, FCAW and SAW processes. 2. It up to 10,000 20,000 °C for the PAW process and well above the boiling point of the base and filler materials
  7. 7. Sea driver equipment Fully insulated electrode holder. Oxygen cylinder. HOFR cable for power supply (double insulated cable). Dry suit, helmet and head light. Electrode core wire with heavy coating.
  8. 8. Classification of under water welding Wet welding:  In this process it is directly exposed to the environment.  And special water proof electrode is used in this type of welding. Dry welding:  In this process it is seal by closed chamber filled with gas to elevated pressure.  Gas tungsten arc welding is most commonly used.
  9. 9. Wet welding It is carried out directly at ambient water pressure with the welder/driver in water By using water proof stick electrode and without any physical barrier between water and welding Mostly used Gas metal arc welding.
  10. 10. Wet welding process
  11. 11. Advantage of wet welding Minimal amount of equipment is needed. Operating speed is high. No seal chamber is required.
  12. 12. Disadvantage of wet welding Repaid quenching of the weld metal by surrounding water. Decreases impact strength and losses. Hydrogen embattlement causes cracks. Poor visibility in water. Electric shock will occurred.
  13. 13. Application of wet welding It is key technology for repairing marine structure . Welding is directly performed under water is directly exposed to the wet environment. Increased freedom movement makes more effective , efficient and economical. Supply is connected to the welder / driver via cables or hoses.
  14. 14. Dry welding Hyperbaric welding is the process in which a chamber is sealed around the structure to be welded and is filled with a gas ( He and 0.5 bar of Oxygen) at the prevailing pressure.
  15. 15. Hyperbaric welding process
  16. 16. Advantages of Dry welding More safety then wet welding. Good Quality weld. Surface monitoring. Non destructive testing possible.
  17. 17. Disadvantages of Dry welding Higher cost of process, training, etc. Large quantity of costly and complex equipment. More deep, more energy requirement. It should be weld only reachable place.
  18. 18. Application of underwater dry welding To Maintain the oil pipe lines in under water. Construction of pipe line under sea.
  19. 19. Advance in under water welding LASER BEAM WELDING
  20. 20. Risk involved in under water welding Electric shock explosion. Risk is to the life of the welder. High pressure is formed. Shark attack under deep sea welding.
  21. 21. Dangerous and difficulties Hydrogen and oxygen are dissociated from the water and will travel separately as bubbles Oxygen cutting is about 60 percent efficient Above river beds, especially in mud, because trapped methane gas in the proper concentrations can explode. There is a risk to the welder/diver of electric shock. There is a risk that defects may remain undetected The other main area of risk is to the life or health of the welder/diver from nitrogen introduced into the blood steam during exposure to air at increased pressure
  22. 22. Future scope and developments Present trend is towards automation. THOR – 1 (TIG Hyperbaric Orbital Robot) is developed where diver performs pipefitting, installs the track and orbital head on the pipe and the rest process is automated.