1. UNDERWATER WELDING

2.  INTRODUCTION  CLASSIFICATIONS  PRINCIPLE  ADVANTAGES  DISADVANTAGES  CONCLUSION

3.  It is an important tool for underwater fabrication works.  Any repair method will require the use of under water welding.  Such as number of offshore structures including oil drilling rigs, pipe lines.

4. CLASSIFICATIONS  WET WELDING( Manual metal arc welding )  DRY WELDING( Hyper baric welding)

5.  It is directly expose to the wet environment.  It is open air welding.  Most effective efficient economical method.

6.  This method produce high quality welded joints.  Gas tungsten arc welding use this process.  The area under the floor of the habitat is open to water.  The welding is done in the dry but at the hydrostatic pressure of the sea water surrounding the habitat.

7. WET WELDING  Speed of the operation is very high.  Equipments are very minimum.  The expenditure is very minimum.

8. DRY WELDING  Good quality  Good surface finish  It will not affected by ocean currents and marine animals  Welder safety  I

9. WET WELDING  Poor visibility  Weld is quenched is very fast in under water.  It decreases impact strength and ductility  Hydrogen Embrittlement  Amount of voltage very limited

10. DRY WELDING

11.  Large quantities of complex equipment  Cost is very high  High voltage are required

12.  Sufficient literature is not available  It as led to the development of alternative welding methods like friction welding,explosive welding.