4. DEFINATION
Underwater welding is the process
of welding at elevated pressures,
normally underwater. Underwater
welding can either take place wet in
the water itself or dry inside a
specially constructed positive
pressure enclosure and hence a dry
environment.
5. WORKING PRINCIPLE
The process of underwater wet wel
ding takes in the following manner:
The work to be welded is connected
to one side of an electric circuit, and
a metal electrode to the other side.
... At the same time, the top of
electrode melts, and metal droplets
are projected into the weld pool.
8. WET WELDIND
Wet welding Wet underwater
welding directly exposes the diver
and electrode to the water and
surrounding elements. Divers
usually use around 300–400 amps
of direct current to power their
electrode, and they weld using
varied forms of arc welding. ... They
will overheat if used out of the water
9. Dry welding
In dry underwater welding the
spot to be welded is covered by
a chamber from which water is
excluded under pressure.
The welding so done is similar
to that carried out in open air
conditions except that the fumes
and gases generated in
10. ELECTRODE USING DETAILS
Hydroweld FS™ Are the industry
standard wet welding electrodes where
high quality underwater welding is
required. These
unique electrodes specifically designed
to produce high quality welds
underwater, in freshwater or
brine/seawater, in all positions and on a
range of carbon steels and depths of
11. UNDERWATER WELDING
ADVANTAGE DISADVANTAGE
The advantages of
underwater welding
are of economical
nature, because
underwater-welding
for
marine maintenance a
nd repair jobs
bypasses the need to
pull the structure out
of the sea and saves
valuable time and dry
docking costs.
Rapid quenching
decreases impact
strength and ductility.
Hydrogen
embrittlement. Poor
visibility in water.
Higher energy density
of hydrogen, higher
efficiency.
12. APPLICATIONS
Applications of underwater
welding include underwater pipeline
s, offshore oil drilling rigs, docking
facilities, mining, ships, barges,
dams, locks, sub-sea habitats and
nuclear power facilities.
Some underwater welders are self-
employed.
