In oxy-fuel cutting, a
torch is applied to heat metal to its kindling temperature. A stream of
oxygen is then focused on the metal, burning it into a metal oxide
that flows out of the kerf as slag.
Torches that do not blend fuel with oxygen are not
considered oxy-fuel
torches and can commonly be distinguished by a single tank. Most metals can’t
be liquefied with a single-tank torch. As a consequence, single-tank torches
are normally apt for soldering and brazing but not for
welding.
Primary Fuel in Oxyfuel Cutting
Acetylene is the main
fuel for oxy-fuel welding&cutting and is the fuel of choice for repair work and
general cutting & welding. Acetylene gas is shipped in special cylinders
designed to put the gas dissolved. The cylinders are packed with porous
materials (e.g. kapok fibre, diatomaceous earth, or
(formerly) asbestos), then occupied to around 50% capacity with acetone,
as acetylene is dissolvable in acetone. This method is required because above
207 kPa (30 lbf/in²) (absolute pressure) acetylene is unstable and
may explode.
There is about 1700 kPa (250 psi) pressure in
the tank when full. Acetylene when combined with oxygen burns at
3200 °C to 3500 °C (5800 °F to 6300 °F), highest among
commonly used gaseous fuels. As fuel acetylene's main drawbacks, in comparison
to other fuels, is high expensive.
As acetylene is changeable at a pressure roughly
equivalent to 33 feet/10 meters underwater, water immersed cutting and welding
is reserved for hydrogen rather than acetylene.
Acetylene burns at the hottest
temperature for both oxy-fuel
cutting and welding. If you want to weld infrequently with your torch arrangement,
then acetylene is the only fuel to take for your formation. It burns hot
sufficient that metals can be effectively combined together. However, acetylene
maintains to be expensive and unstable as a fuel. If you’re only cutting metal,
acetylene will preheat the metal quickly, but it’s not necessarily the only
cutting fuel option. If you want to save money, then you may want to consider
propane as a cutting fuel.
Advantages:
-
The oxy acetylene cutting
kit is very easy to apply and the process does not absorb a lot of your
precious time.
- The
machinery used here is comparatively lesser than other kinds of welding rigs
such as MIG or TIG welding ones.
- The
equipment is handier than most other types of welding rigs.
- Oxy acetylene
equipment can also be used to “flame-cut” large pieces of material.
-
In
gas welding, the source of heat and filler metal are segregated unlike arc
welding. This gives better control over filler-metal deposition rate.
Disadvantages:
- The
flame temperature is less than the temperature of the arc.
- Since
the heat generated is insufficient and hence heavy sections cannot be combined economically.
- Flux-shielding
in gas welding is not as effective as in case of TIG or MIG welding. The oxidation
cannot be neglected fully.
- More
safety problems are combined with the storage and handling of explosive gases
e.g., acetylene and oxygen.
- Gas
welding results in a larger heat affected area due to prolonged heating of
joint.
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