Page 170 - CITS - Fitter Trade Pactical - Volume - 2

FITTER - CITS

Demonstration on Importance of arc welding in Industry

& uses

Objectives: At the end of this exercise you shall be able to
• explain about the importance of Arc Welding in Industry.
• illustrate different uses of Arc Welding.

Arc welding is a welding process that is used to join metal to metal by using electricity to create enough heat to
melt metal, and the melted metals, when cool, result in a binding of the metals.
Arc welding can deliver extremely strong bonds even between thin metals. The construction industry uses arc
welding to guarantee strong, sustainable connections within buildings, bridges, and other infrastructures. Other
industries that use arc welding are the oil and gas industry and the power industry.
Advantages
• Cost – equipment for arc welding is well-priced and affordable, and the process often requires less equipment
in the first place because of the lack of gas.
• Portability – these materials are very easy to transport.
• Works on dirty metal.
Disadvantages

There are a few reasons why some people look to other options beyond arc welding for certain kinds of projects.
These downsides can include:
• Lower efficiency – more waste is generally produced during arc welding than many other types, which can
increase project costs in some cases
• High skill level – operators of arc welding projects need a high level of skill and training, and not all professionals
have this

• Thin materials – it can be tough to use arc welding on certain thin metals
Job Sequence

TASK 1 : Striking and maintaining arc

• Check the size of the raw material.
• Mark and file to size.
• Clean the metal surface with a steel wire brush and wipe off the oil and grease if any.
Dirt or rust makes poor connections.
• Wear safety apparel (Protective clothing)

• Connect the welding cables with the machine and the job.
Check the cables for damage and loose connections. Check whether the earth-clamp is properly
attached.

• Fix a Ø 4mm M.S. electrode in the holder.
Ensure the electrode is firmly held in the holder from the bare end.
• Set the welding current (amperage) 140-150 amps.
If the welding machine is a D.C. one, connect the electrode to the negative.
• Start the welding machine.

• Strike and maintain the arc by the scratching method.
Use a welding screen fitted with proper coloured glasses while arc-welding.

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CITS : C G & M - Fitter - Exercise 49