3. MIG welding is a gas shielded metal arc welding
process using the heat of an electric arc between a
continuously fed, consumable electrode wire and the
material to be welded.
Metal is transferred through a protected arc column of
inert gas to the work.
4. A wire of copper coated mild steel is fed continuously from a reel
through a gun with a melting rate up to 5m/min.
Current through the wire ranges from 100 to 400 A depending upon the
diameter of the wire.
CO2 is principally used apart from argon or argon-helium
mixture as shielding gas.
The welding machine is a dc constant voltage machine.
5. Power source: MIG welding uses a dc
constant voltage transformer.
Wire feeder: A wire feeder is required to feed the
electrode wire continuously and smoothly to the
welding gun.
6. Power source: MIG welding uses a dc
constant voltage transformer.
Wire feeder: A wire feeder is required to feed the
electrode wire continuously and smoothly to the
welding gun.
Power source Wire feeder
20. Cracks: Cracking occurs when
the arc is struck but the spot is
not welded properly.
Distortion: This happens due to
uneven shrinkage of metal due
to heating.
Gas inclusion: Gas inclusions
is a wide variety of defects
that includes porosity, blow
holes, and pipes.
Welding Defects
