MIG welding is a gas shielded metal arc welding process that uses an electric arc between a continuously fed consumable electrode wire and the material being welded to transfer metal. A wire feeder continuously feeds a copper-coated mild steel wire through a welding gun at a rate up to 5 meters per minute while a DC constant voltage power source supplies a current between 100 to 400 amps depending on the wire diameter. Carbon dioxide or argon-helium mixtures are used as shielding gases to protect the weld area.

2. What is MIG WELDING

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

7. Welding gun Conduit and hoses

8. Welding gun Conduit and hoses

19. Disadvantages

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