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MIG (Metal Inert Gas) Welding
Definition of MIG Welding
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MIG (metal inert gas) welding also known as GMAW (gas metal arc
welding) or MAG (metal active gas welding), is a semi-automatic or automatic arc welding process
in which a continuous and consumable wire electrode and a shielding gas are fed through a weld-
ing gun. A constant voltage, direct current power source is most commonly used with MIG welding.
There are four primary methods of metal transfer in MIG welding, called short circuit (also known as
dip transfer) globular transfer, spray transfer and pulsed-spray, each of which has distinct properties
and corresponding advantages and limitations. To perform MIG welding, the basic necessary equip-
ment is a welding gun, a wire feed unit, a welding power supply, an electrode wire, and a shielding
gas supply. Short circuit transfer is the most common used method whereby the wire electrode is
fed continuously down the welding torch through to and exiting the contact tip. The wire touches the
work piece and causes a short circuit the wire heats up and begins to form a molten bead, the bead
separates from the end of the wire and forms a droplet that is transferred into the weld pool. This
process is repeated about 100 times per second, making the arc appear constant to the human eye.
MIG Circuit Diagram
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6
1.
Mig Torch -
2.
Work Piece -
3.
Power Source -
4. Wire Feeder - 5. Wire Spool - 6. Gas
