What is MIG Welding?

Metal Inert Gas (MIG) Welding

More technically known as Gas Metal Arc Welding (GMAW), the MIG method is a process which utilizes a continuous solid wire electrode, heated and fed through a welding gun into the weld pool. The welding gun then feeds a shielding gas simultaneously with the wire electrode to help protect the weld pool from atmospheric contaminants.

Who uses MIG Welding?

MIG welding is used nearly everywhere in the welding industry. Beyond that, it is also many hobbyist's preferred choice. Applications are seen throughout the heavy to medium-heavy industry, such as shipbuilding, manufacturing structural steels, pipelines, pressurized containers, sheet metal industry, car industry and small industries. It is also excellent for repair and maintenance businesses. Due to its semi-automatic and automatic operation, the MIG process shines in high production welding applications.

The Technique

The welding gun is the welder's main tool. Through it the filler wire and shielding gas runs. Weld position, angle, stick-out length and welding speed are important parameters for MIG welding. The arc is ignited with a trigger in the gun, and the gun is then moved at a steady welding speed along the weld groove. The formation of the molten weld must be observed. The position and distance of the welding gun relative to the workpiece must be maintained constant. It is particularly important that the welder concentrates on managing the molten weld at all times.

Advantages

  • High quality welds can be produced much faster when compared to MMA or TIG welding.
  • Less post-weld cleaning, since there is no slag.
  • The shielding gas protects the arc, so that little alloying elements are loss during metal transfer, which results in less weld spatters.
  • Able to use on a wide variety of metals and alloys, including aluminum, copper, magnesium, nickel, iron, and many of their alloys.
  • Able to adapt its configuration to better suit certain operations or techniques. Including semi and fully automatic modes, constant power or constant voltage mode, droplet, dip or pulsed metal transfer modes, as well as a range of different shielding gasses to employ.

Disadvantages

  • Cannot be used in certain positions, such as the overhead or vertical positions. This is due to the high input and fluidity of the weld puddle.
  • Higher initial and maintenance cost, from shielding gas, replacement tips and nozzles.
  • Certain weld setting requires high skill level.
  • Limited portability, especially with gas cylinders.
  • Requires a direct and constant current source, and constant flow of gas.