MIG Welding Information | CNC Directory

MIG Welding (metal inert gas welding), sometimes referred to as GMAW (gas metal arc welding) is a welding process in which surfaces are bonded with a filler metal in the presence of an inert gas. MIG is the most common welding process found today, as it is versatile, fast and can be automated easily. The car manufacturing industry, in fact, uses almost exclusively MIG welding for its metalwork.

MIG welding began to develop in the early 19th century, when Sir Humphrey Davy invented the electric arc and, along with Russian scientist Vasily Petrov began to realise its potential use in welding. The technology advanced slowly until the mid first half of the 20th century, when P Nobel invented the first apparatus to resemble modern MIG welding equipment in 1920. This, however, did not use a shielding gas, as this technology did not appear till later.

Only in 1948 was true MIG welding invented: however, the high expense of inert gas at this time hugely limited its use to non-ferrous substances, and no substantial cost-effectiveness was gained. It was with the first use of Carbon Dioxide as an inert gas in 1953 that MIG welding really took off as it made welding all metals, especially steel more economical. The technology has done nothing but improved since that date, with MIG now being the most used welding process in the world. It is, however, not used for underwater welding, due to its need for an inert gas, however, is ideal in space environments, as there is no oxygen to react with the welding metal.

The typical modern MIG welding apparatus has five main parts: the welding gun; the power supply; the wire feeding unit; the electrode source and the canister of shielding gas. The welding gun is the hand held part of the welding device which strikes the electric arc; the wire is then fed through the centre of the nozzle to fill the weld whilst the inert gas is “sprayed” out around the welding area.

The actual electrodes used in MIG welding vary greatly depending on the application, but almost have in small parts deoxidising metals, such as aluminium, manganese and titanium. The shielding gas, which serves to protect the molten (therefore more reactive) metal from reacting with gases in the air such as oxygen, is an inert gas, such as argon, helium and krypton, although these can only be used for non ferrous welding. Carbon Dioxide, however, is often used by welders as it enables the welder to work on steel and iron.