MIG/MAG or GMAW
With MIG (Metal Inert Gas) or MAG (Metal Active Gas) welding also called Gas-shielded Metal Arc Welding (GMAW) an arc is maintained between a continuous solid wire electrode and the work piece.
The arc and weld pool are shielded by a stream of inert or active gas. The process is suitable for most materials and filler wires are available for a wide range of metals.
Flux Cored Arc Welding
Flux Cored Arc Welding is quite similar to MIG/MAG welding as far as operation and equipment are concerned. However, the electrode is not solid but consists of a metal sheath surrounding a flux core.
As in MIG/MAG welding, the flux cored process depends on a gas shield to protect the weld zone from atmospheric contamination. The gas is either applied separately or it is generated from the decomposition of gas forming ingredients contained in the flux core.
Stick/MMAW or SMAW
Welding with stick electrodes is called Manual Metal Arc Welding (MMAW) welding or Shielded Metal Arc Welding (SMAW). It is the oldest and most versatile of the various arc welding processes.
An electric arc is maintained between the end of a coated metal electrode and the work piece. The molten slag floats to the top of the weld puddle where it protects the weld metal from the atmosphere during solidification.
Plasma Arc Welding
Plasma Arc Welding is a process, which is very similar to TIG welding. It is a development of the TIG method, which is designed to increase productivity. In Plasma Arc Welding, there are two separate gas flows, the plasma gas which flows round the tungsten electrode and subsequently forms the core of the plasma arc and the shielding gas which provides protection for the molten pool.
This process uses a concentrated electrical arc which melts the material through a high-temperature plasma beam.
TIG or GTAW
TIG (Tungsten Inert Gas) welding or Gas-Shielded Tungsten Arc Welding (GTAW) is a process, which uses a non-consumable solid tungsten electrode.
The electrode, the arc and the area surrounding the molten weld puddle are protected from the atmosphere by an inert gas shield.
If a filler metal is necessary, it is added to the leading edge of the molten puddle.