Gas Metal Arc Welding (GMAW)

Gas Metal Arc Welding (GMAW) is also known as metal inert gas (MIG) welding. In this process, the weld area is shielded by an inert atmosphere of argon, helium, carbon dioxide, or other gas mixtures. A wire-feed drive motor automatically feeds the consumable bare wire through a nozzle into the welding arc. In addition to inert shielding gases, de-oxidizers are usually present in the electrode metal to prevent oxidation.

Schematic diagram of Gas metal arc welding operation

schematic diagram of the Metal Arc Welding process equipment

The temperatures generated in Gas metal arc welding are low; the GMAW method is suitable only for thin sheets and sections less than 6 mm; otherwise, incomplete fusion may occur. GMAW operation is easy to perform and is commonly used for welding ferrous metals in delicate areas. Pulsed-arc systems are used for light ferrous and nonferrous metals. The GMAW process is used extensively in the metal fabrication industry for welding most ferrous and nonferrous metals. Because of the process's relatively simple nature, the operators' training is easy. This process is versatile, quick, and economical, and welding productivity is double that of the Submerged Arc Welding process.

Limitations of Gas Metal Arc Welding:

• The maximum size of electrodes used in Gas Metal Arc welding is less than or equal to 4mm.
• Spatter loss in this process is high.
• To keep the spatter loss within 10%, the maximum thickness of the plate can be joined by using MIG welding with single-pass welding up to 30mm thickness only.