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Glossary

MIG Welding (GMAW)

Metal Inert Gas welding — a semi-automatic arc process using a continuously fed wire electrode and shielding gas.

Definition

What is MIG Welding (GMAW)?

Metal Inert Gas (MIG) welding, or Gas Metal Arc Welding (GMAW), is a semi-automatic arc welding process where a continuously fed consumable wire electrode is fed through a welding gun. The arc melts both the wire and the base metal, forming the weld pool. An inert or mixed shielding gas (argon, CO₂, or blends) protects the weld from oxidation. MIG welding offers high deposition rates, good bead quality, and fast production speeds — making it the dominant process for structural fabrication, heavy assemblies, and production welding. ATS Metal Fabrication uses MIG welding for structural steel frames, enclosures, chassis, and high-volume assemblies.

Types & Variants

  • • Short-circuit GMAW (thin gauge)
  • • Spray transfer GMAW (thicker sections)
  • • Pulsed GMAW (spatter reduction)
  • • Dual-shield / FCAW-G (flux-cored with gas)

Common Applications

  • • Structural steel frames and beams
  • • Sheet metal enclosures and chassis
  • • Brackets and mounting hardware
  • • Heavy weldments and machine bases

FAQ

Frequently Asked Questions

What is the difference between MIG and TIG welding?
MIG welding uses a continuously fed wire electrode for high-speed, high-deposition production welding. TIG uses a non-consumable tungsten electrode and a manual filler rod for precision, clean welds on thin or high-alloy materials. MIG is faster; TIG is cleaner and more precise.
What materials can be MIG welded?
MIG welding works on mild steel, stainless steel, and aluminum. The shielding gas and wire composition are adjusted based on material type. Mild steel is typically welded with C25 (75% argon / 25% CO₂) mix; aluminum requires pure argon; stainless requires a tri-mix gas.
Is MIG welding strong enough for structural work?
Yes. MIG welding (GMAW) produces full-penetration welds that meet structural codes such as CSA W59 and AWS D1.1. ATS Metal Fabrication's CWB W47.1 certification covers structural MIG welding. The strength of a MIG weld meets or exceeds the base metal strength when proper procedures are followed.

Related Terms

See Also

TIG Welding (GTAW) Metal Fabrication Structural Steel Fabrication CWB Certification

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