MIG welding (GMAW – Gas Metal Arc Welding) joins metals using a continuously fed consumable wire electrode and shielding gas to protect the molten weld pool from atmospheric contamination. This versatile, productive process is fundamental to modern fabrication operations.

MIG process advantages include high deposition rates improving productivity, continuous wire feed eliminating frequent stops, relatively easy operator training and skill development, all-position capability, and minimal post-weld cleanup due to low slag production. These characteristics make MIG ideal for production fabrication where efficiency matters.

Process variations extend MIG capabilities: short-circuit transfer for thin materials and out-of-position welding, spray transfer for high deposition on thick sections, pulse transfer balancing penetration and heat input, and flux-cored wire options for field welding or materials requiring deoxidizers.

For pressure vessel fabrication, MIG typically fills and caps groove welds after TIG root passes, providing productivity while maintaining quality. Material compatibility spans carbon steel, stainless steel, and aluminum. Shielding gases—argon/CO₂ mixtures, pure argon, argon/helium—are selected based on material and transfer mode.