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Welding Processes Overview (SMAW, GMAW, FCAW, GTAW, SAW)

The five arc welding processes a welding supply counter sees most are SMAW, GMAW, FCAW, GTAW and SAW. This sheet explains what each is, where it is used and which consumables it pulls.

Ref WG-0101AWS A3.0

Draft, open for review. Check every value against the governing standard and the manufacturer’s data before use.

What it is

Arc welding melts metal with an electric arc between an electrode and the work. The processes differ in how the electrode is fed and how the molten weld is shielded from air. AWS A3.0 sets the standard terms and abbreviations. SMAW (shielded metal arc welding, stick) uses a flux-coated rod. GMAW (gas metal arc welding, MIG) feeds a solid or metal-cored wire with shielding gas. FCAW (flux-cored arc welding) feeds a tubular wire filled with flux, with or without gas. GTAW (gas tungsten arc welding, TIG) uses a non-consumable tungsten electrode, a separate filler rod and inert gas. SAW (submerged arc welding) feeds wire under a blanket of granular flux.

How to identify

Ask how the customer welds or look at the equipment. A stinger holding a rod is SMAW. A wire feeder and gun with a gas bottle is GMAW or gas-shielded FCAW. A wire feeder with no gas is self-shielded FCAW. A torch with a tungsten and a separate hand-fed rod is TIG. A tractor or fixed head dropping granular flux over the joint is SAW.

Process comparison

Process	Common names	Shielding	Typical uses	Consumables it pulls
SMAW	Stick	Flux coating on electrode	Field repair, structural, pipe, outdoor work	Electrodes (AWS A5.1, A5.5), electrode holders, ground clamps, rod ovens for low-hydrogen rods
GMAW	MIG	External gas	Fabrication, sheet metal, production	Solid or metal-cored wire (AWS A5.18, A5.28), shielding gas, contact tips, nozzles, liners
FCAW-G	Dual shield, gas-shielded flux core	Flux plus external gas	Structural steel, heavy fabrication, shipbuilding	Flux-cored wire (AWS A5.20, A5.36), gas, tips, nozzles
FCAW-S	Self-shielded flux core, inner shield	Flux only	Outdoor and field work, structural erection	Self-shielded wire, drive rolls for cored wire, tips
GTAW	TIG	Inert gas, usually argon	Thin material, stainless, aluminum, pipe roots, precision work	Tungsten electrodes, filler rods, cups, collets, gas lenses, argon
SAW	Sub arc	Granular flux	Thick plate, long seams, pipe mills, tanks	Solid or cored wire and flux (AWS A5.17, A5.23), contact tips

Key points

Each process needs a matching power source output. Stick and TIG use constant current. MIG and flux core use constant voltage in most setups.
Wind blows away shielding gas. Outdoors, stick and self-shielded flux core are usually the practical choices.
Filler metal must be classified for the process. A TIG rod is not a MIG wire, even if the chemistry is similar.
Codes such as AWS D1.1 and the job's welding procedure specification (WPS) set the process, filler and settings for code work.
Fume, light and fire hazards apply to every process. See the safety sheets for PPE and ventilation.

Common mistakes

Selling flux-cored wire to a MIG customer who has no knurled drive rolls for it.
Selling gas-shielded flux-cored wire for a welder that has no gas setup.
Assuming a stick welder can run TIG without the right torch, gas and controls.
Overlooking the gas: GMAW, FCAW-G and GTAW all need the correct shielding gas.

Governing standards: AWS A3.0 (standard welding terms and definitions); AWS A5 filler metal specifications; AWS D1.1 for structural steel work.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.

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