Common Abbreviations and Welding Symbols

[Rancher Ed]

Here are some of the standard abbreviations for different welding processes, what they stand for, and common equivalent terms.

• SMAW = Shielded Metal Arc Welding = 'Stick' welding (also called MMA for manual metal arc in Europe I believe)
• GMAW = Gas Metal Arc Welding = 'MIG' (Metal Inert Gas) and 'MAG' (Metal Active Gas) = slang term 'wire-feed welding'
• GTAW = Gas Tungsten Arc Welding = 'TIG' (Tungsten Inert Gas) = older slang term 'Heliarc welding'
• OFW = Oxygen Fuel Welding - includes oxy-acetalyne as well as other fuel gasses = sometimes called 'Gas Welding'

These first four are the ones most likely to be seen and used outside of specialized welding facilities.

• SAW = Submerged Arc Welding, often shorted to sub-arc.
• PAW = Plasma Arc Welding - Similar to GTAW but higher energy density with the plasma
• LBW = Laser Beam Welding
• EBW = Electron Beam Welding, often called e-beam
• Hotwire-GTAW = mechanized GTAW where a second power source is connected to the filler wire; used to produce high quality overlays for corrosion resistance, etc.
• PTA = Plasma Transferred Arc; similar to PAW but the plasma is used to melt an overlay powder to the part instead of penetrating a joint.

If you ever try to read drawings or fabrication plans for something that has welding symbols on it, AWS standard A2.4 will be extremely helpful. If you search online you can typically find a free download of an older revision. Here is a link to just the reference chart: American Welding Society Welding Symbol Chart

A lot of this information is not needed for projects around the house, but knowing the different terms can be helpful when trying to look something up or following someone else's project. Any important abreviations I missed or clarification that should be added to the above?

 

[MC]

Thanks Ed. I'm going to make this post sticky. Keep the great posts coming!

 

[Rancher Ed]

Thanks Muhammad. Hopefully it will be helpful to some of the members new to welding.

One common and important abbreviation I forgot is FCAW which should make the first four the first five. Anyway:

• FCAW = Flux Core Arc Welding = very similar to GMAW, also a 'wire-feed' process, sometime loosely included when the term 'MIG' is used

Additional Details:
GMAW and FCAW are both constant voltage (CV) processes and use the same power supply. CV means the user sets the voltage they want to use, and the machine adjusts the amps/wire feed speed to produce that voltage (even as the welding torch gets closer or farther from the work piece). This is in contrast to constant current (CC) power supplies which is what SMAW and GTAW use. In a CC machine the user sets the current and the voltage is dependant on the arc length (how close or far away the electrode is). As the names imply, FCAW has some type of flux which results in some type of slag on the completed weld which then must be removed.

GMAW Cored vs Solid Wire:
All solid wire is GMAW and requires wire-feed rollers for solid wire. Cored wire can be either GMAW or FCAW depending on what is inside, and requires different rollers from solid wire to avoid crushing the wire. If the cored wire contains powdered metal, the process is still GMAW. For most hobbyists metal cored wire has no real benefits. In industry the two main advantages are: 1) alloying elements which cannot be included in the actual wire can be placed in the powdered core to increase the weld metal strength and/or match the base metal chemistry, and 2) with the correct parameters the cored wire can achieve a higher deposition rate.

FCAW Gas vs Self Shield:
All FCAW wire is cored and has some type of flux inside it. For self-shielded wire, the flux is very similar to the coating on stick electrodes. When the wire melts, part of the flux forms an inert gas which supports the arc and protects the molten weld puddle. The other part of the flux forms a protective slag on the weld which must be chipped off once it cools, just like SMAW. In gas-shield FCAW, the flux de-oxidizes the weld and can also help remove base metal contaminates. This is why SMAW and FCAW are more forgiving of welding on dirty base material compared to GMAW - they both have a flux to capture the dirt and float it out in the slag which gets removed.

 

[Gary Fowler]

Very good info for the welder just starting out and many that have been welding for years but only aware of home/ hobby type welders.

 

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