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MIG Welding - 100% Argon?

39K views 15 replies 10 participants last post by  D_CeLiRaToR  
#1 ·
Will 100% Argon work fine for MIG welding? Reason being is I would like to share a bottle between the MIG and TIG welders. I _think_ it is a silly question since Metal INERT Gas and CO2 is not inert but I want to check.

I know argon is more money, but I don't weld enough to care.

Chris
 
#2 ·
This question doesn't have enough information. I am assuming you are speaking of steel.

Argon alone CAN be used however it is very difficult to elimintate the undercut that can be generated and the weld appearance can be bad.

You can stick things together with it. IT is not used in industry that I am aware of. On machine welds using spray transfer and high travel speeds it may be possible. There is usually a small percentage of O2 added. I have performed Semi-Auto GMAW using 98 Argon with 2% O2. The higher the argon content, the lower the amperage required to "SPRAY".

What I would suggest it to try it.

For Aluminum, it works fine.
 
#4 ·
This is from praxairs website at http://www.praxair.com/praxair.nsf/.../d63afe71c771b0d785256519006c5ea1/f406fc8ace1333648525656100775f5a?OpenDocument

Argon
Argon (Ar) is used on nonferrous base metals such as aluminum, nickel, copper, magnesium alloys, and reactive metals, such as zirconium and titanium. Argon provides excellent arc welding stability, penetration, and bead profile on these base metals. When welding ferrous-based metals, argon is usually mixed with other gases, such as oxygen, helium, carbon dioxide, or hydrogen.
 
#5 ·
This is my experience, so take this for what it's worth. I have used pure argon and mig to weld up farm implements on occasion. The beads are taller and narrower. I have no clue what the difference in strength (however you want to think of strength...) is between a typical 75/25 weld and a pure argon weld. The welds I made were simply to get things back in service with the stuff I had at the time. They were all in flat position, with only a couple of exceptions. As Gaustin says, the transition to spray happens at lower amps. The welds have held for at least a couple of years, and at most 5 without any failure that I know of. Most welds were on 1/8 - 1/4 inch plate on bushhogs and the like, so no real serious stress on that stuff, but at least one was on a gang plow that must have been at least 3/4 inch that I had to do in several passes, and it does undergo some fairly rough treatment. No problems yet...

Remember, this isn't a recommendation, just information.
 
#7 ·
On thin sheet metal I tried 100% argon, bead apearance was not as good and did not get consistent penetration. On thin stainless though the 100% argon was better than argon/co2.

Bottom line you can make do non critical stuff anyway with 100% argon for mig though 75/25 is better for general steel work, you can't make due with 75/25 for TIG.
 
#8 ·
Pure argon for TIG.

Pure argon for MIG on aluminum.

Argon blends (Ar-O2 or Ar-CO2 or Ar-He-CO2 or etc) or pure CO2 for MIG on steel.

Using pure argon for Mig on steel is not recommended. I flat-out asked Lincoln's behind-the-scenes tech folks the same question. The flat-out answer is Nope. The same question/info/answer has been asked and answered here more than once, and also on ESAB's website, on Lincoln's website, on Miller's website, on Hobart's website, on the wire suppliers' sites, etc, etc.

Problems could include poor fusion, inadequate tie-in, a very-very narrow finger of arc penetration, a humped-up ugly bead, an erratic and/or unstable arc, poor (at best) or unknown deposit properties, etc.

And "MIG" is a slightly 'outdated' term, because the acronym is not inclusive of the many non-inert gases used in the shielding. Hence the 'full' acronym is actually GMAW, gas metal arc welding.

For short-circuit transfer on steel, C-25 or pure CO2 work well. If you want to do spray or pulsed spray on steel, you need a lower level of active gas in the mix, but you still need -some- in there. Could be 1-2% O2, or up to about 15% CO2, or whatever, but GMAW on steel pretty much needs that 'active' component in the gas.
 
#11 ·
Ummm, Roger,

C25 is a recommended shielding gas for short-circuit GMAW.

GTAW uses pure argon for steel, aluminum, brass, copper, etc. Occasionally a mix of argon and helium is used for GTAW.

No using C25 for TIG, you'll toast your tungsten.

No using pure argon for GMAW on steel, use the C25 or other blended gas.

Yes to using pure argon for GMAW on aluminum.