mig gas mix

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Can I use pure argon or not to weld steel?  Most things I read say co2 /argon mix. Some say I cn use straight argon.
Reply:Some swear by it, odds are you'll swear at it.Tough as nails and damn near as smart
Reply:Are you welding alum? If so, then yes use 100% argon. If mild steel use 75/25 or 100% CO2Dynamic MetalworksMontrose, CODynMetalworks.com
Reply:I would love to know what people think about this aswell . A welding mate of mine who welds for a living every day swears by pure argon for mig and tig . But once again some say yes some say no .
Reply:No problem with pure argon with MIG on thin sections, however you will need higher currents to achieve similar results to that achieved using Ar / CO2 mixes. The CO2 is mixed gas promotes a hotter arc and improved fusion characteristics. For MIG up to 18% CO2 works best for dip / spray / pulse applications. Above 18%, globular arc characteristics increase, with an increase in spatter at lower curents and reduced spray transfer at higher currents.100% CO2 is known as MAG welding. Low end current is horrible and high end will only give globular arc characteristics with spray transfer never achieved.Because spray or pulse arc offers little to FCAW, 100% CO2 is preferred in many simple applications, however Argon 25% CO2 has many benefits with respect to achieving spray transfer at higher end currents in FCAW.CheersCheers
Reply:I've tried pure argon on steel with my HTP 200 mig.  It barely penetrates even at max voltage setting.   To effectively use this gas to mig steel, you need a very high output machine.  200 amps isn't enough.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Short answer: No.Longer answer:  No, using pure argon as the shielding gas for GMAW welding of steel is not recommended.  Pure argon is, however, the correct shielding gas for GMAW welding of aluminum.  That or some argon-helium blends for higher output on thicker sections.  The best laid schemes ... Gang oft agley ...
Reply:Thanks for the info.  I will go with the mix. Is there a link I can go to get a more indepth explanation?  I am by nature very curious and just wondering why, if the gas is inert for shielding,  why the difference?  I am really interested in why higher current is required. I was just hoping to have one bottle, but I will get the mix tomorrow.
Reply:Miller, Lincoln and ESAB all have online training classes in all 3 processes and you will learn a bit about shielding gasses by taking those self study classes.   You may also go to the websites of some gas suppliers and learn more.  Lincoln has a number of welding books that too may shed more light on your gas questions.  You may also eat a steady diet of beans and cabbage and do some experimenting with gas on your own.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:LOLMight be explosive tho....Argon will work, and amps are not the whole story, it's arc voltage that will need to be higher at any curent if pure argon is used.Mixed gas is the way to go for GMAW using hobbyist machines for sure, CO2 15%-20% is best.Cheers
Reply:I've learned alot from this thread,I get that happy happy joy joy feeling inside.Drink a Guinness Draught....Millermatic 140Do you still rememberDecember's foggy freeze --when the ice thatclings on to your beard isscreaming agony.
Reply:Don't forget the wire. There are some more compatibly than others. I prefer 90/10 mix. I'll have to look up the wire.Don't let that iron in your lungs, turn to lead in your @$$!!!!
Reply:ER70S-6 is the standard solid mig wire for use with shielding gas.  Most 110v migs will run .023 and .030 fine and smaller 220v migs will run .030 and .035 fine.  200-amp and larger migs can run .045.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by chrispc66LOLMight be explosive tho....Argon will work, and amps are not the whole story, it's arc voltage that will need to be higher at any curent if pure argon is used.Mixed gas is the way to go for GMAW using hobbyist machines for sure, CO2 15%-20% is best.Cheers
Reply:Interesting that some sources indicate NOT to use Argon when MIG-ing mild steel... yet it IS used when TIG-ing mild steel.   hmmmmmm...Lincoln AC225 & MigPak 140, Lincoln Magnum SpoolGun, Miller Spectrum 375-X Plasma, Syncrowave 200 TIG, Millermatic 252 MIG, Miller Digital Elite, General 7x12" horiz/vert bandsaw, 3' box/pan brake, 20 ton press, milling machine, 12x28 lathe, etc.
Reply:Originally Posted by AquafireInteresting that some sources indicate NOT to use Argon when MIG-ing mild steel... yet it IS used when TIG-ing mild steel.   hmmmmmm...
Reply:Originally Posted by DmaxerNote that when using tig with argon shielding, DCEN is the norm; whereas in mig, DCEP is used and some CO2 is added to the argon.  The main characteristic of DCEN in mig is that 70% of the weld heat is concentrated in the wire electrode.  With the heat concentrated in the wire, the arc needs some help gaining penetration into the base metal, hence the use of CO2 added to the shielding argon.  The characteristics of tig using DCEP are: 70% of the heat is concentrated in the workpiece, 30% of the heat is concentrated in the tungsten electrode, deep penetration and a narrow weld area.  With such deep penetration due to using DCEP, tig does not benefit from CO2 added to the shielding; indeed any added CO2 will serve to oxidize and destroy the tungsten electrode.
Reply:GitardedIF you are stuck, primarily use TIG, or weld thin material, you can use 100% argon for mild steel (and of course it is required on Aluminum).  As suggested, you will have to change the welding parameters to compensate for the pure argon (expect to have penetration issues), and that the chemistry of the weld will be different (not critical for most mild steel generalized applications).  For small, home hobbist style MIG machine's, an Argon/CO2 mix with 15-25% CO2 would be best.   This would allow you to run solid wire and some gas-shielded flux cores.
Reply:I have used 100% argon on mild steel for about 12 years or so, using .8mm and .9mm wire on a 235 amp (240 Volt) Unimig, the reason I did it was I didn't want have to have a different gas bottle when I used it on stainless, aluminium and steel. Using it on Aluminium it is what you are supposed to use, on the different types of stainless it gives different results, however on mild steel and also stainless it generally doesn't give a really nice weld, the weld is considerably higher and more knots in it as well as not giving as good a penentration, you will need to crank up the voltage and also the current considerably more to build up enough heat than you would using the correct gas mixture.The welding arc doesn't produce enough heat to smooth out the weld, as for it's strength, well over the years using straight Argon, I have built many things ranging from trailers to my last project which was a 10mt x 12mt x 3.2mt carport/garage. I have never had a weld fail on me yet but that also would also depend on your welding ability, I have had up to three times the weight in my trailer that I was supposed to have without anything going "crack". After building my garage/carport the continous increased amps/volts on my Mig were having it's toll on it and after repairing it a couple of times, I updated to a different mig and as I no longer need to weld aluminium, I switched to Blueshield 23, which is a tri-gas, it does thin to thick steel really nice and apparently will do stainless as well, although I haven't tried it so I won't comment on that yet. Check out one of my other posts and there are 2 pics of 8mm to 10mm plate single pass welded using this blueshield gas. Hope this helps.Last edited by Ed.; 01-27-2010 at 07:01 PM.Miller Auto Invision 456 + S-62 wire feederC6240B1 Gap bed lathe16 ft3 air compressor16 speed pedestal drillHafco BS-912 Bandsaw
Reply:http://www.weldreality.com/MIG_welding_gases.htm  REQUIRED READINGI've had a chance to work before with Ed Craig, Don't get me started on his site formatting, he knows his stuff back and forth and has literally written the book on shielding gasses.  If I remember I'll post a paper I wrote, during my internship on the various affects of shielding gasses on MIG welding.For the basics:yes you can use 100% argon, usually people don't because of the cost, and the sluggish nature of argon welding. Sometimes when less penetration is wanted 98-2 (98% AR 2% CO2 or Oxygen) will be specified and that's usually the gas of choice. they won't go 100% because of the slightly rougher starting and fluidity issues you may have. But it's completely possible to.Out in industry we use a mixture of AR/CO2  75/25 is a common one for the home hobbyist, where splatter and bead appearance isn't great. Some people still hobble by on 100% CO2 but it's use has fallen out of favor mostly due to appearance and the limited parameter range you get. CO2 does give a "hotter" weld and at the exactly same settings you'll get more penetration which might be nice.CO2 over ~18% will not let you spray transfer, and make your short circuiting transfer look worse. For many code applications you're only allowed to spray transfer and you have to use a mixture. Personally I specced 85/15, but 90/10  and 95/5 all work. Now when we leave steels, part of the reason you can't use CO2 is because in the plasma the CO2 breaks down into O2+C  basically free carbon and oxygen. This can cause stainless steel to oxidize, and actually causes metals to suck up carbon, which may be highly undesirable. That's why you'll never see CO2 being used on stainless (even though it helps with the sluggish welding).The final factor is cost. CO2 is a very common waste gas while Ar is usually recovered from cryogenic generation.  That means it's much more costly. 75/25 offers good penetration for home hobby units and is cheaper than 85/15 so it will be used more often. 100% Ar is even more expensive and offers no real advantages on MIG steel so you'll never see it's use.