MIG Gas Mixture for steel

[vinceb]

I've been welding AL with my millermatic 211 and have a small mild steel job. Can a good weld be had useing 100% argon with ER70S-6 wire?

[H80N]

I've been welding AL with my millermatic 211 and have a small mild steel job. Can a good weld be had useing 100% argon with ER70S-6 wire?

The answer is NO...

take a look at the chart, figure 2-9 pg 12 in this booklet

http://www.millerwelds.com/pdf/mig_handbook.pdf

[aametalmaster]

All i am going to say is try it. I have and can make good welds with it ...Bob

[H80N]

If you are asking if you can get away with it???

then the answer is "probably"

but is it reccomended??.... nope..

[kristian]

argon

You should use a 75% 25% mix

[vinceb]

For a small job, it would be nice to not have to get a bottle of C-25. Do you think that the penetration will just be less with the 100% argon?

[aametalmaster]

but is it reccomended??.... nope..

Why? ...Bob

[H80N]

Why? ...Bob

Bob
here is an old thread that goes into it in more detail, although it wanders quite a bit..(lots of old threads on this subject)

http://www.millerwelds.com/resources...mig-with-steel

Here is a link to the Praxair gas selection manual.... it goes into which gases are used to what purpose and why (Chapter 4 covers GMAW/MIG)

http://www.prest-o-sales.com/other_l...n%20Manual.pdf

[aametalmaster]

Here is a link to the Praxair gas selection manual.... it goes into which gases are used to what purpose and why

http://www.prest-o-sales.com/other_l...n%20Manual.pdf

Page 38 is the same picture i have in my Modern Welding Book but that still doesn't convince me. Built some die racks that prob hold a few hundred thousand lbs 11 years ago from 1/2" thick I beam, .045 mig wire a Miller Deltaweld 452 and argon gas and its still in use today. Sure its not textbook but it will work. Just my thoughts...Bob

[H80N]

The guidlines seem to be pretty consistant about the use of pure argon on mild steel MIG....
it is not a suggested usage.......
People ignore the guidelines every day..... sometimes it works for them... sometimes it does not..... but I would think there were sound reasons for their conclusions in the first place......

Bob
I am just the messenger... so frankly I do not care what somebody does.. and I have no interest in fighting over it... have fun doing whatever you like...however you like..

just be aware that industry standards seem to be counter to the use of pure argon in mild steel MIG... The Miller MIG handbook, the Praxair Handbook and all the others that I have found suggest various mixes with Co2 for better wetting of the puddle and elimination of undercutting for this application... No place that I have found Specs pure argon for welding mild steel....
maybe I have just not dug deep enough.....

[flukecej]

Argon not meant for LIGHT WEIGHT WORK

I used a Miller 22A Wire Feed on a Delta Weld Machine at a Former Employer. We could make the prettiest welds on material 1/4" and heavier all day long. However, because of the ARGON, we could never turn the machine down enough to weld 1/8" or lighter. If it was more than a tackweld, it blew right through the metal. For Spray, Heavy Fab, building a 3" shaft backup for machining, worked great. For building side rails for a trailer with 10 guage Formed C with 14 Guage formed side fence, didn't work at all.

For the MM211 to do a decent job on thin metal, get a 80 CF bottle of CO2 or Steel Mix (75/25) and "Get-Er-Done." I keep an 80 as a backup when my 120 comes up empty. Used to use a 220 but changed to smaller tanks for ease of handling and transport.

[SundownIII]

People go against conventional wisdom/industry standards every day and sometimes get away with it.

Sure as he11 doesn't make it right or something that you should recommend to a newcomer.

I guess there are some posters who think they're smarter than the machine manufacturers and the companies that make the wire. I have NEVER seen a creditable source recommend straight argon for short arc mig welding of mild steel.

I'm not even going into a drawn out description of what the addition of CO2 does to the weld, since it's been published many times in numerous references.

If the OP is "really" concerned about cost, then he'd be better off just picking up a really small bottle of CO2. The CO2 will give him better penetration than the C25 anyway.

[davedarragh]

The MM-211 is basically a "short arc" machine, and needs a minimum of 20% CO2 to support the arc. C-25 or 100% CO2 would be the gasses of choice. As an alternative, if it's a small job, and the expense of a small bottle of new gas isn't in your budget, a 2# roll of E71TGS self shielded flux core wire can be purchased for less than $20. Just be sure and switch the polarity on your machine.