Is there a mulifunction gas for both SS & Mild Steel

admin

I am looking for a gas that I can use for both Stainless & Mild Steel.  I only have one bottle which is a 125cf tank and wanted to know if I could use a SS mixture for mild steel.  I realize that I would be paying more for the SS gas but I don't weld enough to warrant purchasing/renting/storing another bottle so I was hoping I could use one for both.Thanks
Reply:Are we talking about mig welding here?
Reply:Yes Mig.
Reply:98% argon/2% oxygen. The mixture doesn't work the best at lower parameters (difficult to short circuit) but it work good for spray transfer.Martin MC Weld TechAWS-CWIAWS-CWEwww.linkedin.com/pub/martin-cramer/20/b36/940/
Reply:I'm guessing if he's asking this question, his machine isn't big enough to run spray..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I have a fabricator 181i so your correct, I can't spray
Reply:GMAW on stainless and carbon steel, in short-circuit mode, with just one shielding gas?Not really.If you don't care about the stainless actually being stainless after you weld it, you could use C25, same as for the carbon steel.  But that's not really right now, is it?Stainless in short-circuit transfer mode is pretty much recommended to use tri-mix (helium-argon-CO2).Stainless in spray mode can use 98-2 (argon-O2).One gas to weld them all?  That would generally be argon, with GTAW.    The best laid schemes ... Gang oft agley ...
Reply:I've been using 75/25 for carbon and stainless mig/flux for years and NEVER had any issue with contamination or code issues what so ever. I've got weld procedures for stainless with 75/25. All our welds have been hardness tested, all kinds of NDT, PMI'd etc and no one has ever said anything about it. YES, tri mix welds better for the stainless mig, but dont bother. (All above pertains to short-circuit)      Doug
Reply:Originally Posted by freshintulsaI've been using 75/25 for carbon and stainless mig/flux for years and NEVER had any issue with contamination or code issues what so ever. I've got weld procedures for stainless with 75/25. All our welds have been hardness tested, all kinds of NDT, PMI'd etc and no one has ever said anything about it. YES, tri mix welds better for the stainless mig, but dont bother. (All above pertains to short-circuit)      Doug
Reply:I have also used 75/25 on stainless in the past when it was the only gas available.  It welded and looked ok, but developed some light surface rusting along the edges over time when exposed to the elements.  I have never tried it in spray mode.Miller Syncrowave 350Millermatic 252/ 30A spoolgunMiller Bobcat 225g w/ 3545 spoolgunLincoln PowerArc4000Lincoln 175 Mig  Lincoln 135 Mig Everlast 250EX TigCentury ac/dc 230 amp stickVictor O/AHypertherm 1000 plasma
Reply:The closest thing to a "multifunction" gas would probably be 95% Argon / 5% CO2. Not the best for short-arc steel, though, especially out-of-position.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:The mixture doesn't work the best at lower parameters
Reply:freshintulsa,C25 might work in Tulsa, but it doesn't work for crap along the coast (salt water).I question why anyone would go to the expense of using stainless steel in the first place, if they're going to contaminate the weld with the introduction of carbon in the covering gas.SS welds (short arc mig) done with C25 WILL rust.I do marine fabrication/repair.  Last year I had to totally redo the entire bridge railing for an imported trawler that had been repaired using mig, SS wire and C25.  EVERY joint that had been repaired FAILED.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:One option to consider.There are dual shield flux core wire that will run stainless with C25.  The flux inhibits the nromal carbon chromium reaction.   The wire is very expensive though.  Cheaper to buy another bottle!I have no idea how it runs, just know it exists.   Esab I think.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Wow. Well, I doubt much of the vessels I weld with 75/25 go to salt water, they are in refineries. All our compressor skids, panels, etc. we tig. Now, if you read the OP's post, I highly doubt he will be doing anything worth the hassle of another bottle. And, no, none of my welds have any signs of rust on them from being out in the weather. Just the other day I saw a tank I welded a year and a half ago sitting outside the shop (customer changed directions so we built another one) and no rust anywhere. Now, we do blast the tanks after welding, maybe that helps, i dont know. The only rust I've seen on stainless has been from cheap low grade stainless (304) or from using carbon grinding disks. So, If the original poster is just looking for something to weld some stainless with, use the 75/25. If you have a particular job and want to be anal, get some tri-mix. I would still use the 75/25. Oh, and I've had no issues with oxidizing or poor weld appearance. We dont allow poor looking welds. No issue with rust, color ( I can even get a hint of color almost resembling a tig weld on stringers) or oxidation. Doug
Reply:Well I got anal and bought a tank 125 CF tank from CL and exchanged it for the tri mix --90% helium 7.5% Argon and 2.5% Carbon Dioxide.  Now I have a bottle for SS, and a bottle for mild steel.   I think if I knew how much the tri mix was going to cost I wouldn't have minded the rust too much.Thanks for all the input.