Need tips on welding 1-inch 316L

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I have a job coming up welding 1-inch 316L stainless steel. It calls for 1/4-inch fillets.  It is not a structural weld so to speak, nor is it a sanitary job.  It will however need to remain strong, look good when it’s done, and stay that way.  I will be using my Lincoln Electric PM-256 MIG welder for this job, and all the welds will be performed in the 1F or 2F position.  There will be approximately 220 inches of weld by the time the job is done.  Q: Can I use 316LSI MIG wire, or is 316L the only real choice?Q: Is 90 percent helium/8 percent argon/2 percent CO2 really the best gas for short-circuit transfer, or would 97.5% Argon +2.5% CO2 work just as well?Q: Do you, from experience, have a gas mix that welded 1-inch 316L, and resulted in a good looking weld with no corrosion?  Q: Will a 2 pound spool of .035/ 316L MIG wire be enough?  Q: At 15-20 CFH, with a wire feed speed of approximately 300 IPM, will a full 80 CF tank be sufficient to finish approximately 220 inches of weld?  On paper it looks like way more then enough, but I want to be sure (the job is time sensitive, and the gas stores are closed on Sat/Sun).  Q: Do they make a 2-pound spool of 316L that will fit the Lincoln Electric Power MIG 256, or is there another option without having to buy a 10 pound spool of 316L/ 316LSI?Q: Would using an aluminum heat sink help with warpage like when welding aluminum and using a copper heat sink?Q: After the pieces are welded, would using heat to raise the temp of the entire part help relieve stress so when the clamps are removed, warpage is minimal?  What temp would be best for 1-inch 316L to relieve the stress?Q: What respiratory precaution should I consider.  The welding will be done in a garage with good ventilation, and I plan on wearing an under the hood respirator with the pink "2091 filter."  Should I consider a welding fume extractor as well?I know this is a lot to ask for, but figured I might as well throw it out there just in case someone had the time/ experience to help.  If this has already been covered elsewhere, a link would be appreciated.Thanks,GarLincoln Electric, Power MIG 256Hypertherm Powermax 45 Miller Dynasty 280DXSmith O/A torchGenesis of a welding table
Reply:Check your manual to see if the friction hub comes off your spool spindle. If it does, a 2 lb. spool will fit. Otherwise I can't help you with mig welding it because I personally would tig it.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Originally Posted by shovelonCheck your manual to see if the friction hub comes off your spool spindle. If it does, a 2 lb. spool will fit. Otherwise I can't help you with mig welding it because I personally would tig it.
Reply:Did some research, thought I would add this should anyone else ever need the info.Stainless Steel MIG wire selection:A grade that has a “Si” designator, indicating a higher silicon content, will provide more puddle fluidity.  Examples would include 308LSi, 309LSi and 316LSi wire.GarLincoln Electric, Power MIG 256Hypertherm Powermax 45 Miller Dynasty 280DXSmith O/A torchGenesis of a welding table
Reply:Q: Is 90 percent helium/8 percent argon/2 percent CO2 really the best gas for short-circuit transfer, or would 97.5% Argon +2.5% CO2 work just as well?For short arc MIG, decent looks, etc. use tri mix.98/2 okay with pulse MIG--splattery, etc. with short arc,which is akin to welding with straight argon with a touch of CO2 that's supposed to help--but does very little.Blackbird
Reply:If you are doing fillets on 1" plate in the 1F or 2F position, there is no reason to use short-circuit transfer. Your PM256 has plenty of power for spray transfer, which is what I would use in that situation. The 97.5% Ar/2.5% CO2 mix would be close to ideal, and there would be no spatter if your voltage and wire speed are set correctly.I would not use heat sinks on heavy plate. In fact, I would use some pre-heat- not necessary for metallurgical properties with stainless,but for better penetration and less distortion. Additionally, clamping both pieces firmly and leaving them clamped until cool to the touch will minimize distortion. Many other useful tips in Lincoln's Procedure Handbook of Arc Welding.As always, let us know how it goes, and post plenty of pics!JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:John,I considered spray transfer, but wont that add more heat...and therefore more warpage?  I agree, Lincoln's Procedure Handbook of Arc Welding is a great resource.  I was looking at it last night.  It did recommend preheating for a job like this.GarLast edited by Gar; 06-07-2013 at 03:50 AM.Lincoln Electric, Power MIG 256Hypertherm Powermax 45 Miller Dynasty 280DXSmith O/A torchGenesis of a welding table
Reply:It is generally true that spray has a higher heat input than short-arc, but that is not necessarily a bad thing. If you need to produce a sound weld on 1" plate, there is a minimum amount of heat required to assure adequate fusion. That heat will cause a certain amount of distortion which has to be accounted for in your preparation and fixturing.As many have pointed out in these forums, it is easy with short-arc MIG to make welds that look good but lack strength. That is why short-arc MIG is not a pre-qualified procedure in most structural welding codes.Controlling distortion is a bit of a fine art and requires some experience, but you can't let worries about distortion lead you to make welds that are inadequate.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:SMAW (stick) and 316L stainless steel, a match made in heaven!  -Just the root pass mind you.  . Attached ImagesLincoln Electric, Power MIG 256Hypertherm Powermax 45 Miller Dynasty 280DXSmith O/A torchGenesis of a welding table
Reply:In my opinion, I would use the spray transfer with 98ar/2oxy. I highly doubt you would put enough heat in it to warp it out with fillets that size. Clamps should suffice if your that worried about it. Plus the spray will lay some beautiful welds. That 316lsi is absolute butter
Reply:Originally Posted by Pipesnake164In my opinion, I would use the spray transfer with 98ar/2oxy. I highly doubt you would put enough heat in it to warp it out with fillets that size. Clamps should suffice if your that worried about it. Plus the spray will lay some beautiful welds. That 316lsi is absolute butter