mig welding 409 stainless

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im welding 409 stainless 18g with .35 wire now heres my question can i our how do i get the gray out of the weld? we have been playing with heat, speed, different gun angles. but it just  turns a dark gray. am i just stuck with gray coloring? any body have ideas?
Reply:Its a gas coverage issue. What gas are you using? I would use a tri mix with flux core stainless. I am guessing that you are not using a flux core and as you move the nozzle, you lose gas coverage while the metal changes states from a liquid to solid.UA Local 598
Reply:im using a 95-5 mix 95% argon 5% co2.. we are welding in a production setting. so that could be the problem.. but for cost wise i think the company wants to run that mix... the tri mix are u talkin like argon co2 and helium?
Reply:You should research the wire you're using and find out what gas the manufacturer says to run it with.  In other words, get the product ID number and call the wire mfg'rs customer service number.   Doesn't matter what the 'company' wants to use, the manufacturer knows what works.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:18ga with .035 wire? I bet using a smaller diameter wire will help, because I doubt on that thin of material gas coverage is going to have any effect.  You need to lower the heat input.Either switch to a pulsed/RMD power source or invest in a good acid cleaner.Even with good gas coverage and proper speed/heat getting good color when MIG welding thin stainless is quite hard to accomplish.  What is the joint setup like?Have we all gone mad?
Reply:From my experience with pulsed MIG on 300 series stainless, 95/5 Ar/C02 is good choice, or 98/2 Ar/O2, no problem with oxidation of the weld.  It could be you taveling too slow, with a low power input, so that excess heat is building up around the weld, and the weld is still too hot as the torch and shielding moves forward.  A hotter faster weld results in a smaller heat affected zone and faster quenching from the surrounding base metal.  Not sure about your application, but I would try a push angle of around 20 degrees, crank up the amps to allow you to move around 30 inches per minute, and considr adding copper heat sinking to the joint and/or auxillary shielding behind the weld.  Protect the hot weld, or cool it before it needs protection.
Reply:X2 on 95/5 Ar/CO2 or 98/2 Ar/CO2.  Not a fan of oxygen mixes, although they do smooth out the arc.  I don't recommend tri-mix for welding thin stainless.  Too much added heat required for such thin metal.  Burn through problems will get worse with tri-mix.0.035" dia filler metal seems too big for 18 gage sheetmetal, but that's what Miller's weld calculator recommends, assuming you're using solid SS filler wire.http://www.millerwelds.com/resources...calculator.phpBenson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:i should mention that its not all 18g we sometimes weld 16 also.. so they dont wanna buy different wire for both.. i agree with u guys the tri mix would be better. but the big wiggs say they treid that with no change.. (i doubt it). ill post pics on here to let u guys get a better look at what im doing... I dont think travel speed is the issue becouse we are in a prodiction atmosphere. hince we haul ***. haha.... ill contact the wire manufacturer tomarow and see what they say....INK & IRON
Reply:0.035 solid wire on 18 ga?  Seems a bit on the big side, unless you are running some sort of pulse action.Even doing some 16 ga I think that 0.030 solid wire would be plenty.  0.023/0.025 would probably be big enough too, and give you a little more 'balance' on amps and filler deposition rate and bead size and travel speed.And +1 on what the wire manufacturer says.  The filler specifics can vary and favor or just flat-out require certain gas(es) over others.And 409 is just -barely- stainless, as you probably know.  A bare minimum of chromium (10.5 - 11.75%) is the only thing that makes it 'stainless' at all.  Other than that, it is just a tiny bit of carbon (0.08% max) to make it steel and not just iron and max 1% silicon and max 1% manganese.  Plus trace 'contaminants' like sulfur and phosphorus.  The rest is all iron.Next, just -what- are you welding?  Tube/pipe? some sort of 'open' joint?  Lap welds on thin sheet?  You may be having gas shielding flow problems, with the gas swirling around and entraining oxygen from the atmosphere, or a bad gas hose/conection somewhere sucking in air, or too much gas flow getting oxygen in from the air, etc, etc.And depending on the physical parts configuration, a back-purge might be necessary (pipe/tube, and especially if the joint fit-up is iffy to start with).You -are- using a 409 filler with the 409 parent material?Short-circuit transfer on stainless steel -usually- uses tri-mix as the shielding gas.  Low enough CO2 that excess carbon pick-up is not a problem and argon and helium as the other gases.  The other gases mentioned are more for spray trasfer IMO.  The best laid schemes ... Gang oft agley ...
Reply:Really the only way your going to get better color on that material with that wire size is to go to a STT/RMD/CMT process.  You need to lower your heat input. You could also look at the bernard guns with centerfire consumables.  They provide a much better gas shield, almost like a gas lens for MIG welding.Have we all gone mad?
Reply:ok i got some pics to show u guys what im dealing with.. as u can see the welds them selfes look good its just crappy coloring. we do paint them after we pipe them for kits but ive got a ton of emails of people wanting that industrial look to them... i just think with bette coloring they would go for it... im sorry i forgot to get the wire brand name and info...  and that last pic i thought id throw in as a bonus i just finished a full polished header back system... Attached ImagesINK & IRON
Reply:Good looking sound welds, and the discoloration is not a relavent issue other than appearance.  I would look at improving the existing shielding or adding auxillary shielding if you want to prevent the weld oxidation.  Maybe the Benard gun sn0border88 recommended would help.  I have used auxillary shielding with automated MIG supplied through a TIG gas lens setup with the electrode hole plugged with a screw.  You have a good weld, and extra shielding will solve the problem, so you could prove this with an experiment, and then figure out if feasible to use in production.
Reply:For welds on sheetmetal (and 16 or 18 gauge is still sheetmetal  ), I'd say that the beads are bigger than needed for the thickness of the parent material.  And that ties in with more overall heat being input to the weld than is needed.  Which can lead to heat tint oxidation as the  parent material is heated up during the 'large' weld and is still hot enough to oxidize when the shielding gas pool/cloud dissipates when the torch is moved.I'd say use 0.030 wire and move up in the torch nozzle size (if possible) from say a 1/2 inch diameter nozzle diameter to a 5/8 or 3/4 inch diameter nozzle.  Or similar.  And slightly increase the shielding gas flow, but not so much as to cause worse flow turbulence or atmospheric entrainment.Because I kind of agree that the welds don't look quite as 'right' as they could/should.  A bit 'hazy' or 'frosty', possibly from a little too much voltage or too much overall weld heat or not quite enough shielding gas pool/cloud/blanket or a combination.  The best laid schemes ... Gang oft agley ...
Reply:Looks pretty hot to me, and it looks like you might be "whipping" a little bit.  Never a good idea (in my opinion), but on thin SS it can really color up a weld.  Fast is always better if heat input is a concern, and any whipping just slows you down.
Reply:we are whiping it. some of us have tried just draging it down and with no luck......im glad every body on here agreed on the gas mixture. i showd some upper managment that it wasnt just me thinking that. and next week we will be using tri mix but they still wanna use 035 wirebut hopefully the gas solves some prob thanks guysINK & IRON
Reply:Gas change might help some, but overall, I think you are too hot for the base metal.  You could back off to a 2-3% CO2- balance argon and run as low as you can on volts and amps and still get good SC transfer.  Off topic how is the weather up there.  I grew up at the other end of the lake and miss having cooler weather.  In Houston, TX now and it just now started to be ~70 at night
Reply:the weather isnt bad this week. in the 70 and 80s.... its getting cold at night tho.. supposed to have a nasty winter tho agian...hahahaINK & IRON
Reply:The Helium in the tri-mix will basically put more heat into the weld.  I don't thing that is where you want to go.One thing you might want to consider is some of the metal filler wires (expensive!) but they do take some of the worry out of MIG on stainless.  Go to the web site "www.weldreality.com" and look around.  The guy is production MIG welding genious (at least in his own mind  but he does have bits and pieces of valuable information.  He needs an editor!The gray color is typically attributed to the chromium coming out of the stainless.  What you are seeing on top is more iron, less iron + chromium.  When welding 304 stainless, and you see that on the front side of the weld, the back side usually looks like crap (chromium precipitate coming out).You need to investigate purging the back side of the weld - suggest you use pure argon.  And alternative would be "Solar Flux" but that stuff gets expensive fast.From the pictures, it looks almost like rust is forming next to the weld.  The discolorations on stainless is from the material oxidizing.  Usually its only surface oxidation layer.  If you have exposed iron, you can actually get pitting.   If it's in the budget, you can experiment with passivating the stainless.  Walter Abrassives has a hand held passivator (about $2000).  Never heard it done on 409 - mostly 3xx stainless.  Normally brownish coloration is gas coverage, too much bluing is too much heat.   When using TIG on 304, I always can tell when I end the weld that I didn't hold the torch long enough in place (with post flow) because I end up with a brown halo around the end.Bottom line, the best thing to do is avoid the oxidation in the first place, but you can chemically fix it.  On 3xx stainless I would even suggest polishing.BTW, if you are concerned about looks, why 409?  409 sucks to weld compared to 3xx and doesn't look as good (won't hold a mirror like polish).  At the end of the day, is it really that much cheaper?  I know when it comes to exhaust system, the customer wants the price of a $300 Flowmaster system, but the quality of a $1000 Corsa.  If you priced everything at $1000, you won't have a lot of customers.Anyway, I'd love to find real mufflers for larger diameter exhaust systems that are 304 stainless.  The Flowmasters are moisture traps and _WILL_ rust out (plus there are some questions about whether they are good for performance - certainly not on turbo charged engines).  All the other mufflers are glorified glass packs (straight through with some wadding around the perforated pipe).   It would be nice to find a high flow 'turbo' style muffler (like Thrush or Dynomax) in larger diameters (3", 3.5" and 4") that actually reduced the noise.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:mm not sure where u get ur info on flowmaster mufflers are not for turbo cars we make big 4 inch turbo back kits for diesel trucks with great dyno gains... and the reason we cant go 304 or the likes is the way a flowmaster muffler is built that stainless is to week to be welded like a chambered muffler is designed.. the 304 just vibrates apart after a while.. and flowmaster is going all stainless now so the mufflers will not rust out like the aluminized ones.. im going to demo some tri mix with .030 wire next week hopefully we see some better results....thanks for everybodys inputINK & IRON
Reply:I thought 409 was designed specificially for the exhaust business to give desired mechanical properties at low cost.
Reply:409 is 'designed' to be about the least expensive, least alloyed (barely) stainless steel.  It's low carbon steel with just -barely- enough chromium to qualify as stainless steel.Strength-wise, 409 and 304 are both pretty much the SAME.  Both have a 0.2% yield strength of 35 ksi, but 304 actually has a higher ultimate tensile strength of 85 ksi compared to 65 ksi for 409.  And 304 has an elongation of 55% compared to only 25% for 409.So, 304 is generally a 'better' material than 409.  409 usually just wins out on price.So if 304 can't do the job strength-wise, there is pretty much no way that 409 would do the job strength-wise either.  I would suggest that if some of your 304 prototypes or samples 'failed', it was not directly due to them being made of 304.  Poor welding like using the wrong filler (308 filler is the 'standard' for welding 304 stainless) or the wrong/poor shielding gas or a poor design or other poor workmanship would all cause possible problems that could have caused failure(s).Stainless steel sheetmetal thicknesses should be able to be welded OK with 0.030 wire and tri-mix.  At last better than some 0.035 solid wire could usually do!  It will still take some skill and practice to weld 16 gauge without having 'issues' like warping or burn-through or whatnot.The last time I tried GMAW on some plain steel 'sheetmetal', I turned it into scrap from all the warping and distortion.    I definitely need waaay more practice to be able to do that kind of work.    btw, that was with 0.030 solid S-6 wire and C25.  I probably should have changed the spool to some 0.025 wire and dialed things down some more.  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by flowmaster techmm not sure where u get ur info on flowmaster mufflers are not for turbo cars
Reply:Nice one! I like its color. It is awesome. I think that you have a great work for that.
Reply:Originally Posted by con_fuse9Just search for 'Flowmaster".[B]The only theory I know that would explain it, is that the air flow post turbo is relatively lacking of pulses. Jack Burns at Burns stainless has pointed out that must of the stock eliminator run hevy 350s (honest 350-400hp) that he builds or designed headers for are running 1.5" primary headers.   However, no one.... and I mean none of the off the shelf headers for a Chevy 350 are even available in 1.5".  So if 1.5" is optimal for about 350 - 400 hp, why is everyone buying 1 7/8 etc.? Ignorance is bliss (and I was one of those ignorant - since reformed    hopefully ).
Reply:Originally Posted by jakeaBurns achieves that power by exhaust velocity, rather than slower flowing gas with a larger volume. That coupled with low backpressure( natural byproduct of valve overlap via cam profile).