Welding Stainless Steel

admin

What methods (wire,stick,tig) can be used to weld stainless steel?Which, if any stand apart from the other, would be best?Would you need a special rod or wire to weld stainless steel? I would guess you would need a stainless steel metal in the rod or wire for it to be effective, but thats just me guessing.Thanks,Darrell
Reply:Have a look at the post titled 'Stainless Spillway'. It's in the Welding Projects forum.Scott
Reply:He did a nice job on the spillway. He used TIG. Ok now I need to know what do I need to run TIG off my Bobcat? It has the setting for TIG. Would I need an adaptor for the torch? I havent TIGed in over 20 yrs so I'll be like a beginner again learning the process. But I did learn to TIG before I learned to stick and wire weld, just havent done it since.I could find out from Miller.
Reply:you can stick S/S just get some S/S rodChuckASME Pressure Vessel welder
Reply:Depending on how thick the base metal is and what type of joint you are attempting, you can tig stainless without filler rod...in fact, that's true for most metals that you typically tig.  It's not too hard to weld SS...but then again, I havent done a whole bunch of stainless...there are a lot of different types and I have experience with just a few.  It's just not a metal that I use often.I also know the guy that owns the company that supplies the ss diswashers to waffle house.  He said that they use all mig machines to assemble the stainless sheet metal...He said that if you get the settings right, you can't tell the difference between mig and tig (his words, not mine)...I don't know so much about using stick.  There are rods, but I dont have any experience with them.For SS tig on a bobcat, I think you just need a torch with the right connectors (air cooled ones now run up to 300 amps) and a bottle of argon.  I think scratch start is do-able, but you may want an HF starter.  For stick, you just need the right rods.  For mig you just need the right wire and argon.Back purging is an issue with some applications...so, you probably want to find out if you need to do that.Last edited by smithboy; 03-13-2006 at 07:37 AM.Smithboy...if it ain't broke, you ain't tryin'.
Reply:for mig on stainless its best to use argon oxygen blend for corrosion resistance 98/2. for tig straight argonBTS Welding
Reply:I have done a lot of tig with a gas drive- usually a trailblazer, not a bobcat, but the principle is the same.First, get a scratch start tig torch with a gas valve in the handle.Plug it in where the stinger goes.Then get a tank of argon, and a flowmeter.You open the valve first, and make sure argon is flowing, then scratch start. If you stick the tungsten to the work, you need to regrind it. again, and again, and again.You need to remember to turn off the gas when you are done welding. Argon is expensive. Then you need to remember to turn ON the gas again when you start up again- or you are back to regrinding that tungsten.If you do very much of this, you start to realize why people break down and spend the big bucks on a HighFReq unit to be able to start the arc without scratching.But to begin, a 150 dollar or so scratch start torch will do the job. DC. EP.
Reply:Ries hits a couple of things that are really important...the gas valve is absolutely necessary if you dont have the solenoid (which I think you don't).I have wasted a good $30 of argon by forgetting to turn it off.  Luckily never the whole bottle.  Little leaks are real killers.Smithboy...if it ain't broke, you ain't tryin'.
Reply:I can tell you welding stainless with mig is the fastest process if  you are not applying it to a sanitary application that requires a certain amount of polishing to rid the weld of scratches,pits,and just plain rough areas where food hangs up in the washing process and breeds bacteria. Sometimes you go as far or further than a 400 grit finish tig will give the desired bead to grind and finish in this application in my humble opinion.   One thing to watch is distortion while welding Stainless it warps alot worse than low carbon steel. In the mig process the puddle freezes faster than carbon steel welding therefore the human errors we all cause in the puddle show up worse in the stainless beads. Its not that far a leap to run stainless if you weld carbon steel pretty well with a mig. Remeber to know what grade stainless you have there is many but a few i know are 304,308,316, you really should use the same grade wire.  Which process you use depends on what your making I would think. Hope this helps
Reply:Try stick welding before you invest in new equipment. You might be surprised at how good it works. I have an old 30 lb box of MIL 308-16 SS rods I brought home with my dad's SA200. One of the 12 cans was open - had been for ~20 years. I needed to weld some 304SS pipe for a tractor exhaust so I tried one of the opened rods (the flux was cracking) to see what it would do. The weld looked beautiful! (for me) Little to no splatter. I ended up welding up the whole exhaust pipe with the flaky rods. I did learn not to get impatient and chip the slag while the weld was still hot (hot SS will oxidize). Of course this was not a critical application, I just had to weld the pipe to the original carbon steel flange and weld the tube back together where I had cut out a wedge to make a bend. SS transfers heat poorly so the heat stays concentrated in the weld area. I think that can be good but may be the reason for the warping mentioned by SNT. I am not a pro welder but I hope this helps. Brad
Reply:I buffed it a little. Attached Images
Reply:Brad,Those test SS stick welds look very good. Do you remember the settings(amps, polarity, stick diameter)? Thanks,Don
Reply:Evidentally a lot of people aren't aware that companies in the welding industry  publish booklets specifically listing the types of metal (in this case  Stainless ) & the recommended  electrodes , or welding wire for each type. they are free or low cost . If your local supplier is not stocking these or is too ignorant to know what you need , by all means contact the manufacturer ; they are happy to help . for beginers , i think $20 bucks or so , spent on a Lincoln  Arc welding book  , or a junior college welding text book  is very well spent . (just my opinion)
Reply:It was about 55 amps, DCEP, 3/32 stick.