Mig Welding Stainless to mild steel

[markh]

Is it possible to mig weld stainless to mild steel? Thanks

[Sabre]

yes..... i welded some stainless vacume tube together once to make a forge....think it works fine...i was having a hard time but i think that was kuz i was usin a gassless a the time

[Thomas Dean]

309 wire with 100% Argon, you can use 310 wire also

[Jose Gomez]

You can use regular old mig wire (ER70 S2 or ER70 S6) and 75% argon 25 CO2, or even straight CO2, if your not concerned about corosion resistance. just weld it like regular steel,but with one difference. You need to be sure to shield the back side of the weld with shielding gas, or backing paste, if the stainless is thin enough for the weld to penetrate all of the way through the material. If the back side of the weld puddle is left unprotected (if air can get to it) and the weld penetrates all of the way through the material you will end up with a brittle (contaminated) weld that will not stand up to any abuse.

[Thomas Dean]

True, you can even weld copper with E70s wire, it's just not as good a weld. I kinda figured if you were welding theses 2 dissimilar metals together you would want a good weld. As Jose recommended, you will need a backshield if your stainless is thin.

[Woody]

one thing I learned welding Stainless Steel Dome Risers into Acid Tankers years ago is that the stainless disapates the heat faster than the carbon steel and if you are not careful the weld will crack right down the middle.

[tompdw]

You could use any common steel wire but it would bring the carbon out of the stainless and cause it to rust. 309 is for stainless with dissimiliar steels and 308 is for stainless to stainless and I think you need a trimix gas. Not positive though.

[unkle spike]

First question: What KIND of Stainless, 304 or 409 or something else?

That would determine what material you would use as the filler wire.