I have to weld some 409 stainless steel plate 3/16" thick to a galv. 2" x 8" x 3/8" wall tube. It had mild steel plate on it, but that warped during that galv. process, so we are cutting that off and replacing with the stainless steel. First is there a code procedure that covers this? We are planning on using 308 mig wire. Sound reasonable? Thanks for your input.
Well if you think that mild steel warped, that stainless is gonna look like a horseshoe by the time your done welding it on galv. tubing wth a shotgun welder. Gotta weld it to hot to get through the zinc coating. Try grinding off as much zinc as possible. You will know bacause the sparks change colors. Then use a 309 alloy filler for the deposit material. SMAW is what I have the best luck with because GMAW will pinhole and foam up from the zinc, but of course there will be more advise coming your way. That is the best way I know how. GOOD LUCK!!!
stainless and galvanized material is bad, bad mojo...can "almost" guarentee cracking. you'd be far better off with a piece of carbon and cold galvanizing it.
Damn good advise jon just giving him options on the material he wanted to use.
I would have to agree with Jon about the stainless and wire would not be my choice for welding either. Cold galvinzing will work good if you rough-up the plate or sand blast it before you apply it.
"Bad, bad mojo."
Couldn't have said it any better or any clearer than that.
Best regards - Al
I'll third the "Bad Mojo". I have used this to demostrae the ability of PT to show things you can't see.
I'll have to give that a try.
Best regards - Al
Shiver my timbers!
Even if you made a good weld , highly improbable. zinc can cause solid metal embrittlement (SME) cracking of stainless steel, resulting in a catastrophic failure at any time in the future.
Forum
