Selection of electrodes for AISI 409

Date 03-30-2007 21:18

Estimado amigo si vas a soldar inoxidables el material de aporte como minimo debe ser de la misma claidad que el metal base. Ahora si vas a unir inoxidables con otro tipo de acero estructural recurre al diagrama de schaeffler.
Saludos
Erik Sandoval

By chuck meadows (***)

Date 03-31-2007 13:36

409 is considered a "second generation" ferritic stainless steel. 409 is lower in chromium and carbon, but have powerful ferrite formers added to the melt. The ferrite former added to the 409 is titanium. Another name for the 409 is "pseudoferritic" because of the additional ferrite former other than chromium. The filler metal used would probably be the matching 409 or 409Cb. I don't think there is a 409 or 409Cb listed in A5.4, though. The only SMAW ferritic electrode for welding the ferritics is an E430, but it does not contain any stabilizers such as Ti or Cb. 309 and 309L are the most common austenitic grades used to weld 409, although E312 and E310 are also used. Now, the choice is up to you..

By Boon

Date 04-01-2007 05:31

Can we also use electrode E316L-17, which we have in stock, for stainless steel 409.

By chuck meadows (***)

Date 04-01-2007 13:11

I'm sure you could probably use the 316L-17 if that is what you choose to do. It is not quite as strong as a 309L, and has slightly less chrome, but it is up to you. The moly in the 316L-17 will give added pitting corrosion resistance. So, maybe it is a trade-off. Personally, I would not be afraid to use the 316L-17 electrode. I'm sure your weld test will let you know if it will work, but I think you're OK.

By MDG Custom Weld (***)

Date 04-02-2007 09:39

Chuck,
I don't have the exact AISI 409 chemistry, but why would you prefer to weld it using 309 or 316 alloys? Don't you thing the added Cr would form brittle Cr carbides along the toes and fusion line, and promote carbide precipitation along the HAZ? Maybe the AISI has higher Ti that would tie up the C and not cause an issue. Is there any risk of low melting intermetalic alloys in the grain structure from dilution mixture?

Thanks for the information.
Mark

By chuck meadows (***)

Date 04-02-2007 16:40

The only ferritic stick electrode is a 430, so if one doesn't want to use that, either an austenitic or nickel alloy should be used. Carbide precipitation (sensitization) should not be a problem with a low carbon material. When welding ferritic material, there aren't a lot of choices since there aren't that many ferritic filler metals made. If he said he wants to use 316L because that's what he has available, I think there shouldn't be a problem.