Buttering 1

[3lilaggies]

Looking for information on buttering. Welding on carbon steel doing a Overlay of 316 SS. Would it be a good idea to butter first with some 309 SS? Needing to stay within the limits of ASME Section VIII and IX. Any help or Guideance would be appreciated.

 

[Goahead]

It would be not only a good idea but an essential one to avoid problematic compositions.
You could use either 309 or 312.

http://www.welding-advisers.com/

 

[GRoberts]

If you use 316 over carbon steel, depending on dilution, you will end up with some martensite in the weld deposit. (In the 3-phase A+M+F region of the Schaffler diagram) This shoud be avoided due to the propensity for cracking. The 309 with it's higher alloy, (and again depending on dilution) will normally put you into the A+F region. As long as you are in the primary ferritic solidification (i.e. more than about 3-4FN) part of this region, it is fairly crack resistant.