Best Choice of Weld Filler Metal??

[dsring]

What would be the best choice for weld filler metal with the following joint description: 2-1/8" x 0.150" MWT SA213-TP347H to SA213-TP310HCbN (HR3C) with a SA213-TP347H backing ring. The joint will be in service in a coal fired boiler, and could see temperatures as much as 1200 deg F. We have narrowed the choices to either using a ER347 filler, or a ERNiCr-3 (Inconel 82) filler.

 

[stanweld]

I would not recommend the ERNiCr-3 because of the coefficient of expansion mismatch and strength mismatch will promote thermal fatigue failure during both hot and cold thermal cycling.