Welding of Duplex Tubes to Inconel 625 tubesheets.

[TysonS]

I am trying to get some information on welding Duplex Stainless Tubes (P10H) to Inconel 625 (P43)tubesheets for use in air-cooled heat exchangers. Is it possible to weld these alloys together? And what specification of filler metal would one employ? This will obviously be a GTAW procedure.

 

[stanweld]

Yes they can be welded together. Use ERNiCrMo-3 welding filler metal. You could also use ERNiCrMo-4 or ERNiCrMo-10. Recommend a 250F max interpass temp.

 

[metengr]

Make sure you qualify this welding procedure per ASME B&PV Code Section IX guidelines, and I would suggest a tubesheet mock-up be used for the procedure qualification.

 

[EdStainless]

You want enough Ni in the filler so that the weld is fully austenitic.
I would also suggest a filler with Ti and/or Nb for stabilization.

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