Welding SA-312 TP321H pipe to SA-182 F9 Socket Weld Valve 1

[MDS N SONS]

I've got the subject scenario to do. I need to qualify a weld procedure. Planning on 400°F preheat and 1350°F or so PWHT. Having some difficulty picking the best filler metal. Line will be in high temperature steam service. I was thinking either going matching the lower alloy and using ER80S-B8 or the higher and use ER347H. Third choice would be ER309 or ER309Mo.
Any suggestions?

 

[metengr]

Yes, I would suggest using one of these ERNiCr-3, ENiCrFe-3, ENiCrFe-2, ENiFeCr-4 (Code Case 2734) and ERNiFeCr-4 (Code Case 2733) and avoid the 347H and 309 filler metals because the DMW will fail prematurely from carbon migration along the P9 side of the DMW. The B8 filler metal is not an option because of dilution.

 

[MDS N SONS]

OK, we typically use ERNiCr-3 for some of our other dissimilar procedures so I'll probably go with that. Am I on the right track for preheat and PWHT?

 

[metengr]

Yes. The 321H tube material is high carbon for creep strength so exposure to PWHT is not an issue for this application.

 

[MDS N SONS]

Got it. Thank you Metengr!