Welding nozzle into clad vessel

[KevinNZ]

Hi
We have to add a nozzle to an existing vessel. The vessel is carbon steel(SA-516 Gr 70) with 3mm 316SS cladding. The nozzle we are adding is 316 pipe. We have not worked on a cladded vessel before so would like some direction please. Weld details below. To make it more complex we have also comply with NACE MR0175. Vessel design is ASME VIII (Div=?)

1. What is the weld thickness for heat treatment requirements?
2. What PWHT is required?
3. Is a WPS for 316SS welded to carbon steel OK for this detail with the cladding?

Thanks

 

[mk3223]

Instead of an on-line opinion, you may want to consult with the Company Material Engineer for the agreement of the dissimilar metal welding on a clad vessel. IMO, the concern is the highly potential weld damage on the nozzle may be resulted from the different thermal expansion properties of two metals.

 

[KevinNZ]

Thanks mk3223.
We have asked for pointers from the original vessel designer/fabricators. We did get a little bit of information from them.

The original vessel already has a number of nozzles like this.