PetroStreet

Can anyone tell what will happen to SS, if CS vessel cladded with SS is Post Weld Heat Treated.
SS will be sensitized ?

You can perform PWHT of CS vessels (more than 37.5 mm thk) or piping of CS (more than 19.05 mm thk) with SS 304L or SS 316 L caldding.
SS cladding will not be sensitized because of low carbon contents.
There is a curve called "Time Temperature Sensitization Curve" which tells about the possibility of SS being sensitized if exposed to high temperature against time. SS 304L or SS 316L has carbon contents of less than 0.02% hence can sustain PWHT temperature for longer durations like 100 hrs. and off course PWHT will not be required for such a long durations.

Thats the reason why cladding is done with Stainless Steels having lower carbon content where CS base metal exceeds the cut-off thickness value for PWHT.

Thanks Zahid.