PWHT duplex cladding

[Errewin]

Vessel to be cladded (GMAW/ FCAW and ES-strip cladding) with duplex. PWHT is needed for basemetal. Consequences for the duplex cladding?

 

[GRoberts]

If PWHT is in the "normal" temperature range for C.S. PWHT, (say between 1000-1200F), then you will get lots of intermetallic precipitates and might as well not have duplex cladding to begin with. Its corrosion resistance and mechanical properties will be severly impaired.

 

[Carburize]

With the expense of the cladding operation and post weld heat treatment is the cost of the overlay material that significant?
Is a nickel base material like Inconel 625 too expensive?

 

[stanweld]

If this is an ASME Section VIII, Div 1 vessel, can you perform overlay after welding and PWHT of the vessel shell? Or is this a Section VIII, Div 2 vessel?

 

[Errewin]

Thanks for your answers.
We decided to propose a thin (3mm) "625"-cladding. The (1 layer) overlay with 625 can be realised thinner than with duplex or 904L. Also higher cladding speed is possible with 625, there dilution% is not critically with 625.