Welding of P91 valves to P91 piping: removal of internal components

[gabry1]

Hi everyone. I'd like some help with the following:

In case of welding of P91 gate valves to P91 piping is it recommended to remove the internal components (bearings, gasket,...) due to the high temperature reached during the PWHT at 755 Celsius ?

I don't have any details of the maximum allowable temperature of each internal component. According to the Vendor there shouldn't be any problem; on the other hand removing the internal components can create further issues with the guarantees I believe.

What are generally the reference technical documents for a process like this from the valve manufacturer ?

Considering the temperature of 755 Celsius at the welding joint, what will be the temperature in the valve if it is small (1 or 2 inches) or big (10 inches for instance) ?

Thanks

 

[metengr]

I would follow the advice of the valve supplier. Most reputable valve manufacturers have specific requirements to be followed for installation of valves with PWHT, regardless of base material.