stress relief a vessel

[eegyman5000]

if a P No.1 vessel is heat treated as a client requirement
(thikness 16 mm)
after that it was needed to fix a plate on the shell from OUTSIDE the, plate will be welded by fillet weld
will this impact the forgoing stress relieving process
and if we should re-PWHT,should this be applicable to wole vessel or just newly welded area of fillet weld

 

[metengr]

Yes, if the client requires it. Review ASME Section VIII, Div 1 UW-40, and UCS-56 for local PWHT guidance.

 

[vesselfab]

sometimes the user will forego the local PWHT if the additional weld is perfomed in accordance with UCS-56 with proper preheat and the weld size is small.

But since this is a client requirement, he will have to approve the procedure. And the AI will have to approve welding after PWHT as well.