Additional welding after PWHT
Additional welding after PWHT
(OP)
Dear Engineers
I have a quck question about additional wleding after PWHT
and Hydro test completely.
present situation is as follows.
In a vertical pressure vessel of ID3000mm, shell Thk 17mm
herewith, one of Internal supporter (T10mm x 50mm) was attached with 8mm fillet welding and then, this support was revomed as per client requirement.
In this condition, client ask for additional requirement as follows as per their precess requirement.
- PWHT again
- Hydrotest again.
However, this requirements is not related to ASME requirement, but only for process condition.
I have a quck question about additional wleding after PWHT
and Hydro test completely.
present situation is as follows.
In a vertical pressure vessel of ID3000mm, shell Thk 17mm
herewith, one of Internal supporter (T10mm x 50mm) was attached with 8mm fillet welding and then, this support was revomed as per client requirement.
In this condition, client ask for additional requirement as follows as per their precess requirement.
- PWHT again
- Hydrotest again.
However, this requirements is not related to ASME requirement, but only for process condition.





RE: Additional welding after PWHT
http://www.welding-advisers.com/
RE: Additional welding after PWHT
Was there additional welding or grinding on the VESSEL SHELL after it has been postweld heat treated & hydrotested?
RE: Additional welding after PWHT
This internal stiffener was attached after PWHT and Hydro Test, and then this stifferner was removed again by Grinding.
RE: Additional welding after PWHT
I would also mandate an NDT (like wet fluorescent MT) of the base metal heat affected zone after local PWHT, in lieu of a hydrotest.
IF this vessel is under construction, and before ASME Code stamping, you will probably need to PWHT the base metal heat affected zone, and perform a second hydrotest to apply the ASME Code stamp.
RE: Additional welding after PWHT
Is it also required Local PWHT and Hydro test again.?
RE: Additional welding after PWHT
Process requirement is only for NACE and Sour service as we know.
RE: Additional welding after PWHT
I would do what your client is asking for. By welding on the vessel after PWHT, you have reintroduced residual stresses that might cause in-service cracking of the vessel.
RE: Additional welding after PWHT