We are fabricating a pressure vessel of 45mm thk; with PWHT;RT-01;Welded construction. After stress relieving/PWHT does it require to carry out RT again(already RT taken before SR)? If RT is not possible can it be substituted by UT? What is code reference.

You do not need to repeat RT after PWHT. Ask who says the contrary to quote the Para. requiring it.
Mauro

Hi,

there is no requirement for the time of RT in ASME VIII/1 (before or after PWHT, except as required by UHA-33(b) and UHA-33(c)). Regardless to the time when RT is performed it needs only one time to perform RT (see also Interpretation VIII-1-98-09R).

If RT is not possible it can only be substituted by UT as follows:
-for final closure seam of a pressure vessel according to UW-11(a)(7)
-for all seams according to Code Case 2235.

_________________
Kind regards,
Juergen Fleischfresser