PWHT Requirements
PWHT Requirements
(OP)
I am working on a project to add some nozzles to vertical drums. Both of them were built in 1975 and the shell material is SA-285-C.
I have some confusion regarding the Post Weld Heat Treatment of the vessels. One has a 1-9/16" thick shell and the other has a 1-5/8" thick shell. The manufacturers data reports indicate that neither vessel was heat treated. According to table UCS-56, SA-285-C should be heat treated if its thickness is greater that 1-1/2"
Does anyone know of a reason why these vessels would not have been heat treated.
Any advice is greatly appreciated.
I have some confusion regarding the Post Weld Heat Treatment of the vessels. One has a 1-9/16" thick shell and the other has a 1-5/8" thick shell. The manufacturers data reports indicate that neither vessel was heat treated. According to table UCS-56, SA-285-C should be heat treated if its thickness is greater that 1-1/2"
Does anyone know of a reason why these vessels would not have been heat treated.
Any advice is greatly appreciated.





RE: PWHT Requirements
If what you are reporting is accurate, the vessels should have been subjected to a thermal treatment after long seam and girth welding. Was the heat treatment reported as a re-normalization heat treatment versus a subcritical PWHT?
RE: PWHT Requirements
Maybe somebody got paid under the table to look the other way or sheer incompetense by all parties involved.
RE: PWHT Requirements
if it shows 1 1/2" thick....it could have been preheated to skip the PWHT.
you only pwht ""greater"" than 1 1/2" thick
that is if they were code stamped
RE: PWHT Requirements
RE: PWHT Requirements
I don't know what they were trying to indicate, but it caused me quite a bit of confusion until I figured it out. Thanks to everyone for your responses to my question.
RE: PWHT Requirements
Per ASME Sec VIII UW 40, the governing thickness for determining the need for PWHT, is the thickness at the welded joint. My point being, that regardless of minimum thicknesses required for design, the need for PWHT is driven by the thickness at the weld. If I have a welded shell plate 1-9/16" thick, but, only require 1.25" for design, PWHT is required.
RE: PWHT Requirements
RE: PWHT Requirements