PHT on name plate due to stress relieve 1

[jtseng123]

Dear all,

Stress relieve is required for fiber elongation exceeding 5% for CS. We have a seamless head needs stress relieve.

Referenced to UG-116(f)(2), our AI states:

"The PWHT means Post Weld Heat Treatment and it does not includes Stress Relief. When the head was performed S.R as per UCS-79(d), was there any weld seam on the head?
If your answer is yes, the letter PHT on the Nameplate is correct but if your answer is no, the letter PHT on the Nameplate is incorrect. ".

Is the statement correct ?

 

[metengr]

Well let's see...

Here is the referenced paragraph

(f) See below:
(1) The letters HT shall be applied under the Designators
when the complete vessel has been postweld heat
treated as provided in UW-10.
(2) The letters PHT shall be applied under the Designators
when only part of the complete vessel has been
postweld heat treated as provided in UW-10.

Now what does UW-10 state

UW-10 POSTWELD HEAT TREATMENT
Pressure vessels and pressure vessel parts shall be
postweld heat treated as prescribed in UW-40 when postweld
heat treatment is required in the applicable part of
Subsection C.

The above is for welds. So, your AI is correct.

 

[c8829]

Thank Metengr for your explanation.

Does it still require to follow stress relieving temperature(for post forming heat treatment of seamless head)as per Table UCS-56-1 to UCS-56-11 for post WELD heat treatment requirements.

Thanks.

 

[metengr]

Yes.