Dear all,

I am designing a pressure vessel per Set. viii Div. 1.
1. The heads of this vessel are seamless and will be cold forming.
2. After calculation as per ucs-79, the head need to be heat treated after cold forming.
3. The whole vessel will be PWHTed as per ucs-56.

It seems that the heads need to heat treated two times.
Question: May this vessel only perform PWHT as whole as per ucs-56 instead of Heat treatment requirment as per ucs-79 ?
Thanks
john

Yes.

Interpretation: VIII-1-95-50
Subject: Section VIII, Division 1 (1992 Edition, 1993 Addenda); UCS-79(d)
Date Issued: March 13, 1995
File: BC94-684

Question (1): A cold formed head has to be heat treated to fulfill the requirements of UCS-79(d) in Section VIII, Division 1. Does the term "heat treated subsequently" mean just after forming and prior to any other operation?
Reply (1): No.

Question (2): If Reply (1) is no, then will PWHT in accordance with UCS-56 satisfy the requirements of UCS-79(d) following welding of the head to the vessel?
Reply (2): Yes.

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