Heat Treatment After Forming

Hi everyone,

I would like to clear myself about heat treatment of forming head.

- My design for pressure vessel requires PWHT

-At the same time, ellipsoidal head forming also requires heat treatment due to elongation after forming.

- Now one of my colleague request me that they want do only one time of PWHT after fabrication the whole vessel. When I check ASME section VIII Div1, UCS 79, the code pointed to follow as per UCS 56(PWHT).

-So the question I want to know is,

(1) Can I accept to make only one time of PWHT for whole vessel and Forming of head?

(2) If Yes, please which points I should take care to control?

(3) If No, please let me know the point why I can't accept and the section of ASME I should refer.

Thanks a lot for your help.