PFHT vs PWHT
PFHT vs PWHT
(OP)
Hi folk, I'm having a discussion regarding PFHT/PWHT.
If a vessel is to undergo PWHT, is there the need to PFHT the heads before PWHT?
I think there is no need, but someone is asking "where it is written".
I replied asking where is written that "there is the need", but I got no answer.
So, I'm wondering: is there any Interpetation that CLEARLY allows to perform a stress releiving of a head after forming during final PWHT of the complete vessel?
Is there the need for an interpretation or it's obvious that PFHT of a formed componente can be performed during the final PWHT of the entire vessel?
If I'm righ, how to "convince" the skeptics, or how to demonstrate it with Code?
Thanks
Cristiana
If a vessel is to undergo PWHT, is there the need to PFHT the heads before PWHT?
I think there is no need, but someone is asking "where it is written".
I replied asking where is written that "there is the need", but I got no answer.
So, I'm wondering: is there any Interpetation that CLEARLY allows to perform a stress releiving of a head after forming during final PWHT of the complete vessel?
Is there the need for an interpretation or it's obvious that PFHT of a formed componente can be performed during the final PWHT of the entire vessel?
If I'm righ, how to "convince" the skeptics, or how to demonstrate it with Code?
Thanks
Cristiana
RE: PFHT vs PWHT
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.
Based on that, do you think it is possible to extend it to Div.2?
Thanks
Regards
RE: PFHT vs PWHT
If you are fabing the head and entire unit and know that it will receive a full body PWHT then there is no need to do it.
Unless you have experience that tells you that the fab goes smoother if you HT the head first.
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P.E. Metallurgy, consulting work welcomed