Pressure vessel and creep temperature

[PaulLag]

Hi there
I’d kindly need some help for following topic.
I’d need to verify a pressure vessel for a design temperature higher than material creep temperature,ex 410F.
Question 1)
Do you think it is feasible ?
My understanding is that this is possible, but a specific number of hours, or cycles, will be determined.
After that the vessel will break.
Please, is this correct ?

Should it be possible following would be my procedure, but, if I am wrong, I would be extremely grateful if somebody could correct me.
Following would be my steps
1) Calculate longitudinal stress as
Sigma = P*D/(2*t)
2) Take the Woehler diagram for copper
3) Apply correction factors for thickness and temperature
4) Individuate which is the total number of cycles that Woehler diagram will give me for the calculated sigma (1&3) utilizing Woehler diagram


Questions
1) Is this method correct according to your knowledge & experience ?
2) Could you please tell me where to find the Wohler curve for copper ?
3) Should not, which would be the method you’d apply ?
4) Is there codified method ( ex ASME, or German AD ?) to solve this topic

Thanks in advance for your help

 

[TGS4]

PaulLag - it sounds like you need an expert on creep and creep-fatigue to help you. And you're not going to get that level of expertise for free on the anonymous internet.

 

[Paulettaa]

PaulLag, I have tried to do fatigue analysis but I have never done a creep analysis before. Anyway I think there are guidelines in API 579 (ASME FFS) that can help you.
Nevertheless, make sure that you follow TGS4 advice. Do not do this on your own.

 

[PaulLag]

Hello
First of all I’d like to thank you for your kind answer.

Agreed, I will contact an expert over this topic and I won't do on my own

Nonetheless, before proceeding, I'd like to understand at least if design of a pressure vessel for a design temperature higher than creep temperature for material is possible ?

Can anyone suggest me any link or publication I can have a look at in order to understand the design in these conditions ?
with this knowledge I could then contact in a more appropriate way an expert.


thanks !

 

[TGS4]

If you are designing a pressure vessel, then you local jurisdiction (where three pressure vessel will be installed) will have rules and regulations (laws) that will dictate what standards/codes you must follow. Follow those.

Most major pressure vessel codes around the world have provisions for construction of pressure vessels in the creep regime.

If you have no guidance from your jurisdiction, or you get to choose, I know that ASME Section VIII, both Division 1 and 2 have rules for creep (they will refer to allowable stresses in the time-dependent regime).

And API-579-1/ASME FFS-1 have rules for the evaluation of pressure equipment portraying in the creep regime.

If this happens to be a nuclear pressure vessel, then ASME Section III, Division 5 (former Subsection NH) has rules for creep.