PWHT
PWHT
(OP)
In what conditions there is a need (must) for heat treatment of complete pressure vessel?
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RE: PWHT
RE: PWHT
Regards
r6155
RE: PWHT
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: PWHT
Now, if one is to envision a PHWT of the welds only, then the state of stress in the vessel would be quite interesting. Certainly worthy of an FEA to evaluate the stresses during PWHT. And said FEA would likely indicate that the PHWT will leave yield level residual stresses when completed. In other words, such a proposal is likely to be completely impractical for the vast majority of cases.
RE: PWHT
Regards
RE: PWHT
It can only be w.r.t. the welds, otherwise it wouldnt be called Post Weld Heat Treatment. HT (Heat Treatment), with a different purpose, may also be specified as per VIII-1. Think for example of certain alloys which are formed beyond a certain strain limit (see UNF-79). However I dont think this HT is done in the same step as PWHT.
RE: PWHT
See UW-40 (a)(1) heating the vessel as a whole in an enclosed furnace.
This procedure is preferable and should be used
whenever practicable.
Regards
r6155
RE: PWHT
Yeah, I get that, but my point is try to imagine heat treating only the welds without heat treating the rest of the vessel. For example by using electric resistance heaters placed only on the welds and HAZ. Not something I'd like to try!
I think with ikarga's clarification, the answer becomes "If the client said "PWHT" then thou shall assume it means the entire vessel. If the client wanted a vessel with only certain parts PWHT, then they would have taken the time to call that out specifically."
RE: PWHT
Regards
r6155
RE: PWHT
Thank you for your efforts, especialy to r6155 - UW-40(a)(1) was crucial for Client.
Thank you all
Regards
RE: PWHT