Clad Tubesheet for High Temperature application
Clad Tubesheet for High Temperature application
(OP)
Please can the forum members advise on suitable carbon steels for Hydrogen service 465 Centigrade tubesheet design according to ASME UHX and please note the tubesheet is clad. Is the cladding ignored in the design calculations for the thickness? Cladding is stainless steel. Does the Hydrogen service require any additional checks (e.g. embrittlement?)
Regards
MikeG7
Regards
MikeG7





RE: Clad Tubesheet for High Temperature application
Cladding should not be included in the thickness for Part UHX calculations. It can be treated as corrosion allowance although this presents some difficulties such as when a pass groove is used, and with any uncorroded output data.
Can't remenber offhand but your design temp may put you in the time-dependent property region, if so, particular requirements in allowables and in Part UHX calculations come into play.
Maybe a lo-alloy would be a better choice.
Regards,
Mike
RE: Clad Tubesheet for High Temperature application
I haven't done much creep work so I am not sure, just a question: Are the time dependent (creep) requirements not already taken into account in the reduced allowables?
Sorry, but I don't get what you mean by "uncorroded output data"? Please clarify.
Thanks once again
MikeG7
RE: Clad Tubesheet for High Temperature application
By uncorroded output data I am referring to any "New & Cold" data (such as MAWP) that may be calculated. For example if cladding is treated as corrosion allowance, the thickness it represents is assumed to be present, but its allowable is assumed to be the same as the base metal. Any calculations based on the new thickness are therefore not correct. True, the errors may be small, but they will be present.
I have not seen software that will account for the difference in allowables as per Part UCL-23(c).
Regards,
Mike
RE: Clad Tubesheet for High Temperature application
Regards
MikeG7
RE: Clad Tubesheet for High Temperature application
RE: Clad Tubesheet for High Temperature application