Legs Material For Low Temperature Vessel 1

[nashof]

Hi All,

Currently I'm designing a pressure vessel in which design temperature is -65ºC / + 65ºC (-85ºF / +149ºC).
The vessel dimensions are ID 1300mm (4.26ft) x TT 2500mm (8.20ft), and the supports height from tangent line will be 1500mm (4.92 ft).
The operation temperature of the vessel will be 0ºC (32ºF) and it will not be insulated.

Because of the low design temperature we'll use SS (SA-240 304) for shell and heads.

For the supports we are thinking about using 4 legs with reinforcing pads welded to the shell.
Legs' reinforcing pads would be done with the same material and thickness (8mm) of the shell, and legs would be done with structural carbon steel: S 275 JR.

Do you think is it appropiate to use this material for legs with the low design temperature we have?
I think, if the vessel is not insulated, and a SS reinforcong pad is used, low temperature of the vessel should not affect the legs, but please, could you give me your opinion?

Thank you very much in advance,

 

[gr2vessels]

You are correct, the legs material is not dictated by the vessel design temperature, however, the weld of the legs to the pad should not exceed the 50 MPa stress, otherwise you'll have to change to a low temp material and/or better still, to a skirt in lieu of legs.
Cheers,
gr2vessels

 

[nashof]

gr2vessels,
what do you mean with the 50 MPa as maximum? could you please explain??
tnak you!!

 

[chicopee]

50Mpa=50,000,000 N/m^2=7251.9psi

 

[nashof]

Sorry, I did not explain well, I know what 50Mpa are, but I was asking about why that limit?