ElCidCampeador
Mechanical
- May 14, 2015
- 270
Hi,
I'm designing a pressure vessel, O.D.1800mm, height=4500mm, mat. SS316 acc. to EN 13445.
Vessel has 2 shells (upper&lower) which are connected by a body slip on flange made by plate. Lower shell is 2,5m, higher shell 2m.
Shells are welded to 2 elliptical heads (at bottom and at top) with some minor nozzles.
My client has just changed data project for the upper shell and top head (with their nozzles): material shall be SS310, with design temperature of 675°C. Pressure is irrelevant (<1 bar).
The lower part is still designed with old material and data project (SS304 and lower temperature)
I've calculated thicknesses of all parts but for the upper shell my calculation software shows me 3 big warnings:
-See EN 13445-3 Annex M for guidance on monitoring of vessels operating in creep
-See EN 13445-3 Annex A for pressure bearing welds non allowed in creep range
-See EN 13445-2 Annex C for weld creep strength reduction factor
Calculation I've made are only to check pressure vessel parts, so what I understand is that I need to run a dedicated calculation for creep, right?
Regarding points above:
-For Annex M: it describes NDT and destructive ones during lifetime in order to monitor creep behaviour, correct?
-For Annex A: it shows what welds are allowed in creep range. Ok, no problem.
-For Annex C: I don't completely understand it, since I've no experience in creep test. It seems that tests are necessary to find parameter to be used in the creep calculation, am I right?
Do you know a sort of procedure to follow in this case, to check creep acc. to EN 13345?
Thank you
I'm designing a pressure vessel, O.D.1800mm, height=4500mm, mat. SS316 acc. to EN 13445.
Vessel has 2 shells (upper&lower) which are connected by a body slip on flange made by plate. Lower shell is 2,5m, higher shell 2m.
Shells are welded to 2 elliptical heads (at bottom and at top) with some minor nozzles.
My client has just changed data project for the upper shell and top head (with their nozzles): material shall be SS310, with design temperature of 675°C. Pressure is irrelevant (<1 bar).
The lower part is still designed with old material and data project (SS304 and lower temperature)
I've calculated thicknesses of all parts but for the upper shell my calculation software shows me 3 big warnings:
-See EN 13445-3 Annex M for guidance on monitoring of vessels operating in creep
-See EN 13445-3 Annex A for pressure bearing welds non allowed in creep range
-See EN 13445-2 Annex C for weld creep strength reduction factor
Calculation I've made are only to check pressure vessel parts, so what I understand is that I need to run a dedicated calculation for creep, right?
Regarding points above:
-For Annex M: it describes NDT and destructive ones during lifetime in order to monitor creep behaviour, correct?
-For Annex A: it shows what welds are allowed in creep range. Ok, no problem.
-For Annex C: I don't completely understand it, since I've no experience in creep test. It seems that tests are necessary to find parameter to be used in the creep calculation, am I right?
Do you know a sort of procedure to follow in this case, to check creep acc. to EN 13345?
Thank you
