NDE for checking ductility
NDE for checking ductility
(OP)
What non destructive tests can be done on a carbon steel pressure vessel (liquid CO2 service) that has gone below <-20F?
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NDE for checking ductility
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RE: NDE for checking ductility
You could use a portable hardness tester to see if the material has undergone any hardnes changes since fabrication.
Presumably you want to know if brittle fracture is imminent. Acoustic Emission (AE) may help. Sensors are applied at strategic locations around the vessel, a load (static or cyclic) applied and the resulting acoustic signals received reviewed for evidence of stresses within the material. Its basically monitoring complete structures for crack initiation. There are specialist companies who perform this as a service.
Nigel Armstrong
Karachaganak Petroleum
Kazakhstan
RE: NDE for checking ductility
If the temperature reached by the material is above the minimum design temperature i don't see problem.
Also the ASME VIII (if the vessel is build folowing ASME) allows to go to a temperature well below the minimum design temperature depending on the stress ratio, without the necessity to perform impact test. (see UCS-66 of ASME VIII)
hope this help
S.
http://www.corrosionist.com
RE: NDE for checking ductility
If you indeed went below (how far below?) -20 deg F for this carbon steel vessel in-service, and nothing happened (in other words no signs of leakage or problems), I would perform a visual inspection and perform a wet fluorescent MT around several appurtenances or nozzles on this vessel just to be sure that no cracking was introduced at the time of the temperature excursion. This is what I would do for peace of mind.
RE: NDE for checking ductility
Aaron A. Spearin
ASQ CSSBB
Engineering Six-S'$
www.Engineering6ss.com
"The only constant in life is change." -Bruce Lee
RE: NDE for checking ductility
Any additional suggestions on NDE are welcome.
RE: NDE for checking ductility
Being that CO2 is highly corrosive to steel when in contact with the atmosphere (forms carbonic acid), I'd think that any cracks that would form will begin to rust fairly quickly.
Unfortunately, most CO2 vessels are insulated, making that rust impossible to locate unless you remove the insulation. You may consider doing this during your next outage, assuming there is one.
Here's a brief overview of the corrosion issues:
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RE: NDE for checking ductility
RE: NDE for checking ductility
INCOTEST is Pulsed Eddy Current (PEC) which can detect corrosion under insulation (CUI) on ferro-magnetic materials.
Nigel Armstrong
Karachaganak Petroleum
Kazakhstan