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Oxygen service

Oxygen service

Oxygen service

(OP)
Does anyone have a feel for the use of AISI 4340 in high pressure oxygen?  This is a pressure vessel rated for 30,000 psi at ambient.

RE: Oxygen service

There is a NASA standard for HP O2.
Also an airforce one, but I don't have addresses handy for either.

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Plymouth Tube

RE: Oxygen service

metalonis;
At 30,000 psi pressure this better be a code stamped pressure vessel. What are you going to do with 4340 alloy steel and this vessel? Is is being used for pressure boundary applications?  

RE: Oxygen service

(OP)
I've been working with high pressure vessels for 30+ years, so I'm well aware of the mechanical aspects of vessel design.  This is an existing design, not yet put into service.  Our customer now asks if it can be used in pure O2 service.  What I'm unsure about are the corrosion and/or failure considerations of an oxygen/alloy steel interface.

RE: Oxygen service

My point to the above is not mchanical aspects of design it is material aspects of pressure vessel design and ASME B&PV Code does not approve the use of 4340 steel as pressure  retaining material, regardless of environment. So, bottom line is this, you cannot use this material for Code-stamped pressure retaining applications.

For high pressure oxygen bottles, at ambient temperature high strength low alloy steel pressure vessel plate is acceptable.
 

RE: Oxygen service

(OP)
Thanks guys!

RE: Oxygen service

Most of these that I have seen are made from PH grade SS (17-7, 13-5, C455 and so on).   

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Plymouth Tube

RE: Oxygen service

metengr,

Out of curiosity, why does the ASME B&PV code not allow 4340 steel for any PV apps?  Does the provision for "high strength low alloy steel" specifically identify ferritic microstructures, or are tempered martensitic microstructures also allowed?

RE: Oxygen service

There are plenty of low alloy steels suitable for high pressure oxygen service in ASME Sect VIII, Div 3.   Corrosion of low alloy steel at strengths necessary for 30ksi application is always an issue due to the possibility of HISCC.  Some alloys are less susceptible than others, I will leave that to you to decide which is best.  But, there are hundreds if not thousands of vessels made from SA508 or SA723 material in high pressure (> 30 ksi) applications containing hydrogen.   As long as you design and fabricate the vessel to ASME Sect VIII. Div 3 requirements you should be OK

RE: Oxygen service

TVP;
For pressure vessel applications there are two uses; the first is pressure retaining function where the material is used under primary and secondary membrane stresses or as part of the pressure boundary (retaining). The second application deals with trim or non-pressure retaining function. It is under this application where any weldable grade of steel can be used.

Very simply, the reason 4340 steel is not specifically approved for use is because the carbon content exceeds 0.35% by mass. Material that is considered suitable for use must exhibit good weldability characteristics in addition to ease of fabrication and strength/ductility.

 

RE: Oxygen service

Thanks!
 

RE: Oxygen service

metengr,

Further to TVP's question, what if you are making a cylindrical tank without welding and would like to use a high strength steel?

RE: Oxygen service

CoryPad;
Regardless, you would need to use one of the Code approved materials listed in Table 1A in Section II, Part D of the ASME B&PV Code if this is for pressure retaining service.
 

RE: Oxygen service

OK, thanks for the answer.

RE: Oxygen service

I was thinking the same thing as CoryPad, but didn't post the question.  What if I were an enterprising young man and wanted to produce such a high strength cylindrical vessel, sans welding, using a steel such as 4340; could I work with the ASME B&PV Code gods to have a new provision written for non-welded applications, as long as the proper development was done, testing performed, high-quality presentation with real engineering data was given?

RE: Oxygen service

You would likely have to do a proof test (destructive pressure test) as well as determinign the material is suitable for the proposed environment.  

RE: Oxygen service

Quote:

I was thinking the same thing as CoryPad, but didn't post the question.  What if I were an enterprising young man and wanted to produce such a high strength cylindrical vessel, sans welding, using a steel such as 4340; could I work with the ASME B&PV Code gods to have a new provision written for non-welded applications, as long as the proper development was done, testing performed, high-quality presentation with real engineering data was given?

Yes. It would require a Code Case for submittal. The Code gods may lend some pitty on an enterprising young man in the name of safety first, and not just for business needs.

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