High pressure flange material

[belfour30]

Hello,

I do not have access to B16.5 but I would like a reality check on a slip on flange that would be capable of 550F and 5,250psi. In my table of service ratings for SS not even CL-2500 flanges can get that hot. Any thoughts?
Thank you.

 

[metengr]

belfour30;
According to B16.5, the appropriate flange for the stated service conditions would be

Group 1.10 (SA 387 Grade 22, Class 2 plate or SA 182 F22 Class 3) 2500 lb Class

@550 deg F, 5290 psi working pressure

interpolation is permitted between 500 and 600 deg F.

At this pressure, I would NOT recommend a slip on flange. You should be using a welding neck flange.

 

[belfour30]

metengr - thank you for all of your help with my questions - it is most appreciated. These requests for pressure vessels are becoming more and more frequent so I'm trying my best to wrap my head around it.
In your opinion, can I perform decent "reality checks" of designs BEFORE going to my ASME machine shop with an actual RFQ with the following:

ASME Section VIII/Division 1
ASME B16.5 for flanges
ASME Section II/Part D

I cannot purchase the entire code nor would I want to learn it. I just want enough information to put a decent design together. To give you an idea of what my company does - we put heating elements inside vessels of all shapes and sizes. Frequently we are using a piece of pipe with flanges welded at each end. Therefore, all I would really need to know is the stress values for lots of different materials (Section II/Part D), the service ratings for flanges made from different materials (B16.5) and then obviously the construction of these vessels (VIII/1).

Am I making sense? Could I get away with this level of reference material or would you recommend something else?

Again, thank you so much for your help.

Matt

 

[metengr]

belfour30;
If I understand your post correctly, what I believe you intend to do is to develop a "conceptual design" that would be used as a request for proposal. An ASME certified shop would review your conceptual design, develop final design and fabrication details for your review, fabricate and stamp the vessel.

If the above is your intention, yes this makes sense. You can use the above to narrow down the selection of material choices for the shop. Ultimately, the ASME certified shop is the one that will assume design responsibility and fabricate the item to ASME B&PV Code.

 

[belfour30]

My regular pressure vessel shop cannot recommend designs that would be suitable for 525F/5,125psi for a 2.5" and 1.25" pipe. I need to maintain the ID for these pipes with a standard sched. 40 thickness (ie, 2.469"ID and 1.28"ID respectively) - but I don't care if the pipe needs to grow outwardly, so if it's a 4" pipe with a .765" wall thickness, that's fine. Is this design just not feasible with any construction?

 

[metengr]

belfour30;
The concern is safe and long term pressure retaining capability for the 2.5" and 1.25" pipe sizes.

Is this design just not feasible with any construction?

No. It means the wall thickness must be increased for a specific pipe OD or a higher strength pipe material must be used. This is not a growth problem, it has to so with avoiding stress rupture failure in service.

 

[belfour30]

Sorry, when I say "grow" - I mean from a design standpoint. If I need a 10" pipe size bored out to give me the intended ID I need (for what goes inside the pipe later) that's no problem. Subsoquently if I need 10" flanges that is fine too. Primary design needs to have a 2.5" ID and be able to withstand 525F/5,125psi.

 

[metengr]

Run the wall thickness calculation using Section VIII, Div 1 and see what you need and evaluate material allowable stress options.