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Developing manufactured flanges from near net shape

Developing manufactured flanges from near net shape

Developing manufactured flanges from near net shape

(OP)
My boss has asked me to look into a procedure to produce manufactured flanges from near net shape, bar stock, or existing flanges.  We want to be able to to create a method for quickly manufactured flanges when needed quickly.    
If you take an already manufactured flange and machine it into a different size, does it have to meet any standards? Does anyone have any suggestions on how to accomplish this. or just some help in general about the subject.

RE: Developing manufactured flanges from near net shape

What are the flanges for?

RE: Developing manufactured flanges from near net shape

(OP)
We mainly use weld neck flanges and they are welded onto manifolds, steam traps, and strainers.

RE: Developing manufactured flanges from near net shape

Like RC eluded to it depends what type of flange you are talking about.

I found this is in Wikipedia
http://en.wikipedia.org/wiki/Flange

It has a few helpful links in there, it is not very intensive, but it is a place to start.

RE: Developing manufactured flanges from near net shape



Most likely you want to produce ASME/ANSI Flanges. Determine the sizes and ratings you want to produce and then go to http://www.asme.org/, flange standards are available for download for a fee. The required markings, materials, dimensions, tolerances and testing requirements are detailed in each standard.

 

RE: Developing manufactured flanges from near net shape

hubby89,

   There are all sorts of ways to produce a flange, but it depends on the size or sizes, and on the tolerances, surface finishes, materials and material finishes.  How much money are you willing to spend on tooling?

   Are you making the same flange over and over again?  Are you making a variety of flanges?  

   Can you show us a drawing?

                     JHG

RE: Developing manufactured flanges from near net shape

(OP)
Currently we use sizes from 1/2" up to 3" in pressure class of 150, 300, 600 and 900/1500.  Most of our flanges are carbon steel, and then we also have t316 and t304.  I have the ASME/ANSI B 16.5, which is our standards, with dimensions and detailed information.  We manufacture our products, so tooling wise I believe we would have the necessary tools for machining, we also do currently face and machine the weld neck of some of the current flanges we use.  
It would be a variety of flanges.  We are looking for an easy and fast way to make a flange when we are trying to get the product out the door in a hurry and we wont receive manufactured flanges in time.


 

RE: Developing manufactured flanges from near net shape

Near net shape implies finish machining in the process. Cast flanges may have gasket and weld surfaces machined. PM flanges can be mfrd so that machining is not reqd.

For the purposes that you describe, I would suggest casting with the goal of lap welding to the pipe. If you need the capability to provide various flange configurations for the same pipe size, then it sounds like a custom machining with blank flanges for later finishing of holes and flange faces.

RE: Developing manufactured flanges from near net shape

hubby89, slip-on flanges (See ASME Sec VIII, Div 1, Apx 2) w/o hub are often burned from plate, drilled and machined as required. This construction is probably most useful for moderate sizes, temps, pressures. (On second look I see you mention up to 3". My guess is that plate flanges will work for the higer rating in this size.)

I guess what you can do depends on what Code, Standard, etc you work to, and what design rules are available to define your flange.

Regards,

Mike

RE: Developing manufactured flanges from near net shape


What Material Group(s) are you providing? And what product form is being requested (Forging, Casting, or Plate).  

RE: Developing manufactured flanges from near net shape

hubby89,

   The fast and easy way to make a flange, or just about any other part, is machining.  

   Near net shape involves going to a vendor who does some form of near net shape fabrication, like casting, forging, or powder metallurgy.  Near net saves you money by eliminating machining processes and not wasting material.  Near net costs you more up front because of tooling, and the tooling and setup takes more time.  

   If you need to work fast, machining is the way to go.  If you have large quantities and you want to save money, look into some form of near net.  Any as-cast, as-forged, as-PMed surface you can live with, is something you do not need to machine.

   Do you have tricky inspection requirements?

                           JHG

RE: Developing manufactured flanges from near net shape

If I may ask  how are you going to make a new flange out of an existing one?

What is your piping code that will allow plate flanges?

A few comments>

The highest class flange I've seen form plate is Class 300. Plate flanges normally have to be calculated as loose flange due to the lack of a hub.

I've never seen a WNF machined from plate. Even if it is permissible it would take some thick plate to machine the hub on any flange.

I've never seen a flange machined from PM, nor would I want to be around one.

If you absolutely want to machine your flanges tou should workout details with a forging company to get blanks. We have bought blank flanged where we drilled the bolt holes in positions where we use many small fasteners instead of a few large ones.



 

RE: Developing manufactured flanges from near net shape

drawoh,

From a production stand point is absolutely correct.

NB with B16.5 flanges changing the material form may (and often does) have rating impact. Sometimes machining from plate is not an option.

Additionally, I do not believe Powder Metallurgy is an acceptable B16.5 material form.
 

RE: Developing manufactured flanges from near net shape

RCHandy,

   The point I am trying to make is that the OP is trying to reduce elapsed time, not cost.

   The ultimate solution is to have a dedicated CNC turret lathe with a Ø6" bar fed in through the back.  He programs in each flange.  When someone asks for a 2" flange, a worker hits a button and the flange is machined.

   Almost certainly, a drill jig for each required flange size will be needed.  All flanges will have to be the same material.

   When I ask for my flange, an unfinished, un-heat-treated, uninspected part will be on my desk within the hour.  

   This process is the antithesis of near net.  Near net is a solution to a different problem.

                             JHG

RE: Developing manufactured flanges from near net shape

I just can't see gaining anything with in-house machining standard flanges.

Unless you are in the boondocks you can have a fittings supplier have a stocking program at you site, especially for the smaller flanges.
Or do as we do have a store room that stocks all sizes up to 10" for off the shelf use. If we have a project that is going to use 50 RTJ 1" WFN we have the store room preorder said flanges. If we have to replace flange on a emergency basis our first option is the stores and the second is a call to the supply company who has 24/7 coverage.

To gain any time you will have to stock a lot of various size blanks to gain any time. Along with that, their is always the looming identification problem.

RE: Developing manufactured flanges from near net shape

(OP)
The in house machining of flanges is because the lead time on the ordered flanges is too great and we wouldn't receive them in time.  We need a fast way to obtain the flanges we need for the project.
It looks like it is best to stock near net shape flanges and set up a program to have them machined to what we need.
Is it better to stock near net flanges of the same pressure class, for instance, stock a near net shape of a 3" Class 150, and then if a 1/2" Class 150 flange is needed, machine it to those specifications? (More machine and waste of material) Stock by pressure class and machine pipe size.
Or stock more by the pipe size.  For instance, stock a 1/2" Class 600, and when a 1/2" Class 150 is needed machine to the correct dimensions and specs?  (Less machining of material) Stock by pipe size and high pressure class.
If you machine a near net shape flange into something else, does it still meet B16.5 standards?

RE: Developing manufactured flanges from near net shape

I would think that as long as you can maintain material traceability of the "near net shape" material it would not matter what flange it ends up as.

What would be best sizes of "near net flanges" to stock? Without understanding quantities to be produced and the desired investment in material on the shelf this is tough to answer.

hubby89, you must have a very unique situation. I have had to jump through hoops for some items before, but never a commodity like standard flanges.
 

RE: Developing manufactured flanges from near net shape

You also need to be careful about something else when making a flange yourself.

A forged flange has a very differnt grain structure than a machined flange, so therefore the mechanical properties will be differnt.

I assume that some of the standards that you will be reading pertain to forged flanges.

RE: Developing manufactured flanges from near net shape

hubby89,

I have been following the thread with some interest. I reiterate some of the views expressed. Casting or P/M route is not acceptable . You need to use forged or at the best machined flanges. I wonder, why you are having problem sourcing a standard item which is almost available off the shelf.Have you explored the possibilty of getting from India or China. Since most of the business is down here, it is worth trying as you may get a bargain price too!.  

Chocolates,men,coffee: are somethings liked better rich!!
(noticed in a coffee shop)

RE: Developing manufactured flanges from near net shape

arunmrao:  in normal materials like A105 and 316/L, we have little problem getting what we want when we want-  EXCEPT for reducing flanges.  There are times when a reducing flange is the right solution (ie. rather than using a reducer plus full-bore flange, or when a machined blind isn't permitted), and yet we can't get our hands on these quickly enough from local suppliers to satisfy our shop.  

Hogging whole flanges from forged bar is wasteful and requires expensive testing on the bar.

If we could obtain at very least hubbed blind flanges, but better still, full-sized weld neck flanges forged into shape without having the bore forged through, we'd be very happy.  Then we could stock a few sizes of these and machine our own reducing flanges when we need them.

None of our local suppliers are interested in supplying these to us.  And we don't buy enough to make a mill run by someone sensible.  If someone knows of a supplier we can tap into for this need, we'd be very happy!

RE: Developing manufactured flanges from near net shape

(OP)
moltenmetal,
I am trying to find full-sized weld neck flanges forged into shape without having the bore forged through too.  I have not found a vendor yet.  Have you machined your own flanges?  If so, how have accomplished this?  What standards are you using?  
We quoted a high price job and we gave a guaranteed ship date, however the lead time to receive the flanges was later then the ship date, so we need a way to obtain/machine flanges so this does not occur again.
 

RE: Developing manufactured flanges from near net shape

hubby89:  exactly the same problem we've had in past- VERY frustrating and costly!  

I am NOT an ASME expert so take what I say with a grain of salt. It is my understanding that under B31.3 you are permitted to make certain pressure-boundary components from bar provided that you do the required soundness testing on the raw material.  If I understand correctly, that's UT prior to machining, and material strength tests in both the axial and radial directions.  The process is similar to what you'd need to do to make an ASME VIII appendix II hubbed flange from plate.  This will permit you to make a flange which is safely equivalent to a B16.5 flange in terms of function- but it will not bear the B16.5 markings because it did not start out as a forging.

A code expert here may be able to quote you chapter and verse on this- and correct any errors I may have made in what I said.

RE: Developing manufactured flanges from near net shape

Flexon is a source for roller chain sprockets with hubs often fully machined from near net forgings.  I envision your flange needs might be similar.  Perhaps they would be interested in providing forged blanks.

http://web.flexon.de/index.php?id=748

RE: Developing manufactured flanges from near net shape

I just came across this thread while researching for answers to a question I had of my own.
How can bar/rod material be used in manufacturing/machining flanges (integral to the shell) for ASME code vessels.
We use Code cases 2155/2156 for justifying the shell and head, but are having problems justifying the flange this way.
Could anyone please point me to some obscure code case/ interpretation that allows this?
Please share your experiences/knowledge.
Thanks much in advance.
SP

RE: Developing manufactured flanges from near net shape

I am not sure this will help, but when I used to do this work on pressure vessel flanges for a local company.  I near netted the flanges on a flame table from A572 plate and machined them on a CNC machine with a third axis (turret had live head capabilities which we used to do the hole drilling work on the lathe).  We used this method extensively to produce parts pretty quick - I could have a flange on your dest in about 15 minutes...  I am not sure how thick a flange you need but I would seriously suggest you find a machiner in your area with flame table capabilities.  This is as close as you will come to near net from traditional machining.  If you can used ductile iron for your flanges then I would suggest that you look into a material known as Dura-Bar (Countinous Cast Ductile iron bars) - you can find them by searching for Dura-Bar on Google. This material will produce the fastest machined flanges of any standard bar-stock.

Hope this can be some help to you...

Sincerely,

Eric K.
"Strive for perfection in everything you do. Take the best that exists and make it better. When it does not exist, design it." Sir Henry Royce
 

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