Developing manufactured flanges from near net shape

[hubby89]

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.

 

[nickelkid]

What are the flanges for?

 

[hubby89]

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

 

[jerry1423]

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.

 

[nickelkid]

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.

 

[drawoh]

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

 

[hubby89]

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.

 

[plasgears]

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.

 

[SnTMan]

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

 

[nickelkid]

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

 

[drawoh]

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

 

[unclesyd]

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.

 

[nickelkid]

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.

 

[drawoh]

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

 

[unclesyd]

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.

 

[hubby89]

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?

 

[nickelkid]

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.

 

[jerry1423]

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.

 

[arunmrao]

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)

 

[moltenmetal]

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!