forged steel screwed fittings 2

[razzendahcuben]

I'm a CAD user being assigned a piping job... so I'm getting a little overwhelmed by terminology.

I have to create a parts library for several "forged steel screwed fittings" sizes (according to NPS). Right now I'm just working with 90 deg elbows.

Moreover, my specs sheet only gives an A and B with a picture almost identical to this:

http://www.bonneyforge.com/specs/fittings/threaded_90.cfm

The specs are not exactly the same, however, so I know that the "forged steel screwed fittings" I'm working with are not exactly the same. Nevertheless, these are called "threaded" whereas mine are called "screwed." What's the difference?

Continuing on: Is there a way I can find out the dimensions for the flange? On the same site I found specs on the flange of a very similar looking elbow, only it is called a "socket weld" instead of "threaded".

http://www.bonneyforge.com/specs/fittings/socket_90_elbow.cfm

Would this page be of any use to me in determinining flange values, or is this "socket weld" entirely different from the "threaded" version?

Any information would be appreciated.

 

[pennpiper]

razzendahcuben:
I pity you if you are a CAD operator and have never had any basic technical training in piping. You will find a lot of terms you will not understand.

You said you are creating a parts library for AutoCAD. You don't need to create your own. These libraries already exist. go here:

http://www.pipingdesigners.com/downloads/Autocad.htm

You wrote: "Nevertheless, these are called "threaded" whereas mine are called "screwed." What's the difference?"
There is no difference. Threaded fittings have threads and are screwed together.

For a catalog of the different flanges go here

http://www.texasflange.com/Dimensioncutsheet.htm

To help you with some of the basics of piping please go here:

http://www.pipingdesigners.com/Training.htm

and read everything you see there . Print all of it out and start yourself a Piping Training manual.

 

[razzendahcuben]

Thanks for the help! The trouble is that I'm using SolidWorks, not AutoCAD. SW doesn't have a very big fittings library.

I'll check out the links, but if you don't mind I'd like to get a few things sorted out:

Can you explain the difference between threaded, socket welded, and butt welded fittings? The latter two have a shoulder, whereas the threaded fitting does not, correct? And the seal is formed at the shoulder rather than with a tapered thread?

If you can answer those I think I should be set. Thanks so much.

 

[LUDPEKA1]

Take a look in the SW forum, you might be able to find someone that is willing to share or be able to point you in the direction of some existing fittings.

http://www.eng-tips.com/threadminder.cfm?pid=559

 

[JLSeagull]

See FORGED FITTINGS, SOCKET-WELDING AND THREADED
ASME B16.11-2001. For piping terminology, I regard the term threaded to be the same as screwed. I am sure that others will clarify if this is not so.

 

[StevenHPerry]

Your best bet is to go to the source, like Seagull says.

ASME B16.5 (flange), B16.9 (weld fitting), & B16.11 (forged fittings) to start.

I've found those dimensions to be more inclusive than most commercial catalogs.

 

[pennpiper]

razzendahcuben:
You wrote:
"Can you explain the difference between threaded, socket welded, and butt welded fittings? The latter two have a shoulder, whereas the threaded fitting does not, correct? And the seal is formed at the shoulder rather than with a tapered thread?"

No! this is not quite correct.

I will try to correct your thinking.

Both the screwed and the socket-weld fittings have a shoulder like band around the connection point. You can consider these thickened shoulders as a reinforcement of the connection end. This "band" tends to makes up for the material cut away when the threads are cut for the screwed fitting and for the drilled out socket for the socket-weld fitting.

Go to:

http://www.pennusa.com/pennpage/directory/forgecat/forgcatl.htm

For details on more screwed and socket-weld fittings.

Screwed fittings have inside (female) threads. The pipe for screwed piping has outside (male) threads. To make a joint the pipe is threaded into the fitting. Depending on certain commodity and design conditions pipe dope or Teflon pipe tape is used to help seal the joint.

Socket-weld fittings have a hole (socket) drilled in the connection end of the fitting. The diameter of this hole is the same diameter as the outside diameter of the O.D. of the pipe (plus a little clearance). The pipe has a plain end cut. The pipe is slipped into the socket to the bottom. Then it is pulled back 1/16" to allow for expansion during the welding process. The weld for a socket-weld fitting is a single fillet weld completely around the joint, sealing the connection.

Butt-weld fittings do not have a shoulder or reinforcement. The connection end of a butt-weld fitting has a "Beveled" end. This bevel is normally made by machining during manufacturing. Butt-weld fittings have a consistent wall thickness much like pipe. There are some exceptions but these are not important for what you are doing right now.

Butt-weld fittings are joined to pipe or other butt-weld fittings by a "full penetration weld." The term "full penetration" means that the weld is the full thickness of the wall of the pipe/fitting.