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Definition of flanges

Definition of flanges

AUTHOR : _ _ Date : 3/8/2013 2:03:38 AM

  FLANGE Gerenal:

flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system. It also provides easy access for cleaning, inspection or modification. Flanges are usually welded or screwed. Flanged joints are made by bolting together two flanges with a gasket between them to provide a seal.

A typical flange connection:

Pipe flanges
are manufactured in all the different materials. Some
flanges are made of cast and ductile iron, but the most used material is forged carbon steel and have machined surfaces.


The most used flange types in Petro and chemical industry are:

Welding Neck Flange

Slip On Flange

Socket Weld Flange

Lap Joint Flange

Threaded Flange

Blind Flange

(All types except the Lap Joint flange are provided with a raised flange face.)

Most common used flange types

-- Special Flanges

Except the flanges, which are mentioned above, there are still a number of special flanges such as:

Orifice Flanges

2. Spectacle Blinds (part of flange connection)

3. Spades and Ring Spacers (part of flange connection)

Long Welding Neck Flanges

Weldoflange / Nipoflange

6. Expander Flange

7. Reducing Flange


The most common materials used in flanges  produced is carbon steel, stainless steel, cast iron, aluminium, brass, bronze, plastic et cetera.

In addition,
flanges, like fitting  and pipes, for specific purposes sometimes internally equipped with layers of materials of a completely different quality as the flanges themselves, which are "lined flanges".

The material of a flange
, is basically set during the choice of the pipe, in most cases, a
flange is of the same material as the pipe.

flanges, discussed on this website fall under the ASME en ASTM standards, unless otherwise indicated. ASME B16.5 describes dimensions, dimensional tolerances et cetera and ASTM the different material qualities.


flange according to ASME B16.5 has a number of standard dimensions.

If a draftsman in Japan or the work preparer in Canada or a pipefitter in Australia is speaking about a
Welding Neck flange 6"-150#-S40 according to ASME B16.5, then it goes over the flange which in the image here below is shown.


If the flange is ordered, the supplier want to know the material quality. For example ASTM A105 is a forged carbon steel flange, while A182 is a forged stainless steel flange.

So, in a correct order to a supplier two standards must be specified:
Welding Neck flange 6"-150#-S40-ASME B16.5 / ASTM A105

• Check all kinds of pipe fittings

1. Elbow:
45 degree elbow
45D CS butt weld elbow    45D SS butt weld elbow   45D socket weld elbow   45D threaded elbow
90 degree elbow  
90D CS butt weld elbow    90D SS butt weld elbow   90D socket weld elbow
   90D threaded elbow     street elbow
180 degree elbow  
180D CS butt weld elbow      180D SS butt weld elbow

2. Tee:
CS butt weld straight tee   CS butt weld reducing tee   SS butt weld straight tee  SS butt weld reducing tee  socket weld tee   threaded tee
   Lateral tee:
CS butt weld lateral tee   SS butt weld lateral tee   socket weld lateral tee   threaded lateral tee

3. Cross:
CS butt weld straight cross   CS butt weld reducing cross   SS butt weld straight cross   SS butt weld reducing cross   socket weld cross   threaded cross

4. Reducer:
CS concentric reducer   CS eccentric reducer  SS concentric reducer   SS eccentric reducer

5. Cap:
CS butt weld cap   SS butt weld cap   socket weld cap   threaded cap

6. Stub end:
CS stub end   SS stub end

7. Coupling:
socket weld full coupling   socket weld half coupling   threaded full coupling   threaded half coupling

8. Union:
socket weld union   threaded union

9. Socket insert:
A  B

10. Plug:
hex head plug   square head plug   round head plug

11. Bushing:
hex head bushing   flush bushing 

12. Nipple: 
TBE   PBE   TOE&POE   hex nipple

13. Swaged nipple:
concentric swage nipple   eccentric swage nipple

14. Flange:
Orifice flange   lap joint flange   threaded flange   socket weld flange   weld neck flange   blind flange   slip on flange   long weld neck flange   plate flange   large diameter flange   spectacle blind   square flange   

15. Outolet:
weldolet   socketolet   threadolet  laterolet  coupolet  elolet   nipoflange   nipolet

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