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12 Kinds Of Flanges (part One)

Apr 10, 2020

     As a kind of indispensable spare part in piping design, flanges can be used in a wide range of fields, such as industrial furnace, water supply and drainage, heating and ventilation.

Materials:

        Forged steel, WCB carbon steel, stainless steel, 316L, 316, 304L, 304, 321, Cr-Mo steel, Cr-Mo-V steel, 316Ti, rubber lining, fluorine materials

Classification:

        Ring flange, welding neck flange, slip-on flange, blind flange, orifice flange, threaded flange, socket weld flange,  etc.

Standard:

        GB standards, JB standards, HG standards, ASME (U.S.), BS4504 (British), DIN (Deutsches), JIS (Japan)

12 Kinds of Flanges and Their Characteristics

Welding Plate Flange (HG/20592, GB/T9119, JB/T81)

Pro: easy obtaining, simple manufacturing, low cost, a wide range of applications

Con: It is not solid enough to be used in flammable, combustible, or high-vacuum pipe system and other highly dangerous situations.

Face type: flat face and raised face

Slip-on Flange

Pro:

1. Easy installation, 

2. Non-destructive inspection can be omitted.

Con:

1. Short neck, inadequate rigidity, bearing capacity

2. Heavy workload of welding, high consumption of welding rod

3. Unable to bear high temperature and pressure, repeated bending and temperature fluctuation

Welding Neck Flange

Face type: RF, FM, M, T, G, FF

Pro: 

1. Not easy to deform when connecting, good sealability

2. It is able to be used in situations with drastic fluctuation of temperature, pipeline with high pressure, high or cryogenic temperature. 

3. It can also be used in pipeline that transports flammable and combustible media, toxic gases, expensive media.

Con:

1. Bulky, heavy and expensive

2. Difficult installation and positioning

Integral Flange

Integral flange, also called long weld neck flange (LWN flange), is normally forged and widely used in pipeline with high pressure. 

Materials: Carbon steel, stainless steel, alloy steel, etc.

Precaution: For flammable, combustible and highly dangerous situations, choose MFM and TG face types, rather than RF.

Socket Weld Flange

It is a flange whose one side is welded with pipe and the other side is connected by screws.

Face type: RF, MFM, TG, RJ

Application: Boiler and pressure vessels, petroleum, chemical engineering, ship building, pharmacy, metallurgy, mechanical engineering,  food industries, etc. (pipeline: PN≤10.0MPa, DN≤40)

Threaded Flange

It is a non-welded flange whose inner bores are processed into pipe threads so as to connect with pipes that have treads.

Pro:

Compared to welded flange or WN flange, it has advantages such as convenient installation and maintenance, being suitable for situations where welded flange or WN flange cannot be used, a replacement of alloy steel flange, which has high rigidity, yet is hard to weld.

Con:

Threaded flanges are not recommended to be used (to prevent leaking) in situations where has drastic changes of temperature or temperature higher than 260℃ or lower than -45℃.