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Flange types and standards

Feb. 11, 2026

Flange Types and Standards

Flanges, also known as flange plates or flanges, are mainly manufactured through four processes: forging, casting, cutting, and rolling. Die forging is the most commonly used method. Die forging, also known as die forging, involves placing a heated blank into a die fixed on forging equipment to form the flange.

I. Flange Classification:

Common flange types include: flat plate flanges, neck flat plate flanges, neck welding flanges, socket welding flanges, threaded flanges, loose fit flanges, and flange covers.

Common size range: 1/2” (DN15) - 24” (DN600).

European standard nominal pressure is expressed in PN, including nine grades: PN2.5, PN6, PN10, PN16, PN25, PN40, PN63, PN100, and PN160. The American Standard for Pressure Ratings (ASM) uses the CLASS designation, including six levels: CLASS 150, CLASS 300, CLASS 600, CLASS 900, CLASS 1500, and CLASS 2500.

Plate-face sliding flanges (PL): Materials are readily available, manufacturing is simple, cost-effective, and they are widely used.

Sealing face types: Flat face (FF) and raised face (RF).

Slip-on flanges with necks (SO): A type of flange that connects steel pipes, fittings, etc., to equipment or pipelines via fillet welds.

Sealing face shapes: Raised face (RF), concave face (FM), male face (M), tongue and groove face (T), groove face (G), flat face (FF).

Welded neck flanges (WN): Used for butt welding between flanges and pipelines; they feature a reasonable structure, high strength, good rigidity, and reliable sealing performance.

Sealing face types include: flat face (FF), raised face (RF), male face (M), female face (FM), tongue and groove (T), grooved face (G), and ring face (RJ).

Socket weld flange (SW): This refers to a flange where the pipe end is inserted into the flange's ring groove and connected to the outside of the flange by welding. Socket weld flanges are divided into necked and non-necked types.

Sealing face types: Raised face (RF), male face (MFM), tongue and groove face (TG), and ring face (RJ).

Threaded flange (TH): This is a non-welded flange with its inner hole machined into a pipe thread, used for connection to threaded pipes. Threaded flanges are easy to install and maintain and can be used for pipelines where welding is not permitted on site.

Loose wing flange (LAPJ): Generally divided into butt weld loose wing flanges and flush weld loose wing flanges.

Blind flange cover (BL): Also known as a blind flange or blind plate. This is a flange without a center hole, used to seal pipe plugs.

Sealing Faces: Flat Face (FF), Raised Face (RF), Male Face (MFM), Tongue and Groove Face (TG), Ring Face (RJ)

II. Flange Standards: Standards include ASEM B16.5, ASME B16.47, GB/T 9112-GB/T9124, HG 20592-HG20605, HG20615-HG20626, and SH3406.

III. Flange Materials: Commonly used materials include carbon steel, stainless steel, and alloy steel. ASTM A105; A182 F5, F11, F12, F22, F91, F304/L, 316/L, F904L; A350LF2/LF3, A694 F52, F60, F65.

Cangzhou Aosendike Pipe Fittings Manufacturing Co., Ltd. is a large-scale manufacturer specializing in elbows, tees, reducers, and pipe caps. We can manufacture according to ASTM, ANSI, JIS, DIN, GB, and other standards, basically covering all types of steel.

For any purchasing needs or inquiries, please contact us.

Mobile: 86-13668807131

Website: https://www.authenticfitting.com/

Address: Mengcun Hui Autonomous County, Cangzhou City, Hebei Province

Email: authentic013@steelpipes-fitting.com

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