Types and Production Standards of Flanges

A flange, also known as a flange disc or collar, is a component used to connect pipes to one another at pipe ends.

A flange connection or flange joint is a detachable connection consisting of flanges, gaskets, and bolts combined as a set of sealing structure.

• Piping flange: flange used in piping systems
• Equipment flange: inlet/outlet flange for equipment

Flanges have bolt holes; bolts clamp two flanges together, and gaskets seal between them. Flanges are classified into:

• Threaded flanges (screwed)
• Welded flanges
• Lap-joint flanges

Flanges are always used in pairs.Threaded flanges are used for low-pressure pipelines; welded flanges are used for pressures above 4 bar.A gasket is placed between two flanges, which are then fastened with bolts.Flanges of different pressures have different thicknesses and use different bolts.
When pumps, valves, and other equipment connect to pipes, their connecting parts are also flanged, which is also called a flange connection.
Generally, any connecting part that uses bolts around two flat surfaces to achieve sealing is called a flange, such as those in ventilation ducts. Such parts can be called flange-type parts.However, a flange connection is only part of equipment (e.g., pump-flange connection), so the pump itself is not a flange-type part. Small components like valves may be referred to as flange-type parts.

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Standard Systems

1. DIN Standard

1. Pressure ratings: PN6, PN10, PN16, PN25, PN40, PN64, PN100, PN160, PN250
2. Sealing faces:

• Raised Face: DIN 2526 C
• Tongue and Groove: acc. DIN 2512 N

2. ANSI Standard

1. Pressure ratings: Class 150, 300, 600, 900, 1500
2. Sealing face: ANSI B16.5 RF flanges (Raised Face)

3. JIS Standard (less common)

Pressure ratings: 10K, 20K

API 6A / 6B Standard

Pressures: 3000 psi, 5000 psi

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Types of Flanges

Reducing Flange

• Name: Reducing Flange
• Specifications: DN15–DN300
• Standards: Manufactured in accordance with national standards
• Materials: 304, 316, 316L, 0Cr18Ni9, 321, 202, etc.
• Nominal pressure schedule: Sch5s, Sch10s, Sch20s, Sch30s, Sch40s, etc.
• Production process: integral forging, forging and stamping
• Machining: CNC lathe, conventional lathe, argon arc welding
• Features: corrosion resistance, acid & alkali resistance, long service life, smooth surface, high temperature resistance, good appearance, strong texture
• Packing: wooden case or other
• Color: metallic silver
• Price: negotiable
• Connection: bolt and nut
• Applications: water conservancy, electric power, power stations, pipe fittings, general industry, pressure vessels, etc.

Stainless Steel Flange

• Size: 1/2″ ~ 240″ (DN10 ~ DN6000)
• Pressure ratings: 0.6 MPa ~ 32 MPa, 150Lb ~ 2500Lb, PN0.25 ~ PN42.0
• Materials: 20#, 304, 304L, 321, 316, 316L, 310S, etc.

Common Standards:

• GB (Chinese): GB/T9112–2000, GB9113.1–2000 ~ GB9123.4–2000
• ANSI (American): ANSI B16.5 Class 150, 300, 600, 900, 1500 (WN, SO, BL, TH, LJ, SW)
• JIS (Japanese): 5K, 10K, 16K, 20K (PL, SO, BL, WN, TH, SW)
• DIN (German): DIN2573, 2572, 2631, 2576, 2632, 2633, 2543, 2634, 2545 (PL, SO, WN, BL, TH)
• HG (Chemical): HG20592–97, HG20615–97 series
• JB (Mechanical): JB/T79–94, JB/T74–94, JB81–59 ~ JB86–59
• Pressure Vessel: JB4700–2000 ~ JB4707–2000, JB1157–82 ~ JB1160–82

Applications:

Boilers & pressure vessels, petroleum, chemical, shipbuilding, pharmaceutical, metallurgy, machinery, food industry, etc.