Stainless Steel Flanges and Fittings Guide

The following is a detailed guide to stainless steel flanges and accessories, covering common types, standards, selection points and application scenarios, to help you quickly understand the key components of stainless steel piping systems.

1. Overview of stainless steel flanges

Stainless steel flanges are used to connect pipes, valves, and equipment. They have the characteristics of corrosion resistance, high strength, and high temperature resistance. Common materials are 304, 316, and 316L.

1. Common flange types

Type Features Application scenarios

Slip-on flange (SO) The welding end is flat, easy to install, low cost, but the pressure is low. Low-pressure and normal temperature system (water, air)

Butt welding flange (WN) Neck butt welding, high strength, high pressure and high temperature resistance. Petroleum, chemical, high-temperature steam pipelines

Lap Joint Flange (Lap Joint) The flange ring can be rotated and welded with a short pipe for easy alignment. Systems that require frequent disassembly (such as cleaning pipelines)

Threaded flange (Threaded) Internal thread connection, no welding required. Small-diameter low-pressure pipeline (≤DN50)

Blind flange (Blind) Close the end of the pipeline for isolation or future expansion. System testing, maintenance isolation

2. Flange standards

International standards:

ANSI/ASME B16.5 (American standard, pressure level: 150#~2500#)

EN 1092-1 (European standard, PN6~PN100)

JIS B2220 (Japanese standard)

Domestic standards:

GB/T 9119 (slip-on flange)

HG/T 20592 (Ministry of Chemical Industry standard)

3. Flange sealing surface type

FF (Flat Face): flat surface, used for low pressure.

RF (Raised Face): convex surface, commonly used for medium and high pressure.

RTJ (Ring Joint): ring groove surface, high pressure and high temperature (such as petrochemical industry).

2. Stainless steel pipe fittings

Stainless steel fittings are used to change flow direction, branch, reduce diameter or connect. Common types include:

1. Common fitting types

Type Function Example

Elbow Change pipe direction (90°, 45°) Long radius (LR), short radius (SR)

Tee Split or merge (equal diameter/reducing diameter) Equal diameter tee, reducing tee

Reducer Connect pipes of different diameters Concentric reducer, eccentric reducer

Cap Close the end of the pipe Welded, threaded

Union Quick disassembly connection Union with thread or flange

2. Fitting standards

ANSI/ASME B16.9 (butt welding fittings)

ANSI/ASME B16.11 (socket welding/threaded fittings)

DIN 2605 (German standard elbow)

3. Key factors for selection

Material selection:

304: general purpose, weak corrosion resistance (food, water treatment).

316/316L: Contains molybdenum, resistant to chloride ion corrosion (seawater, chemical industry).

Pressure level: Select according to the system working pressure (such as PN16, ANSI 150#).

Media compatibility: Acidic/alkaline media need to consider the corrosion resistance of the material.

Temperature range: Butt welding flange or thickened design is required for high temperature environment.

IV. Installation precautions

Sealing gasket matching: Select gasket according to the medium (such as PTFE, metal spiral wound gasket).

Bolt tightening: Cross-symmetrical tightening to avoid leakage.

Welding requirements: 316L requires low-carbon welding process (to avoid intergranular corrosion).

V. Application industry

Food/Pharmaceutical: Sanitary flange (polished, FDA compliant).

Chemical/Energy: High-pressure flange + anti-corrosion coating.

Ship/Seawater: 316L flange is resistant to salt spray corrosion.

If more specific parameters (such as dimension table, weight calculation) or special application scenarios (such as ultra-high vacuum) are required, further explanation can be provided!

Cangzhou Aosendik Pipe Fittings Manufacturing Co., Ltd. is a large manufacturer specializing in the production of elbows, tees, reducers, elbows and caps. We can implement ASTM, ANSI, JIS, DIN, GB and other standards, basically covering all types of steel.

If you have any purchasing needs or questions, 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