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Flange

Understanding the Role of Flange in Industrial Applications: A Comprehensive Guide

As an important part of piping system, flanges play a vital role in connecting pipes, valves, pumps and other equipment. The products are used in oil and gas, chemical or water treatment plants and these places.

What is a Flange?


Flanges are flanges or ridges used to connect pipes, fittings or machinery. Flanges are bolted or welded to form a strong connection for easy assembly, disassembly and inspection. Flanges come in a variety of shapes and sizes to withstand different pressures, temperatures and environmental conditions. By standardizing connections, flanges promote interoperability between systems, thereby reducing downtime and maintenance costs.


Key Parameters of Flanges

Size: refers to the nominal pipe size (NPS) or diameter, which must be matched to the connected components. 

Pressure Rating: indicates the maximum pressure that the flange can withstand, usually classified according to standards such as ANSI/ASME (e.g. Class 150, Class 300, Class 600). 

Materials: Commonly used materials include carbon steel, stainless steel, alloy steel, and non-ferrous metals such as brass or copper, which are selected for their corrosion resistance and strength. 

Face types: These include flat faces (FF), raised faces (RF) and ring joints (RTJ), which affect sealing efficiency. 

Bolt hole layout: the number and diameter of bolt holes, which are critical for alignment and tightening. 

Standards: Compliance with international standards such as ANSI, ASME, DIN or JIS ensures compatibility and safety.

Detailed Product Parameters Table

Parameter Description Common Values
Nominal Size Diameter of the pipe connection 1/2" to 24" (or larger)
Pressure Class Maximum pressure rating Class 150, 300, 600, 900, 1500, 2500
Material Grade Type of material used A105 (Carbon Steel), SS304 (Stainless Steel), Alloy 20
Face Type Surface design for gasket sealing Raised Face (RF), Flat Face (FF), Ring-Type Joint (RTJ)
Bolt Circle Diameter Diameter of the bolt hole circle Varies by size and class (e.g., 3.5" for 2" Class 150)
Standards Governing specifications ANSI/ASME B16.5, DIN 2527, JIS B2220

Types of Flanges

Flanges are categorized based on their design and application. Here are the most common types:

  • Weld Neck Flange: Features a long tapered hub for high-stress applications, ideal for high-pressure systems.
  • Slip-On Flange: Easy to install by sliding over the pipe and welding, suitable for low-pressure environments.
  • Blind Flange: Used to seal the end of a piping system, allowing for future expansion or inspection.
  • Socket Weld Flange: Provides smooth flow and high strength, commonly used in small-bore piping.
  • Threaded Flange: Screwed onto pipes without welding, ideal for non-hazardous or low-pressure systems.
  • Lap Joint Flange: Pairs with a stub end for easy alignment, perfect for systems requiring frequent disassembly.
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Long Weld Neck Flanges
Long Weld Neck Flanges
Long Weld Neck Flanges have significantly improved corrosion resistance in chloride environments through ≥2.1% molybdenum content, comply with ASME B16.5 standards, and cover pressures from Class 150 to 2500. Compared with 304 flanges, the salt spray test has been verified for 1,000 hours, and the service life can be increased by 300%, reducing leakage risks and maintenance costs. Suitable for harsh scenarios such as seawater desalination, chemical industry, and pharmaceuticals, ASTM A182 material certification (MTR) and third-party certification (NACE/PED) can be provided
316 Neck Butt Welding Flange
316 Neck Butt Welding Flange
High-quality 316 Neck Butt Welding Flanges can provide superior corrosion resistance in chloride environments. Longan produces a full range of 316 flanges with pressure ratings from 150 to 2500 and sizes from 1/2 inch to 24 inches. We are MTR certified, have sufficient supply and fast delivery. Click here to request a quote now!
High Pressure Flange
High Pressure Flange
You can rest assured to buy High Pressure Flange from our factory. Longan provides engineering-grade flange solutions to solve high-pressure seal failures, covering stainless steel/carbon steel/alloy steel, etc., meeting DINA, SME, API, standards, and providing pressure calculator + 72h emergency replacement service, as well as free system diagnosis services. Come and contact us.
Steel High Pressure Flange
Steel High Pressure Flange
Longan Flange is a Steel High Pressure Flange manufacturer with ISO 9001 certification, providing customized PN100~PN800 pressure levels, ASTM A105/A182 F316L materials, 30-year corrosion resistance guarantee, and 72-hour global delivery. Free technical consultation and other services to help you solve better sealing services.
Carbon Steel High Pressure Flange
Carbon Steel High Pressure Flange
The core of Carbon Steel High Pressure Flange is as follows: Life cycle: 25 years + (corrosion rate <0.1mm/year, C3 grade anti-corrosion environment), required pressure limit, up to PN100 (10MPa) The maximum burst pressure can be ≥85MPa (third-party SGS actual measurement), sealing leakage rate: <10⁻⁶ mbar·L/s (ISO 5208 A grade standard) Temperature adaptability: -29℃~425℃ (low temperature impact toughness ≥27J)
Flat Welding Raised Face Flange
Flat Welding Raised Face Flange
Flat Welding Raised Face Flanges are widely used in oil and gas transportation, pharmaceutical clean systems, and power station valve groups. The flanges produced by Longan are known for their reputation of "1 flange = 3 certifications". Material traceability, pressure integrity, and product digital management are our advantages. You can feel free to contact us!
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