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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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flat slip on flange
flat slip on flange
Petrochemical pipeline system preferred connector flat slip on flange, directly supplied by Chinese factory Longan, with customization services to meet special size requirements. The innovative double-weld structure reduces installation difficulty, and the built-in titanium alloy reinforcement ring achieves a yield strength of 1,250MPa. API 6A PSL 3G certification guarantees quality safety. One piece minimum order, fast delivery, serving global customers.
steel flat flanges
steel flat flanges
Engineers trust the high-performance pipe connector steel flat flanges from Chinese manufacturer Longan. Factory direct sales significantly reduce procurement costs and support small-batch custom trial orders. The product adopts a bionic honeycomb structure, achieving a burst pressure of 42MPa at DN300, which is 280% higher than the national standard. It has passed the authoritative API 6A PSL 3G certification and is suitable for ultra-high pressure scenarios such as shale gas fracturing pumps and deep-sea drilling platforms.
class 300 socket weld flange
class 300 socket weld flange
As a trusted China manufacturer, factory, and supplier, Longan delivers class 300 socket weld flange solutions with stable quality and precision engineering for demanding industrial pipelines. Designed for high-pressure and corrosive environments, the product offers reliable sealing performance, vibration resistance, and long-term operational stability across oil & gas, LNG, power generation, and semiconductor systems.
Female Threaded Flange
Female Threaded Flange
Female Threaded Flange China manufacturer offers easy-install threaded flange supply and export for water pipelines, compressed air systems, fire protection networks, and light industrial piping. Designed for direct connection with externally threaded steel pipes, this flange supports fast on-site assembly without welding, making it suitable for hazardous areas where open flame operations are restricted.
class 150 socket weld flange
class 150 socket weld flange
Class 150 socket weld flange China manufacturer Longan delivers 28J/mm heat input, 6MPa assembly stress, ≤10⁻¹¹ helium leakage. Factory-direct quality with ASTM G28 A zero failure. Nano-sealing, self-cleaning surface. For oil/gas, semiconductor fabs, fusion reactors. ISO/CE certified.
flat face flange
flat face flange
Longan China manufacturer flat face flange is a standard connection component used in industrial pipeline systems, mainly for the connection and sealing between pipelines, valves and related equipment. The product is widely used in oil and gas transmission, petrochemical processing, power engineering and marine engineering industries, and is suitable for basic structural connection requirements of various industrial pipeline systems.
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