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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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Convex Flange
Convex Flange
Does your piping system leak after experiencing hot and cold cycles? Unplanned downtime and maintenance make costs out of control? Frequent re-tightening of bolts consumes a lot of man-hours? The failure of traditional flanges to seal under dynamic conditions is a common but expensive pain point in industrial processes. The Convex Flange produced by Longan perfectly solves this problem. It has multiple advantages: 1. It can withstand high temperature and high pressure 2. It is simple and convenient to install, and the efficiency is significantly improved 3. The sealing adaptability is very strong 4. The product is lightweight and the material utilization efficiency is high
Long Neck Flange
Long Neck Flange
Longan is a professional manufacturer of Long Neck Flanges. We will provide you with thoughtful after-sales service and prompt delivery. Long neck weld flange is a weld neck flange with an extended neck, which is used in high pressure and high temperature environments. This unique design can be used as an extension of the boring hole to provide reinforced connections in harsh environments. The products are mostly used in industries such as oil, gas and petrochemicals.
304 Alloy Steel Forged Butt Welding Flange
304 Alloy Steel Forged Butt Welding Flange
You can rest assured to buy Long’an 304 Alloy Steel Forged Butt Welding Flange from our factory.The manufacturing process of this flange includes the selection of high-quality billets, heating, forming, forging and cooling in the forging process. Normalizing, annealing or quenching + tempering treatment is carried out to optimize the material properties. Surface treatment options include galvanizing, hot-dip galvanizing, painting, anti-rust oil, etc.
304 Stainless Steel Flange
304 Stainless Steel Flange
304 stainless steel flanges have a super cost-effectiveness and are the choice of most general industrial pipelines.
304 stainless steel flanges have various types, including blind plates, butt-welded necks, loose sleeves, threaded types, etc., and the chromium-nickel content is ≥18/8% verified by XRF. The service life in ordinary environments (pH>4.5) is more than 10 years, which is 400% higher than carbon steel. However, the cost is 35% lower than that of 316 flanges.
304 Welding Flange
304 Welding Flange
304 welding flange complies with ASME B16.5 standard, and the pressure covers Class 150~900. After 500 hours of salt spray test, the service life of carbon steel flange is increased by 400%, and the cost is 30~35% lower than that of 316 flange.
304 Neck Butt Welding Flange
304 Neck Butt Welding Flange
304 Neck Butt Welding Flange is suitable for non-extreme corrosion scenarios such as water treatment, HVAC, and food equipment. The product provides corrosion resistance in oxidizing environments through 18% chromium + 8% nickel components, complies with ASME B16.5 standards, and covers pressures from Class 150 to 900. Verified by a 500-hour salt spray test, the life of carbon steel flanges is increased by 400%, and the cost is 30 to 35% lower than 316 stainless steel. ASTM A182 material certification and dimensional accuracy reports are also provided.
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