Flange Types And Engineering Selection Guide

As the core connecting component of pipeline systems, the selection of flanges directly impacts the system's sealing performance and service life. This article systematically reviews the technical characteristics of mainstream flange types, and based on Leadtek's professional experience in the stainless steel flange manufacturing field, provides decision-making guidelines for flange selection in industrial scenarios.

 

 

1. Flange Classification System and Technological Evolution

According to the ASME B16.5/EN 1092 standard, industrial flanges can be divided into six main technical categories based on their structure:

Type	Connection Method	Pressure Rating (PN/Class)	Typical Application Scenarios
Weld Neck Flange	Butt Welding	PN16-Class300	High-temperature and high-pressure steam pipelines
Slip-On Flange	Double Angle Welding	PN10-Class150	Low-pressure circulating water systems
Socket Weld Flange	Socket Welding	PN40-Class600	Instrument pressure tapping connections
Threaded Flange	G/NPT Threaded Connection	PN6-Class150	Compressed air pipe networks
Blind Flange	Bolt Seal	PN100-Class2500	Pressure vessel maintenance openings
Loose Flange	Loose Ring Compression	PN25-Class300	Pipeline thermal displacement compensation

Note: Special scenarios may require the use of rotating flanges (maximum deflection angle of 15°) or reducing flanges (reduction ratio ≤ 3:1).

 

2. In-depth Analysis of Key Flange Types

Weld Neck Flange

● Structural Features: 60° tapered neck welded to the pipeline with full penetration to achieve stress gradient distribution (Finite Element Analysis shows a 37% reduction in stress concentration factor).

● Technical Advantages:

Ensures weld integrity through 100% radiographic inspection (RT).

Suitable for cyclic loading conditions (fatigue life > 10^6 cycles).

Compatible with 316L stainless steel material, resistant to CL- ion corrosion (concentration ≤ 20000ppm).

Slip-On Flange

● Double Angle Welding Process: Inner welds bear 80% of the main stress, and outer welds provide airtight sealing.

● Economic Solution: Reduces steel usage by 25% compared to weld neck flanges, improving installation efficiency by 40%.

High Pressure Blind Flange

● Sealing Design: Spiral groove sealing face (RMS ≤ 3.2μm) combined with metal spiral wound gasket (graphite/316L stainless steel).

● Mechanical Verification: Verified by ANSYS simulation, with deformation less than 0.2mm/m at Class1500 rating.

 

Leadtek Brand Value Extension

With 30 years of experience in the stainless steel flanges, valves, and pipe fittings industry, we not only provide a wide range of products but also use digital selection and modular design systems to shorten the lead time for non-standard flange customization, helping customers build safe and efficient pipeline networks.