High Neck Flange: The Ultimate Guide to Specifications and Applications

The High Neck Flange is a specialized pipe fitting designed for high-pressure applications where standard flanges may not be sufficient. This guide provides detailed specifications, technical parameters, and answers to frequently asked questions about this essential industrial component.

Product Specifications

Key Features:

• Manufactured from high-grade carbon steel, stainless steel, or alloy materials
• Designed for pressures up to 6000 psi (413 bar)
• Available in sizes from 1/2" to 48" (DN15 to DN1200)
• Temperature range: -20°F to 1000°F (-29°C to 538°C)
• Multiple facing options: raised face, flat face, ring-type joint

Technical Data Table:

Size (inches)	OD (mm)	Thickness (mm)	Bolt Circle Diameter (mm)	Number of Bolt Holes
1/2"	89	14	60.3	4
1"	108	16	73	4
2"	152	19	102	8
4"	216	22	159	8
8"	381	29	298	12

Pressure Ratings

The High Neck Flange is available in multiple pressure class ratings to suit various industrial requirements:

• Class 150
• Class 300
• Class 600
• Class 900
• Class 1500
• Class 2500

Frequently Asked Questions

What is the main advantage of a High Neck Flange compared to standard flanges?

High Neck Flanges offer superior strength and durability for high-pressure applications. The extended neck provides additional reinforcement at the weld joint, making them ideal for critical services where standard slip-on or weld neck flanges might not provide sufficient structural integrity. Their design allows for better stress distribution and improved fatigue resistance.

How do I select the right High Neck Flange for my application?

Selection should be based on four key factors: 1) Operating pressure and temperature, 2) Pipe material and size, 3) Connection type requirements, and 4) Environmental conditions. Always consult the appropriate ASME/ANSI standards (B16.5 or B16.47) and consider factors like corrosion potential, vibration levels, and cyclic loading conditions.

Can High Neck Flanges be used in cryogenic applications?

Yes, specially designed High Neck Flanges with appropriate material selection (typically austenitic stainless steel grades) can be used in cryogenic applications down to -320°F (-196°C). These flanges must meet additional testing requirements to ensure they maintain their mechanical properties at extremely low temperatures and should be clearly marked for cryogenic service.

Installation and Maintenance

Proper installation of High Neck Flanges is critical for optimal performance:

• Ensure proper alignment before welding
• Use qualified welders following approved procedures
• Apply proper bolt tightening sequence and torque values
• Conduct regular inspections for signs of leakage or stress

Industry Standards Compliance

Our High Neck Flanges meet or exceed the following standards:

• ASME B16.5 - Pipe Flanges and Flanged Fittings
• ASME B16.47 - Large Diameter Steel Flanges
• API 6A - Specification for Wellhead and Christmas Tree Equipment
• ANSI/ASME B31.3 - Process Piping