Types of Pipe Flanges – Complete Classification Guide

Flanges are essential components in piping systems, allowing for easy assembly, disassembly, and maintenance. At Udhhyog, we supply all major types of pipe flanges used across industries including waterworks, oil & gas, chemicals, HVAC, and fire-fighting lines. This guide helps you understand different flange types, their functions, and classifications.

Flange Classifications

• By Connection Type: Weld Neck, Slip-On, Threaded, Socket Weld, Lap Joint
• By Purpose: Blind, Orifice, Spectacle Blind
• By Material: Mild Steel, Stainless Steel, Cast Iron
• By Standard: ASA 150, ANSI B16.5, IS 1538
• By Facing: Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ)

1. Weld Neck Flange

Weld Neck Flanges have a long tapered hub and are butt-welded to the pipe. These flanges are suitable for high-pressure, high-temperature systems due to their smooth flow transition and stress distribution.

• Standard: ASA 150 / ANSI B16.5
• Application: Refineries, boilers, petrochemicals
• Size Range: ½" to 24"

2. Slip-On Flange

Slip-On Flanges slide over the pipe and are welded from both sides. These are easier to align and install compared to weld neck flanges, making them popular in lower pressure setups.

• Cost-effective
• Moderate pressure & temperature use
• Size Range: ½" to 60"

3. Blind Flange

Blind Flanges seal the end of a piping system or pressure vessel. They do not have a bore and are ideal for pressure testing, inspection, or future pipe expansion.

• Used in valves, vessels, tanks
• Can withstand full pressure

4. Threaded Flange

Threaded Flanges are used in systems where welding is not feasible. They have internal threads that fit with externally threaded pipes, ideal for flammable or explosive media.

• Easy installation
• Best for low-pressure systems

5. Socket Weld Flange

Socket Weld Flanges have a socket for pipe insertion before fillet welding. They are good for small diameter, high-pressure pipes and ensure a smooth bore and strong joint.

6. Lap Joint Flange

Lap Joint Flanges are used with stub ends and are not welded directly to the pipe. They're ideal for systems requiring frequent dismantling and corrosion inspection.

7. Orifice Flange

Orifice Flanges come with pressure tap holes for flow measurement using orifice plates. Common in oil & gas and chemical plants for monitoring pressure drop and flow rate.

8. Spectacle Blind Flange

Spectacle Blinds are two metal discs – one open, one closed – joined with a small handle. They serve as mechanical safety devices for isolation or flow diversion in pipelines.

Materials Used in Flanges

• MS (Mild Steel): Cost-effective, commonly used in general industrial and water lines
• SS (Stainless Steel): Corrosion-resistant, used in chemical, food, and pharmaceutical lines
• CI (Cast Iron): Traditional usage, now less common in pressure applications

Applications of Different Flange Types

Why Choose Udhhyog for All Flange Types?

• All IS 1538, ASA 150 & ANSI-compliant flanges
• MS, SS, GI options available
• Bulk order discounts + unsecured credit for MSMEs
• Fast delivery and custom manufacturing available

FAQs – Types of Flanges

Q. What are the most commonly used flange types?

A. Weld Neck, Slip-On, and Blind Flanges are the most widely used.

Q. How to choose the right flange?

A. Consider pressure, temperature, pipe size, and connection type. Contact Udhhyog for expert help.

Q. Do all flange types support the same pressure?

A. No, pressure ratings vary. Weld neck and blind flanges usually support higher ratings than slip-on or threaded types.

Q. Are MS flanges cheaper than SS flanges?

A. Yes, MS flanges are generally more affordable but less corrosion-resistant than SS flanges.

? Contact Udhhyog to Buy Pipe Flanges

Get all standard flange types with IS and ANSI compliance at the best prices. Send your enquiry today or check our full flange catalogue.