High-strength And High-pressure Piping Solution
Welding neck flanges provide high-strength, high-pressure piping connections with excellent corrosion resistance, ideal for oil, gas, and power systems.
High-strength And High-pressure Piping Solution
Welding neck flanges provide high-strength, high-pressure piping connections with excellent corrosion resistance, ideal for oil, gas, and power systems.
Standard design with internal threads. Commonly used for low-pressure pipelines and where welding is not feasible.
Features internal threads that allow male-threaded pipes or fittings to be screwed in. Ensures a secure and leak-tight connection.
Comes with external threads that fit into female-threaded flanges or fittings. Suitable for specialized piping systems.
Welding Neck Flange features a long tapered neck welded to the pipe, providing exceptional strength and durability. Compliant with ASME B16.5, it uses carbon steel, stainless steel, and alloys. As of August 19, 2025, 11:17 PM PDT, it’s a leading choice for critical systems.
The High-Pressure Flange has a tapered hub that reduces stress concentration, offering pressure ratings up to 2500 PSI for Class 1500. Available in sizes from 1/2” to 48”, it suits high-pressure and high-temperature applications up to 600°C.
Welding Neck Flange undergoes radiographic and ultrasonic testing for integrity. Coated with galvanizing or FBE, it resists corrosion and is ideal for oil and gas and power generation as of August 2025, ensuring long-term reliability.
Compared to slip-on flanges, Welding Neck Flange offers superior strength and fatigue resistance for extreme conditions. Proper butt welding is essential, with a service life of 25–50 years.
Welding Neck Flange addresses challenges like stress corrosion and pressure loss in industrial piping, delivering a robust solution for oil, gas, and power systems as of August 19, 2025.
| Class | Flat Face (FF) | Raised Face (RF) | Ring Type Joint (RTJ) |
|---|---|---|---|
| ANSI 150 | WN Flange ANSI 150 FF (in) | WN Flange ANSI 150 RF (in) | WN Flange ANSI 150 RTJ (in) |
| ANSI 300 | WN Flange ANSI 300 FF (in) | WN Flange ANSI 300 RF (in) | WN Flange ANSI 300 RTJ (in) |
| ANSI 400 | WN Flange ANSI 400 FF (in) | WN Flange ANSI 400 RF (in) | WN Flange ANSI 400 RTJ (in) |
| ANSI 600 | WN Flange ANSI 600 FF (in) | WN Flange ANSI 600 RF (in) | WN Flange ANSI 600 RTJ (in) |
| ANSI 900 | WN Flange ANSI 900 FF (in) | WN Flange ANSI 900 RF (in) | WN Flange ANSI 900 RTJ (in) |
| ANSI 1500 | WN Flange ANSI 1500 FF (in) | WN Flange ANSI 1500 RF (in) | WN Flange ANSI 1500 RTJ (in) |
| ANSI 2500 | WN Flange ANSI 2500 FF (in) | WN Flange ANSI 2500 RF (in) | WN Flange ANSI 2500 RTJ (in) |
Note: The datasheets shown adhere to ASME B16.5, which covers flange dimensions from ½” to 24”. For sizes larger than 24”, please visit our flange datasheets page.
Weld neck flanges and long weld neck flanges (LWN) serve different purposes in piping systems. While they share some similarities, their differences in design and applications make each unique.
Design: Short, tapered hub smoothly transitions from flange to pipe.
Purpose: Provides strength and distributes stress evenly; suitable for high-pressure systems.
Applications: Widely used in pipelines carrying high-pressure fluids or gases.
Recognition: Identified by their short conical hub that connects pipe and flange.
Design: Extended neck acts as continuation of the pipe, longer than standard weld neck flange.
Purpose: Provides reinforcement, facilitates nozzle placement or equipment connections.
Applications: Common in pressure vessels, columns, heat exchangers, and high-temp systems.
Recognition: Easily identified by elongated neck; available in normal or heavy-duty versions.
| Feature | Weld Neck Flange | Long Weld Neck Flange |
|---|---|---|
| Neck Length | Short, tapered hub | Extended neck, elongated design |
| Primary Use | High-pressure pipelines | Pressure vessels, columns, heat exchangers |
| Strength & Stress | Even stress distribution, robust | Additional reinforcement, nozzle placement |
| Variants | Standard & reducing type | Normal thickness & heavy-duty LWN |
Standard LWN design with a uniform barrel thickness. Commonly used in general-purpose pressure vessel and column connections.
Designed with thicker barrel walls for higher pressure or heavy-duty applications. Provides additional strength and durability in extreme service conditions.
| Type | Design | Application |
|---|---|---|
| Equal Barrel (E) | Uniform barrel thickness | Standard vessels, columns, general duty |
| Heavy Barrel (HB) | Thicker barrel walls | High-pressure or heavy-duty service |
Threaded flanges are threaded in the bore which match an external thread on the pipe. Threaded flanges are used with pipes that have external threads. The benefit of these flanges is that it can be attached without welding.
Explore Threaded Flange with targeted long-tail keywords for specifications, applications, and installation solutions as of August 19, 2025.
Note: Threaded Flange meets ASME and DIN standards, ensuring reliable performance. Contact suppliers for specs.
Special Flanges
Additionally, the flanges can be modified to form other types, depending on application and functions.
These unique designs are made to incorporate specific needs and applications, like reducing flanges to answer to size and orifice flanges to incorporate orifice mounting.
The most common type, featuring a raised sealing surface that concentrates the bolting force on a smaller area.
Has a flat sealing surface, commonly used with cast iron flanges and for low-pressure applications.
Features a groove for metal ring gaskets (oval or octagonal), providing metal-to-metal sealing.
Features matching tongue and groove surfaces, providing self-alignment and confined gasket area.
Flange faces have to be smooth enough to ensure a tight, leak-free seal for bolted flanges.
| Flange Face Type | Flange Face Type | Flange Face Type |
|---|---|---|
| Type A: flat face | Type D: groove face | Type G: O Ring recess |
| Type B: raised face | Type E: spigot | Type H: O Ring groove |
| Type C: tongue face | Type F: recess |
| ASME B16.5 | Pipe Flanges NPS 1/2 - 24 |
| ASTM A105 | Forged Carbon Steel |
| ASTM A350 LF2 | Low-Temperature Service |
| ASTM A182 | High-Temperature Service |
| ASTM A694 | High-Pressure Transmission |
| DIN EN 1092-1 | European Standard PN 2.5-400 |
Most commonly used, forged with machined surfaces
Corrosion resistant, grades 304, 316, etc.
High-temperature and high-pressure applications
Cast iron, aluminum, brass, bronze, plastic
| Material Category | Fittings (ASTM Grade) | Flanges (ASTM Grade) | Valves (ASTM Grade) | Bolts & Nuts (ASTM Grade) |
|---|---|---|---|---|
| Carbon Steel | A234 Gr WPA | A105 | A216 Gr WCB | A193 Gr B7 A194 Gr 2H |
| A234 Gr WPB | A105 | A216 Gr WCB | ||
| A234 Gr WPC | A105 | A216 Gr WCB | ||
| Carbon Steel
Alloy (High-Temperature) |
A234 Gr WP1 | A182 Gr F1 | A217 Gr WC1 | A193 Gr B7 A194 Gr 2H |
| A234 Gr WP11 | A182 Gr F11 | A217 Gr WC6 | ||
| A234 Gr WP12 | A182 Gr F12 | A217 Gr WC6 | ||
| A234 Gr WP22 | A182 Gr F22 | A217 Gr WC9 | ||
| A234 Gr WP5 | A182 Gr F5 | A217 Gr C5 | ||
| A234 Gr WP9 | A182 Gr F9 | A217 Gr C12 | ||
| Carbon Steel
Alloy (Low-Temperature) |
A420 Gr WPL6 | A350 Gr LF2 | A352 Gr LCB | A320 Gr L7 A194 Gr 7 |
| A420 Gr WPL3 | A350 Gr LF3 | A352 Gr LC3 | ||
| Austenitic Stainless Steel | A403 Gr WP304 | A182 Gr F304 | A182 Gr F304 | A193 Gr B8 A194 Gr 8 |
| A403 Gr WP316 | A182 Gr F316 | A182 Gr F316 | ||
| A403 Gr WP321 | A182 Gr F321 | A182 Gr F321 | ||
| A403 Gr WP347 | A182 Gr F347 | A182 Gr F347 |
ASTM standards define the specific manufacturing process of the material and determine the exact chemical composition of pipes, fittings and flanges, through percentages of the permitted quantities of carbon, magnesium, nickel, etc., and are indicated by "Grade".
The usual materials of flanges include stainless steel, carbon steel, aluminum and plastic. The choice of the material largely depends on the purpose of the flange. For example, stainless steel is more durable and is necessary for heavy use. On the other hand, plastic is more feasible for use in the home because of its reasonable price and easy installation. The materials used for flanges are under the designation of the American Society of Mechanical Engineers.
The most common materials for pipe flanges (forged grades) are: ASTM A105 (carbon steel high temperature to match A53/A106/API 5L pipes), A350 Grades LF1/2/3 (carbon steel low temperature to match A333 pipes), A694 Grades F42 to F80 (high yield carbon steel to match API 5L pipe grades), ASTM A182 Grades F5 to F91 (alloy steel flanges to match A335 pipes), A182 Grade F304/316 (stainless steel flanges to match A312 SS pipes), A182 Gr. F44/F51/F53/F55 (duplex and super duplex to match A790/A928 pipes) and various nickel alloy grades (Inconel, Incoloy, Hastelloy, Monel).
The material qualities for these flanges are defined in the ASTM standards.
Metal flanges are classified from 150 to 2500 # rating for different pressure applications.
Incoloy 825 Flange
Industries Using
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