Description
Weld Neck Steel Flanges (also widely classified as Hubbed Butt Welding Flanges or WN Flanges) are heavy-duty forged pipe connectors engineered with a tapered long hub that provides smooth transition and full-penetration butt welding to pipes. Designed specifically for critical high-pressure, high-temperature, or sub-zero piping environments, these hubbed butt welding flanges transfer stress smoothly from the flange to the pipe wall, minimizing stress concentrations at the base of the flange.
Precision-machined strictly to international standard tolerances, our weld neck flanges connect flawlessly alongside our industrial butterfly valves and form leak-free, high-integrity piping loops across our industrial flanges manufacturing lines.
Technical Specifications
| Technical Parameter | Specification Details |
|---|---|
| Nominal Size Range | 1/2" to 24" (DN15 to DN600) per ASME B16.5; Up to 60" (DN1500) per ASME B16.47 |
| Pressure Class Ratings | Class 150, Class 300, Class 600, Class 900, Class 1500, Class 2500; PN10 to PN400 |
| Material Grade Options | Carbon Steel (ASTM A105 / A350 LF2), High-Yield Steel (API 5L F42-F70), Stainless Steel (304/304L, 316/316L, Duplex 2205) |
| Flange Facing Options | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Tongue & Groove (T&G) |
| Manufacturing Standards | ASME B16.5, ASME B16.47, EN 1092-1 Type 11 (Weld-neck), DIN 2631 - DIN 2638, JIS B2220 |
| Quality Control & Testing | 100% Ultrasonic Testing (UT), Radiographic Testing (RT) options, PMI Material Check, EN 10204 3.1 MTR |
Key Features & Structural Mechanics
Deploying hubbed butt welding steel flanges provides maximum mechanical reliability in heavy-duty piping systems:
- Superior Stress Distribution: The tapered long hub gradually matches the pipe wall thickness, eliminating sharp structural transitions and reducing fatigue stress under severe bending loads.
- Full Penetration Butt Weld Connection: Radiographically inspectable circumferential butt welds ensure maximum pressure containment and 100% joint efficiency matching the pipe rating.
- Resistance to Thermal & Pressure Cycling: Ideal for systems subjected to rapid temperature fluctuations, water hammer, or cyclic mechanical vibrations.
Target Applications & Industries
Our forged weld neck flanges are widely installed across critical global infrastructure networks:
- Oil & Gas Transmission Trunklines: Cross-country gas pipelines, high-pressure crude oil headers, and offshore platform risers.
- Power Plants & High-Pressure Steam Lines: Superheated steam lines, boiler feed networks, and turbine connections.
- Chemical Processing & Petrochemical Refineries: Severe service chemical loops handling toxic, corrosive, or flammable media under high pressure.
Frequently Asked Questions (FAQ)
Q1: What is the main difference between a Weld Neck Flange and a Slip-On Flange?
A Weld Neck Flange features a long tapered hub that is butt-welded to the pipe, offering higher fatigue strength and suitability for severe high-pressure conditions. A Slip-On Flange slides over the pipe end and uses fillet welds, making it suitable for lower-pressure applications.
Q2: Why is the bore (schedule) of a weld neck flange critical during ordering?
The internal bore of a weld neck flange must match the inside diameter of the mating pipe (e.g., Sch 40, Sch 80, Sch XS) to prevent internal flow restrictions, turbulence, and erosion at the weld joint.
Q3: Does Oucang Valve provide full material traceability for high-pressure WN flanges?
Yes. All forged weld neck flanges manufactured by Oucang Valve are accompanied by EN 10204 3.1 Material Test Reports (MTR), detailing chemical heat analyses, heat treatment records, and physical tensile testing.
About the Manufacturer: Oucang Valve
Oucang Valve is an ISO-certified direct manufacturer specializing in heavy-duty forged steel pipe flanges, weld neck (hubbed butt welding) flanges, and high-performance industrial valves. Operating our own hydraulic ring forging workshops, CNC machine centers, and NDT laboratory, we provide complete engineering support and OEM production for global industrial projects.
- Core Capability: Precision forged weld neck flanges, ASME B16.5 / EN 1092-1 compliance, UT/RT non-destructive testing, and fast export delivery.
- Quality Compliance: ASME B16.5, ASME B16.47, EN 1092-1, DIN, JIS, and ISO standards.
- Factory Inquiry: Contact our engineering sales team for direct factory quotations, material test reports, and 2D/3D CAD drawings.
