High-Quality ASME B16.5 Weld Neck Flange
Material: ASTM A105N Carbon Steel | Forged Strength
The Weld Neck Flange (WNF) is the premium choice for high-pressure, high-temperature, and fluctuating stress environments. Characterized by a long tapered hub that is butt-welded to the pipe, this design ensures a smooth transition of stress and minimizes turbulence within the pipeline.
1. Material Specification: The "N" Advantage (ASTM A105N)
Our flanges are manufactured from ASTM A105N, where the "N" stands for Normalized heat treatment.
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Refined Grain Structure: Normalizing involves heating the steel to a specific temperature and cooling it in still air, which uniformizes the grain structure.
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Enhanced Toughness: Compared to standard A105, A105N provides superior impact strength and ductility, especially in lower-temperature service.
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Extended Lifespan: Better resistance to fatigue and internal pressure surges.
2. Engineering Excellence
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Structural Integrity: The tapered hub moves the stress concentration away from the flange base to the pipe itself, providing vital reinforcement.
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Butt-Weld Connection: Allows for easy radiography (X-ray) inspection of the weld seam, ensuring 100% safety compliance for critical applications.
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Bore Matching: We precision-machine the flange bore to match your specific pipe schedule (e.g., Sch 40, Sch 80, Sch XS, Sch 160), preventing internal flow restrictions.
3. Technical Parameters
| Feature | Details |
| Standard | ASME B16.5 (Pipe Flanges and Flanged Fittings) |
| Size Range | 1/2" to 24" (Larger sizes available per ASME B16.47) |
| Pressure Class | Class 150, 300, 400, 600, 900, 1500, 2500 |
| Facing | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ) |
| Surface Coating | Anti-rust oil, Black Paint, Yellow Paint, or Hot-Dip Galvanized |
4. Typical Applications
Due to its robust design, the A105N Weld Neck flange is the industry standard for:
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Oil & Gas Refineries: High-pressure crude oil and gas transmission lines.
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Steam Systems: High-temperature boiler piping and power plant infrastructure.
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Chemical Processing: Handling non-corrosive fluids at elevated pressures.
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Critical Utilities: Main water and gas trunklines requiring maximum safety.
5. Why Choose Our Forged Flanges?
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Strict Forging Ratio: We ensure a high forging ratio to eliminate internal porosity and defects common in cast products.
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CNC Precision: Serrated spiral finishes (125-250 AARH) on the flange face ensure optimal gasket "grip" and a leak-proof seal.
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Comprehensive Certification: Every shipment is accompanied by an EN 10204 3.1 MTC, detailing chemical analysis, tensile strength, hardness, and impact test results.
Do you need to match these flanges with specific pipes?
I can provide you with a Dimensional Chart for Class 150 vs. Class 300 to help you confirm the bolt hole patterns for your project. Would you like me to generate that for you?
