ASTM A182 F316/316L Stainless Steel Flange Weld Neck / WNRF Flange in Piping System
ASTM A182 F316/316L Stainless Steel Flange ASME B16.5 Forged Weld Neck / WNRF Flange
The ASTM A182 F316/316L WNRF flange offers a robust, weldable, and corrosion-resistant joint suitable for critical industrial piping systems. Its dual certification, high-strength hub design, and compliance with ASME B16.5/B16.47 make it a preferred choice for engineers requiring reliability in aggressive or high-pressure environments.
Basic Function of Steel Weld Neck Flange
A flange is a mechanical connector that joins two sections of pipe, valves or equipment while allowing disassembly. The WN Flange works by:
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Permanent attachment to the pipe via a full-penetration butt weld.
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Removable bolted connection to the mating flange (another WNRF, a blind flange, or equipment flange).
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Sealing through a compressed gasket between the two flange faces.
| Scenario | Recommendation |
|---|---|
| Project in Europe, Asia, or spec calls for PN | Use EN 1092-1 |
| Project in North America, or spec calls for Class | Use ASME B16.5 / B16.47 |
| Connecting to existing flanges | Must match the standard – do not mix EN and ASME directly |
| International oil & gas (offshore) | Often ASME, but some European operators accept EN with PN/Class conversion |
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* Never directly bolt an EN 1092-1 flange to an ASME B16.5 flange. Bolt circle diameters, hole sizes, and facing dimensions are different. Use a proper adapter flange or a custom-made transition piece designed to both standards. |
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Equivalent Materials of ASTM A182 F316L Stainless Steel WNRF Flange
| STANDARD | WERKSTOFF NR. | UNS | JIS | BS | GOST | AFNOR | EN |
| SS 316L | 1.4404 | S31603 | SUS 316L | 316S11 | 03Ch17N14M3 | Z3CND17‐11‐02 | X2CrNiMo17-12-2 |
Chemical Composition % of ASTM A182 F316L Stainless Steel WNRF Flange
| SS | UNS | C | MN | P | S | SI | CR | NI | MO | NB | TI |
| F316L | S31603 | 0.030 | 2.00 | 0.045 | 0.030 | 1.00 | 16.0-18.0 | 10.0-15.0 | 2.0-3.0 | --- | --- |
How it Resists Leakage
Leakage occurs when internal pressure pushes the gasket outward, reducing contact stress. The WNRF design counters this through:
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High bolt stiffness (short bolt span due to compact flange geometry).
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Strong hub prevents flange rotation (bending apart under pressure).
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Controlled gasket compression – ASME B16.5 defines allowable bolt loads.
Application
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Chemical & Petrochemical processing (handling corrosive fluids)
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Oil & Gas (onshore/offshore, refineries)
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Power generation (including nuclear auxiliary systems)
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Marine & shipbuilding (seawater systems)
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Pharmaceutical & food processing (hygienic and corrosion-resistant needs)
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LNG and cryogenic services (good toughness at low temperatures)
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