Steel Weld Neck Flanges (WN Flanges) are high-performance forged/cast pipe flanges engineered for rigid connection of pipes, valves, pumps, and industrial equipment, forming leak-proof piping systems. Characterized by a long, tapered neck with a beveled hub (for butt welding to pipes), they deliver exceptional pressure-bearing capacity and structural alignment. Key characteristics, specifications, and technical details are as follows:
- Core Definition: A flange with an integrated long tapered neck and beveled welding end, designed for butt-welded connection to pipelines/equipment. The neck transfers stress evenly, ensuring stability in high-pressure/high-temperature systems.
- Structural Features:
- Forged primary construction (cast optional for low-pressure scenarios) – eliminates internal defects, enhances mechanical strength;
- Long tapered neck design – improves rigidity, reduces stress concentration at the weld joint;
- Beveled hub (30°/45° standard bevel) – ensures full penetration welding and precise alignment with pipes;
- Standardized bolt hole patterns and precision-machined sealing faces – compatible with mating flanges.
- Material Scope:
- Forged steel: Carbon steel (A105, Q235B), stainless steel (304L, 316L, duplex 2205/2507), alloy steel (A182 F11/F22/F91);
- Cast steel (low-pressure only): WCB, CF8 (compliant with ASTM, EN, JIS standards) – prioritizes corrosion resistance, high-temperature stability, and pressure-bearing capacity.
- Key Specifications:
- Size Range: DN10 – DN3600 (customizable non-standard sizes); compatible with NPS (1/2" – 144") and JIS A-series (15A – 1500A).
- Pressure Class: PN0.1 – PN420 / Class 150 – 2500 (optimized for ultra-high pressure/high-temperature systems).
- Sealing Face Types: Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ) – matched to system pressure and media requirements.
- Connection Method: Butt welding (neck to pipe) + bolted joint (flange to flange) – weld ensures permanent, leak-proof integration; bolted connection facilitates equipment maintenance.
- Core Advantages:
- Superior pressure-bearing capacity (handles up to PN420/Class 2500) and high-temperature resistance (-200℃ – 1000℃) – ideal for critical systems;
- Long neck design distributes stress evenly, preventing weld joint failure under cyclic loads;
- Precise alignment via beveled hub – reduces installation errors and improves system integrity;
- Forged structure offers excellent corrosion resistance (suitable for chemicals, seawater, acidic/alkaline fluids) and long service life;
- Permanent welding connection minimizes leakage risks in harsh environments.
- Application Scope: Widely used in oil & gas (upstream wellheads, midstream transmission pipelines, offshore platforms), chemical processing (high-pressure reactors, petrochemical plants), power generation (nuclear/thermal power boiler systems, turbine pipelines), marine (shipboard high-pressure piping), and heavy manufacturing – preferred for high-pressure, high-temperature, or corrosive media applications requiring reliable, long-term piping connections.