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DTC‑LWN‑SS/CS Series
DTC supplies forged Long Weld Neck Flanges (LWN Flanges) manufactured according to ASME B16.5 and ASME B16.47 standards. Available in carbon steel, stainless steel, and alloy steel, designed for high-pressure piping, pressure vessels, and industrial process systems.
A Long Weld Neck Flange (LWN Flange) is a specialized flange with an extended tapered hub that provides a smooth transition between the pipe and flange body. Unlike standard weld neck flanges, the extended neck is longer and can function as an integrated pipe nozzle, providing additional reinforcement and stability.
Long weld neck flanges are commonly used in pressure vessels, heat exchangers, towers, reactors, and high-pressure piping systems where enhanced strength, alignment, and stress distribution are required.
DTC manufactures and supplies forged long weld neck flanges in carbon steel, stainless steel, and alloy steel according to international standards including ASME B16.5, ASME B16.47, and customer-specific requirements.
The long tapered hub provides a smooth connection between the flange and pipe, reducing stress concentration.
The reinforced neck design improves resistance against bending, vibration, and thermal stress.
LWN flanges are commonly specified for demanding services involving high pressure and high temperature.
The extended neck can be used as a vessel nozzle connection, reducing the need for additional components.
The butt weld design provides a strong, permanent connection with excellent sealing performance.
| Item | Description |
|---|---|
| Product Name | Long Weld Neck Flange / LWN Flange |
| Standard | ASME B16.5 / ASME B16.47 / Customer Requirements |
| Manufacturing Method | Forged |
| Size Range | NPS 1/2″ – 60″ (depending on standard) |
| Pressure Class | Class 150, 300, 600, 900, 1500, 2500 |
| Material | Carbon Steel, Stainless Steel, Alloy Steel |
| Facing Type | RF, FF, RTJ |
| Connection Type | Butt Weld |
| Common Grades | ASTM A105, A350 LF2, A182 F304/F316 |
| Applicable Media | Oil, Gas, Steam, Chemical Fluids |
| Inspection | EN10204 3.1 MTC Available |
Typical grades:
Applications:
Typical grades:
Applications:
Typical grades:
Applications:
DTC Long Weld Neck Flanges are widely used in:
Typical applications:
| Feature | Long Weld Neck Flange | Weld Neck Flange |
|---|---|---|
| Neck Length | Longer extended hub | Standard tapered hub |
| Strength | Higher reinforcement | High |
| Main Application | Pressure vessels, equipment nozzles | General high-pressure piping |
| Stress Distribution | Excellent | Excellent |
| Cost | Higher | Lower |
| Installation | More specialized | More common |
| Feature | Long Weld Neck Flange | Slip-On Flange |
|---|---|---|
| Connection | Butt weld | Fillet weld |
| Pressure Capability | High | Medium |
| Strength | Higher | Lower |
| Installation | More complex | Easier |
| Application | Critical systems | General piping |
| Cost | Higher | Lower |
| Feature | Long Weld Neck Flange | Blind Flange |
|---|---|---|
| Function | Pipe/equipment connection | Pipeline closure |
| Design | Extended neck with bore | Solid plate |
| Application | Pressure equipment | Isolation and testing |
| Flow Passage | Yes | No |
DTC provides specialized flange solutions with reliable manufacturing resources and strict quality control.
Available:
DTC supports:
Available documents:
A Long Weld Neck Flange is a flange with an extended tapered hub designed for high-pressure piping and pressure vessel applications.
The main difference is the length of the hub. A long weld neck flange has an extended neck that provides additional reinforcement and can act as a vessel nozzle.
They are commonly used in pressure vessels, reactors, heat exchangers, towers, and high-pressure industrial piping systems.
Common standards include ASME B16.5, ASME B16.47, ASTM material standards, and customer-specific requirements.
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