ASME B16.5 | WN / WNRF | RF / FF / RTJ | Class 150–2500
Weld Neck Flanges are designed with a long tapered hub and a machined bore that provides a smooth transition between the flange and connecting pipe. The flange is butt-welded directly to the pipe, providing excellent mechanical strength and effective stress distribution.
Weld Neck Flanges are widely used in high-pressure, high-temperature and demanding process applications where reliable performance and reduced stress concentration are important.
Elite supplies Weld Neck Flanges in carbon steel, stainless steel, duplex and super duplex stainless steel, alloy steel, low-temperature carbon steel, nickel alloys and copper-nickel alloys. Products are available to ASME B16.5, applicable ASTM material specifications, international standards and customer project requirements.
| Category | Specification |
|---|---|
| Flange Type | Weld Neck (WN) |
| Common Configuration | Weld Neck Raised Face (WNRF) |
| Nominal Size | NPS 1/2–24 per ASME B16.5; larger sizes available to applicable standards |
| Pressure Classes | 150, 300, 400, 600, 900, 1500, 2500 |
| Facing | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), where applicable |
| Primary Dimensional Standard | ASME B16.5 |
| Large-Diameter Flanges | ASME B16.47, where applicable |
| Pipeline Flanges | MSS SP-44, where applicable |
| Connection | Butt-weld to pipe |
| Bore | Standard bore, XS/XXS or special bore to match pipe ID, where applicable |
| Hub Configuration | Long tapered hub |
| Manufacturing | Forged, in accordance with applicable specifications |
| Surface Finish | Standard or customer-specified |
| Heat Treatment | As required by applicable material specification |
| Inspection | Visual, dimensional, chemical and mechanical testing as applicable |
| NDE | PMI, UT, MT, PT and other NDE methods as specified |
| Documentation | MTC, EN 10204 3.1/3.2, COC and inspection reports |
| Special Requirements | ITP, third-party inspection, NACE / ISO 15156 and customer specifications |
For U.S. process and industrial applications, Elite Weld Neck Flanges are primarily supplied in accordance with ASME B16.5.
Applicable standards may include:
For U.S. applications, ASME B16.5 is the primary dimensional and pressure-rating reference for Weld Neck Flanges from NPS 1/2 through NPS 24.
Carbon Steel
ASTM A105/A105N, ASTM A181, ASTM A350 LF2/LF3 and ASTM A694 F42, F46, F52, F60 and F65.
Stainless Steel
ASTM A182 F304/F304L, F321/F321H, F347/F347H, F316/F316L, F310/F310S, F317 and F904L.
Duplex & Super Duplex
ASTM A182 F51, F53 and F55.
Alloy Steel
ASTM A182 F1, F5, F9, F11, F12, F22, F91 and F92.
Nickel Alloys
Nickel 200/201, Monel 400/K500, Inconel 600/601/625/800/825, Hastelloy C276 and Alloy 20.
Copper-Nickel Alloys
UNS C70600 and C71500, including 90/10 and 70/30 Cu-Ni alloys.
Material selection is based on operating pressure, temperature, process fluid, corrosion conditions, mechanical requirements and applicable project specifications.
Raised Face — RF
The most common Weld Neck configuration for process and industrial piping.
Product designation: WNRF — Weld Neck Raised Face Flange
Flat Face — FF
Used where a full-face mating surface is required, including selected equipment and piping applications.
Product designation: WNFF — Weld Neck Flat Face Flange
Ring Type Joint — RTJ
Designed for demanding high-pressure and high-temperature applications using a metallic ring gasket sealing arrangement.
Product designation: WNRTJ — Weld Neck Ring Type Joint Flange
The long tapered hub of a Weld Neck Flange provides a gradual transition from the flange body to the pipe. This configuration helps distribute stresses through the flange-to-pipe connection and is particularly suitable for demanding piping systems.
Weld Neck Flanges are typically butt-welded to the pipe using an appropriate welding procedure.
Key characteristics include:
Welding and installation should follow the applicable ASME B31 piping code, approved WPS/PQR and project requirements.
Elite Weld Neck Flanges can be supplied with complete quality documentation, including:
Elite supplies:
Weld Neck Flanges are commonly used in:
For quotation, please specify:
NPS + Class + Facing + Material + Bore + Standard + Quantity + Inspection Requirements
Example:
6″ Class 600 Weld Neck Flange, RF, ASME B16.5, ASTM A105N, Standard Bore, MTC EN 10204 3.1.
