This reference provides dimensional and connection information for a Weld Neck Flange 12 Inch Class 2500, including the listed flange geometry, bolt details, weight, and CAD drawing resource. Use the technical values on this page as the primary reference for drafting and coordination, then verify them against the applicable project documents before fabrication.
The flange’s tapered hub is welded to the pipe and forms part of the load-transfer path between the pipe and flange. Because the bore depends on the connected pipe wall or schedule, the flange should be selected together with the applicable pipe dimensions and schedules, gasket arrangement, material specification, and project pressure-temperature requirements.
Weld Neck Flange 12″ Class 2500
Weld Neck Flange 12″ Class 2500 is widely used in piping systems that require strong, leak-resistant flange connections under extremely high-pressure service. It features a long tapered hub that provides excellent stress distribution and is commonly applied in refineries, petrochemical plants, power generation systems, and critical industrial piping where welding strength and connection reliability are essential.
This dimension data is based on ANSI / ASME B16.5-2020.
Weld Neck Flange 12″ Class 2500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):12″
- DN Size: DN300
- Outside Diameter:762mm
- Flange Thickness:184.2mm
- Hub Diameter:441mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:381mm
- Weight: 575kg
- Number of Bolts:12
- Stud Bolt Size: 2 3/4″ UNC (or M72) x 540 Long
- Hole Diameter: 2 7/8″ (73.025mm)
What Is a Weld Neck Flange?
A weld neck flange is a type of pipe flange designed with a long tapered hub that is welded directly to the pipe. This design helps reduce stress concentration at the flange base and provides better strength under pressure, temperature fluctuation, and cyclic loading.
Common Applications
Weld Neck Flange 12″ Class 2500 is commonly used for:
- Process piping systems
- Oil and gas lines
- Refinery and petrochemical piping
- Extremely high-pressure service
- Pressure piping connections
- Industrial fabrication and maintenance work
CAD Drawing Download
This page includes the CAD drawing file for Weld Neck Flange 12″ Class 2500, which can be used for drafting, detailing, piping layout coordination, and fabrication reference.
Available Weld Neck Flange Class 2500 Sizes
This size is part of the Weld Neck Flange Class 2500 series. Check other sizes in the same category to find matching dimension data and CAD files for your project.
Notes
Before fabrication or installation, always confirm the latest project requirements, flange material specification, pipe schedule, bore size, gasket type, bolt length, and applicable pressure-temperature rating.
How to Use This Flange Reference
The dimension list identifies the main features needed for layout, modeling, procurement review, and fabrication coordination. Outside diameter, thickness, hub geometry, raised-face dimensions, bolt-hole information, and stud-bolt details should be checked together rather than treated as separate design decisions.
The stated bore is not a single universal value for every installation. It varies with the pipe schedule and wall thickness selected for the connection. Confirming the mating pipe before creating a final model or fabrication drawing helps avoid an incorrect internal opening or a mismatch at the weld preparation.
Connection and Drafting Considerations
- Match the flange face arrangement with the specified gasket and mating flange.
- Coordinate the bolt-hole pattern with the companion flange and confirm bolt clearance in the assembly.
- Review stud-bolt size and length against the actual flange stack-up, gasket thickness, washers, and installation requirements.
- Use the downloadable DWG as a drafting aid, not as a substitute for checking the project specification or approved fabrication documents.
- Confirm material, pipe schedule, bore, gasket, and pressure-temperature requirements before release for fabrication or installation.
Why the Weld Neck Form Matters
A weld neck flange uses a long tapered hub to provide a gradual transition from the flange into the pipe. This configuration is commonly considered where connection strength, stress distribution, temperature variation, and cyclic service require careful engineering review. Final suitability depends on the complete piping design, materials, joining procedure, and applicable project requirements.
For related research, connect this page to internal references covering flange types, pipe schedules, stud bolts and nuts, gaskets, and piping drawing symbols.
Frequently Asked Questions
What does Class 2500 identify on this flange?
Class 2500 identifies the flange pressure-class designation used for the dimensional and rating system referenced on this page. It should not be treated as a standalone allowable pressure. Material, temperature, fluid, joint details, and the governing project requirements must also be reviewed.
Why does the bore vary with pipe schedule?
The bore must suit the internal opening and wall configuration of the connected pipe. Since pipe wall thickness can change with schedule, the required flange bore may also change. Confirm the pipe selection before finalizing the flange or CAD model.
Can the DWG file be used for fabrication?
The DWG is useful for drafting, layout coordination, and reference. Before fabrication, verify the drawing against the listed source data, the project specification, the selected pipe, gasket and bolt assembly, and the approved fabrication requirements.
What should be checked before installation?
Check the companion flange, face and gasket arrangement, bolt-hole alignment, stud-bolt details, pipe bore, materials, and applicable installation requirements. A qualified engineer or responsible piping professional should resolve any design or fit-up uncertainty.