This reference provides the dimensional data, bolt information, weight, and CAD resource for a Weld Neck Flange 4 Inch Class 2500. Use the listed values for preliminary layout, drafting, procurement review, and comparison with related flange configurations.
For accurate selection, read the dimensional list together with the pipe schedule, flange material, gasket requirements, and project pressure-temperature criteria. The flange bore is not a single universal value because it must correspond to the connected pipe wall thickness.
Weld Neck Flange 4″ Class 2500
Weld Neck Flange 4″ 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 4″ Class 2500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):4″
- DN Size: DN100
- Outside Diameter:356mm
- Flange Thickness:76.2mm
- Hub Diameter:165mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:157.2mm
- Weight: 61.5kg
- Number of Bolts:8
- Stud Bolt Size: 1 1/2″ UNC (or M39) x 255 Long
- Hole Diameter: 1 5/8″ (41.275mm)
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 4″ 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 4″ 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 Read This Weld Neck Flange Reference
The nominal pipe size identifies the intended piping connection, while the DN designation provides the corresponding metric reference. These labels describe the connection size; they do not, by themselves, define the actual bore. Confirm the pipe outside diameter, wall thickness, and schedule before preparing fabrication or installation documents.
Why the Bore Requires Special Attention
The source data identifies the bore as dependent on pipe schedule and wall thickness. This is important when a weld neck flange is modeled in CAD or matched with a pipe spool. A mismatch at the bore can affect fit-up, internal alignment, welding preparation, and the final fabrication detail.
Hub, Face, and Bolt Information
The tapered hub is the defining feature of this flange type. It transitions between the flange body and the pipe, so the hub diameter, flange thickness, and raised-face diameter should be kept distinct in drawings and inspection records. Bolt quantity, stud size, and hole diameter should be checked as a group rather than treated as interchangeable specifications.
When reviewing the bolt information, confirm the selected stud material, thread system, usable thread engagement, washer arrangement, gasket thickness, and joint assembly requirements. The listed bolt length is a reference dimension; the final length should be verified against the complete joint stack-up and project specification.
Using the CAD File
The downloadable DWG can support piping layout, equipment coordination, flange identification, and fabrication reference. Before using it for release, verify the drawing units, layer conventions, face orientation, bore representation, and compatibility with the connected pipe and gasket arrangement. CAD geometry should be checked against the authoritative dimension list and the project document set.
Related Piping References
For broader design and drafting work, connect this reference with related resources on pipe schedules, flange types, raised-face flanges, stud bolts, gaskets, and DWG piping details. These topics help explain how the flange dimensions interact with the rest of a bolted piping joint.
Frequently Asked Questions
What does a weld neck flange do?
A weld neck flange connects to the pipe through its tapered hub and is intended for applications where a robust welded flange connection and controlled stress transition are important. The final application requires project-specific engineering verification.
Why is the bore listed as variable?
The bore depends on the connected pipe schedule and wall thickness. Select or verify the bore only after the pipe specification has been established.
What bolt information is provided for this flange?
The reference lists the bolt quantity, stud bolt size, and hole diameter. Confirm these details with the applicable flange specification, mating flange, gasket, bolting material, and joint assembly requirements.
Can the DWG be used directly for fabrication?
The DWG is provided as a drafting and fabrication reference. Check its units, geometry, bore, face details, and project-specific requirements before issuing it for manufacture or construction.
Which standard is identified for the dimensions?
The source identifies ANSI / ASME B16.5 as the reference standard and states that the dimension data is based on ANSI / ASME B16.5-2020. Confirm the applicable project edition and procurement requirements before final use.