This reference provides the source dimensions and connection details for a Weld Neck Flange 5 Inch Class 2500, including outside diameter, thickness, hub diameter, weight, bolt quantity, stud size, and hole diameter. Use the listed values for drafting and preliminary coordination, while confirming project-specific requirements before fabrication or installation.
The page also explains how the tapered weld-neck hub, pipe bore, gasket, studs, and CAD file relate to flange selection. For additional coordination, compare this entry with the related pipe schedules, flange dimensions, fittings, and piping terminology references on PipeSTD.
Weld Neck Flange 5″ Class 2500
Weld Neck Flange 5″ 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 5″ Class 2500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):5″
- DN Size: DN125
- Outside Diameter:419mm
- Flange Thickness:91.9mm
- Hub Diameter:203mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:185.7mm
- Weight: 102kg
- Number of Bolts:8
- Stud Bolt Size: 1 3/4″ UNC (or M45) x 300 Long
- Hole Diameter: 1 7/8″ (47.625mm)
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 5″ 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 5″ 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 size identifies the intended piping size, while the flange dimensions describe the external geometry used for layout, drilling, mating, and fabrication checks. The outside diameter and flange thickness are useful for modeling envelope space, and the hub diameter helps represent the tapered transition between the flange and the pipe.
The bore is not a single fixed value in this reference because it varies with pipe schedule and wall thickness. This is an important drafting and procurement check: the flange bore should be reviewed against the actual pipe selected for the project rather than assumed from nominal pipe size alone.
Bolting and gasket coordination
The listed bolt quantity, stud size, bolt length, and hole diameter describe the bolted connection shown by the source data. They should be checked together with the mating flange, gasket selection, washer requirements, tightening procedure, and project specifications. A matching nominal size does not by itself confirm that two flanges are interchangeable.
Using the CAD drawing
The downloadable DWG can support piping layouts, equipment coordination, detailing, and fabrication reference. Before issuing a drawing, verify the flange orientation, weld preparation, bore, facing arrangement, mating component, and any project-specific drafting conventions against the approved design information.
Design and installation checks
- Confirm the pipe schedule and resulting bore.
- Verify material, gasket, and pressure-temperature requirements.
- Check the mating flange and bolt-hole alignment.
- Confirm stud length and assembly details for the selected joint.
- Use the applicable project specification and current governing requirements before fabrication.
Frequently Asked Questions
What is a weld neck flange?
A weld neck flange has a long tapered hub and is welded directly to the pipe. The hub provides a gradual transition that can help reduce stress concentration at the flange connection.
What is the bore of the Weld Neck Flange 5 Inch Class 2500?
The bore varies according to the pipe schedule and pipe wall thickness. Select or verify the bore against the actual pipe specification rather than relying only on the nominal size.
How many bolts are listed for this flange?
The source data lists eight bolts. Confirm the mating flange drilling and the complete bolting assembly before ordering or installation.
What stud bolt information is provided?
The reference lists a stud bolt size of 1 3/4 inch UNC, or M45, with a length of 300. Confirm the required thread form, material, length, and tightening requirements with the project specification.
Can the DWG file be used for fabrication?
The DWG is provided as a drafting, detailing, layout, and fabrication reference. It should be checked against approved project documents and the final pipe, gasket, flange, and material requirements before release for fabrication.
Which standard is identified for the dimension data?
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 requirements and current governing documents before use.