This reference provides the dimensional and drafting information for a Weld Neck Flange 1 Inch Class 2500. Use the listed data when checking flange details against the connected pipe, gasket arrangement, bolting, and project requirements.
The page is also intended to support piping layout and fabrication workflows. Pair this reference with related resources on pipe schedules, flange types, raised-face flanges, and piping CAD files when developing or reviewing a piping detail.
Weld Neck Flange 1″ Class 2500
Weld Neck Flange 1″ 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 1″ Class 2500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):1″
- DN Size: DN25
- Outside Diameter:159mm
- Flange Thickness:35.1mm
- Hub Diameter:57mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:50.8mm
- Weight: 5kg
- Number of Bolts:4
- Stud Bolt Size: 7/8″ UNC (or M24) x 140 Long
- Hole Diameter: 1″ (25.4mm)
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 1″ 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 1″ 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 the Weld Neck Flange Dimensions
The dimensional list identifies the flange envelope, connection details, and reference information needed for preliminary drafting. The outside diameter and flange thickness describe the main flange body, while the hub diameter relates to the tapered weld neck that transitions into the pipe.
The bore diameter is not a single universal value for this flange entry. It depends on the selected pipe schedule and wall thickness, so the bore should be checked against the actual pipe specification before fabrication or installation. This is an important coordination step when connecting flange data with a pipe-dimensions or pipe-schedule reference.
Bolting and Facing Checks
The source data identifies four bolts, the stud bolt size, and the hole diameter. These details should be coordinated with the mating flange, gasket selection, bolt material, tightening procedure, and available clearance. Do not treat the flange class alone as a substitute for a project-specific pressure-temperature or material check.
The raised-face diameter should also be reviewed with the mating flange and gasket arrangement. Face condition, alignment, welding sequence, and final bolt-up can affect connection performance, so fabrication drawings should be checked against the governing project documents.
Using the CAD File
The downloadable DWG can help with layout coordination, detailing, and fabrication reference. Before using the drawing as a final manufacturing document, confirm the bore, pipe schedule, facing arrangement, material, tolerances, and any project-specific revisions. Related internal references for flange dimensions, weld neck flange sizes, and DWG piping details can help compare adjacent components without replacing the source-of-truth dimensional data.
Frequently Asked Questions
What is a Weld Neck Flange 1 Inch Class 2500?
It is a weld neck flange reference for NPS 1, also identified as DN25, with a Class 2500 designation. The flange uses a tapered hub and is welded directly to the pipe.
Why does the bore depend on the pipe schedule?
The flange bore must match the inside configuration of the connected pipe. Because pipe wall thickness varies by schedule, the correct bore should be confirmed from the selected pipe specification rather than assumed from nominal pipe size alone.
What stud bolt information is listed?
The source lists four studs with a 7/8 inch UNC or M24 designation and a listed length of 140. Confirm the final bolting arrangement with the mating flange, gasket, material requirements, and project specification.
Can the DWG be used directly for fabrication?
The DWG is useful for drafting, layout coordination, and fabrication reference. It should be reviewed against the approved project documents and checked for pipe schedule, bore, material, facing, tolerances, and revision status before release for manufacture.
Does Class 2500 alone establish the allowable working pressure?
No. The applicable pressure-temperature capability depends on the governing standard, material, temperature, and project requirements. Confirm the rating with the approved engineering documents before design or installation.