This reference page provides the dimensional and connection details for a 1 1/2 inch Class 2500 weld neck flange, including the flange geometry, bolt arrangement, stud information, and hole size listed in the local reference data.
Use the dimensions together with the applicable pipe schedule, gasket selection, material specification, and project requirements. The bore is schedule-dependent, so it should be checked against the mating pipe before fabrication or installation.
Weld Neck Flange 1 1/2″ Class 2500
Weld Neck Flange 1 1/2″ 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 1/2″ Class 2500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):1 1/2″
- DN Size: DN40
- Outside Diameter:203mm
- Flange Thickness:44.4mm
- Hub Diameter:79mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:73mm
- Weight: 10.5kg
- Number of Bolts:4
- Stud Bolt Size: 1 1/8″ UNC (or M30) x 170 Long
- Hole Diameter: 1 1/4″ (31.75mm)
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 1/2″ 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 1/2″ 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 Weld Neck Flange Reference
The dimensional list is intended for piping design review, drafting, procurement checking, and fabrication coordination. The outside diameter, thickness, hub dimensions, raised face, bolt count, and hole information describe the flange geometry, while the stud information supports connection and detailing checks.
A weld neck flange is welded directly to the pipe through its tapered hub. Unlike a loose flange arrangement, the hub forms part of the transition between the pipe and flange. This makes correct alignment, weld preparation, pipe wall compatibility, and inspection requirements important during fabrication.
Important Bore and Mating-Part Checks
- Confirm the pipe schedule before selecting or approving the bore, because the source data identifies the bore as dependent on pipe wall thickness.
- Compare the flange face and bolt-hole arrangement with the mating flange, gasket, and bolting specification.
- Check that the stated stud length is appropriate for the complete joint stack, including flange thickness, gasket, washers where specified, and nut engagement.
- Verify material, temperature conditions, pressure-temperature requirements, and project quality requirements before release for fabrication.
Useful Related References
For broader design and drafting work, this page can be reviewed alongside references covering pipe schedules, flange types, raised-face flange terminology, and piping bolt and gasket selection. The related CAD/DWG piping resources can also help with layout coordination and preliminary detailing, but the drawing should be checked against the approved project specification before manufacture.
The Class 2500 designation identifies the flange class used for the reference series; it should not be treated as a standalone allowable pressure. Actual suitability depends on the applicable material, temperature, fluid service, joint design, and governing project requirements.
Frequently Asked Questions
What does the bore depend on for this weld neck flange?
The bore depends on the pipe schedule and pipe wall thickness. Confirm the mating pipe details before ordering, machining, or welding the flange.
Why is the tapered hub important?
The tapered hub provides the transition from the flange to the pipe and helps distribute stress through the connection. Proper welding and alignment remain essential to joint performance.
Can the listed bolt information be used without a joint check?
No. The listed stud and hole information should be checked with the mating flange, gasket, washers if specified, nut engagement, and total joint thickness.
What is the CAD file useful for?
The downloadable DWG can support drafting, piping layout coordination, detailing, and fabrication reference. It should be compared with approved project documents before it is used for manufacture.
What should be confirmed before installation?
Confirm the flange material, pipe schedule, bore, gasket, bolt and stud details, pressure-temperature requirements, inspection requirements, and the latest project specification.