This reference provides dimensional and drafting information for a Weld Neck Flange 10 Inch Class 900. Use the listed values when reviewing flange layouts, preparing piping details, or coordinating the flange with the connected pipe, gasket, and bolting.
The most important selection detail is the flange-to-pipe interface. While the flange outside dimensions and bolt arrangement are defined in the reference data, the bore must be checked against the pipe schedule and wall thickness. For that reason, this page should be used together with the applicable pipe dimensions and schedule reference.
Weld Neck Flange 10″ Class 900
Weld Neck Flange 10″ Class 900 is widely used in piping systems that require strong, leak-resistant flange connections under high-pressure service. It features a long tapered hub that provides excellent stress distribution and is commonly applied in process piping, utility lines, refineries, power plants, and industrial systems where welding strength and reliability are essential.
This dimension data is based on ANSI / ASME B16.5-2020.
Weld Neck Flange 10″ Class 900 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):10″
- DN Size: DN250
- Outside Diameter:546mm
- Flange Thickness:69.8mm
- Hub Diameter:368mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:323.8mm
- Weight: 132kg
- Number of Bolts:16
- Stud Bolt Size: 1 3/8″ UNC (or M36) x 235 Long
- Hole Diameter: 1 1/2″ (38.1mm)
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 10″ Class 900 is commonly used for:
- Process piping systems
- Oil and gas lines
- Refinery and petrochemical piping
- Very 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 10″ Class 900, which can be used for drafting, detailing, piping layout coordination, and fabrication reference.
Available Weld Neck Flange Class 900 Sizes
This size is part of the Weld Neck Flange Class 900 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 dimensional list identifies the principal geometry needed for layout and detailing, including the flange outside diameter, thickness, hub diameter, raised face, bolt count, bolt-hole diameter, and stud bolt information. These values support drawing coordination, but they do not replace a project review of materials, fabrication requirements, gasket selection, or pressure-temperature conditions.
Check the Bore Against the Pipe
The bore is not a single universal value for every pipe connection. It varies with the selected pipe schedule and wall thickness, so the flange bore should be verified against the actual pipe specification before fabrication. This is a key coordination point between flange dimensions, pipe schedules, and weld detailing.
Understand the Weld Neck Geometry
The tapered hub provides a gradual transition from the flange body to the pipe. In service, this geometry is intended to reduce stress concentration compared with a shorter flange arrangement, particularly where pressure, temperature changes, or cyclic loading are part of the design basis. The weld itself still requires appropriate engineering, welding, inspection, and project-specification review.
Bolting and Facing Coordination
Use the listed bolt count, stud bolt size, bolt length, and hole diameter when preparing a preliminary connection detail. Final bolting should be checked with the selected flange material, gasket, facing arrangement, tightening procedure, and installation clearance. Related PipeSTD references for flange types, pipe schedules, gaskets, and piping terminology can help complete this coordination.
CAD and Drafting Workflow
The downloadable DWG can support piping layouts, equipment-interface studies, fabrication sketches, and dimensional coordination. Confirm units, drawing scale, face orientation, weld preparation details, and the final bore before using the file for fabrication or issuing it as a construction document.
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. Its geometry provides a gradual transition intended to improve stress distribution at the flange-to-pipe connection.
Does the flange bore have one fixed dimension?
No. The bore varies according to the connected pipe schedule and wall thickness. Confirm the pipe specification before selecting or fabricating the flange.
What should be checked before ordering the bolts?
Check the listed stud bolt size, length, bolt count, and hole diameter against the flange details. Also verify the material specification, gasket, facing, tightening method, and project requirements.
Can the DWG be used directly for fabrication?
The DWG is useful as a drafting and coordination reference, but fabrication should proceed only after confirming units, bore, weld details, materials, tolerances, and the project-approved design information.
Is Class 900 alone enough to select the flange?
No. Selection also requires review of the applicable standard, material, service conditions, pipe connection, gasket, bolting, and project pressure-temperature requirements.