This reference provides the dimensional data, connection details, and CAD resource for a weld neck flange 2 inch Class 400. Use the listed values when checking a piping layout, preparing a fabrication drawing, or coordinating a flange connection with the associated pipe, gasket, and bolting.
The flange dimensions should be read together with the pipe schedule and project specifications. In particular, the bore is not a single universal value because it depends on the pipe wall thickness. For design work, compare the flange data with the applicable pipe dimensions and schedules, mating flange details, and the project’s material and pressure-temperature requirements.
Weld Neck Flange 2″ Class 400
Weld Neck Flange 2″ Class 400 is widely used in piping systems that require strong, leak-resistant flange connections. It features a long tapered hub that provides excellent stress distribution and is commonly applied in process piping, utility lines, and industrial systems where welding strength and reliability are important.
This dimension data is based on ANSI / ASME B16.5-2020.
Weld Neck Flange 2″ Class 400 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):2″
- DN Size: DN50
- Outside Diameter:165mm
- Flange Thickness:25.4mm
- Hub Diameter:84mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:92.1mm
- Weight: 4.6kg
- Number of Bolts:8
- Stud Bolt Size: 5/8″ UNC (or M16) x 110 Long
- Hole Diameter: 3/4″ (19.05mm)
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 2″ Class 400 is commonly used for:
- Process piping systems
- Oil and gas lines
- Water and utility piping
- Higher pressure service
- Pressure piping connections
- Industrial fabrication and maintenance work
CAD Drawing Download
This page includes the CAD drawing file for Weld Neck Flange 2″ Class 400, which can be used for drafting, detailing, piping layout coordination, and fabrication reference.
Available Weld Neck Flange Class 400 Sizes
This size is part of the Weld Neck Flange Class 400 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 existing reference below separates the flange’s main dimensional features from its installation and application notes. Outside diameter, thickness, hub dimensions, raised-face dimensions, bolt-hole information, and weight support different stages of drafting and procurement. Confirm which dimensions are required by the drawing or fabrication procedure before using the data in a model.
Check the Bore Against the Pipe
A weld neck flange is intended to align with the pipe through its tapered hub and welded connection. The flange bore must be checked against the selected pipe schedule and wall thickness so the connection is represented correctly in a section view, spool drawing, or CAD model. Do not infer the bore from the outside diameter alone.
Understand the Bolting Information
The listed bolt count, stud bolt description, and hole diameter should be reviewed together. Confirm the selected bolting material, thread convention, usable length, gasket arrangement, and tightening procedure against the project specification. The stated alternative metric designation should not be treated as interchangeable without checking the procurement and assembly requirements.
Why the Weld Neck Form Matters
The tapered hub provides a gradual transition between the pipe and flange. This geometry is intended to support a more continuous load path than simpler flange forms, particularly where the piping system experiences pressure, temperature changes, or repeated loading. Final suitability still depends on the complete piping design, material selection, welding procedure, and applicable engineering checks.
Use the CAD File Carefully
The downloadable DWG is useful for layout, detailing, and coordination. Before releasing a drawing, verify units, insertion scale, bore representation, face details, weld preparation, and compatibility with the selected pipe and mating components. CAD geometry is a drafting reference and does not replace project-specific dimensional or engineering verification.
For related work, connect this reference with internal resources covering flange types, pipe schedules, stud bolts, gaskets, ASME B16.5 flange dimensions, and piping CAD/DWG downloads.
Frequently Asked Questions
What does a weld neck flange do?
A weld neck flange connects to the pipe through a butt-welded tapered hub. Its geometry helps distribute loads at the flange-to-pipe transition and is commonly considered where piping connections require a robust welded arrangement.
What is the bore of this flange?
The bore varies with the pipe schedule and wall thickness. Select or verify the bore against the actual pipe specification rather than assuming that every 2 inch pipe uses the same internal opening.
What bolt information is provided?
The reference identifies the bolt count, stud bolt size, nominal length, and hole diameter. Confirm the bolting material, gasket, thread requirements, and tightening method before procurement or installation.
Can the DWG be used for fabrication?
The DWG can support drafting, layout coordination, and fabrication reference. Check its units and geometry against the authoritative dimensions, pipe schedule, project drawings, and fabrication requirements before issuing it for manufacture.
Does Class 400 alone determine the allowable pressure?
No. The applicable pressure-temperature rating depends on factors such as material and service conditions. Use the project specification and the governing flange requirements to verify the allowable rating rather than treating the class designation as a standalone design pressure.