This reference provides the dimensional data and drafting information for a Weld Neck Flange 3 Inch Class 600. Use the source values when checking flange layouts, preparing piping drawings, or coordinating a flange connection with the selected pipe and gasket.
The flange’s nominal size identifies the connected piping size, while the Class 600 designation identifies the applicable flange pressure class. These terms should be read together with the project’s material, temperature, pressure, and piping specification requirements.
For related design work, see the site’s references on pipe schedules, flange types, pipe dimensions, and CAD/DWG piping resources. Those references help connect the flange dimensions to the pipe, gasket, bolts, and adjacent fittings used in a complete assembly.
Weld Neck Flange 3″ Class 600
Weld Neck Flange 3″ Class 600 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 3″ Class 600 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):3″
- DN Size: DN80
- Outside Diameter:210mm
- Flange Thickness:31.8mm
- Hub Diameter:117mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:127mm
- Weight: 9.1kg
- Number of Bolts:8
- Stud Bolt Size: 3/4″ UNC (or M20) x 125 Long
- Hole Diameter: 7/8″ (22.225mm)
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 3″ Class 600 is commonly used for:
- Process piping systems
- Oil and gas lines
- Water and utility piping
- 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 3″ Class 600, which can be used for drafting, detailing, piping layout coordination, and fabrication reference.
Available Weld Neck Flange Class 600 Sizes
This size is part of the Weld Neck Flange Class 600 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 below is the controlling local reference for this page. Confirm the flange outside diameter, thickness, hub dimensions, raised-face dimension, bolt-hole information, and weight against the project’s approved data before issuing fabrication or installation documents.
Understand the Bore Selection
The bore is not a single universal value for this flange entry. It varies with the pipe schedule and wall thickness selected for the connection. Match the flange bore to the actual pipe and verify the transition at the weld end before detailing the joint.
Check the Bolting and Joint Assembly
The listed stud-bolt size, bolt count, hole diameter, and bolt length describe the reference connection. Final bolting also depends on the mating flange, gasket, washer arrangement, thread engagement, facing condition, and the project’s installation procedure. Do not select a replacement bolt solely by nominal diameter; confirm the complete joint assembly.
Why the Weld Neck Hub Matters
A weld neck flange uses a tapered hub and a butt-welded pipe connection. The hub provides a gradual transition between the pipe and flange, which can help manage local stress compared with less integrated flange arrangements. Its suitability still depends on the piping design, loading, materials, welding procedure, inspection requirements, and applicable engineering review.
Using the DWG File
The downloadable DWG is useful for layout, drafting, detailing, and coordination. Treat it as a reference component: confirm the selected pipe schedule, bore, flange facing, gasket arrangement, mating flange, and project-specific tolerances before using the drawing for fabrication.
When building a complete piping model, link this reference with the relevant Class 600 flange size pages, pipe schedule dimensions, and flange bolt-hole references so that connected components are checked as one assembly.
Frequently Asked Questions
What is the bore of a Weld Neck Flange 3 Inch Class 600?
The bore depends on the pipe schedule and wall thickness selected for the connection. Use the actual pipe specification to determine the matching bore rather than assuming one universal opening.
What bolt size is listed for this flange?
The reference lists 3/4" UNC (or M20) x 125 Long stud bolts, with the stated bolt count and hole diameter. Confirm the complete bolting arrangement against the mating flange, gasket, material specification, and project requirements.
Why is a weld neck flange used?
Its long tapered hub is welded directly to the pipe and provides a gradual transition intended to reduce stress concentration at the flange connection. Selection must still be verified for the actual service and loading conditions.
Can the DWG be used directly for fabrication?
The DWG is provided for drafting, layout, detailing, and fabrication reference. Verify the pipe schedule, bore, facing, gasket, bolting, tolerances, and approved project requirements before releasing fabrication documents.
What should be checked before installation?
Confirm the latest project requirements, flange and pipe materials, pipe schedule, bore, gasket type, bolt length, mating flange, and applicable pressure-temperature requirements before installation.