This reference provides the dimensional data, weight, bolt details, and CAD resource for a Weld Neck Flange 3/4 Inch Class 600. Use the listed values when checking flange layouts, piping details, and fabrication drawings, while treating the local dimension data as the controlling reference for this page.
The most important selection point is coordination between the flange, mating flange, pipe schedule, gasket, and bolting. A weld neck flange may share the same nominal pipe size with different pipe wall conditions, so the bore and weld preparation should be checked against the pipe information used in the project.
Weld Neck Flange 3/4″ Class 600
Weld Neck Flange 3/4″ 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 3/4″ Class 600 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):3/4″
- DN Size: DN20
- Outside Diameter:117mm
- Flange Thickness:15.7mm
- Hub Diameter:48mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:42.9mm
- Weight: 1.4kg
- Number of Bolts:4
- Stud Bolt Size: 5/8″ UNC (or M16) x 90 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 3/4″ 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 3/4″ 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 Read This Weld Neck Flange Reference
The dimension list identifies the flange envelope and connection details, including outside diameter, thickness, hub diameter, raised face diameter, bolt-hole information, and overall bolting requirements. These values support drafting and dimensional coordination; they do not replace a project specification, fabrication drawing, or engineering review.
Nominal size, bore, and pipe schedule
NPS and DN identify the nominal connection size rather than a guaranteed measured bore. The bore is specifically noted as dependent on pipe schedule and wall thickness. For that reason, select the bore only after confirming the pipe schedule and the weld-neck flange bore required by the piping design. This is also an important cross-check when comparing related pipe dimensions and schedules references.
Class designation and flange matching
The Class 600 designation identifies the flange class used for matching and specification purposes. It should not be treated as a standalone allowable-pressure value. Final pressure-temperature suitability depends on the applicable standard, material, temperature, gasket, bolting, and project requirements. The mating flange should be checked for compatible facing, bolt-hole pattern, and nominal size before fabrication or installation.
Bolts, gasket, and CAD coordination
The listed stud bolt description includes both an inch designation and a metric alternative. These options should not be mixed casually: confirm the project bolting system, thread form, length, nuts, washers, and flange assembly requirements. Also coordinate the raised face and gasket selection with the applicable flange and gasket reference.
The downloadable DWG is useful for piping layout, detailing, and preliminary coordination. Before issuing a drawing for fabrication, verify the CAD geometry against the page dimensions and the current project documents. Related weld neck flange Class 600 sizes can help when building a consistent flange library or comparing adjacent nominal sizes.
Weld Neck Flange 3/4 Inch Class 600 FAQ
What does the weld neck flange hub do?
The tapered hub provides a gradual transition from the flange body to the pipe. This geometry helps distribute stress more smoothly than a short, flat flange arrangement, subject to proper welding, material selection, and engineering verification.
Is the bore fixed for this flange?
No. The reference identifies the bore as dependent on pipe schedule and wall thickness. Confirm the connected pipe details before selecting or fabricating the flange.
Can the listed 5/8 inch UNC and M16 bolting options be used interchangeably?
Do not assume that they are interchangeable. Confirm the project standard, thread compatibility, nut and washer requirements, bolt length, and mating flange details before assembly.
What should be checked before installation?
Check the flange material, pipe schedule, bore, gasket, facing, bolt pattern, bolting system, bolt length, and applicable pressure-temperature requirements. The project specification and engineering review should govern where they differ from a general reference.