This reference provides the dimensional and connection details for a Weld Neck Flange 3/4 Inch Class 1500. Use the listed values for drafting, flange identification, preliminary coordination, and checking component compatibility.
For accurate selection, review the dimensional list together with the pipe schedule, flange facing requirements, gasket specification, material requirements, and project pressure-temperature criteria. The flange class identifies a standardized rating category; it should not be treated as a standalone design pressure without checking the applicable material and service conditions.
Weld Neck Flange 3/4″ Class 1500
Weld Neck Flange 3/4″ Class 1500 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 1500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):3/4″
- DN Size: DN20
- Outside Diameter:130mm
- Flange Thickness:25.4mm
- Hub Diameter:44mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:42.9mm
- Weight: 2.7kg
- Number of Bolts:4
- Stud Bolt Size: 3/4″ UNC (or M20) x 115 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 3/4″ Class 1500 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 3/4″ Class 1500, which can be used for drafting, detailing, piping layout coordination, and fabrication reference.
Available Weld Neck Flange Class 1500 Sizes
This size is part of the Weld Neck Flange Class 1500 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 dimension section identifies the main geometry needed for piping layout and detailing, including the outside diameter, thickness, hub diameter, raised face diameter, bolt-hole information, and overall bolt quantity. These values help establish the flange envelope and support coordination with mating flanges, gaskets, bolts, and adjacent pipe.
Bore and Pipe Schedule Compatibility
The bore is not a universal value for every pipe installation. It varies with the selected pipe schedule and wall thickness, so the bore should be confirmed against the actual pipe specification before fabrication or procurement. This is especially important when preparing a weld detail or checking internal flow passage continuity.
Understanding the Bolt Information
The listed stud bolt size and hole diameter describe the bolting arrangement associated with this flange reference. Confirm the required bolt material, thread form, length, washers, and tightening procedure against the project specification. Bolt length can also be affected by gasket thickness, facing configuration, and the mating flange arrangement.
Weld Neck Geometry and Drafting
The tapered hub transitions from the flange body toward the pipe and is welded directly to the pipe. In a drawing, show the flange orientation, weld connection, facing, bore relationship, and mating components clearly. The available DWG file can support layout work and drafting reference, but fabrication documents should still be checked against the approved project requirements.
Related Pipe and Flange References
For broader coordination, compare this page with related pipe schedule, flange facing, stud bolt, gasket, and Class 1500 flange references on PipeSTD. Reviewing matching flange sizes and other weld neck flange entries can help identify compatible layouts and CAD resources.
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 is intended to provide a gradual transition between the pipe and flange connection.
What does the Class 1500 designation mean?
Class 1500 is a flange class designation used to identify a standardized pressure-temperature rating category. The applicable rating must be verified using the flange material, temperature, fluid service, and governing project requirements.
Is the bore the same for every 3/4-inch pipe?
No. The listed bore varies with pipe schedule and wall thickness. Confirm the actual pipe specification before selecting or fabricating the flange assembly.
Can the listed bolt size be used without further checks?
The listed bolt size is a reference for this flange configuration. Confirm bolt material, length, gasket arrangement, mating flange details, and tightening requirements before installation.
What is the DWG file used for?
The DWG file can assist with piping layouts, detailing, coordination, and fabrication reference. It should not replace approved drawings, project specifications, or engineering verification.