This reference provides the published dimensions and connection details for a Weld Neck Flange 20 inch Class 1500. Use the data for preliminary piping layout, drafting, procurement review, and fabrication coordination while keeping the project specification as the controlling requirement.
The page also explains how to interpret the flange geometry, bolt information, bore selection, and downloadable CAD resource. For related design work, compare this entry with the site’s pipe schedule, flange types, bolt dimensions, and piping terminology references.
Weld Neck Flange 20″ Class 1500
Weld Neck Flange 20″ 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 20″ Class 1500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):20″
- DN Size: DN500
- Outside Diameter:984mm
- Flange Thickness:177.8mm
- Hub Diameter:641mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:584.2mm
- Weight: 1022kg
- Number of Bolts:16
- Stud Bolt Size: 3″ UNC (or M76) x 540 Long
- Hole Diameter: 3 1/8″ (79.375mm)
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 20″ 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 20″ 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 Read This Weld Neck Flange Reference
The outside diameter, thickness, hub diameter, and raised face diameter describe the principal envelope and facing features used when coordinating a flange with adjoining piping. These dimensions are useful for checking clearances, matching connection details, and preparing fabrication or layout drawings.
The bore is not a single universal dimension in this entry. It varies with the selected pipe schedule and wall thickness, so the mating pipe specification must be confirmed before the flange is ordered, machined, or shown as a final fabrication detail.
Bolt and Connection Details
The listed bolt count, stud bolt size, bolt length, and hole diameter should be reviewed together rather than treated as independent drafting values. They support bolt-circle coordination and help identify the hardware required for assembly. Confirm the project’s gasket, bolting material, tightening procedure, and flange-facing requirements before installation.
Because a weld neck flange is welded directly to the pipe through its tapered hub, the weld preparation and pipe wall compatibility require detailed review. Do not use the flange envelope alone to establish a welding procedure or approve a pressure connection.
Using the CAD File
The downloadable DWG is intended to support drafting, piping layout coordination, detailing, and fabrication reference. Before incorporating it into a final drawing, check units, layer conventions, mating-pipe bore, facing details, and the project revision status. A CAD file should be treated as a reference resource and checked against the applicable project documents.
Related Reference Topics
- Pipe schedules: use schedule information to resolve the flange bore and mating pipe wall.
- Flange terminology: compare weld neck, slip-on, blind, and other flange configurations.
- Bolting references: review stud, nut, hole, and tightening terminology used in flange assemblies.
- CAD and DWG resources: use related downloadable drawings for layout and detailing workflows.
Frequently Asked Questions
What does the bore diameter depend on?
The bore depends on the selected pipe schedule and pipe wall thickness. Confirm the mating pipe specification before finalizing the flange or CAD detail.
Why is a weld neck flange used?
Its long tapered hub is welded directly to the pipe and helps distribute stress at the flange connection. The final suitability of the connection still depends on the complete design, material, welding, and service requirements.
What information is provided for bolting?
The reference lists the number of bolts, stud bolt size, stud length, and hole diameter. These details should be checked against the project bolting and gasket requirements before installation.
Can the DWG be used for fabrication?
The DWG can support drafting, layout coordination, detailing, and fabrication reference. Verify the file against the current project requirements and the applicable flange, pipe, welding, and inspection documentation before fabrication.
What should be confirmed before purchase or installation?
Confirm the flange material, pipe schedule, bore, gasket type, bolt length, pressure-temperature requirements, facing details, and applicable project specifications.