This reference page provides the dimensional data, bolt information, weight, and CAD download details for a Weld Neck Flange 12 Inch Class 1500. Use the source values for drafting and preliminary coordination, then verify the selected flange against the project specification before fabrication or installation.
For related design work, compare this information with guidance on pipe schedules, flange types, gasket selection, stud bolts, and CAD/DWG piping references. These topics help connect flange dimensions with the pipe, gasket, bolting, and layout requirements of a complete connection.
Weld Neck Flange 12″ Class 1500
Weld Neck Flange 12″ 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 12″ Class 1500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):12″
- DN Size: DN300
- Outside Diameter:673mm
- Flange Thickness:124mm
- Hub Diameter:451mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:381mm
- Weight: 314kg
- Number of Bolts:16
- Stud Bolt Size: 2″ UNC (or M52) x 375 Long
- Hole Diameter: 2 1/8″ (53.975mm)
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 12″ 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 12″ 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 the Weld Neck Flange Dimensions
The listed outside diameter, flange thickness, hub diameter, raised face diameter, and hole diameter describe the flange geometry used for layout, checking, and fabrication reference. The nominal pipe size identifies the connected piping size designation; it should not be treated as the flange outside diameter.
The bore requires particular attention because it varies with the pipe schedule and wall thickness. A flange can have the correct nominal size and pressure class while still requiring a bore check against the actual pipe selected for the project. Confirm the pipe outside diameter, wall condition, weld preparation, and internal alignment before releasing fabrication drawings.
The raised face is the gasket-contact area. Its diameter should be coordinated with the selected gasket and the mating flange. The bolt quantity, stud size, hole diameter, and stated bolt length should also be checked against the mating flange, washer arrangement, thread engagement, and project bolting specification. The imperial and metric designations shown in the source should not be treated as interchangeable without confirming the applicable procurement and assembly requirements.
Drafting and Installation Checks
- Use the flange dimensions for equipment, piping-layout, and spool-drawing coordination, while keeping the applicable standard and project specification visible on the drawing.
- Match the flange facing and gasket arrangement with the mating component; do not select a gasket from nominal size alone.
- Confirm the pipe schedule and resulting bore before detailing the weld connection.
- Check bolt-hole alignment, stud length, access for tightening, and clearance around the flange during layout review.
- Confirm material, rating requirements, temperature service, inspection requirements, and welding details through the project documents before purchase or fabrication.
The downloadable DWG can support drafting and coordination, but a CAD file does not replace dimensional verification against the approved specification and the actual components being joined.
Frequently Asked Questions
What does a weld neck flange do?
A weld neck flange connects to the pipe through its tapered hub and welded joint. The geometry is intended to provide a robust transition between the pipe and flange and to help manage stress at the connection.
Why does the bore vary for this flange?
The bore is selected to suit the pipe schedule and wall thickness. Therefore, the bore should be confirmed from the actual pipe specification rather than assumed from the nominal pipe size.
What information is provided for the bolt connection?
The source lists the number of bolts, stud bolt designation and length, and hole diameter. These details should be checked with the mating flange and the project bolting requirements before assembly.
Can the DWG be used directly for fabrication?
The DWG is intended as a drafting, detailing, layout, and fabrication reference. Fabrication should proceed only after the drawing is checked against the approved standard, material requirements, pipe bore, gasket arrangement, and project-specific tolerances.
What should be verified before installation?
Verify the flange standard, material, pressure-temperature requirements, pipe schedule, bore, gasket, facing, bolt arrangement, bolt length, welding requirements, and mating-component compatibility. The project engineer or responsible piping authority should approve the final selection.