This reference provides the local dimension data for a Weld Neck Flange 16 Inch Class 400, including flange geometry, weight, bolt information, and CAD download access. Use the listed values for drafting and preliminary coordination, then verify the completed connection against the project specification.
Weld neck flanges are selected when the connection requires a butt-welded flange with a tapered hub. The hub and weld interface should be considered together with the pipe schedule, material specification, gasket arrangement, and applicable design conditions.
Weld Neck Flange 16″ Class 400
Weld Neck Flange 16″ Class 400 is widely used in piping systems that require strong, leak-resistant flange connections. It features a long tapered hub that provides excellent stress distribution and is commonly applied in process piping, utility lines, and industrial systems where welding strength and reliability are important.
This dimension data is based on ANSI / ASME B16.5-2020.
Weld Neck Flange 16″ Class 400 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):16″
- DN Size: DN400
- Outside Diameter:648mm
- Flange Thickness:63.5mm
- Hub Diameter:483mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:469.9mm
- Weight: 168kg
- Number of Bolts:20
- Stud Bolt Size: 1 3/8″ UNC (or M36) x 220 Long
- Hole Diameter: 1 1/2″ (38.1mm)
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 16″ Class 400 is commonly used for:
- Process piping systems
- Oil and gas lines
- Water and utility piping
- Higher pressure service
- Pressure piping connections
- Industrial fabrication and maintenance work
CAD Drawing Download
This page includes the CAD drawing file for Weld Neck Flange 16″ Class 400, which can be used for drafting, detailing, piping layout coordination, and fabrication reference.
Available Weld Neck Flange Class 400 Sizes
This size is part of the Weld Neck Flange Class 400 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 separates the main flange features used in piping layout and fabrication drawings: outside diameter, flange thickness, hub diameter, raised face diameter, bolt-hole information, and stud-bolt requirements. These dimensions help establish the connection envelope and support coordination with adjacent flanges, valves, fittings, and pipe.
Bore and pipe schedule
The bore is identified as dependent on the pipe schedule and wall thickness. This is important because the flange outside geometry does not by itself define the opening through the flange. Before detailing the weld end, match the bore to the selected pipe and confirm the transition required by the fabrication specification.
Bolts, holes, and facing
The bolt count, stud-bolt callout, and hole diameter serve different purposes. The bolt count identifies the required pattern, the stud-bolt callout identifies the intended fastener designation and length, and the hole diameter describes the clearance opening in the flange. Confirm bolt compatibility, washer requirements, tightening procedure, and gasket selection before installation. The raised-face dimension should also be coordinated with the mating flange and gasket type.
Design and drafting checks
- Confirm the flange class and the applicable pressure-temperature requirements for the service.
- Match the bore to the pipe schedule and wall thickness shown on the piping design.
- Check the mating flange, bolt circle, hole alignment, gasket, and available stud length.
- Verify material, facing, welding, inspection, and fabrication requirements against the project documents.
- Use the linked CAD/DWG flange drawing as a drafting reference, not as a substitute for approved fabrication documents.
For related design work, connect this reference with internal resources on pipe schedules, flange dimensions, raised-face flanges, stud bolts, gasket selection, and piping CAD blocks. These topics help explain how the flange data fits into a complete piping connection.
Weld Neck Flange 16 Inch Class 400 FAQ
What is a weld neck flange?
A weld neck flange has a long tapered hub and is welded directly to the pipe. Its geometry provides a gradual transition between the pipe and flange and is commonly considered where connection strength, stress distribution, and cyclic service are important.
Does the listed flange bore apply to every pipe schedule?
No. The bore depends on the pipe schedule and wall thickness. Select or verify the bore against the actual pipe specification before producing a fabrication drawing.
Are the stud-bolt size and hole diameter the same thing?
No. The stud-bolt callout identifies the fastener designation and length, while the hole diameter identifies the opening through the flange. Both must be checked for compatibility with the mating flange and installation method.
Can the DWG file be used for fabrication?
The DWG file is useful for drafting, layout coordination, and reference. Fabrication should proceed only after the drawing, material, dimensions, bore, gasket, fasteners, and project requirements have been reviewed and approved.
What should be verified before installation?
Confirm the latest project requirements, flange material, pipe schedule, bore, gasket type, bolt length, facing arrangement, and applicable pressure-temperature rating before installation.