This reference provides the dimensions, weight, bolt information, and CAD resource for a 4 inch Class 600 weld neck flange. Use the listed values when checking piping layouts, preparing fabrication drawings, or comparing a flange with related pipe dimensions and schedules.
A weld neck flange is connected to the pipe by welding through its tapered hub. The flange face, bolt circle, bolt holes, hub, and bore must be coordinated with the mating flange, pipe outside diameter, pipe wall condition, gasket, and bolting arrangement. The dimensional list below is the controlling local reference for this page.
Weld Neck Flange 4″ Class 600
Weld Neck Flange 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 4″ Class 600 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):4″
- DN Size: DN100
- Outside Diameter:273mm
- Flange Thickness:38.1mm
- Hub Diameter:152mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:157.2mm
- Weight: 18.7kg
- Number of Bolts:8
- Stud Bolt Size: 7/8″ UNC (or M24) x 145 Long
- Hole Diameter: 1″ (25.4mm)
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 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 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 Use This Weld Neck Flange Reference
The designation combines the nominal pipe size with the flange pressure class. The nominal size identifies the associated piping size, while the class identifies the flange rating category used for specification and selection. These designations should be checked against the project piping class and the applicable material and pressure-temperature requirements.
Why the Bore Requires Attention
The bore is not treated as a single universal value in the source data because it varies with pipe schedule and wall thickness. Before using the flange in a drawing or fabrication package, compare the bore with the selected pipe and confirm the required weld-end detail. This is especially important when coordinating pipe schedules, fittings, valves, and other butt-weld components.
Bolting and Gasket Coordination
Do not select studs from flange size alone. Confirm the bolt-hole diameter, bolt quantity, bolt size and length, gasket type, flange facing, washer requirements, and the mating flange. The available bolt information on this page is a reference for the listed flange; project specifications and the final joint assembly requirements remain controlling.
CAD and Drafting Workflow
The downloadable DWG can support preliminary layout, detailing, and coordination. Treat the drawing as a drafting reference rather than a substitute for checking the dimension list, pipe schedule, weld preparation, gasket arrangement, or fabrication tolerances. Related references for flanges, pipe fittings, and piping terminology can help maintain consistent notation across a piping package.
Frequently Asked Questions
What does 4 inch Class 600 identify?
It identifies the nominal pipe size and the flange pressure class for this weld neck flange reference. Confirm the designation against the project piping specification before procurement or installation.
Why can the bore vary?
The bore depends on the pipe schedule and wall thickness selected for the connection. The flange bore should therefore be checked against the actual pipe and weld-end requirements.
Is the listed bolt information enough to assemble the joint?
No. Also verify the mating flange, gasket, facing, washers, bolting material, engagement, and project assembly requirements. The listed bolt details apply to the flange reference shown on this page.
Can the DWG be used for fabrication?
The DWG is useful for drafting, layout coordination, and reference. Fabrication should proceed only after the drawing, dimension data, material specification, pipe schedule, weld details, and project requirements have been reviewed.
What should be checked before installation?
Confirm the flange dimensions, bore, pipe compatibility, gasket, bolting, facing, material specification, and applicable pressure-temperature requirements. Also verify that the latest project documents and applicable standard requirements are being used.