This reference page provides the dimensional data, connection details, and CAD resource for a Weld Neck Flange 1 1/4 Inch Class 600. Use the source values for drafting and preliminary coordination, then verify the final selection against the project specification and applicable piping requirements.
For related design work, compare this page with references covering pipe schedules, flange facing types, stud bolts, gaskets, and piping isometric drawings. These topics help explain how flange dimensions interface with the pipe, bolting, sealing, and fabrication details.
Weld Neck Flange 1 1/4″ Class 600
Weld Neck Flange 1 1/4″ 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 1 1/4″ Class 600 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):1 1/4″
- DN Size: DN32
- Outside Diameter:133mm
- Flange Thickness:20.6mm
- Hub Diameter:64mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:63.5mm
- Weight: 2.3kg
- Number of Bolts:4
- Stud Bolt Size: 5/8″ UNC (or M16) x 95 Long
- Hole Diameter: 3/4″ (19.05mm)
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 1 1/4″ 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 1 1/4″ 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 Read This Flange Reference
The dimension list identifies the flange envelope, hub geometry, raised-face detail, bolt arrangement, hole size, and listed weight. The outside diameter and thickness are useful for layout and clearance checks, while the hub dimensions support welding and connection detailing.
The bore is not a single universal value in this reference because it depends on the pipe schedule and wall thickness. Confirm the selected pipe before preparing a fabrication drawing or matching the flange to a pipe spool. A flange that fits the nominal pipe size still requires a bore and weld-end check.
Class, Facing, and Bolting
Class 600 identifies the flange pressure class within the referenced flange standard; it should not be treated as a standalone allowable pressure for every temperature, material, or service condition. Final pressure-temperature suitability depends on the applicable material specification, design conditions, gasket, facing, and project requirements.
Check the listed stud bolt size, length, hole diameter, and bolt count together. Bolt selection also depends on flange thickness, gasket arrangement, washers where specified, and the required assembly procedure. Do not substitute metric or inch hardware without confirming dimensional and specification compatibility.
Using the CAD File
The downloadable DWG can support piping layout, equipment coordination, drafting, and fabrication reference. Before incorporating it into a controlled drawing, confirm units, drawing scale, layer conventions, flange facing, bore condition, and revision status. CAD geometry is a coordination aid and does not replace the source dimension list or an engineering review.
Selection and Verification Checklist
- Match the nominal pipe size and selected pipe schedule.
- Confirm the bore and weld-end geometry before fabrication.
- Verify the flange material and project pressure-temperature requirements.
- Coordinate the raised face, gasket, studs, nuts, and tightening procedure.
- Check clearances for bolt installation, welding, insulation, and maintenance.
- Use the related Class 600 size pages when comparing alternatives within the same flange series.
Frequently Asked Questions
What does a weld neck flange do?
A weld neck flange connects to the pipe through a butt weld at its tapered hub. The gradual hub profile helps transition loads from the flange into the pipe and is commonly considered where strength and resistance to cyclic loading are important.
Does the listed bore apply to every pipe schedule?
No. The source identifies the bore as dependent on pipe schedule and wall thickness. Confirm the actual pipe before ordering, welding, or finalizing a drawing.
Is Class 600 the same as a fixed allowable pressure?
No. The class designation must be evaluated with material, temperature, gasket, facing, and the governing project or piping requirements. Engineering verification is required for the final service condition.
Can the DWG be used for fabrication?
The DWG is useful as a drafting and coordination reference. Verify its dimensions, units, bore condition, revision, and project requirements before using it for fabrication or issuing a controlled drawing.
What should be checked before installing this flange?
Confirm the pipe size and schedule, bore, flange material, facing, gasket, bolt compatibility, bolt length, alignment, welding details, and applicable inspection requirements.