This reference page provides the listed dimensions and connection details for a Weld Neck Flange 1 1/4 Inch Class 150. Use it when checking flange selections, preparing piping layouts, or coordinating fabrication and CAD work.
The source data identifies the flange outside diameter, thickness, hub diameter, raised face, bolt arrangement, stud bolt details, hole diameter, and weight. Because the bore depends on the pipe schedule and wall thickness, it should be checked against the selected pipe rather than assumed from the nominal flange size alone.
Weld Neck Flange 1 1/4″ Class 150
Weld Neck Flange 1 1/4″ Class 150 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 1 1/4″ Class 150 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):1 1/4″
- DN Size: DN32
- Outside Diameter:117mm
- Flange Thickness:14.2mm
- Hub Diameter:59mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:63.5mm
- Weight: 1.4kg
- Number of Bolts:4
- Stud Bolt Size: 1/2″ UNC (or M14) x 70 Long
- Hole Diameter: 5/8″ (15.875mm)
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 150 is commonly used for:
- Process piping systems
- Oil and gas lines
- Water and utility piping
- High-temperature 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 150, which can be used for drafting, detailing, piping layout coordination, and fabrication reference.
Available Weld Neck Flange Class 150 Sizes
This size is part of the Weld Neck Flange Class 150 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 These Weld Neck Flange Dimensions
A weld neck flange is attached to the pipe through its tapered hub. In a drawing or model, the outside diameter and raised face diameter describe the flange face, while the hub diameter helps identify the transition from the flange body to the pipe connection.
The listed bore is intentionally described as variable. Pipe schedule and wall thickness affect the opening through the flange, so the bore should be coordinated with the actual pipe specification before fabrication. This is an important check when using flange dimensions alongside pipe schedule references or CAD blocks.
Bolting and Face Details
The bolt count, stud bolt size, and hole diameter describe separate parts of the bolted connection. The bolt holes must align with the mating flange, and the selected gasket and bolting arrangement should be reviewed together with the flange facing and project requirements.
Using the CAD Reference
The downloadable DWG can support drafting, piping layout coordination, detailing, and fabrication reference. Before issuing a drawing, verify the flange orientation, pipe connection, bore, facing arrangement, gasket requirements, and mating component against the project specification.
Related Reference Topics
- Pipe schedule and bore selection
- Flange facing and raised-face terminology
- Flange bolt patterns and stud bolt identification
- Class 150 flange dimensions
- Pipe fittings and CAD/DWG reference files
Frequently Asked Questions
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 intended to support a robust flange connection.
What does the Class 150 designation indicate?
Class 150 is the flange class designation used for this reference. It should not be treated as a standalone pressure value for every service condition; pressure-temperature limits, material, gasket, bolting, and project requirements must be checked together.
Why does the bore vary?
The bore depends on the pipe schedule and wall thickness selected for the connection. Confirming the pipe specification is therefore necessary before ordering, modeling, or fabricating the flange.
Can the DWG be used for fabrication?
The DWG is useful as a drafting and coordination reference. Fabrication should proceed only after the drawing, material requirements, bore, facing, bolting, gasket, and applicable project specifications have been verified.
Should this flange be checked against a mating flange?
Yes. Confirm that the mating flange has compatible dimensions, bolt-hole alignment, facing, gasket requirements, and service requirements before installation.