Reducing Bronze Flanges Manufacturer & Exporter
A reducing flange joins a larger flange pattern to a smaller pipe or port. The face and drilling follow the larger nominal size; the bore or thread follows the smaller.
Product Overview
Reducing flanges remove the need for a separate reducer in a joint. A piece of equipment with a NPS 4 flanged connection can be piped in NPS 2 without adding a fitting: the flange mates with the NPS 4 face and takes the NPS 2 pipe in its bore. The result is a shorter assembly with fewer joints.
Product specification
SM-PRD-RED| Parameter | Specification |
|---|---|
| Product | Bronze reducing flange |
| Materials | UNS C93200, C95400, C95500, C95800, C63000, C83600, C84400 |
| Sizes | Flange size × connection size, e.g. NPS 4 × NPS 2 |
| Connection style | Slip-on, threaded or socket |
| Dimensional basis | Applicable standard or customer drawing |
| Pressure class | Class of the larger face, subject to connection limits |
| Facing | FF / RF / custom |
| Marking | Both sizes plus MSS SP-25 pattern or customer requirement |
| Documentation | MTC and inspection documents as applicable |
Technical Description
The flange is specified by two sizes: the flange size (face and drilling) and the connection size (bore, socket or thread). As the reduction increases, the hub and wall around the bore change, so the metal thickness around the bore is checked in the design. Reducing flanges can be made in the slip-on, threaded or socket-weld style.
Construction
- Face and bolt pattern for the larger nominal size
- Bore, socket or thread for the smaller nominal size
- Hub proportioned for the reduced connection
- Flat or raised face; class per drawing
- Marking shows both sizes
Available Materials
Available materials
SM-MAT-RED| Grade | Alloy | Stock and specification | Fit for this flange |
|---|---|---|---|
| UNS C93200 | Leaded tin bronze (SAE 660) | Cast: ASTM B584 / B271 / B505 | Free-machining alloy for tapped or bored reductions |
| UNS C95400 | Aluminium bronze | Cast: ASTM B148 / B271 / B505 | Pump and marine connections needing higher strength |
| UNS C95500 | Nickel aluminium bronze | Cast: ASTM B148 / B271 / B505 | Heavier-duty reductions |
| UNS C95800 | Nickel aluminium bronze (NAB) | Cast: ASTM B148 / B271 / B505 | Seawater service connections |
| UNS C63000 | Wrought nickel aluminium bronze | Bar, forging, plate: ASTM B150 / B124 / B283 / B171 | Wrought bar stock alternative |
| UNS C83600 | Leaded red brass / gunmetal | Cast: ASTM B62 / B584 | Water and valve-side reducing flanges |
| UNS C84400 | Leaded semi-red brass | Cast: ASTM B584 | Valve-composition service |
Stock form and the governing specification depend on grade and size. Mechanical properties are in the data page for each grade.
Dimensions and Sizes
Both sizes must be given. The parameters below define the part; hub dimensions are set by the standard or drawing for the chosen connection style.
Dimensions to confirm
SM-DIM-RED| Dimension | Basis |
|---|---|
| Flange size and class | Face and drilling, e.g. NPS 4 Class 150 |
| Connection size | Bore, socket or thread, e.g. NPS 2 |
| Connection style | Slip-on, threaded (NPT/BSPT) or socket |
| Hub OD and length | Per standard or drawing |
| Bolt circle (PCD) | Class pattern of the larger size |
| Face | FF / RF; finish per MSS SP-6 or customer |
Sizes
Given as flange size by connection size, for example NPS 4 × NPS 2. Include class and connection style.
Pressure Classes
Reducing flanges carry the class of the larger flange face, but the usable pressure is limited by the connection style and the wall around the reduced bore. Confirm the class and the connection with the piping specification.
Facing Options
Flat-face and raised-face options follow the larger flange size. Contact finish per MSS SP-6 or customer roughness.
Applications
- Pump and valve nozzle adaptation
- Equipment connections to smaller lines
- Header branches with reduced take-offs
- Retrofits where the nozzle size is fixed
Manufacturing
Blanks are bored, tapped or socketed to the connection size, then turned and drilled to the larger flange pattern.
Inspection and Documentation
Both sizes are verified: face and drilling against the flange standard or drawing, and bore, socket or thread against the connection. Material verification and MTC are provided as required.
Custom Requirements
Eccentric bores, non-standard reductions, special hub lengths, combined thread and socket, and customer marking.
Reducing Flanges: common questions
What is a reducing flange?
A reducing flange has the face and bolt pattern of a larger nominal size and a bore, thread or socket for a smaller pipe. It removes the need for a separate reducer.
How should I specify the size?
Give both sizes, for example NPS 4 by NPS 2, with the class and connection style (slip-on, threaded or socket).
Does the reduction change the pressure rating?
The class follows the larger face, but usable pressure is limited by the connection style and the wall around the reduced bore. Confirm it against your piping specification.
Related Information
Have a Drawing or Flange Specification?
Send your drawing, material grade, dimensions and quantity to our technical sales team.