Threaded / Screwed Bronze Flanges Manufacturer & Exporter
Threaded flanges connect to pipe through an internal taper thread, so no welding or brazing is needed at the joint. They suit small-bore copper-alloy and mixed-metal piping that may need to be taken apart.
Product Overview
The threaded flange is the practical choice where hot work is restricted or where the line is expected to be dismantled for maintenance. The pipe screws into the tapped bore, and the flange face then mates with a counter-flange or valve end in the usual way. It is common on pump skids, valve manifolds, instrument lines and water systems.
Product specification
SM-PRD-THR| Parameter | Specification |
|---|---|
| Product | Bronze threaded (screwed) flange |
| Materials | UNS C93200, C95400, C95500, C95800, C63000, C83600, C84400 |
| Thread | NPT (ASME B1.20.1) or BSPT / ISO 7-1, as specified |
| Dimensional basis | Applicable standard or customer drawing |
| Pressure class | Class 150 / 300 or per drawing, as applicable |
| Facing | FF / RF / custom |
| Joint to pipe | Threaded; sealant or seal weld per piping specification |
| Marking | MSS SP-25 pattern or customer requirement |
| Documentation | MTC and inspection documents as applicable |
Technical Description
The bore is tapped with an internal pipe thread — normally NPT to ASME B1.20.1 in U.S. practice, or BSPT (ISO 7-1) where the system calls for it. Thread form, tolerance and gauging are defined at order. A threaded joint relies on thread engagement and sealant or seal weld for tightness, and is generally kept away from severe cyclic or thermal-shock service. Suitability for the duty remains the piping designer’s decision.
Construction
- Tapped bore: NPT (ASME B1.20.1) or BSPT / ISO 7-1, as specified
- Hubbed or flat profile; flat face or raised face
- Drilling to the specified class pattern or drawing
- Thread lead-in chamfer to ease engagement
- Face counterbore or seal-weld preparation on request
Available Materials
Available materials
SM-MAT-THR| Grade | Alloy | Stock and specification | Fit for this flange |
|---|---|---|---|
| UNS C93200 | Leaded tin bronze (SAE 660) | Cast: ASTM B584 / B271 / B505 | Free-machining leaded bronze; clean thread cutting |
| UNS C95400 | Aluminium bronze | Cast: ASTM B148 / B271 / B505 | Higher strength and wear resistance; lower machinability rating than leaded bronzes |
| UNS C95500 | Nickel aluminium bronze | Cast: ASTM B148 / B271 / B505 | Heavier-duty threaded connections |
| UNS C95800 | Nickel aluminium bronze (NAB) | Cast: ASTM B148 / B271 / B505 | Marine and seawater service in smaller bores |
| UNS C63000 | Wrought nickel aluminium bronze | Bar, forging, plate: ASTM B150 / B124 / B283 / B171 | Wrought bar stock where cast product is not accepted |
| UNS C83600 | Leaded red brass / gunmetal | Cast: ASTM B62 / B584 | Common water, valve and general-service alloy for tapped flanges |
| UNS C84400 | Leaded semi-red brass | Cast: ASTM B584 | Valve-composition alloy for threaded connections |
Stock form and the governing specification depend on grade and size. Mechanical properties are in the data page for each grade.
Dimensions and Sizes
Dimensions to confirm in the RFQ are listed below. The flange bolt pattern follows the same class tables used for other flange types; thread dimensions and hub proportions vary by standard, so we work from the standard or drawing you name.
Dimensions to confirm
SM-DIM-THR| Dimension | Basis |
|---|---|
| Flange OD and thickness | Standard class table or drawing |
| Thread size and form | NPS and NPT / BSPT, with length of engagement |
| Hub OD and length | Per standard or drawing |
| Bolt circle (PCD) | Class pattern or drawing |
| Bolt holes | Count and diameter per class or drawing |
| Face | FF / RF; finish per MSS SP-6 or customer |
Sizes
Threaded flanges are typically supplied in small to medium nominal sizes; the practical range depends on the standard and alloy. State NPS, thread type and class in the RFQ.
Pressure Classes
Class 150 and Class 300 patterns are typical for threaded copper-alloy flanges. Because the thread carries the load instead of a weld, the allowable pressure and temperature depend on the alloy, thread engagement and the governing standard. Pressure testing is done only when specified on the purchase order.
Facing Options
Flat-face and raised-face options are available. Where a gasket seats on the face, the contact finish is machined to MSS SP-6 or your stated roughness.
Applications
- Pump and valve connections on skids
- Water and utility lines
- Instrument and sampling branches
- Maintenance-friendly seawater branches in small bore
Manufacturing
Blanks come from cast or wrought stock depending on grade and specification. Machining covers boring, tapping, facing, OD and hub turning, and drilling the bolt circle. Thread tapping is carried out on the finished bore so the thread runs true to the face.
Inspection and Documentation
Dimensional and visual inspection is standard. Thread gauging to ASME B1.20.1 (or the thread standard you name) is performed where required. Material verification and MTC are provided as specified, and extra tests are carried out only when listed on the purchase order.
Custom Requirements
Metric or BSP threads, reduced thread sizes, seal-weld preparation, special drilling, tapped bolt holes and customer marking can be machined to drawing.
Threaded / Screwed Flanges: common questions
Which thread types are available on threaded bronze flanges?
NPT to ASME B1.20.1 and BSPT to ISO 7-1 are the usual forms. Other threads can be machined to your drawing.
Are threaded flanges suitable for high-pressure or cyclic service?
A threaded joint relies on thread engagement and sealant or a seal weld, so it is generally kept away from severe cyclic or thermal-shock service. The piping designer decides whether it suits the duty.
Which grades are common for threaded flanges?
C83600, C84400 and C93200 are common for water, valve and general service because they machine cleanly. C95400 and C95800 are used where higher strength or marine service is required.
Related Information
Have a Drawing or Flange Specification?
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