Bronze Flange Materials by UNS Grade
Seven cast and wrought copper alloys for flanges, with composition class, specification and service notes.
Seven grades side by side
Figures are specification minimums or ratings from published CDA / ASTM data and depend on product form and condition. Full tables are on each grade page.
Material comparison
SM-MAT-01| Grade | Alloy family | Specification | Tensile min., ksi | Machinability* | Typical flange service |
|---|---|---|---|---|---|
| UNS C93200 | High-leaded tin bronze (SAE 660) | ASTM B584 / B271 / B505 | 30 (B584, sand cast) | 70 | General purpose, bushing-type flanges |
| UNS C95400 | Aluminium bronze | ASTM B148 / B271 / B505 | 75 as-cast; 90 heat-treated | 60 | Pumps, valves, marine pipework |
| UNS C95500 | Nickel aluminium bronze | ASTM B148 / B271 / B505 | 90 as-cast | 50 | Heavy-duty marine and industrial |
| UNS C95800 | Nickel aluminium bronze (NAB) | ASTM B148 / B271 / B505 | 85 (B148) | 20 | Seawater, offshore, desalination |
| UNS C63000 | Wrought nickel aluminium bronze | ASTM B150 / B124 / B283 / B171 | ≈80 – 110 (temper, size) | 30 | Bar, forging and plate flanges |
| UNS C83600 | Leaded red brass / ounce metal | ASTM B62 / B584 | 30 (B62) | 84 | Valve, pump and water flanges |
| UNS C84400 | Leaded semi-red brass | ASTM B584 | Per B584 edition | 90 | Valves, fittings, plumbing |
*CDA machinability rating, free-cutting brass C36000 = 100. 1 ksi ≈ 6.9 MPa. C84400 minimums are set in the ASTM B584 edition named on the purchase order.
Choose a grade
Bronze
High-leaded tin bronze (SAE 660). Free-machining general-purpose alloy.
Material dataUNS C95400Aluminium Bronze
Cast aluminium bronze. Wear-resistant, heat-treatable, marine and pump service.
Material dataUNS C95500Aluminium Bronze
Nickel-bearing aluminium bronze. Higher strength for heavy-duty service.
Material dataUNS C95800Nickel Aluminium Bronze
Nickel aluminium bronze (NAB). The seawater, marine and offshore alloy.
Material dataUNS C63000Aluminium Bronze
Wrought nickel aluminium bronze for bar, forging and plate flanges.
Material dataUNS C83600Gunmetal
Ounce metal 85-5-5-5 to ASTM B62. Valve, pump and water flanges.
Material dataUNS C84400Bronze
Valve-composition semi-red brass. Fast machining for fittings and valves.
Material dataHow to choose between them
Seawater and offshore duty: nickel aluminium bronze, C95800 cast or C63000 wrought, with C95500 and C95400 for heavy-duty and general marine service.
Valves, pumps and general water service: C83600 and C84400 are long-established and machine well; C93200 adds bearing-type properties.
Potable water: leaded grades (C93200, C83600, C84400) are not used for drinking-water wetted parts under U.S. lead-free rules. Confirm lead content and approvals for your project.
Welding: aluminium bronzes are weldable by qualified procedure; leaded bronzes are brazed or soldered.
Not sure which grade fits?
Send the service conditions and drawing. We will check the grade against the flange type and specification.