Copper Alloy C99750
UNS C99750 · ASTM B584, B763
C99750 is a leaded manganese white brass casting alloy to ASTM B584 and B763, with 0.5-2.5% Pb added for chip breaking and aluminium and manganese for strength.
Reference datasheet — C99750 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the M-AC condition
C99750 tempers and conditions
C99750 is supplied in 3 conditions, soft to hard. M-AC is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
M-ACDefault As Cast | Standard stocked condition for decorative and general-purpose C99750 castings; best ductility and easiest machining. | 234 | 455 | 25 | 130 HB | 3.5 % IACS |
As continuous cast | Pick for machined bushings, sleeves and wear rings — denser, finer structure than sand cast with slightly higher strength and hardness. | 280 | 490 | 18 | 145 HB | 4 % IACS |
Solution heat treated and precipitation hardened | Choose when castings must carry higher loads or resist wear — roughly 35–40 % strength gain at the cost of ductility and machinability. | 415 | 620 | 10 | 200 HB | 4.5 % IACS |
What is C99750?
C99750 is a leaded manganese white brass casting alloy to ASTM B584 and B763, with 0.5-2.5% Pb added for chip breaking and aluminium and manganese for strength. Default as-cast values are 455 MPa tensile, 234 MPa yield, 25% elongation, 130 HB (74 HRB), density 7.78 g/cm3, 100 GPa modulus, melting point 871 °C and service to 250 °C. Thermal conductivity is 25 W/m-K and electrical conductivity 3.5% IACS, so it is not a conductor alloy; corrosion resistance scores 62 and weldability only 45. Machinability of 35 is better than unleaded C99700 but well below leaded yellow brasses such as ZCuZn40Pb2. C99750 has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 89% of copper alloy grades. It melts at 871°C (1,600 °F). C99750 has a yield strength of 234 MPa (33.9 ksi) and a tensile strength of 455 MPa (66 ksi) — stronger than 51% of copper alloy grades. Elongation at break is 25% and the elastic modulus is 100 GPa (14.5 Msi).
What is C99750 used for?
- decorative hardware
- marine deck fittings
- architectural castings
Advantages
- Low embodied carbon — 3.2 kg CO₂/kg, better than 92% of copper alloy grades
Limitations
- Low electrical conductivity — 3.5 % IACS, worse than 99% of copper alloy grades
- Poor heat conductor — 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 98% of copper alloy grades
- Low stiffness — 100 GPa (14.5 Msi), worse than 82% of copper alloy grades
C99750 properties
Typical room-temperature values for C99750-M-AC; bars are the position among copper alloy grades.
Physical3
C99750 has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 89% of copper alloy grades. It melts at 871°C (1,600 °F).
Mechanical12
C99750 has a yield strength of 234 MPa (33.9 ksi) and a tensile strength of 455 MPa (66 ksi) — stronger than 51% of copper alloy grades. Elongation at break is 25% and the elastic modulus is 100 GPa (14.5 Msi).
Thermal6
C99750 is rated for continuous service to 250°C (482 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 98% of copper alloy grades. Thermal expansion is 20 µm/m·K (11.1 µin/in·°F).
Electrical3
C99750 conducts electricity at 3.5 % IACS, worse than 99% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C99750 takes about 45 MJ of energy and emits 3.2 kg of CO₂ — less than 97% of copper alloy grades. Typical recycled content is 70%.
Manufacturability8
C99750's machinability is fair (35/100, better than 51% of copper alloy grades); weldability fair (45/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C99750 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C99750
Is C99750 easy to machine?
Free-machining thanks to 0.5–2.5 % Pb — use sharp carbide tooling, moderate speeds and generous coolant; high-Mn matrix work-hardens if tools rub.
Can C99750 be welded?
Fusion welding is difficult (Al oxide film, Pb hot-cracking, Zn fumes); use GTAW with Al-bronze filler and preheat only for repair, or braze/mechanically fasten instead.
Can C99750 be formed, bent or molded?
Casting alloy with good fluidity — sand, permanent-mould, centrifugal and continuous casting all practical; degas melt, control Mn losses and feed heavy sections to avoid shrinkage porosity.
C99750 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cu | 55 – 61 | 58 |
| Mnprimary strengthener, gives white colour | 17 – 23 | 20 |
| Al | 0.5 – 2.5 | 1.5 |
| Pbfree-machining addition | 0.5 – 2.5 | 1.5 |
| NiNi + Co | ≤ 5 | 1 |
| Fe | ≤ 1 | 0.4 |
| Znremainder, typically 17–23 % | balance |
What surface finishes work on C99750?
Polishes to a bright silvery-white finish that needs no plating for decorative use; accepts nickel/chrome plating and clear lacquer, but not anodising.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Equivalent designations
Standards and trade names that resolve to Copper Alloy C99750 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B584B763
How much does C99750 cost?
C99750 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C99750 — frequently asked
What is C99750 used for?
C99750 is typically used for decorative hardware, marine deck fittings and architectural castings. In short: machinable white brass; higher strength than C99700; service to 250 °C.
What is the yield strength of C99750?
C99750 has a typical yield strength of 234 MPa (33.9 ksi) and a tensile strength of 455 MPa (66 ksi) — stronger than 51% of copper alloy grades. Strength varies by condition: see the 3 listed tempers.
Is C99750 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of copper alloy grades). Free-machining thanks to 0.5–2.5 % Pb — use sharp carbide tooling, moderate speeds and generous coolant; high-Mn matrix work-hardens if tools rub.
Can C99750 be welded?
With care — weldability is rated fair (45/100). Fusion welding is difficult (Al oxide film, Pb hot-cracking, Zn fumes); use GTAW with Al-bronze filler and preheat only for repair, or braze/mechanically fasten instead.
What surface finishes work on C99750?
Polishes to a bright silvery-white finish that needs no plating for decorative use; accepts nickel/chrome plating and clear lacquer, but not anodising.
Can C99750 be formed, bent or molded?
Casting alloy with good fluidity — sand, permanent-mould, centrifugal and continuous casting all practical; degas melt, control Mn losses and feed heavy sections to avoid shrinkage porosity.
What is the maximum service temperature of C99750?
C99750 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C99750 M-AC and C99750-TF00?
M-AC is the default condition — standard stocked condition for decorative and general-purpose C99750 castings; best ductility and easiest machining. TF00: choose when castings must carry higher loads or resist wear — roughly 35–40 % strength gain at the cost of ductility and machinability. Yield strength is 234 MPa in M-AC versus 415 MPa in TF00.
How much does C99750 cost?
C99750 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B584 — Copper Alloy Sand Castings for General Applications — ASTM International (2022)
- ASTM B763 — Copper Alloy Sand Castings for Valve Applications — ASTM International (2020)
- CDA/UNS Copper Alloy Datasheets (C997xx white manganese brasses) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.