Copper Alloy C90900-M02
Heat-treated state
UNS C90900
M02 = as centrifugally cast
Choose for dense, porosity-free bushings, sleeves and gear rims of rotational shape.
Values for the M02 condition
Other C90900 tempers and conditions
C90900 is listed in 4 conditions; see the grade overview at C90900.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
M01Default As sand cast | Standard stocked condition for gear blanks, worm wheels and bushings poured in sand moulds. | 152 | 275 | 5 | 80 HB | 10.5 % IACS |
As plaster cast | Use for repeat-run small parts where a chilled, finer structure and better surface are wanted. | 165 | 295 | 5 | 88 HB | 10.5 % IACS |
M02This page As centrifugally cast | Choose for dense, porosity-free bushings, sleeves and gear rims of rotational shape. | 170 | 305 | 6 | 90 HB | 10.5 % IACS |
As continuous cast | Best choice for stock bar and tube: highest density and hardness, minimal machining allowance. | 180 | 310 | 6 | 95 HB | 10.5 % IACS |
What is C90900-M02?
C90900-M02 is C90900 heat treated to M02 — choose for dense, porosity-free bushings, sleeves and gear rims of rotational shape. C90900-M02 has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 305 MPa (44.2 ksi) — weaker than 62% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 105 GPa (15.2 Msi). C90900-M02 has a density of 8.79 g/cm³ (0.318 lb/in³), heavier than 54% of copper alloy grades. It melts at 830°C (1,526 °F). M01 is the default condition FabDigit quotes; M02 is available on request or by drawing note.
Advantages
- High service temperature — 260°C (500 °F), better than 75% of copper alloy grades
Limitations
- Limited formability — 5/100, worse than 98% of copper alloy grades
- Limited ductility — 6%, worse than 89% of copper alloy grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 89% of copper alloy grades
- Hard to polish — 65/100, worse than 87% of copper alloy grades
- Difficult to weld — 22/100, worse than 83% of copper alloy grades
C90900-M02 properties
Typical room-temperature values for C90900-M02; 21 are specific to this condition. Other listed values are C90900 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C90900-M02 has a density of 8.79 g/cm³ (0.318 lb/in³), heavier than 54% of copper alloy grades. It melts at 830°C (1,526 °F).
Mechanical15
C90900-M02 has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 305 MPa (44.2 ksi) — weaker than 62% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
C90900-M02 is rated for continuous service to 260°C (500 °F). It conducts heat at 71 W/m·K (41 BTU/hr·ft·°F), worse than 54% of copper alloy grades. Thermal expansion is 18.4 µm/m·K (10.2 µin/in·°F).
Electrical3
C90900-M02 conducts electricity at 10.5 % IACS, worse than 72% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (63/100), better than 52% of copper alloy grades.
Sustainability4
Producing a kilogram of C90900-M02 takes about 85 MJ of energy and emits 5.5 kg of CO₂ — more than 92% of copper alloy grades. Typical recycled content is 65%.
Manufacturability8
C90900-M02's machinability is poor (32/100, worse than 57% of copper alloy grades); weldability poor (22/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C90900-M02
Is C90900 easy to machine?
Machines to a short, brittle chip at ~30 % of free-cutting brass; use sharp positive-rake carbide, moderate speeds and rigid setups to avoid chipping the hard delta phase.
Can C90900 be welded?
Poor arc/gas weldability — hot-short and crack prone; repair by low-heat brazing or preheated GTAW with matching tin-bronze filler, then stress relieve.
Can C90900 be formed, bent or molded?
Cast only, not workable cold; wide freezing range requires chills, generous risers and directional solidification to avoid tin sweat and interdendritic shrinkage.
What surface finishes work on C90900?
Takes a fine polish and bronze patina; can be tin-, nickel- or chrome-plated after copper strike, and is easily soft-soldered.
C90900 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 |
|---|---|---|
| Sn | 12 – 14 | 13 |
| Pb | ≤ 0.25 | — |
| Zn | ≤ 0.25 | — |
| Fe | ≤ 0.15 | — |
| Niincl. Co | ≤ 0.5 | — |
| Sb | ≤ 0.2 | — |
| S | ≤ 0.05 | — |
| P | ≤ 0.05 | — |
| Al | ≤ 0.01 | — |
| Si | ≤ 0.01 | — |
| CuCu + named elements = 99.4 % min | ≥ 85 (balance) | — |
C90900-M02 — frequently asked
What is C90900-M02 used for?
C90900-M02 is typically used for gears, worm wheels and bushings. In short: hard, wear-resistant tin bronze; light-duty gear castings; low elongation, cast only.
What is the yield strength of C90900-M02?
C90900-M02 has a typical yield strength of 170 MPa (24.7 ksi) and a tensile strength of 305 MPa (44.2 ksi) — weaker than 62% of copper alloy grades. Strength varies by condition: see the 4 listed tempers.
Is C90900-M02 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 57% of copper alloy grades). Machines to a short, brittle chip at ~30 % of free-cutting brass; use sharp positive-rake carbide, moderate speeds and rigid setups to avoid chipping the hard delta phase.
Can C90900-M02 be welded?
Not readily — weldability is rated poor (22/100). Poor arc/gas weldability — hot-short and crack prone; repair by low-heat brazing or preheated GTAW with matching tin-bronze filler, then stress relieve.
What surface finishes work on C90900-M02?
Takes a fine polish and bronze patina; can be tin-, nickel- or chrome-plated after copper strike, and is easily soft-soldered.
Can C90900-M02 be formed, bent or molded?
Cast only, not workable cold; wide freezing range requires chills, generous risers and directional solidification to avoid tin sweat and interdendritic shrinkage.
What is the maximum service temperature of C90900-M02?
C90900-M02 is rated for continuous use to about 260°C (500 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C90900-M01 and C90900-M07?
M01 is the default condition — standard stocked condition for gear blanks, worm wheels and bushings poured in sand moulds. M07: best choice for stock bar and tube: highest density and hardness, minimal machining allowance. Yield strength is 152 MPa in M01 versus 180 MPa in M07.
Sources
- ASTM B427 — Gear Bronze Alloy Castings — ASTM International (2020)
- ASTM B505/B505M — Continuous Cast Copper Alloy Castings — ASTM International (2018)
- CDA Alloy Datasheet C90900 — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.