Copper Alloy C99700-M02
Heat-treated state
UNS C99700 · ASTM B584, B763
M02 = as centrifugally cast
Chill-cast condition giving finer grain, higher strength and hardness for repeat-production hardware.
Values for the M02 condition
Other C99700 tempers and conditions
C99700 is listed in 7 conditions; see the grade overview at C99700.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress-relief annealed casting | Low-temperature (about 300–350 °C) stress relief for parts that will be heavily machined or exposed to ammonia-bearing atmospheres. | 210 | 435 | 28 | 115 HB | 3 % IACS |
M01Default As sand cast | Standard ASTM B584 sand-cast condition for architectural and marine hardware of medium size. | 230 | 450 | 25 | 125 HB | 3 % IACS |
As chill cast | Pick for thin, intricate decorative parts to ASTM B763 where as-cast surface must be near-final before polishing. | 235 | 450 | 22 | 130 HB | 3 % IACS |
As pressure die cast | For rings, sleeves and bushings needing dense, porosity-free sections. | 250 | 470 | 22 | 135 HB | 3 % IACS |
As plaster cast | Continuous-cast bar/tube stock for machined decorative components; most uniform structure of the cast forms. | 260 | 480 | 20 | 140 HB | 3 % IACS |
M02This page As centrifugally cast | Chill-cast condition giving finer grain, higher strength and hardness for repeat-production hardware. | 275 | 485 | 20 | 145 HB | 3 % IACS |
As continuous cast | High-volume small decorative hardware; highest as-cast strength but limited section size and die life. | 290 | 500 | 15 | 150 HB | 3 % IACS |
What is C99700-M02?
C99700-M02 is C99700 heat treated to M02 — chill-cast condition giving finer grain, higher strength and hardness for repeat-production hardware. C99700-M02 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 485 MPa (70.3 ksi) — stronger than 57% of copper alloy grades. Elongation at break is 20% and the elastic modulus is 105 GPa (15.2 Msi). C99700-M02 has a density of 8.03 g/cm³ (0.29 lb/in³), lighter than 87% of copper alloy grades. It melts at 880°C (1,616 °F). M01 is the default condition FabDigit quotes; M02 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 88/100, better than 97% of copper alloy grades
Limitations
- Low electrical conductivity — 3 % IACS, worse than 100% of copper alloy grades
- Poor heat conductor — 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 97% of copper alloy grades
- Limited formability — 15/100, worse than 79% of copper alloy grades
C99700-M02 properties
Typical room-temperature values for C99700-M02; 20 are specific to this condition. Other listed values are C99700 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C99700-M02 has a density of 8.03 g/cm³ (0.29 lb/in³), lighter than 87% of copper alloy grades. It melts at 880°C (1,616 °F).
Mechanical14
C99700-M02 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 485 MPa (70.3 ksi) — stronger than 57% of copper alloy grades. Elongation at break is 20% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
C99700-M02 is rated for continuous service to 230°C (446 °F). It conducts heat at 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 97% of copper alloy grades. Thermal expansion is 20 µm/m·K (11.1 µin/in·°F).
Electrical3
C99700-M02 conducts electricity at 3 % IACS, worse than 100% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 64% of copper alloy grades.
Sustainability4
Producing a kilogram of C99700-M02 takes about 55 MJ of energy and emits 3.8 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 75%.
Manufacturability8
C99700-M02's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability fair (35/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C99700-M02
Is C99700 easy to machine?
Tough, gummy chips — use sharp positive-rake carbide, moderate speed with generous coolant; rating ≈30 % of free-cutting brass.
Can C99700 be welded?
Best joined by brazing or silver soldering; GTAW possible with matching Cu-Mn filler but zinc fume, porosity and hot cracking must be controlled.
Can C99700 be formed, bent or molded?
Foundry alloy only — good fluidity, use chills and ample risering to avoid centreline shrinkage; degas and keep pouring temperature ~1050–1100 °C to limit Mn/Zn loss.
What surface finishes work on C99700?
Takes a bright silver-like mirror polish directly; can be brushed, satin-finished, PVD-coated or clear-lacquered — plating is usually unnecessary.
C99700 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 |
|---|---|---|
| Mn | 11 – 15 | 13 |
| Zn | 19 – 25 | 22 |
| NiNi + Co | 4 – 6 | 5 |
| Al | 0.5 – 3 | 1.5 |
| Fe | ≤ 1 | 0.4 |
| Pb | ≤ 2 | 0.5 |
| Cu54.0 % min per ASTM B584 | ≥ 54 (balance) | — |
C99700-M02 — frequently asked
What is C99700-M02 used for?
C99700-M02 is typically used for decorative hardware, architectural fittings, marine hardware and art castings. In short: silver-white without plating; strongest decorative cast brass; slow-machining copper alloy.
What is the yield strength of C99700-M02?
C99700-M02 has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 485 MPa (70.3 ksi) — stronger than 57% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C99700-M02 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Tough, gummy chips — use sharp positive-rake carbide, moderate speed with generous coolant; rating ≈30 % of free-cutting brass.
Can C99700-M02 be welded?
With care — weldability is rated fair (35/100). Best joined by brazing or silver soldering; GTAW possible with matching Cu-Mn filler but zinc fume, porosity and hot cracking must be controlled.
What surface finishes work on C99700-M02?
Takes a bright silver-like mirror polish directly; can be brushed, satin-finished, PVD-coated or clear-lacquered — plating is usually unnecessary.
Can C99700-M02 be formed, bent or molded?
Foundry alloy only — good fluidity, use chills and ample risering to avoid centreline shrinkage; degas and keep pouring temperature ~1050–1100 °C to limit Mn/Zn loss.
What is the maximum service temperature of C99700-M02?
C99700-M02 is rated for continuous use to about 230°C (446 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C99700-M01 and C99700-M07?
M01 is the default condition — standard ASTM B584 sand-cast condition for architectural and marine hardware of medium size. M07: high-volume small decorative hardware; highest as-cast strength but limited section size and die life. Yield strength is 230 MPa in M01 versus 290 MPa in M07.
Sources
- ASTM B584 — Standard Specification for Copper Alloy Sand Castings for General Applications — ASTM International (2022)
- ASTM B763 — Copper Alloy Sand Castings for Valve Applications / investment cast product data — ASTM International (2021)
- CDA Alloy Database — C99700 white manganese bronze — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials (copper alloys) — ASM International (2005)
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.