Copper Alloy C85900-M04
Finish state
UNS C85900 · ASTM B584
M04 = as pressure die cast
High-volume thin-wall hardware and fittings; highest strength but lowest ductility and possible porosity in thick sections.
Values for the M04 condition
Other C85900 tempers and conditions
C85900 is listed in 5 conditions; see the grade overview at C85900.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
M01Default As sand cast | Standard general-purpose condition for valve bodies, fittings and ornamental castings in small to medium lots. | 115 | 290 | 25 | 60 HB | 26 % IACS |
As centrifugally cast | Choose for bushings, sleeves and rings where a denser, more sound wall than sand casting is needed. | 125 | 310 | 25 | 65 HB | 26 % IACS |
As plaster cast | Medium-volume parts needing better surface finish, closer tolerance and a finer grain than sand casting. | 130 | 320 | 22 | 68 HB | 26 % IACS |
As continuous cast | Bar, tube and hollow stock for machined parts — sound, uniform structure with best machining consistency. | 130 | 315 | 22 | 68 HB | 26 % IACS |
M04This page As pressure die cast | High-volume thin-wall hardware and fittings; highest strength but lowest ductility and possible porosity in thick sections. | 195 | 370 | 15 | 85 HB | 25 % IACS |
What is C85900-M04?
C85900-M04 is C85900 supplied in the M04 condition — high-volume thin-wall hardware and fittings; highest strength but lowest ductility and possible porosity in thick sections. C85900-M04 has a yield strength of 195 MPa (28.3 ksi) and a tensile strength of 370 MPa (53.7 ksi) — weaker than 56% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 100 GPa (14.5 Msi). C85900-M04 has a density of 8.4 g/cm³ (0.303 lb/in³), lighter than 75% of copper alloy grades. It melts at 875°C (1,607 °F). M01 is the default condition FabDigit quotes; M04 is available on request or by drawing note.
Advantages
- Low embodied carbon — 3.2 kg CO₂/kg, better than 92% of copper alloy grades
- Easy to machine — 75/100, better than 80% of copper alloy grades
Limitations
- Needs corrosion protection — 45/100, worse than 98% of copper alloy grades
- Limited formability — 8/100, worse than 94% of copper alloy grades
- Difficult to weld — 20/100, worse than 88% of copper alloy grades
- Low stiffness — 100 GPa (14.5 Msi), worse than 82% of copper alloy grades
C85900-M04 properties
Typical room-temperature values for C85900-M04; 19 are specific to this condition. Other listed values are C85900 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C85900-M04 has a density of 8.4 g/cm³ (0.303 lb/in³), lighter than 75% of copper alloy grades. It melts at 875°C (1,607 °F).
Mechanical12
C85900-M04 has a yield strength of 195 MPa (28.3 ksi) and a tensile strength of 370 MPa (53.7 ksi) — weaker than 56% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 100 GPa (14.5 Msi).
Thermal6
C85900-M04 is rated for continuous service to 200°C (392 °F). It conducts heat at 83 W/m·K (48 BTU/hr·ft·°F), better than 50% of copper alloy grades. Thermal expansion is 21 µm/m·K (11.7 µin/in·°F).
Electrical3
C85900-M04 conducts electricity at 25 % IACS, better than 59% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 98% of copper alloy grades.
Sustainability4
Producing a kilogram of C85900-M04 takes about 45 MJ of energy and emits 3.2 kg of CO₂ — less than 97% of copper alloy grades. Typical recycled content is 90%.
Manufacturability8
C85900-M04's machinability is very good (75/100, better than 80% of copper alloy grades); weldability poor (20/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C85900-M04
Is C85900 easy to machine?
Free-cutting behaviour with sharp positive-rake carbide or HSS tooling, high speeds, light feeds and chip-breaking geometry; little coolant needed.
Can C85900 be welded?
Fusion welding is not recommended (zinc volatilisation, lead hot cracking) — join by brazing or soft soldering, and use local exhaust for Zn fume.
Can C85900 be formed, bent or molded?
Cast only, not a wrought alloy: excellent fluidity, feed with adequate risers, degas the melt and control Zn loss; typical pour 1000–1060 °C.
What surface finishes work on C85900?
Buffs to a bright yellow finish, takes Ni/Cr and clear lacquer well; passivate with benzotriazole or chromate to slow tarnish. Anodizing is not applicable.
C85900 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 |
|---|---|---|
| Cuyellow brass casting range; confirm against the current CDA/UNS registration sheet | 58 – 64 | 61 |
| Sn | 0.2 – 1.5 | 0.8 |
| Pbmachinability addition; low-lead pours are made to plumbing rules | 0.5 – 1.5 | 1 |
| Fe | ≤ 0.7 | 0.2 |
| Al | ≤ 0.8 | 0.2 |
| Ni | ≤ 1 | — |
| Mn | ≤ 0.5 | — |
| Znremainder, nominally 33–40 % | balance | — |
C85900-M04 — frequently asked
What is C85900-M04 used for?
C85900-M04 is typically used for general hardware castings, decorative fittings and plumbing components. In short: free-cutting general castings; balanced strength and ductility; casting alloy only.
What is the yield strength of C85900-M04?
C85900-M04 has a typical yield strength of 195 MPa (28.3 ksi) and a tensile strength of 370 MPa (53.7 ksi) — weaker than 56% of copper alloy grades. Strength varies by condition: see the 5 listed tempers.
Is C85900-M04 easy to machine?
Yes — machinability is rated very good (75/100, better than 80% of copper alloy grades). Free-cutting behaviour with sharp positive-rake carbide or HSS tooling, high speeds, light feeds and chip-breaking geometry; little coolant needed.
Can C85900-M04 be welded?
Not readily — weldability is rated poor (20/100). Fusion welding is not recommended (zinc volatilisation, lead hot cracking) — join by brazing or soft soldering, and use local exhaust for Zn fume.
What surface finishes work on C85900-M04?
Buffs to a bright yellow finish, takes Ni/Cr and clear lacquer well; passivate with benzotriazole or chromate to slow tarnish. Anodizing is not applicable.
Can C85900-M04 be formed, bent or molded?
Cast only, not a wrought alloy: excellent fluidity, feed with adequate risers, degas the melt and control Zn loss; typical pour 1000–1060 °C.
What is the maximum service temperature of C85900-M04?
C85900-M04 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C85900-M01 and C85900-M04?
M01 is the default condition — standard general-purpose condition for valve bodies, fittings and ornamental castings in small to medium lots. M04: high-volume thin-wall hardware and fittings; highest strength but lowest ductility and possible porosity in thick sections. Yield strength is 115 MPa in M01 versus 195 MPa in M04.
Sources
- ASTM B584 — Copper Alloy Sand Castings for General Applications — ASTM International (2022)
- ASTM B176 — Copper-Alloy Die Castings — ASTM International (2018)
- CDA Standard Designations / Alloy Datasheets for Cast Yellow 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.