Copper Alloy C81200-M05
Finish state
UNS C81200 · ASTM B824, B369
M05 = as plaster cast
Medium-volume parts; finer chill grain gives slightly higher strength and better surface than sand.
Values for the M05 condition
Other C81200 tempers and conditions
C81200 is listed in 6 conditions; see the grade overview at C81200.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Use after heavy weld repair or straightening to restore maximum conductivity and remove residual stress. | 55 | 165 | 45 | 40 HB | 84 % IACS |
M01Default As sand cast | Standard stocked/produced condition for one-off and small-lot electrical castings. | 62 | 172 | 40 | 44 HB | 80 % IACS |
As investment cast | Choose for thin, intricate contact/terminal shapes where machining allowance must be minimal. | 62 | 170 | 38 | 44 HB | 80 % IACS |
As centrifugally cast | Pick for rings, bushings and tubular electrical bodies needing dense, porosity-free walls. | 65 | 185 | 40 | 46 HB | 82 % IACS |
M05This page As plaster cast | Medium-volume parts; finer chill grain gives slightly higher strength and better surface than sand. | 68 | 185 | 38 | 48 HB | 80 % IACS |
As continuous cast | Best choice when buying bar/tube stock for machined electrical parts — densest, most uniform structure. | 75 | 200 | 35 | 50 HB | 82 % IACS |
What is C81200-M05?
C81200-M05 is C81200 supplied in the M05 condition — medium-volume parts; finer chill grain gives slightly higher strength and better surface than sand. C81200-M05 has a yield strength of 68 MPa (9.86 ksi) and a tensile strength of 185 MPa (26.8 ksi) — weaker than 97% of copper alloy grades. Elongation at break is 38% and the elastic modulus is 112 GPa (16.2 Msi). C81200-M05 has a density of 8.91 g/cm³ (0.322 lb/in³), heavier than 80% of copper alloy grades. It melts at 1,065°C (1,949 °F). M01 is the default condition FabDigit quotes; M05 is available on request or by drawing note.
Advantages
- Conducts heat well — 320 W/m·K (184.9 BTU/hr·ft·°F), better than 84% of copper alloy grades
- High electrical conductivity — 80 % IACS, better than 84% of copper alloy grades
- Ductile — tolerates forming and impact — 38%, better than 82% of copper alloy grades
- Readily welded — 65/100, better than 80% of copper alloy grades
Limitations
- Low strength — 68 MPa (9.86 ksi), worse than 97% of copper alloy grades
- Difficult to machine — 25/100, worse than 86% of copper alloy grades
C81200-M05 properties
Typical room-temperature values for C81200-M05; 19 are specific to this condition. Other listed values are C81200 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C81200-M05 has a density of 8.91 g/cm³ (0.322 lb/in³), heavier than 80% of copper alloy grades. It melts at 1,065°C (1,949 °F).
Mechanical13
C81200-M05 has a yield strength of 68 MPa (9.86 ksi) and a tensile strength of 185 MPa (26.8 ksi) — weaker than 97% of copper alloy grades. Elongation at break is 38% and the elastic modulus is 112 GPa (16.2 Msi).
Thermal6
C81200-M05 is rated for continuous service to 200°C (392 °F). It conducts heat at 320 W/m·K (184.9 BTU/hr·ft·°F), better than 84% of copper alloy grades. Thermal expansion is 17.6 µm/m·K (9.78 µin/in·°F).
Electrical3
C81200-M05 conducts electricity at 80 % IACS, better than 84% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 58% of copper alloy grades.
Sustainability4
Producing a kilogram of C81200-M05 takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 50%.
Manufacturability8
C81200-M05's machinability is poor (25/100, worse than 86% of copper alloy grades); weldability good (65/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C81200-M05
Is C81200 easy to machine?
Gummy and stringy like pure copper (~20 % of AISI 1212): use sharp positive-rake tools, high speed, light-to-moderate feed, generous coolant; avoid dwelling to prevent smearing.
Can C81200 be welded?
Excellent for a copper — the P residual prevents steam/hydrogen embrittlement, so GTAW/GMAW with ERCu filler, high preheat (300–500 °C) and helium-rich shielding gives sound repair welds.
Can C81200 be formed, bent or molded?
Foundry alloy: needs large risers, chills and clean charge because of copper's high shrinkage and gas pickup; not intended for cold forming beyond light coining/straightening.
What surface finishes work on C81200?
Not anodizable; specify electroplating (Ni, Sn, Ag) for contacts, mechanical polishing or a chemical patina, and clear lacquer to stop atmospheric tarnish.
C81200 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 |
|---|---|---|
| Pdeoxidant residual — controls gas soundness and weldability | 0.05 – 0.07 | 0.06 |
| CuCu + Ag, 99.9 % min; remainder is the phosphorus residual and trace impurities | ≥ 99.9 (balance) | — |
C81200-M05 — frequently asked
What is C81200-M05 used for?
C81200-M05 is typically used for resistance welding electrode holders, mold inserts and high-conductivity structural castings. In short: high-conductivity cast copper; weld-repairable copper casting; age-hardenable Cu-Cr grade.
What is the yield strength of C81200-M05?
C81200-M05 has a typical yield strength of 68 MPa (9.86 ksi) and a tensile strength of 185 MPa (26.8 ksi) — weaker than 97% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is C81200-M05 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 86% of copper alloy grades). Gummy and stringy like pure copper (~20 % of AISI 1212): use sharp positive-rake tools, high speed, light-to-moderate feed, generous coolant; avoid dwelling to prevent smearing.
Can C81200-M05 be welded?
Yes — weldability is rated good (65/100). Excellent for a copper — the P residual prevents steam/hydrogen embrittlement, so GTAW/GMAW with ERCu filler, high preheat (300–500 °C) and helium-rich shielding gives sound repair welds.
What surface finishes work on C81200-M05?
Not anodizable; specify electroplating (Ni, Sn, Ag) for contacts, mechanical polishing or a chemical patina, and clear lacquer to stop atmospheric tarnish.
Can C81200-M05 be formed, bent or molded?
Foundry alloy: needs large risers, chills and clean charge because of copper's high shrinkage and gas pickup; not intended for cold forming beyond light coining/straightening.
What is the maximum service temperature of C81200-M05?
C81200-M05 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 C81200-M01 and C81200-M07?
M01 is the default condition — standard stocked/produced condition for one-off and small-lot electrical castings. M07: best choice when buying bar/tube stock for machined electrical parts — densest, most uniform structure. Yield strength is 62 MPa in M01 versus 75 MPa in M07.
Sources
- ASTM B824 — Standard Specification for General Requirements for Copper Alloy Castings — ASTM International (2022)
- Cast Copper Alloy UNS C81200 alloy data (Standards Handbook — Cast Copper and Copper Alloy Products) — Copper Development Association (copper.org) (2022)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Specialty Handbook: Copper and Copper Alloys — ASM International (2001)
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.