Copper Alloy C81100
UNS C81100 · ASTM B824, B369
C81100 (ASTM B824/B369) is a near-pure copper casting alloy that delivers 92 % IACS and 346 W/m·K in castable form, for conductor and connector bodies that cannot be machined from wrought stock.
Reference datasheet — C81100 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 M01 condition
C81100 tempers and conditions
C81100 is supplied in 6 conditions, soft to hard. M01 is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Cast and annealed | Anneal/homogenize when maximum electrical conductivity, dimensional stability and stress relief matter more than strength. | 55 | 165 | 45 | 40 HB | 95 % IACS |
M01Default As sand cast | Default supply condition for one-off and low-volume electrical castings; lowest tooling cost, coarsest grain. | 62 | 172 | 40 | 44 HB | 92 % IACS |
As plaster cast | Higher-volume parts with finer grain, better surface and slightly higher strength than sand cast. | 62 | 179 | 42 | 45 HB | 92 % IACS |
As investment cast | Choose for small, thin-walled contact and terminal bodies where near-net shape saves difficult copper machining. | 62 | 172 | 38 | 44 HB | 91 % IACS |
As centrifugally cast | For rings, sleeves and bushings needing dense, porosity-free conductive sections. | 65 | 180 | 42 | 46 HB | 92 % IACS |
As continuous cast | Continuous-cast bar and tube stock: densest, most uniform, highest as-cast strength; best when machining a solid conductive blank. | 76 | 195 | 35 | 50 HB | 93 % IACS |
What is C81100?
C81100 (ASTM B824/B369) is a near-pure copper casting alloy that delivers 92 % IACS and 346 W/m·K in castable form, for conductor and connector bodies that cannot be machined from wrought stock. Typical as-cast properties are 172 MPa tensile strength, 62 MPa yield, 40 % elongation and 44 HB, with service to 250 °C. It is difficult to cast because pure copper absorbs gas, has poor fluidity and 4–5 % shrinkage, and machinability is only about 20 % of free-cutting brass; use C80100 where the highest conductivity and vacuum-grade purity are needed. C81100 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,065°C (1,949 °F). C81100 has a yield strength of 62 MPa (8.99 ksi) and a tensile strength of 172 MPa (24.9 ksi) — weaker than 99% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 115 GPa (16.7 Msi).
What is C81100 used for?
- electrical connector castings
- grounding hardware
- conductor fittings
Advantages
- High electrical conductivity — 92 % IACS, better than 89% of copper alloy grades
- Conducts heat well — 346 W/m·K (199.9 BTU/hr·ft·°F), better than 87% of copper alloy grades
- Ductile — tolerates forming and impact — 40%, better than 84% of copper alloy grades
Limitations
- Low strength — 62 MPa (8.99 ksi), worse than 99% of copper alloy grades
- Difficult to machine — 22/100, worse than 94% of copper alloy grades
C81100 properties
Typical room-temperature values for C81100-M01; bars are the position among copper alloy grades.
Physical3
C81100 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,065°C (1,949 °F).
Mechanical14
C81100 has a yield strength of 62 MPa (8.99 ksi) and a tensile strength of 172 MPa (24.9 ksi) — weaker than 99% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
C81100 is rated for continuous service to 250°C (482 °F). It conducts heat at 346 W/m·K (199.9 BTU/hr·ft·°F), better than 87% of copper alloy grades. Thermal expansion is 17.7 µm/m·K (9.83 µin/in·°F).
Electrical3
C81100 conducts electricity at 92 % IACS, better than 89% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 69% of copper alloy grades.
Sustainability4
Producing a kilogram of C81100 takes about 57 MJ of energy and emits 3.8 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 45%.
Manufacturability8
C81100's machinability is poor (22/100, worse than 94% of copper alloy grades); weldability fair (45/100); formability good (55/100).
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. C81100 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C81100
Is C81100 easy to machine?
Gummy and stringy (rating ~20 % of free-cutting brass) — use sharp positive-rake tools, high speed, light feed, generous flood coolant; avoid built-up edge with polished flutes.
Can C81100 be welded?
GTAW/GMAW possible but the huge thermal conductivity demands 400–600 °C preheat and high heat input; brazing or silver soldering is usually preferred for joining conductor castings.
Can C81100 be formed, bent or molded?
Difficult to cast: pure copper is gas-absorbing with poor fluidity and ~4–5 % shrinkage, so use deoxidized melt practice, heavy risering, chills and thick sections; light cold coining/staking is possible after casting.
C81100 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 |
|---|---|---|
| Other (total)residual impurities; O, P and S kept low to protect conductivity | ≤ 0.3 | 0.1 |
| CuCu (incl. Ag) 99.70 % min per ASTM B824 / CDA C81100; no other elements individually specified | ≥ 99.7 (balance) |
What surface finishes work on C81100?
Not anodizable — electroplate Ni, Ag or Sn for contact surfaces and tarnish control, or apply clear lacquer/benzotriazole passivation; polishes to a bright finish easily.
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 C81100 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B824B369
- Other
- BCu-2
How much does C81100 cost?
C81100 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.
C81100 — frequently asked
What is C81100 used for?
C81100 is typically used for electrical connector castings, grounding hardware and conductor fittings. In short: castable 92 % IACS copper; 250 °C service ceiling; demanding foundry practice.
What is the yield strength of C81100?
C81100 has a typical yield strength of 62 MPa (8.99 ksi) and a tensile strength of 172 MPa (24.9 ksi) — weaker than 99% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is C81100 easy to machine?
Not especially — machinability is rated poor (22/100, worse than 94% of copper alloy grades). Gummy and stringy (rating ~20 % of free-cutting brass) — use sharp positive-rake tools, high speed, light feed, generous flood coolant; avoid built-up edge with polished flutes.
Can C81100 be welded?
With care — weldability is rated fair (45/100). GTAW/GMAW possible but the huge thermal conductivity demands 400–600 °C preheat and high heat input; brazing or silver soldering is usually preferred for joining conductor castings.
What surface finishes work on C81100?
Not anodizable — electroplate Ni, Ag or Sn for contact surfaces and tarnish control, or apply clear lacquer/benzotriazole passivation; polishes to a bright finish easily.
Can C81100 be formed, bent or molded?
Difficult to cast: pure copper is gas-absorbing with poor fluidity and ~4–5 % shrinkage, so use deoxidized melt practice, heavy risering, chills and thick sections; light cold coining/staking is possible after casting.
What is the maximum service temperature of C81100?
C81100 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 C81100-M01 and C81100-M07?
M01 is the default condition — default supply condition for one-off and low-volume electrical castings; lowest tooling cost, coarsest grain. M07: continuous-cast bar and tube stock: densest, most uniform, highest as-cast strength; best when machining a solid conductive blank. Yield strength is 62 MPa in M01 versus 76 MPa in M07.
How much does C81100 cost?
C81100 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 B824 — Standard Specification for General Requirements for Copper Alloy Castings — ASTM International (2022)
- ASTM B369 — Copper-Nickel Alloy Castings (referenced designation family) — ASTM International (2021)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM International (2019)
- CDA Alloy Datasheet C81100 — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 15 — Casting (copper alloy foundry practice) — ASM International (2008)
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.