Copper Alloy C71000
UNS C71000 · GB B19
C71000 is an 80Cu-20Ni wrought copper-nickel (CuNi20Fe, alloy B19) supplied in O61, M20 and H01–H08 tempers under the C70000-series specifications.
Reference datasheet — C71000 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 O61 condition
C71000 tempers and conditions
C71000 is supplied in 7 conditions, soft to hard. O61 is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
O61Default Annealed | Standard stocked condition for condenser/heat-exchanger tube and deep-drawn parts; maximum ductility and formability. | 110 | 340 | 40 | 75 HB | 6.5 % IACS |
As hot rolled | Hot-rolled plate/bar taken as-produced; used where plate is later formed, welded or machined and temper is not critical. | 140 | 365 | 35 | 82 HB | 6.5 % IACS |
Quarter hard | Light cold work for parts needing more stiffness/strength than annealed while retaining good bending ability. | 275 | 415 | 20 | 105 HB | 6.5 % IACS |
Half hard | General-purpose strengthened strip/bar; good balance of strength and moderate forming for brackets and fittings. | 415 | 480 | 12 | 135 HB | 6.5 % IACS |
Full hard | High-strength strip/wire for flat springs, contacts and wear parts where only gentle bending is required. | 515 | 550 | 5 | 160 HB | 6.5 % IACS |
Extra hard | For flat springs and stamped parts needing near-maximum strength with minimal forming after rolling. | 550 | 585 | 4 | 175 HB | 6.5 % IACS |
Spring hard | Maximum cold-worked strength for spring strip and wire; very limited ductility, bends only along favourable grain direction. | 570 | 620 | 3 | 185 HB | 6.5 % IACS |
What is C71000?
C71000 is an 80Cu-20Ni wrought copper-nickel (CuNi20Fe, alloy B19) supplied in O61, M20 and H01–H08 tempers under the C70000-series specifications. It sits between the 90/10 and 70/30 grades, giving 340 MPa tensile, 110 MPa yield, 40 % elongation, 138 GPa modulus and a corrosion resistance score of 75, and is used as condenser and marine tube, ferrule stock and strip. Conductivity is 37 W/m·K and 6.5 % IACS with a 320 °C maximum service temperature; machinability is low at 20, and C71500-type 70/30 alloys remain the default for high-velocity seawater. C71000 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,099°C (2,010 °F). C71000 has a yield strength of 110 MPa (16 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 82% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 138 GPa (20 Msi).
What is C71000 used for?
- condenser tubes
- ferrule stock
- marine tubing
- coinage stock
Advantages
- Stiff — 138 GPa (20 Msi), better than 95% of copper alloy grades
- Readily welded — 85/100, better than 95% of copper alloy grades
- High service temperature — 320°C (608 °F), better than 93% of copper alloy grades
- Polishes to a fine finish — 85/100, better than 92% of copper alloy grades
- Good corrosion resistance — 75/100, better than 90% of copper alloy grades
Limitations
- Difficult to machine — 20/100, worse than 98% of copper alloy grades
- Low electrical conductivity — 6.5 % IACS, worse than 91% of copper alloy grades
- High embodied carbon — 5.2 kg CO₂/kg, worse than 88% of copper alloy grades
- Poor heat conductor — 37 W/m·K (21.4 BTU/hr·ft·°F), worse than 85% of copper alloy grades
- Low strength — 110 MPa (16 ksi), worse than 82% of copper alloy grades
C71000 properties
Typical room-temperature values for C71000-O61; bars are the position among copper alloy grades.
Physical3
C71000 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,099°C (2,010 °F).
Mechanical13
C71000 has a yield strength of 110 MPa (16 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 82% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 138 GPa (20 Msi).
Thermal6
C71000 is rated for continuous service to 320°C (608 °F). It conducts heat at 37 W/m·K (21.4 BTU/hr·ft·°F), worse than 85% of copper alloy grades. Thermal expansion is 15.6 µm/m·K (8.67 µin/in·°F).
Electrical3
C71000 conducts electricity at 6.5 % IACS, worse than 91% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (75/100), better than 90% of copper alloy grades.
Sustainability4
Producing a kilogram of C71000 takes about 72 MJ of energy and emits 5.2 kg of CO₂ — more than 86% of copper alloy grades. Typical recycled content is 30%.
Manufacturability8
C71000's machinability is poor (20/100, worse than 98% of copper alloy grades); weldability excellent (85/100); formability excellent (90/100).
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. C71000 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C71000
Is C71000 easy to machine?
Gummy and work-hardening — use sharp, positive-rake carbide, rigid setups, heavy feeds at 25–60 m/min with flood coolant; rating ≈20 % of free-cutting brass.
Can C71000 be welded?
Excellent with GTAW/GMAW using ERCuNi (70/30) filler; keep interpass clean and sulfur/lead free, no preheat, low heat input to avoid hot cracking.
Can C71000 be formed, bent or molded?
Anneal at 700–800 °C for deep drawing and tube bending; cold-work rates are high so interstage annealing is needed above ~40 % reduction.
C71000 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 |
|---|---|---|
| NiNi + Co | 19 – 23 | 20 |
| Fe | ≤ 1 | 0.5 |
| Mn | ≤ 1 | 0.5 |
| Zn | ≤ 1 | |
| Pb | ≤ 0.05 | |
| CuCu + Ag = remainder, ≈78 % | balance |
What surface finishes work on C71000?
Not anodizable — polishes to a bright silvery finish, accepts tin, nickel or chrome plating; natural protective oxide should be allowed to form for seawater service.
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 C71000 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- GB (China)
- B19
- Similar grades
- CuNi20Fe
How much does C71000 cost?
C71000 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.
C71000 — frequently asked
What is C71000 used for?
C71000 is typically used for condenser tubes, ferrule stock, marine tubing and coinage stock. In short: mid-nickel 80/20 Cu-Ni; between 90/10 and 70/30; coinage and condenser strip.
What is the yield strength of C71000?
C71000 has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 82% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C71000 easy to machine?
Not especially — machinability is rated poor (20/100, worse than 98% of copper alloy grades). Gummy and work-hardening — use sharp, positive-rake carbide, rigid setups, heavy feeds at 25–60 m/min with flood coolant; rating ≈20 % of free-cutting brass.
Can C71000 be welded?
Yes — weldability is rated excellent (85/100). Excellent with GTAW/GMAW using ERCuNi (70/30) filler; keep interpass clean and sulfur/lead free, no preheat, low heat input to avoid hot cracking.
What surface finishes work on C71000?
Not anodizable — polishes to a bright silvery finish, accepts tin, nickel or chrome plating; natural protective oxide should be allowed to form for seawater service.
Can C71000 be formed, bent or molded?
Anneal at 700–800 °C for deep drawing and tube bending; cold-work rates are high so interstage annealing is needed above ~40 % reduction.
What is the maximum service temperature of C71000?
C71000 is rated for continuous use to about 320°C (608 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C71000-O61 and C71000-H08?
O61 is the default condition — standard stocked condition for condenser/heat-exchanger tube and deep-drawn parts; maximum ductility and formability. H08: maximum cold-worked strength for spring strip and wire; very limited ductility, bends only along favourable grain direction. Yield strength is 110 MPa in O61 versus 570 MPa in H08.
How much does C71000 cost?
C71000 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 B111/B111M — Copper and Copper-Alloy Seamless Condenser Tubes — ASTM International (2021)
- ASTM B122/B122M — Copper-Nickel Plate, Sheet, Strip and Rolled Bar — ASTM International (2022)
- CDA Alloy Datasheet C71000 (UNS C71000) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (copper-nickel in seawater) — ASM International (2005)
- GB/T 2059 / GB/T 8890 (B19) (2017)
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.