Copper Alloy C75200-O61
Heat-treated state
UNS C75200 · EN CW409J
O61 = annealed
Choose for deep drawing, spinning and severe forming of flatware and instrument parts before final work-hardening.
Values for the O61 condition
Other C75200 tempers and conditions
C75200 is listed in 9 conditions; see the grade overview at C75200.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
O61This page Annealed | Choose for deep drawing, spinning and severe forming of flatware and instrument parts before final work-hardening. | 172 | 400 | 40 | 100 HB | 6 % IACS |
As hot rolled | Pick for hot-rolled plate/bar stock that will be machined or subsequently cold-finished; softest commercial mill condition. | 180 | 407 | 37 | 102 HB | — |
Annealed to 0.035 mm grain size | Grain-size-controlled soft strip for consistent draw/stamp behaviour and a fine, streak-free polished surface. | 190 | 414 | 38 | 107 HB | 6 % IACS |
Quarter hard | Best compromise when parts still need moderate bending or drawing but require more stiffness than annealed strip. | 310 | 448 | 15 | 133 HB | — |
H02Default Half hard | The default stocked strip/sheet temper: enough strength for flatware, escutcheons and hardware while still allowing gentle forming. | 427 | 517 | 6 | 160 HB | — |
Full hard | Use where flatness, edge stiffness and wear resistance matter — knife handles, trim strips, blanked contacts with only gentle bends. | 517 | 586 | 3 | 177 HB | — |
Extra hard | For high-strength flat parts and light springs where only very small-radius bends parallel to rolling are needed. | 586 | 655 | 2 | 188 HB | — |
Spring hard | Select for flat springs, clips, reed/valve parts and connector contacts needing high elastic limit with non-magnetic behaviour. | 640 | 700 | 2 | 198 HB | — |
Extra spring hard | Maximum cold-worked strength for thin strip springs and shims; essentially no bending capability across the grain. | 690 | 758 | 1 | 18 HRC | 5.5 % IACS |
What is C75200-O61?
C75200-O61 is C75200 heat treated to O61 — choose for deep drawing, spinning and severe forming of flatware and instrument parts before final work-hardening. C75200-O61 has a yield strength of 172 MPa (24.9 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 60% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 125 GPa (18.1 Msi). C75200-O61 has a density of 8.73 g/cm³ (0.315 lb/in³), lighter than 53% of copper alloy grades. It melts at 1,021°C (1,870 °F). H02 is the default condition FabDigit quotes; O61 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 92/100, better than 100% of copper alloy grades
- Forms and bends easily — 88/100, better than 87% of copper alloy grades
- High service temperature — 300°C (572 °F), better than 85% of copper alloy grades
- Ductile — tolerates forming and impact — 40%, better than 84% of copper alloy grades
Limitations
- Difficult to machine — 22/100, worse than 94% of copper alloy grades
- Low electrical conductivity — 6 % IACS, worse than 93% of copper alloy grades
- High embodied carbon — 5.6 kg CO₂/kg, worse than 91% of copper alloy grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades
C75200-O61 properties
Typical room-temperature values for C75200-O61; 15 are specific to this condition. Other listed values are C75200 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C75200-O61 has a density of 8.73 g/cm³ (0.315 lb/in³), lighter than 53% of copper alloy grades. It melts at 1,021°C (1,870 °F).
Mechanical12
C75200-O61 has a yield strength of 172 MPa (24.9 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 60% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 125 GPa (18.1 Msi).
Thermal6
C75200-O61 is rated for continuous service to 300°C (572 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
C75200-O61 conducts electricity at 6 % IACS, worse than 93% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 69% of copper alloy grades.
Sustainability4
Producing a kilogram of C75200-O61 takes about 82 MJ of energy and emits 5.6 kg of CO₂ — more than 91% of copper alloy grades. Typical recycled content is 40%.
Manufacturability8
C75200-O61's machinability is poor (22/100, worse than 94% of copper alloy grades); weldability fair (50/100); formability excellent (88/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C75200-O61
Is C75200 easy to machine?
Gummy and abrasive on tooling — rating ~20 % of free-cutting brass; use sharp positive-rake carbide, high speed, low feed and generous coolant, or switch to leaded C79200 for screw-machine work.
Can C75200 be welded?
Solders and silver-brazes excellently; resistance and GTAW welding are workable with low heat input and matching Cu-Ni filler, but zinc fuming, hot-shortness and post-weld colour mismatch limit fusion welding.
Can C75200 be formed, bent or molded?
Anneal at 600–750 °C for deep drawing/spinning; work-hardens fast, so plan interstage anneals and stress-relieve cold-worked parts (~250 °C) to avoid ammonia-related stress-corrosion cracking.
What surface finishes work on C75200?
Polishes to a bright silver-white lustre and takes silver, nickel or chrome plating readily; lacquer or plate for tarnish protection — it cannot be anodized.
C75200 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 |
|---|---|---|
| CuCu + named elements ≥ 99.5 % | 63.5 – 66.5 | 65 |
| NiNi + Co | 16.5 – 19.5 | 18 |
| Pb | ≤ 0.05 | — |
| Fe | ≤ 0.25 | — |
| Mn | ≤ 0.5 | — |
| Zn | balance | — |
C75200-O61 — frequently asked
What is C75200-O61 used for?
C75200-O61 is typically used for flatware and cutlery, musical instrument fittings, zippers, coinage blanks and optical frames. In short: whitest nickel silver; highest-nickel 65-18 grade; flatware-grade appearance.
What is the yield strength of C75200-O61?
C75200-O61 has a typical yield strength of 172 MPa (24.9 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 60% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C75200-O61 easy to machine?
Not especially — machinability is rated poor (22/100, worse than 94% of copper alloy grades). Gummy and abrasive on tooling — rating ~20 % of free-cutting brass; use sharp positive-rake carbide, high speed, low feed and generous coolant, or switch to leaded C79200 for screw-machine work.
Can C75200-O61 be welded?
With care — weldability is rated fair (50/100). Solders and silver-brazes excellently; resistance and GTAW welding are workable with low heat input and matching Cu-Ni filler, but zinc fuming, hot-shortness and post-weld colour mismatch limit fusion welding.
What surface finishes work on C75200-O61?
Polishes to a bright silver-white lustre and takes silver, nickel or chrome plating readily; lacquer or plate for tarnish protection — it cannot be anodized.
Can C75200-O61 be formed, bent or molded?
Anneal at 600–750 °C for deep drawing/spinning; work-hardens fast, so plan interstage anneals and stress-relieve cold-worked parts (~250 °C) to avoid ammonia-related stress-corrosion cracking.
What is the maximum service temperature of C75200-O61?
C75200-O61 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C75200-H02 and C75200-H10?
H02 is the default condition — the default stocked strip/sheet temper: enough strength for flatware, escutcheons and hardware while still allowing gentle forming. H10: maximum cold-worked strength for thin strip springs and shims; essentially no bending capability across the grain. Yield strength is 427 MPa in H02 versus 690 MPa in H10.
Sources
- ASTM B122/B122M — Copper-Nickel-Zinc (Nickel Silver) Plate, Sheet, Strip and Rolled Bar — ASTM International (2022)
- ASTM B151/B151M — Copper-Nickel-Zinc and Copper-Nickel Rod and Bar — ASTM International (2021)
- CDA Alloy C75200 property datasheet — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- EN 12163 / CW409J (CuNi18Zn20) wrought nickel silver — CEN (2016)
- GB/T 2059 / GB/T 2040 (BZn18-17) — SAC (2017)
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.