Copper Alloy C73500-H10
Supply condition
UNS C73500
H10 = extra spring hard
Maximum-strength strip for thin high-deflection springs; essentially no cross-grain formability.
Values for the H10 condition
Other C73500 tempers and conditions
C73500 is listed in 8 conditions; see the grade overview at C73500.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for deep drawing, spinning and severe bending of decorative parts before final work-hardening. | 145 | 385 | 40 | 78 HB | 6.5 % IACS |
As hot rolled | Mill hot-rolled plate/bar condition for machined blanks and parts that will be finished after forming. | 160 | 380 | 35 | 85 HB | 6.5 % IACS |
Quarter hard | Pick when moderate stiffness is needed but the part still has to be formed or bent across the grain. | 310 | 430 | 20 | 108 HB | 6.3 % IACS |
H02Default Half hard | The general-purpose stocked temper: good balance of strength, formability and finish for hardware, flatware and instrument parts. | 415 | 480 | 10 | 130 HB | 6.2 % IACS |
Full hard | Pick for flat springs, contacts and stiff stamped parts needing only gentle forming with the grain. | 525 | 585 | 4 | 160 HB | 6 % IACS |
Extra hard | Pick for high-load springs, snap parts and flat stock where maximum strength matters more than bending. | 570 | 655 | 3 | 180 HB | 6 % IACS |
Spring hard | Spring strip for relay blades, contacts and clips formed only in simple bends along the rolling direction. | 620 | 690 | 2 | 195 HB | 6 % IACS |
H10This page Extra spring hard | Maximum-strength strip for thin high-deflection springs; essentially no cross-grain formability. | 660 | 725 | 1.5 | 12 HRC | 6 % IACS |
What is C73500-H10?
C73500-H10 is C73500 supplied in the H10 condition — maximum-strength strip for thin high-deflection springs; essentially no cross-grain formability. C73500-H10 has a yield strength of 660 MPa (95.7 ksi) and a tensile strength of 725 MPa (105 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 1.5% and the elastic modulus is 130 GPa (18.9 Msi). C73500-H10 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,080°C (1,976 °F). H02 is the default condition FabDigit quotes; H10 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 90/100, better than 99% of copper alloy grades
- High strength — 660 MPa (95.7 ksi), better than 96% of copper alloy grades
- Stiff — 130 GPa (18.9 Msi), better than 89% of copper alloy grades
Limitations
- Limited ductility — 1.5%, worse than 98% of copper alloy grades
- Limited service temperature — 150°C (302 °F), worse than 96% 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 — 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 90% of copper alloy grades
C73500-H10 properties
Typical room-temperature values for C73500-H10; 21 are specific to this condition. Other listed values are C73500 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C73500-H10 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,080°C (1,976 °F).
Mechanical12
C73500-H10 has a yield strength of 660 MPa (95.7 ksi) and a tensile strength of 725 MPa (105 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 1.5% and the elastic modulus is 130 GPa (18.9 Msi).
Thermal6
C73500-H10 is rated for continuous service to 150°C (302 °F). It conducts heat at 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 90% of copper alloy grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
C73500-H10 conducts electricity at 6 % IACS, worse than 93% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C73500-H10 takes about 78 MJ of energy and emits 5.6 kg of CO₂ — more than 90% of copper alloy grades. Typical recycled content is 35%.
Manufacturability8
C73500-H10's machinability is fair (35/100, better than 51% of copper alloy grades); weldability fair (45/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C73500-H10
Is C73500 easy to machine?
Rated only ~20 % of free-cutting brass — gummy, work-hardening chips; use sharp positive-rake carbide/HSS tools, moderate speed, heavy feed and soluble-oil coolant, and avoid dwelling.
Can C73500 be welded?
Solders and brazes very well and resistance/spot welds acceptably; gas welding is not recommended because of zinc loss, and TIG requires low heat input plus post-weld stress relief.
Can C73500 be formed, bent or molded?
Excellent cold formability in O61/H01 (deep drawing, spinning, stamping); interanneal at 600–750 °C and stress-relieve hard tempers at ~250–300 °C to avoid ammonia stress-corrosion cracking.
What surface finishes work on C73500?
Takes a bright silver-white polish and buffs easily; commonly lacquered, oxidised/antiqued, or nickel-, chrome- or silver-plated. Not anodizable.
C73500 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 |
|---|---|---|
| Cu | 70.5 – 73.5 | 72 |
| NiNi + Co | 16.5 – 19.5 | 18 |
| Mn | ≤ 0.5 | — |
| Fe | ≤ 0.25 | — |
| Pb | ≤ 0.1 | — |
| Znremainder, ~7–13 % | balance | — |
C73500-H10 — frequently asked
What is C73500-H10 used for?
C73500-H10 is typically used for flatware, hardware fittings, optical/instrument parts and zippers. In short: spring-temper nickel silver; bright silver-white finish; low machinability, good formability.
What is the yield strength of C73500-H10?
C73500-H10 has a typical yield strength of 660 MPa (95.7 ksi) and a tensile strength of 725 MPa (105 ksi) — stronger than 96% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C73500-H10 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of copper alloy grades). Rated only ~20 % of free-cutting brass — gummy, work-hardening chips; use sharp positive-rake carbide/HSS tools, moderate speed, heavy feed and soluble-oil coolant, and avoid dwelling.
Can C73500-H10 be welded?
With care — weldability is rated fair (45/100). Solders and brazes very well and resistance/spot welds acceptably; gas welding is not recommended because of zinc loss, and TIG requires low heat input plus post-weld stress relief.
What surface finishes work on C73500-H10?
Takes a bright silver-white polish and buffs easily; commonly lacquered, oxidised/antiqued, or nickel-, chrome- or silver-plated. Not anodizable.
Can C73500-H10 be formed, bent or molded?
Excellent cold formability in O61/H01 (deep drawing, spinning, stamping); interanneal at 600–750 °C and stress-relieve hard tempers at ~250–300 °C to avoid ammonia stress-corrosion cracking.
What is the maximum service temperature of C73500-H10?
C73500-H10 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C73500-H02 and C73500-O61?
H02 is the default condition — the general-purpose stocked temper: good balance of strength, formability and finish for hardware, flatware and instrument parts. O61: pick for deep drawing, spinning and severe bending of decorative parts before final work-hardening. Yield strength is 415 MPa in H02 versus 145 MPa in O61.
Sources
- ASTM B122/B122M — Copper-Nickel-Tin, Copper-Nickel-Zinc (Nickel Silver) Plate, Sheet, Strip and Rolled Bar — ASTM International (2021)
- ASTM B151/B151M — Copper-Nickel-Zinc and Copper-Nickel Rod and Bar — ASTM International (2021)
- CDA Alloy Database — C73500 Nickel Silver 72-18 — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- GB/T 2040 / GB/T 2059 (BZn18-10 ) — 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.