Copper Alloy C10500-H08
Supply condition
UNS C10500
H08 = spring hard
Heavily cold rolled strip for flat springs, contact fingers and EMI gaskets needing resilience.
Values for the H08 condition
Other C10500 tempers and conditions
C10500 is listed in 12 conditions; see the grade overview at C10500.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As hot extruded | Extruded rod, tube and profile in the as-pressed state, typically drawn or annealed afterwards. | 62 | 221 | 50 | 42 HB | 100 % IACS |
Annealed to 0.050 mm grain size | Softest stock condition — pick for deep drawing, spinning, tight bends and maximum conductivity. | 69 | 221 | 45 | 45 HB | 101 % IACS |
As hot rolled | Mill condition for hot-rolled plate and busbar where forming and conductivity matter more than strength. | 69 | 228 | 45 | 45 HB | 100 % IACS |
Hot rolled and annealed | Fine-grain annealed plate/bar for a smoother formed surface than coarse-grain OS050. | 76 | 234 | 45 | 48 HB | 101 % IACS |
1/8 hard | Minimal cold work for flatness and handling stiffness while keeping most of the annealed ductility. | 170 | 250 | 30 | 52 HB | 100 % IACS |
Light drawn | Lightly drawn tube/rod: straight and dimensionally accurate but still bendable for coils and fittings. | 195 | 255 | 25 | 60 HB | 100 % IACS |
Quarter hard | Best compromise when a part must be moderately bent yet hold shape — gaskets, shields, formed terminals. | 220 | 262 | 25 | 58 HB | 100 % IACS |
Half hard | General-purpose strip/bar temper for stamped contacts and busbar that still needs 90° bends. | 250 | 290 | 14 | 70 HB | 99 % IACS |
H04Default Full hard | Default stocked temper for bar, plate and commutator/busbar profiles — highest strength that still machines and solders easily. | 310 | 345 | 8 | 90 HB | 99 % IACS |
H08This page Spring hard | Heavily cold rolled strip for flat springs, contact fingers and EMI gaskets needing resilience. | 345 | 379 | 4 | 95 HB | 98 % IACS |
Hard drawn | Hard-drawn wire/rod for magnet wire, commutator risers and overhead conductors that must resist softening after soldering. | 350 | 400 | 2.5 | 95 HB | 98 % IACS |
Extra spring hard | Maximum cold-rolled strength available in strip; use only for flat parts with very generous bend radii. | 365 | 393 | 3 | 100 HB | 98 % IACS |
What is C10500-H08?
C10500-H08 is C10500 supplied in the H08 condition — heavily cold rolled strip for flat springs, contact fingers and EMI gaskets needing resilience. C10500-H08 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 379 MPa (55 ksi) — stronger than 73% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi). C10500-H08 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,065°C (1,949 °F). H04 is the default condition FabDigit quotes; H08 is available on request or by drawing note.
Advantages
- High electrical conductivity — 98 % IACS, better than 94% of copper alloy grades
- Conducts heat well — 386 W/m·K (223 BTU/hr·ft·°F), better than 93% of copper alloy grades
- Readily welded — 60/100, better than 76% of copper alloy grades
Limitations
- Limited ductility — 4%, worse than 96% of copper alloy grades
C10500-H08 properties
Typical room-temperature values for C10500-H08; 13 are specific to this condition. Other listed values are C10500 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C10500-H08 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,065°C (1,949 °F).
Mechanical13
C10500-H08 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 379 MPa (55 ksi) — stronger than 73% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C10500-H08 is rated for continuous service to 200°C (392 °F). It conducts heat at 386 W/m·K (223 BTU/hr·ft·°F), better than 93% of copper alloy grades. Thermal expansion is 17 µm/m·K (9.44 µin/in·°F).
Electrical3
C10500-H08 conducts electricity at 98 % IACS, better than 94% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C10500-H08 takes about 57 MJ of energy and emits 4 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 10%.
Manufacturability8
C10500-H08's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability good (60/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C10500-H08
Is C10500 easy to machine?
Gummy and stringy at ~20 % of AISI 1212 — use sharp positive-rake tools, high speed, low feed and generous flood coolant; harder tempers (H04/H08) chip better than annealed.
Can C10500 be welded?
Oxygen-free so no hydrogen embrittlement; GTAW/GMAW with ERCu filler, high preheat (200–500 °C) on thick sections due to the 390 W/m·K conductivity; resistance welding is poor.
Can C10500 be formed, bent or molded?
Excellent cold formability in OS050/O25 (deep draw, spin, coin); interanneal at 400–600 °C — note the Ag raises the recrystallization temperature ~100 °C over pure OF copper.
What surface finishes work on C10500?
Not anodizable; electroplate Ni/Ag/Sn for contacts, or use bright dip / chemical blackening; polishes to a high luster but tarnishes without lacquer or Sn plating.
C10500 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 |
|---|---|---|
| Ag≈10 troy oz/ton minimum silver — raises softening temperature | ≥ 0.03 | 0.04 |
| O≤10 ppm oxygen | ≤ 0 | 5×10⁻⁴ |
| P | ≤ 3×10⁻⁴ | — |
| Bi | ≤ 0 | — |
| Se | ≤ 0 | — |
| Te | ≤ 0 | — |
| S | ≤ 0 | — |
| Pb | ≤ 5×10⁻⁴ | — |
| Fe | ≤ 0 | — |
| Ni | ≤ 0 | — |
| Zn | ≤ 1×10⁻⁴ | — |
| CuCu + Ag ≥ 99.95 % (oxygen-free, no deoxidizers) | ≥ 99.95 (balance) | — |
C10500-H08 — frequently asked
What is C10500-H08 used for?
C10500-H08 is typically used for locomotive/traction motor conductors, high-temperature electrical windings and welding cable. In short: highest-silver oxygen-free copper; best softening resistance; 99 % IACS conductivity.
What is the yield strength of C10500-H08?
C10500-H08 has a typical yield strength of 345 MPa (50 ksi) and a tensile strength of 379 MPa (55 ksi) — stronger than 73% of copper alloy grades. Strength varies by condition: see the 12 listed tempers.
Is C10500-H08 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Gummy and stringy at ~20 % of AISI 1212 — use sharp positive-rake tools, high speed, low feed and generous flood coolant; harder tempers (H04/H08) chip better than annealed.
Can C10500-H08 be welded?
Yes — weldability is rated good (60/100). Oxygen-free so no hydrogen embrittlement; GTAW/GMAW with ERCu filler, high preheat (200–500 °C) on thick sections due to the 390 W/m·K conductivity; resistance welding is poor.
What surface finishes work on C10500-H08?
Not anodizable; electroplate Ni/Ag/Sn for contacts, or use bright dip / chemical blackening; polishes to a high luster but tarnishes without lacquer or Sn plating.
Can C10500-H08 be formed, bent or molded?
Excellent cold formability in OS050/O25 (deep draw, spin, coin); interanneal at 400–600 °C — note the Ag raises the recrystallization temperature ~100 °C over pure OF copper.
What is the maximum service temperature of C10500-H08?
C10500-H08 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 C10500-H04 and C10500-M30?
H04 is the default condition — default stocked temper for bar, plate and commutator/busbar profiles — highest strength that still machines and solders easily. M30: extruded rod, tube and profile in the as-pressed state, typically drawn or annealed afterwards. Yield strength is 310 MPa in H04 versus 62 MPa in M30.
Sources
- ASTM B170 — Oxygen-Free Electrolytic Copper Refinery Shapes — ASTM International (2019)
- ASTM B152/B152M — Copper Sheet, Strip, Plate and Rolled Bar — ASTM International (2019)
- ASTM B187/B187M — Copper Bus Bar, Rod and Shapes — ASTM International (2020)
- CDA UNS C10500 alloy datasheet (copper.org) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
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.