Copper Alloy C10500-H04
Supply condition · default condition
UNS C10500
H04 = full hard
Default stocked temper for bar, plate and commutator/busbar profiles — highest strength that still machines and solders easily.
Values for the H04 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 |
H04DefaultThis page 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 |
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-H04?
C10500-H04 is C10500 supplied in the H04 condition — default stocked temper for bar, plate and commutator/busbar profiles — highest strength that still machines and solders easily. C10500-H04 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 64% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 117 GPa (17 Msi). C10500-H04 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).
Advantages
- Conducts heat well — 388 W/m·K (224.2 BTU/hr·ft·°F), better than 95% of copper alloy grades
- High electrical conductivity — 99 % IACS, better than 95% of copper alloy grades
- Readily welded — 60/100, better than 76% of copper alloy grades
Limitations
- Limited ductility — 8%, worse than 83% of copper alloy grades
C10500-H04 properties
Typical room-temperature values for C10500-H04; 16 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-H04 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-H04 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 64% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C10500-H04 is rated for continuous service to 220°C (428 °F). It conducts heat at 388 W/m·K (224.2 BTU/hr·ft·°F), better than 95% of copper alloy grades. Thermal expansion is 17 µm/m·K (9.44 µin/in·°F).
Electrical3
C10500-H04 conducts electricity at 99 % IACS, better than 95% 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-H04 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-H04's machinability is poor (28/100, worse than 78% of copper alloy grades); weldability good (60/100); formability fair (50/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C10500-H04
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-H04 — frequently asked
What is C10500-H04 used for?
C10500-H04 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-H04?
C10500-H04 has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 64% of copper alloy grades. Strength varies by condition: see the 12 listed tempers.
Is C10500-H04 easy to machine?
Not especially — machinability is rated poor (28/100, worse than 78% 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-H04 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-H04?
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-H04 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-H04?
C10500-H04 is rated for continuous use to about 220°C (428 °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.