Copper Alloy C10400-H03
Supply condition
UNS C10400 · EN CW017A
H03 = three-quarter hard
Intermediate step to full hard for flat parts needing higher yield but some residual bend ductility.
Values for the H03 condition
Other C10400 tempers and conditions
C10400 is listed in 10 conditions; see the grade overview at C10400.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled and annealed | Fully soft condition for deep drawing, spinning, heavy bending and maximum conductivity. | 76 | 225 | 45 | 45 HB | 101 % IACS |
As hot rolled | Hot-rolled plate/bar for bus bar and heavy conductor where soft, workable copper in thick section is needed. | 90 | 235 | 45 | 45 HB | 101 % IACS |
1/8 hard | Slight temper for flatness and handling stiffness while keeping near-full formability. | 195 | 250 | 30 | 60 HB | 101 % IACS |
Quarter hard | Compromise temper for parts that are formed after cutting but need more stiffness than soft copper. | 205 | 262 | 25 | 70 HB | 100 % IACS |
Half hard | Most common general-purpose strip/bar temper: good strength with usable bending across the grain. | 250 | 290 | 14 | 82 HB | 100 % IACS |
H03This page Three-quarter hard | Intermediate step to full hard for flat parts needing higher yield but some residual bend ductility. | 280 | 315 | 10 | 88 HB | 100 % IACS |
H04Default Full hard | Default stocked condition for bus bar, commutator segments and hard-drawn conductors that must resist softening during soldering/brazing and service heating. | 310 | 345 | 6 | 95 HB | 100 % IACS |
Extra hard | Higher-strength strip/wire for contacts and clips where only gentle forming is required. | 330 | 365 | 5 | 100 HB | 99 % IACS |
Spring hard | Spring-temper strip/wire for current-carrying springs, brush shunts and contact fingers. | 345 | 380 | 4 | 105 HB | 99 % IACS |
Extra spring hard | Maximum cold-worked strength for thin springs and shunt strip; essentially no bend ductility across grain. | 365 | 395 | 4 | 108 HB | 98 % IACS |
What is C10400-H03?
C10400-H03 is C10400 supplied in the H03 condition — intermediate step to full hard for flat parts needing higher yield but some residual bend ductility. C10400-H03 has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 315 MPa (45.7 ksi) — stronger than 59% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 117 GPa (17 Msi). C10400-H03 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; H03 is available on request or by drawing note.
Advantages
- High electrical conductivity — 100 % IACS, better than 96% of copper alloy grades
- Conducts heat well — 388 W/m·K (224.2 BTU/hr·ft·°F), better than 95% of copper alloy grades
- Readily welded — 65/100, better than 80% of copper alloy grades
Limitations
- Limited ductility — 10%, worse than 76% of copper alloy grades
C10400-H03 properties
Typical room-temperature values for C10400-H03; 13 are specific to this condition. Other listed values are C10400 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C10400-H03 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
C10400-H03 has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 315 MPa (45.7 ksi) — stronger than 59% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C10400-H03 is rated for continuous service to 235°C (455 °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
C10400-H03 conducts electricity at 100 % IACS, better than 96% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 58% of copper alloy grades.
Sustainability4
Producing a kilogram of C10400-H03 takes about 57 MJ of energy and emits 3.8 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 10%.
Manufacturability8
C10400-H03's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability good (65/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C10400-H03
Is C10400 easy to machine?
Gummy and stringy — use sharp positive-rake tools, high speed, generous coolant; expect ~20% of free-cutting brass, choose H04 or harder for better chip breaking.
Can C10400 be welded?
GTAW/GMAW/EBW and resistance welding are all workable with preheat (high thermal conductivity); no oxygen means no hydrogen embrittlement, but the weld HAZ anneals back to soft even in the Ag-bearing grade.
Can C10400 be formed, bent or molded?
Excellent in O25/M20 for deep drawing, spinning and heavy bending; interanneal at 350–600 °C between severe steps, and limit H06–H10 to simple gentle bends.
What surface finishes work on C10400?
Not anodizable; solders/brazes readily, takes bright polish, and is commonly Ni, Sn or Ag electroplated or chemically blackened/lacquered to control tarnish.
C10400 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 |
|---|---|---|
| Ag8 troy oz/ton min; counted in the Cu+Ag total | ≥ 0.03 | 0.03 |
| O10 ppm max | ≤ 0 | 5×10⁻⁴ |
| Ptypical impurity limit per ASTM B170 OF practice | ≤ 3×10⁻⁴ | — |
| S | ≤ 0 | — |
| Bi | ≤ 0 | — |
| Pb | ≤ 0 | — |
| Se | ≤ 0 | — |
| Te | ≤ 0 | — |
| CuCu + Ag, min 99.95% (oxygen-free, no deoxidizer residues) | ≥ 99.95 (balance) | — |
C10400-H03 — frequently asked
What is C10400-H03 used for?
C10400-H03 is typically used for commutator bars, motor windings requiring softening resistance and welding electrodes. In short: silver-bearing oxygen-free copper; softening-resistant conductor; 100 % IACS at 345 MPa.
What is the yield strength of C10400-H03?
C10400-H03 has a typical yield strength of 280 MPa (40.6 ksi) and a tensile strength of 315 MPa (45.7 ksi) — stronger than 59% of copper alloy grades. Strength varies by condition: see the 10 listed tempers.
Is C10400-H03 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Gummy and stringy — use sharp positive-rake tools, high speed, generous coolant; expect ~20% of free-cutting brass, choose H04 or harder for better chip breaking.
Can C10400-H03 be welded?
Yes — weldability is rated good (65/100). GTAW/GMAW/EBW and resistance welding are all workable with preheat (high thermal conductivity); no oxygen means no hydrogen embrittlement, but the weld HAZ anneals back to soft even in the Ag-bearing grade.
What surface finishes work on C10400-H03?
Not anodizable; solders/brazes readily, takes bright polish, and is commonly Ni, Sn or Ag electroplated or chemically blackened/lacquered to control tarnish.
Can C10400-H03 be formed, bent or molded?
Excellent in O25/M20 for deep drawing, spinning and heavy bending; interanneal at 350–600 °C between severe steps, and limit H06–H10 to simple gentle bends.
What is the maximum service temperature of C10400-H03?
C10400-H03 is rated for continuous use to about 235°C (455 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C10400-H04 and C10400-O25?
H04 is the default condition — default stocked condition for bus bar, commutator segments and hard-drawn conductors that must resist softening during soldering/brazing and service heating. O25: fully soft condition for deep drawing, spinning, heavy bending and maximum conductivity. Yield strength is 310 MPa in H04 versus 76 MPa in O25.
Sources
- ASTM B224 — Standard Classification of Coppers — ASTM International (2021)
- 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)
- EN 13601 / EN 13604 — Copper for electrical purposes (CW017A) — CEN (2021)
- CDA Alloy C10400 property datasheet — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
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.