Copper Alloy C10400-H04
Supply condition · default condition
UNS C10400 · EN CW017A
H04 = full hard
Default stocked condition for bus bar, commutator segments and hard-drawn conductors that must resist softening during soldering/brazing and service heating.
Values for the H04 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 |
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 |
H04DefaultThis page 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-H04?
C10400-H04 is C10400 supplied in the H04 condition — default stocked condition for bus bar, commutator segments and hard-drawn conductors that must resist softening during soldering/brazing and service heating. C10400-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 6% and the elastic modulus is 117 GPa (17 Msi). C10400-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
- 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 — 6%, worse than 89% of copper alloy grades
C10400-H04 properties
Typical room-temperature values for C10400-H04; 17 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-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
C10400-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 6% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C10400-H04 is rated for continuous service to 230°C (446 °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-H04 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-H04 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-H04's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability good (65/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C10400-H04
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-H04 — frequently asked
What is C10400-H04 used for?
C10400-H04 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-H04?
C10400-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 10 listed tempers.
Is C10400-H04 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-H04 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-H04?
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-H04 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-H04?
C10400-H04 is rated for continuous use to about 230°C (446 °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.