Copper Alloy C10700-H04
Supply condition
UNS C10700 · EN CW019A
H04 = full hard
Standard hard temper for busbar, commutator segments and stiff stamped conductors that see soldering heat.
Values for the H04 condition
Other C10700 tempers and conditions
C10700 is listed in 11 conditions; see the grade overview at C10700.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled and annealed | Plate/bar softened after hot rolling for maximum conductivity and bending of heavy busbar sections. | 69 | 220 | 45 | 45 HB | 101 % IACS |
Soft annealed | Maximum ductility and conductivity for deep drawing, bending and coil winding. | 70 | 225 | 45 | 45 HB | 101 % IACS |
As hot rolled | Cheapest mill condition for busbar and plate that will be machined or formed rather than used at final strength. | 90 | 235 | 42 | 50 HB | 100.5 % IACS |
1/8 hard | Slight stiffening over annealed while keeping near-full drawability; used for formed contacts and shielding. | 170 | 250 | 30 | 60 HB | 100.5 % IACS |
Quarter hard | Balanced temper for stamped parts needing moderate bends and some springback control. | 205 | 262 | 25 | 68 HB | 100 % IACS |
H02Default Half hard | Most-stocked strip/sheet temper: useful strength with enough ductility for 90° bends and riveting. | 250 | 290 | 14 | 75 HB | 100 % IACS |
Three-quarter hard | Higher strength for flat parts with gentle forming only; good stiffness for commutator and terminal stock. | 280 | 315 | 8 | 85 HB | 99.5 % IACS |
H04This page Full hard | Standard hard temper for busbar, commutator segments and stiff stamped conductors that see soldering heat. | 310 | 345 | 6 | 95 HB | 99 % IACS |
Extra hard | Near-maximum rolled strength where only flat blanking or very light forming follows. | 340 | 365 | 4 | 100 HB | 98.5 % IACS |
Spring hard | Spring-rolled strip for contact fingers and clips that must keep force after soldering — the classic reason to specify the silver-bearing grade. | 355 | 380 | 4 | 105 HB | 98 % IACS |
Extra spring hard | Maximum cold-rolled hardness for thin spring strip and shims; minimal bendability, plan generous bend radii along grain. | 370 | 395 | 3 | 110 HB | 97.5 % IACS |
What is C10700-H04?
C10700-H04 is C10700 supplied in the H04 condition — standard hard temper for busbar, commutator segments and stiff stamped conductors that see soldering heat. C10700-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). C10700-H04 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,083°C (1,981 °F). H02 is the default condition FabDigit quotes; H04 is available on request or by drawing note.
Advantages
- High electrical conductivity — 99 % IACS, better than 95% of copper alloy grades
- Conducts heat well — 386 W/m·K (223 BTU/hr·ft·°F), better than 93% of copper alloy grades
- Polishes to a fine finish — 85/100, better than 92% of copper alloy grades
- Readily welded — 60/100, better than 76% of copper alloy grades
Limitations
- Limited ductility — 6%, worse than 89% of copper alloy grades
C10700-H04 properties
Typical room-temperature values for C10700-H04; 15 are specific to this condition. Other listed values are C10700 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C10700-H04 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,083°C (1,981 °F).
Mechanical13
C10700-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
C10700-H04 is rated for continuous service to 250°C (482 °F). It conducts heat at 386 W/m·K (223 BTU/hr·ft·°F), better than 93% of copper alloy grades. Thermal expansion is 17.7 µm/m·K (9.83 µin/in·°F).
Electrical3
C10700-H04 conducts electricity at 99 % IACS, better than 95% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C10700-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 30%.
Manufacturability7
C10700-H04's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability good (60/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C10700-H04
Is C10700 easy to machine?
Gummy and low-rated (~20 % of AISI 1212): use sharp positive-rake tools, high speed, light feeds and generous coolant; harder tempers (H04+) cut and chip-break better than annealed.
Can C10700 be welded?
Excellent by GTAW/GMAW with argon-helium and preheat on thick sections, also EB and resistance welding; avoid oxyacetylene and avoid contaminating the oxygen-free chemistry — the HAZ will anneal but Ag delays softening.
Can C10700 be formed, bent or molded?
Very ductile in O60/H00 (deep draw, spin, cold head); half-hard bends readily to 1t, spring tempers need generous radii and bending across the rolling direction.
What surface finishes work on C10700?
Not anodizable; solders and brazes exceptionally well, takes bright Ni/Ag/Sn plating and high polish, but bare surfaces tarnish and need lacquer or passivation.
C10700 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≈25 troy oz per short ton; raises softening resistance | ≥ 0.09 | 0.1 |
| O10 ppm max, typical <5 ppm | ≤ 0 | 5×10⁻⁴ |
| Presidual limit per ASTM B170 class-type OF chemistry | ≤ 3×10⁻⁴ | — |
| Bi | ≤ 5×10⁻⁴ | — |
| Pb | ≤ 5×10⁻⁴ | — |
| S | ≤ 0 | — |
| Se | ≤ 3×10⁻⁴ | — |
| Te | ≤ 2×10⁻⁴ | — |
| CuCu + Ag ≥ 99.95 %; oxygen-free (no deoxidizer residue) | ≥ 99.95 (balance) | — |
C10700-H04 — frequently asked
What is C10700-H04 used for?
C10700-H04 is typically used for contact springs, commutators and resistance welding components. In short: silver-modified oxygen-free copper; softening resistance during soldering; 100 % IACS with spring tempers.
What is the yield strength of C10700-H04?
C10700-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 11 listed tempers.
Is C10700-H04 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Gummy and low-rated (~20 % of AISI 1212): use sharp positive-rake tools, high speed, light feeds and generous coolant; harder tempers (H04+) cut and chip-break better than annealed.
Can C10700-H04 be welded?
Yes — weldability is rated good (60/100). Excellent by GTAW/GMAW with argon-helium and preheat on thick sections, also EB and resistance welding; avoid oxyacetylene and avoid contaminating the oxygen-free chemistry — the HAZ will anneal but Ag delays softening.
What surface finishes work on C10700-H04?
Not anodizable; solders and brazes exceptionally well, takes bright Ni/Ag/Sn plating and high polish, but bare surfaces tarnish and need lacquer or passivation.
Can C10700-H04 be formed, bent or molded?
Very ductile in O60/H00 (deep draw, spin, cold head); half-hard bends readily to 1t, spring tempers need generous radii and bending across the rolling direction.
What is the maximum service temperature of C10700-H04?
C10700-H04 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C10700-H02 and C10700-O25?
H02 is the default condition — most-stocked strip/sheet temper: useful strength with enough ductility for 90° bends and riveting. O25: plate/bar softened after hot rolling for maximum conductivity and bending of heavy busbar sections. Yield strength is 250 MPa in H02 versus 69 MPa in O25.
Sources
- ASTM B152/B152M — Copper Sheet, Strip, Plate and Rolled Bar — ASTM International (2019)
- ASTM B170 — Oxygen-Free Electrolytic Copper Refinery Shapes — ASTM International (2019)
- EN 13601 / CW019A (Cu-OFS) wrought copper for electrical purposes — CEN (2021)
- CDA Alloy Datasheet C10700 (Oxygen-Free with Silver) — 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.