Copper Alloy C10700-O25
Temper
UNS C10700 · EN CW019A
O25 = hot rolled and annealed
Plate/bar softened after hot rolling for maximum conductivity and bending of heavy busbar sections.
Values for the O25 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 |
|---|---|---|---|---|---|---|
O25This page 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 |
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-O25?
C10700-O25 is C10700 in the O25 temper — plate/bar softened after hot rolling for maximum conductivity and bending of heavy busbar sections. C10700-O25 has a yield strength of 69 MPa (10 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 96% of copper alloy grades. Elongation at break is 45% and the elastic modulus is 117 GPa (17 Msi). C10700-O25 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; O25 is available on request or by drawing note.
Advantages
- Conducts heat well — 391 W/m·K (225.9 BTU/hr·ft·°F), better than 98% of copper alloy grades
- High electrical conductivity — 101 % IACS, better than 98% of copper alloy grades
- Forms and bends easily — 97/100, better than 97% of copper alloy grades
- Polishes to a fine finish — 85/100, better than 92% of copper alloy grades
- Ductile — tolerates forming and impact — 45%, better than 91% of copper alloy grades
Limitations
- Low strength — 69 MPa (10 ksi), worse than 96% of copper alloy grades
C10700-O25 properties
Typical room-temperature values for C10700-O25; 12 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-O25 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-O25 has a yield strength of 69 MPa (10 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 96% of copper alloy grades. Elongation at break is 45% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C10700-O25 is rated for continuous service to 300°C (572 °F). It conducts heat at 391 W/m·K (225.9 BTU/hr·ft·°F), better than 98% of copper alloy grades. Thermal expansion is 17.7 µm/m·K (9.83 µin/in·°F).
Electrical3
C10700-O25 conducts electricity at 101 % IACS, better than 98% 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-O25 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-O25's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability good (60/100); formability excellent (97/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C10700-O25
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-O25 — frequently asked
What is C10700-O25 used for?
C10700-O25 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-O25?
C10700-O25 has a typical yield strength of 69 MPa (10 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 96% of copper alloy grades. Strength varies by condition: see the 11 listed tempers.
Is C10700-O25 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-O25 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-O25?
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-O25 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-O25?
C10700-O25 is rated for continuous use to about 300°C (572 °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.