Copper Alloy C70260
UNS C70260 · EN CW111C, CuNi2Si
C70260 (CW111C, CuNi2Si) is a precipitation-hardening copper-nickel-silicon strip alloy, more lightly alloyed than C70250, supplied mill-hardened in TM00 through TM04.
Reference datasheet — C70260 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the TM02 condition
C70260 tempers and conditions
C70260 is supplied in 5 conditions, soft to hard. TM02 is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Mill hardened | Pick when deep forming, tight bends or complex stamping dominate and moderate spring force is enough. | 400 | 490 | 15 | 79 HRB | 53 % IACS |
Mill hardened, low-intermediate strength | Use for stamped contacts needing better spring force than TM00 while keeping generous bend radii. | 480 | 550 | 12 | 85 HRB | 51 % IACS |
TM02Default Mill hardened, half hard | The default stocked strip temper: balanced spring force, formability and ~50% IACS conductivity. | 535 | 595 | 9 | 89 HRB | 50 % IACS |
Mill hardened, high strength | Choose for higher contact normal force and better stress relaxation, accepting larger minimum bend radii. | 580 | 630 | 7 | 93 HRB | 48 % IACS |
Mill hardened, full hard | Top mill-hardened level for maximum spring force and relaxation resistance in shallow-formed parts. | 620 | 665 | 5 | 96 HRB | 46 % IACS |
What is C70260?
C70260 (CW111C, CuNi2Si) is a precipitation-hardening copper-nickel-silicon strip alloy, more lightly alloyed than C70250, supplied mill-hardened in TM00 through TM04. Typical mill-hardened properties are 535 MPa yield, 595 MPa tensile, 9 % elongation and 89 HRB with 50 % IACS and 190 W/m·K, which gives spring contacts adequate force with good current-carrying ability. Service is limited to about 200 °C, machinability is 38 and fusion welding over-ages the temper, so it is used mainly in stamped and formed strip parts; C70250 is the higher-strength alternative and C51000 phosphor bronze the lower-conductivity one. C70260 has a density of 8.83 g/cm³ (0.319 lb/in³), heavier than 65% of copper alloy grades. It melts at 1,085°C (1,985 °F). C70260 has a yield strength of 535 MPa (77.6 ksi) and a tensile strength of 595 MPa (86.3 ksi) — stronger than 91% of copper alloy grades. Elongation at break is 9% and the elastic modulus is 130 GPa (18.9 Msi).
What is C70260 used for?
- connectors
- lead frames
- switch parts
- terminals
Advantages
- High strength — 535 MPa (77.6 ksi), better than 91% of copper alloy grades
- Stiff — 130 GPa (18.9 Msi), better than 89% of copper alloy grades
- High electrical conductivity — 50 % IACS, better than 79% of copper alloy grades
- Forms and bends easily — 65/100, better than 78% of copper alloy grades
- Conducts heat well — 190 W/m·K (109.8 BTU/hr·ft·°F), better than 77% of copper alloy grades
Limitations
- Limited ductility — 9%, worse than 79% of copper alloy grades
C70260 properties
Typical room-temperature values for C70260-TM02; bars are the position among copper alloy grades.
Physical3
C70260 has a density of 8.83 g/cm³ (0.319 lb/in³), heavier than 65% of copper alloy grades. It melts at 1,085°C (1,985 °F).
Mechanical12
C70260 has a yield strength of 535 MPa (77.6 ksi) and a tensile strength of 595 MPa (86.3 ksi) — stronger than 91% of copper alloy grades. Elongation at break is 9% and the elastic modulus is 130 GPa (18.9 Msi).
Thermal6
C70260 is rated for continuous service to 200°C (392 °F). It conducts heat at 190 W/m·K (109.8 BTU/hr·ft·°F), better than 77% of copper alloy grades. Thermal expansion is 17.6 µm/m·K (9.78 µin/in·°F).
Electrical3
C70260 conducts electricity at 50 % IACS, better than 79% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C70260 takes about 60 MJ of energy and emits 4 kg of CO₂ — more than 69% of copper alloy grades. Typical recycled content is 35%.
Manufacturability7
C70260's machinability is fair (38/100, better than 55% of copper alloy grades); weldability fair (45/100); formability good (65/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C70260 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C70260
Is C70260 easy to machine?
Machines like a medium-hard bronze — chips are gummy; use sharp carbide, positive rake and generous coolant; rating ≈30 % of AISI 1212.
Can C70260 be welded?
Resistance and laser welding are practical; fusion welding locally over-ages the strip and loses spring temper, so avoid on formed contacts.
Can C70260 be formed, bent or molded?
Mill-hardened strip stamps and bends well in TM00–TM02 (good-way bends near 0–1t); step up bend radii and prefer good-way orientation at TM03/TM04.
C70260 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 |
|---|---|---|
| Ni | 1.6 – 2.5 | 2 |
| Si | 0.4 – 0.8 | 0.55 |
| Mgoptional micro-addition for relaxation resistance | ≤ 0.15 | |
| Fe | ≤ 0.2 | |
| Zn | ≤ 0.5 | |
| Mn | ≤ 0.1 | |
| Pb | ≤ 0.02 | |
| Others (total) | ≤ 0.3 | |
| Cu≈96.5 % nominal | balance |
What surface finishes work on C70260?
Not anodizable; standard finishes are Sn, Sn-Pb-free reflow, Ni underplate with Au or Ag flash for contacts; degrease and micro-etch before plating.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Equivalent designations
Standards and trade names that resolve to Copper Alloy C70260 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- CW111CCuNi2Si
How much does C70260 cost?
C70260 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C70260 — frequently asked
What is C70260 used for?
C70260 is typically used for connectors, lead frames, switch parts and terminals. In short: balanced conductivity and spring force; formable Cu-Ni-Si strip; lower-alloy C70250 alternative.
What is the yield strength of C70260?
C70260 has a typical yield strength of 535 MPa (77.6 ksi) and a tensile strength of 595 MPa (86.3 ksi) — stronger than 91% of copper alloy grades. Strength varies by condition: see the 5 listed tempers.
Is C70260 easy to machine?
Not especially — machinability is rated fair (38/100, better than 55% of copper alloy grades). Machines like a medium-hard bronze — chips are gummy; use sharp carbide, positive rake and generous coolant; rating ≈30 % of AISI 1212.
Can C70260 be welded?
With care — weldability is rated fair (45/100). Resistance and laser welding are practical; fusion welding locally over-ages the strip and loses spring temper, so avoid on formed contacts.
What surface finishes work on C70260?
Not anodizable; standard finishes are Sn, Sn-Pb-free reflow, Ni underplate with Au or Ag flash for contacts; degrease and micro-etch before plating.
Can C70260 be formed, bent or molded?
Mill-hardened strip stamps and bends well in TM00–TM02 (good-way bends near 0–1t); step up bend radii and prefer good-way orientation at TM03/TM04.
What is the maximum service temperature of C70260?
C70260 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C70260-TM02 and C70260-TM00?
TM02 is the default condition — the default stocked strip temper: balanced spring force, formability and ~50% IACS conductivity. TM00: pick when deep forming, tight bends or complex stamping dominate and moderate spring force is enough. Yield strength is 535 MPa in TM02 versus 400 MPa in TM00.
How much does C70260 cost?
C70260 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- EN 1654 / EN 1652 — Copper and copper alloys, strip for springs and connectors (CW111C CuNi2Si) — CEN (2019)
- ASTM B888 — Copper Alloy Strip for Electrical Connectors and Lead Frames — ASTM (2020)
- UNS C70260 alloy data — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Cu-Ni-Si mill-hardened connector strip datasheets (TM00–TM04) — Various strip producers (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.