Copper Alloy C70260-TM00
Precip hard
UNS C70260 · EN CW111C, CuNi2Si
TM00 = mill hardened
Pick when deep forming, tight bends or complex stamping dominate and moderate spring force is enough.
Values for the TM00 condition
Other C70260 tempers and conditions
C70260 is listed in 5 conditions; see the grade overview at C70260.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
TM00This page 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-TM00?
C70260-TM00 is C70260 in the TM00 condition — pick when deep forming, tight bends or complex stamping dominate and moderate spring force is enough. C70260-TM00 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 490 MPa (71.1 ksi) — stronger than 80% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 130 GPa (18.9 Msi). C70260-TM00 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). TM02 is the default condition FabDigit quotes; TM00 is available on request or by drawing note.
Advantages
- Stiff — 130 GPa (18.9 Msi), better than 89% of copper alloy grades
- Forms and bends easily — 80/100, better than 83% of copper alloy grades
- High strength — 400 MPa (58 ksi), better than 80% of copper alloy grades
- High electrical conductivity — 53 % IACS, better than 80% of copper alloy grades
- Conducts heat well — 200 W/m·K (115.6 BTU/hr·ft·°F), better than 78% of copper alloy grades
C70260-TM00 properties
Typical room-temperature values for C70260-TM00; 13 are specific to this condition. Other listed values are C70260 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C70260-TM00 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-TM00 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 490 MPa (71.1 ksi) — stronger than 80% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 130 GPa (18.9 Msi).
Thermal6
C70260-TM00 is rated for continuous service to 200°C (392 °F). It conducts heat at 200 W/m·K (115.6 BTU/hr·ft·°F), better than 78% of copper alloy grades. Thermal expansion is 17.6 µm/m·K (9.78 µin/in·°F).
Electrical3
C70260-TM00 conducts electricity at 53 % IACS, better than 80% 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-TM00 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-TM00's machinability is poor (34/100, worse than 53% of copper alloy grades); weldability fair (45/100); formability very good (80/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C70260-TM00
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.
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.
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 | — |
C70260-TM00 — frequently asked
What is C70260-TM00 used for?
C70260-TM00 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-TM00?
C70260-TM00 has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 490 MPa (71.1 ksi) — stronger than 80% of copper alloy grades. Strength varies by condition: see the 5 listed tempers.
Is C70260-TM00 easy to machine?
Not especially — machinability is rated poor (34/100, worse than 53% 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-TM00 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-TM00?
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-TM00 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-TM00?
C70260-TM00 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.