C70250 Copper Alloy Strip (CuNi3SiMg / C7025)
C70250 is a Ni-Si-Mg age-hardening (precipitation-strengthened) high-performance copper alloy strip. Precipitation of the fine NiSi phase gives it an outstanding combination of high strength (up to 1000 MPa), good electrical conductivity (≈40% IACS) and excellent stress-relaxation resistance — making it a leading material for miniaturized, high-reliability automotive and electronic connectors.
Key Features & Advantages
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High strength + conductivity balance — tensile strength up to 900–1000 MPa while retaining ~40% IACS conductivity.
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Superior stress-relaxation resistance — holds contact force at elevated temperature, ideal for under-hood connectors.
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Excellent bendability for tight-radius stamping and forming.
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Good solderability & plateability (Sn, Ni, Au).
- Stable spring properties for terminals, contacts and lead frames.
Typical Applications
- Automotive & new-energy-vehicle connectors and terminals
- Lead frames for IC / semiconductor packaging
- Spring contacts, relays and precision stamped parts
- High-density board-to-board and signal connectors
Equivalent Grades
| ASTM |
EN |
JIS |
| C70250 |
CuNi3SiMg |
C7025 |
Chemical Composition (%)
| Cu |
Ni |
Si |
Mg |
Zn |
| Balance |
2.2–4.2 |
0.25–1.2 |
0.05–0.30 |
≤1.0 |
Physical Properties
| Density (g/cm³) |
Modulus (GPa) |
Thermal Exp. (×10⁻⁶/K) |
Conductivity (%IACS) |
Thermal Cond. (W/m·K) |
| 8.8 |
130 |
17.6 |
40 |
190 |
Mechanical Properties (by Temper)
| Temper |
Tensile Rm (MPa) |
Yield (MPa) |
Elong. % (A50) |
Hardness HV |
| TM00 |
620–760 |
≥550 |
≥14 |
180–220 |
| TM02 |
655–780 |
≥585 |
≥8 |
190–240 |
| TM03 |
690–810 |
≥655 |
≥7 |
210–250 |
| TM04 |
760–850 |
≥720 |
≥2 |
220–270 |
| TM06 |
800–880 |
≥780 |
≥1 |
250–290 |
| TM08 |
840–920 |
≥810 |
≥1 |
270–330 |
| TM10 |
900–1000 |
≥880 |
— |
300–350 |
Available Sizes
Thickness 0.05–2.0 mm · Width slit to customer requirement · Supplied in coil or cut sheet.
Need C70250 (CuNi3SiMg) strip for your connectors or lead frames?Custom temper, thickness and width — free samples & datasheet on request.
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FAQ
Q: What is C70250 copper used for?
C70250 (CuNi3SiMg / C7025) is mainly used for automotive connectors, terminals, spring contacts and IC lead frames that require high strength with stable conductivity and stress-relaxation resistance.
Q: What is the conductivity of C70250?
Approximately 40% IACS, combined with a tensile strength of up to ~1000 MPa in the high tempers.
Q: Which grades are equivalent to C70250?
EN CuNi3SiMg and JIS C7025 are the equivalent international designations.
Q: Can you supply samples of C70250 strip?
Yes. Shanghai Xinye Metal supplies samples and full mill test certificates; thickness, temper and width are made to order.
EN
