CuNi2Si
2.0855Nickel-silicon precipitation-hardened copper alloy combining high strength (UTS ~700 MPa aged) with good electrical conductivity (35–45% IACS) and excellent stress relaxation resistance at elevated temperatures. Lead-free and RoHS compliant — the modern replacement for CuBe2 in many connector applications where beryllium toxicity is a concern. Trade names: Wieland K55 (Wieland), C70250 (Olin Brass). Used for automotive high-current connectors, IC lead frames, relay springs, fuse clips and miniaturized electronic contacts.
International equivalents
| Flag | Standard | Country | Grade | Number | Match |
|---|---|---|---|---|---|
| 🇺🇸 | UNS | USA | C70250 | C70250 | REF |
| 🇪🇺 | EN | Europe | CW109C | — | 100% |
Sources: ASTM B534, EN 12163
Mechanical properties — Pro
Solution annealed
| Property | Value | Unit |
|---|---|---|
| Tensile Strength |
Precipitation hardened
| Property | Value | Unit |
|---|---|---|
| Tensile Strength | ||
| Yield Strength Rp0.2 | ||
| Elongation A |
General
| Property | Value | Unit |
|---|---|---|
| Density | ||
| Electrical Conductivity | ||
| Thermal Conductivity |
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