CuSn4
CW450KLow-tin phosphor bronze — the standard connector and spring material in the CuSn series. 4% Sn gives good spring properties, corrosion resistance, and electrical conductivity. Better electrical conductivity than higher-Sn bronzes. Used for connectors, contact springs, switch parts, and precision bellows. ≈ UNS C51000.
International equivalents
| Flag | Standard | Country | Grade | Number | Match |
|---|---|---|---|---|---|
| 🇺🇸 | UNS | USA | UNS C51000 (Phosphor Bronze A) | C51000 | REF |
| 🇪🇺 | EN | Europe | CuSn4 | CW450K | 100% |
Sources: ASTM B103, EN 1652
Chemical composition comparison (wt%)
Side-by-side: CuSn4 (EN 1652) vs CuSn4 (EN) (EN 1652)
| Element | CuSn4 (EN 1652) | CuSn4 (EN) | Overlap |
|---|---|---|---|
| P | — | 0.01–0.4% | — |
| Cu | — | — | — |
Mechanical properties
Compatibility verdict
CuSn4 and CuSn4: 100% composition match
Related materials
CuZn39Pb3
2.0401The most widely used free-cutting brass (machinability index 100%). Excellent for high-speed automatic lathe work. Used for turned parts, faucets, valves, fittings, screws, nuts, electrical connectors, and watch components. Also known as MS58.
CuSn8
2.1030Phosphor bronze with 8% tin. High mechanical strength, excellent wear resistance, good corrosion resistance (especially seawater). Self-lubricating sliding properties. Used for heavy-duty bearings, gears, worm wheels, springs, sliding elements, and connectors.
CuZn37
2.0321Lead-free alpha/alpha+beta brass (63% Cu, 37% Zn). Compromise between cold formability (CuZn35) and hot formability (CuZn40). The most widely used unleaded brass. Used for cartridge cases, radiator cores, lamp components, plumbing fixtures, and decorative hardware.
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