CuSn4 vs CuSn6: Adjacent phosphor bronzes — CuSn4 better conductivity, CuSn6 stronger
CuSn4 vs CuSn6
Side-by-side chemical composition and mechanical property comparison.
Overview
CuSn4
CW450K
Low-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.
CuSn6
CW452K
Phosphor bronze with 6% tin — better cold formability than CuSn8 at slightly lower strength. Excellent spring properties and fatigue resistance. Used for electrical connectors, spring contacts, switch parts, bellows, bourdon tubes, and precision springs.
| CuSn4 | CuSn6 | |
|---|---|---|
| Material Number | CW450K | CW452K |
| Category | Copper & Brass | Copper & Brass |
| Standard | EN 1652 | EN 1652 |
Chemical composition (wt%)
| Element | CuSn4 | CuSn6 | Overlap |
|---|---|---|---|
| P | 0.01–0.4% | 0.01–0.4% | OK |
| Ni | — | 0–0.3% | — |
| Cu | — | — | — |
| Sn | 3.5–4.5% | 5.5–7% | No overlap |
Mechanical properties
| Property | CuSn4 | CuSn6 | Unit |
|---|---|---|---|
| tensile_strength | 330–400 | 420–520 | MPa |
| yield_strength | 120–200 | ≥ 280 | MPa |
| elongation | 40–55 | ≥ 18 | % |
Compatibility Assessment
CuSn6 has 50% more Sn giving higher strength (UTS 500 vs 400 MPa spring) and better wear resistance. CuSn4 has better electrical conductivity (~15% IACS vs ~12%). Choose CuSn4 for connectors/electrical springs; CuSn6 for mechanical springs and bearings.
Frequently Asked Questions
Is CuSn4 the same as CuSn6?
CuSn4 and CuSn6 have a 80% composition overlap. Adjacent phosphor bronzes — CuSn4 better conductivity, CuSn6 stronger
Can I replace CuSn4 with CuSn6?
In many cases, yes. The compositions overlap significantly (80%). However, always verify mechanical property requirements and heat treatment compatibility for your specific application.
What is the difference between CuSn4 and CuSn6?
The main differences are in the following elements: Sn. CuSn4 is a Copper & Brass grade, while CuSn6 is a Copper & Brass grade.
Related Comparisons
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Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.