CuSn5 Phosphor Bronze

Grade Designation & Standards

Standard Grade: CuSn5 (Phosphor Bronze)

International Equivalents:

• UNS (USA): C51000

• EN (Europe): CW450K

• JIS (Japan): C5101

Applicable Standards:

• GB/T 5231-2012 (Wrought Copper Alloys)

• ASTM B103 (U.S. Strip Standard)

• EN 12163 (European Standard)

Product Features

1. High Elasticity & Wear Resistance: Ideal for springs, electrical contacts, and high-cycle fatigue components.

2. Superior Corrosion Resistance: Resists atmospheric, freshwater, and seawater corrosion (corrosion rate ≤0.01 mm/a).

3. Excellent Machinability: Suitable for cold/hot working, stamping, and welding; annealing required after cold working.

4. Balanced Conductivity & Thermal Conductivity:

• Electrical Conductivity: ~15% IACS

• Thermal Conductivity: 70-80 W/(m·K)

Common Product Forms & Dimensions

Product Form	Size Range	Delivery Condition
Strip	Thickness: 0.1-2.0mm, Width ≤600mm	Soft (M), Hard (H)
Rod	Diameter: 5-150mm, Length: 2-6m	Drawn, Hot-Rolled
Wire	Diameter: 0.1-12.0mm	Coiled or Straight
Tube	OD: 3-200mm, Wall Thickness: 0.5-20mm	Soft, Half-Hard

Chemical Composition

Element	Cu	Sn	P	Pb	Impurities
Content (%)	Balance (≥94.2%)	4.5-5.5	0.1-0.4	≤0.02	≤0.2

Physical Properties

Property	Value	Remarks
Density	8.8-8.9 g/cm³	High density for precision parts
Electrical Conductivity	~15% IACS	Suitable for electrical components
Thermal Conductivity	70-80 W/(m·K)	Moderate heat dissipation
Thermal Expansion	18.5×10⁻⁶/°C (20-200°C)	Excellent thermal stability
Melting Point	1000-1020°C	Limited castability

Mechanical Properties

Property	Soft (M)	Hard (H04)
Tensile Strength (σb)	350-450 MPa	550-700 MPa
Elongation (δ10)	≥40%	≥3%
Hardness (HV)	80-150	160-220
Elastic Modulus	≥105 GPa	Critical for spring applications

Core Advantages

1. Optimal Performance Balance: High strength, elasticity, and corrosion resistance.

2. Long Service Life: Exceptional fatigue resistance (>1 million cycles).

3. Surface Treatment Compatibility: Supports plating (Ni, Ag), passivation, and coatings.

Product Applications

1. Electronics: Relay contacts, connectors, sensor springs.

2. Mechanical Engineering: Bearings, gears, wear-resistant bushings.

3. Marine Engineering: Seawater valves, pump seals (with protective coatings).

4. Automotive: Fuel injection springs, brake system components.

Processing Guidelines

1. Annealing: Post-cold working, anneal at 600-700°C to restore ductility.

2. Welding: Use TIG welding or brazing to minimize oxidation.

3. Machining: Cutting speed ≤60 m/min; use carbide tools with sulfur-based coolant.

4. Surface Preparation: Clean thoroughly before plating to ensure adhesion.

Key Application Scenarios

• High-Frequency Electrical Contacts: Switches, relays.

• Precision Mechanical Parts: Optical instrument components, watch gears.

• Corrosion-Resistant Systems: Chemical processing equipment, marine hardware.

FAQs

Q: How does CuSn5 differ from other bronzes (e.g., CuSn4)?

A: CuSn5 has higher tin content (4.5-5.5% vs. 3.5-4.5%), offering improved strength and wear resistance.

Q: Is CuSn5 suitable for saltwater environments?

A: Yes, but long-term exposure requires protective coatings (e.g., nickel plating).

Q: How to prevent cracking during cold rolling?

A: Limit single-pass deformation to ≤20% and anneal between processing stages.

Standard References

• Chemical Composition: GB/T 5231-2012, ASTM B103.

• Mechanical Testing: EN 12163, JIS H3270 (Rod Standard).

• Processing: ISO 426-2 (General manufacturing guidelines).

Note: Data consolidated from industrial standards and technical documents. Actual performance may vary slightly due to manufacturing processes. Always refer to supplier test reports for precise specifications.