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Code

Bronze

C5191 Bronze

Grade Designation & Standards

Standard Grade: C5191 (Phosphor Bronze/Tin Bronze)

International Equivalents:

China GB/T: QSn7-0.2 (GB/T 1176-1987)

USA ASTM: C51900 (UNS)

Germany DIN: CuSn8

Applicable Standards:

JIS: JIS H3110-2012 (Sheet/Strip Standards)

Others: ASTM B139, B103, B888 (Rods, Wires, etc.)

Key Features

1. High Elasticity & Wear Resistance: Tensile strength ≥470 MPa (hard state), elongation ≥13%, suitable for high-frequency friction applications (e.g., bearings, gears).

2. Superior Corrosion Resistance: Resists seawater, dilute sulfuric acid, and fatty acids (corrosion rate ≤0.01 mm/a).

3. Conductivity & Non-Magnetism: Electrical conductivity ~15.5% IACS, non-magnetic for precision electronics.

4. Workability: Supports cold/hot working, welding, and machining; plasticity restored post-annealing.

Common Product Forms & Specifications

Product Form	Size Range	Delivery Condition
Strip (C5191R)	Thickness: 0.1–5.0 mm; Width ≤600 mm	Soft (O), Hard (H), Extra-Hard (EH)
Rod	Diameter: 5–150 mm; Length: 1–6 m	Cold-drawn, Hot-rolled
Wire	Diameter: 0.1–12 mm	Coiled or Straight
Tube	OD: 3–200 mm; Wall Thickness: 0.5–20 mm	Annealed, Half-hard
Note: "R" denotes ribbon material (e.g., C5191R).

Chemical Composition

Element	Cu	Sn	P	Zn	Fe	Pb	Total Impurities
Content	Balance	6.0–7.0%	0.03–0.35%	≤0.1%	≤0.05%	≤0.02%	≤0.5%
Data Source: GB/T 1176-1987 and JIS Standards.

Physical Properties

Property	Value	Remarks
Density	8.80–8.90 g/cm³	High structural stability
Melting Point	≈900°C	Suitable for casting and high-temperature processes
Thermal Expansion Coefficient	18.5×10⁻⁶/°C (20–300°C)	Excellent dimensional stability
Electrical Conductivity	15.5–21% IACS	Superior to common copper alloys
Thermal Conductivity	38–110 W/(m·K)	Moderate heat dissipation

Mechanical Properties

Property	Annealed (O)	Hard (H)	Extra-Hard (EH)
Tensile Strength (Rm)	≥375 MPa	540–640 MPa	705–805 MPa
Elongation (A50)	≥20%	≥3%	—
Hardness (HV)	80–120	150–210	190–240
Note: Hard state (H) suits high-strength parts; EH state for extreme conditions.

Core Advantages

1. Dynamic Load Adaptability: High fatigue resistance for elastic components (e.g., springs, contacts).

2. Surface Treatment Versatility: Supports plating and passivation for enhanced corrosion resistance and aesthetics.

3. High-Temperature Stability: Operating temperature up to 250°C, ideal for high-temperature bearings.

Product Applications

Electronics: Connectors, relay springs, switch contacts, EMI shielding.
Machinery: Bearings, gears, wear-resistant bushings.
Marine & Chemical: Seawater pump components, corrosion-resistant valves.

Processing Guidelines

1. Welding: Use TIG welding with nickel-based filler (e.g., ERCuNi) to avoid porosity.

2. Machining: Carbide tools with sulfur-based coolant; cutting speed ≤80 m/min.

3. Heat Treatment:

Annealing: 700–750°C (stress relief).

Quenching: 900–950°C followed by rapid cooling (enhances hardness).

Key Application Scenarios

High-Frequency Connectors: 5G communication terminals, high-speed data interfaces.
Automotive Components: Fuel injection springs, brake seals.
Precision Instruments: Optical sensor springs, medical devices.

FAQs

Q1: How does C5191 differ from C5210?

A1: C5210 has higher tin content (7–9% vs 6–7%) for better strength and wear resistance but higher cost.

Q2: Is C5191 suitable for acidic environments?

A2: Suitable for weak acids (e.g., dilute sulfuric acid); strong acids require protective coatings.

Q3: How to prevent edge cracking in cold-rolled strips?

A3: Limit rolling reduction to ≤20% per pass, anneal post-processing, and ensure smooth rollers.

Standard References

Chemical Composition: GB/T 1176-1987, JIS H3110-2012
Mechanical Testing: ISO 6892-1 (Tensile Testing).
Processing: ASTM B139 (Rods), B103 (Strips).

Note: Data consolidated from JIS standards and industry specifications. Actual performance may vary slightly due to manufacturing processes. Refer to supplier certifications for precise details.

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