QSn8-0.3 Bronze

Designation and Standards

• Standard Designation: QSn8-0.3 (Phosphor Bronze)

• Implementing Standards: GB/T 5231-2012 (Wrought Copper and Copper Alloys), GB/T 4423-2007 (Bars)

• International Equivalent Grades: ASTM C52100, EN CuSn8 (EN 12163), JIS C5210

• Material Category: Copper-Tin-Phosphorus Alloy (Cu-Sn-P), Tin content 7.0%-9.0%, Phosphorus content 0.1%-0.3%, Copper balance.

Product Characteristics

• Ultra-High Strength and Elasticity:

  Tensile strength ≥550 MPa, elastic limit ≥600 MPa, suitable for high-load elastic components (e.g., precision springs).

• Exceptional Wear Resistance:

  Hardness (HV 150-250) significantly higher than bronzes with low tin content, wear resistance comparable to beryllium bronze, but at a lower cost.

• Excellent Corrosion Resistance:

  Resistant to atmospheric, seawater, and weak acid corrosion (corrosion rate ≤0.003 mm/a), with no tendency for stress corrosion cracking.

• Good Working Adaptability:

  Good cold/hot working performance; coldworking requires strict deformation control (≤20%), followed by annealing to restore plasticity.

Chemical Composition

Physical Properties

Mechanical Properties

Common Product Forms and Specifications

Core Application Fields

• Aerospace:

  Flight control systems: Servo spring, hydraulic valve plates (fatigue and high-pressure resistance).

  Engine components: Turbine seals (high-temperature wear resistance).

• High-End Electronics:

  Semiconductor packaging: Probe card springs, chip test contacts (high-precision elastic contact).

• Medical Devices:

  Implantable devices: cardiacpacemaker springs (biocompatibility and long life).

• Energy Industry:

  Nuclear power plant equipment: Radiation-resistant valve springs, sealing components.

Processing Considerations

• Annealing Process:

  After cold working, anneal at 680-750°C for 1-2 hours to prevent grain coarsening.

• Welding Requirements:

  Preferably use electron beam welding or laser welding to reduce brittleness in the heat-affected zone; for soldering and brazing, silver-based solder (melting point 600-800°C) is recommended.

• Surface Treatment:

  Gold/palladium plating to improve conductivity, or DLC coating (i-carbon) to enhance wear resistance.

• Cutting Parameters:

  Cutting speed ≤40 m/min, use carbide tools, and use cooling fluids containing extreme pressure additives.

Frequently Asked Questions

Q: What is the difference between QSn8-0.3 and QSn6.5-0.1?

A: QSn8-0.3 has a higher tin content (7%-9% vs. 6%-7%), providing superior elasticity and wear resistance, but it is more difficult to process and costs more.

Q: Is it suitable for long-term use in high-temperature environments?

A: It is recommended for long-term use at temperatures ≤180°C, with short-term tolerance up to 300°C; it will anneal significantly above 350°C.

Q: How can edge cracking be avoided during cold rolling of strips?

A: Control the deformation per pass (≤15%), pre-treat for stress relief before annealing, and polish the roller surface to Ra ≤0.2μm.

Standards References

• Chemical Composition and Processing Specifications: GB/T 5231-2012, GB/T 4423-2007 (Bars).

• International Standards: ASTM B103 (American standard for strips), EN 12163 (European Standard), JIS H3270 (Japanese standard for bars).

Note: The above data is based on national standards and industry technical documents. Actual performance may vary slightly due to production processes, and specific values should be verified with the supplier's test report.