1. Material Definition and Classification

C61900 is an aluminum bronze alloy classified under the U.S. Unified Numbering System (UNS), primarily strengthened by adding elements like aluminum (Al), iron (Fe), and manganese (Mn). It offers a combination of high strength, wear resistance, and corrosion resistance, making it a critical material in industrial applications.

2.Chemical Composition (wt%)

• Cu：86–89%

Base metal providing electrical and thermal conductivity

• Al：8.5–10%

Forms hard, brittle phases (e.g., CuAl₂) to enhance strength, hardness, and corrosion resistance

• Fe：≤2.5%

Refines grain structure, improving wear resistance and mechanical properties

• Mn：≤2.0%

Enhances corrosion resistance and processing properties, inhibits oxidation of aluminum

• Impurities：≤0.5%

Traces of other elements

3. Physical and Mechanical Properties

(1)Physical Properties

• Density: Approximately 7.6–7.8 g/cm³ (lighter than steel, heavier than common brass)

• Melting Point: Approximately 980–1040°C (slightly variable depending on composition)

• Electrical Conductivity: About 10% IACS (lower than pure copper but superior to most structural steels)

(2)Mechanical Properties (Varies with Heat Treatment State)

• Annealed State (O)

Tensile Strength:≥630 MPa

Yield Strength:≥245 MPa (0.2%)

Elongation:≥12%

Hardness:≥180 HB

• Quenched + Tempered (H)

Tensile Strength:≥850 MPa

Yield Strength:≥550 MPa (0.2%)

Elongation:≥8%

Hardness:≥250 HB (can be adjusted through heat treatment)

• Characteristics: Strength comparable to low-alloy steel, toughness superior to common bronzes, high fatigue limit, suitable for dynamic loading environments.

4. Core Features and Advantages

（1）High Strength and Wear Resistance

The precipitation-hardening mechanism unique to aluminum bronze makes it excellent for high-load, high-friction environments such as gears and bearings, with wear resistance far superior to brass.

（2）Exceptional Corrosion Resistance

• Seawater Corrosion Resistance: Excellent resistance to pitting and stress corrosion in marine environments, often used for ship parts.

• Chemical Resistance: Resistant to acids (e.g., acetic acid, dilute sulfuric acid) and salt fog, suitable for chemical equipment.

（3）Good Processability

• Castability: Good fluidity, suitable for sand casting and metal mold casting, can produce complex-shaped parts (e.g., pump bodies, valve bodies).

• Machinability: After annealing, it has good machinability (requires high-speed steel or carbide tools), moderate cold workability, and a hot-working temperature range of 750–950°C.

（4）High-Temperature and Oxidation Resistance

Retains mechanical properties at 300–400°C, with a surface oxide layer (Al₂O₃) forming to prevent high-temperature oxidation.

5.Typical Application Fields

（1）Mechanical Engineering

Gears, worm gears, bearings, bearing sleeves, slides (high-load, wear-resistant components)

（2）Marine and Ocean Engineering

Seawater pump impellers, propeller shafts, valves, heat exchanger tube plates (seawater corrosion resistance)

（3）Chemicals and Petrochemicals

Corrosion-resistant valves, pipeline joints, reactor stirrers (acid/salt corrosion resistance)

（4）Aerospace

Engine supports, hydraulic system components (high strength + lightweight)

（5）Energy

Nuclear power valves, wind turbine gearbox bearings (long lifespan, high reliability)

6. Processing and Heat Treatment Processes

（1）Heat Treatment Processes

• Annealing (Stress Relief): Heat to 650–750°C for 1–2 hours, air-cool to improve plasticity and machinability.

• Quenching + Tempering:

Quenching: Heat to 900–950°C, water-cool (rapid cooling forms martensite-like structure, greatly increasing hardness).

Tempering: Heat to 300–500°C to adjust strength and toughness (low-temperature tempering focuses on hardness, high-temperature tempering focuses on toughness).

• Aging Treatment: After quenching, age at 150–300°C to promote uniform distribution of precipitates, further enhancing strength.

（2）Machining Considerations

• Cutting: Use sulfur-containing cutting fluids; increase tool rake angle to reduce cutting force.

• Welding: Use oxy-acetylene or TIG welding with aluminum-containing copper alloy filler (e.g., ERCuAl-A2), preheat to 300–400°C to avoid porosity and cracking.

7.Limitations and Improvements

• Brittleness Risk: When aluminum content exceeds 11%, the formation of α+γ2 phases leads to brittleness. C61900 balances strength and toughness by controlling Al content to 8.5–10%.

• Cost: Higher raw material costs compared to brass and regular bronze, making it suitable for demanding applications.

• Alternative Materials: For lower wear resistance, choose cost-effective tin bronzes (e.g., C51000); for higher corrosion resistance, consider nickel-aluminum bronze (e.g., C95800).

8. Standards and Specifications

• U.S. Standards: ASTM B148 (Aluminum bronze castings), ASTM B150/B150M (Aluminum bronze bars/rods).

• China Standards: GB/T 4423 (Copper and copper alloy drawn rods), GB/T 1176 (Cast copper alloys).

9. Selection and Testing

• Quality Control: Focus on testing chemical composition (spectral analysis), mechanical properties (tensile/hardness tests), and metallographic structure (to avoid overburning or segregation).

• Supplier Selection: Prefer manufacturers certified by IATF 16949 to ensure controllable heat treatment processes and stable performance.

10. Conclusion

C61900 aluminum bronze, with its combination of “copper’s toughness, steel’s strength, and excellent corrosion resistance,” is a key material in high-end equipment manufacturing, particularly in harsh environments. Its performance can be precisely controlled through composition tuning and heat treatment, meeting a wide range of industrial needs.

11. Choose Bolaibao for Your Material Needs

As a professional copper alloy materials provider, Suzhou Bolaibao Metal Group is committed to supplying high-performance, stable-quality aluminum bronze materials, including C61900. We offer long-term stock supply, custom processing, material certification, and fast delivery services.

We are not just a material supplier, but your reliable partner for metal solutions.

Visit our website for more product information: www.blbmetal.com
Business inquiries: sale@bolaibao1.com
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