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China Bronze CNC Machining Services - Reliable Suppliers & Factory for High-Performance Industrial Parts
Bronze typically refers to a family of alloys with copper as the base, primarily alloyed with elements such as tin, aluminum, silicon, and manganese. Compared to brass (copper-zinc alloys), bronze generally offers higher strength, a lower coefficient of friction, and better chemical corrosion resistance (especially against seawater). Its outstanding wear resistance and self-lubricating properties make it irreplaceable in bearing and bushing applications.
1 C93200 / SAE 660 (High-Leaded Tin Bronze - Bearing Bronze)
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Characteristics: This is the most widely used bearing bronze. The added lead forms soft particles within the alloy, providing excellent self-lubricating and anti-galling properties, making it ideal for operation under insufficient lubrication or high-load, low-speed conditions. It is easy to machine and offers good wear resistance.
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Typical Applications: General-purpose bearings, bushings, thrust washers, pump components, low-load gears.
📋 C93200 Typical Properties (As Sand-Cast)
| Property | Value | Notes |
|---|---|---|
| Tensile Strength (MPa) | 240 – 330 | Good overall strength |
| Yield Strength (0.5% Extension, MPa) | 124 | |
| Elongation at Break (%) | 18 | Good ductility |
| Hardness (Brinell) | 65 | |
| Density (g/cm³) | 8.93 | |
| Key Composition | Cu-83%, Sn-7%, Pb-7%, Zn-3% | High lead content provides self-lubrication |
| Note: Values are typical ranges, specific to casting and processing conditions. | ||
2 C95400 (Aluminum Bronze)
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Characteristics: A high-strength, high-hardness aluminum bronze. Its corrosion resistance, wear resistance, and fatigue strength are among the best of all bronzes, with performance comparable to many steels. It retains strength at elevated temperatures and offers excellent impact and cavitation resistance.
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Typical Applications: Heavy-duty bearings, gears, valve seats, pump housings, propellers and components for seawater use, chemical processing equipment.
📋 C95400 Typical Properties (Heat-Treated Condition)
| Property | Value | Notes |
|---|---|---|
| Tensile Strength (MPa) | 620 – 760 | Very high strength, comparable to low-alloy steels |
| Yield Strength (0.2% Offset, MPa) | 275 | |
| Elongation at Break (%) | 12–18 | |
| Hardness (Brinell) | 170 – 210 | High hardness, very wear-resistant |
| Density (g/cm³) | 7.45 | Lighter than tin bronze |
| Key Composition | Cu-85%, Al-11%, Fe-4% | Tin-free, uses aluminum and iron as main alloying elements |
| Note: Values are typical ranges, specific to heat treatment condition. | ||
3 C54400 (Phosphor Bronze)
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Characteristics: A tin bronze containing a small amount of phosphorus. Phosphorus increases the alloy's elastic limit, fatigue strength, and wear resistance. This material offers excellent spring properties, good wear and corrosion resistance, and is easily machined into precision parts.
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Typical Applications: Electrical connectors, springs, diaphragms, bellows, wear plates, precision gears.
📋 C54400 Typical Properties (Cold Worked Condition)
| Property | Value | Notes |
|---|---|---|
| Tensile Strength (MPa) | 520 – 690 | High strength, especially suitable for elastic elements |
| Yield Strength (0.2% Offset, MPa) | 380 – 550 | High yield strength |
| Elongation at Break (%) | 10–15 | |
| Hardness (Rockwell B) | 78 – 90 | |
| Density (g/cm³) | 8.8 | |
| Key Composition | Cu-88%, Sn-4%, Zn-4%, P-0.2–0.5% | Phosphorus acts as a deoxidizer and enhances properties |
| Note: Values are typical ranges, specific to the degree of cold work. | ||
4 C65500 (High-Silicon Bronze)
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Characteristics: A bronze with excellent corrosion resistance, particularly outstanding in sulfuric acid and sulfate environments. It combines high strength, high corrosion resistance, and good formability and weldability, making it widely used in chemical and marine industries.
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Typical Applications: Chemical processing equipment components, heat exchanger tube sheets, marine fittings, pump valves, fasteners, welded structures.
❓ Frequently Asked Questions
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What is the most commonly used bronze alloy for bearing applications?
C93200 (SAE 660), also known as High-Leaded Tin Bronze, is the most widely used bearing bronze. Its high lead content creates soft particles within the alloy matrix that provide excellent self-lubricating and anti-galling properties, making it ideal for bearings, bushings, and thrust washers — especially under high-load, low-speed, or insufficient lubrication conditions.
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How does aluminum bronze (C95400) compare to steel in terms of strength?
C95400 Aluminum Bronze offers a tensile strength of 620–760 MPa in its heat-treated condition, which is comparable to many low-alloy steels. In addition to its high strength, it provides superior corrosion resistance, excellent fatigue and impact resistance, and retains its mechanical properties at elevated temperatures — making it a strong alternative to steel in demanding environments.
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What role does phosphorus play in C54400 Phosphor Bronze?
Phosphorus in C54400 serves two key functions: it acts as a deoxidizer during casting, improving the alloy's cleanliness and soundness, and it significantly enhances the material's elastic limit, fatigue strength, and wear resistance. These properties make Phosphor Bronze particularly well-suited for springs, electrical connectors, diaphragms, and other precision components that require high resilience and durability.
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Which bronze alloy is best suited for use in seawater or marine environments?
C95400 Aluminum Bronze is highly recommended for marine applications due to its outstanding corrosion resistance in seawater, excellent cavitation resistance, and high strength. It is commonly used for propellers, pump housings, valve seats, and other marine components. C65500 High-Silicon Bronze is also a strong candidate for marine fittings and welded structures due to its excellent corrosion resistance and weldability.
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Why is C65500 High-Silicon Bronze preferred in chemical processing industries?
C65500 High-Silicon Bronze exhibits particularly outstanding corrosion resistance in sulfuric acid and sulfate environments, which are common in chemical processing plants. Beyond its chemical resistance, it also offers high strength, good formability, and excellent weldability — making it a practical and durable choice for heat exchanger tube sheets, pump valves, fasteners, and other chemical processing equipment components.
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How do bronze alloys differ from brass, and when should bronze be chosen over brass?
While brass is a copper-zinc alloy valued for its machinability, aesthetics, and moderate strength, bronze alloys (copper alloyed with tin, aluminum, silicon, or phosphorus) generally offer higher strength, a lower coefficient of friction, and superior chemical and seawater corrosion resistance. Bronze should be preferred over brass when the application demands excellent wear resistance, self-lubricating properties, high load-bearing capacity, or exposure to harsh corrosive environments such as seawater or chemical media.
Finishes and Post-Processing Options
The zinc alloy substrate is highly suitable for various surface treatments to enhance decoration, protection, or functionality:
Electroplating: Such as chrome, nickel, gold, or silver plating, providing a highly decorative appearance, excellent wear and corrosion resistance. This is the most common choice.
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Passivation or Chromate Conversion Coating:
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Powder Coating:
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Painting:
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Physical Vapor Deposition (PVD):
Design and Machining Considerations
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Process Selection:
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Design Considerations:
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Material Selection:
Zamak 3 and 5 are suitable for the vast majority of general-purpose parts requiring good appearance and strength; ZA-8 is better for wear and bearing applications; for making rapid tooling, choose specialized alloys like Kirksite.
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