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China Bronze CNC Machining Services by Top Suppliers and Factory for High-Quality 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)
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.
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)
High-Strength Grade
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.
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)
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.
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)
Superior Corrosion Resistance
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.
Typical Applications: Chemical processing equipment components, heat exchanger tube sheets, marine fittings, pump valves, fasteners, welded structures.
Frequently Asked Questions
Q
What is the difference between bronze and brass?
Brass is a copper-zinc alloy, while bronze is primarily copper alloyed with tin, aluminum, silicon, or other elements. Bronze generally offers higher strength, a lower coefficient of friction, and better corrosion resistance — especially in seawater — compared to brass.
Q
Which bronze alloy is best for bearing and bushing applications?
C93200 (SAE 660 / High-Leaded Tin Bronze) is the most widely used alloy for bearings and bushings. Its high lead content creates soft particles within the matrix that provide excellent self-lubricating and anti-galling properties, making it ideal for high-load, low-speed, or poorly lubricated conditions.
Q
Why is C95400 Aluminum Bronze compared to steel?
C95400 achieves tensile strengths of 620–760 MPa in heat-treated condition, which is comparable to many low-alloy steels. Combined with its excellent corrosion resistance, cavitation resistance, and ability to retain strength at elevated temperatures, it is a strong candidate for heavy-duty structural and marine applications where steel would corrode.
Q
What role does phosphorus play in C54400 Phosphor Bronze?
Phosphorus serves two key functions: it acts as a deoxidizer during casting to improve alloy quality, and it raises the elastic limit, fatigue strength, and wear resistance of the finished material. This makes C54400 particularly well-suited for springs, electrical connectors, and precision components that undergo repeated flexing.
Q
In what environments does C65500 High-Silicon Bronze perform best?
C65500 excels in chemically aggressive environments, especially those involving sulfuric acid and sulfate solutions. Its combination of high corrosion resistance, good weldability, and solid mechanical strength also makes it a reliable choice for marine fittings, heat exchanger components, and welded structural assemblies.
Q
How do I choose the right bronze alloy grade for my application?
The selection depends on your primary requirements. For self-lubricating bearings under moderate loads, C93200 is the standard choice. For maximum strength and wear resistance in heavy-duty or seawater environments, C95400 is preferred. If your application demands spring-like elasticity or precision electrical contacts, C54400 Phosphor Bronze is ideal. For chemical processing or marine welded structures requiring top corrosion resistance, C65500 is the go-to option.
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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