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China Bronze CNC Machining Service - Quality Suppliers & Expert Factory for Durable Industrial Components
Common Bronze Alloy Grades and Characteristics
Bronze generally refers to a group of copper‑based alloys, mainly alloyed with tin, aluminum, silicon, manganese, and other elements. Compared with brass (copper‑zinc alloys), bronze typically features higher strength, a lower friction coefficient, and better chemical corrosion resistance—especially in seawater environments. Thanks to its excellent wear resistance and self‑lubricating properties, it plays an irreplaceable role in bearings and bushings. Our machining centers are well‑equipped to process various bronze materials, supporting high‑quality production from complex prototypes to small‑batch manufacturing.
1. C93200 / SAE 660 High-Leaded Tin Bronze · Bearing Bronze
Characteristics: This is the most commonly used bearing bronze grade. Lead is added to form soft particles in the alloy structure, delivering exceptional self-lubrication and anti-galling performance. This makes it particularly suitable for applications with insufficient lubrication, or under high-load and low-speed operating conditions. It features good machinability and reliable wear resistance.
Typical Applications: Suitable for general‑purpose bearings, bushings, thrust washers, pump components, and low‑load gears across various industrial applications.
| 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 |
Values are typical ranges, specific to casting and processing conditions.
2. C95400 Aluminum Bronze
Characteristics: This is a high‑strength, high‑hardness aluminum bronze. It boasts some of the best corrosion resistance, wear resistance, and fatigue strength among all bronze alloys, with performance comparable to many steel materials. It maintains its strength at elevated temperatures and delivers excellent resistance to impact and cavitation.
Typical Applications: Ideal for heavy-duty bearings, gears, valve seats, pump housings, marine propellers and seawater-resistant components, as well as various parts used in chemical processing equipment.
| 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 |
Values are typical ranges, specific to heat treatment condition.
3. C54400 Phosphor Bronze
Characteristics: This is a tin bronze with a small addition of phosphorus. Phosphorus enhances the alloy's elastic limit, fatigue strength, and wear resistance. The material exhibits excellent spring characteristics, good wear and corrosion resistance, and can be readily machined into precision components.
Typical Applications: Perfect for electrical connectors, springs, diaphragms, bellows, wear plates, and high-precision gears across multiple industrial applications.
| 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 |
Values are typical ranges, specific to the degree of cold work.
4. C65500 High-Silicon Bronze
Characteristics: This bronze features exceptional corrosion resistance, especially in sulfuric acid and sulfate environments. It combines high strength, excellent corrosion resistance, good formability and weldability, making it widely applied in the chemical and marine industries.
Typical Applications: Ideal for components in chemical processing equipment, heat exchanger tube sheets, marine hardware and fittings, pump and valve parts, fasteners, as well as welded structural parts.
Frequently Asked Questions
Q
What is the main difference between C93200 bearing bronze and other bronze alloys?
C93200 (SAE 660) is specifically formulated with a high lead content (approximately 7%), which creates soft particles within the alloy matrix. These particles provide outstanding self-lubrication and anti-galling properties, making it the preferred choice for bearings and bushings operating under high-load, low-speed, or poorly lubricated conditions—advantages that most other bronze alloys cannot match.
Q
Why is C95400 Aluminum Bronze often compared to steel?
C95400 offers tensile strength in the range of 620–760 MPa and a Brinell hardness of 170–210, which is comparable to many low-alloy steels. Combined with its excellent corrosion resistance, fatigue strength, and impact resistance, it can serve as a lighter, corrosion-resistant alternative to steel in demanding structural and marine applications.
Q
What role does phosphorus play in C54400 Phosphor Bronze?
Phosphorus serves two key functions in C54400: it acts as a deoxidizer during casting to improve the soundness of the alloy, and it significantly enhances the elastic limit, fatigue strength, and wear resistance of the material. This makes Phosphor Bronze especially well-suited for spring contacts, precision gears, and other components requiring high resilience and long fatigue life.
Q
In which environments does C65500 High-Silicon Bronze perform best?
C65500 excels in highly corrosive environments, particularly where exposure to sulfuric acid, sulfates, or seawater is a concern. Its silicon content provides a protective oxide layer that resists chemical attack. Additionally, its excellent weldability makes it a practical choice for fabricated assemblies in chemical processing plants and marine infrastructure.
Q
How do I choose the right bronze alloy for my machined components?
The selection depends on your application's primary requirements: choose C93200 for general bearings and bushing applications requiring self-lubrication; select C95400 when high strength, hardness, and seawater resistance are critical; opt for C54400 when spring-like elasticity, precision, and fatigue resistance are needed; and use C65500 when superior corrosion resistance and weldability are the priority. Our engineering team can help evaluate your specific load, environment, and tolerance requirements.
Q
Can bronze alloys be used for both prototype and small-batch production?
Yes. Our CNC machining centers are fully equipped to handle bronze alloys across all grades, from single complex prototypes to small and medium production runs. Bronze materials generally offer good machinability, and our capabilities ensure tight tolerances, excellent surface finishes, and consistent quality whether you need one part or several hundred.
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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