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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
What is the difference between bronze and brass?
Bronze is primarily a copper-based alloy using tin, aluminum, silicon, or manganese as the main alloying elements, while brass is a copper-zinc alloy. Compared to brass, bronze generally offers higher strength, a lower friction coefficient, and superior corrosion resistance—particularly in seawater and chemical environments.
Which bronze grade is best for bearing and bushing applications?
C93200 / SAE 660 (High-Leaded Tin Bronze) is the most widely used grade for bearings and bushings. Its high lead content creates soft particles within the alloy structure, providing exceptional self-lubrication and anti-galling performance—especially effective under high-load, low-speed, or insufficient lubrication conditions.
Which bronze alloy offers the highest strength and hardness?
C95400 (Aluminum Bronze) offers the highest strength and hardness among common bronze grades, with a tensile strength of 620–760 MPa and Brinell hardness of 170–210. Its performance is comparable to low-alloy steels, making it suitable for heavy-duty bearings, gears, marine propellers, and structural components.
What makes Phosphor Bronze (C54400) suitable for spring and electrical connector applications?
The addition of phosphorus in C54400 significantly enhances the alloy's elastic limit, fatigue strength, and wear resistance. This gives the material excellent spring characteristics and dimensional stability under cyclic loading, making it ideal for electrical connectors, springs, diaphragms, bellows, and precision gears.
Which bronze grade is most resistant to chemical and seawater corrosion?
C65500 (High-Silicon Bronze) offers exceptional corrosion resistance, particularly in sulfuric acid and sulfate environments. C95400 (Aluminum Bronze) is also highly resistant to seawater corrosion and is commonly used for marine propellers and seawater-exposed components. The best choice depends on the specific chemical environment of the application.
Can these bronze alloys be used for both prototypes and small-batch production?
Yes. Our machining centers are fully equipped to process all of the bronze grades listed above—C93200, C95400, C54400, and C65500. We support high-quality production across the full range, from complex one-off prototypes to small and medium batch manufacturing, ensuring consistent dimensional accuracy and surface finish.
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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