silicon brass sleeve bearing with graphite plugs, used in a high-strength valve assembly for a water treatment plant.
cast silicon brass bushing with graphite plugs, designed for a marine valve that requires corrosion resistance and self-lubrication.

Silicon Brass: The High-Strength Choice for Oil-Free Bearings

In demanding industrial, marine, and hydraulic applications, bearings require more than just basic functionality—they demand superior strength and resistance to harsh conditions. Silicon brass alloys, with their high silicon content, provide this critical edge. As a premier manufacturer of oil-free bearings, we specialize in leveraging the unique properties of silicon brass to create high-performance components that excel where other materials fail. These alloys deliver exceptional wear resistance and strength, making them the ideal choice for environments with high loads, high speeds, or corrosive elements.

A Technical Deep Dive into Our Silicon Brass Alloys

Silicon brass alloys are a family of copper-based materials where silicon is the primary strengthening agent. This element forms a solid solution with copper, significantly increasing the alloy’s tensile strength and hardness. This makes silicon brass a robust alternative to traditional bronze, particularly in applications where high compressive loads and excellent corrosion resistance are required.

The table below provides a detailed look at the chemical composition of our core silicon brass alloys, all manufactured to strict ASTM standards.

Chemical Composition of Silicon Brass Alloys

CDA Number Cu (%) Zn (%) Si (%) Pb (%) Mn (%) Fe (%) Other (%)
C87300 94.0 Min. < 0.25 3.5 – 4.5 < 0.05 0.8 – 1.5 < 0.2 Al < 0.10
C87500 79.0 Min. 12.0 – 16.0 3.0 – 5.0 < 0.05 – – Al < 0.10
C87600 88.0 Min. 4.0 – 7.0 3.5 – 5.5 < 0.05 0.25 < 0.2 –
C87610 90.0 Min. 3.0 – 5.0 3.0 – 5.0 0.09 < 0.25 < 0.2 –
C87800 80.0 Min. 12.0 – 16.0 3.8 – 4.2 < 0.05 < 0.15 < 0.15 Sn < 0.25, Sb < 0.5
C87850 75.0 – 78.0 Remainder 2.7 – 3.4 < 0.09 – – P 0.05 – 0.20

Contrasting Logic: Silicon Brass vs. Leaded Bronze

While both silicon brass and leaded bronze are excellent choices for specific bearing applications, their core strengths differ significantly.

Feature Silicon Brass (C87xxx) Leaded Bronze (C8xxx, C9xxx)
Primary Strengthening Agent Silicon (Si) Tin (Sn)
Self-Lubrication Relies heavily on graphite plugs/grooves or an external source due to high hardness. Relies on the soft lead phase for inherent self-lubricating properties.
Strength & Hardness Superior. Silicon significantly increases tensile strength and hardness. High. Tin provides strength, but generally has a softer matrix due to lead content.
Corrosion Resistance Excellent. High resistance to seawater and corrosive industrial environments. Good. Effective in many environments but can be less resistant to specific chemical attack.

Silicon Brass in Action: Applications for Oil-Free Bearings

Our silicon brass alloys are engineered to perform flawlessly in a variety of critical bearing applications, particularly where strength and environmental resistance are key.

1. Heavy-Duty & Marine Bearings

Alloys like C87500 and C87800 are a top choice for severe-duty applications. Their robust composition is perfect for:

  • Specific Locations: Marine propeller shafts and seawater pump bearings, where they resist corrosion while handling heavy loads.
  • Machinery: They are widely used for bushings in construction vehicles and other high-load industrial machinery.

2. High-Speed & High-Performance Bearings

The combination of strength and wear resistance in our alloys makes them suitable for high-speed components.

  • Specific Locations: C87300 is ideal for high-speed motor bearings, while C87610 excels in pump shaft bearings and turbocharger components.

3. Bearings for Corrosive Environments

C87600 and C87850 are specifically formulated for their outstanding corrosion resistance.

  • Specific Locations: These alloys are the go-to solution for bearings in seawater pumps, marine rudder bearings, and chemical processing equipment.

Graphite Plugs and Grooves in Oil-Free Bearings: Silicon Brass Alloys

  1. Solid bronze bearings (e.g., C87300, C87600) are plain bearings/bushings suited for high-load, high-temperature applications like hydraulic pumps, marine equipment, and machinery in abrasive environments.

  2. Graphite-embedded bearings (e.g., C87610, C87800) are graphite-impregnated for enhanced self-lubrication, ideal for turbine bearings, high-speed machinery, and pumps.

  3. Split bearings with grooves (e.g., C87850) feature grooves to retain lubrication and minimize friction, making them suitable for high-load, severe-duty applications in construction or industrial machinery.
Integrating graphite plugs or grooves into silicon brass bearings optimizes performance by creating a self-lubricating system. This combination is crucial for bearings in hydraulic pumps, gearbox bushings, and compressors facing high-load, dry-running conditions, as the graphite continuously lubricates, reducing friction and extending service life.

Summary of Silicon Brass Alloys for Oil-Free Bearings:

CDA Number Composition Application Area Specific Use
C87300 94.0% Cu Min., 3.5-4.5% Si, 0.8-1.5% Mn Industrial bearings Pumps, high-load bushings, high-speed motors
C87500 79.0% Cu Min., 12.0-16.0% Zn, 3.0-5.0% Si Marine shaft bearings Marine propeller shafts, seawater pumps
C87600 88.0% Cu Min., 4.0-7.0% Zn, 3.5-5.5% Si Industrial bearings Hydraulic pumps, gearbox bushings
C87610 90.0% Cu Min., 3.0-5.0% Zn, 3.0-5.0% Si High-performance bearings Turbochargers, high-speed machinery
C87800 80.0% Cu Min., 12.0-16.0% Zn, 3.8-4.2% Si Heavy-duty bearings Marine shaft bearings, compressors
C87850 75.0-78.0% Cu, 2.7-3.4% Si, 0.05% Pb Corrosion-resistant bearings Marine systems, high-temperature machinery

By adding graphite plugs or grooves, these alloys can function more effectively in dry running conditions or areas where lubrication is limited. The combination of Silicon Brass alloys with graphite-enhanced designs makes them highly suitable for high-wear and high-performance applications.

Conclusion: Your Partner in High-Strength Bearing Solutions

Our portfolio of silicon brass alloys—including C87300, C87500, C87800, and others—provides a superior choice for oil-free bearings in high-load, high-speed, and corrosive environments. By leveraging the exceptional strength and corrosion resistance of these materials, we deliver reliable, long-lasting solutions that keep your machinery running efficiently and without the need for traditional lubrication.

Ready to enhance your equipment’s performance and durability? Contact us today to find out how our silicon brass bearing solutions can meet the unique challenges of your application.

At Bearingface.com, we are more than suppliers; we are technical partners dedicated to solving your toughest friction and wear challenges. By choosing us, you are investing in quality, expertise, and a commitment to performance. Stop compensating for inadequate bearings. It’s time to engineer failure out of your system.

Oil-free bearing alloys produced. We help you specify the correct self-lubricating bronze parts and components for your machinery.