Calculation of PV Values: PV = P x V (N/mm² x m/s)

The PV value is the sum of the products of a bearing’s load and linear velocity under specified conditions. It is inversely proportional to the bearing’s service life; thus, it is recommended to use a lower, safer PV value during design to ensure a longer lifespan for the bearing. While the PV values for different materials are specified in the sample, these measurements are taken under conditions of radial rotation. In practice, designers must consider a multitude of factors when designing for bearing life.

Additionally, ambient temperature is a crucial factor that must be taken into account. A rise in temperature can alter the fit clearance between the bearing and the seat hole, as well as the fit tolerance between the shaft and the bearing bore, thereby impacting the bearing’s normal operation.

Factors Influencing Bearing Service Life:

• Bearing load and mode of load application
• Linear velocity
• PV value
• Surface roughness of the mating parts
• Heat treatment methods of the mating parts
• Environmental temperature

The wear and service life of  slide bearings depend on several factors, including:

• Specific bearing load
• Sliding speed
• PV value
• Roughness depth of the mating surface
• Material of the mating surface and temperature conditions

Bronze Bearing Alloys – Engineering Data Overview

Structured reference including mechanical performance and typical operating guidance for bearing design.

*PV values are typical dry or boundary-lubricated reference ranges. Actual limits depend on lubrication, surface finish, temperature, and shaft hardness.

Design Notes (Engineering Perspective)

1. Leaded Tin Bronzes (C93200 / C93700)

• Excellent embeddability and conformability

• Ideal for contaminated environments

• Lower strength → not suitable for shock or very high surface pressure

2. Tin & Phosphor Bronzes (C90300 / C52100)

• Higher fatigue resistance

• Better for dynamic or oscillating motion

• Common in wrapped bearing structures

3. Aluminum Bronzes (C95400 / C95500)

• High compressive strength

• Superior wear resistance

• Strong seawater corrosion resistance

• Preferred in port equipment, offshore, mining machinery

4. Manganese Bronze (C86300)

• Highest strength in this group

• Often graphite-plugged for maintenance-free service

• Used where load capacity is the dominant design factor

Complete Guide to Bronze Bearing Materials & Alloys

Meta Description: Discover the technical properties of bronze bearing alloys, including SAE 660 (C93200), Aluminum Bronze, and Phosphor Bronze. Learn about load capacity, wear resistance, and VIIPLUS manufacturing configurations.

1. Material Overview: What Is Bronze?

Bronze is the definitive material in plain bearing technology. Technically defined as a copper alloy where tin is the primary strengthening addition, bronze is engineered to offer a balance of hardness, ductility, and thermal management.

By introducing tin and other elements to the copper matrix, manufacturers create alloys that increase hardness and mechanical strength while preserving copper’s natural thermal conductivity and corrosion resistance.

VIIPLUS Bronze Manufacturing Configurations

At VIIPLUS, we engineer bronze bearings to meet precise tribological needs. Our manufacturing capabilities include:

• Solid Cast Bushings: For heavy-duty structural support.

• Precision-Machined Flanged Bearings: For axial and radial load handling.

• Thin-Wall Wrapped Bronze Sleeves: For compact, space-saving designs (e.g., CuSn8).

• Graphite-Plugged Bushings: For self-lubricating, maintenance-free operations (Oilless).

2. Why Bronze Performs So Well in Bearings

Bronze remains the industry standard for sliding bearings due to four distinct tribological advantages:

• Superior Wear Resistance: The interaction between Tin (Sn) and Copper (Cu) forms hard intermetallic phases. These phases resist surface abrasion and fatigue, extending service life.

• High Load Capacity: Depending on the specific alloy grade, bronze bearings can tolerate static surface pressures exceeding 100 N/mm².

• Efficient Heat Dissipation: The copper matrix acts as a thermal conductor, efficiently transferring frictional heat away from the shaft and sliding interface to prevent overheating.

• Anti-Galling & Seizure Resistance: When running against steel shafts, bronze exhibits anti-galling behavior, reducing adhesive wear and preventing seizure even under boundary lubrication conditions.

3. The Industry Benchmark: C93200 (SAE 660)

Leaded Tin Bronze, also known as SAE 660, is the most widely used copper alloy for bushings and bearings. It offers an excellent balance of strength, wear resistance, and anti-friction properties.

Technical Data: C93200 (Bearing Bronze)

4. Bronze Families: Alloy Selection Guide

Material selection must balance load intensity, sliding speed, lubrication type, and environmental exposure. Below is a breakdown of the primary bronze families used in bearing applications.

A. Tin Bronze (Cu + 5–12% Sn)

• Key Features: The traditional choice for bearings. Contains hard δ-phase particles for wear resistance and offers good corrosion resistance.

• Best For: Moderate loads and speeds.

• Representative Grades: C90300, C90500, C90700.

• Applications: Industrial bushings, pump valves, marine hardware.

B. Leaded Tin Bronze (Cu + Sn + 5–25% Pb)

• Key Features: Lead inclusions create “internal lubrication,” offering excellent machinability and strong resistance to seizure (anti-friction).

• Best For: General-purpose industrial machinery.

• Representative Grades: C93200 (SAE 660), C93700, C93800.

• Applications: Earth-moving equipment, hydraulic cylinder bushings, construction machinery.

C. Phosphor Bronze (Cu + 5–10% Sn + ~0.2% P)

• Key Features: A dense, refined microstructure with improved fatigue resistance and elasticity. Ideally suited for thin-wall formats.

• Best For: High-fatigue environments and wrapped bearings.

• Representative Grades: C51000 (CuSn5), C52100 (CuSn8), C54400.

• Applications: Wrapped bronze bushings (VIIPLUS 090), electrical connectors, precision springs.

D. Aluminum Bronze (Cu + 9–14% Al + Fe/Ni)

• Key Features: Exceptionally high strength and hardness. Forms a protective aluminum oxide surface layer that provides superior seawater corrosion resistance. Non-sparking.

• Best For: Corrosive marine environments and heavy loads.

• Representative Grades: C95400, C95500, C95800.

• Applications: Offshore oil & gas components, marine propulsion bearings, heavy-duty pivots.

E. Manganese Bronze (Cu + Zn + Al + Mn + Fe)

• Key Features: Delivers very high mechanical tensile strength and impact resistance.

• Best For: High load / Low speed (High-torque) operations. Often used with solid lubricant plugs.

• Representative Grades: C86300, C86400, C86500.

• Applications: Graphite-plugged oilless bearings, mold and die components, heavy plant machinery.

F. Silicon Bronze (Cu + 3–4% Si + Mn)

• Key Features: Combines strength with excellent weldability and corrosion resistance.

• Best For: Assemblies requiring welding or repair.

• Representative Grades: C65500, C65100.

• Applications: Chemical processing hardware, structural weldable assemblies.

FAQ: Choosing the Right Bronze Bearing

Q: Which bronze is best for high speeds?
A: Leaded Tin Bronze (SAE 660) is generally best for higher speeds due to the lubricating properties of lead, provided there is adequate external lubrication.

Q: Which bronze is best for heavy loads?
A: Aluminum Bronze and Manganese Bronze offer the highest compressive strength for heavy static and dynamic loads.

Q: What is the difference between Tin Bronze and Phosphor Bronze?
A: Phosphor bronze contains phosphorus, which acts as a deoxidizer, increasing the hardness, fatigue strength, and wear resistance compared to standard tin bronze. It is widely used for thin-walled wrapped bearings (CuSn8).