Bearing Bronze Materials Compared: 5 Common Alloys for Bronze Bushings and Plain Bearings

Five widely used bearing bronzes — SAE 660, C92500, C95500, C86300 and C90800 — compared by composition, strength and hardness, with practical selection guidance for bronze bushings and plain bearings.

When a bronze bushing or plain bearing fails early, the cause is often not machining or lubrication — it is the alloy. Copper-based bearing materials vary widely in strength, wear behaviour and corrosion resistance, and selecting the right grade is largely a matter of matching the alloy to the duty: load, speed, environment and lubrication.

This article compares five commonly specified bearing bronzes across three casting routes (sand, centrifugal and continuous casting) and explains where each one performs well. Property values are typical minimums and can vary with casting process and section size.

The five alloys at a glance

Alloy by alloy

01 · General purposeSAE 660 (C93200 / CC493K) — the classic all-rounder

With 5–8% lead, SAE 660 is the classic all-rounder among bearing bronzes. Lead particles act as a built-in solid lubricant and chip breaker, giving the alloy good embeddability and conformability — it tolerates slight misalignment, dirt particles and occasional marginal lubrication better than lead-free grades. Strength is moderate but sufficient for most general machinery, and it is the most economical of the five.

Suited to: pumps, machine tools, agricultural and textile machinery; medium loads, moderate speeds, reliably lubricated service.

02 · Heavier dutyC92500 (CC482K) — higher-tin leaded bronze

Tin content of 10–12.5% with lead reduced to 2% or less gives C92500 higher hardness and better fatigue resistance than SAE 660 while retaining a degree of lead for running-in.

Suited to: low-speed, heavy or shock-loaded bearings, particularly where the shaft is harder than the bushing and the bearing is expected to take most of the wear.

03 · Corrosive serviceC95500 (CC333G) — nickel aluminium bronze

The aluminium-iron-nickel combination produces 600–650 MPa tensile strength, strong resistance to seawater and salt-spray corrosion, and good strength retention at elevated temperature. Note that lead content is very low, so anti-seizure performance in dry or poorly lubricated contact is limited; reliable lubrication is required, or graphite plugs can be added for self-lubricating versions.

Suited to: marine shafting, hydraulic cylinders, mining crushers, seawater pumps — heavy loads in corrosive environments.

04 · Extreme loadC86300 (CC762S) — high-strength manganese bronze

C86300 delivers the highest tensile strength (750 MPa) and hardness (190 HB) of the five grades, with strong resistance to abrasive wear and impact, at a favourable cost. It is lead-free, however, so friction is higher and the mating shaft should be hardened with forced lubrication.

Suited to: rolling-mill nuts, heavy excavator and crane slewing rings, jack nuts and heavy sliding components under extreme load and low speed.

05 · Wear & fatigueC90800 (CC483K) — high-tin bronze

With 11–13% tin, C90800 is prized for wear resistance, fatigue resistance and corrosion resistance, and is a common choice in precision and aerospace-related bearing applications.

Suited to: pump shaft bearings, turbines, food-processing machinery bushings; higher speeds, frequent start-stop cycles and fluctuating lubrication.

Selection guide: match the grade to the duty

Practical notes

• Hardness pairing: the shaft should be harder than the bushing. The harder bearing alloys (C86300, C95500) require correspondingly harder shaft surfaces.
• Lubrication: leaded grades tolerate marginal lubrication; lead-free high-strength grades require dependable lubrication.
• Self-lubricating option: where oil supply is intermittent, any of these alloys can be specified with graphite plugs for maintenance-free running.