Why is phosphor bronze used for bushes?

It wears slowly, runs smoothly against steel shafts, carries good loads and resists corrosion.

What is the difference between PB1 and PB2?

PB2 has a little more tin (about 11–12% against 10%), making it harder for heavier loads such as worm wheels.

Is phosphor bronze the same as brass?

No. Bronze is copper with tin; brass is copper with zinc. Phosphor bronze wears better as a bearing; free-cutting brass machines faster.

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Phosphor bronze

Also called: PB1, PB2, CuSn10P, tin bronze, phosphor bronze bush, bronze casting

Phosphor bronze is a copper-tin alloy with a little phosphorus. It wears slowly, runs smoothly against steel and resists corrosion, so cast grades such as PB1 and PB2 are the classic material for bushes, bearings, worm wheels and pump parts.

Quick facts

Type: Copper-tin (tin bronze) alloy
Tin: About 10–12% in cast PB1 / PB2
Phosphorus: About 0.5–1%
Typical hardness: About 70–100 HB (cast)
Strengths: Wear resistance, low friction against steel, corrosion resistance
Forms: Cast bars and tubes (continuous or centrifugal), castings

Common grades

Grade	Notes
PB1 (BS 1400)	About 10% tin; general bearings and bushes; close to CuSn10P
PB2 (BS 1400)	About 11–12% tin; heavier loads, worm wheels
Wrought phosphor bronze (e.g. CuSn5, CuSn8)	Strip and wire for springs and electrical contacts

Typical uses

Plain bearings and bushes
Worm wheels and gears
Pump impellers and valve parts
Thrust washers and wear plates
Marine fittings

Phosphor bronze or other bearing materials?

Leaded bronze (LTB): better when lubrication is poor
Aluminium bronze: higher strength for heavy loads
Gun metal (LG2): general pump and valve castings
Sintered or plastic bushes: low cost for light duty

Need parts made in Phosphor bronze?

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Related job work

Machines

CNC lathe

Materials

Free-cutting brass (CuZn39Pb3)

Questions

Why is phosphor bronze used for bushes?: It wears slowly, runs smoothly against steel shafts, carries good loads and resists corrosion.
What is the difference between PB1 and PB2?: PB2 has a little more tin (about 11–12% against 10%), making it harder for heavier loads such as worm wheels.
Is phosphor bronze the same as brass?: No. Bronze is copper with tin; brass is copper with zinc. Phosphor bronze wears better as a bearing; free-cutting brass machines faster.

The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 8 October 2026.