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Cast tin bronzes and leaded tin bronzes

Dr. Dmitri Kopeliovich

According to the Unified Numbering System (UNS):

Tin Bronzes are copper alloys, containing 7-19% of tin (Sn) as the major alloying element. Cast Tin Bronzes (Tin Bronze, Gun Metal, Tin Bronze 65, Nickel Gear Bronze) are designated with the numbers from C90000 through C91999.

Leaded Tin Bronzes are copper alloys, containing 5-16% of tin (Sn) and up to 30% of lead (Pb) as the major alloying elements and up to 4% of zinc (Zn) and up to 1.6% of nickel (Ni) as additional alloying elements. Cast Leaded Tin Bronzes (Naval M Bronze, Leaded Tin Bronze, Bearing Bronze, Anti-Acid Metal, Soft Bronze) are designated with the numbers from C92000 through C94500 (including High Leaded Bronzes).

Tin Bronzes containing up to 13% of tin have mono-phase structure (α-phase).

Such alloys possess relatively high ductility.

Alloys, containing more than 13% of tin, have significant amount of brittle δ-phase.

Ductility of these Tin Bronzes is very low.

Lead is added to the alloys (Leaded Tin Bronzes) for improvement their machinability and increasing pressure tightness. Mechanical strength and ductility of the Leaded Tin Bronzes is lower than those of Tin Bronzes.

Cast High Leaded Tin Bronzes (C93000 – C94500) contain more lead (10-30%), than Leaded Tin Bronzes. Cast High Leaded Tin Bronzes are used as sliding bearing materials. High content of lead, dispersed as separate phase throughout copper-tin matrix, imparts anti-friction properties to the alloy.

Cast Tin Bronzes and Leaded Tin Bronzes are used for manufacturing sleeve bushings,pump impellers, piston rings, electrical connectors, valve bodies, water conditioners, gears, engine bearings, pump bodies, pump parts for acid mine water, railroad parts.

Chemical compositions of some сast tin bronzes and leaded tin bronzes

UNS Designation Trade mark Sn,% Pb,% P,% Zn,% Ni,% Cu,%
C90300 Tin Bronze 7.5-9.0 0.30 max. 0.05 max. 3.0-5.0 1.0 max. 86-89
C90500 Gun Metal 9.0-11.0 0.30 max. 0.05 max. 1.0-3.0 1.0 max. 86-89
C90700 Tin Bronze, 65 10.0-12.0 0.50 max. 0.05 max. 0.50 max. 0.50 max. 88-90
C91700 Nickel Gear Bronze 11.3-12.5 0.25 max. 0.30 max. 0.25 max. 1.2-2.0 88-90
C92200 Naval M Bronze 5.5-6.5 1.0-2.0 0.05 max. 3.0-5.0 1.0 max. 86-90
C92700 Leaded Tin Bronze 9.0-11.0 1.0-2.5 0.25 max. 0.70 max. 1.0 max. 86-89
C93700 Bearing Bronze 9.0-11.0 8.0-11.0 0.10 max. 0.80 max. 0.50 max. 78-82
C93800 Anti-Acid Metal 4.5-6.0 23.0-27.0 0.10 max. 0.80 max. 0.50 max. 78-82
C94300 Soft Bronze 9.0-11.0 8.0-11.0 0.08 max. 0.80 max. 1.0 max. 78-82

Properties of some cast tin bronzes and leaded tin bronzes

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cast_tin_bronzes_and_leaded_tin_bronzes.txt · Last modified: 2013/04/06 by dmitri_kopeliovich
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