Reference guide

Continuous cast

The lead content in high-leaded tin bronze alloys is between 7 percent and 30 percent. This group of alloys is free cutting and retains favorable thermal conductivity and good lubricity due to the presence of lead. High-leaded tin bronzes are ideal for bearing applications where there could be a loss of the lubrication boundary. These alloys perform extremely well in unforgiving environments where foreign matter may be present, such as dirt and other foreign materials. They are able to envelope foreign matter due to their malleable nature and, in doing so, protect the wear surface of a coupled part.


Product description: High-leaded tin bronze
Solids: 1/2" to 10" O.D.
Tubes: 1" to 16" O.D.*
Rectangles: Up to 10"
Standard lengths: 144"
Shape/Form: Semi-finished, mill stock or near-net shapes, anode, bar stock, billet/bloom, squares, hex, plate, profile or structural shape, flats/rectangular bar

 *Consult mill for wall thickness

Typical uses

Industrial: High-speed bearings for light loads, high-speed/light-to-medium pressure bushings, railroad applications, soft bushings, soft metal applications

Similar or equivalent specification

CDA ASTM SAE AMS Federal Military Other
C94300 B505
  QQ-C-390, E1; QQ-B-1005, Comp 18 MIL-B-16261, Grade V Soft Bronze

Chemical composition

Cu% Pb% Sn% Zn% Fe% P% Ni%1 Al% S%2 Sb% Si%
Chemical composition according to ASTM B505/B505M-23

1Ni value includes Co.   2For continuous castings, S shall be 0.25% max.
Note: Cu + sum of named elements, 99.0% min. Single values represent maximums.


Copper alloy UNS No. Machinability rating Density (lb/in3 at 68 °F)
C94300 80 0.336

Mechanical properties

Mechanical properties according to ASTM B505/B505M-23
Tensile strength, min Yield strength, at 0.5% extension under load, min Elongation, in 2 in. or 50 mm min Brinell hardness (500 kg load) Remarks
ksi MPa ksi MPa % typical BHN  
21 145 15 103 7 45  

Physical properties

Physical properties provided by CDA
  US Customary Metric
Density 0.336 lb/in3 at 68 °F 9.3 gm/cm3 at 20 °C
Specific gravity 9.3 9.3
Electrical conductivity 9% IACS at 68 °F 0.053 MegaSiemens/cm at 20 °C
Thermal conductivity 36.2 Btu · ft/(hr · ft2 · °F) at 68 °F 62.7 W/m at 20 °C
Specific heat capacity 0.09 Btu/lb/°F at 68 °F 377.1 J/kg at 20 °C
Modulus of elasticity in tension 10500 ksi 72400 MPa
Incipient Melting 600 °F 316 °C
Magnetic Permeability 1 1

Fabrication properties

Fabrication properties provided by CDA
*Since brazing is performed within the hot-short range, strain must be avoided during brazing and cooling.
Technique Suitability
Soldering Good
Brazing* Poor
Oxyacetylene welding Not recommended
Gas shielded arc welding Not recommended
Coated metal arc welding Not recommended
Machinability rating 80

Thermal properties

Thermal properties provided by CDA
*Temperature is measured in fahrenheit.   **For stress relief, solution treatment and annealing - time is measured in hours/inch of thickness. For precipitation heat treatment - time is measured in hours.
Treatment Value* Time**
Stress relief 500  
Solution treatment   0

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