Bearing Bronzes
This is the copper-tin alloys along with small additions of another constitution. Beneath conditions of heavy load and conditions of severe service, bronzes are mostly of great advantages. Therefore, they possess a high resistance to impact loading and, are mostly employed in locomotive and rolling mills bearings. Though, they get heated up fast as compared to another type of bearing materials, as like: babbitts. Bronze lined bearings are easily eliminated and finished bushings are usually available in stocks. Some of the bronzes that are widely employed are described in Table no.22.
Table no.22: Bearing Bronzes
|
Bronze and
SAE Number
|
Composition (% )
|
Mechanical Properties
|
Application
|
|
UTS N/mm2
|
YS N/mm2
|
Elongation
%
|
|
Leaded gun metal, 63
|
Cu 86-89, Sn 9-11, Pb 1-2.5, P 0.25
max. impurities 0.5 max.
|
200
|
80
|
10
|
Bushing
|
|
Phosphor bronze, 64
|
Cu 78.5-81.5, Sn 9-11, Pb 0.05-0.25, Zn 0.75
max. impurities 0.25 max.
|
167
|
80
|
8
|
Heavy loads
|
|
Bronze backing for lined bearings 66
|
Cu 83-86, Sn 4.5-6.0, Pb 8-10, Zn 2.0, impurities 0.25 max.
|
167
|
80
|
8
|
Bronze backed bearings
|
|
Semi-plastic bronze, 67
|
Cu, 76.5-99.5, Sn 5-7,
Pb 14.5-17.5, Zn 4.0 max., Sb 0.4 max., Fe 0.4 max., impurities 10.0 max.
|
133
|
-
|
10
|
Soft and good antifriction properties
|