Sliding material and bushing type selection guides

The following overviews provide comparisons that can be used as a preselection between the different sliding materials and bushing types.
Table 1 compares the operating characteristics of the different bearing types and sliding materials.

In the following sections, all bushing types are compared against each other based on their main technical data. For detailed information and values, refer to the relevant bearing data sections under Bushing data, Thrust washer data, or Strip data.
For additional information, contact the SKF application engineering service.

Ambient temperature range

Diagram 1 compares the permissible ambient temperature ranges of the different bushing types and sliding materials under normal operating conditions. The temperature ranges for SKF solid and wrapped bronze bushings can be extended by using special lubricants. 

Coefficient of friction

The primary factors that affect the friction of SKF sliding materials against their mating surfaces include load, sliding velocity, surface roughness of the mating surface and lubrication conditions. Lower coefficients of friction are obtained under heavy specific loads at low sliding velocities, except for SKF sintered bronze. Both higher and lower friction can occur under extreme conditions.

Diagram 2 compares the coefficient of friction under dry or initially lubricated operating conditions of different SKF sliding materials. 

Load capacity

The load carrying capacity of a specific bushing depends on several factors including the type of load, sliding velocity and frequency of oscillation. Diagram 3 compares the permissible specific bearing load of different SKF sliding materials under dynamic and static conditions.

Siding velocity

All sliding materials supplied by SKF can operate under rotational, oscillating and linear movements. The permissible sliding velocity for a specific application also depends on load, shaft surface and heat dissipation. Diagram 4 compares the permissible continuous sliding velocity of different SKF sliding materials.

Shaft recommendations

Larger tolerance classes can be applied when the application demands are moderate.
The surface roughness often has a significant influence on service life. However, a surface roughness with a value greater than 0,4 mm may have a negative effect.
The heavier the load, the harder the shaft should be. The higher the risk for embedded contaminants, the more a harder shaft is required.
Diagram 5 compares the SKF shaft recommendations for ISO tolerance classes, surface roughness and hardness of different SKF sliding materials.
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