Thrust washer data

PTFE composite thrust washers
DimensionsNot standardized

Tolerances
Table 1

Materials
For additional information (Design and variants)

Steel backing with a layer of sintered tin/bronze, pores filled and covered with a running-in layer of PTFE with molybdenum disulphide additives

Permissible operating temperature range-200 to +250 °C (-330 to +480 °F)

Permissible load
Dynamic: 80 N/mm2
Static: 250 N/mm2

Permissible sliding velocity2,0 m/s (6.5 ft/s)

Coefficient of friction µ
0,03 to 0,25

Chemical properties
Steel backing and sintered tin/bronze layer are the primary factors in determining the chemical resistance of SKF composite plain bearings, as the sliding (covering) layers are resistant to most chemicals. The covering layer is virtually inert because of its PTFE content, although at increasing temperatures molten alkali metals and free fluorine attack it.
At room temperature the sintered tin/bronze structure has good resistance to sea water, steam, atmospheric influences, salt solutions and sulphuric acid, but not to oxidizing acids or media containing ammonia.
All exposed surfaces of the steel backing are electrolytically tin-plated but this provides only limited protection against corrosion in most applications. In cases where the washers are to be exposed to corrosive media, or where there is a risk of corrosion in the contact between the steel backing and the housing material, the backing can be protected by a nickel, chromium or zinc coating applied electrolytically.
For additional information, contact the SKF application engineering service.



POM composite thrust washers
Dimensions
Not standardized

Tolerances
Table 1

Materials
For additional information (Design and variants)

Steel backing with a layer of sintered tin/bronze, pores filled and covered with a layer of POM composite

Permissible operating temperature range-40 to +110 °C (-40 to +230 °F), +130 °C (+265 °F) for short periods

Permissible load
Dynamic: 120 N/mm2
Static: 250 N/mm2

Permissible sliding velocity2,5 m/s (8.2 ft/s)

Coefficient of friction µ
0,02 to 0,20

Chemical properties
Steel backing and sintered tin/bronze layer are the primary factors in determining the chemical resistance of SKF composite plain bearings, as the sliding (covering) layers are resistant to most chemicals. The acetal resin-covering layer is largely resistant to organic substances.
At room temperature the sintered tin/bronze structure has good resistance to sea water, steam, atmospheric influences, salt solutions and sulphuric acid, but not to oxidizing acids or media containing ammonia.
All exposed surfaces of the steel backing are electrolytically tin-plated but this provides only limited protection against corrosion in most applications. In cases where the washers are to be exposed to corrosive media, or where there is a risk of corrosion in the contact between the steel backing and the housing material, the backing can be protected by a nickel, chromium or zinc coating applied electrolytically.
For additional information, contact the SKF application engineering service.

Electrical propertiesThe acetal resin-covering layer may act as electrical insulators when new. To avoid the build-up of static electricity, components at risk should be grounded.
For additional information, contact the SKF application engineering service.



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