SF-2 Marginal-Lubrication Bearing Bushing



Characteristic of performance:

    SF-2 is triple-layer self lubricating material that can fill modified POM plastic as surface layer; it is benignant boundary lubrication material, therefore, it is particularly applicable highload low-speed rotating and wing movement, as well as in the condition that frequent loaded start-stop is the requirement while hydrodynamic lubrication membrane is difficult to form, in the parts such as bearing, thrust washer, sliding block, ball socket and so on. SF-2 can take full advantage of less grease to work long time without lubrication maintenance under boundary lubrication condition. But under oil-free condition, SF-2 the frictional behavior and permissible PV value ls relatively low, so generally storage pit can be formed on the plastic surface, where lithiumbased lubricant grease or silicone grease and so on should be applied when being installed.

Wear Rules:

   SF-2 material follows special wearing rule as shown in Fig.4, infinitesimal abrasion can occur in R phase when being applied with grease and then being installed. But after the R phase, the boundary lubrication condition will disappear and wearing will be exaggerated. If you do refill with oil, the product can be drastically held by non-remarkable wearing and its life will also be greatly extended.

Therefore the advantage of SF-2 material is that oil shall be added with an interval of R, which is remarkably longer that of R other metal materials. It is approximately five times as long.

     When SF-2 bush is installed with application of grease such as lithium-based or silicone grease, its service life varies from the PV value under working condition, for instance, when PV value is about 2.5MPam/s, its service life will be about 200hr; when PV value is 0.1Mpa-m/s, its service life can be above 10,000hr. The cycle R of lubrication maintenance of SF-2 bush is about the half of its service life. For instance, when PV=25Mpam/s, it is required to be oil-lubricated every 100hr.

DataGradeSF-2SF-2Y(lead   free)
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Max load capacity
    P (N/mm²)
Static   load140140
Dynamic load7070
Max line speed V (m/s)Greaes  lubrica-tion2.52.5
PV value limit (N/mm²·m/s)2.82.8
Friction coef u0.06~0.120.06~0.12
Matching ShaftHardness>270>270
Working temperature(℃)(-60,+120)(-40,+120)
Thermal conductivity (W/mk)5252
Coefficient of linear expansion11×10-6/K11×10-6/K
Pertinence application
It's   used in vehicle chassis, forming machine tools, steel metallurgical   machinery, mineral mountain machinery, hydraulic industry and rolling steel   industry, etc.