SKF Lubricants
 
The perfect solution for every application
 
Even the very best bearing can only show optimum performance when it is lubricated correctly. Here, it is extremely important to choose the right bearing grease and to apply the most suitable lubrication intervals and methods. This realisation has prompted SKF, the world's leading manufacturer of rolling bearings, to look intensively into the subject of lubrication. SKF engineers consider grease to be a "fundamental" component of the bearing arrangement and thus, as important as the bearing, housing and sealing. SKF's vast experience in the development of rolling bearings forms the basis for the development of a special range of lubricants, the superior quality of which is obtained through continuous testing and studies.

The strict standards and testing parameters developed and applied at the SKF Engineering and Research Centre have become internationally recognised benchmarks for bearing greases. The comprehensive range of SKF bearing greases is the result of many decades of research and development. Each individual lubricant is precisely adjusted to the respective field of application.
 
 
SKF sets the standard
Tangible performance parameters mean more to SKF than the chemical composition of the lubricant. The chemical composition is not the only factor in determining the quality of a particular grease, since modern lubricants are extremely complex. SKF has set the standards for developing special testing parameters.
 
Bearing grease selection
Incorrect lubrication accounts for up to 36 % of premature bearing failures. All–purpose greases are inadequate for specialised bearing needs and can cause problems rather than be beneficial. Bearing applications have wide variations of operating conditions and correct lubrication calls for matching the grease precisely to the application.
 
Bearing greases help ensure smooth, trouble–free operation and maximum reliability even under the most extreme conditions. They help prevent contamination from penetrating the bearing, cushion any shock loads and protect against corrosion. Selecting the right bearing grease for a certain application is essential for achieving the maximum service life of a bearing.
 
Selection criteria for correct lubrication include bearing type and size, temperatures, speeds and loads, as well as the desired service life and re–lubrication intervals.
 
 
SKF Traffic light concept and Grease Performance Factor
The temperature range over which a grease can be used depends largely on the type of base oil and thickener used as well as the additives. The relevant temperatures are schematically illustrated in the following diagrams in the form of a “double traffic light”.
 
Operating temperature range of greases:
The SKF Traffic Light Concept
 
 
LTL – Low–temperature limit:
The lowest temperature at which the grease will allow the bearing to be started up without difficulty.

LTPL – Low–temperature performance limit:
Below this limit, the supply of grease to the contact surfaces of rolling elements and raceways may become insufficient. Values are different for roller and ball bearings.

HTPL – High–temperature performance limit:
Above this limit the grease will oxidise in an uncontrolled way, so that grease life cannot be determined accurately.

HTL – High–temperature limit:
When exceeding this limit, the grease loses its structure permanently (e.g., the dropping point for soap–base greases).
 
 
Effect of temperature on grease functioning
The values shown in these diagrams are based on extensive tests conducted in SKF laboratories. These tests allow us to accurately determine the temperature range of the SKF bearing greases given in the selection charts included in this catalogue.

The results of these tests are also used to evaluate the grease life. The performance of each grease is then translated into a Grease Performance Factor (GPF). Greases with highest values offer the longest life. This factor, used in correlation with the SKF re–lubrication diagram (see SKF General Catalogue GC 5000), allows you to determine the correct re–lubrication intervals for the chosen grease.

 
 
Re–lubrication intervals
Choosing the right bearing grease for a certain application is critical to bearing performance. Applying the correct quantity of grease at the right intervals is of equal importance. Over– or under–greasing as well as inadequate lubrication methods can shorten the bearing’s service life. For determining the right amount of grease and the correct re–lubrication intervals for a specific application, SKF has developed DialSet, a simple computerised re–lubrication calculation program. Calculated re–lubrication intervals are based on the latest lubrication theories published in the SKF General Catalogue (GC 5000) and depend on bearing type used, application conditions and properties of selected bearing grease.
 
Lubrication methods
The lubrication method used is equally important to the right bearing grease, quantity and lubrication intervals. Using lubricators, manual or automatic, facilitates proper lubricant supply to the application. Maintaining cleanliness when lubricating bearings is crucial, as contamination can cause the bearing to fail prematurely.

Using a grease meter in combination with a grease gun or pump during manual lubrication helps ensure the supply of the right quantity of grease. SKF’s range of grease guns, pumps and lubrication accessories is designed for contamination–free grease supply as well as ease–of–use.

Continuous lubrication using automatic lubricators, single or multiple–point, provides the application with consistent and controlled supply of bearing grease. This reduces the risk of over– or under–greasing and positively contributes to optimising the bearing’s service life. Additionally, automatic re–lubrication reduces the risk of contamination. Around the clock solutions offered by SKF, such as SYSTEM 24 and SYSTEM MultiPoint, provide precise and reliable grease supply, exactly adjusted to the application’s needs.