Considerations for Selecting the Right Grease

Selecting the Right Grease for the Right Job

Posted by Chemtool Team | 03/06/2019

When you need to choose a grease for a specific application, the first step is to consult the owner’s manual or OEM (Original Equipment Manufacturer) for a recommendation. If neither exist, you’ll need to go through a few steps in order to choose the best grease.

First, you need to look at the viscosity of the base oil. Higher viscosity is typically needed in low speed, high load, high temperature and pressure related applications. On the other hand, lower viscosity is typically needed in low temperature, high speed, variable load and pressure applications.

Once the viscosity is determined, you’ll need to look at the base oil type. The base oil can be mineral or synthetic. Mineral base oils can be used in constant temperature applications and synthetic base oils in a wider range of temperatures. The pressure and load are also factors to consider.

The next consideration is the correct grease thickener and thickness/consistency needed. Grease thickeners have distinct attributes such as high or low temperature tolerance, oil separation (or lack thereof), and water tolerance. The thickener is what holds the additized base oil in place and must be able to withstand the conditions of the applications in which it performs. Thickener types vary and should not be mixed. Some popular thickeners include aluminum complex, polyurea, lithium, calcium sulfonate, and lithium complex. Most importantly, the thickener needs to be compatible with the recommendations of the manufacturer of the equipment.

Once the thickener is selected, you can determine the right additive package. Additive packages contain components to handle extreme pressure, anti-wear, rust and oxidation inhibitors, as well as others.

Other considerations are application related performance characteristics. These considerations include oil separation, dropping point, water tolerance and stability (mechanical and thermal) as well as:

  • Bearing speed
  • Storage conditions
  • Shelf life
  • Load (extreme pressure)
  • Bearing type
  • Environment (temperature, water exposure and contamination potential)

As you can see, there are many considerations in choosing the right grease. Not only that, but choosing the right grease makes a big difference. If the wrong grease is used for an application, potential outcomes include: metal to metal contact, excessive wear, increased and even mechanical failure.

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