An efficient and high-quality lubricant must possess many important characteristics. To remain in their liquid state across a wide range of different operating temperatures, they must typically have a low freezing point and a high boiling point. They also require excellent hydraulic thermal and hydraulic stability and offer a high resistance to both oxidation and corrosive forces.
However, the property considered to be of the utmost importance when it comes to a lubricant is viscosity. In this article, we’ll take a closer look at viscosity and why it is such a vital attribute.
What is viscosity?
In terms of lubrication, viscosity refers to the internal resistance against flow within an oil, fluid or grease. The higher a lubricant’s viscosity is, the slower it will flow. Those seeking a lubricant that creates a film that can stay in place when speeds are lower will always require a product with a higher viscosity.
What role does viscosity perform?
As mentioned, experts agree that viscosity is the most essential property of any lubricant, and therefore an important consideration when purchasing a product for a specific application. Viscosity acts to create a lubricating film, while cooling machine components, sealing parts from unwanted particles and efficiently controlling lubricant consumption. Viscosity must always be balanced for speed, temperature and load in any application.
What is the Viscosity Index?
The Viscosity Index, or VI for short, is the rate of change of the viscosity of an oil with temperature. Essentially, the higher a lubricant’s VI, the less change will occur to an oil’s viscosity under different temperatures.
Varied viscosity for different applications
Some equipment will require a constant flow of lubricant to ensure it operates effectively. Low-viscosity oils will flow easily throughout systems, while higher viscosity oils will flow slower. To stay in place on moving parts of an engine or other mechanical system, a specific level of viscosity is required to make sure it adheres effectively.
Grease is an ideal example of a high-viscosity lubrication solution. While manufactured from a base oil, a thickening agent is added to grease products to ensure they have a more solid appearance and higher viscosity. Unlike oil, which is designed to feed through mechanical systems, grease can be applied to areas and stick to surfaces, providing a long-lasting seal against wear, abrasion, corrosion and contaminants.
Always consult the VI of any lubricant before purchasing an oil or grease to ensure it is suitable for your requirements.
