To Grease or Not To Grease - Whitepaper
Lubricants do more than just prevent wear – they reduce friction, remove heat and prevent rust and corrosion. Selecting the right lubricant, in the right amount, for the right application is critical for a successful operation.
Grease is commonly used when it is not convenient or even practical to use oil. Grease, defined by the American Society for Testing and Materials (ASTM), is “a solid to semifluid product of dispersion of a thickening agent in a lubricant. Other ingredients imparting special properties may be included.” There are three components in grease: base oil (70-95%), thickener (3-30%) and additives (10%). A careful selection of components can have a big impact on performance.
The base oil does the lubrication. Additives can enhance, suppress or add new properties to the existing properties of grease. Thickeners are added to the base oil to produce a solid to semifluid structure and act like a sponge - they hold the components of the grease in place and respond to external forces, like elevated temperatures and pressures, to release the oil to do the lubrication. Thickener technology is one of the most important characteristics when selecting grease.
So why is grease thickener selection so important? Thickener choice is influenced by operating temperatures, load, material compatibility and speed, and are classified as soap or non-soap. Soap thickeners can be simple, mixed or complex. Simple soap thickeners are quite common and are acid-based reactions. Mixed soaps (i.e. lithium/calcium) were developed to improve any shortcomings with simple soaps. Complex soaps are made by combining a conventional soap with a complexing agent and are known for superior temperature resistance. Non-soap thickeners undergo a chemical reaction to form the thickener and provide improved stability.
- Soap Thickeners: Lithium, Lithium Complex, Aluminum Complex, Calcium
- Non-Soap Thickeners: Polyurea, Over-based Calcium Sulfonate, Bentone (Clay)
Lithium Complex thickeners are most widely used due to their long-term work stability and excellent compatibility. Lithium complex thickeners have excellent shear stability, improved thermal resistance, low oil bleed and good low-temperature pumpability. Typical applications include bearings in automotive, agriculture and industrial industries.
Calcium Sulfonate Complex thickeners are known for providing excellent wash- and water-resistance, extreme pressure (EP), anti-wear and corrosion resistance, and exceptional thermal stability. Typical applications include rolling equipment, pulp and paper, marine, mining, construction, automotive and agriculture industries.
Polyurea thickeners are considered to be high performing in high temperature and continuous use bearing applications. Polyurea thickened greases have excellent anti-oxidancy capacity and a high dropping point, as well as excellent thixotropic properties. Typical applications include electric motor bearings and precision ball-bearings.
The Archer Grease line has a premium grease portfolio consisting of Archer Gold Lubri-Plex, a synthetic-blend calcium sulfonate complex technology, Archer Gold Lubri-Shield, a high performing polyurea thickened grease, and Archer Gold Lubri-Tac, a heavy duty lithium complex formulation with 3% molybdenum disulfide. All Archer grease products have a high dropping point in excess of 500 degrees Fahrenheit and a careful selection of additives to protect agriculture, construction, mining, industrial and fleet equipment. Selecting which grease is right for your application may seem complicated, but an Archer Lubricants representative can help guide your decision today.