What Are the Properties of Oil Lubricants?

While the properties of lubricants can vary significantly, all can be categorised into the following four groups: oils, grease, dry/solid and penetrating. Below, we spotlight the properties of oil lubricants, take a closer look at the benefits of this option and explore some different applications.

What are oil lubricants?

As the name suggests, oil lubricants are generally thin and free flowing, though viscosity can vary between products. They’re made up of long polymer chains, often enhanced with the use of additives such as corrosion inhibitors, antioxidants and detergents. Oil lubricants are widely used on bearings, hinges, blades, gears and other components where metal-to-metal contact is a risk.

• Viscosity - internal resistance to flow

Also known as weight or thickness, viscosity describes internal resistance to flow. The lower the viscosity, the thinner and more fluid the lubricating oil. Unlike heavier greases, low viscosity oil lubricants don’t create resistance. This makes them ideal for applications where efficiency is a priority.

• Demulsibility – resistance to water

Water can wreak havoc on operating systems, making demulsibility one of the most important properties of oil lubricants. This characteristic describes how well a lubricant can separate from oil and shed H20. Oil lubricants with high demulsibility are generally favoured as water can affect a product’s ability to form a protective film and prevent issues such as corrosion.

• Oxidation stability – resistance to contaminants

Oxidation can create major issues for mechanical operators, with contaminants such as acids, water and catalysts accelerating the process. Oxidation stability is used to measure how resistant a lubricant is to these processes.

• Pour point – flow characteristics

The flow characteristics of oil lubricants can have a big impact on overall performance. Pour point is one of several properties assessed when determining the flow characteristics of an oil lubricant relative to temperature. The term describes the lowest temperature at which an oil lubricant continues to flow as a liquid, with additives often used to decrease pour point and improve performance in cold temperatures.

• Flash point – ignition at high temperatures

Flash point is an indicator of both safety and performance, making it one of the most important properties of oil lubricants. It describes the lowest temperature at which an oil lubricant will ignite when exposed to a flame. The higher the flash point, the longer an oil lubricant can resist ignition when temperatures start to climb.

Oil lubricants aren’t the only option available to operators, with grease, dry and penetrating lubricants also widely used. Find out more about these alterative solutions in ‘What Are the Chemical & Physical Properties of Lubricants?’