What is Hydraulic Oil?

Hydraulics represent systems where energy and power are transferred through fluids. The fluids applied are called hydraulic fluids or hydraulic oils and are used in various types of machinery, equipment, and across industries. Moreover, hydraulic systems and components are applied in agriculture, construction, mining, steel, shipbuilding, aviation, aerospace industry, chemicals, medicine, food, environmental technology, and more. Name any industry in the world and there is a very high chance that it uses a type of fluid technology in stationary or mobile applications.

What is Hydraulic Oil?

One of the primary functions of hydraulic oil is to transmit power or energy. However, this is not its only function. Some of its primary functions include:

• Transferring pressure and motion energy
• Transferring forces and moments when used as a lubricant
• Minimization of wear to sliding surfaces under boundary friction
• conditions
• Minimization of friction
• Protection of components against corrosion (ferrous and non-ferrous metals)
• Dissipation of heat
• Suitability for a wide range of temperatures, good viscosity-
• temperature behavior
• Prolonging the life of machinery

However, hydraulic oils also have secondary and tertiary functions.

Some of the secondary characteristics of hydraulic oils include high aging stability, good thermal stability, inertness to materials, compatibility with metals and elastomers, good air separation, low foaming, good filterability, good water release, good shear stability (in the case of non-Newtonian fluids), and more.

On the other hand, some of the tertiary characteristics include low evaporation due to low vapor pressure, toxicologically harmless, ecologically safe, and low flammability (fire resistance), all of which depend on how the fluid is formulated.

What is hydraulic oil used for?

As well as to transfer power, hydraulic oils also serve as a lubricant, coolant and sealant in machinery and equipment. They are used in pretty much every industry due to their large number of benefits; hydraulic application examples include:

• Forklift trucks and stackers – to power the forks which lift heavy goods
• Wood (log) splitters – to power the ram mechanism on a hydraulic oil log splitter
• Agricultural machinery and vehicles – to operate the hydraulic brakes and hydraulic systems such as boom arms
• Aircraft – hydraulic oil must be reliable for control systems, aircraft hangar doors, aircraft jacks and aircraft controls
• Automotive lifts – car lifts and car jacks require hydraulic jack oil to provide safety as well as performance
• Nautical – for marine vessel stabilisers to reduce the amount of oil which can affect a ship’s balance and cause sea sickness
• Snow ploughs – an essential component in the operation of the hydraulic lift, tilt and angle movements, and blended with anti-freeze additives
• Construction – used in a range of light, mid and heavy duty construction machinery such as cranes, excavators and tipper trucks

Is there a difference between hydraulic oil and hydraulic fluid?

Although hydraulic oil and hydraulic fluid are terms that are often used interchangeably, there are some subtle differences.

Hydraulic fluid has the same uses as hydraulic oil, however it is more commonly used in aircraft and automobile systems such as automatic transmissions, power brakes and steering.