The properties and characteristics of any hydraulic oil are vitally important to the capability of your hydraulic system to work within the operating conditions you need to use it in. This is especially true of industrial or commercial hydraulic oils. So, for a hydraulic oil to be useful it needs to have the below properties:
Non-compressible
Thermally stable, within a range of operating temperatures
Fire resistance
Non-corrosive to its system
Anti-wearing to its system
Low tendency to cavitate
Tolerance to water (resistance to water contamination)
Total water rejection
Constant viscosity, regardless of temperature
Long life
Cost-effective
The contents of hydraulic oil
Hydraulic oil is made from a variety of different ingredients, with one base fluid. These ingredients can often be mixed depending on the type of oil you require.
Generally speaking, hydraulic liquids are made up of:
Mineral oil
Esters
Glycol
Silicone
Ethers
Esters
Some other chemicals which are hard to pronounce!