These lubricants operate in a non-combustion environment. Transmission fluids, hydraulic fluids, gear oils and greases are used for mechanisms that transfer power from a power source, such as an engine, to the parts that perform the actual work, such as the wheels.
Transmission Fluids must have frictional consistency over time (durability) and frictional compatibility with automatic or manual transmission components. Automatic transmissions require OEM specified fluid only, manual transmissions use a variety of fluid specifications. Some transmission fluids need improved shear stability, low-temperature fluidity, and other specific characteristics. Power transmission fluids also demand certain viscosity.
Tractor Lubricants can be roughly classified into two types; UTTO (Universal Tractor Transmission Oil) and STOU (Super Tractor Oil Universal). UTTO oils are used for the tractor transmission and hydraulic systems. STOU oils can be thought of as UTTO oils with engine performance ability, and are used in all parts of a tractor i.e. one oil can satisfy all tractor lubrication requirements. All tractor lubricants need good wear performance for the transmission as well as good frictional performance for the oil-immersed wet brakes and clutches.
Automotive Gear Lubricants must provide extreme pressure protection against fatigue, scoring, pitting and wear for vehicle gears and axles. They must also protect from oxidation and corrosion over the drain period (time between lubricant changes) which can be as high as 500,000km. Note that gear oil viscosity grading is different from engine oil viscosity grading.
SAE J306 gear oil viscosity
|
SAE viscosity grade |
Maximum temperature for viscosity of 150,000 cP, ºC (Brookfield viscosity) |
Low shear rate kinematic viscosity (cSt) at 100ºC, Min. |
Low shear rate kinematic viscosity (cSt) at 100ºC, Max. |
|
70W |
-55 |
4.1 |
|
|
75W |
-40 |
4.1 |
|
|
80W |
-26 |
7.0 |
|
|
85W |
-12 |
11.0 |
|
|
80 |
|
7.0 |
<11.0 |
|
85 |
|
11.0 |
<13.5 |
|
90 |
|
13.5 |
<24.0 |
|
140 |
|
24.0 |
<41.0 |
|
250 |
|
41.0 |
|
Industrial Gear Lubricants need to protect industrial gear sets against wear, scoring and in some cases micropitting (which can lead to pitting). The lubricant also needs to provide corrosion and oxidation protection. Performance is driven by industry standards (DIN, AISE, AGMA, etc.) and also by OEM’s, e.g. Flender.
Turbine Lubricants are used to lubricate the bearings, hydraulic system and seals, and reduction gearbox if present, of a turbine. Their most important function is to remove heat from the bearings that support the turbine shaft. They must also offer protection from rust, corrosion and sludging, good frictional characteristics and, where a reduction gearbox is present, protection from wear. The lubricants must remain effective for up to 20 years, as this is the average gap between the overhauls that include lubricant changes.
Power Steering Fluids quality is assessed on the basis of frictional properties, seal compatibility, oxidation resistance, and rust control. Some automatic transmission fluids are also appropriate for this application.
Shock Absorber Fluids require good frictional characteristics, oxidation resistance, wear protection and seal compatibility. Compressibility and antifoaming characteristics are also desirable.
Hydraulic Fluids are of two general types: for mobile hydraulics (excavators, dumper trucks, etc.) and for industrial hydraulic equipment. Such fluids include; antiwear hydraulic fluids, fire-resistant fluids, and rust and oxidation-inhibited oils (R&O oils). Each hydraulic pump manufacturer has its own performance requirements governing viscosity, antiwear properties, and ability to inhibit rust, oxidation, corrosion, foam, filter plugging, and demulsibility. There are also industry standards that define the basic performance requirements.
Slideway Lubricants are used to lubricate the moving track of a machine tool. Their main functions are wear and corrosion protection, as well as reducing the static and dynamic friction between the machine tool and the base.
There are two main types of slideway lubricant; slideway-only, and multifunctional. The latter type also provides some hydraulic and industrial gear performance ability. Separation of the lubricant from water-based cutting fluids is also essential.
Miscellaneous Industrial Oils include metalworking fluids, rock drill oils, quench oils, compressor oils, etc.
Greases are classified by chemical composition and many other properties. They are commonly identified by the type of thickener used, consistency and service classification.