Lubricant

(redirected from Lubricants)
Also found in: Dictionary, Thesaurus, Medical.
Related to Lubricants: Durex

lubricant

[′lü·brə·kənt]
(materials)
A substance used to reduce friction between parts or objects in relative motion.

Lubricant

 

any of the substances that exhibit a lubricating action. These substances are used in the lubrication of machine parts in relative motion and in the pressure shaping of metals. Substances used as lubricants include oils derived for the most part from petroleum and synthetic oils, greases, solids (graphite, molybdenum disulfide, polymers with fillers), gases (air, vapors of hydrocarbons, halogen derivatives of methane), and surfactants (soaps, glycerol). Lubricants are placed in groups and grades depending on their state of aggegation, properties, and purpose.

REFERENCES

Rozenberg, Iu. A. Vliianie smazochnykh masel na dolgovechnost’ i nadezhnost’ detalei mashin. Moscow, 1970.
Tovarnye nefteprodukty, ikh svoistva i primenenie: Spravochnik. Edited by N. G. Puchkov. Moscow, 1971.
Maiorova, L. A. Tverdye neorganicheskie veshchestva v kachestve vysokotemperaturnykh smazok. Moscow, 1971.

Lubricant

A gas, liquid, or solid used to prevent contact of parts in relative motion, and thereby reduce friction and wear. In many machines, cooling by the lubricant is equally important. The lubricant may also be called upon to prevent rusting and the deposition of solids on close-fitting parts.

Crude petroleum is an excellent source of lubricants because a very wide range of suitable liquids, varying in molecular weight from 150 to over 1000 and in viscosity from light machine oils to heavy gear oils, can be produced by various refining processes (see table). In order to standardize on nomenclature for oils of differing viscosity, the Society of Automotive Engineers (SAE) has established viscosity ranges for the various SAE designations (see table).

It is often desirable to add various chemicals to lubricating oils to improve their physical properties or to obtain some needed improvement in performance. These include viscosity-index improvers, pour-point depressants, antioxidants, anti-wear and friction-reducing additives, and dispersants.

Synthetic lubricants may be superior to mineral lubricants in some applications. The main advantage of synthetics is that they have a greater operating range than a mineral oil. Included in this class are esters, containing oxidation inhibitors and sometimes mild extreme pressure additives, silicones, and the polyglycols, such as polypropylene and ethylene oxides.

Viscosity of oils for various applications
Viscosity in centistokes
Application at 25°C (77°F) Primary function
Engine oils
SAE 10W 60–90 Lubricate piston rings,
SAE 20 90–180 cylinders, valve gear,
SAE 30 180–280 bearings; cool piston;
SAE 40 280–450 prevent deposition on
SAE 50 450–800 metal surfaces
Gear oils Prevent metal contact
SAE 80 100–400 and wear of spur
SAE 90 400–1000 gears, hypoid gears,
SAE 140 1000–2200 worm gears; cool
gear cases
Aviation engine oils 220–700 Same as engine oils
Torque converter fluid 80–140 Lubricate, transmit
power
Hydraulic brake fluid 35 Transmit power
Refrigerator oils 30–260 Lubricate compressor
pump
Steam-turbine oil 55–300 Lubricate reduction
gearing, cool
Steam cylinder oil 1500–3300 Lubricate in presence of
steam at high temperatures

The most useful solid lubricants are those with a layer structure in which the molecular platelets will readily slide over each other. Graphite, molybdenum disulfide, talc, and boron nitride possess this property. A unique type of solid lubricant is provided by the plastic polytetrafluoroethylene (PTFE). The principal difficulty encountered with the use of solid lubricants is that of maintaining an adequate lubricant layer between the sliding metal surfaces.

A lubricating grease is a solid or semifluid lubricant comprising a thickening (or gelling) agent in a liquid lubricant. Other ingredients imparting special properties may be included. An important property of a grease is its solid nature; it has a yield value. This enables grease to retain itself in a bearing assembly without the aid of expensive seals, to provide its own seal against the ingress of moisture and dirt, and to remain on vertical surfaces and protect against moisture corrosion, especially during shut-down periods.

References in periodicals archive ?
In the Lubricant Sector, SK enjoys a enviable position as it is the single largest producer for VHVI Base Oil.
Increase in off shore exploration activities, growth in subsea installations, the growing global energy demand and increasing demand for oil and gas are key driving factors responsible for the growth of the global offshore lubricants market.Increase in demand for oil and gas in the world is one of the primary factors promoting the growth of the global offshore lubricants market.
In February 2019, it also announced its physical expansion into Egypt by setting up a joint venture with Proserv Egypt to sell lubricants in the country.
Not only can using the wrong lubricant lead to asset failure, but it may also void the car's warranty.
Halco Lubricants said the combined resources and experience will allow the company to enhance service and offerings to customers and create improved alignment with suppliers.
H1 lubricants describe greases that be used in applications where accidental food contact may occur but would be limited to a trace amount.
An extensive range of ENOC and Caltex lubricants, greases, coolants and specialty product offerings are available to the market via EPPCO Lubricants, as the company provides product offerings locally for its brands packaged in bulk, drums and small pack cartons.
Q: What are some key advances in food-grade lubricants within the past few years?
The iNTERSPARE Lubricants provides a portfolio of oils, lubricants and sprays which were purposefully optimised for the lubrication of very specific components and possess the corresponding certification.
"Many companies do not consider lubricants as an area where energy savings can be made," explained Phillip Henry, Business Development Manager, The Lubricant Company.
In order to acquire the ignition delay of different lubricants, a high-speed camera captured the injection and combustion process of the lubricants with 10000 frames per second.