Tribologie

a

ACEA

Association des Constructeurs Europeéns d’Automobiles.

Successor organisation of CCMC and CLCA. Represents the European automobile industry in respect of operating supplies (fuel and lubricants). The specifications originally issued by the CCMC (organisation that proceeded the ACEA) are still valid: G 4, G 5, D 4, D 5 and PD 2. (See CCMC.)

ACTIVE INGREDIENTS (ADDITIVES)

Additives which are added to mineral oils, mineral oil products and synthetic oils

as substances soluble in oil. As a result of a chemical and/or physical effect, they change or improve the characteristics of lubricants, fuels, heating oils, etc. in respect of characteristics such as oxidation stability, flow characteristics and anti-knock properties.

ADDITIVES

Oil-soluble substances added to lubricants to obtain and optimise certain characteristics. For example, through their chemical or physical action they influence: viscosity temperature characteristics, pour point, flow characteristics, oxidation stability, foam formation, detergent action etc.

AGEING

Undesired chemical change in mineral and synthetic products during use and storage.

AGEING CHARACTERISTICS

These are used to assess the length of time for which lubricating oil can be used for the specific application.

AGMA SPECIFICATIONS

American Gear Manufacturers Association. Lubrication recommendations for open and closed industrial gear units. Classification into nine viscosity grades.

AIR FILTER OILS

Odour-free and ageing-resistant oils for cleaning the air intake (20 – 100 mm2/s40). White oils must be used for special systems.

ALUMINIUM COMPLEX LUBRICATING GREASES

are highly resistant to water, are easy to handle and hardly exude any oil. Have a high dropping point (to over 230°C) and good high-pressure characteristics. Application temperatures up to approx. 160°C.

ANTI-KNOCK RESISTANCE

It specifies the performance (resistance) of a spark-ignition engine in respect of detonation during combustion in the engine: DIN 51 756 P 1 to P 6, RON (Research Octane Number), MON (Motor Octane Number), FON (Front Octane Number) and ROON (Road Octane Number).

ANTI-WEAR ADDITIVES

Active ingredients which aim to reduce wear in mixed friction areas; a distinction is made between:

a) Mild-acting additives such as fatty acids, fatty oils (highly polar, surface-active substances), metal dithiophosphates, etc.

b) High-pressure additives made of lead, sulphur, chlorine, phosphorous connections, etc.

c) Solid lubricants such as graphite, molybdenum disulphide, etc. – see EP additives.

ANTIFREEZE

Coolant, which in its concentrated form contains approx. 90% ethylene glycol and propylene glycol, inhibitors, additives, colorants and a very small amount of water. Specifications for coolant are what are termed company specifications stipulated by the individual vehicle manufacturers. They also specify the mixing ratios.

ANTIOXIDANTS

Chemical additives that slow down the ageing of oil considerably.

API

The American Petroleum Institute classifies the requirements of various American engine manufacturers into a system of service categories (classifications). These differentiate between gear oils for passenger cars, engine oils for spark-ignition engines and diesel engine oils.

The American Petroleum Institute uses the following service categories:

API classification for engine oil (commercial categories)
Engine oils for diesel engines are classified into CA to CG categories. For these lubricant categories, too, the same evolution can be seen as for the service classes. Today we are particularly interested in CD categories for heavy duty diesel engines with and without turbocharging, CE for very heavy duty and high-speed diesel engines with and without turbocharging and sharply fluctuating loads. After 1994 CD was superseded by CF. The newly created CF-2 for two-stroke diesel engines and the CF-4 specification, which supersedes CE and defines additional values such as those that relate to volatility loss and piston cleanliness, are of interest. Since June 1994 the CG specification has also included emissions limits for the latest generation of engines.

API classification for engine oil (service categories)
These specifications are very common.
Engine oils for spark-ignition (petrol) engines are classified in the categories SA to SH. SA generation products hardly used to contain any additives (non-compounded). The subsequent SB and SC generations contained mild compounds with active substances to prevent carbonisation, cold sludge, ageing, corrosion and wear. In 1968 the SD category satisfied the increased demands of the vehicle manufacturers. The next generations of SE, SF and SG engine oils for the toughest requirements met the requirements for more powerful engines and new traffic situations (stop-and-go traffic) in the 1970s and 1980s. Since 1993 the SH specification has been used. This also specifies the volatility loss (NOACK), filterability, foaming behaviour and flash point.

API classification for passenger car gear lubricants
Gear oils rated GL 1 to GL 5. A product with the required rating is used depending on the application, design of the gear mechanism and the load. For instance, GL1 is a non-compounded oil for gear trains and worm gears as well as helically toothed and spiral-cut final drives with minimal loads. Nowadays the greatest demand in the market is for GL 4 and GL 5 specifications. The GL 5 rating covers gear oils for highly loaded hypoid axle drives and, in some cases manual and special gearboxes as well. GL 6 oils for very highly loaded final drives have now been withdrawn.

AROMATIC HYDROCARBONS

Hydrocarbon compounds with cyclic molecular structures. They produce viscosity temperature characteristics (see VI) in lubricants and have a bad effect on resistance to oxidation. Added to fuel for spark-ignition engines to prevent combustion knock. The percentages added are increasingly being limited on account of their carcinogenic effect.

ASH

Mineral deposits that remain after lubricants have been burnt, in the form of oxides (oxide ash) or sulphate (sulphate ash after sulphuric acid has been added).

ASPHALT

A mixture made of bitumen and mineral building materials (sand etc.).

AUTOMATIC TRANSMISSION FLUID (ATF)

ATFs are special lubricants with specific and high requirements for automatic transmissions. What are required are very good temperature characteristics and shear stability, high oxidation stability and excellent anti-foaming properties and air release characteristics. The specifications currently used are very extensive. Here are the most recent ones: GM Dexron III, FORD Mercon, MB 236.8, etc.

AVIATION LUBRICANT

Aviation lubricant which is adapted to the special requirements of the aircraft engine through its processing and composition. Mainly synthetic oils.

b

BACTERIA INFESTATION

Coolants mixed with water (e.g. emulsions) provide good nutrients for bacteria, yeasts and fungus. Bactericides protect the emulsion from infestation by bacteria, which may also manifest itself in the form of unpleasant odours, corrosion of workpieces, a reduction in the pH value, etc.

BARIUM-COMPLEX LUBRICATING GREASES

Lubricating greases with good high-pressure characteristics and high resistance to water.

BARIUM-SOAP LUBRICANTS

Lubricants made of barium soaps and mineral or synthetic oils. Highly water repellent, good shear stability, but generally have poor low-temperature characteristics.

BARREL

The barrel is an international capacity measure which has been used in the mineral oil sector since the start of oil production. Production output and prices are set in barrels or dollars per barrel. 1 Barrel = 42 US gallons = 159 Litres.

BASE OILS

Important content of mineral and synthetic oils in mixed or compounded lubricants such as engine and gear oils or in products such as lubricating greases. The type and quantity of base oils are decisive for characteristics such as viscosity temperature characteristics, resistance to oxidation, response to additives, etc.

BATCH BLENDING

Mixing and adding of mineral and synthetic oil products in heatable mixing vessels with agitators (MOTOREX mixer: 0.3 – 20 m3). The temperature must be selected so that all parts to be mixed are distributed uniformly and yet still no undesired reactions occur.

BENTONITE

Minerals (e.g. aluminum silicate, montmorillonite, etc.), which act as thickeners for the manufacture of temperature-resistant lubricants with good refrigerating characteristics.

BENZIN

These are petroleum oil hydrocarbons in the boiling range of approx. 25°C to approx. 215°C. They are divided into:

A. Raw gasoline (naphtha)
Feedstocks for petrochemicals and intermediate products such as ethylenes, propylenes, etc.

B. Special and test benzin
For various applications such as for cleaning agents, solvents, benzin for chemical preparatory and analytical purposes, etc.

C. Engine benzin
Fuel (chain and cyclic hydrocarbon mixtures) produced for spark-ignition engines using special refining methods, with the familiar qualities available at service stations.

D. Aircraft turbine fuels
For jet engines (jets, turbines), also called kerosene.

E. Aviation fuel
For aircraft with piston engines (sports aircraft)

BENZOLE

Cyclic hydrocarbon produced as a distillation product when coking bituminous coal or also during cracking processes (see cracking process).

BIOLOGICALLY DEGRADABLE LUBRICANT

This means the biochemical decomposition of organic chemical compounds accelerated by microorganisms. Microorganisms such as bacteria, fungi, protozoa, etc. bring about biological degradation through what is termed bio-oxidation. This occurs in several stages, producing CO2, water, protein cell material and multiplication of micro-organisms. At the present time, there are three groups of lubricants that can be broken down quickly biologically: Polyethylene glycol, vegetable oils and certain synthetic esters. They serve as a basis for two-stroke, chain, release, lubricating and hydraulic oils and greases, etc.

BITUMEN

It is produced during the environmentally compatible processing of crude oils (residue of vacuum distillation). Dark-coloured, semi-solid, meltable, high-molecular hydrocarbon mixtures. Bitumen is used in asphalt and as an insulating material, etc.

BLANK HARDENING OILS

High-quality refined products that are highly resistant to ageing, non-compounded or inhibited, which do not deposit any residues on the workpiece.

BLEEDING

The lubricating oil contained in lubricating grease is separated from the soap skeleton. Bleeding of grease at the lubricating point may mean that the grease is not stable enough in use and/or is not temperature-resistant.

BLENDING

Refining mineral oil products by means of additives, in accordance with a formula. The delicate mixing process is undertaken in a tank or vessel as "batch blending" or in computer-controlling mixing systems over 2 to 5 hours at temperatures of between 60 and 110 °C.

BLOWN OILS

Rich oils blown with hot air at temperatures of approx. 80 to 120°C, thus enlarging the molecules and thickening the oil.

BOUNDARY FRICTION

Occurs if the lubricating film is broken or destroyed during friction. Two mating surfaces of materials make contact as a result of conditions that promote friction such as pressure or speed. Boundary friction cannot be avoided before a load-carrying lubricating film is formed during start-up and shutdown and when the direction of rotation changes.

BREAK-IN OILS

Lubricating oils for running in new machines, engines, etc. so that roughness points can be smoothed or evened out via chemical/physical processes in as controlled a manner as possible, so that a larger percentage of contact area can be achieved for the surfaces that slide against each other.

BRIGHT STOCK

Highly viscous, refined light residue of lubricating oil. Possesses a very good lubricating action and is a mixing component in lubricating oils.

BURNING POINT

Lowest temperature, referred to a certain pressure, at which the vapours of a uniformly warmed fluid continue to burn for a further five seconds after ignition by a flame: DIN ISO 2592

BURNISHING OILS

a) Oil for removing salt deposited on workpieces made of burnishing salt solutions

b) Oil for blackening the surface of steel parts

BUTANE

Hydrocarbon C4H10 that is a gas at a normal temperature: DIN 51 622

c

CABLE OILS

Highly viscous mineral oils for impregnating insulating paper for high-voltage cables; sometimes mixed with waxes, bitumen, resins and pitch (filling compound).

CATALYSTS

a) Substances which cause a chemical reaction (acceleration, retardation, direction) in other substances without the catalyst itself changing. In the petroleum industry, generally solid catalysts are used, e.g. cobalt, molybdenum, platinum, nickel, etc.

b) Catalytic converters for combustion engines: when used in conjunction with a Lamda sensor and a control unit, this changes harmful emissions in exhaust gas (hydrocarbons CH, nitrous oxide NO and carbon monoxide CO) into non-polluting emissions (water vapour H2O, carbon dioxide CO2 and nitrogen N).

CAVITATION

Cavities can be formed if, as a result of flow or vibration, the vacuum in a unit falls below the vapour pressure of the fluid used. When the vacuum drops, the microscopic bubbles that have formed suddenly liquefy (implode): This causes the destruction of metals, bearings, gear wheels, etc.

CENTIPOSE (cP)

Unit of dynamic viscosity.

(1 cP = 1 mPa s)

CENTISTOKE (cSt)

Unit of cinematic viscosity.

(1 cSt = 1 mm2/s)

d

DEFOAMANTS

Lubricant and coolant additives to prevent foaming.

DEGREE OF DISPERSION

Is the fineness of particle size in a dispersion. The more transparent the size of particles in a dispersion, the more transparent it appears. For coolant emulsions/suspensions the particle size is between 0.1 and 10 µm, depending on the type.

DEMULSIFICATION CAPACITY

Characteristic of mineral oil products and synthetic products to separate out water (resistance to emulsification).

DEMULSIFIERS

Anion-active compounds such as alkali salts or alkaline-earth salts. Demulsifiers must be used to prevent the binding of in some cases very stable water-in-oil emulsions by the ingress of water into certain lubricating oils.

DEMULSIFYING CAPACITY

Ability of lubricating oils to eliminate water or to prevent mixing (emulsion). The demulsifying capability of lubricating oils and mineral-oil-based hydraulic fluids is tested in accordance with DIN 51 599. Demulsifying characteristics: DIN ISO E 6614

DEPOSITS

Particles of soot or dirt, produced as a result of oil ageing, mechanical wear, combustion residues, high thermal loads. These occur in the combustion chamber, filters, the oil sump and at parts exposed to high thermal loads.

DETERGENT AND DISPERSANT ADDITIVES (D/D)

Succinimides, neutral metal sulphonates, phosphates, polymer detergents, etc. – the purpose of these additives in engine oils (HP active ingredients) is to stop combustion residues that are not soluble in oil (soot, coke, etc.) and oxidation products containing resin and asphalt from clumping together, remaining in suspension, thus preventing sludge deposits and the oil from thickening.

DIN

Deutsches Institut für Normung e. V. (German Standards Institute): For mineral oil products, standards on characteristics, requirements and test procedures for manufacturers, users and consumers.

DISTILLATION

When crude oil and mineral oil initial products are distilled, the various hydrocarbon mixtures are split in fractionating columns after evaporation and subsequent condensation, i.e. physical separation, and divided into certain boiling ranges (fractions). One must differentiate between two distillation types:

  1. Atmospheric distillation
    The crude oil heated to max. 360°C is routed to the fractionating column. The hydrocarbon gases flowing upwards then condensate in bubble trays arranged one above the other. Several bubble trays, termed fractions (boiling ranges), are then removed together. The products from atmospheric distillation are light and heavy benzine, petroleum, gas oil and a residue.
  2. Vacuum distillation
    The residue of atmospheric distillation is heated to approx. 360°C and routed to a fractionating column under vacuum. The products are various lubricating oil distillation fractions such as light and heavy spindle oils, cylinder oils, vacuum residue to manufacture bright stock, bitumen, heavy heating oil, etc.

DOT

Department of Transport; specifies the regulations for DOT 3, 4 and 5 brake fluid.

DRAWING GREASE, DRAWING OIL

Lubricant for drawing metals, in some cases with high-pressure additives, greased and emulsifying in use.

DRILLING OILS

Mineral oils emulsified with water to manufacture emulsions (mineral oil + emulsifier + stabiliser) for use as a metalworking fluid.

DROPPING POINT

The dropping point is the temperature at which a specimen flows through the opening of a nipple when warmed under test conditions and falls on the floor of the test pipe; for lubricating greases: DIN ISO 2176).

DUO-SOL PROCESS

Selective removal (solvent extraction) of fluid through two solvents. Undesirable constituents such as aromatic hydrocarbons, resins and other instable compounds can be removed in this way.

e

EMCOR TEST

This Emcor process is used to test what protection lubricating greases in roller contact bearings, plain bearings and sliding surfaces provide for the material in the presence of water, under conditions that are as close to actual operating conditions as possible. DIN 51 802.

EMISSIONS

Contaminants discharged into the atmosphere from chimneys, exhaust systems, etc. and cause air pollution.

EMULSIFIABILITY

The propensity of a synthetic or mineral oil or a compounded oil to form an emulsion with water.

EMULSIFIERS

Fatty acids, grease soaps, ammonium salts, sulphonic acids, naphthenic acids, etc.; they are classified as anionic, cationic and non-ionizing emulsifiers. Emulsifiers are surface-active substances which promote the formation and stability of an emulsion through reducing the surface tension of water. A distinction is made between oil-in-water emulsions (most common) and water-in-oil emulsions.

EMULSION

Mixture of non-soluble substances; mineral oil with water, for instance, with the help of emulsifiers; it generally takes the form of oil-in-water emulsion but it may possibly also be a water-in-oil emulsion.

ENGINE OIL

This is used to lubricate bearings, engines, cylinders and the valve timing gears in vehicles with internal combustion engines. Engine oils are classified into various viscosity grades (SAE classifications); there are compounded and non-compounded engine oils which, depending on their compounding grade, satisfy various specifications (e.g. MIL, ACEA) and classifications (e.g. API).

ENGLER (E)

Conventional measure to indicate viscosity, what is measured is the efflux time of an oil from a certain flask; the ratio between the relative oil efflux time to the water efflux time at 20°C is the Engler degree.

EP LUBRICANTS

Extreme Pressure lubricants; in the case of lubricating oils or lubricating greases which contain EP active ingredients (polar or metal-active additives or solid lubricants, etc.) in order to allow higher loads to be absorbed, e.g. in engine, gear (hypoid), hydraulic, cutting oils, etc.

ESTER

Compounds formed by the bonding of acids and alcohols and by the elimination of water (aldol condensation or oxo synthesis). Higher-alcohol esters with bivalent fatty acids form what are termed ester oils; synthetic lubricating oils which, depending on their type, have certain advantages over mineral lubricating oils.

EXTREME PRESSURE (EP) HIGH-PRESSURE ADDITIVES

Organic phosphate, chlorine, sulphur and nitrogen compounds, etc., to allow higher loads to be absorbed and to reduce wear in mixed friction areas. Additives called EP additives are added to oils such as gear, engine, hydraulic and cutting oils. These prevent wear and improve the sliding properties of metal surfaces that move against each other.

f

FLASH POINT

This is the lowest temperature at which a fluid to be tested develops vapours in an open or closed flash cup under specified conditions so that a vapour-air mixture develops to burst into flame in the flash cup as a result of external ignition. It then flares briefly and extinguishes again. DIN 51 755 P2, DIN ISO 2592, DIN pr EN 57 – also see burning point.

FLOCCULATION POINT

Is the temperature in °C for refrigerating equipment oils, at which the first deposits can be seen in transmitted light in the form of milky turbidity or flocks, when cooling down in a homogenous mixture of refrigerating equipment oil and refrigerant at a ratio of 10 to 90 (parts by volume): DIN 51 351.

FLOW PROPERTIES

The viscosity properties of individual substances can be shown in flow curves (rheograms showing the relationship between speed gradients and shearing stress) or viscosity curves (shows viscosity h to shearing stress). The form of flow properties depends on the type of substance, e.g. mineral oils, synthetic fluids, lubricating greases, etc.

FLUIDITY

Properties of lubricating oils (fluidity) at temperatures below 0°C. Determination of fluidity (procedure using U-tube). DIN 51 568.

FOAM SUPPRESSOR

Polysilicone (silicone polymers), polyethylene glycol, etc. reduce the tendency to foam during vigorous movement, better foam release; promote the formation of larger air bubbles that dissipate rapidly. The formation of foam has a substantial detrimental effect on the lubricating properties (oxidation, pressure behaviour, etc.) of a lubricant. For this reason, foam formation must be specifically suppressed.

FOAMING TENDENCY OF MINERAL OILS

The quantity (ml) of oil foam produced under specified conditions (blowing through air) indicates the tendency of an oil to foam. To determine the air release characteristics: DIN 51 381. Determination of foaming behaviour: DIN E 51 566.

FORMWORK OILS

Emulsifiable or non-emulsfiable oil for concrete formwork. Requirements vary greatly depending on the formwork material, the porosity of the concrete, concrete type, etc.

FOUR-BALL APPARATUS

Oil tester for checking lubricants with active ingredients (EP lubricants). There are four balls arranged in the shape of a pyramid. The ball on top turns and loading can be increased until the balls fuse together (fusing. load); the loading in N is used as the wear index. DIN 51 350 P 1 / P 2 / P 3

FRACTIONS

Hydrocarbon mixtures with different boiling ranges for atmospheric and vacuum distillation. See distillation.

FRICTION

If the mating surfaces of materials move against each other, a distinction is made between the following friction situations:
a) Dry friction – Boundary friction (starting friction, solid friction, surface layer friction).
b) Semi-fluid friction – mixed friction (from boundary friction to viscous friction).
c) Fluid friction – viscous friction (hydrodynamic friction).

FRICTION MODIFIER (FM)

Fatty acids, fatty acid derivatives, organic amines, amine phosphates, mild EP additives, etc. are called friction modifiers. Their role is to reduce frictional losses or create defined friction behaviour of various lubricants.

FUELS

All gaseous and liquid flammable substances that are suitable for the operation of internal combustion engines: refinery gas, coal gas, sewage gas, natural gas, compressed gas, propellant gas, generator gas, petrol, tractor fuel, diesel fuel and aviation fuel, etc.

FULL LUBRICATION

For instance, elastohydrodynamic lubrication in the case of matching gears or hydrodynamic lubrication for plain bearings where the surfaces that slide on each other are completely separated by the lubricant.

FURFUROL PROCESS

Selective extraction of fluids, in particular mineral oils, using furfurol. Also, see duo-sol process.

g

GALLONS

Capacity measure, English gallons = 4.54 litres, American gallons = 3.79 litres.

GAS ENGINE OILS

Engine oils compounded specially for the specific characteristics and in some cases aggressive constituents of various gases (sewage, natural and refinery gases, propane/butane, etc).

GASOLINE

a) American designation for petrol

b) Light gasoline with a boiling range of approx. 30 to 80°C

GEAR GREASES

Fluid greases for gears, mostly with sodium soap but also with Al and Ca soap greases, fibrous soft to semi-fluid greases (NLGI 0, 00, 000, and 1) for gears and gear motors with simple shaft seals, in some cases EP-compounded; DIN 51 826 consistency classification for lubricating greases DIN 51 818.

GEAR WHEEL GREASE

Lubricant with good adhesive properties, generally for open gear wheel drives, with a bituminous base; often addition of MoS2 and graphite. Generally diluted before application, also available in spray cans for easier application.

GLYCOLS

Bivalent alcohols, e.g. ethylene glycol as anti-freeze for radiators or certain polyglycols for lubricating aircraft engines.

GRAPHITE GREASES

Lubricating greases with graphite added.

GRINDING OIL

Coolant to grind metal surfaces, generally emulsifiable and set to the special requirements of the grinding operation.

GROSS CALORIFIC VALUE (Ho)

Is the quotient from the amount of heat produced by completely burning a certain quantity of fuel: DIN 5499; 51900 P1/P2/P3.

h

HLPD

Are hydraulic oils with detergent additives.

HYDRODYNAMIC LUBRICATION

This exists if, when moving, the sliding surfaces are completely separated by a lubricating film.

HYDROGENATION

This is the term used for the process to add hydrogen to a chemical compound, causing energy to be released, e.g. adding hydrogen to carbon or hydrocarbon compounds, improving middle distillates, lubricating oils, etc.; destructive hydrogenation is the process that breaks up heavy oils into lighter hydrocarbon compounds by adding hydrogen.

HYPOID GEAR OILS

High-pressure lubricating oils with EP additives to improve the lubricating performance and to avoid the likelihood of corrosion; mainly used for final drives in vehicles with spiral-tooth and hypoid bevel-gear drives.

i

INHIBITORS

Anti-ageing agents (retarding agents) which slow down or prevent certain reactions, are used in fuel and lubricants to prevent ageing and corrosion processes.

ISO

International Organisation for Standardisation. The organisation classifies lubricants, industrial oils and related products (Class L). This classification consists of 18 families in which the products are assigned letters A to Z depending on their use. In addition to this, the ISO viscosity classification for industrial lubricants defines 18 viscosity classes in the range from 2 to 1500 mm2/s at 40°C.

k

KEROSENE

English designation for petroleum and aviation fuel (jet engine fuel). Classified into various quality grades (JP 1 to JP 8).

l

LANOLIN

Purified wool fat from sheep used as an ointment base for cosmetics, to grease textiles and leather goods and to protect against rust.

LIGHT GASOLINE

Boiling fraction of petrol up to approx. 100°C.

LIGHT OILS

a) Customs definition for low-boiling mineral oils (petroleum, benzin, test benzin).
b) Tar oils with a specific weight of approx. 0.930 kg/l.

LIME SOAP LUBRICATING GREASE

Lubricating greases containing calcium and therefore highly water repellent are suitable as grease for crank handles, roller grease, hydraulic lubricating grease, axle bearing grease from –20°C to 70°C.

LIMITED SLIP

LS active ingredients are, for instance, used in hypoid gearbox oils for lockable differentials and ATFs (see friction modifiers).

LITHIUM LUBRICATING GREASES

Lubricating greases are produced by saponification of oils with lithium 12 hydroxystearate; they have good water resistance and can be used over a large temperature range; they are generally compounded with AO, AC and EP active ingredients and are often called multi-purpose greases. High dropping point, application temperature – 25° to 130°C.

LOW-TEMPERATURE BEHAVIOUR

For mineral oil products - see cloud point, flow properties, flocculation point and pour point.

LUBRICANTS

Have the task of reducing friction and wear when two points, lines or surfaces move on top of each other and have sliding or rolling contact. A distinction is made between fluid, plastic solid, solid and gaseous lubricants.

LUBRICATING ACTION

Indicates the load-bearing capacity of the film produced by a lubricant. It must always be linked to actual conditions such as the type of friction, the friction situation, mating surfaces of materials where friction occurs, lubrication of the contact surfaces, speed and temperature.

LUBRICATING GREASES

They are consistent mixtures of thickeners and oils. A distinction is made between:

a) Metal lubricating soaps (calcium, Al, Ba, Li, Na and complex lubricating greases, etc.) composed of fatty acids and lyes of metal soaps (thickeners and swelling agents) as well as lubricating oils. Metal soaps, lubricating oils and the manufacturing process determine the structure, consistency, suitability for use and application.

b) Soap-free lubricating greases with inorganic gel-forming agents (gelatinous silica, silica gel, bentonite, etc.) or organic thickening agents (polyethylene, polypropylene, polyurea, etc.) and lubricating oils.

c) Synthetic lubricating greases which consist of organic and inorganic thickening agents and synthetic oils (ester, silicone, polyglycol and polyphenylether oils, etc.).

LUBRICATING PLAN

Precise lubricating instructions with maintenance instructions, designation of lubricating points, the type and quantity of lubricants, intervals, etc. for the individual machine types and their units.

m

MARINE DIESEL ENGINE OILS

Various marine diesel engine oils are used for ships that sail on the high seas. The type depends on the engine type, engine speed, operation and fuel:

a) Engine oils in accordance with API CD can be used for stationary diesel engines and fast-running trunk piston diesel engines and for operation with diesel fuel.

b) Marine diesel engine oils with very good detergent-dispersant characteristics and good thermal and oxidative resistance should be used for trunk piston diesel engines that run at medium speeds and use residual heavy oil for fuel.

c) Only highly alkaline marine diesel engine oils with very good dispersive and neutralizing properties should be used to lubricate cylinders on crosshead engines that also use residual heavy oil for fuel.

METAL DEACTIVATORS/PASSIVATORS

Dialkylzinc dithiophosphates; metal phenates; organic nitrogen and sulphur compounds, amines, benzotriazoles, derivates, certain soaps, etc. The effect is based on the formation of surface films so that metal surfaces cannot induce oil oxidation catalytically.

METAL SOAPS

Metals and their compounds react with fatty acids and form metallic soaps; these are used as EP additives in lubricating oils and as thickening agents in lubricating greases.

METALWORKING OILS

Collective term for cutting oils, rolling oils, drawing oils and drilling oils, both water-miscible and non-water-miscible; standard term is coolant. Their main tasks depend on the application: lubrication, cooling, transportation of swarf, corrosion protection, etc. (See coolants.)

METHANE – CH4

First molecule of the paraffinic (alkane) family of hydrocarbons; main component of natural gas; also, contained in refinery gas, coal gas, etc.

MIL SPECIFICATIONS

Specifications of the US military with minimum requirements for the operating supplies they purchase; some engine and machine manufacturers specify the same minimum requirements,

i.e. in accordance with MIL specifications; compliance with minimum requirements is considered to be a quality standard.

MINERAL OILS

Mineral oils and mineral oil products are liquid distillation and refinery products obtained from petroleum, a mineral-based raw material, and which primarily consist of mixtures of saturated and possibly very small amounts of unsaturated hydrocarbons.

MIXED FRICTION

Is a friction situation where boundary friction and viscous friction occur together/

in sequence. Surface roughness (roughness points) are sometimes separated but sometimes contact is made so that wear occurs.

MOLYBDENUM DISULPHIDE (MOS2)

This is a solid lubricant with a layer lattice structure. If it is properly worked into the metal surface, this solid body with a lamellar structure can reduce the coefficient of friction of the surface for a period of time. It is often use as an additive mixed in with lubricating oils, lubricating greases, compounds, etc.

MOULD OILS

a) Moulds made of wood, metal or similar material for the manufacture of concrete, ceramics, pantiles, etc. are lubricated with thin oils or emulsions for effective release of the moulded parts.
b) Core oils for mixing with moulding sand.

MULTI-GRADE OILS

These are industrial lubricants which use special additives to meet the requirements of various machine tools units. They can therefore be used as gear oils, slide oils, cutting oils, etc.

Multi-Grade Engine and Gear Oils
These are lubricating oils which are intended for use in vehicles all the year round thanks to their very good viscosity temperature characteristics. They cover several SAE classes, for multi-grade engine oils:
5W-30, 10W-30, 5W-40, 15W-50, etc.,
VI approx. 130 to 170.
For multi-grade gear oils: 75W-90, 80W-90, 85W-140, etc.,
VI approx. 115 to 170.

n

NAPHTENE

Outdated term for saturated cyclic hydrocarbons, also called cycloparaffin or cycloalkane, generally 5 or 6 hydrocarbon atoms in the ring (more rarely 7 and 8).

NAPHTHA

This is the designation for a raw gasoline with a boiling range from 30°C to 150°C. The quality of the petroleum varies greatly depending on where it comes from.

NATURAL GAS

Is present in petroleum and in separate reservoirs below the surface of the earth; it is mostly methane.

NEUTRAL OILS

International designation for high-grade refined products, e.g. solvent refined products.

NLGI

National Lubricating Grease Institute.

NLGI CLASSES

Classification of consistency (penetration classes) for lubricating greases: DIN 51 818.

NOACK TEST

It determines the volatility losses of a lubricating oil at high temperatures; evaporating loss of a lubricating oil is equivalent to oil consumption in the engine; this causes the properties of the remaining lubricating oil to change: DIN 51 581, CEC L-40-T-87 – see volatility loss.

NORMAL LUBRICATING OIL

These are pure mineral oils that are to be used for lubricating purposes but which do not place any special requirements on the lubricants. DIN 51 501.

o

OCTANE NUMBER (ON)

This is a dimension value for the anti-knock properties of petrol; it describes the behaviour of fuel during combustion in the engine. For the combustion process to operate normally, it is essential for the fuel to have adequate anti-knock properties - see anti-knock resistance. Reference fuels are: n-heptane with ON = 0 and Iso octane with ON = 100, determined in DIN 51 756 P 1 to P 6.

OIL COAL OR OIL COKE

Hard deposits like coal or coke in cylinders and piston ring grooves of internal combustion engines, etc. Occurs in recirculating oils if the oil has aged, and also as a result of the ingress of contaminants and thermal loading.

OIL SEPARATION

It is possible that small amounts of oil may separate from lubricating greases if it is stored for a long time or if it operates at higher operating temperatures. This is normal and of no significance. However, it is not acceptable for larger amounts of oil to separate out (what is termed bleeding). DIN 51 817 sets out conditions of oil separation under static conditions.

OILS

A distinction is made between the source, manufacture and the chemical structure:

a) Animal and vegetable oils: these are esters or fatty acids
b) Mineral oils, which - depending on their structure - are composed of paraffins (alkanes)
naphthenes (cycloalkanes) or aromats
c) Synthetic oils, such as silicone oils, polyglycols, ester compounds, etc.

OLEORESINS

Organic oxygen and/or sulphur compounds which are found in dissolved form in petroleum products; generally, have strong dyeing effect; oil resins are absorbed in silica gel or bleaching earth.

OMC

Outboard Marine Corporation; manufacturer of spark-ignition engines for 2- and 4-stroke outboard motors, chain saws, etc.; the OMC specifications specifically set out requirements for two-stroke engine oils.

OPEC

Organisation of the Petroleum Exporting Countries.

OXIDATION

Oxidation is a combustion process; oxygen is attached to certain elements or molecules. Thickening, varnishing, polymers, corrosive-acting radicals, etc. occur in the case of hydrocarbons.

OXIDATION INHIBITORS

(Antioxidants – AO) dialkylzinc dithiophosphates; compounds of nitrogen, phosphorus and sulphur (amines, phenoles in combination with zinc, tin, barium, calcium, etc.). They prevent or control the oxidation of oil and the formation of sludge, varnishing and corrosive compounds. They thus limit or retard the increase in viscosity of the lubricating oil.

p

PARAFFIN OILS

Outdated designation for paraffin liquid, white oils and light mineral oils – see white oil, vaseline.

PARAFFIN SEPARATION (START OF PARAFFIN SEPARATION)

Start of paraffin separation under specified test conditions for diesel fuels indicated in °C; relevant measuring methods. limit of filterability (CFPP), cloud point (CP).

PARAFFINS (ALKANES)

Gaseous, fluid and solid chain, saturated hydrocarbon compounds; a distinction is made between normal paraffins with a chain structure and iso(i) paraffins with a branched structure.

PARTIAL LUBRICATION

As a result of low sliding speed or excessive pressure, the sliding surfaces are not fully separated; there is both hydrodynamic lubrication and contact between the sliding surfaces (mixed friction) – see friction.

PENETRATION

Is a dimension for consistency (solidity or fluidity) of a substance. In the case of lubricating greases, it is the amount by which a cone with specified dimensions penetrates vertically into the specimen to be examined under specified conditions. DIN ISO 2137, DIN 51 804 P 2 – see consistency, unworked penetration and worked penetration.

PENETROMETER

Device to determine penetration.

PEROXIDE

Undesirable chemical compounds, organic and inorganic, which favour the formation of resins through oxidation and polymerisation.

PETROL

Consists of a chain and cyclic hydrocarbon mixture with a boiling range of approx. 30 to 215°C to operate petrol engines; leaded petrol: DIN 51 600; unleaded petrol: DIN 51 607, EN 228 - also see benzin.

PETROLEUM

In porous rocks below the surface of the earth, hydrocarbon mixtures made of animal and vegetable greases produced by temperature, pressure and catalytic mechanisms of action, contains negligible amounts of oxygen, sulphur, nitrogen and metals; a distinction is made between paraffin-base, naphthene-base and mix-base petroleum oils.

PETROLEUM (KEROSENE)

Hydrocarbon fraction from petroleum, the boiling range is between 130 and 280°C, hazard class A II or A III depending on the fraction. Used as oil for illumination, burning or as a solvent, also called kerosene: DIN 51 636.

PH VALUE

Dimension for hydrogen (H) ionic concentration in an aqueous solution for an acidic and alkaline reaction: pH value = 7: neutral; pH > 7: alkaline; pH < 7: acidic. Important for checking coolants mixed with water. pH paper or electric measuring devices are used for measurement. DIN 51 369.

PIPELINE

Pipeline through which petroleum, crude oil, mineral oil products and other liquid media or gases are transported.

PITTINGS

Small cavities that appear on the surface of gear teeth as a result of material fatigue; in the rolling circle area, small cracks form, which later develop into small recesses and holes in the surface.

PLANKTON

From the Greek for "wandering thing"; all animal and plant microorganisms freely suspended in water, which are the main constituents of sapropel and later lead to the formation of reserves of petroleum.

PLATFORMING

Catalytic reforming of straight-run benzin using catalytic converters containing platinum.

POISE

A unit of dynamic viscosity; can be calculated from the measured cinematic viscosity (Stokes) by multiplication with the density of the fluid to be tested at a certain test temperature (see viscosity).

POLYALPHAOLEFINS (PAO)

These are synthetic hydrocarbons (especially Iso paraffins with short main and long side chains), which are produced from paraffin slack wax by means of hydro cracking processes using a certain catalytic technology (polymerisation and copolymerisation of low olefins).

POLYMERISATION

Combination of unsaturated hydrocarbon molecules to form a large molecule (thickening) in the presence of catalysts and heat (manufacturing process for synthetic lubricating oils).

POUR POINT

Is the temperature at which cooling oil just stops flowing under specified conditions. The pour point only provides limited information on the low-temperature flow characteristics of an oil in a certain machine. To determine the pour point: DIN ISO 3016

POUR POINT IMPROVER

Active ingredients which, when mineral oils (primarily paraffin-based oils) cool down, initially prevent the clumping of the paraffin crystals that are forming and thus improve fluidity when cold.

POUR POINT MODIFIER

Polymethacrylates, alkyl-phenoles, naphthalene with chlorinated paraffins, propylene copolymers, etc. The effect is based on preventing the paraffin crystals from clumping together or becoming waxy, thus giving better fluidity. The oil only solidifies at lower temperatures – also see pour point modifiers.

PPM

Unit of measure: parts per million.

PREMIUM OIL

Engine oil with active ingredients (oxidation and corrosion inhibitors).

PRESERVATIVE AGENT

Imidazoles, amidoacetate, etc. During use coolants mixed with water (e.g. oil-in-water emulsions) can provide good nutrients for fungus, yeasts and bacteria, which cause various problems (corrosion, odour, etc.). The purpose of preservative agents is to prevent the relevant germs from spreading. It is important to check the number of germs on a regular basis.

PRESERVATIVE OILS

These are used to preserve wood, e.g. to impregnate railroad sleepers and to soak porous materials such as insulating materials, paper and leather.

PROPANE

Gaseous hydrocarbons at normal temperature C3H8: DIN 51 622.

PUNCHING OILS

Metal-processing oil for protecting tools and workpieces when punching metal or to make compounds that need to be shaped such as porcelain, etc. supple.

PYCNOMETER

A container whose volume is precisely known to determine density p: DIN 51 757.

r

RAFFINATE

Distillate enhanced by chemical and/or physical procedures.

RAMSBOTTOM TEST

Carbonisation test for lubricating oils: DIN ISO 4262; EN 8.

RECLAIMED OIL

Reclaimed used oil is the product of reprocessed used oils. This involves centrifugal processing and filtering of sludge, water and mechanical contaminants. MOTOREX never uses reclaimed oils.

REDWOOD SECONDS (R”)

A conventional measure for viscosity commonly used in England, Redwood viscometer.

REFINING

Hydrocarbons still contain compounds with sulphur, oxygen, nitrogen and other contaminants after distillation and vacuum distillation; these are separated from the hydrocarbons during subsequent refining as a result of chemical-physical processes using solvents or acids, thus improving quality considerably.

REFORMING

Conversion of hydrocarbons (benzin) with a low octane number into benzin with a high octane number.
a) Thermal reforming: Long-chain paraffin hydrocarbons are converted into aromatics and olefins.
b) Catalytic reforming: Long-chain paraffin hydrocarbons are converted into isoparaffins and aromatics.

REFRACTION INDEX

Specifies the deflection of a beam of light of a certain wavelength as it passes through a material, e.g. to identify oils. Provides information on the molecular composition.

REFRACTOMETER

Device to determine by visual means (calculate the light beam) the oil content of a water-mixed coolant (emulsion).

REGULAR OIL

Non-compounded lubricating oil, in some cases high-quality refined products but without active

ingredients (additives).

RESIDUAL OILS

In the context of distilling or cracking, the liquid parts that have not evaporated, axle oil, bright stocks, etc

RESIN FORMATION

Ageing of mineral oil products through the formation of highly polymerised condensation products.

RING STICKING

Sticking and formation of residues in piston ring groves; piston rings stick.

ROLLER-CONTACT BEARING GREASES

Lubrication for roller-contact bearings, generally lubricating grease containing lithium soap or, in some cases, sodium soap lubricating grease as well. Calcium soap lubricating grease is suitable for use when subject to exposure to considerable amounts of water.

RON

Research Octane Number = Dimension value for the anti-knock properties of petrol, e.g. 95, 98 or 100 RON.

ROPE GREASE

Grease to preserve rope made of all kinds of natural fibres and keep it supple. Rope grease is often rapidly biodegradable.

RUST

Corrosion produced by the simultaneous effect of oxygen and moisture on the surface of iron or steel (hydrated ferric oxide).

RUST-INHIBITING OIL

See corrosion-protecting oils and greases.

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SAE

Society of Automotive Engineers. International society of over 83,000 engineers from 97 countries, which exchange know-how in the fields of automotive engineering, aerospace, engines, commercial vehicles, production, fuels and materials.
More at www.sae.org/about/

SELECTIVE SOLVENT REFINING

Refining using solvents (duo-sol, Edeleanu, furfurol processes, etc.); undesirable hydrocarbon compounds are released from the individual hydrocarbon types and separated.

SELF-IGNITION POINT

Is the temperature at which a flammable substance will ignite without external ignition, depending on the conditions (temperature, pressure, etc.) and the oxygen content of the surrounding air.

SEWING MACHINE OILS

Very thin-bodied technical white oil, 7 to 12 mm2/s at 40°C, often contains solid additives.

SHEAR STABILITY

Viscosity index improvers (polymers soluble in oil) are added to lubricating oils, hydraulic oils, etc. to improve the viscosity-temperature characteristics. Some of these polymer molecules, which have linear, lattice or net structures, have a huge molecular structure in the high-temperature range (macro molecules) and then change or break their molecular structure when exposed to shear forces, as occur in gears or hydraulic systems. Here there is a loss of viscosity to a greater or lesser extent.

SILICONE

Silicone oxide compounds, which exist in forms that range from viscous to solid. The various viscous silicones are generally colourless oils with very good viscosity temperature properties. They are used as additives, synthetic oils, hydraulic oils, insulating agents, etc. in the mineral oil industry. Solid silcones are very resistant to temperature.

SLUDGE FORMATION

Ageing of mineral oils. The influence of air and water may cause mineral products to form oxidation substances and polymerisation may occur; if this problem is pronounced, these oxidation products are no longer dispersed in oil so they solidify and form sludge.

SODIUM COMPLEX SOAP LUBRICATING GREASE

Has good lubricating characteristics, with good adhesion and especially low oil separation, thus making it particularly suitable for fast-running bearings. It is, however, very sensitive to water.

SODIUM LUBRICATING GREASE

Lubricating grease made of sodium soap and mineral oils; can be used up to operating temperatures of 120°C. Sodium lubricating greases are emulsfiable and must not be used at wet lubricating points. They are very suitable for lubricating gears and as fluid gear greases in NLGI classes 0,00,000.

SOLID LUBRICANTS

Is generally only used and required for lubricating tasks under extreme conditions (e.g. for operation in mixed friction areas). The best known are graphite, molybdenum disulphide and plastics such as polytetrafluoroethylene, etc. These are applied directly in powder form, in suspensions, pastes, metallic films, paints and plastics.

SOLVATES

Solvent-neutral oils, solvent raffinates, mineral oils refined with solvents.

SOOT

Pure amorphous carbon, which is produced by incomplete combustion of fuels containing carbon.shear stability: DIN 51 382; CEC L-14-A-88; L-25-A-78; L-37-T-85; L-45-T-92.

SPARK-EROSION OILS

Are used as dielectric materials during spark-erosion machine operations on what are generally very hard metals. They must provide good insulation, cool the tool and workpiece and they should be readily ionisable. Some of the points that good products feature, are: very little volatility, high flash point, oxidation stability, non-aggressive to the skin and seals, chemically neutral, highly refined, low in aromatics. Viscosity is approx. 2 to 4.5 mm2/s at 40°C.

SPECIFICATION

Specifications for lubricants and fuels in which physical characteristics, chemical characteristics and test methods are specified.

SPECTROSCOPY

Radiation energies of various wavelengths, e.g. infrared rays, cause hydrocarbon molecules to reflect radiation which varies according to the molecule and thus allow the structure of the molecule or additives or metal abrasives to be identified.

SPINDLE OILS

Thin-bodied lubricating oil for lubricating spindles in textile machines; viscosity around 10 to 80 mm2/s at 20°C. Also, lubricants to lubricate and cool electrically powered spindles in machine tools, etc.

SPRING GREASES

Lubricating greases to lubricate leaf springs, generally containing MoS2 or graphite.

STABILISERS

Active ingredients, inhibitors which protect the medium from ageing.

STICK-SLIP ADDITIVES

Additives (friction-modifying active ingredients) added to gear oils and other lubricants in order to prevent stick-slip effects – e.g. for slideways on machine tools – at very low speeds.

1 St (Stokes) = 1 cm2/s = 100 cSt = 100 mm2/s

STOKES

Unit to measure cinematic viscosity.

SUPER TRACTOR OIL UNIVERSAL - STOU

Hydraulic oil for engines and gearboxes for universal application in as many engines, machines, devices and units as possible, in particular with wet brakes and clutches in agriculture and the construction industry. To streamline types and prevent different lubricants from mixing when different items of equipment are connected together.

SYNTHETIC LUBRICANTS

These lubricants are developed for special technical applications and special requirements. Nowadays they are specified for high-performance engines and aggregates and also for special purposes, for instance requirements such as fire resistance, high-temperature stability, low-temperature performance, resistance to radioactive radiation, volatility loss, resistance to oxidation (complying with service life), high-pressure stability, viscosity temperature characteristics, etc.

The response of additives for the various synthetic lubricants is very different and results in the development of new additive combinations, which in some cases can only be used for certain synthetic lubricants. The following synthetic lubricants are used: Polyalkylene glycols, synthetic hydrocarbons (e.g. polyalphaolefins, dialkylbenzole, polyisobutylene), dicarbon acid and polyalcohol ester, phosphoric acid ester, silicone, polyphenyl ether, fluorocarbons, etc.

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TACKY LUBRICATING OILS

Lubricating oils with adhesion improvers, tacky viscous, often bituminous, highly viscous lubricants, which are also diluted before use.

THINNING OF LUBRICATING OIL

This occurs in spark-ignition engines if, when the engine is cold, fuel condenses on the cylinder and is then mixed with the lubricating oil through the pumping action at the piston rings. The same phenomenon may occur with fuels with a high final boiling point. When benzin thins lubricating oil in the engine oil, viscosity is reduced and thus jeopardizes lubrication. Testing in accordance with DIN: 51 565.

THREAD-CUTTING OILS

Non-water-miscible lubricants (metalworking oils) for cutting metal operations. The task of these oils is to lubricate, dissipate heat and remove swarf.

TIMKEN TEST/MACHINE

Grease testing machine to determine the high-pressure characteristics of lubricating oils (wear tester). A square test plate is pressed against a moving shaft with the anti-friction bearing ring fitted; to ascertain the loading and appearance of the test specimen.

TRIBOLOGY/TRIBO TECHNOLOGY

Tribology covers scientific research and technical applications of friction, wear and lubrication, taking account of design, materials science, regulations imposed by the authorities, etc. Tribo technology also deals with the retention of the value of machines and tools, simplification of lubrication application, minimisation of energy losses plus environmental demands, cost-optimised production and targeted maintenance schedules.

TWO-STROKE ENGINE OILS

When lubricating two-stroke spark-ignition engines, a distinction is made between the following two-stroke engine oils according to the engine type, use, lubrication system, miscibility, mixing ratio, corrosion protection, cleaning effect, biological degradability, etc.:

a) Self-mixing (pre-diluted)
b) Not self-mixing (not pre-diluted) for automatic fresh oil (fresh oil lubrication)
c) Outboard motor oils

The two-stroke oils are classified into three API service categories (American Petroleum Institute): TA, TB, TC for mopeds, scooters, motorcycles and agricultural equipment. There are also the JASO specifications (Japan Automobile Standards Organisation) FA, FB and FC for engine oils with a low sulphate ash content for air-cooled two-stroke engines.

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UNSATURATED COMPOUNDS

Hydrocarbons with unsaturated double bonds (triple bonds) of carbon atoms. The unsaturated compounds are very reactive.

UNWORKED PENETRATION

When measuring the penetration of a sample of lubricating grease at 25°C which has not been pre-treated in the internal mixer - also see penetration, worked penetration.

USED OILS

Used lubricating oils which are not suitable for use again as lubricating oil on account of ageing and contamination.

v

VACUUM DISTILLATION

This type of distillation is used for the manufacture of lubricating oils, because distillation at normal pressure (atmospheric distillation) would break (crack) the larger hydrocarbon molecules – see distillat

VASELINE

Natural or artificial mixtures of solid and liquid hydrocarbons made of petroleum, free of odour and taste. Natural vaseline is made of petrolatum by means of refining.

VISCOGRAM

Sheet for measuring and recording the viscosity obtained for mixtures.

VISCOMETER

Device for determining the viscosity of fluids. A distinction is made between: capillary, rotation, falling-ball and efflux viscometers.

VISCOSITY

Viscosity is the characteristic of a fluid to offer resistance to the interacting laminar movement (deformation) of two adjacent layers (internal friction, shear stress): DIN 1342, DIN 51 550, DIN ISO 3104.

Viscosity classes
See SAE classes and ISO viscosity classification.

VISCOSITY INDEX (VI)

It is a calculated figure on a conventional scale which describes how the viscosity of a mineral oil or synthetic oil product changes with the temperature. A higher viscosity index indicates a smaller change in viscosity with temperature than a lower viscosity index. Calculation of the VI from the cinematic viscosity: DIN ISO 2909, ASTM D 2270.

VISCOSITY INDEX IMPROVER

Active ingredients (viscosity improver, polymers), which - when dissolved in the mineral oil - improves the viscosity temperature characteristics, i.e. they reduce the temperature dependency of viscosity; at low temperatures, they improve the flow properties and at high temperatures they achieve a higher viscosity than would be the case without VI improvers. VI improvers are important constituents of multi-grade lubricating oils. The most important viscosity index improver groups are: Polymethacrylates (PMA), olefin copolymers (OCP), polyisobuthylene (PIB) and styrene-butadiene copolymers (SCB) or styrene-isoprene copolymers (SIC).

VISCOSITY TEMPERATURE CHARACTERISTICS (VT)

The VT of a fluid is how the viscosity alters as a function of the change in temperature – see viscosity index.

VISCOUS FRICTION

Exists when rubbing surfaces on top of each other are completely separated by a lubricant so that there is no direct contact. No wear occurs. The viscosity, temperature, shear rate and the pressure properties of the lubricant determine the viscous friction.

VOLATILITY LOSS (NOACK)

Volatility loss of lubricating oil at higher temperatures (up to 350°C); it is particularly important for engine and cylinder lubrication. At the high temperatures that occur, a high volatility loss may be equivalent to a higher oil consumption and may lead to a change in the characteristics of the oil: DIN 51 581 (Noack Test).

w

WASHING PETROLEUM

Previously a cleaning fluid for machine components – is today superseded by modern VOC-free or low-VOC cleaning agents.

WATER HAZARD CLASSES (WGK)

There are three categories of substances that are a hazard to water. These are classified in the following classes according to their physical, chemical and biological characteristics in line with the hazard they represent:
WGK 3: Highly hazardous to water
WGK 2: Hazardous to water
WGK 1: Slightly hazardous to water

WATER RESISTANCE

There is a static and dynamic test to examine the performance of lubricating greases when exposed to water. The influence of water on lubricating grease when exposed to various temperatures is examined. DIN 51 807 P1/P2.

WATER-MISCIBLE COOLANTS

Water-soluble coolant, water-mixed coolant and coolant emulsions (oil in water) for cooling and lubricating when working materials – see coolant.

WEAR

Wear, abrasion, etc.

WHITE OILS

Highly refined mineral oils that are as clear as water or slightly yellow. A distinction is made between technical and medical white oils.

WHITE SPIRIT

High-boiling special benzin, with a boiling range >55°C.

WIRE ROPE LUBRICANTS

Lubricating greases and special lubricants for lubricating and preserving wire ropes; generally pre-diluted for better wetting.

WOOL FAT

Wax obtained when cleaning sheep's fleeces before processing. Is used as an additive to anti-corrosion oils and greases – see lanolin.

WORKED PENETRATION

The worked penetration is used to identify the consistency of lubricating grease and allows the suitability of the lubricating grease for certain applications to be assessed. Test method: Cone penetration into a sample of lubricating grease that has previously been worked. DIN 51804 P 2.

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