Absolute (or Dynamic) Viscosity
A measure of resistance to flow of a
fluid. The ratio of applied shear stress to rate of shear. The units of
Dynamic viscosity are milli Pascal-seconds in the ISO system and centipoise
Same definition now listed for
'Neutralization Number". The weight, in milligrams of potassium hydroxide
needed to neutralize acids in one gram of oil by ASTM method D 664 or D 974.
The acid number of an oil is a measure of the presence of reactive additives
or oil oxidation.
A refining process in which
unfinished petroleum products, such as gasoline, kerosene, and lubricating
oil stocks are contacted with sulfuric acid to improve their color, odor,
and other properties.
The amount of free acid in any
An agent used for imparting new, or
for improving existing characteristics of a lubricating oil or grease.
The total percentage of all
additives in an oil.
Abbreviation for American Gear
The incorporation of air in the
form of bubbles as a dispersed phase in the bulk liquid. Air may be
entrained in a liquid through mechanical means and/or by release of
dissolved air due to a sudden change in environment. The presence of
entrained air is usually readily apparent from the appearance of the liquid
(ex: bubbly, opaque, etc.) while dissolved air can only be determined by
The minimum temperature for
complete miscibility of equal volumes of aniline and the sample under test.
ASTM Method D 611 describes procedures for determining aniline point and
mixedaniline point of petroleum products and hydrocarbon solvents. Aniline
point is often specified for spray oils, cleaning solvents, and thinners,
where effectiveness depends upon aromatic content. In conjunction with API
gravity, the aniline point may be used to calculate the net heat of
combustion of aviation fuels.
An additive used for controlling
A type of bearing employing rollers
or balls. (rolling bearings)
Resistance to detonation or pinging
in spark-ignition engines
A chemical added to gasoline,
lubricating oil, etc., to inhibit oxidation.
American Petroleum Institute
API Engine Service Classification
System Classification and designations for lubricating oils for
automotive engines developed by API in conjunction with SAE and ASTM.
An arbitrary scale expressing the
gravity or density of liquid petroleum products. The measuring scale is
calibrated in terms of degrees API. It may be calculated in terms of the
Deg API =
The percent by weight of residue
left after combustion of a sample of a fuel oil or other petroleum oil; it
is usually determined in the United States by ASTM Method D 482.
American Society of Lubrication
Engineers. Name changed to STLE.
American Society for Testing and
Materials. Develops test methods and product specifications.
Apparatus widely used for
determining the color of lubricating oil; it is described in ASTM Method D
1500. The color so determined is known as ASTM color.
The temperature at which D 87 wax
first shows a minimum rate of temperature change; also known as the English
A method of specifying viscosity
levels for industrial lubricants; does not connote quality, D 2422
A state of lubrication existing
when conditions of bearings, design, feed, load, and method of application
of the lubricant do not permit the formation of a separating lubricant film
by hydrodynamic action. Under these conditions, absorption of the lubricant
or of some of the active components of the lubricant upon the bearing
surface, or the formation of low shear-strength chemical compounds by the
reaction of the components of the lubricant with the bearing surfaces,
reduces the metallic contact and determines the character of the frictional
Refined, high-viscosity lubricating
oils usually made from residual stocks by suitable treatment, such as a
combination of acid treatment or solvent extraction with dewaxing or clay
British Thermal Unit (BTU)
The quantity of heat required to
raise, by 1°F, the temperature of one pound of water at its maximum density
The metric units of Dynamic
viscosity, numerically identical to the ISO units of milli Pascal seconds. 1
cP = 1 mPa•s
The metric units of Kinematic
viscosity, numerically identical to the ISO units of millimeter squared per
second. 1 cSt = 1 mm2/s
Cetane Number (Calculated)
The cetane number of distillate
fuels as estimated from the API gravity and mid-boiling point by using a
formula given in Appendix II of ASTM Method D 975. This estimate is used if
a standard test engine is not available, or if the sample is too small for
an engine test.
Code of Federal Regulations.
1. The phenomenon observed among
gear lubricants and greases when they thicken, due to cold weather or other
causes, to such an extent that a groove is formed through which the part to
be lubricated moves without actually coming in full contact with the
2. A term used in percolation
filtration; may be defined as a preponderance of flow through certain
portions of the clay bed.
Cleveland Open-Cup (COC) Tester
Apparatus used for the
determination of flash and fire points of all petroleum products flashing
above 175°F, with the exception of fuel oils.
With respect to a petroleum oil,
the temperature at which paraffin wax or other solid substances begin to
crystallize or separate from the solution, imparting a cloudy appearance to
the oil when the oil is chilled under prescribed conditions. These
conditions are described in ASTM Method D 97.
A factor in the identification,
rather than in the quality rating of a petroleum product except where
staining or appearance are considerations.
Copper Strip Corrosion
A test method (D130) which measures
the tendency of a lubricant or fuel to corrode a strip of copper metal under
standard test conditions.
The gradual eating away of metallic
surfaces as the result of oxidation or other chemical action. It is caused
by acids or other corrosive agents.
The mass of a unit of volume of a
A lubricating oil possessing
special sludge-dispersing properties for use in internal combustion engines.
These properties are usually conferred on the oil by the incorporation of
special additives. Detergent oils hold sludge particles in suspension and
thus promote engine cleanliness.
A measure of the adequacy of
insulating materials for the electrical stresses they are intended to
resist. Testing of electrical insulating oils of petroleum origin for use in
cable, transformer, oil circuit breakers, and similar apparatus is usually
done in the United States by ASTM Method D 877.
A synthetic lubricating fluid made
from esters; also called ester oil.
A dispersing agent, compatible with
a carrier fluid, which holds a very finely divided third substance in a
dispersed state in the carrier fluid.
In general, the dropping point is
the temperature at which the grease passes from a semisolid to a liquid
state. This change in state is typical of greases containing, thickeners,
and conventional type soaps. Greases containing, as thickeners, materials
other than conventional soaps may, without change in state, separate oil.
The method is useful in identifying the grease as to its type and for
establishing and maintaining benchmarks for quality control.
Solid material left between two
moving surfaces to prevent metal-to-metal contact, thus reducing wear. Such
materials are useful in the region of boundary lubrication, and for
lubrication under conditions of extreme high or low temperatures where
normal lubricants are inadequate. Some examples are graphite, molybdenum
disulfide, boron nitride, and certain plastics such as tetrafluorthylene
A substance used to promote or aid
the emulsification of two liquids and to enhance the stability of the
An extreme pressure additive
introduced into a lubricant to impart load-carrying or anti-weld qualities.
Extreme pressure lubricant: any of
the lubricating oils or greases which contain a substance or substances
specifically introduced to prevent metal-to-metal contact in the operation
of highly loaded gears. In some cases, this is accomplished by the substance
reacting with the metal to form a protective film.
An animal or vegetable oil which
will combine with an alkali to break down fat to form a soap.
Food & Drug Administration
Any substance, such as talc, mica,
or various powders, which may be added to a grease to make it heavier in
weight or consistency, but which serves no useful function in making the
grease a better lubricant.
The property of an oil which
enables it to maintain an unbroken film on lubricated surfaces under
operating conditions, where otherwise there would be scuffing or scoring of
The lowest temperature at which,
under specified conditions in standardized apparatus, a petroleum product
forms an air vapor mixture which burns continuously when ignited by a small
The lowest temperature at which
vapors arising from the oil will ignite momentarily (i.e., flash) on
application of a flame.
The temperature at which wax or
solids begin to form.
A froth produced by whipping air
into a lubricant.
Equipment used to evaluate a
lubricant's anti-wear qualities, frictional characteristics, or load
carrying capabilities. It derives its name from the four 1/2 inch steel
balls used as test specimens. Three of the balls are held together in a cup
filled with lubricant while the fourth ball is rotated against them.
A process of mechanical attrition
combined with chemical reaction taking place at the common boundary of
loaded contact surfaces having small oscillatory relative motion.
A German gear test for evaluating
anti-wear and EP properties.
General Agreement on Tariffs and
A lubricant composed of a
lubricating fluid, thickened with soap or other material to a solid or
A crystalline form of carbon either
natural or synthetic in origin.
A medium used for the transfer of
heat at temperature levels above that of steam.
Herschel Demulsibility Number
A number which indicates the
ability of anoil to separate from water under conditions specified by the
Herschel Demulsibility Test.
The chemical addition of hydrogen
to a material. In nondestructive hydrogenation, hydrogen is added to a
molecule only if, and where, unsaturation with respect to hydrogen exists.
In destructive hydrogenation, the operation is carried out under conditions
which result in rupture of some of the hydrocarbon chains (cracking);
hydrogen is added where the chain breaks have occurred.
Gears in which the pinion axis
intersects the plane of the ring gear at a point below the ring gear axle
and above the outer edge of the ring gear, or above the ring gear axle and
below the outer edge of the ring gear.
A substance, the presence of which,
in small amounts, in a petroleum product prevents or retards undesirable
chemical changes from taking place in the product, or in the condition of
the equipment in which the product is used. In general, the essential
function of inhibitors is to prevent or retard oxidation or corrosion.
Initial Boiling Point
According to ASTM Method D 86, the
recorded temperature when the first drop of liquid falls from the end of the
An oil used in circuit breakers,
switches, transformers, and other electrical apparatus for insulating,
cooling, or both. In general, such oils are well-refined petroleum
distillates of low volatility, with high resistance to oxidation and
A measure of resistance to flow of
a fluid under gravity. The ratio of the absolute viscosity to the density at
the temperature of the viscosity measurement. The kinematic viscosity of
lubricating oils is commonly measured using ASTM Method D 445. The units are
millimeters squared per second in the ISO system, centistokes in metric and
Saybolt Universal Seconds in (obsolescent) U.S. practice.
A term originally used to denote
that which is "fit" and "proper". Most often, it is used to describe foods
that are permitted to be eaten by Jewish dietary laws.
A status of Kosher food which is
compatible with all other types of Kosher food, whether dairy or meat, when
it is prepared on neutral equipment.
An animal oil prepared from the fat
of swine. These oils are compounded with mineral oils to yield lubricants of
special wetting properties, especially cutting oils.
A lead soap of naphthenate acid,
which is soluble in mineral lubricants and imparts to them high film
Liquefied Natural Gas (LNG)
Similar to LPG but consisting of
lighter hydrocarbons, such as methane and ethane.
Liquefied Petroleum Gas (LPG)
Light hydrocarbon material, gaseous
at atmospheric temperature and pressure, held in the liquid state by
pressure to facilitate storage, transport, and handling. Commercial
liquefied gas consists essentially of propane, butane, or mixtures thereof.
The primary standard of capacity in
the metric system, equal to the volume of one kilogram of pure water at
maximum density, at approximately 4°C, and under normal atmospheric
Military specification; a guide in
determining the quality requirements of products used by the military
services, published by the United States Department of Defense.
One of the multi-viscosity number
oils in which one oil combines several SAE viscosity number grades.
A lubricating grease suitable to
meet the individual requirements for chassis lubricant, bearing lubricant,
joint lubricant, water-pump lubricant, and cup grease.
One of a group of cyclic
hydrocarbons, also termed cycloparaffins or cycloalkanes. Polycyclic members
are also found in the higher boiling fractions.
An obsolete term for acid number.
The weight, in milligrams, of potassium hydroxide needed to neutralize the
acid in 1 g of oil.
Light overhead cuts of lubricant
stocks. Neutral oils are the basis for most commonly used automotive
National Lubricating Grease
Institute. Primary technical society concerned with grease products.
One of a series of numbers
classifying the consistency range of lubricating greases, based on the ASTM
cone penetration number. The National Lubricating Grease Institute grades
are in order of increasing consistency (hardness). See Appendix D.
- That characteristic of a liquid
which is responsible for the degree of friction between two surfaces which
cannot be accounted for on the basis of viscosity alone.
- The ability of a
lubricating oil to orient itself on bearing surfaces so as to form new
surfaces with a low coefficient of static friction. 3. That characteristic
which an oil must possess to a sufficient degree to enable it to overcome
every frictional stress to which it is subjected.
A petroleum lubricating or process
oil refined until its color, by transmitted light, is straw to pale yellow.
Consistency, expressed as the
distance in millimeters that a standard needle or cone penetrates vertically
into a sample of the material under known conditions of loading, time, and
A lubricating oil additive which
lowers the pour point of an oil containing wax by reducing the tendency of
the wax to form a solid mass in the oil. Also called pour-point depressor,
The lowest temperature at which oil
will pour or flow when it is chilled without disturbance under definite
conditions. (ASTM Method D 97).
The ability of a
pour-depressant-treated oil to maintain its original ASTM pour point when
subjected to storage at low temperatures approximating winter conditions.
An oil not used for lubrication but
as a component of another material, or as a carrier of other products.
Rust and oxidation inhibited.
Society of Automotive Engineers.
Saybolt Universal Viscosity
The time, in seconds, for 60 mi of
fluid to flow through a capillary tube in a Saybolt Universal viscometer at
a given temperature using ASTM Method D 88.
Extreme pressure agents (sulfur,
chlorine) employed in certain types of automotive gear lubricants.
The ratio of the weight (in air) of
a given volume of a material to the weight (in air) of an equal volume of
water at stated temperature.
Society of Tribologists and
Lubrication Engineers (formerly ASLE). Primary technical society for
Saybolt Universal Seconds...the
obsolescent U.S. units for kinematic viscosity, still commonly reported for
some lubricants. SUS units are the time in seconds for 60 ml of fluid to
flow through a capillary in a Saybolt viscosimeter. For many lubricants, the
SUS viscosity is approximately five times the kinematic viscosity in
Defined in ASTM Method D 874 as the
ash which remains after a sample of new additive-containing lubricating oil
has been carbonized, and the residue subsequently heated with sulfuric acid
to constant weight.
A product formed from mineral oil
combined with sulfur or certain sulfur compounds. It has far greater film
strength and load-carrying ability than straight mineral oil and is used as
Oils produced by synthesis rather
than by extraction or refinement.
TAN (Total Acid Number)
The quality of base, expressed in
terms of the equivalent number of milligrams of potassium hydroxide, that is
required to titrat the strong base constituents present in 1 g of
sample.(SATM Method D 664 or D 974)
Timken EP Test
The Timken Extreme Pressure Test is
one of many laboratory machines used in determining the load carrying
capacities of oils and greases. In this test, a Timken bearing cup is
rotated against a steel block. The highest load under which a lubricant
prevents scoring of the steel block by the rotating cup is the reported
United States Department of
H-1 applications where incidental
food contact may occur.
H-2 applications where there is no
possibility of food contact.
3-H applications as a release agent
(direct food contact).
VI (Viscosity Index)
Viscosity index...an arbitrary
scale used to show the rate of change of viscosity with temperature, defined
by ASTM Method D 2270. Paraffinic mineral oils have a VI near 100; highly
naphthenic oils have a VI near 0.
The measure of internal friction or
resistance to flow of a liquid.
The penetration of a sample of
lubricating grease immediately after it has been brought to 77°F and then
subjected to 60 stokes in a standard grease worker. This procedure and the
standard grease worker are described in ASTM Method D 217.