ASTM D128-98
(Test Method)Standard Test Methods for Analysis of Lubricating Grease
Standard Test Methods for Analysis of Lubricating Grease
SCOPE
1.1 These test methods for analysis cover greases of the conventional type which consist essentially of petroleum oil and soap. The constituents which can be determined are soap, unsaponifiable matter (petroleum oil, etc.), water, free alkalinity, free fatty acid, fat, glycerin, and insolubles. Note 1-Any of the test methods described herein are best used by an experienced grease analyst who may also be able to make appropriate adaptations of the techniques as occasion requires.
1.2 A supplementary test method is provided in the Appendix. This test method is intended primarily for application to greases containing thickeners which are essentially insoluble in -hexane, and to greases which cannot be analyzed by conventional methods because of the presence of such constituents as nonpetroleum fluids or nonsoap-type thickeners, or both. In some cases, these constituents can react with strong acid or alkaline solutions.
1.3 These test methods appear in the following order: Sections Ash Determination 7 to 11 Insolubles, Soap, Fat, Petroleum Oil, 12 to 20 and Unisponifiable Matter Free Alkali and Free Acid 21 to 23 Water 24 Glycerin (Quantitative) 25 to 29
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices, and determine the applicability of regulatory limitations prior to use. For hazard statements, see Notes 3 through 22.
1.5 The values stated in SI units are to be considered the standard.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
An American National Standard
Designation: D 128 – 98
Standard Test Methods for
Analysis of Lubricating Grease
This standard is issued under the fixed designation D 128; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope D 95 Test Method for Water in Petroleum Products and
Bituminous Materials by Distillation
1.1 These test methods for analysis cover greases of the
D 156 Test Method for Saybolt Color of Petroleum Prod-
conventional type, which consist essentially of petroleum oil
ucts (Saybolt Chromometer Method)
and soap. The constituents that can be determined are soap,
D 217 Test Methods for Cone Penetration of Lubricating
unsaponifiable matter (petroleum oil, and so forth), water, free
Grease
alkalinity, free fatty acid, fat, glycerin, and insolubles.
D 445 Test Method for Kinematic Viscosity of Transparent
NOTE 1—Any of the test methods described herein are best used by an
and Opaque Liquids (and the Calculation of Dynamic
experienced grease analyst who may also be able to make appropriate
Viscosity)
adaptations of the techniques as occasion requires.
D 473 Test Method for Sediment in Crude Oils and Fuel
1.2 A supplementary test method is provided in Appendix 2
Oils by the Extraction Method
X1. This test method is intended primarily for application to
D 1078 Test Method for Distillation Range of Volatile
greases containing thickeners that are essentially insoluble in 3
Organic Liquids
n-hexane, and to greases that cannot be analyzed by conven-
D 1193 Specification for Reagent Water
tional methods because of the presence of such constituents as
D 1353 Test Method for Nonvolatile Matter in Volatile
nonpetroleum fluids or nonsoap-type thickeners, or both. In
Solvents for Use in Paint, Varnish, Lacquer, and Related
some cases, these constituents can react with strong acid or
Products
alkaline solutions.
1.3 These test methods appear in the following order: 3. Terminology
Sections
3.1 Definitions:
Ash Determination 7-11
3.1.1 asphalt, n—a dark brown-to-black cementitious ma-
Insolubles, Soap, Fat, Petroleum Oil, 12-20
terial in which the predominating constituents are bitumens.
and Unsaponifiable Matter
Free Alkali and Free Acid 21-23
3.1.1.1 Discussion—Asphalt can be a natural product or a
Water 24
material obtained from petroleum processing.
Glycerin (Quantitative) 25-29
3.1.2 candle pitch, n—a dark brown-to-black, tarry or solid,
1.4 This standard does not purport to address all of the
by-product residue from soap and candle stock manufacture,
safety concerns, if any, associated with its use. It is the
refining of vegetable oils, refining of wool grease, or refining of
responsibility of the user of this standard to establish appro-
refuse animal fats.
priate safety and health practices, and determine the applica-
3.1.3 cup grease, n—any lubricating grease having physical
bility of regulatory limitations prior to use. For hazard state-
properties, such as consistency and texture, suitable for its use
ments, see Notes 3-22.
in spring-loaded or screw-type lubricating cups.
1.5 The values stated in SI units are to be considered the
3.1.3.1 Discussion—Cup greases are predominantly NLGI
standard.
No. 3 or 4 calcium greases, but grease types other than calcium
are also used.
2. Referenced Documents
2.1 ASTM Standards:
These test methods are under the jurisdiction of ASTM Committee D-2 on
Petroleum Products and Lubricants and are the direct responsibility of Subcommit-
tee D02.G 0.01 on Chemical and General Laboratory Tests. Annual Book of ASTM Standards, Vol 05.01.
Current edition approved Nov. 10, 1998. Published January 1999. Originally Annual Book of ASTM Standards, Vol 06.04.
published as D 128 – 22. Last previous edition D 128 – 94a. Annual Book of ASTM Standards, Vol 11.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D128–98
3.1.4 degras (wool fat, wool grease, wool wax), n—a 3.1.14 non-soap thickener (synthetic thickener, inorganic
fat-like material comprised primarily of sterols, other higher thickener, organic thickener), n—in lubricating grease, any of
alcohols, and fatty acids, obtained from the solvent extraction several specially treated or synthetic materials, excepting
of sheep’s wool. metallic soaps, that can be thermally or mechanically dispersed
3.1.5 free alkali, n—in lubricating grease, unreacted basic in liquid lubricants to form the lubricating grease structure.
(alkaline) material present in the product. —NLGI Lubricating Grease Guide
3.1.5.1 Discussion—Many greases are made with a slight
3.1.15 residuum, n—a liquid or semi-liquid product ob-
excess of alkali to ensure complete saponification. Free alkali
tained as residue from the distillation of petroleum and
is determined by acidification of a solvent-thinned specimen
consisting primarily of asphaltic hydrocarbons.
and back titration with standardized, alcoholic potassium
3.1.15.1 Discussion—Also known as asphaltic oil, asphal-
hydroxide. It is expressed in terms of the predominating alkali
tum oil, liquid asphalt, black oil, petroleum tailings, and
and a mass % of the total grease composition (for example,
residual oil.
mass % lithium hydroxide).
3.1.16 rosin oil, n—a viscous, oily liquid obtained as a
3.1.6 free fatty acid, n—in lubricating grease, unreacted
condensate when the residue (rosin) from turpentine produc-
carboxylic acid(s) present in the product.
tion is subjected to dry, destructuve distillation.
3.1.6.1 Discussion—Some greases are made with a slight
3.1.16.1 Discussion—Also used to describe specially com-
excess of carboxylic acid to ensure a non-alkaline product.
pounded oils having a rosin base.
Free fatty acid is determined by neutralization of a solvent-
3.1.17 saponification, n—the interaction of fats, fatty acids,
thinned specimen with standardized, alcoholic potassium hy-
or esters generally with an alkali to form the metallic salt,
droxide. Regardless of the actual composition of the carboxylic
which is commonly called soap.
acid(s), it is expressed as free oleic acid and as a mass % of the
—NLGI Lubricating Grease Guide
total grease composition.
3.1.17.1 Discussion—Soap thickeners are most often made
3.1.7 insolubles, n—in lubricating greases analysis, the
by in situ saponification in the lubricating grease base oil.
material remaining after the acid hydrolysis, water extraction,
However, the use of pre-formed soaps is also common;
and solvent extraction of soap-thickened greases.
dispersion is effected by mechanical means and usually with
3.1.7.1 Discussion—Consisting of such products as graph-
heat.
ite, molybdenum disulfide, insoluble polymers, and so forth.
3.1.18 single base, adj— in lubricating grease, relating to a
3.1.8 lubricating grease, n—a semi-fluid to solid product of
thickener comprised of soaps of only one metal.
a dispersion of a thickener in a liquid lubricant.
3.1.8.1 Discussion—The qualifying term, lubricating, 3.1.19 soap, n—in lubricating grease, a product formed in
should always be used. The term, grease, used without the
the saponification (neutralization) of fats, fatty acids, or esters
qualifier refers to a different product, namely certain natural or by inorganic bases.
processed animal fats, such as tallow, lard, and so forth.
3.1.20 Soxhlet apparatus, n—a device, usually of glass,
3.1.9 mixed base, adj—in lubricating grease, the description
used to extract soluble material from a mixture of soluble and
of a thickener system composed of soaps of two metals.
insoluble (generally solid) materials, by passing a volatile
—NLGI Lubricating Grease Guide
solvent through the sample and recirculating the solvent by
3.1.9.1 Discussion—Although mixed-base grease can be
refluxing.
made with soaps of more than two metals, in practice, such is
3.1.21 tar, n—a brown or black, bituminous, liquid or
rarely, if ever, encountered. All of the soaps need not be
semi-solid comprised primarily of bitumens condensed in the
thickeners, although the major soap constituent will be one
processing of coal, petroleum, oil-shale, wood, or other organic
capable of forming a lubricating grease structure. Because the
materials.
mixed soaps are seldom present in equal amounts. The pre-
3.1.22 thickener, n—in lubricating grease, a substance
dominant soap is referred to first.
composed of finely divided solid particles dispersed in a liquid
3.1.10 montan wax, n—a wax-like material comprised pri-
lubricant to form the product’s structure.
marily of montanic acid and its ester, higher aliphatic alcohols,
3.1.22.1 Discussion—The thickener can be fibers (such as
and resins obtained from the solvent extraction of lignite.
various metallic soaps) or plates or spheres (such as certain
3.1.11 neutralization number, n—of petroleum oil, the
non-soap thickeners), which are insoluble or, at most, only very
quantity of acid or base required to titrate to neutrality and
slightly soluble in the liquid lubricant. The general require-
expressed as equivalent milligrams of potassium hydroxide per
ments are that the solid particles be extremely small, uniformly
gram of sample. D 804
dispersed, and capable of forming a relatively stable, gel-like
3.1.12 NLGI, n—National Lubricating Grease Institute
structure with the liquid lubricant. D 217
3.1.13 NLGI number, n—a numerical scale for classifying
3.1.23 thimble, n—in Soxhlet apparatus, a closed-end po-
the consistency range of lubricating greases and based on the
rous cylinder used to hold the material to be extracted, usually
Test Methods D 217 worked penetration.
5 made of thick matted filter paper but sometimes made of
—NLGI Lubricating Grease Guide
ceramic.
3.1.24 total fluid constituent, n—in lubricating grease
5 analysis, the n-hexane-soluble material extracted from the
Available from National Lubricating Grease Institute, 4635 Wyandotte St.,
Kansas City, MO 64112-1596. lubricating grease sample.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D128–98
3.1.24.1 Discussion—Typical materials include petroleum see Note 4) by distilling from NaOH and neutralizing exactly
oil, non-petroleum fluid, soluble fats, and soluble additives. with NaOH or KOH using phenolphthalein as the indicator.
3.1.25 total n-hexane-insoluble material, n—in lubricating (Precaution—see Note 5.) Dilute with an equal volume of
grease analysis, that portion of grease (excluding free alkali) water.
that is essentially insoluble in n-hexane.
NOTE 4—Warning: Flammable. Denatured. Cannot be made nontoxic.
3.1.25.1 Discussion—Typical materials include thickeners,
NOTE 5—Precaution: In addition to other precautions, avoid skin
fillers, inorganic salts, asphaltenes, or any combinations of
contact or ingestion.
these (also includes insoluble materials found in the analysis of
5.5 Ammonium Carbonate—(NH ) CO .
4 2 3
contaminated grease). Free alkali content is generally insignifi-
NOTE 6—Warning: Harmful if swallowed.
cant.
3.1.26 unsaponifiable matter, n—in lubricating grease, or-
5.6 Butter Yellow Indicator (0.02 g/mL)—Toluene solution
ganic materials, either added or found with fatty materials,
(Warning—see Note 7) of p-dimethylaminoazobenzene.
which do not react during saponification.
(Precaution—see Note 8.)
NOTE 7—Warning: Flammable. Vapor harmful.
4. Significance and Use
NOTE 8—Warning: Suspected carcinogen. Precaution—In addition to
4.1 These test methods can be used to identify and estimate
other precautions, avoid inhalation or skin contact.
the amount of some of the constituents of lubricating greases.
5.7 t-Butyl Alcohol, melting point 24 to 25.5°C (Warning—
These test methods are applicable to many, but not all, greases.
see Note 9).
4.2 Composition should not be considered as having any
direct bearing on service performance unless such correlation
NOTE 9—Warning: Flammable liquid; causes eye burns.
is established.
5.8 Carbon Disulfide (CS ).
NOTE 2—Details on other test methods for grease analysis can be found
NOTE 10—Warning: Extremely flammable. Poison. Vapor may cause
in the following:
flash fire. Vapor harmful. Capable of self-ignition at 100°C or above.
Stanton, G. M., “Examination of Grease by Infrared Spectroscopy,”
Harmful or fatal if swallowed. May be absorbed through the skin.
NLGI Spokesman, Vol 38, No. 5, August 1974, pp 153–165.
Stanton, G. M., “Grease Analysis, a Modern Multitechnique Approach,”
5.9 Ethyl Ether.
Preprint NLGI Annual Meeting, Oct 26–29, 1975.
NOTE 11—Warning: Extremely flammable. Harmful if inhaled. May
Bonomo, F. S., and Schmidt, J. J. E., “Development of Schematic
cause eye injury. Effects may be delayed. May form explosive peroxides.
Analytical Procedures for Synthetic Lubricants and Their Additives,”
Vapors may cause flash fire. Moderately toxic. Irritating to skin.
WADC Technical Report 54-464, Part IV, July 1957 (U.S. Government
No. AD-130922).
5.10 n-Hexane, high-purity grade, conforming to the re-
quirements of Table 1.
5. Reagents
NOTE 12—Warning: Extremely flammable. Harmful if inhaled. May
5.1 Purity of Reagents—Reagent grade chemicals shall be
produce nerve cell damage. Vapors may cause flash fire.
used in all tests. Unless otherwise indicated, it is intended that
5.11 Hydrochloric Acid (37 %)—Concentrated acid (HCl).
all reagents shall conform to the specifications of the Commit-
tee on Analytical Reagents of the American Chemical Society,
NOTE 13—Warning: Poison. Corrosive. May be fatal if swallowed.
where such specifications are available. Other grades may be
Liquid and vapor cause severe burns. Harmful if inhaled.
used, provided it is first ascertained that the reagent is of
5.12 Hydrochloric Acid, Standard Solution (0.5 N)—
sufficiently high purity to permit its use without lessening the
Prepare and standardize a 0.5 N solution of HCl.
accuracy of the determination.
5.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean reagent water conforming
to Specification D 1193, Type III.
5.3 Acetone—American Chemical Society Reagent Grade
n-Hexane, high-purity grade, available from Phillips Petroleum Co., Special
Acetone.
Products Div., Bartlesville, OK, has been found
...
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