ASTM D4425-09
(Test Method)Standard Test Method for Oil Separation From Lubricating Grease by Centrifuging (Koppers Method)
Standard Test Method for Oil Separation From Lubricating Grease by Centrifuging (Koppers Method)
SIGNIFICANCE AND USE
This test method is useful in evaluating the degree to which a grease would separate into fluid and solid components when subjected to high centrifugal forces. Flexible shaft couplings, universal joints, and rolling element thrust bearings are examples of machinery which subject lubricating greases to large and prolonged centrifugal forces. This test method has been found to give results that correlate well with results from actual service. The test method may be run at other conditions with agreement between parties but the precision noted in this test method will no longer apply.
SCOPE
1.1 This test method covers a procedure for determining the tendency of lubricating grease to separate oil when subjected to high centrifugal forces.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
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Designation: D4425 − 09
StandardTest Method for
Oil Separation from Lubricating Grease by Centrifuging
1
(Koppers Method)
This standard is issued under the fixed designation D4425; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope* slightly soluble in the liquid lubricant. The general require-
ments are that the solid particles be extremely small, uniformly
1.1 This test method covers a procedure for determining the
dispersed, and capable of forming a relatively stable, gel-like
tendencyoflubricatinggreasetoseparateoilwhensubjectedto
structure with the liquid lubricant.
high centrifugal forces.
3.2 Symbols:
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
a = distance from top of grease surface to tube mouth
standard.
(mm).
1.3 This standard does not purport to address all of the
b = height of liquid column in an inverted test tube (mm).
d = test tube inside diameter (mm).
safety concerns, if any, associated with its use. It is the
H = accumulated test time at a given reading (h).
responsibility of the user of this standard to establish appro-
K36 = resistance to centrifugal separation (V/H).
priate safety and health practices and determine the applica-
r = measured at the maximum radius of rotation (mm).
bility of regulatory limitations prior to use.
rpm = rotational speed (r/min).
V = volume of separated oil, as a percentage of the
2. Referenced Documents
original grease volume (%).
2
2.1 ASTM Standards:
3
V = grease volume in a test tube (cm ).
g
D217 Test Methods for Cone Penetration of Lubricating
3
V = volume of separated oil (cm ).
o
3
Grease
V = test tube total volume (cm ).
t
A = angle of rotor, between the test tube axis and axis of
3. Terminology
rotation (degrees).
3.1 Definitions:
ω = rotational speed (rad/s).
3.1.1 lubricating grease, n—a semi-fluid to solid product of
G = relative centrifugal acceleration.
a thickener in a liquid lubricant.
3.3 The relative effect of centrifugal forces, when related to
3.1.1.1 Discussion—The dispersion of the thickener forms a
2
the gravitational standard acceleration (9.81 m/s ), is noted
two-phase system and immobilizes the liquid lubricant by
with the symbol G. It can be calculated as follows:
surface tension and other physical forces. Other ingredients are
24 2
G 5 1.02 310 3r 3ω (1)
commonly included to impart special properties. D217
or
3.1.2 thickener, n—in lubricating grease, a substance com-
26 2
G 5 1.12 310 3r 3rpm¯ (2)
posed of finely-divided particles dispersed in a liquid to form
the products’s structure.
4. Summary of Test Method
3.1.2.1 Discussion—Thickeners can be fibers (such as vari-
4.1 Pairs of centrifuge tubes are charged with grease
ous metallic soaps) or plates or spheres (such as certain
samples and are placed in the centrifuge. The grease samples
non-soapthickeners),whichareinsolubleor,atmost,onlyvery
are subjected to a centrifugal force equivalent to a G value of
36 000, at 50°C 6 1°C, for specific periods of time. The
1
This test method is under the jurisdiction of Committee D02 on Petroleum
resistance of the grease to separate the oil is then defined as a
ProductsandLubricantsandisthedirectresponsibilityofSubcommitteeD02.G0.03
ratioofthepercentofoilseparatedtothetotalnumberofhours
on Physical Tests.
of testing.
Current edition approved April 15, 2009. Published May 2009. Originally
approved in 1984. Last previous edition approved in 2002 as D4425–97(2002).
5. Significance and Use
DOI: 10.1520/D4425-09.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.1 This test method is useful in evaluating the degree to
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
which a grease would separate into fluid and solid components
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. when subjected to high centrifugal forces. Flexible shaft
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D4425 − 09
couplings, universal joints, and rolling element thrust bearings 9.1.1 Determinethetotalvolume, V,incubiccentimetres,of
areexamplesofmachinerywhichsubjectlubricatinggreasesto each tube by filling with water and then pouring into a
large and prolonged centrifugal forces. This test method has graduated cylinder and measuring.
been found to give results that correlate well with results from 9.1.2
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
An American National Standard
Designation:D4425–97 (Reapproved 2002) Designation:D4425–09
Standard Test Method for
Oil Separation from Lubricating Grease by Centrifuging
1
(Koppers Method)
This standard is issued under the fixed designation D 4425; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1This test method describes a procedure for determining the tendency of lubricating grease to separate oil when subjected to
high centrifugal forces.
1.2*
1.1 This test method covers a procedure for determining the tendency of lubricating grease to separate oil when subjected to
high centrifugal forces.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
1.3The values stated in SI units are to be regarded as the standard.
2. Referenced Documents
2
2.1 ASTM Standards:
D 217 Test Methods for Cone Penetration of Lubricating Grease
3. Terminology
3.1 Definitions:
3.1.1 lubricating grease, n—a semi-fluid to solid product of a thickener in a liquid lubricant.
3.1.1.1 Discussion—The dispersion of the thickener forms a two-phase system and immobilizes the liquid lubricant by surface
tension and other physical forces. Other ingredients are commonly included to impart special properties. D 217
3.1.2 thickener, n—in lubricating grease, a substance composed of finely-divided particles dispersed in a liquid to form the
products’s structure.
3.1.2.1 Discussion—Thickeners can be fibers (such as various metallic soaps) or plates or spheres (such as certain non-soap
thickeners), which are insoluble or, at most, only very slightly soluble in the liquid lubricant. The general requirements are that
the solid particles be extremely small, uniformly dispersed, and capable of forming a relatively stable, gel-like structure with the
liquid lubricant.
3.2 Symbols:
a = distance from top of grease surface to tube mouth (mm).
b = height of liquid column in an inverted test tube (mm).
d = test tube inside diameter (mm).
H = accumulated test time at a given reading (h).
K36 = resistance to centrifugal separation (V/H).
r = measured at the maximum radius of rotation (mm).
rpm = rotational speed (r/min).
1
This test method is under the jurisdiction of Committee D02 on Petroleum Products and is the direct responsibility of Subcommittee D02.G on Lubricating Grease.
Current edition approved June 10, 1997. Published October 1997. Originally published as D4425–84. Last previous edition D4425–90.
1
This test method is under the jurisdiction of Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.G0.03 on
Physical Tests.
Current edition approved April 15, 2009. Published May 2009. Originally approved in 1984. Last previous edition approved in 2002 as D 4425–97(2002).
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 05.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
D4425–09
V = volume of separated oil, as a percentage of the original grease volume (%).
3
V = grease volume in a test tube (cm ).
g
3
V = volume of separated oil (cm ).
o
3
V = test tube total volume (cm ).
t
A = angle of rotor, between the test tube axis and axis of rotation (degrees).
v = rotational speed (rad/s).
G = relative centrifugal acceleration.
The
2
3.3 The relative effect of centrifugal forces, when related to the gravitational standard acceleration (9.81 m/s ), is noted with
the symbol G. It can be calculated as follows:
24 2
G 5 1.02 3 10 3 r3v , (1)
or 2
or
26 2
G 5 1.12 3 10 3 r 3 rpm¯ (2)
4. Summary of Test Method
4.1 Pairs of centrifuge tubes are charged with grease samples and are placed i
...
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