ASTM D4684-02

Standard Test Method for Determination of Yield Stress and Apparent Viscosity of Engine Oils at Low Temperature

SCOPE
1.1 This test method covers the measurement of the yield stress and viscosity of engine oils after cooling at controlled rates over a period exceeding 45 h to a final test temperature between 10 and 40°C. The viscosity measurements are made at a shear stress of 525 Pa over a shear rate of 0.4 to 15 s-1.
1.2 This test method is applicable for unused oils, sometimes referred to as fresh oils, designed for both light duty and heavy duty engine applications. It also has been shown to be suitable for used diesel oils. The applicability to petroleum products other than engine oils has not been determined.
1.3 This test method uses the millipascal second (m·Pas) as the unit of viscosity. For information, the equivalent centipoise unit is shown in parentheses.
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.

General Information

• Status: Historical
• Publication Date: 09-Aug-2002
• ICS: 75.100 - Lubricants, industrial oils and related products
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.07 - Flow Properties

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
An American National Standard
Designation: D 4684 – 02
Standard Test Method for
Determination of Yield Stress and Apparent Viscosity of
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Engine Oils at Low Temperature
This standard is issued under the fixed designation D 4684; 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.
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1. Scope *
2~V!R
s
G 5 (1)
r 2 2
R 2 R
1.1 This test method covers the measurement of the yield
s r
stress and viscosity of engine oils after cooling at controlled 2
4~p! R
s
5 (2)
rates over a period exceeding 45 h to a final test temperature
2 2
t ~R 2 R !
s r
between −10 and −40°C. The viscosity measurements are
made at a shear stress of 525 Pa over a shear rate of 0.4 to 15
where:
−1
s . G = shear rate at the surface of the rotor in reciprocal
r
−1
1.2 This test method is applicable for unused oils, some- seconds, s ,
times referred to as fresh oils, designed for both light duty and V = angular velocity, rad/s,
R = stator radius, mm,
heavy duty engine applications. It also has been shown to be s
R = rotor radius, mm, and
suitable for used diesel oils. The applicability to petroleum r
t = time in seconds for one revolution of the rotor.
products other than engine oils has not been determined.
For the specific apparatus being described in 5.1.1,
1.3 This test method uses the millipascal second (mPa·s) as
the unit of viscosity. For information, the equivalent centipoise G 5 63/t (3)
r
unit is shown in parentheses.
2.1.5 shear stress—the motivating force per unit area for
1.4 This standard does not purport to address all of the
fluid flow. For the rotary viscometer being described, the rotor
safety concerns, if any, associated with its use. It is the
surface is the area under shear or the shear area.
responsibility of the user of this standard to establish appro-
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T 5 9.81 M ~R 1 R ! 3 10 (4)
r o t
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. T
r
9
S 5 3 10 (5)
r 2
2 ~p!R h
r
2. Terminology
where:
2.1 Definitions:
T = torque applied to rotor, N·m,
r
2.1.1 apparent viscosity—the determined viscosity obtained
M = applied mass, g,
by use of this test method.
R = radius of the shaft, mm,
o
2.1.2 Newtonian oil or fluid—an oil or fluid that at a given
R = radius of the string, mm,
t
temperature exhibits a constant viscosity at all shear rates or
S = shear stress at the rotor surface, Pa, and
r
shear stresses.
h = height of the rotor, mm.
2.1.3 non-Newtonian oil or fluid—an oil or fluid that at a
For the dimensions given in 5.1.1,
given temperature exhibits a viscosity that varies with chang-
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T 5 31.7 M 3 10 (6)
ing shear stress or shear rate. r
2.1.4 shear rate—the velocity gradient in fluid flow. For a S 5 3.5 M (7)
r
Newtonian fluid in a concentric cylinder rotary viscometer in
2.1.6 viscosity—the ratio between the applied shear stress
which the shear stress is measured at the inner cylinder surface
and rate of shear, sometimes called the coefficient of dynamic
(such as this apparatus, described in 5.1), and ignoring any end
viscosity. This value is thus a measure of the resistance to flow
effects, the shear rate is given as follows:
of the liquid. The SI unit of viscosity is the pascal second
[Pa·s]. A centipoise (cP) is one millipascal second [mPa·s].
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2.2 Definitions of Terms Specific to This Standard:
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
2.2.1 calibration oils—those oils that establish the instru-
D02.07.0C on Low Temperature Rheology of Non-Newtonian Fluids.
ment’s reference framework of apparent viscosity versus
Current edition approved Aug. 10, 2002. Published October 2002. Originally
e1 speed, from which the apparent viscosities of test oils are
published as D 4684–87. Last previous edition D 4684–99 .
*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.
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D4684–02
determined. Calibration oils, which are essentially Newtonian ture profile because of the absence of appropriate reference
fluids, are available commercially, and have an approximate oils. Similarly, precision of the test method using this profile
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viscosity of
...