ASTM D4684-20a

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

SIGNIFICANCE AND USE
5.1 When an engine oil is cooled, the rate and duration of cooling can affect its yield stress and viscosity. In this laboratory test, a fresh engine oil is slowly cooled through a temperature range where wax crystallization is known to occur, followed by relatively rapid cooling to the final test temperature. These laboratory test results have predicted as failures the known engine oils that have failed in the field because of lack of oil pumpability.4 These documented field failing oils all consisted of oils normally tested at –25 °C. These field failures are believed to be the result of the oil forming a gel structure that results in either excessive yield stress or viscosity of the engine oil, or both.  
5.2 Cooling Profiles:  
5.2.1 For oils to be tested at −20 °C or colder, Table X1.1 applies. The cooling profile described in Table X1.1 is based on the viscosity properties of the ASTM Pumpability Reference Oils (PRO). This series of oils includes oils with normal low-temperature flow properties and oils that have been associated with low-temperature pumpability problems (1-5).5 Significance for the −35 °C and −40 °C temperature profiles is based on the data collected from the “Cold Starting and Pumpability Studies in Modern Engines” conducted by ASTM  (6, 7).  
5.2.2 For oils to be tested at −15 °C or −10 °C, Table X1.2 applies. No significance has been determined for this temperature profile because of the absence of appropriate reference oils. Similarly, precision of the test method using this profile for the −10 °C test temperature is unknown. The temperature profile of Table X1.2 is derived from the one in Table X1.1 and has been moved up in temperature, relative to Table X1.1, in consideration of the expected higher cloud points of the viscous oils tested at −15 °C and −10 °C.
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 °C and –40 °C. The precision is stated for test temperatures from –40 °C to –15 °C. The viscosity measurements are made at a shear stress of 525 Pa over a shear rate of 0.4 s–1 to 15 s–1. The viscosity as measured at this shear stress was found to produce the best correlation between the temperature at which the viscosity reached a critical value and borderline pumping failure temperature in engines.  
1.2 This test method contain two procedures: Procedure A incorporates several equipment and procedural modifications from Test Method D4684–02 that have shown to improve the precision of the test, while Procedure B is unchanged from Test Method D4684–02. Additionally, Procedure A applies to those instruments that utilize thermoelectric cooling technology or direct refrigeration technology of recent manufacture for instrument temperature control. Procedure B can use the same instruments used in Procedure A or those cooled by circulating methanol.  
1.3 Procedure A of this test method has precision stated for a yield range from less than 35 Pa to 210 Pa and apparent viscosity range from 4300 mPa·s to 270 000 mPa·s. The test procedure can determine higher yield stress and viscosity levels.  
1.4 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 and gasoline engine oils. The applicability to petroleum products other than engine oils has not been determined.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5.1 Exception—This test method uses the SI based unit of milliPascal second (mPa·s) for viscosity which is equivalent to, centiPoise (cP).  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility...

General Information

• Status: Published
• Publication Date: 31-Oct-2020
• 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)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4684 − 20a
Standard Test Method for
Determination of Yield Stress and Apparent Viscosity of
1
Engine Oils at Low Temperature
This standard is issued under the fixed designation D4684; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* 1.5 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
1.1 This test method covers the measurement of the yield
standard.
stress and viscosity of engine oils after cooling at controlled
1.5.1 Exception—This test method uses the SI based unit of
rates over a period exceeding 45h to a final test temperature
milliPascalsecond(mPa·s)forviscositywhichisequivalentto,
between –10°C and –40°C. The precision is stated for test
centiPoise (cP).
temperatures from –40°C to –15°C. The viscosity measure-
1.6 This standard does not purport to address all of the
ments are made at a shear stress of 525Pa over a shear rate of
–1 –1 safety concerns, if any, associated with its use. It is the
0.4s to 15s . The viscosity as measured at this shear stress
responsibility of the user of this standard to establish appro-
was found to produce the best correlation between the tem-
priate safety, health, and environmental practices and deter-
perature at which the viscosity reached a critical value and
mine the applicability of regulatory limitations prior to use.
borderline pumping failure temperature in engines.
1.7 This international standard was developed in accor-
1.2 This test method contain two procedures: Procedure A
dance with internationally recognized principles on standard-
incorporates several equipment and procedural modifications
ization established in the Decision on Principles for the
from Test Method D4684–02 that have shown to improve the
Development of International Standards, Guides and Recom-
precisionofthetest,whileProcedureBisunchangedfromTest
mendations issued by the World Trade Organization Technical
Method D4684–02.Additionally, ProcedureAapplies to those
Barriers to Trade (TBT) Committee.
instruments that utilize thermoelectric cooling technology or
2. Referenced Documents
direct refrigeration technology of recent manufacture for in-
2
strument temperature control. Procedure B can use the same
2.1 ASTM Standards:
instruments used in ProcedureAor those cooled by circulating
D3829Test Method for Predicting the Borderline Pumping
methanol.
Temperature of Engine Oil
D8278Specification for Digital Contact Thermometers for
1.3 ProcedureAof this test method has precision stated for
Test Methods Measuring Flow Properties of Fuels and
a yield range from less than 35Pa to 210Pa and apparent
Lubricants
viscosity range from 4300mPa·s to 270000mPa·s. The test
E563Practice for Preparation and Use of an Ice-Point Bath
procedure can determine higher yield stress and viscosity
as a Reference Temperature
levels.
3
2.2 ISO Standard:
1.4 This test method is applicable for unused oils, some- ISO 17025General Requirements for the Competence of
times referred to as fresh oils, designed for both light duty and Testing and Calibration Laboratories
heavy duty engine applications. It also has been shown to be ISO Guide 34General Requirements for the Competence of
suitable for used diesel and gasoline engine oils. The applica- Reference Material Producers
bilitytopetroleumproductsotherthanengineoilshasnotbeen
3. Terminology
determined.
3.1 Definitions:
1 2
This test method is under the jurisdiction of ASTM Committee D02 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Subcommittee D02.07 on Flow Properties. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Nov. 1, 2020. Published November 2020. Originally the ASTM website.
3
approved in 1987. Last previous edition approved in 2020 as D4684–20. DOI: Available from International Organization for Standardization (ISO), 1 rue de
10.1520/D4684-20A. Varembé, Case postale 56, CH-1211, Geneva 20, Switzerland, http://www.iso.ch.
*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 State
...

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.
Designation: D4684 − 20 D4684 − 20a
Standard Test Method for
Determination of Yield Stress and Apparent Viscosity of
1
Engine Oils at Low Temperature
This standard is issued under the fixed designation D4684; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. 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 °C and –40 °C. The precision is stated for test temperatures from
–1 –1
–40 °C to –15 °C. The viscosity measurements are made at a shear stress of 525 Pa over a shear rate of 0.4 s to 15 s . The
viscosity as measured at this shear stress was found to produce the best correlation between the temperature at which the viscosity
reached a critical value and borderline pumping failure temperature in engines.
1.2 This test method contain two procedures: Procedure A incorporates several equipment and procedural modifications from Test
Method D4684–02 that have shown to improve the precision of the test, while Procedure B is unchanged from Test Method
D4684–02. Additionally, Procedure A applies to those instruments that utilize thermoelectric cooling technology or direct
refrigeration technology of recent manufacture for instrument temperature control. Procedure B can use the same instruments used
in Procedure A or those cooled by circulating methanol.
1.3 Procedure A of this test method has precision stated for a yield range from less than 35 Pa to 210 Pa and apparent viscosity
range from 4300 mPa·s to 270 000 mPa·s. The test procedure can determine higher yield stress and viscosity levels.
1.4 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 and gasoline engine oils. The applicability to petroleum
products other than engine oils has not been determined.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5.1 Exception—This test method uses the SI based unit of milliPascal second (mPa·s) for viscosity which is equivalent to,
centiPoise (cP).
1.6 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
1
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.07 on Flow Properties.
Current edition approved June 1, 2020Nov. 1, 2020. Published June 2020November 2020. Originally approved in 1987. Last previous edition approved in 20182020 as
D4684 – 18.D4684 – 20. DOI: 10.1520/D4684-20.10.1520/D4684-20A.
*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

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D4684 − 20a
2. Referenced Documents
2
2.1 ASTM Standards:
D3829 Test Method for Predicting the Borderline Pumping Temperature of Engine Oil
D8278 Specification for Digital Contact Thermometers for Test Methods Measuring Flow Properties of Fuels and Lubricants
E563 Practice for Preparation and Use of an Ice-Point Bath as a Reference Temperature
E644 Test Methods for Testing Industrial Resistance Thermometers
E1137 Specification for Industrial Platinum Resistance Thermometers
E2877 Guide for Digital Contact Thermometers
3
2.2 ISO Standard:
ISO 17025 General Requirements for the Competence of Testing and Calibration Laboratories
ISO Guide 34 General Requirements for the Com
...