ASTM D6821-20a

Standard Test Method for Low Temperature Viscosity of Drive Line Lubricants in a Constant Shear Stress Viscometer

SIGNIFICANCE AND USE
5.1 Viscosity of drive line lubricants at low temperature is critical for both gear lubrication and the circulation of the fluid in automatic transmissions. For gear oils (GOs), the issue is whether the fluid characteristics are such that the oil will flow into the channel dug out by the submerged gears as they begin rotating and re-lubricating them as they continue to rotate. For automatic transmission fluids, torque, and tractor fluids the issue is whether the fluid will flow into a pump and through the distribution system rapidly enough for the device to function.  
5.2 The low temperature performance of drive line lubricant flow characteristics was originally evaluated by the channel test. In this test, a pan was filled to a specified depth of approximately 2.5 cm and then cooled to test temperature. The test was performed by scraping a channel through the full depth of the fluid and across the length of the pan after it had soaked at test temperature for a specified time. The time it took the fluid to cover the channel was measured and reported. The channel test was replaced by Test Method D2983 in 1971.  
5.3 The results of this test procedure correlate with the viscometric measurements obtained in Test Method D2983.4 The correlation obtained is:
   where:
  V  =  the apparent viscosity measured by this test method, and   VD2983  =  the apparent viscosity measured by Test Method D2983.    
5.3.1 The equation was obtained by forcing the fit through zero. The coefficient of variation (R2) for this correlation is 0.9948.
SCOPE
1.1 This test method covers the measurement of the viscosity of drive line lubricants (gear oils, automatic transmission fluids, and so forth) with a constant shear stress viscometer at temperatures from –40 °C to 10 °C after a prescribed preheat and controlled cooling to the final test temperature. The precision is stated for test temperatures from –40 °C to –26 °C.  
1.2 The applicability of this particular test method to petroleum products other than drive line lubricants has not been determined.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3.1 This standard uses the SI based unit of milliPascal second (mPa·s) for viscosity which is equivalent to centiPoise (cP).  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 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.

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: D6821 − 20a
Standard Test Method for
Low Temperature Viscosity of Drive Line Lubricants in a
1
Constant Shear Stress Viscometer
This standard is issued under the fixed designation D6821; 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.
1. Scope* cants using a Rotational Viscometer
D3829Test Method for Predicting the Borderline Pumping
1.1 This test method covers the measurement of the viscos-
Temperature of Engine Oil
ity of drive line lubricants (gear oils, automatic transmission
D4684Test Method for Determination of Yield Stress and
fluids, and so forth) with a constant shear stress viscometer at
Apparent Viscosity of Engine Oils at Low Temperature
temperatures from –40°C to 10°C after a prescribed preheat
D6896Test Method for Determination of Yield Stress and
and controlled cooling to the final test temperature. The
ApparentViscosity of Used Engine Oils at LowTempera-
precisionisstatedfortesttemperaturesfrom–40°Cto–26°C.
ture
1.2 The applicability of this particular test method to petro-
D8278Specification for Digital Contact Thermometers for
leum products other than drive line lubricants has not been
Test Methods Measuring Flow Properties of Fuels and
determined.
Lubricants
E563Practice for Preparation and Use of an Ice-Point Bath
1.3 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this as a Reference Temperature
3
2.2 ISO Standards:
standard.
1.3.1 This standard uses the SI based unit of milliPascal ISO 17025General Requirements for the Competence of
Testing and Calibration Laboratories
second (mPa·s) for viscosity which is equivalent to centiPoise
(cP). ISO Guide 34General Requirements for the Competence of
Reference Material Producers
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety, health, and environmental practices and deter-
3.1.1 apparent viscosity, n—the determined viscosity ob-
mine the applicability of regulatory limitations prior to use.
tained by the use of this test method.
1.5 This international standard was developed in accor-
3.1.2 digital contact thermometer (DCT), n—an electronic
dance with internationally recognized principles on standard-
device consisting of a digital display and associated tempera-
ization established in the Decision on Principles for the
ture sensing probe.
Development of International Standards, Guides and Recom-
3.1.2.1 Discussion—This device consists of a temperature
mendations issued by the World Trade Organization Technical
sensor connected to a measuring instrument; this instrument
Barriers to Trade (TBT) Committee.
measures the temperature-dependent quantity of the sensor,
2. Referenced Documents
computes the temperature from the measured quantity, and
2
provides a digital output. This digital output goes to a digital
2.1 ASTM Standards:
displayand/orrecordingdevicethatmaybeinternalorexternal
D2983Test Method for Low-Temperature Viscosity of Au-
to the device.
tomaticTransmissionFluids,HydraulicFluids,andLubri-
3.1.2.2 Discussion—The devices are often referred to as a
“digitalthermometers,”howeverthetermincludesdevicesthat
1
This test method is under the jurisdiction of ASTM Committee D02 on
sense temperature by means other than being in physical
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
contact with the media.
Subcommittee D02.07 on Flow Properties.
3.1.2.3 Discussion—PET is an acronym for portable elec-
Current edition approved Nov. 1, 2020. Published November 2020. Originally
approved in 2002. Last previous edition approved in 2020 as D6821–20. DOI:
tronic thermometers, a subset of digital contact thermometers
10.1520/D6821-20A.
(DCT).
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
*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

---------------------
...

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: D6821 − 20 D6821 − 20a
Standard Test Method for
Low Temperature Viscosity of Drive Line Lubricants in a
1
Constant Shear Stress Viscometer
This standard is issued under the fixed designation D6821; 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*
1.1 This test method covers the measurement of the viscosity of drive line lubricants (gear oils, automatic transmission fluids, and
so forth) with a constant shear stress viscometer at temperatures from –40 °C to 10 °C after a prescribed preheat and controlled
cooling to the final test temperature. The precision is stated for test temperatures from –40 °C to –26 °C.
1.2 The applicability of this particular test method to petroleum products other than drive line lubricants has not been determined.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3.1 This standard uses the SI based unit of milliPascal second (mPa·s) for viscosity which is equivalent to centiPoise (cP).
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D2983 Test Method for Low-Temperature Viscosity of Automatic Transmission Fluids, Hydraulic Fluids, and Lubricants using
a Rotational Viscometer
D3829 Test Method for Predicting the Borderline Pumping Temperature of Engine Oil
D4684 Test Method for Determination of Yield Stress and Apparent Viscosity of Engine Oils at Low Temperature
D6896 Test Method for Determination of Yield Stress and Apparent Viscosity of Used Engine Oils at Low Temperature
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
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 2002. Last previous edition approved in 20182020 as
D6821 – 18.D6821 – 20. DOI: 10.1520/D6821-20.10.1520/D6821-20A.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
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 ----------------------
D6821 − 20a
3
2.2 ISO Standards:
ISO 17025 General Requirements for the Competence of Testing and Calibration Laboratories
ISO Guide 34 General Requirements for the Competence of Reference Material Producers
3. Terminology
3.1 Definitions:
3.1.1 apparent viscosity, n—the determined viscosity obtained by the use of this test method.
3.1.2 digital contact thermometer (DCT), n—an electronic device consisting of a digital display and associated temperature
sensing probe.
3.1.2.1 Discussion—
This device consists of a temperature sensor connected to a measuring instrument; this instrument measures the temperature-
dependent quantity of the sensor, computes the temperature from the measured quantity, and provides a digital output. This digital
output goes to a digital display and/or recording device that may be internal or external to the device. These devices are s
...