Active Standard ASTM D6821 | Developed by Subcommittee: D02.07
Book of Standards Volume: 05.03
Historical (view previous versions of standard)
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.
|V||=||the apparent viscosity measured by this test method, and|
|V D2983||=||the apparent viscosity measured by Test Method D2983.|
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 to 10°C after a prescribed preheat and controlled cooling to the final test temperature. The precision is stated for test temperatures from -40 to -26°C.
1.3.1 This standard uses the SI based unit of milliPascal second (mPa·s) for viscosity which is equivalent to centiPoise (cP).
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D2983 Test Method for Low-Temperature Viscosity of Lubricants Measured by Brookfield 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
ICS Number Code 75.100 (Lubricants, industrial oils and related products)
UNSPSC Code 15120000(Lubricants and oils and greases and anti corrosives); 41103312(Viscosimeters)