ASTM D1092 test method for measuring apparent viscosity of lubricating greases
1. Scope
1.1 This test method covers measurement, in poises, of the apparent viscosity of lubricating greases in the temperature range from -54 to 38°C (-65 to 100°F). Measurements are limited to the range from 25 to 100 000 P at 0.1 s(-1) and 1 to 100 P at 15 000 s(-1).
NOTE 1 - At very low temperatures the shear rate range may be reduced because of the great force required to force grease through the smaller capillaries. Precision has not been established below 10 s(-1).
1.2 This standard uses inch-pound units as well as SI (acceptable metric) units. The values stated first are to be regarded as standard. The values given in parentheses are for information only. The capillary dimensions in SI units in Fig. A1.1 and Fig. A1.2 are 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.
2. Referenced Documents
2.1 ASTM Standards:
D88 Test Method for Saybolt Viscosity
D217 Test Methods for Cone Penetration of Lubricating Grease
D3244 Practice for Utilization of Test Data to Determine Conformance with Specifications
3. Terminology
3.1 Definitions:
3.1.1 apparent viscosity, n - of a lubricating grease is the ratio of shear stress to shear rate calculated from Poiseuille's equation, and is measured in poises (see 10.1).
3.1.2 capillary, n - For the purpose of this method, a capillary is any right cylindrical tube having a length to diameter ratio of 40 to 1.
3.1.3 shear rate, n - the rate at which a series of adjacent layers of grease move with respect to each other; proportional to the linear velocity of flow divided by the capillary radius, and is thus expressed as reciprocal seconds.
