ASTM D1092 - Measuring Apparent Viscosity of Lubricating Greases

Significance and Use

5.1 Apparent viscosity versus shear rate information can be useful in predicting pressure drops in grease distribution systems under steady-state flow conditions at constant temperature.

Scope

1.1 This test method covers measurement, in poises, of the apparent viscosity of lubricating greases in the temperature range from −54 °C to 38 °C (−65 °F to 100 °F). Measurements are limited to the range from 25 P to 100 000 P at 0.1 s−1 and 1 P 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 test method uses mercury thermometers. WARNING—Mercury has been designated by many regula-tory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location. The responsible subcommittee, D02.G0, continues to explore alternatives to eventually replace the mercury thermometers.

1.3.1 In addition, temperature measuring devices such as liquid-in-glass thermometers (Specification E1), thermocouples, thermistors, or platinum resistance thermometers that provide equivalent or better accuracy and precision, that cover the temperature range for ASTM thermometer 49C, may be used.

Extracted, with permission, from ASTM D1092-20 - Measuring Apparent Viscosity of Lubricating Greases, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be purchased from ASTM International, astm.org