Standard Test Method for Measuring Apparent Viscosity of Lubricating Greases

This test method measures the apparent viscosity of lubricating greases across specified temperature and shear-rate ranges to help predict pressure drops in grease distribution systems.

ASTM D1092-26 describes a pressure viscometer method for measuring the apparent viscosity of lubricating greases from −54 °C to 38 °C. The procedure forces a grease sample through capillaries at different flow rates, calculates apparent viscosity from pressure and flow measurements, and plots apparent viscosity versus shear rate. It covers apparatus, sampling, calibration, testing, calculations, precision, bias, and alternative procedures for low-shear-rate measurements. The method uses mercury thermometers, with equivalent temperature-measuring devices permitted under the stated conditions.

Application Scope: Testing lubricating grease rheology and evaluating potential pressure drops in grease distribution systems under steady-state flow conditions at constant temperature.