ASTM D5481-10
Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer

Standard No.

ASTM D5481-10

Release Date

2010

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D5481-13

Latest

ASTM D5481-21

Scope

Viscosity is an important property of fluid lubricants. The viscosity of all fluids varies with temperature. Many common petroleum lubricants are non-Newtonian: their viscosity also varies with shear rate. The usefulness of the viscosity of lubricants is greatest when the viscosity is measured at or near the conditions of shear rate and temperature that the lubricants will experience in service.

The conditions of shear rate and temperature of this test method are thought to be representative of those in the bearing of automotive engines in severe service.

Many equipment manufacturers and lubricant specifications require a minimum high-temperature high-shear viscosity at 150°C and 10⁶ s⁻¹. The shear rate in capillary viscometers varies across the radius of the capillary. The apparent shear rate at the wall for this test method is increased to compensate for the variable shear rate.³

This test was evaluated in an ASTM cooperative program.

1.1 This test method covers the laboratory determination of high-temperature high-shear (HTHS) viscosity of engine oils at a temperature of 150°C using a multicell capillary viscometer containing pressure, temperature, and timing instrumentation. The shear rate for this test method corresponds to an apparent shear rate at the wall of 1.4 million reciprocal seconds (1.4 × 10⁶ s⁻¹). This shear rate has been found to decrease the discrepancy between this test method and other high-temperature high-shear test methods³ used for engine oil specifications. Viscosities are determined directly from calibrations that have been established with Newtonian oils with viscosities from 2 to 5 mPa-s at 150°C.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.2.1 The centiPoise (cP) is a non-SI metric unit of viscosity that is numerically equal to the milliPascal-second (mPa-s).

1.2.2 Pounds per square inch (psi) is a non-SI unit of pressure that is approximately equal to 6.895 kPa. These units are provided for information only in 6.1.1, 7.3, 9.1.2.1, and the tables.

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.

ASTM D5481-10 Referenced Document

• ASTM D4683 Standard Test Method for Measuring Viscosity at High Shear Rate and High Temperature by Tapered Bearing Simulator
• ASTM D4741 Standard Test Method for Measuring Viscosity at High Temperature and High Shear Rate by Tapered-Plug Viscometer

ASTM D5481-10 history

• 2021 ASTM D5481-21 Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
• 2020 ASTM D5481-20a Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
• 2020 ASTM D5481-20 Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
• 2020 ASTM D5481-13(2020) Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
• 2013 ASTM D5481-13 Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
• 2010 ASTM D5481-10 Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
• 2004 ASTM D5481-04 Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
• 1996 ASTM D5481-96(2001) Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer
• 1996 ASTM D5481-96 Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer