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ASTM D5481-04

Заменен
Standard Test Method for Measuring Apparent Viscosity at High-Temperature and High-Shear Rate by Multicell Capillary Viscometer — 5 стр.
Значение и использование

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 s1. 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.6

Область применения

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 x 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 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.

ICS
75.100 Lubricants,. Including mineral oils, fluids for metal working and for temporary protection against corrosion / Смазки, индустриальные масла и связанные с ними продукты. Включая минеральные масла, жидкости для обработки металлов и для временной защиты от коррозии
Сборник ASTM
05.02 Petroleum Products, Liquid Fuels, and Lubricants (II): D3711–D6122 / Нефтепродукты, жидкое топливо и смазочные материалы (II): D3711–D6122
Тематика
Petroleum