ASTM D6895 Standard Test Method for Rotational Viscosity of Heavy Duty Diesel Drain Oils at 100°C
6. Apparatus
6.1 This test method uses rheometers/viscometers of the controlled stress or controlled rate mode of operation. The test method requires the use of concentric cylinder measuring geometry or cone and plate measuring geometries, with a minimum cone diameter of 50 mm, capable of operating in the range of approximately 0.1 to 10 Pa for shear stress and 10 to 300 s(-1) for shear rate.
6.2 Instrument data logging or software shall be capable of delivering shear stress versus shear rate data and viscosity versus shear rate data in tabular form. During the experiment, a minimum of 20 points must be taken. The method for data logging shall be an equilibrium method where the controlled stress or controlled rate value is held constant until the data point equilibrium is reached. The use of a maximum point time is acceptable, but it must be set to at least 30 s.
6.3 Temperature shall be controlled to 100 +/- 0.2°C at equilibrium. Some rheometers have a 99.9°C set point limit and would be acceptable for this test method.
7. Reagents and Materials
7.1 Standard Newtonian Reference Oil, calibrated in viscosity in the range of 12 to 35 mPa·s at 100°C.
