ASTM D6079 Standard Test Method for Evaluating Lubricity of Diesel Fuels by the High-Frequency Reciprocating Rig (HFRR)
11. Procedure
11.1 Table 1 summarizes the test conditions.
11.2 Strict adherence to cleanliness requirements and to the specified cleaning procedures is required. During handling and installation procedures, protect cleaned test parts (disks, balls, reservoir, and fixtures) from contamination by using clean forces and wearing clean cotton gloves.
11.3 Using forceps, place the test disk into the test reservoir, shiny side up. Secure the test disk to the test reservoir and the test reservoir to the test apparatus. Ensure the unit's thermocouple is properly placed in the reservoir. Ensure the relative humidity in the test laboratory is greater than 30 %.
11.4 Using forceps, place the test ball into the holder and attach the holder to the end of the vibrator arm. Ensure the holder is horizontal before fully securing the unit.
11.5 Using a pipette, place 2 +/- 0.2 mL of the test fuel into the bath.
11.6 Set the temperature controller to the desired test temperature (25°C or 60°C, preferably 60°C, see 4.1) and switch on the heater. Set the stroke length to 1 mm. Set the vibration frequency to 50 Hz.
11.7 When the temperature has stabilized, lower the vibrator arm and suspend a 200-g weight from the arm. Start the vibrator unit.
11.8 Operate the test for 75 min. At the completion of the test, switch off the vibrator unit and the heater. Lift up the vibrator arm and remove the test ball holder.
11.9 Rinse the test ball (still in the holder) in cleaning solvents and dry with a tissue. Using a permanent marker, circle the wear scar on the ball.
11.10 Remove the test reservoir and properly dispose of the fuel. Remove the test disk and wipe it clean. Place the disk in a storage receptacle (plastic bag) marked with the unique test reference.
11.11 Place the test ball holder under the microscope and measure the wear scar diameter in accordance with Section 12
11.12 Upon completion of the wear scar measurement, remove the test ball from the holder and place the ball together in storage with the test disk.
12. Measure of the Wear Scar
12.1 Turn on the microscope light and position the test ball under microscope at 100x magnification.
12.2 Focus the microscope and adjust the stage such that the wear scar is centered within the field of view.
12.3 Align the wear scar to a divisional point of reference on the numerical scale with the mechanical stage controls. Measure the major axis to the nearest 0.01 mm. Record the readings on the data sheet.
12.4 Align the wear scar to a divisional point of reference on the numerical scale with the mechanical stage controls. Measure the minor axis to the nearest 0.01 mm. Record the readings on the data sheet.
12.5 Record the condition of the wear area if different from the reference standard test, that is, debris color, unusual particles or wear pattern, visible galling, and so forth, and presence of particles in the test reservoir.
13. Calculation
13.1 Calculate the wear scar diameter as follows:
WSD = (M + N)/2
where:
WSD = wear scar diameter, mm,
M = major axis, mm, and
N = minor axis, mm.
