ASTM D6079 Standard Test Method for Evaluating Lubricity of Diesel Fuels by the High-Frequency Reciprocating Rig (HFRR)
14. Report
14.1 Report the following information:
14.1.1 Major axis, minor axis, and wear scar diameter to the nearest 0.01 mm.
14.1.2 Description of the wear scar area.
14.1.3 Fuel temperature.
14.1.4 Description of the test fuel and date sample taken.
14.1.5 Identification of test specimens.
14.1.6 Date of testing.
14.1.7 Any deviations from the test conditions given in Table 1.
15. Precision and Bias
15.1 Precision - The precision was developed for fuels with wear scar diameters between 0.143 and 0.772 mm at 25°C (0.175 and 1.00 mm at 60°C). The precision data were developed in a 1995 cooperative testing program involving both United States and European testing laboratories. There were nine distinct fluids and each laboratory was given 18 fluids to test. The fluids were blind coded so that replicate samples were not known to the operator. A randomized test sequence was provided and each laboratory was requested to use the same operator and equipment for all 18 samples. Nine laboratories tested the HFRR at 25°C and ten laboratories tested the HFRR at 60°C.
15.1.1 The difference between two test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty:
Repeatability at 25°C = 0.062 mm
Repeatability at 60°C = 0.080 mm
15.1.2 The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty:
Reproducibility at 25°C = 0.127 mm
Reproducibility at 60°C = 0.136 mm
15.2 Bias - The procedure in this test method has no bias because lubricity is not a fundamental and measurable fluid property and thus is evaluated in terms of this test method.
16. Keywords
16.1 boundary lubrication; diesel fuel; friction; lubricity; wear
