ASTM D5183 Standard Test Method for Determination of the Coefficient of Friction of Lubricants Using the Four-Ball Wear Test Machine
12. Report
12.1 Report the following information:
12.1.1 Average wear-in scar, mm,
12.1.2 Coefficient of friction for each increment of 10 kgf,
12.1.3 Incipient seizure load, kilogram force, and
12.1.4 Final average wear scar, mm.
13. Precision and Bias
13.1 Precision - The precision of this test method as determined by the statistical examination of interlaboratory test results is as follows:
13.1.1 Repeatability - The difference between successive 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 values only in one case in twenty.
13.1.2 Reproducibility - 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, exceed the following values only in one case in twenty.
NOTE 6 - Precision data is based on the coefficient of friction values determined according to this test method at 40 kg load using balls from random lots.
13.2 Bias - Since there is no accepted reference material suitable for determining the bias for the procedure in Test Method D5183 for measuring coefficient of friction, bias has not been determined.
14. Keywords
14.1 coefficient of friction; Four-Ball Wear test machine; friction