ASTM D2981 Test Method for Wear Life of Solid Film Lubricants in Oscillating Motion
9. Procedure
9.1 Conduct the test in a temperature- and humidity-controlled atmosphere (24 +/- 3°C (75 +/- 5°F), 50 +/- 5 %) and allow sufficient static time for the specimens to reach a state of equilibrium.
9.2 With 1.4 kg (3 lb) on the bale rod, which is equivalent to a 13.6 kg (30 lb) normal load on the specimen, start the machine. Standard drive machines will operate only at 87.5 cpm; for variable drive units the 87.5 cpm speed is set before specimens are mounted. Run the machine for 1 min to accomplish initial wear-in of the coated specimen and then stop the machine. Gently lower 27.3 kg (60 lb) of additional weight onto the bale rod, bringing the total to 28.3 kg (63 lb) or 283 kg (630 lb) normal load on the specimen. Start the machine again and run until failure occurs due to excessive friction, as described above. Record friction during the break-in cycle and also record the number of revolutions to failure.
10. Calculation
10.1 Calculate the coefficient of friction from the friction force values as follows:
f = F/W
where:
f = coefficient of friction,
F = friction force, kg (lb), and
W = normal load, kg (lb).
