ASTM D5183 Determination of the Coefficient of Friction of Lubricants
ASTM D5183 Standard Test Method for Determination of the Coefficient of Friction of Lubricants Using the Four-Ball Wear Test Machine
6. Apparatus
6.1 Four-Ball Test Machine - See Fig. 1, Fig. 2, and Fig. 3.
NOTE 1 - It is important to distinguish between the Four-Ball E.P. and the Four-Ball Wear Test Machine (see Test Method D4172). The Four-Ball E.P. Test Machine is designed for testing under heavier loads and lacks the sensitivity necessary for wear tests.
6.2 Microscope, capable of measuring the diameters of the scars produced on the three balls to an accuracy of 0.01 mm without removal from the ball test cup.
6.3 Test Balls, chrome alloy steel, made from AISI Standard Steel No. E-52100, with diameter of 12.7 mm (0.5 in.) Grade 25 EP (extra polish). Such balls are described in ANSI Specifications B 3.12. The extra-polish finish is not described in that specification. The Rockwell C hardness shall be 64 to 66, a closer limit than is found in the ANSI requirement.
7. Reagents and Materials
7.1 Purity of Reagents - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.
7.2 Wear-In Lubricant, white oil having a viscosity at 40°C of 24.3 to 26.1 cSt (100°F of 125/135 SUS). It should be percolated through activated alumina to remove any residual impurities.
7.3 Acetone. (Warning - Flammable. Health hazard.)
7.4 n-Heptane. (Warning - Flammable. Health hazard.)
7.5 Methyl ethyl ketone. (Warning - Flammable. Health hazard.)
7.6 Pyridine. (Warning - Flammable. Health hazard.)
