ASTM D3704 Test Method for Wear Preventive Properties of Lubricating Greases
ASTM D3704 Standard Test Method for Wear Preventive Properties of Lubricating Greases Using the (Falex) Block on Ring Test Machine in Oscillating Motion
8. Calibration and Standardization
8.1 Run Test Method D2714 calibration procedure to ensure good mechanical operation of test equipment.
9. Procedure
9.1 Before each test, clean the apparatus with appropriate solvent chosen in 7.3 and blow dry.
9.2 Select a new test ring and block, wash with solvent, and dry with clean soft cloth or paper.
9.3 The grease sample should be worked 60 strokes, one-half scale or one-quarter scale (Test Method D1403), prior to starting runs. One working per running day is sufficient. For those who may not have small workers, working briefly with a spatula is sufficient.
9.4 Adjust the amplitude of oscillation for the desired arc.
9.5 Lubricate the quarter segment (or the ball seat) of the specimen holder with the grease to be tested.
9.6 With no weights on the bale rod, apply a thin film of the test grease to the surface of a clean test block and mount the test block in the quarter segment (or ball seat) and position both securely in the specimen holder. On models with the ball seat, tighten the set screws so that the block is held lightly. Apply a thin film of the test grease along the test surface of the ring, and slip it on over the test shaft, taking care that grease does not get on the seat and the test surfaces are not scratched. Alternatively, the ungreased ring may be slipped on and tightened down and grease carefully applied to the ring surface with a small, thin spatula. Screw on the lock washer and locknut, and tighten with a torque wrench to 250 in.•lb (28.25 N•m). Apply additional test grease to the area of the test block, especially the area that overlaps the ring on both sides of the block. (Total grease is 1 to 2 g.)
9.7 The block should be seated squarely on the ring; otherwise, a wedge-shaped scar will result. One way to accomplish this is to loosen the block in the holder, apply a 3-lb (1.3-kg) load on the bale rod and rotate the ring by hand back and forth a few times. This also serves to distribute the grease between block and ring. The block is then tightened securely for running. If grease has pulled away from the block during the above operation, it should be reapplied as described in 9.6.
9.8 Place the desired weights on the bale rod keeping in mind the standard machine is built with a 10:1 ratio lever. Make sure the two load lever reference markers are aligned. If so equipped, position the friction force cutoff level at 40 lb (18.14 kg).
9.9 Starting at zero, bring the speed up rapidly to the predetermined setting necessary to give the desired speed. Measure time as soon as oscillation begins.
9.10 Run for desired time. Disassemble and wipe off the block and ring. Using the required microscope, measure the scar width on the test block in the center and 1 mm away from each edge to the nearest 0.01 mm. Report the average of these three measurements.
9.11 Report any unusual observation or an automatic friction cutoff. If a machine malfunctions or a test block has a wedge shaped scar, the test should be rerun.
