ASTM D5969 Test Method for Corrosion-Preventive Properties of Lubricating Greases
ASTM D5969 Standard Test Method for Corrosion-Preventive Properties of Lubricating Greases in Presence of Dilute Synthetic Sea Water Environments
10. Procedure
10.1 With the reservoir of the grease packer resting on a clean bench top, and while wearing gloves, place the bearing cup with the small diameter face down into the recess of the packer. Place the bearing cone over the cut, and while holding the bearing assembly against the packer, lift and invert the whole unit and return it to the bench.
10.2 Fill the reservoir with the grease sample, and use the plunger to force grease through the bearing. Carefully remove the plunger from the reservoir to avoid sucking air into the bearing, and slide the packer unit over the edge of the bench. While holding the bearing assembly in the packer, invert the unit to its original position on the bench.
10.3 Using a small square-ended spatula, remove excess grease from the bearing bore and the annulus between the grease packer and outer perimeter of the bearing cup. The bearing is removed from the packer by either the use of the pliers or by placing a gloved index finger in the bore and lifting it out.
10.3.1 While holding the bearing, use the spatula to remove excess grease above the cage on both sides of the bearing. This procedure is done to ensure that approximately the same volume of grease is used each time.
10.4 Using Fig. 1 as a guide, hold the packed bearing between gloved fingers with the large inside diameter of the cup downward and insert the small diameter plastic flange on top of the bore, and the larger flange into the bottom of the bore. Slide the bearing assembly onto the 1-kg weight so that the large diameter flange fits into the recess on top of the weight. Insert the bolt through the assembly and screw the bolt tightly into the weight. Lower the plastic bearing holder (Part 8) over the bearing. (The large O-ring faces upward.) Press down the holder so that the bearing fits squarely into the holder.
10.5 Invert a plastic jar over the bearing assembly. Slide the two components over the edge of the bench, and with fingers pressing the weight against the inner bottom of the jar, invert the entire assembly.
10.6 Place the jar onto the base of the motor-driven spindle and center under the indexing pin of the drive. After the pin is engaged, start the motor and bring the drive into the center of the 1-kg weight. Load until the nut hits the depth stop. Run for 60 +/- 3 s and allow the bearing to coast to a stop. Hold it with two fingers and then raise the drive. Take extreme care not to break the contact between the races and rollers at this point and in the following steps.
NOTE 7 - At no time during or after the 60-s run shall the grease be redistributed or forced back into the bearing.
10.7 Using synthetic sea water (Warning - see Note 4) prepared as in Test Method D665, make a dilution with distilled water (by volume, at the desired concentration) to obtain the proper test solution. The synthetic sea water should be no more than one week old.
10.8 Fill a clean syringe with 100 +/- 5 mL of the freshly prepared synthetic sea water test solution. With the run-in bearing in the jar, simultaneously start a timer and begin adding the synthetic sea water solution into the hole provided for this purpose in the bearing holder. Add the 100 mL of the solution within 20 +/- 3 s. When the timer shows 60 s, start withdrawing the solution. By 80 +/- 3 s, complete the withdrawal of 70 to 75 mL of the solution. Leave the remaining 25 to 30 mL of the solution in the jar.
10.9 Screw the cap on the jar and transfer to a dark oven essentially free from vibration for 24 h at 52 +/- 1°C.
NOTE 8 - Test Method D1743 calls for 48 h at 52 +/- 1°C.
10.10 Prepare three bearings for each grease sample to be tested at the percentage of dilute synthetic sea water of interest. Each group of three bearings is one test. See Table 1 for conversion.
11. Rating Procedure
11.1 Remove the bearing from the test jar and place the bearing cup in a 50/50 mixture by volume of isopropyl alcohol (Warning - see Note 1 and Note 3) and Stoddard solvent. The solvent mixture can be heated to facilitate the removal of the grease. Agitate vigorously to remove the grease. Repeat the rinsing using fresh solvent mixture or gently wipe the bearing with a clean cloth or tissue to ensure that traces of grease are removed.
11.2 Transfer the bearing cup from the solvent mixture and allow to dry on clean filter paper.
11.3 Examine the cup raceway for evidence of corrosion without the use of magnification (Section 5). Use only a pass or fail rating. Criteria for failure shall be the presence of any corrosion spot 1.0 mm or larger in the longest dimension. Ignore the number of spots.
NOTE 9 - Spots that are easily removed by rubbing lightly with soft tissue (alone or wetted with any solvent nonreactive to rust or steel at room temperature) shall not be considered as corrosion in the rating.
