ASTM D6138 Method for Corrosion-Preventive Properties of Lubricating Greases
ASTM D6138 Standard Test Method for Determination of Corrosion-Preventive Properties of Lubricating Greases Under Dynamic Wet Conditions (Emcor Test)
8. Preparation of Bearings
8.1 Examine the test bearings carefully and select only bearings that have outer rings and balls entirely free of corrosion. During the bearing preparation, handle the bearings with tongs or protective gloves. Do not touch the bearings with bare fingers at any time. Use two new bearings for each grease being tested.
8.2 Number bearings on the outside diameter of the outer ring, but do not use chemical etching. One method to number the bearings is with an electric pen, which should be grounded on the outer ring surface being marked.
8.3 Wash the selected bearings thoroughly in hot (50 to 65°C) mineral spirits (Warning - see 7.8) to remove the rust preventive. To ensure complete removal, subject the bearing to a second wash in fresh hot mineral spirits. (Warning - The washing temperatures specified are considerably above the flash point of the solvent. Accordingly, the washing operation should be carried out in a well-ventilated hood where no ignition source is present.)
8.4 Transfer bearings to the solvent rinse solution (Warning - see 7.7.3) to remove any mineral spirits which may be present. Rinse each bearing and slowly rotate one ring relative to the other ring in fresh hot (65 more or less 5°C) solvent rinse solution. Fresh rinse solution is used to avoid the selective evaporation of the components at the rinse temperature.
NOTE 2 - Care must be taken when handling bearings in the hot rinse solution to avoid burns. Tongs and heat resistant gloves are recommended.
8.5 Remove each bearing from the solvent rinse solution and place on filter paper to drain. After draining, dry the bearing in an oven at 90 more or less 2°C for 15 to 30 min.
8.6 Permit the bearing to cool to room temperature and reexamine the surfaces to ensure that corrosion-free bearings have been selected. (Exercise care when handling the bearing to avoid rotating one ring relative to the other ring after cleaning and drying.)
8.6.1 Inspect the outer ring tracks. (Fig. 1 illustrates the area to be inspected.) If etch spots or corrosion are evident, reject the bearing. A dentist’s mirror can be helpful for inspection purposes.
