D02.G0.07 - Research Techniques

SIGNIFICANCE AND USE
The quantitative determination of antioxidants in new greases measures the amount of the chemical compounds that were added to the base oil as protection against grease oxidation. For in-service oil greases, the voltammetric test method measures the amount of original (individual) antioxidants remaining after grease oxidation have reduced its concentration. Before making final judgment on the remaining useful life of the in-service grease, which might result in the replacement of the grease reservoir, it is advised to perform additional analytical techniques, such as Test Method D942 and D5483, which may be used to measure the remaining oxidative life of the used grease.
4.1.1 This test method is applicable to mineral oil-based and synthetic oil-based greases, based on all type of applied thickeners. This test method is applicable to greases containing at least one type of antioxidant. The presence of other types of additives like corrosion inhibitors or metal deactivators will not interfere with this test method.
SCOPE
1.1 This test method covers the voltammetric determination of antioxidants in new or in-service lubricating greases in concentrations from 0.0075 weight percent up to concentrations found in new greases by measuring the amount of current flow at a specified voltage in the produced voltammogram.
1.2 This test method is intended to monitor the antioxidant content in lubricating greases; it cannot be applied for lubricating greases that do not contain antioxidants.
1.3 This test method is designed to allow the user to monitor the antioxidant depletion rate of in-service greases through its life cycle as part of condition monitoring programs. This test method is performed in order to collect and trend early signs of deteriorating lubricant grease, and it may be used as a guide for the direction of any required maintenance activities. This will ensure a safe, reliable, and cost-effective operation of the monitored plant equipment.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
It is known that contamination by water can affect the shear stability of some greases in service. Both test procedures specified in this method are widely used to determine the wet shear stability of greases in service. Many grease specifications require these procedures as a wet shear stability test. No accurate correlation is established between the test results and wet shear stability of grease in actual service.
SCOPE
1.1 This test method covers two procedures for determining the shear stability of lubricating grease in the presence of water (wet shear stability) by a full scale grease worker or a roll stability test apparatus. Both procedures can be used to determine the relative wet shear stability of greases, but the results between procedures are not directly comparable. This test method is also known as the water stability test.
1.2 The values stated in SI units are to be regarded as the standard; The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.