3. Terminology
3.1 Definitions
3.1.1 consistency, n-of lubricating grease, the degree of resistance to movement under stress.
3.1.1.1 Discussion - The term consistency is used somewhat synonymously with penetration. Generally, consistency refers to the worked penetration of a grease.
3.1.2 lubricant, n-any material interposed between two surfaces that reduces the friction or wear between them.
3.1.3 lubricating grease, n-a semi-fluid to solid product of a dispersion of a thickener in a liquid lubricant.
3.1.3.1 Discussion - The dispersion of the thickener forms a two-phase system and immobilizes the liquid lubricant by surface tension and other physical forces. Other ingredients are commonly included to impart special properties.
3.1.4 penetrometer, n-an instrument that measures the consistency or hardness of semiliquid to semisolid materials by measuring the depth to which a specified cone or needle under a given force falls into the material.
3.1.4.1 Discussion - In this test method, either a standard penetrometer 6.2 or an optional penetrometer cone A1.3 can be used to determine the consistency of lubricating greases. The penetration force is determined by the mass of the cone and the shaft.
3.1.5 thickener, n-in lubricating grease, a substance composed of finely divided particles dispersed in a liquid lubricant to form the product's structure.
3.1.5.1 Discussion - The thickener can be fibers (such as various metallic soaps) or plates or spheres (such as certain non-soap thickeners) which are insoluble or, at most, only very slightly soluble in the liquid lubricant. The general requirements are that the solid particles be extremely small, uniformly dispersed, and capable of forming a relatively stable, gel-like structure with the liquid lubricant.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 block penetration, n-of lubricating grease, the penetration at 25°C (77°F) determined on the freshly prepared face of a cube cut from a sample that is sufficiently hard to hold its shape.
3.2.2 penetration, n-of lubricating grease, the depth that the standard cone (see A1.1), enters the sample when released to fall under its own weight for 5 s.
3.2.3 penetrometer, n-an instrument (see Fig. 1) designed to measure the depth to which the standard cone falls into the grease.
3.2.4 prolonged worked penetration, n-of lubricating grease, the penetration of a sample after it has been worked more than 60 double strokes in a standard grease worker at a temperature of 15 to 30°C (59 to 86°F).
3.2.4.1 Discussion - After the prescribed number of double strokes, the worker and contents are brought to 25°C (77°F), worked an additional 60 double strokes, and penetrated without delay.
3.2.5 unworked penetration, n-of lubricating grease, the penetration at 25°C (77°F) of a sample that has received only minimum disturbance in transferring to a grease worker cup or dimensionally equivalent rigid container.
3.2.6 worked penetration, n-of lubricating grease, the penetration at 25°C (77°F), without delay, of a sample after 60 double strokes in a standard grease worker.
3.2.7 working, n-of lubricating grease, the subjection of a sample to the shearing action of the standard grease worker.
