1. Age Hardening
The phenomenon that the consistency of grease increases with storage time (hardening).
2. Apparent viscosity
The ratio of the shear stress to the deceleration of a non-Newtonian fluid calculated in accordance with the Poiseuille equation in Poise. The apparent viscosity of most greases varies with shear rate and temperature, so the measured value deceleration and temperature must be reported. Apparent viscosity, some also translated as "similar viscosity."
Use only visual inspection methods to see the characteristics of the grease. This term usually includes: Bulk Appearance, Texture, Bloom, Color, and Luster.
The overall appearance refers to the appearance of the unstirred fat when viewed in an opaque container. The overall appearance should be described in terms of: Smooth, Rough, Grainy, Cracked, and Bleeding.
Texture refers to the properties of the grease observed when a small amount of grease is pressed together and then slowly separated. The texture should be described by the following terms: Brittle, Buttery, Long fiber, Resilient, Stringy, etc.
Fluorescence refers to the color of the surface of the fat (usually blue or green) as observed by sunlight reflection from a direction of about 45 ° from the surface of the fat. Fluorescence is related to the ultraviolet light absorbed in the oil and may not be visible when viewed under an artificial light source.
The color of the grease is usually the hue and intensity that the grease exhibits when viewed under conditions that eliminate fluorescence. The color of the grease is described by its main color, such as amber, brown, etc., and some restrictive adjectives such as "light", "medium", "dark", etc. are used to describe the intensity of the color. Some fats are added with dyes, which can be described by green, red, blue and so on.
Gloss refers to the intensity of the light reflected by the fat surface. It is often described in the following terms: bright, dull, etc.
Consistency refers to the degree to which plastic materials resist deformation under the action of external forces. Just as viscosity is a characteristic of fluidity, consistency is a characteristic of plasticity. Consistency is usually expressed in terms of penetration.
It indicates how easy it is for grease to reach the point of use from its container, such as a storage tank. This concept is often used when discussing concentrated lubrication of grease. Distributability includes pumpability and feedability. Pumpability is usually measured by the apparent viscosity at a medium shear rate. The feed capacity is the ability of the grease to flow to the suction pipe of the distribution pump at a speed at least equal to the pump's delivery capacity.