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The test grease is inserted into the container and the plunger is stroked 60 times while the test apparatus and grease are maintained at a temperature of 25 °C. Once worked, the grease is placed in a penetration test apparatus. This apparatus consists of a container, a specially-configured cone and a dial indicator. The container is filled ...
Grease generally consists of a soap emulsified with mineral or vegetable oil. A common feature of greases is that they possess high initial viscosities , which upon the application of shear, drop to give the effect of an oil-lubricated bearing of approximately the same viscosity as the base oil used in the grease.
The measure of the consistency of a lubricating grease is commonly expressed by its NLGI consistency number, defined by the NLGI in the “standard classification of lubricating grease”. The NLGI consistency number is used in several standards: ASTM D4950 , SAE J310 and ISO 6743-9 “lubricants, industrial oils and related products (class L ...
In 1921, US government lubrication specifications were drawn up to facilitate the purchase of oil by the government. [9] Representatives from the government, SAE, and the American Petroleum Institute met in 1922, [13] resulting in SAE adopting a specification for 10 grades of oil in March 1923. [11] [9] This specification was not adopted for ...
The contact area is flooded with the lubricant or grease being tested. The Timken OK Load is the highest standard load at which the spinning bearing race produces no scouring mark on the test block, but only a uniform wear scar. [1] Timken OK Loads are listed on grease and oil property charts and are part of many specifications.
The dropping point of a lubricating grease is an indication of the heat resistance of the grease and is the temperature at which it passes from a semi-solid to a liquid state under specific test conditions. It is dependent on the type of thickener used and the cohesiveness of the oil and thickener of a grease. [1]
If the viscosity, density, relative density (specific gravity) and refractive index [7] for a mineral oil is determined, the viscosity-gravity constant (VGC) and refractivity intercept (ri) can be calculated. Using the given values, the percent carbons (%CA, %CN, %CP) can be derived from a correlation chart, the ASTM D2140 method. [8]
The oil and the oil filter need to be periodically replaced; the process is called an oil change. While there is an entire industry surrounding regular oil changes and maintenance, an oil change is a relatively simple car maintenance operation that many car owners can do themselves.