Dropping point: Dropping point is an
indicator of the heat resistance of grease. As grease
temperature rises, penetration increases until the grease
liquefies and the desired consistency is lost. Dropping
point is the temperature at which a grease becomes fluid
enough to drip. The dropping point indicates the upper
temperature limit at which a grease retains its structure,
not the maximum temperature at which a grease may be used.
few greases have the ability to regain their original
structure after cooling down from the dropping point.
ASTM D2265 - 06(2014) Standard Test Method for Dropping Point of Lubricating Grease Over Wide Temperature Range
The dropping point is useful to assist in identifying the grease as to type and for establishing and maintaining bench marks for quality control. The results are to be considered to have only limited significance with respect to service performance because dropping point is a static test.
Cooperative testing indicates that, in general, dropping points by Test Method D2265 and Test Method D566 are in agreement up to 260°C. In cases where results differ, there is no known significance. However, agreement between the manufacturer and purchaser as to test method used is advisable.
ASTM D-2265 Grease Dropping Point