Main Indicators and Meanings of Lubricating Grease

Dropping Point
The dropping point of lubricating grease heated from non-flowing state to flowing state under the specified heating condition is mainly decided by the type and content of densifier; using dropping point tester can roughly measure the maximum using temperature of lubricating grease.
 

Density
The density of lubricating grease refers to its hardness, shown by penetration. At 25°C, the depth the standard cone freely falls into lubricating grease in 5 seconds, unit 0.1mm.

Generally, the penetration is just working penetration, namely the penetration of lubricating grease sample measured after 60 times of cutting by perforated plate in the working container.

Oil Separating Degree
It refers to the capacity of keeping structure stability and preventing basic oil separating from lubricating grease.
Fill 10g grease in the cone stainless steel net, hang it in the breaker, measure the separated oil after specified time at specified temperature (generally 100°C, 21h), shown by %.
 

Mechanical Stability
It refers to the capacity of resisting density change under mechanical working condition, that is, the capacity of resisting mechanical shearing.

Extension Penetration
Penetration change or percent of change of lubricating grease sample measured after 100,000 times of working at 60 times/min in perforated plate working container.

Roller Stability
It refers to lubricating grease penetration change rate measured after 50g lubricating grease sample is rolled by 5kg roller in 2h (revolution 165r/min).
The smaller the penetration change or change rate of sheared lubricating grease, the better the mechanical stability.

Oxidization Stability
It refers to the oxidization resistance of lubricating grease in the process of the storage and use.
It is usually tested by oxygen bomb. Put lubricating grease sample into the stainless steel oxygen bomb, fill in 0.8MPa oxygen, measure the oxygen pressure reduction value and the acid value and free alkali change of the oxidized sample at specified temperature in the specified time (99°C, 100h). The smaller the oxygen reduction value or the acid value or the free alkali change of the oxidized sample, the better the oxidization stability.

Evaporation
It measures the performance change tendency of lubricating grease caused by evaporation and drying of the basic oil in the process of storage and use.
Put the steel container with 1mm grease sample in the special thermostat, keep a certain time at specified temperature (99~150°C, 22h), measure its lost quantity.
Copper sheet corrosion test assesses the corrosion probability of lubricating grease to copper. Put the polished copper sheet in specified dimension into lubricating grease sample, test the copper surface change after specified time at specified temperature (100°C, 24h).

Wear Resistance
Four-ball Testing: Testing the wear resistance of grease at extreme pressure.
Wear Resistance - Maximum nonseizure load: PB; wear scar diameter: D392N60min
Extreme Pressure Performance - Sintering load: PD; comprehensive wear value ZMZ
Ring Block Testing (Timken): Line contact sliding wear type, measuring bearing capacity and scratching resistance, shown by OK value.
 

Low Temperature Torque
It refers to the degree of preventing the rotation of low speed ball bearing when lubricating grease is used at low temperature. The value shows lubricating grease application performance at low temperature.
Start Torque - The maximum torque of the external ring rotated when the inner ring of the bearing begins rotating.
Running Torque - The average torque measured when the bearing is running stably (after 60min).
The start torque is far larger than the running torque, especially at low temperature. Torque unit: N.M.