To lubricate heavy equipment, certain extreme pressure or antiwear additives are added to the grease to improve the extreme pressure and antiwear properties of the grease. Extreme pressure and antiwear properties of grease are very important indicators. If the extreme pressure and anti-wear properties are not good, it will cause serious wear and tear of the equipment, and equipment damage will lead to equipment accidents.

　　There are four methods for the determination of extreme pressure and anti-wear properties:

　　The Timken test

　　The test was conducted on a Timken test machine. Grease is added between the friction pair of the metal ring and the metal block with a certain flow and a certain load and speed. After a period of operation, observe the wear marks on the metal block to determine the extreme pressure properties of the grease, expressed as an OK value.

　　1.1 Study the ability of greases to resist loads in linear contact.

　　1.2 Test method: SH/T 0203

　　2. Anti-wear properties (SH/T 0204)

　　On a four-ball long-grinding tester, under the specified load conditions, the upper steel ball rotates relative to the lower three static steel balls whose surface is covered with the sample. After the test, the wear trace diameters of the lower three steel balls were measured. The wear scar diameter is used to judge the antiwear performance of the grease.

　　Significance: This method is used to determine the relative wear performance of different greases under test conditions and cannot differentiate between extreme pressure and non-extreme pressure greases.

　　3. four ball test (GB/T 3142)

　　The four-ball test is to add grease to the ball box, and under a specified load, the upper steel ball rotates at a certain speed relative to the three static steel balls below. After a period of time, measure the diameter of the wear track to judge the extreme pressure performance of the grease.

　　This method has three representations: PB value, PD value, ZMZ value

　　PB value: refers to the maximum load that will not occur under test conditions, expressed in N.

　　PD value: It is the minimum load for sintering the rotating ball and the three fixed balls under the test conditions, expressed in N. ZMZ value: An indicator of a grease's ability to resist extreme pressure under an applied load. During the test, the load was gradually applied to the three static steel balls at 0.1 log unit intervals, and the test results of the first ten sintering loads were used for the calculation.

　　ZMZ value, represented by N.

　　4. four ball test (GB/T12583)

　　This method has three representation methods: PB value, PD value, LWI value

　　LWI value: Refers to the ultimate pressure capability index of the sealing grease under the ultimate load to minimize the applied load. Under this test condition, it is equal to the average of the corrected loads measured by applying a 0.1 log unit load on the three static balls prior to the sintering point and performing ten tests.