Shear stability of lubricating grease refers to the ability of grease to resist consistency change under certain conditions of mechanical shearing force, and is an important index to evaluate the mechanical stability and service life of lubricating grease. The shear stability is related to the fiber structure strength of the grease and the adsorption force between the fibers. The degree of change of the structural system of the grease subjected to the shear force is expressed by the consistency of the grease, that is, the structure of the grease is subjected to mechanical shearing. The value of the change in penetration before and after the force is applied. The change in the working penetration of the grease after the extended shear test work can be considered as the shear stability measured under the test conditions. For the test method, see GB/T269 "Test Method for Shear Stability of Grease", which is equivalent to ISO2137-1983.

    Analytical equipment and materials: Penetration tester and full-size grease working device in accordance with GB/T269; grease shearing tester as shown in the figure on the right; constant temperature water bath that can be maintained at 25℃+-0.5℃; 25°C calibrated thermometer; stopwatch, etc.

    Test steps: keep the temperature at 15~30℃r, put the grease sample into the grease cup of the working device, no need to further control the temperature of the grease working device; assemble the working device and install the working device on the shear testing machine, test The sample reciprocates up and down on the shear testing machine at a rate of 60 times per minute according to the specified or agreed times; after completing the work on the sample, immediately place the grease working device in a constant temperature water bath of 25℃+-0.5℃ for 1.5H ; Then take out the working device and reciprocate 60 times within about 1 minute; then measure the penetration value of the grease according to the test method conditions, and use the penetration value of the 60 working times before the shear test and the after shear test (10,000). The difference in the penetration of 60 times or 100,000 times of work indicates the shear stability of the grease. The smaller the difference in penetration, the better the shear stability of the grease.