Determination of Shear Stability of Grease

Overview

Grease is a semi-solid lubricant composed of base oil, thickener, additives, and other components. It is widely used for lubrication and protection of mechanical parts such as bearings and gears, effectively reducing friction and wear and preventing corrosion. Its mechanical stability directly affects the service effect and service life, while shear stability is the core indicator for evaluating the mechanical stability of grease, which can be intuitively reflected by the change in consistency after shearing.

Test Purpose

By determining the change in consistency of grease after a specified number of shearing cycles, this test evaluates its shear stability (the rationale for the test) and provides a basis for quality judgment and application selection of grease. This test is conducted in accordance with the requirements of GB/T269-91 "Test Method for Cone Penetration of Greases and Petrolatums", and the SH269 Grease Shear Tester is a special equipment designed and manufactured to meet this standard.

Test Samples and Instruments

Test Sample: Grease to be tested

Test Instruments:

SH269 Grease Shear Tester (for test preparation)

Auxiliary tools such as cleaning reagents and sample boxes

Operating Procedures

• Turn off the power of the instrument, load the grease to be tested into the sample box, and ensure that both sides of the sample are at the same horizontal height.
• Adjust the position of the piston rod orifice plate to maintain a 1~2mm gap between its bottom surface and the inner bottom surface of the grease container, then tighten the fastening screws below.
• Turn on the power, preset the number of shearing cycles through the counting display (adjustable arbitrarily within the range of 0~99999 cycles), and input information such as sample name and serial number.
• Click the "Start" button, and the instrument will automatically start shearing operation. The motor drives the reducer through the coupling, which in turn drives the eccentric mechanism to operate continuously at a rate of 60 cycles per minute.
• After reaching the preset number of shearing cycles, the instrument will automatically cut off the power and stop running without manual intervention; if continuous testing is required, directly click "Continue Testing" without turning off the power.

Data Analysis and Result Evaluation

Through precise detection by the SH269 Grease Shear Tester, after the test sample undergoes the specified number of shearing cycles, its working cone penetration extension value (unit: 0.1mm) meets the requirements of relevant quality standards, with errors controlled within the allowable range. This indicates that the grease has good shear stability and can meet the lubrication needs during mechanical operation.