Tutorial 2: How to Conduct Friction and Wear Simulation Tests

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Selection of custom test equipment (Part 2): Whether it comes to friction and wear simulation tests for oils (including cutting fluids, emulsions, bio-oils, etc.) or materials, there are always custom test requirements, especially for those friction and wear simulation tests related to materials for which no standards exist. 1. Lubrication performance of oils: For non-standard tests related to oils (including cutting fluids, emulsions, bio-oils, etc.), options include four-ball friction and wear testing machines, diesel lubrication performance evaluation machines, or aviation fuel lubrication performance evaluation machines. On the same device, select the same test conditions and measure the same indicators to conduct comparative tests ； Reciprocating or rotary material wear testing machines can also be selected. Within the limits permitted by the equipment, using the same materials and the same testing conditions but with different oils as the medium, the lubricating performance of the oils is evaluated by testing the degree of material wear and the friction coefficient during the test. 2. Metal and non-metal materials: The non-standard tests related to materials (including metal and non-metal materials) are relatively more complex than those related to oils. Currently, there are no unified standard methods for friction and wear simulation tests on many materials. For experiments without unified standards, the selection of equipment and experimental conditions must be determined based on one’s research objectives and topics, taking into account the actual properties of the materials as well. If simulating actual operating conditions is required, the type of friction and wear simulation test must be selected based on the specific working environment and conditions of the material under study. For example, whether the specific motion pattern is rotational or reciprocating ； Is the friction mode point contact, line contact, or surface contact? ； Is the working environment oil drip lubrication, oil immersion lubrication, boundary lubrication, or dry friction? ； Whether the test medium is water, acidic solutions, mud, special solutions, or solid abrasives; whether the working atmosphere should be air, inert gases such as N2, CO2, He, etc., or a vacuum environment; and what the working temperature is, whether it is room temperature, high temperature, or low temperature. In addition, it is also necessary to take into account the working pressure (load) that the material itself can withstand, the speed, and the range permitted by the equipment. All factors related to the comprehensive tests are considered to select or customize appropriate equipment and test conditions for friction and wear simulation tests. If it is a material comparison test, the factors to consider are relatively simpler. On the premise of simple sample preparation and guaranteed accuracy, it is sufficient to select consistent testing conditions within the range that the sample material can withstand on the same equipment, as long as those conditions are within the limits permitted by the equipment. Options include the MMW-1A vertical universal friction and wear testing machine, MRH-3 high-speed ring-block friction and wear testing machine, MDW-02 mechanical reciprocating friction and wear testing machine, MMU-5G high-temperature friction and wear testing machine for material end faces, MMQ-02G high-temperature friction and wear testing machine, MMS-2A microcomputer-controlled friction and wear testing machine, and the MRH-1 ring-block friction and wear testing machine, among others. In addition, friction and wear testing machines designed for measuring oil-related parameters can also be used, such as four-ball friction and wear testing machines and diesel lubricity evaluation testing machines. The materials under study can be processed into test specimens, and the same oil can be used as the testing medium; by setting identical testing conditions, comparative tests of the materials can be conducted within the limits permitted by the equipment. In summary, whether it is standard tests or non-standard tests, whether they are tests related to oils or materials. To conduct friction and wear simulation tests properly and effectively, the proper selection of equipment is the first step toward carrying out such tests successfully, and it also forms the basis for their proper and effective execution.