With the continuous development of low temperature technology, the application of low temperature has penetrated into various fields of the national economy, including natural gas liquefaction, nuclear fusion, superconductivity, hydrogen energy utilization, aerospace, biomedical, food industry, etc. at the same time, the application of low temperature in the metal material industry and high-end machinery manufacturing field has been increasingly valued, On this basis, the material cryogenic treatment modification technology has become the focus of scholars and material production and processing industry.
Macro effect of cryogenic treatment of industrial freezer
(1) In the mechanical industry and equipment manufacturing industry, the wear resistance of parts and components has a great impact on the performance and service life of mechanical equipment. In the actual production process, the most traditional way to improve the wear resistance of parts and components is surface treatment (carburizing, nitriding, electroplating, laser cladding, etc.), however, The appearance of cryogenic treatment of industrial freezers is to improve the wear resistance of steel materials.
It is generally believed that the mechanism of improving the wear resistance of iron and steel materials by cryogenic treatment for industrial freezers is due to the decomposition of retained austenite and the precipitation of ultrafine carbide particles, especially the carbide particles have a great influence on the wear resistance.
In addition to iron and steel materials, the wear resistance of non-ferrous metals and even non-metallic materials is also gradually concerned. It is found that the wear resistance of industrial freezers for magnesium alloy is significantly improved after cryogenic treatment. The cryogenic treatment of industrial freezers changes the stress state of cemented carbide, At the same time, some martensitic phases in the matrix are transformed from α – CO with face centered cubic structure to ε – CO with dense hexagonal structure, which improves the wear resistance of the cemented carbide. The main reason is that the crystallinity of the polymer paper model is improved by the cryogenic treatment. It can be seen that the cryogenic treatment of the industrial ice box has certain effect on the improvement of the wear resistance of different kinds of materials,
(2) In addition to improving the wear resistance, the mechanical properties of materials, such as strength, plasticity, toughness and fatigue, are also improved by cryogenic treatment. The transformation of retained austenite into martensite can improve the strength of the material by the cryogenic treatment of industrial freezer. Generally, the cryogenic treatment of industrial freezer can improve the wear resistance of steel material and the strength of the material at the same time, at least there will be no obvious decline, The effect of cryogenic treatment on the plasticity of steel is relatively small. The transformation of retained austenite to martensite in industrial freezer will reduce the toughness, but in most cases, the cryogenic treatment can improve the toughness of steel
(3) The influence of cryogenic treatment on dimensional stability of industrial freezers the so-called dimensional stability problem refers to the ability of materials to resist permanent deformation under the working environment conditions without external force or under the stress below the elastic limit after heat treatment and processing, and the ability to keep the size unchanged during processing, The spontaneous change of metal material size is the result of the following two factors: ① the instability of material phase and structure; ② the residual internal stress and its relaxation in parts during various hot and cold processing processes and mechanical assembly operations.