Manufacturing method of ultra low temperature and cryogenic treatment equipment

At present, the mainstream technology of modification and strengthening treatment of formed metal materials, tools, moulds and accessories is coating. The disadvantages of coating technology are surface modification, high cost, long delivery cycle, complex technology and large investment, and it is powerless for non-standard parts, special-shaped parts and large workpieces.

Cryogenic processing technology is a new technology to improve the performance of metal workpiece, which is the most effective and economic technology. It can make up for the failure of coating technology.

The mechanism of cryogenic treatment technology is to use refrigerant as cooling medium to continue the cooling process of quenched metal materials to achieve a temperature far lower than the room temperature (- 196 ° C), so as to improve the properties of metal materials. In the process of cryogenic treatment, a large amount of retained austenite transforms into martensite, especially the supersaturated metastable martensite will decrease the saturation, precipitate and disperse, and the micro stress will decrease during the process from – 196℃ to room temperature. The fine and dispersed carbides can block the dislocation movement and strengthen the matrix structure. At the same time, the ultra-fine carbide particles are evenly distributed on the martensite matrix after precipitation, which weakens the degree of grain boundary segregation and plays the role of grain boundary strengthening, so as to improve the performance of tools and dies, and significantly improve the hardness, impact toughness and wear resistance.

For deep cryogenic treatment of cemented carbide, the internal stress of cemented carbide can be adjusted reversely, that is, the tensile stress in cobalt can be reduced, and even the appropriate compressive stress can be adjusted to increase the resistance of microcracks. Therefore, the generation of microcracks can be reduced and the resistance to microcracks can be improved The results show that the fatigue strength, toughness and the adhesion of cobalt to tungsten carbide are increased, the stripping of tungsten carbide is reduced and the wear resistance is improved. The improvement effect of cryogenic technology is not limited to the surface of the workpiece. It penetrates into the interior of the workpiece, reflecting the overall effect. Therefore, the workpiece can be reground and used repeatedly. Moreover, it can reduce the quenching stress and enhance the dimensional stability of the workpiece.

The existing cryogenic treatment is to soak the metal workpiece directly in the container containing liquid nitrogen, or spray the liquid nitrogen on the surface of the metal workpiece, which is easy to cause the micro crack and surface corrosion of the workpiece due to the large thermal impact force, and can not control the temperature change of the metal workpiece, resulting in the destruction of the structure of the workpiece. In addition, most of the existing cryogenic treatment equipment do not solve the problems of high energy consumption and high cost in the treatment process. Industrial refrigerator can solve all the above problems, low power consumption, no use of gas, no leakage, can solve the problem of storage.

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