Because the final transformation temperature of martensite in most alloy steels is below zero, the properties of materials can not be fully exploited by general heat treatment. For some materials, the end point of martensite transformation is even low temperature – 100 ℃, so only ultra-low temperature treatment can fully tap the potential of materials. For quenched alloy steel, the volume shrinkage of martensite matrix will produce great micro stress in the matrix and increase the matrix defects; after ultra-low temperature and cryogenic treatment, the content of retained austenite can be purposefully controlled and the nano carbide particles scattered in the matrix can be found, which can enhance the wear resistance, strength and toughness of the workpiece, thus improving the service life of the workpiece. Just as high temperature superconductor will show zero resistance at ultra-low temperature, so do cemented carbide and alloy steel. A large number of nanoscale carbide particles and substructures will appear in the matrix structure, which can significantly improve the strength and toughness of the workpiece. At the same time, the diffusion ability of carbon atoms is enhanced at a sharp low temperature, and a large number of nanoscale particle structures can be precipitated from the interior of cemented carbide and alloy steel by ultra-low temperature treatment In addition, the Ultra-fine Carbides which are consistent with the matrix can be re precipitated in the defects of the products, so as to improve the matrix defects. On the one hand, it can effectively improve the wear resistance, on the other hand, it can effectively improve the strength, hardness, red hardness, toughness and cutting performance.
The outstanding advantages of this technology are as follows:
1) It can fully tap the potential of materials, and increase the service life of materials by 1-8 times
2) Can make the size of the workpiece stable, no bending, no deformation
3) It can increase the wear resistance and corrosion resistance of the material
4) It can reduce the residual stress inside the material
5) It can strengthen the whole material and improve the strength and hardness of the material
6) The internal structure of the material becomes more uniform;
7) It can improve the toughness and impact toughness of the tool
8) Reduce and shut down maintenance and improve labor productivity
9) No damage to product appearance and color