Bimetallic saw band is a kind of composite material formed by electron beam welding of high-speed tool steel and high-strength hot working alloy steel of back material, which is processed by multiple processes. Due to the characteristics of composite materials, the two materials have different optimal quenching and tempering process parameters, so it is impossible to separate the teeth from the base material during heat treatment, and can not give full play to the potential of these two materials, resulting in tooth and substrate The problem of asynchronous failure affects the service life of bimetal saw belt. Cemented carbide is composed of a variety of superhard materials and binders through high temperature and high pressure to form a whole. There must be some loose structure in the cemented carbide, which is fragile and easy to collapse. The internal crystal of each unit of the material still has the potential of further refining.
The tempering process temperature is less than 530 ℃, because the final transformation temperature of martensite is below zero in most alloy steels during heat treatment, the properties of materials cannot 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. After quenching, the volume shrinkage of martensite matrix of alloy steel will produce great micro stress in the matrix, which will cause the increase of matrix defects; after ultra-low temperature and cryogenic treatment, the content of retained austenite can be purposefully controlled and nano carbon particles can be distributed in the matrix, which can enhance the wear resistance, strength and toughness of the workpiece, so as to improve the service life of the workpiece. Just as high temperature superconductor will show zero resistance at ultra-low temperature, there will be a large number of nano carbide particles and substructures in the matrix structure of cemented carbide and alloy steel, which can significantly improve the strength and toughness of the workpiece. At the same time, the diffusion ability of carbon atom is enhanced under the sharp low temperature. A large number of nano particles can be precipitated from the inner of the alloy by ultra-low temperature treatment, and the crystal can be refined. The ultra-fine carbide which is consistent with the matrix can be re precipitated in the crystal defects and other parts, so that the matrix defects can be improved. On the one hand, the wear resistance can be effectively improved, on the other hand, it can be effectively improved Degree, hardness, red hardness, toughness, improve cutting performance.
The outstanding advantages of this technology are as follows:
- 1) it can fully tap the potential of materials, and can increase the service life of materials by 1-8 times;
- 2) it can make the size of workpieces stable without bending and deformation;
- 3) it can increase the wear resistance and corrosion resistance of materials;
- 4) it can reduce the internal residual stress of materials;
- 5) it can strengthen the whole material and improve the strength and hardness of materials;
- 6) make the internal structure of materials become more and more It can improve the toughness and impact toughness of tools, reduce machine downtime and improve labor productivity, and prevent damage to product appearance and color.
To sum up, the invention adopts quenching, tempering, cryogenic treatment and tempering technology, which can not only improve the cutting ability and wear resistance of the existing saw band tooth, but also significantly improve the fatigue resistance of the base material of the bimetal saw band, significantly improve the service life of the bimetal saw band and hard alloy, and the process method is simple, the operation is convenient, and the production of the mechanical industry is reduced The cost has significant economic and social benefits and has the prospect of industrial application.