Heat treatment is an important basic technology in the machinery industry. Usually, important mechanical parts and tools such as shafts, bearings, gears, connecting rods, etc. are heat-treated, and mechanical parts can be made by proper heat treatment and proper heat treatment. It has doubled the service life of the tool and even increased it by a dozen times. It achieves the goal of “doing a good heat treatment and a few parts at the top†and receiving twice the result with half the effort. Conventional heat treatment, in terms of the main control parameters, is mostly heat treatment of two parameters of temperature and temperature under normal pressure; in terms of process mode, it is mostly a single heat treatment. The effect of such heat treatment can only be singular. To this end, we must vigorously develop multi-parameter heat treatment and composite heat treatment processes. Multi-parameter heat treatment Vacuum heat treatment: This is a multi-parameter heat treatment with additional pressure. It has the advantages of no oxidation, no decarburization, bright surface of the workpiece, small deformation, no pollution, energy saving, high degree of automation, wide application range, etc. It is one of the fastest growing new heat treatment technologies in recent years, especially in the surface of materials. Great progress has been made in the modification, and many newly developed advanced heat treatment technologies, such as vacuum high pressure gas quenching and vacuum chemical heat treatment, also need to be carried out under vacuum. The vacuum heat treatment technology can greatly improve the quality and service life of structural materials and tools, especially for the heat treatment of some precision parts. In industrialized countries, the proportion of vacuum heat treatment has reached about 20%, while China currently has about 1200 vacuum heat treatment furnaces, accounting for about 1% of the total number of heat treatment furnaces, which is very different from foreign countries. It is expected that with the advancement of technology in the heat treatment industry and the increasing requirements for the quality of heat-treated workpieces, vacuum heat treatment will have a great development. Chemical heat treatment: This is a multi-parameter heat treatment of additional components. Ordinary chemical heat treatments, such as carburizing, carbonitriding, and carbonitriding, are multi-parameter heat treatments with additional one-component, two-component, and three-component. In recent years, many new chemical heat treatments using new technologies, such as vacuum chemical heat treatment, fluidized bed chemical heat treatment, ion metal infiltration, ion implantation, laser surface alloying, etc., have been developed to improve wear resistance and corrosion resistance of workpieces. Wait for performance. The application of rare earth in chemical heat treatment (ie, co-infiltration with rare earth) can significantly improve the seepage speed, shorten the treatment cycle, and improve the wear resistance and corrosion resistance of the layer. This is a major feature of China. In addition, solid solution chemical heat treatment is also a noteworthy trend. The Inner Mongolia Agricultural Machinery Research Institute Huang Jianhong et al. developed a nitrogen-containing martensite treatment (N*M treatment) process, which is the first to obtain solid solution N nitrogen. The nitriding process for the purpose of martensite has been successfully applied to the production of shearing blades. (3) Deformation heat treatment: This is a multi-parameter heat treatment with additional stress. The combination of pressure processing and heat treatment combines deformation strengthening and phase transformation strengthening to achieve the dual purpose of forming and composite strengthening. The deformation heat treatment can improve the comprehensive mechanical properties of the material, and can simplify the process, utilize waste heat, save energy and material consumption, and have significant economic benefits. Deformation heat treatment is widely used, from structural steel to bearing steel to high speed steel. At present, the most widely used in the industry is forging residual heat quenching and controlled rolling. The United States uses controlled rolling to produce high-hardness armor plates that increase the resistance to elastic. China's weapon industry system has carried out experimental research on artillery and shell parts hot die forging heat quenching, barrel rotating precision forging heat treatment, gun steel core oblique rolling residual heat quenching, etc., and achieved good results. Composite heat treatment Composite heat treatment is to combine two or more heat treatment processes, or to combine heat treatment with other processing techniques, so that the combined effects of several processes involved in the combination can be obtained, the workpiece can obtain excellent performance, and energy can be saved and reduced. Cost and increase production efficiency. Such as nitriding and high-frequency quenching compound, quenching and sulphur composite, boronizing and powder metallurgy sintering process. The aforementioned forging waste heat quenching and controlled rolling are also composite heat treatments, which are respectively a combination of forging and heat treatment, rolling and heat treatment. There are also some new composite surface treatment technologies, such as laser heating and chemical vapor deposition (CVD), ion implantation and physical vapor deposition (PVD), physical chemical vapor deposition (PCVD), etc., which have significant surface modification effects. Applications at home and abroad are also increasing. It should be pointed out that the composite heat treatment is not a simple superposition of several single heat treatment processes, but it is organically combined according to the requirements of the performance of the workpiece and the characteristics of each heat treatment process, so as to achieve the purpose of complementing each other and complementing each other. . For example, since the processing temperatures of various heat treatment processes are different, it is necessary to consider the order of the heat treatment processes participating in the combination to avoid the offsetting effect of the subsequent processes on the previous processes. Heat treatment is of great significance for giving full play to the performance potential of metal materials, improving the intrinsic quality of products, saving materials, reducing energy consumption, extending product life and improving economic efficiency.