【 Building materials network 】Plasma with rapid development and wide industrial application heat treatment The method is plasma chemical heat treatment. Compared with conventional chemical heat treatment, plasma chemical heat treatment has the characteristics of high quality, * *, low consumption, clean, pollution-free, etc. However, this technology is used for small molds and other Small parts (such as Bolt 、 Nut , chain, etc.), the charging is troublesome, and the quality of the infiltration layer is difficult to control. Moreover, it is not easy to uniformly control the temperature of workpieces when mixing workpieces of different shapes and sizes in the same furnace.
　　
1.1 Ion carburizing
　　
Ion carburizing, also known as glow carburizing [l0-11]. Carburizing is a kind of heat treatment method that heats the low carbon steel or low carbon alloy steel parent material with low price, good formability and ductility in the carbon based atmosphere to make active carbon penetrate into the parent material to form a strong, tough and wear-resistant surface. Ion carburizing is that activated carbon is obtained by ionization of hydrocarbon gas in vacuum plasma zone through DC glow discharge, and its principle is similar to that of ion nitriding.
　　
In China, the ion carburizing process has been successfully applied to the molds of automobile, aviation, nuclear industry, etc. Technical key of ion carburizing key It is the quality control and equipment design of infiltration layer. During ion carburizing, the preset carbon content on the surface of the die workpiece can be controlled by adjusting the carbon flux and carburizing time. Carbon flux is a function of gas composition, pressure, gas flow, ion current density and carburizing temperature. In industrial production, during ion carburizing, the mathematical model of carbon diffusion and transmission can be used to control the whole process by microcomputer through current density sensor, so as to obtain the predetermined surface carbon content, carbon distribution and carburizing depth. However, the temperature of ion carburizing process is high (850~980 ℃) Power Supply High power, easy to change from glow discharge to arc discharge, which makes the process unstable and the equipment complex. At present, the gas carburizing and vacuum carburizing processes commonly used in industrial dies are mature and stable in quality, which can better meet the needs of industrial dies. Compared with traditional carburizing, ion carburizing has the following advantages: high carburizing efficiency, good surface quality, uniform carburizing layer distribution, small deformation, small environmental pollution, easy to realize automatic control in the process, and can also handle deep blind holes. In the mold industry, ion carburizing technology has been applied to Plastic mold It is widely used in. At present, more than 80% of surface hardening is carburizing treatment. Therefore, ion carburizing has broad prospects for development.
　 　
1.2 Ion nitriding
　　
Ion nitriding is a widely used and mature ion heat treatment process in industry at present [1-3]. The process is easy to obtain pure diffusion layer, single phase, compound layer, etc. by adjusting process parameters (such as voltage, current, furnace gas pressure, temperature, time and working gas composition). The key technology of ion nitriding is how to reasonably select the process parameters according to its characteristics and the service conditions of the relevant dies, and then obtain the desired better nitriding layer.
　　
1.3 Ionic carbonitriding
　　
Ion carburizing and nitriding technology is realized by the decomposition of furnace gas active components C3H8 and NH3 on the steel surface, and the precipitated active atoms C and N are absorbed on the surface and diffused to the interior of the matrix [2,4]. It is also called ion soft nitriding, which is developed from salt bath and gas soft nitriding. The operation method of ion carburizing and nitriding is basically the same as that of ion nitriding, but the working gas composition is different. In addition to slow cooling under vacuum conditions, the cooling method can also be oil quenching or high-pressure gas quenching. Ionic carbonitriding has the advantages of short time, high benefit, thicker compound layer, and excellent wear resistance, scuffing resistance and fatigue resistance. Compared with the traditional process, the ion carbonitriding technology applied to molds not only has the advantages of good quality of carburizing layer and easy control of phase composition, but also is * *, clean and energy-saving. The process has strong market competitiveness.