Vacuum heat treatment technology is a new type of heat treatment technology developed in recent years. Its characteristics exactly what are needed in the manufacture of molds, such as preventing thermal oxidation and decarburization, vacuum degassing or degassing, eliminating hydrogen embrittlement, thus improving the plasticity, toughness, and fatigue strength of materials (parts). The slow heating of the vacuum and small temperature difference between the inside and outside of the part decide that the deformation of the parts in the vacuum heat treatment process is small.
According to the different cooling medium used, vacuum quenching can be divided into vacuum oil quenching, vacuum gas quenching, and vacuum water quenching and vacuum nitrate salt isothermal quenching. The main application of vacuum heat treatment is vacuum oil quenching, vacuum gas quenching and vacuum tempering. In order to maintain the excellent characteristics of the vacuum heating of the workpiece (such as the die), the selection and formulation of the coolant and cooling process are very important. The process of die quenching is mainly used for oil cooling and gas cooling.
For the die surface, which is no longer machined after heat treatment, the vacuum tempering, especially the vacuum quenched workpiece (die) can be used to improve the mechanical properties related to the surface quality, such as fatigue property, surface brightness, corrosion resistance, etc.
The successful development and application of computer simulation technology in heat treatment process (including tissue simulation and performance prediction technology) makes the intelligent heat treatment of the mold possible. Because of the characteristics of small batches (even single pieces) and many varieties of molds, high requirements on heat treatment performance and features that do not allow the waste products, the intelligent heat treatment of molds becomes necessary.
The intelligent heat treatment of the moulds includes: the structure of the mold, the material, the requirement of the heat treatment performance; the computer simulation of the temperature field and the distribution of the stress field during the heating process of the die; the simulation of the heating and cooling process; the formulation of the quenching process; and the automatic control technology of the heat treatment equipment.
Foreign developed industrial countries, such as the United States and Japan, have carried out technical research and development in vacuum high-pressure gas quenching, and mainly aiming at moulds.