Vacuum heat treatment technology is a new type of heat treatment technology developed in recent years. It has the characteristics that are urgently needed in die-casting mold manufacturing, such as preventing heating oxidation and non decarburization, vacuum degassing or degassing, eliminating hydrogen embrittlement, so as to improve the plasticity, toughness and fatigue strength of mold parts. Due to the slow vacuum heating and the small temperature difference between the inside and outside of the parts, the deformation of the parts caused by the vacuum heat treatment process is small.
According to the different cooling medium, vacuum quenching can be divided into vacuum oil cooling, vacuum air cooling, vacuum water cooling and vacuum nitrates isothermal quenching. The main applications of vacuum heat treatment of die casting die are vacuum oil quenching, vacuum air quenching and vacuum tempering. In order to maintain the excellent characteristics of vacuum heating of workpieces (such as dies), it is very important to select and formulate the coolant and cooling process. Oil cooling and air cooling are mainly used in the process of die quenching.
For the die working surface which is no longer machined after heat treatment, vacuum tempering should be used as much as possible after quenching, especially for the workpiece (die) which is vacuum quenched. It can improve the mechanical properties related to the surface quality, such as fatigue performance, surface brightness, and corrosiveness.