Enterprise Name: CHENGDA MODEL SET
Contact person: Business Department
Mobile phone: 198-5734-5006
Address: 39 Success Road, Jiashan Economic Development Zone, Zhejiang Province
Websit : en.chengda-mould.com
The properties of materials themselves need to be achieved by proper heat treatment. Only good heat treatment means can realize our expected performance expectation. According to the material performance requirements of plastic sealing die, heat treatment means of plastic sealing die are mainly high temperature quenching, cryogenic treatment, high temperature tempering, and repeated, through these different treatments, good die performance can be achieved.
1. High Temperature Quenching
In order to improve the rigidity and wear resistance of materials, general materials need to be heated to more than 1030 C. At high temperature, all kinds of alloying elements are fully dissolved in austenite to obtain high matrix hardness during quenching. In order to ensure that the parts do not decarbonize and oxidize, vacuum treatment is adopted accordingly. At present, the high-speed gas quenching furnace used in semiconductor industry can heat the workpiece under high vacuum by nitrogen protection, which not only ensures the decarbonization and oxidation of the workpiece, but also prevents the evaporation of alloy elements. At the same time, the workpiece is quenched and cooled by adjustable gas pressure in the range of 200-500 Kpa, which ensures that the workpiece is fully quenched and reduces the deformation at the same time.
2. Cryogenic treatment and high temperature tempering
After quenching, the martensite transformation point (Ms point) of high alloy steel is higher than that of room temperature. In order to improve the hardness and dimensional stability, cryogenic treatment and high temperature tempering are usually needed to ensure that the retained austenite is fully transformed into stable tempered martensite. After vacuum quenching, the workpiece will be corrected between room temperature and 100 C, and then put into the cryogenic treatment box at - 140 C for cryogenic treatment. The workpiece can be cooled and heated between - 140 and 230 to ensure that the workpiece will not be deformed or cracked because of entering or leaving the furnace. At the same time, the oxidation cracking of the workpiece during tempering is also avoided by using nitrogen protection. At present, for type D2 materials, we usually directly complete three cycles of deep cooling at - 140 to tempering at 230 in cryogenic equipment. For steels tempered above 230 C, such as SAM97, ELmax and ASP23, vacuum tempering furnace is adopted. After vacuum extraction, 99.999% high purity nitrogen is added as medium, convection is formed by changing the direction of blowing air, which ensures the uniformity of temperature of workpiece and saves tempering time.
3. Other Auxiliary Means
While improving the quality of quenching and tempering and cryogenic treatment, die manufacturers have paid full attention to other parts of the workpiece. In the past, the view that the cleanliness of heat-treated workpiece has nothing to do with treatment has been abandoned, and clean pretreatment has been added. Will not be into the furnace parts, through the vacuum cleaning machine for vacuum degreasing, degreasing, drying. It removes all kinds of oil and debris from the workpiece, ensures that the workpiece will not bring other impurities into the furnace, avoids the decomposition of impurities when heated at high temperature, pollutes the furnace environment and the workpiece itself, ensures the cleanliness of the workpiece structure and the perfection of the processing quality from the microscopic point of view, and improves the service life of the workpiece.