Die casting mold is an important part of the mold. With the rapid development of my country's automobile and motorcycle industries, the die-casting industry has ushered in a new period of development. In addition, the requirements for comprehensive mechanical properties and service life of die-casting molds are getting higher and higher. The surface treatment technology requirements for die-casting molds are relatively high. In recent years, a variety of new die-casting mold surface treatment technologies have emerged, but in general, they can be divided into the following three categories: (1) Improvement of traditional heat treatment technology; (2) ) Surface modification technology; (3) Coating technology. Let's take a look at the new technology together!
Die casting mold
1. Improved technology of traditional heat treatment process
(1) On the basis of traditional technology, suitable processing technology is proposed for different mold materials, so as to improve the performance of the mold and increase the life of the mold.
(2) Another development direction for the improvement of heat treatment technology is to combine traditional heat treatment technology with advanced surface treatment technology to increase the service life of die-casting molds.
2. Surface modification technology
(1) Surface thermal diffusion technology
①Carburizing and carbonitriding
carburizing process is used in cold, hot work and surface strengthening of plastic molds, which can improve mold life. When carburizing, the main process methods include solid powder carburizing, gas carburizing, vacuum carburizing, ion carburizing, and carbonitriding formed by adding nitrogen to the carburizing atmosphere.
② Nitriding and related low-temperature thermal expansion technology
This type includes nitriding, ion nitriding, carbonitriding, oxygen nitriding, sulphur nitriding and ternary sulphur carbon nitriding, oxygen, nitrogen and sulphur. These methods have simple processing technology, strong adaptability, low diffusion temperature, small deformation of the workpiece, and are especially suitable for surface strengthening of precision molds, and the nitride layer has high hardness, good wear resistance, and good anti-sticking performance.
③Boronizing
Improved boronizing method. Such as multi-component, paint powder infiltration and so on. A dense and uniform infiltration layer can be obtained, the hardness, wear resistance and bending strength of the surface infiltration layer of the mold are improved, and the service life of the mold is increased by more than 2 times on average.
④ Rare earth surface strengthening
In the mold surface strengthening, rare earth elements are added, which greatly affects the improvement of the mold surface structure, surface physical, chemical and mechanical properties. It can significantly increase the thickness of the infiltration layer of various infiltration methods, increase the surface hardness, and at the same time make the structure of the infiltration layer fine and diffuse, and the hardness gradient is reduced, so that the wear resistance, cold resistance, and thermal fatigue properties of the mold are significantly improved, thereby greatly improving Mold life.
(2) Laser surface treatment
Using laser cladding VC layer on H13 substrate, the obtained mold surface is essentially continuous, dense and non-porous VC steel composite coating. It not only has strong oxidation resistance at 600℃, but also has strong The ability to resist the reduction of molten metal.
(3) EDM deposition cermet process
makes good use of the high wear resistance, high temperature resistance and corrosion resistance of cermet materials, and the process is simple and the cost is low. It is a new way of surface treatment for die-casting molds.
3. Coating technology
(1) Coating technology, as a kind of mold strengthening technology, is mainly used in plastic molds, glass molds, rubber molds, stamping molds and other mold surface treatments with relatively simple working environments.
(2) The surface of the die-casting mold is strengthened by chemical composite plating to improve the adhesion resistance and demoldability of the mold surface. In this method, (NiP)-polytetrafluoroethylene composite plating is performed after the polytetrafluoroethylene particles are infiltrated on the aluminum-based die-casting mold. Experiments have proved that this method is feasible in process and performance, and greatly reduces the friction coefficient of the mold surface.
Mold pressure processing is an important part of mechanical manufacturing, and the level, quality and life of the mold are closely related to the mold surface strengthening technology. With the advancement of science and technology, various mold surface treatment technologies have made great progress in recent years. In view of the fact that surface treatment is one of the important means to improve the life of die-casting molds, to improve the overall level of die-casting mold production in my country, surface treatment technology will play a pivotal role.
