Die casting molds are a method of casting liquid metal using a specialized die casting machine. The basic process involves low or high-speed casting of the metal into the cavity of the mold, which has a movable cavity surface that forges the metal as it cools, eliminating defects like shrinkage and loosening and achieving a fractured crystal grain structure. This greatly improves the comprehensive mechanical performance of the casting.
Coating technology, including chemical plating.
Improvement technologies for traditional heat treatment processes.
Surface modification technologies, including surface thermal diffusion treatment, surface phase transformation reinforcement, and electric spark reinforcement.
As there are many materials that can be used as die casting molds, the same surface treatment technologies and processes may produce different effects on different materials. Manufacturers have developed substrate pretreatment technologies based on different mold materials and surface treatment technologies. This optimizes the processing technology for different mold materials, improving the performance of the molds and extending their lifespan. Another direction in heat treatment technology is to combine traditional heat treatment processes with advanced surface treatment technologies to improve the mold's lifespan.
For example, the process of carbonitriding using chemical heat treatment, combined with conventional quenching and tempering processes, is a composite reinforcement called NQN (carbonitriding-quenching-carbonitriding). This process not only achieves a higher surface hardness, but also increases the effective hardening depth, improves the carbonitriding layer hardness gradient distribution, and enhances the stability and corrosion resistance of tempering, which greatly improves the surface quality and performance of die casting molds while maintaining good internal performance.
This type of process includes carbonitriding, nitriding, boronizing, carbonitride-boriding, sulfur-carbonnitriding, etc. Carbonitriding processes can improve the lifespan of both cold, hot, and plastic molds. There are mainly solid powder carbonitriding, gas carbonitriding, vacuum carbonitriding, ion carbonitriding, and carbonitride combined with nitrogen elements in carbonitride atmosphere. Vacuum carbonitriding and ion carbonitriding are technologies that have emerged in recent years. The technology has the characteristics of high speed, uniform carbon concentration, gentle carbon concentration gradient, and small workpiece deformation, making it more and more important in the surface treatment of molds, especially precision molds.