The aluminum alloy die-casting process is widely used in the automotive, electronics, aviation, and other industries due to its high efficiency and high precision. However, during the die-casting process, mold corrosion may cause many problems in the production process. As a comprehensive aluminum alloy die-casting enterprise integrating product design, mold design and development, product production, surface treatment, packaging, transportation, and sales, Mindwell combines With more than 20 years of experience in the aluminum alloy die-casting industry, I will discuss with you the issue of mold corrosion during the aluminum alloy die-casting process.
Types of mold corrosion
Mold corrosion is a very common and unavoidable problem. The causes of corrosion are also complex, but they are always changing. Generally speaking, they can be divided into three types: cavitation, erosion, and chemical corrosion.
Mold cavitation
Mold cavitation refers to the formation of gas holes in the mold or on the surface of the casting during the die-casting process. These gas holes are generally round or oval in shape and unevenly distributed, forming obvious depressions or bulges in the casting. Mold cavitation is mainly caused by the failure of hydrogen or other gases released by the metal during the solidification process to be discharged smoothly. The main reasons include the presence of gas in the molten metal, poor exhaust of the mold, etc.
Erosion
Erosion refers to the process of impact wear of molten metal fluid on the surface material of the mold during the die-casting process. Erosion usually manifests itself as local wear, pits, scratches, etc. on the mold surface. Erosion is mainly caused by the high temperature, high-speed flow, and impact force of molten metal that causes mechanical damage to the mold surface. The severity of erosion is related to factors such as the flow rate, temperature, gas content of the liquid metal, and the material hardness of the mold.
Chemical corrosion
Chemical corrosion refers to the chemical reaction between the molten metal and the mold surface material during the die-casting process, resulting in corrosion damage to the mold surface. Chemical corrosion usually presents problems such as discoloration of the mold surface, corrosion pits, and a decrease in surface quality. Chemical corrosion is mainly caused by the interaction between molten metal and mold materials, such as the corrosion of aluminum alloy on steel molds.
In short, mold cavitation is the holes formed by gas during the die casting process. Erosion is the impact wear of the metal fluid on the mold surface. Chemical corrosion is the corrosion damage caused by the chemical reaction between the metal and the mold material. . These corrosion phenomena will have adverse effects on the service life of the mold and product quality, so corresponding preventive measures need to be taken in the die-casting process to mitigate their effects. In addition, the aluminum alloy molten itself, high temperature, and high pressure will also cause certain corrosion to the die-casting mold.
What influence will mold corrosion have on the production of aluminum alloy die castings?
- Leading to poor quality of die castings: Mold corrosion will cause the surface roughness of die castings to become larger, bubbles, pores, and other defects to appear, reducing the quality of aluminum alloy die castings.
- Shortened mold life: After the mold is corroded, its surface finish decreases and friction increases, which accelerates mold wear and fatigue damage, resulting in shortened mold life, increased production costs, and reduced market competitiveness of the company.
How to reduce corrosion of aluminum alloy die-casting molds?
- Choose the right mold material: Choose mold materials with good corrosion resistance, such as stainless steel molds with specially treated surfaces, which can effectively resist corrosion during the aluminum alloy die-casting process.
- Control process parameters: Reasonably control process parameters such as aluminum alloy pouring temperature and pressure to avoid excessive temperature and pressure that make the mold surface vulnerable to corrosion.
- Prevent the entry of gases and impurities: Take effective measures, such as using appropriate filtering devices, to prevent gases and impurities from entering the molten aluminum and reduce the occurrence of corrosion.
- Surface protection treatment: Perform special coating or coating treatment on the surface of the mold to improve the corrosion resistance of the mold.
- Regular maintenance and upkeep: Clean, maintain, and repair the mold regularly, promptly deal with corrosion problems on the mold surface, and extend the service life of the mold.
Through the above measures, the occurrence of mold corrosion during the aluminum alloy die-casting process can be effectively reduced, the quality of the die-casting parts and the service life of the mold can be improved, thus creating greater economic benefits for the enterprise.