The cooling rate of metal mold of casting is tens to hundreds times that of sand mold, which directly affects the formation of unique structure of cast iron. There are many factors that control the microstructure of as cast metal mold cast iron under high cooling rate. In addition to obtaining the expected as cast metallographic structure, comprehensively solving the following factors can greatly improve the productivity and metal mold life, thus reducing the cost, increasing the benefit and expanding the application range of metal mold cast iron, which is the key to the development of metal mold cast iron technology. The thermal interaction between molten iron and metal mold is an important factor to determine the quality and mold life of FPM castings. The metal mold shall have high thermal conductivity, heat resistance and thermal shock, oxidation resistance, wear resistance, easy combination with coating, good forming and processability and can be repaired. The metal type material is generally uniform A-type graphite gray cast iron. In some cases, cr0.5% ～ 1.0%, Mo (0.6 ± 0.1)%; Hypereutectic or low sulfur gray cast iron can resist thermal shock and improve the service life of metal mold. Gray cast iron metal mold is used for medium and small parts, with a general mold life of 2000 ~ 5000 times. In the casting cost, the metal mold cost generally accounts for 10%. In addition, the water cooling system for external welding of thin steel metal profile can be used, which can have a long service life. Cu Zr alloy is a promising metal mold.
