What is ductile iron?

Ductile iron is a high-strength cast iron material developed in the 1950s, with comprehensive properties close to steel. Based on its excellent properties, it has been successfully used to cast some parts with complex forces, high strength, high toughness, and high wear resistance. Ductile iron has rapidly developed into a widely used cast iron material second only to gray cast iron.

　　Ductile iron is a high-strength cast iron material developed in the 1950s, and its comprehensive performance is close to that of steel. It is based on its excellent performance that it has successfully cast some parts with complex force, high strength, high toughness, and high wear resistance. Ductile iron has rapidly become a widely used cast iron material. The so-called "replacing steel with iron" mainly refers to ductile iron.

　　Ductile iron can obtain spherical graphite through spheroidization and inoculation treatment, which effectively improves the mechanical properties of cast iron, especially the plasticity and toughness, and obtains higher strength than carbon.

　　What is the development history of ductile iron?

　　Réaumur of France manufactured centesimal iron. Later, Seth Boyden of the United States invented ductile iron in 1826.

　　Knowing the twentieth century. Due to the progress in the main components of cast iron such as C, silicon, etc. and other influences, melting methods, inoculation effects, etc., the so-called cast iron appeared. Therefore, the material has been greatly improved, and the application range has been increased to a certain extent. However, due to this fundamental shortcoming, the scope of application could not be expanded rapidly. Later, Moro of Smoke appeared cast iron with spherical graphite in the as-cast state.

　　Ce was added to high-carbon, low-sulfur gray cast iron, and the remaining amount was kept above 0.02% to produce ductile iron. Almost at the same time, American International Nickel (INCO) GAGNEVIN et al. added MM to cast iron.

　　During World War II, there were insufficient resources to produce wear-resistant martensite, and the replacement of Cr became a top priority. Therefore, a systematic investigation was conducted on whether various metals that chemically combine with C and the transition form C compounds, including magnesium. When adding, Cu80 1 Mg20 alloy and Ni80-M920 were used to slow down the violent bounce. The results show that as a substitute element for chromium, it not only has a good effect, but also has a significant desulfurization effect when there is residue in the molten iron. Based on these new findings, the effect of adding magnesium to gray cast iron after white cast iron was also studied. Adding 0.5% Mg to gray cast iron including C 3.5%, Si2.25%, Ni 2%, its tensile strength far exceeded the original prediction (generally gray cast iron is about 13kgf/mm2), which is 78kgf/mm2.

　　What are the constituent components of ductile iron?

　　Cast iron is an iron-carbon with a carbon content exceeding 2.11%. Industrial pig iron, scrap steel, etc. and its materials can be obtained by high-temperature melting. In addition to Fe, C of other cast iron is precipitated into graphite. If the precipitated graphite is engraved, the cast iron is called gray cast iron or gray cast iron, the worm cast iron is called soft ink bead iron, and when it flows into lumps, the cast iron is called malleable ductile iron. The chemical composition other than that is generally C content 3% ~ 4%, silicon content 1.8% ~ 3.2%, manganese, phosphorus, sulfur total amount below 3%, and appropriate amount of rare earth and other spheroidizing elements.