Wear-resistant cast iron Wear-resistant cast iron

- Jul 16, 2019-

In 1981, China's ductile iron experts used modern scientific methods to study the 513 pieces of ancient Han and Wei irons unearthed. Through a large amount of data, it was determined that spheroidal graphite cast iron appeared in China in the Han Dynasty. The relevant papers were read at the 18th World Congress of Science and Technology History, which sensationalized the international foundry industry and the history of science and technology. Experts in the history of international metallurgy verified this in 1987: ancient China has already explored the law of making ductile iron with cast iron softening, which is of great significance for the re-segmentation of the world metallurgical history. The process is: various castings are heated to a temperature of 860-900 ° C, the original substrate is all austenitized and then cooled in oil or molten salt to achieve quenching, and then heated and tempered at 250-350 ° C, the original matrix conversion For tempered martensite and retained austenite structure, the original spheroidal graphite has the same shape. The treated casting has high hardness and certain toughness, retains the lubricating properties of the graphite, and improves the wear resistance. Ductile iron parts are used as shaft parts, such as crankshafts and connecting rods of diesel engines, which require high-strength mechanical properties with high toughness and good toughness. The process is as follows: the cast iron piece is heated to a temperature of 860-900 ° C to keep the matrix austenitized, and then quenched by cooling in oil or molten salt, and then tempered at a high temperature of 500-600 ° C to obtain tempered sorbite structure. (Generally there is still a small amount of lumpy ferrite), and the original spheroidal graphite has the same shape. After treatment, the strength and toughness are well matched, and it is suitable for the working conditions of the shaft parts. The metallurgical industry is usually divided into the black metallurgical industry and the non-ferrous metallurgical industry. Many varieties in the charge belong to ferrous metallurgy, mainly including iron, pig iron, steel and iron alloy. Iron-carbon alloys containing a small amount of alloying elements and impurities in steel, can be divided according to the carbon content: steel is re-refined by pig iron, has high mechanical strength and toughness, and also has heat resistance, corrosion resistance and resistance. Special properties such as grinding