Characteristics of chilled cast iron and wear-resistant alloy cast iron

Chilled cast iron and wear-resistant alloy cast iron are commonly used wear-resistant materials in production. Chilled cast iron, also known as chilled cast iron, is obtained by placing chilled iron in the mold to speed up the cooling rate of the casting. The typical chemical composition of chilled cast iron is: C content of 3% ~ 3.5%, Si content of 0.5% ~ 0.7%, Mn content of 0.5% ~ 0.7%, P content of less than 0.4%, s content of less than 0.07%. Chilled cast iron is characterized by white cast iron on the surface, greatly improving hardness and wear resistance, and maintaining gray cast iron structure inside to prevent overall embrittlement. The hardness of quenched surface layer is about HRC60, and calender roll is an example.
Quenched nickel chromium cast iron is also an example. The Ni content of quenched Ni Cr cast iron is 4% and Cr content is 1.1%. Ni refines pearlite and graphite and increases the strength and wear resistance of cast iron. The addition of Ni can also improve the thermal strength. The hardness of quenched Ni Cr cast iron can reach HRC60, which is often used to make rolls.
High chromium cast iron is a high-temperature wear-resistant cast iron. Its typical composition is: Cr content 22% ~ 25%, Si content 1.2%, Mn content 0.3% ~ 0.75%. The addition of Cr can improve the wear resistance of cast iron, because CR can form a dense protective film Cr2O3 on the surface of the casting. The addition of CR also generates carbides, which improves the hardness and strength of cast iron. High chromium cast iron can be used to make wear-resistant parts working at high temperature above 800 ℃.
The mud pump used in drilling is made of wear-resistant alloy cast iron crl5mo3, with a hardness of HRC62. It is one of the most difficult metal materials to cut at present.