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Characteristics of chilled cast iron and abrasion-resistant alloy cast iron.

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Chilled cast iron and abrasion-resistant alloy cast iron are commonly used wear-resistant materials in production. Chilled cast iron, also known as chilled iron, is obtained by placing chills in the mold to accelerate the cooling rate of the casting. The

Chilled cast iron and abrasion-resistant alloy cast iron are commonly used wear-resistant materials in production. Chilled cast iron, also known as chilled iron, is obtained by placing chills in the mold to accelerate the cooling rate of the casting. The typical chemical composition of chilled cast iron is: C 3%–3.5%, Si 0.5%–0.7%, Mn 0.5%–0.7%, P < 0.4%, S < 0.07%. Chilled cast iron is characterized by a white iron surface layer, which greatly improves hardness and wear resistance, while the interior remains gray iron to prevent overall brittleness. The chilled surface layer can reach a hardness of about HRC 60, as seen in rolling mill rolls.

Chilled nickel-chromium cast iron is also an example of this type. The Ni content is 4% and Cr content is 1.1%. Ni refines pearlite and graphite, increasing the strength and wear resistance of the cast iron. The addition of Ni also improves hot strength. Chilled nickel-chromium cast iron can reach a hardness of HRC 60 and is often used for manufacturing rolls.

High-chromium cast iron is a high-temperature wear-resistant cast iron, with a typical composition of: Cr 22%–25%, Si 1.2%, Mn 0.3%–0.75%. The addition of Cr improves wear resistance because it forms a dense protective film of Cr2O3 on the casting surface. The addition of Cr also forms carbides, increasing hardness and strength. High-chromium cast iron can be used for wear-resistant parts operating at temperatures above 800°C.

Mud pumps used in drilling are made of abrasion-resistant alloy cast iron Cr15Mo3, which has a hardness of HRC 62 and is one of the most difficult metallic materials to machine.