Cast iron possesses many superior characteristics caused from precipitated graphite structure, for example, castability; wear resistance, solid lubrication, damping capacity. But the more graphite hyper-eutectic cast iron contains, the lower its mechanical strength becomes, because graphite gives a negative effect to strength of cast iron. In addition, primary graphite tends to segregate during solidification, so uniform materials are difficult to be produced. In this study, authors introduced semi-solid processing in developing new and high quality cast iron. A series of semi-solid processing experiments were carried out to clarity the effect of stirring condition, solidification temperature and etc. on microstructures and characteristics of cast iron. In particular much attention is paid to the appearance of ternary eutectic zone at the final stage of solidification. As the results advanced hyper-eutectic cast iron was obtained with high quality of both the mechanical strength and wear resistance. As for the mechanical strength, 300MPa and 0.60 percent are obtained as the tensile strength and the elongation values, respectively, under the controlled stirring condition. This indicates that semi-solid processed hyper-eutectic cast iron is used prospectively without spheroidization.
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