EFFECT OF SILICON CONTENT ON THE HOMOGENEITY OF HARDNESS AND WEAR RATE PROPERTIES OF GREY CAST IRON USED FOR CANDIDATE OF BRAKE SHOE OF TRAIN

Suryo Darmo, Lilik Dwi Setyana, Tarmono, Nugroho Santoso

Abstract: Generally there is the the segregation of chemical composition in the brake shoe made of grey cast iron which it used for train. Silicon content of the outside and the inside of grey cast iron is differed, since it is mainly influenced by the different cooling rates between the outside and the inside parts of the castings. This condition results in the different hardness and wear rates of the brakes, caused by decreasing of the thickness of the brake after its operation time by time. The hardness and wear rate are directly affected by the amount of graphites and mechanical properties of the phases in gray cast iron. The purpose of this study was to obtain the data of the hardness and wear rate of the grey cast iron, for five variation of silicon content. The liquid of gray cast iron used in this study has composition of 3.34% C, 2.46% Si, 0.313% Mn, 0.0553% P, 0.106% S, 0.302% Cr, 0.0770% Mo, 0.0527% Ni, 0.0070% Al, 0.168% Cu, 0.020% Sn, 0.0207% Ti, 0.0100% V, and 0.0017% Mg. Ferro silicon (75% Si) is used to increase the silicon content in the liquid of gray cast iron, to obtain the five kinds of silicon content of gray cast irons. The results of the study showed that the best homogeneity of the hardness and wear rate are obtained in gray cast iron of containing of 3.51% C, 3.35% Si, 0.294% Mn, 0.148% P, 0.134% Cr, 0.0448% S, 0.0070% Al, 0.157% Cu, 0.022% Sn, 0.020% Ti, 0.0100% V, 0.0019% Mg.

Keywords: Segregation, Homogenity, Hardness, and Wear rate

DOI: https://doi.org/10.15623/ijret.2018.0704001