Investigation of the SiC additives effects on mechanical properties of cast irons

Cast irons have a wide range of uses in the industry thanks to their properties. Considering the technological developments from the past to the present, it seems that cast iron has not lost its popularity since its discovery. In particular, the sensitivity of spheroidal graphite cast irons to heat treatment, the mechanical properties of steel and the advantages of production cost have made the use of spheroidal graphite cast irons as engineering materials inevitable. Basically, the use of SiC addivites during production and the effects of this addivites on the mechanical properties of lamellar graphite cast iron (EN-GJL-250) and spheroidal graphite cast iron (EN-GJS-400-15) were investigated. In addition, the processing data was also evaluated. In this study, samples obtained from brake disc and lining castings produced for use in the automotive industry were used. Sand molds were used for casting processes and samples were taken from 4 different castings and tests were carried out. As a result of the tests applied, the chemical composition, microstructure, hardness and tensile strength data of the samples were obtained and a comparative evaluation was made. According to the hardness data, while the average value of 205HB is measured in spheroidal graphite cast iron parts using SiC, this value is 190HB in lamellar graphite cast iron parts. According to the tensile test data, with the use of SiC, σmax values reached 482.7 N/mm2 for spheroidal graphite cast iron and 306.5 N/mm2 for lamellar graphite cast iron. According to the machining results of the parts using SiC in the machining department, 4 more parts were processed in 1 cutting insert for the brake disc and 350 more parts in 1 cutting insert for the lining. As a result of the tests applied, it was observed that with the SiC addivites, the stability in the graphite formation, the increase in hardness values by 8% for lamellar graphite cast iron and 16% for spheroidal graphite cast iron, and the tensile strength increased. It has been noted that the tip consumption decreased in machining. Keywords: Cast Iron, Silicon Carbide, Ductile Iron, Gray Cast Iron