Influence of SiC and FeSi as silicon carriers on the characteristics of gray cast iron

The Influence of silicon carbide and ferrosilicon as silicon sources on the cooling curve, microstructure and chill depth of hypoeutectic gray cast irons in different holding times, pouring temperatures and carbon equivalents has been studied. It is concluded that addition of SiC to the melt resulted in increased temperature of austenite formation and eutectic transformation. Results of microstructural studies revealed that SiC addition resulted in a more uniform distribution of type A graphite and refined eutectic cells and has little effect on graphite size. These observations were attributed to the pre-inoculation behavior of SiC in gray cast iron. Also for SiC treated cast irons with carbon equivalents higher than 3.7%, decreased hardness and chill depth were observed. The graphitization potential of SiC treated cast irons showed higher carbon equivalents as compared with FeSi treated cast iron melts.