Inclusions in a Runner after Casting of Bearing Steel

In uphill teaming method of ingot casting molten metal from ladle goes into the runner system which feeds one or several ingot molds. This method is still one of important methods for production of bearing steel and some low-alloy steel grades. In order to make clean steel which has few and controlled amount of inclusions, good understanding of inclusions characteristics seems to be necessary. In this work inclusions of steel left in the runner part of ingot casting system were investigated. Inclusion type, size, and morphology were the main characteristics of this study. Both light optical and scanning electron microscopes were used to assess inclusion size and morphology. Chemical composition of inclusions were determined by SEM equipped with EDS and both qualitative (element mapping) and quantitative micro area analyses were preformed. Three main detected types of inclusions were oxides, sulfides and complex. The most frequent inclusions in the runners were MnS, SiO2 and Al2O3 inclusions.