Modification of Al 2 O 3 inclusions in medium carbon aluminium killed steels by AlCaFe additions

Abstract

Plant trials were carried out to assess the effect of the addition of AlCaFe as an agent for modifying Al₂O₃ inclusions in medium carbon aluminium killed steels. The size distribution of inclusions in ladle furnace and tundish samples showed that most were smaller than 10 μm. Furthermore, the number of inclusions and the inclusion area fraction at the tundish were significantly smaller compared with those found at the ladle furnace after AlCaFe additions. The modification degree of Al₂O₃ inclusions was widely heterogeneous after AlCaFe additions. However, the inclusion population was homogeneous for the tundish samples, with CaO/Al₂O₃ weight ratios corresponding to adequate inclusion modification. These results are similar to those obtained in typical heats in which CaSi was used as an inclusion modifying agent.