Dynamic Evolution of Inclusions in Ti‐Bearing Al‐Deoxidized Molten Irons at 1873 K

Abstract

Abstract To study the evolution of inclusions in Ti‐bearing Al‐deoxidized steel, four types of molten irons with different Al and Ti contents were prepared. Subsequently, scanning electron microscope (SEM) and high‐temperature confocal scanning laser microscope (CSLM) were used to investigate the dynamic process of inclusions in the samples. The CSLM showed that Al 2 O 3 inclusions strongly attracted each other and agglomerated easily. In high‐Al and high‐Ti melt, although inclusion clusters were frequently observed, its number and size were small. The Al–Ti–O cluster appeared much denser, unlike the Al 2 O 3 cluster, which had loose structure. In high‐Al and low‐Ti melt, the number of inclusions was large, whereas their size was small. Collision among small inclusions was not observed, possibly because the trace of Ti addition accelerated the dispersion of inclusions. In low‐Al and high‐Ti melt, typical inclusions of Al–Ti–N–O were observed, and they always had irregular or bar‐like shapes or form a cluster. The bar‐like inclusion was found to adhere easily to a cluster via bridging or packing. In low‐Al and low‐Ti melt, only small amount of inclusions were observed. The inclusions presented nearly spherical in shape, and few cluster could be seen. In addition, the phenomenon of collision and agglomeration among the inclusions was never observed.