Crystal growth in liquid steel during secondary metallurgy

Morphology of nonmetallic inclusions depends on their crystallographic structure, the growth conditions, and the presence of impurities. Inclusions were extracted from industrial aluminum-killed steel samples and investigated under high-resolution scanning electron microscopy. In this article, the morphology of these aluminum oxide inclusions, including their surface features, is approached from the viewpoint of crystal growth. Commonly, aluminum oxide inclusions are considered to be corundum, but some inclusion shapes prove that other aluminum oxide polymorphs are present as well.