Mold filling of heavy ingot can be performed in two ways: top pouring and
Top pouring, the molten steel is more exposed to air, suffering from
reoxidation problems. As the pouring steel impinges on the melt surface
inside the mold, it carries reoxidation products and mold powder, floating
on it, back into the bulk, resulting in macro-inclusions. Moreover, during
filling, metal splash adheres to the mold walls and produces surface defects
on the ingot skin, which subsequently needs surface conditioning. This makes
the top pouring method not suitable for high-quality steels.