Abstract
Theoretical and experimental studies were carried out to quantitatively understand the effect of reaction sites on the decarburization rate of ultra low carbon steel.
The decarburization rate was studied in a 30kg vacuum induction furnace by varying the areas of three reaction sites such as bath surface, steel melt-crucible interface and inner part of molten steel.
With the oxygen content of 400ppm, the ratio of the decarburization rate at the bath surface to the overall one is largest for [C] ≤27ppm, whereas the largest is that of the inner part of molten steel for [C] ≥27ppm.
The fluiddynamic calculation of the flow pattern of CO bubbles nucleated inside the molten steel of RH vacuum vessel made clear that a part of CO bubbles near the down-leg was sucked into the ladle and dissolved into the steel melt without decarburization. The effect of each reaction site on decarburization rate in RH was calculated to be the same tendency as that in the 30kg induction furnace.
