Abstract
The relation between iron oxide in molten slag and oxygen in molten metal in 160 t LD converter are studied, and the main results obtained are as follows.
(1) During the period between end point and tapping the oxygen content in molten metal changes in a range of ±150ppm in low carbon steel (0.04%-0.08%C).
(2) This change of oxygen in molten metal depends on the total FeO content of molten slag. When the total FeO content in slag is high, oxygen content in metal increases between end point and tapping. On the other hand, when the total FeO content is low, the oxygen content decreases.
(3) At the end of oxygen blowing the slag temperature is higher than that of metal. The difference in temperatures seems to be over 50°C. This difference, however, vanishes during the period between the end point and tapping. This decrease of slag temperature after the end of blowing reduces the oxidizing potential.
(4) As a consequence, the oxidizing potential of slag becomes lower than that of metal at tapping. In the smelting of low carbon steels, this phenomenon is observed in approximately one third of the heats, but scarcely in medium and high carbon steels.
