DISSOLUTION OF HIGH MELTING POINT ADDITIONS IN LIQUID STEEL.

摘要

The kinetics of dissolution of titanium and vanadium in liquid steel has been studied. Two periods were distinguished: the steel shell period and the free dissolution period.; In the case of titanium, it is shown that the customary frozen shell of steel encases the cylinder following its initial immersion. Premature internal dissolution then begins as a result of liquid eutectic of Fe(,0.3) Ti(,0.7) composition forming at the inner steel shell boundary. This phenomenon triggers an exothermic dissolution and erosion of the inner steel shell. The net result is considerable shortened shell melting times. During the free dissolution period, the temperature of the titanium dissolving at the interface increases and the dissolution process becomes self-accelerating.; During the steel shell period with pure vanadium and ferrovanadium alloys, no reaction was observed between the steel shell and vanadium. For low grade ferrovanadium alloys, the dissolution proceeds via a heat transfer mechanism. On the other hand, for high grades, ferrovanadium mass transfer mechanisms dominate.; A simplified mathematical model of the process has been developed to describe the coupled heat and mass transfer phenomena involved in the various systems studied.