Abstract
Using a high-frequency induction furnace in which atmosphere could be controlled, effect of temperature, area in contact with crucible wall, area of free surface and rotation on the rate of decarbonization was studied. The following results were obtained.
(1) The rate of decarbonization (this rate is difference between the total rate of decarbonization which is measured and the rate of decarbonization by crucible wall (MgO), and the following rates are the same.) increases linear to temperature (1550-1650°C), and the activation energy calculated from this results is 34·6 kcal/mol.. This value is greater than the values of other investigators, because calculating the activation energy, they do not subtract the rate of decarbonization by reaction of crucible wall (MgO) from total rate of decarbonization.
(2) The rate of decarbonization is constant on condition that the area of free surface of molten steel is constant, and have no connection with the area in contact with crucible wall. By calculating from this results, it becomes clear that in this experiments, the reaction of decarbonization occurs mainly at free surface, and the reaction in molten steel and through boundary layer between molten steel and gas phase of crevices in the crucible wall is extremely small.
(3) The rate of decarbonization increases linear to the area of free surface. This fact indicates that the reaction of decarbonization occurs mainly at free surface.
(4) The rate of decarbonization in case of rotation increases linearly to the area of free surface of paraboloid of revolution. But this inclination of the straight line is smaller than the inclination by increase of free surface in case of rest, because the condition of stir by high-frequency induction power is changed by rotation.
