A mathematical model for determining the variations of a temperature of molten steel, t_m and a concentration of carbon in steel bath, C_m caused by the melting of scamp fed into LD converter is developed in this work.
Experimental data obtained by others in the blowing process of LD converter were plotted on the figure of C_m vs. t_m. It was noted from this figure that there were considerable differences between the data for the case where scrap had not been fed into converter and those with feed of scrap, and that the data obtained where all of scrap had not yet been molten indicated the variation of C_m with t_m along a liquidus line of the iron-carbon phase diagram in accordance with the progress of the blowing time.
Behaviors of C_m and t_m accompanied by the fluctuations of these process variables caused by the changes of operating conditions were analysed in terms of the model mentioned above. And, on the basis of these behaviors, a method of a end-point dynamic control with the aid of a topological phase diagram was proposed in this paper.