Control method of mold level for fast continuous casting process

摘要

PURPOSE: A method is provided which controls a surface level of molten metal so that the surface level of molten metal is stably and reliably maintained in the high speed continuous casting process with a casting speed of 4 mpm or more despite of various disturbances. CONSTITUTION: In a method for controlling a surface level of molten metal inside a mold in the continuous casting process, the method for controlling the surface level of molten metal comprises the steps of filtering signals inputted from the outside, and judging if a frequency abstracted by performing FFT(fast fourier transform) algorithm on signals of the surface level of the molten metal among the filtered signals satisfies the set frequency range; obtaining a first output control term £KD(dh/dt)| by differentiating the error £KP(hr-h)| after obtaining an actually measured surface level of the molten metal(h) by operating a notch filter in case that the abstracted frequency is included in the set frequency range, and obtaining an error £KP(hr-h)| from a standard surface level of the molten metal(hr); calculating a second output control term(SnKN) by obtaining a standard position of stopper from a mold size(Am), a measured casting speed(v) and a tundish weight(Tw); calculating a third output control term(Kf Sfdt) by integrating a fuzzy output(St) calculated using a fuzzy rule set from the error of surface level of the molten metal(hr-h) per time; and obtaining a final position of a stopper(Sr) by summing up the calculated first, second and third output control terms, and controlling the stopper according to the final position of the stopper.