RESEARCH AND DESIGN OF THE COMBINED CCM MOLD LEVEL CONTROL SYSTEM

Abstract

the ingot internal uniformity, which is mainly determined by the initial solidification processes.
The imperfection of the casting process control at the initial section "ladle-tundish-mold", especially
the mold level, leads to occurrence of internal nonuniformity and surface defects, as well
as distortion of the slab shape. Thus, the level drop below setting value leads to inner surface oxidation
of the formed ingot crust and its structural nonuniformity. If metal level increases, overflow
over the ingot crust occurs, which leads to increase the oscillation traces depth and capture of
non-metallic and slag inclusions. Therefore, the mold is the most important technological element
of the continuous casting machine (CCM). The scientific and technical complexity of the mold
level control problem is the lack of technical capability of the metal level measuring in real technological
conditions with the required accuracy, as well as changes in the object parameters during
operation and in non-stationary modes. The modernization of existing control systems through
the introduction of new control algorithms is one of the ways to improve the efficiency of the metal
level stabilization control in the continuous casting machine mold. It demands to single out the
factors affecting the metal level stability in order to observe and compensate them. In this paper
implementation of the combined control principle based on the main disturbances compensation
and controlled coordinate feedback is proposed. The synthesis of static compensators with constant and variable compensation coefficients was carried out in accordance with the principle of
invariance, which allows to significantly reduce the deviation of the controlled variable in nonstationary
operating modes.