OPTIMIZATION OF SECONDARY COOLING DURING CONTINUOUS CASTING OF STEEL SLABS

The article describes an approach to decreasing the rejection rate of the steel plates due to the surface defects in the rolling mill achieved by optimization of air-water secondary cooling on the continuous casting machine (CCM) of steel. In context with the occurrence of the surface cracks on the steel plates a complex analysis of possible reasons causing the creation of monitored cracks was made. Control of all technological procedures, including setting parameters of the CCM, was introduced. On the basis of statistic evaluation of selected technological parameters and according to the occurrence of specific cracks on the steel plates, of which their character signalize the possibility to create the cracks due to effect of the secondary cooling, the calibration, nozzles replacement and adjustment of the casting parameters in this cooling area was performed. Optimization of secondary cooling adjustment was made for the steel grade S355.