Abstract：In order to improve surface quality of hypoperitectic steel slab cast at high speed, several factors, such as overheat temperature, ratio of manganese and sulphur, temperature of mold copper plate, average heat flux and powder properties are discussed. It is easy to cause longitudinal cracks in and depressions on slab cast with high overheat and strong secondary cooling. With the increase of casting speed, there is a tendency to make depressions. Depressions are appeared on inner side than on outer side of the slab. The longitudinal cracking is promoted by uneven heat flux, the average heat flux and temperature of copper pates are important factors for cracking. Compared with using powder of lower basicity, using powder of higher basicity can reduce heat flux and temperature of copper plate, realize soft cooling, make solidified shell uniform and improve surface quality of slab.
2006, Vol. 41 