METHOD FOR THE METALLURGICAL TREATMENT OF KILLED STEELS TO BE CAST CONTINUOUSLY, TO REDUCE SURFACE DEFECTS IN THE END PRODUCT

摘要

Method for the metallurgical treatment of aluminium-killed steels to be cast continuously to reduce surface defects in the end product, comprising the following steps: in a preparation phase: selection and installation of refractory materials of suitable oxidic composition onto the vessels used for the metallurgical treatment, for example ladle, tundish, ladle shroud and submerged entry nozzle with oxides, so that an acidic reaction of the spinels is minimised: during the metallurgical treatment: selection of the tapping temperature in a way that the liquid steel remains as long as possible within a temperature range above 1600 °C during the metallurgical treatment, addition of a limited amount of aluminium at a temperature above 1600 °C, while a feed of oxygen is prevented to minimise the new formation of spinels, slag conditioning in a way that: an acidic reaction of the spinels is minimised, the concentration of the oxides of the slags at the steel/slag interface as spinel proportions is less than that of the oxides contained in the steel, while simultaneously minimising the treatment time between the end of tapping and the start of casting.