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: • installation of refractory materials of suitable oxidic composition onto the vessels used for the metallurgical treatment with oxides, which are selected such that the oxides contained in the refractory materials have a basicity which is less than the basicity of the oxides in the steel to be cast so that an acidic reaction of the spinels is minimized. - during the metallurgical treatment: • holding the temperature of the liquid steel 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 the slag composition is adapted such that the basicity of these slags is less than the basicity of the oxides contained in the steel to be cast, • whereby an acidic reaction of the spinels is minimised, • while simultaneously minimising the treatment time between the end of tapping and the start of casting. - in a preparation phase: • installation of refractory materials of suitable oxidic composition onto the vessels used for the metallurgical treatment with oxides, which are selected such that the oxides contained in the refractory materials have a basicity which is less than the basicity of the oxides in the steel to be cast so that an acidic reaction of the spinels is minimized. • installation of refractory materials of suitable oxidic composition onto the vessels used for the metallurgical treatment with oxides, which are selected such that the oxides contained in the refractory materials have a basicity which is less than the basicity of the oxides in the steel to be cast so that an acidic reaction of the spinels is minimized. - during the metallurgical treatment: • holding the temperature of the liquid steel 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 the slag composition is adapted such that the basicity of these slags is less than the basicity of the oxides contained in the steel to be cast, • whereby an acidic reaction of the spinels is minimised, • while simultaneously minimising the treatment time between the end of tapping and the start of casting. • holding the temperature of the liquid steel 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 the slag composition is adapted such that the basicity of these slags is less than the basicity of the oxides contained in the steel to be cast, • whereby an acidic reaction of the spinels is minimised, • while simultaneously minimising the treatment time between the end of tapping and the start of casting.