The invention relates to a method for stably controlling the oxidability of ultra-low
carbon steel top
slag. The method comprises the following steps: S1, calculating the addition amounts of
lime andan aluminum-based modifier according to the
slag tapping amount and steel tapping amount of a converter, the TFe content in converter final
slag and the
oxygen content at the end point of the converter; S2, in the RH
oxygen blowing temperature rising process, carrying out
oxygen blowing and aluminum adding at the same time; S3, in the RH oxygen blowing
decarburization process, controlling the oxygen blowing flow of a top lance to be 1,200-2,000 m<3> / h, so that the influence of sharp rising of oxygen in steel on the top slag is prevented; and S4, in the pouring process of a
continuous casting machine, sealing a
tundish, wherein the oxygen
partial pressure in the
tundish is controlled to be 0.3% or below. After the treatment measures are adopted, the content of TFe in the RH refining inlet steel
ladle top slag can be stably reduced to 4% or below, the content of TFe in the RH refining outlet steel
ladle top slag can be stably reduced to 6% or below, then the
castability of
molten steel is remarkably improved, the pouring service life of a single submerged
nozzle can reach that of 6 furnaces or a longer time, and the total
oxygen content of the
tundish is reduced to 0.002% or below.