| 摘要 |
<p>PURPOSE:To accelerate the reaction of Si deoxidation and reduce the amount of large-size inclusions such as of calcia base and alumina base by adding a silicon deoxidizer into the molten steel in a ladle then controlling the slag to basicity and stirring the molten steel by blowing Ar gas therein thereby accelerating Si deoxidation reaction. CONSTITUTION:A silicon deoxidizer (e.g., ferrosilicon of low Al low Ti) is added into the molten steel 3 in a ladle 1, after which the basicity of the slag is controlled to preferably about 2 or more. Next, a cover 2 is placed on the ladle 1 and the spacing at the top surface of the molten steel 3 is made Ar gas atmosphere. At the same time, Ar gas or the premelt flux containing CaO; 50-90%, Al2O3; 10-30% and CaF2; 5-40% together with the Ar gas is blown through the lance 4 immersed in the molten steel, whereby the molten steel 3 is stirred. According to this method, the low oxygen steel of 0 amount about 40ppm (total 0 amount) or less is obtained and since oxidizers such as Ca, Al are not used, the amount of non-ductile and nearly spherical inclusions may be considerably reduced.</p> |
