| 摘要 |
<p>PURPOSE:To produce a superclean steel having low oxygen concentration and minimal in residual inclusions by adding a refining agent in which CaO, MgO, etc., and the halides of alkali (earth) metals are incorporated into CaC2 to a molten steel. CONSTITUTION:A refining agent has a composition consisting of, by weight, 10-60% CaC2, <60%, in total, of one or >=2 kinds among CaO, MgO, and Al2O3, and 5-60% of one or more kinds of the halides of alkali (earth) metals. This refining agent is added to a molten steel which is not subjected to deoxidation by means of Al, and these are allowed to react with each other to carry out deoxidation. At this time, deoxidation treatment is performed by shutting off the molten steel from the air because Ca resulting from the decomposition of CaC2 has a strong affinity for oxygen. This method applies to steels of >=0.1% C content.</p> |
