| 摘要 |
<p>PURPOSE:To produce a clean steel minimal in the content of Al2O3 as nonmetallic inclusion by tapping molten steel from a converter into a ladle, removing the greater part of the concurrently flowing molten slag, diluting FeO and MnO in the remaining molten slag, and successively performing degassing refining in a vacuum degassing apparatus and simultaneously carrying out deoxidation by means of Al. CONSTITUTION:After molten steel and molten slag are moved from a converter into a ladle, highly oxidizing molten slag is removed. A slagging agent in which 50+ or -5% CaO and 50+ or -5% SiO2 are mixed so that the ratio between them is regulated to 1:1 is added onto the molten slag remaining on the molten steel in the ladle to form a molten slag having a basicity of one and free from FeO and MnO, by which the concentrations of FeO and MnO in the remaining molten converter slag are diluted and the amount of O2 contained in the molten steel is reduced. The above molten steel is poured into an RH-type vacuum degassing apparatus and the amount of O2 in the molten steel is reduced by means of vacuum degassing treatment, and simultaneously, Al as a deoxidizer is added to allow O2 remaining in the molten steel to react with Al so as to be absorbed by the molten slag in the form of Al2O3, by which the clean steel minimal in nonmetallic inclusions, such as Al2O3, can be easily produced.</p> |
