| 摘要 |
<p>PURPOSE:To easily produce an extremely low carbon and extremely low sulfur steel at a low cost by plasma-heating molten steel from the upper part after completing vacuum decarburizing treatment, stirring, spreading reducing agent on slag to make the slag the specific basicity and desulfurizing. CONSTITUTION:The molten steel 5 completing the vacuum decarburizing treatment is charged into a ladle 1 and guided to a plasma heating treatment device and an upper cover 3 is fitted and Ar as is introduced into an upper space from an introducing hole 7. Successively, plasma torches 4 are inserted from torch inserting holes 8 to generate the plasma 9 and the Ar gas is introduced from a blowing device 2 at the bottom part of a ladle 1 to stir the molten steel 5 and the slag 6. Further, the slag reducing agent is charged from a charging hole 11, and while adjusting the slag basicity so as to become <=7, the desulfurizing treatment is executed. By this method, the desuldurization of the molten steel 5 can efficiently be executed.</p> |
