| 摘要 |
The present invention relates to a new, high-speed decarburization method simultaneously using lower side blowing and top side blowing to additionally inject a mixed gas of gaseous oxygen and argon or nitrogen by actively using a lance for top blowing rather than relying only on lower side blowing injection unlike existing blowing operations for decarburizing austenitic stainless steels to 0.03-0.1% in a refining furnace. The present invention provides a high-speed decarburization method for austenitic stainless steels with a target carbon concentration of 0.03-0.1% using an AOD refining furnace by: injecting a lower-side blown mixed gas containing oxygen into a molten steel using a tuyere in the lower part of the AOD refining furnace; and additionally injecting a top-blown mixed gas containing oxygen with the lower-side blown mixed gas simultaneously until the end of a decarburization process, while the oxygen is injected to the upper part of the refining furnace through a top-blown lance at the same time during the early stage of decarburization. According to the present invention, decarburization operation time for molten steels in a refining furnace can be shortened by increasing decarburization speeds of molten steels compared to the past through increasing a total amount of oxygen injected in a molten steel for a unit time by introducing a combined blowing method of side blowing and top blowing in active utilization of the top-blown lance in the upper part of AOD. [Reference numerals] (AA) Step 2-4 time; (BB) Comparative example; (CC) Embodiment example |
