| 摘要 |
PROBLEM TO BE SOLVED: To prevent the oxidation of residual steel by eliminating the conventional preheating for burning combustion gas in a tundish and to prolong the waitable time until the tundish is reused. SOLUTION: At the time of reusing the tundish 1 in which the steel is remained on the inner wall, N2 being inert gas is heated by being passed from either one of two heat regenerative preheaters 2A, 2B provided at the outer part of the tundish 1 and charged into the tundish 1, N2 is recycled from the other preheater and also, a heat reservoir is heated by combustion burners 5A, 5B. This operation is alternately repeated and the tundish 1 is heated with convective heat transmission of the high temp. N2 passing through the tundish 1 and held to the temp. to be castable. Further, trace amount of H2 of the explosion limit or below is added into the inert gas N2 to make the tundish 1 into the reducing atmosphere and even the residual steel already oxidized is reduced, thus the producing of Al2 O3 is restrained and prevented. Further, the supplying/exhausting gas amount is controlled so as not to become negative pressure in the tundish 1. |
