| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the wearing of an immersion tube and the spalling breakage caused by the rapid temp. change from refining time to waiting time by adjusting the contained components in slag at the time of completing the refining under reduced pressure to specific ratio and coating the adjusted slag on the surface of the immersion tube. SOLUTION: The composition of the slag coated on the surface of the immersion tube 17 is composed of, by wt.%, 55-90% total of Al2 O3 and CaO, 7-25% SiO2 , 1-10% Cr2 O3 and the balance 2-10% one or more kinds among FeO, Fe2 O3 and MgO. In this way, the erosion resistance of the coated layer is improved and the defective slagging and the defective coating on the immersion tube 17 caused by raising or m.p. of the slag, is restrained. Further, the effect of coating protection is improved while preventing the degradating collapse and the spalling caused phase transformation at the time of cooling the coated slag, is improved by regulating the ratio of Al2 O3 /CaO to 0.25-3.0.</p> |
