| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an extremely low-carbon steel by which the optimum RH final circulation time can be decided. <P>SOLUTION: In the method for manufacturing the extremely low-carbon steel by using the RH, the total oxygen concentration and the Al concentration in the molten steel are analyzed during the circulation of the molten steel, and the circulation ling time is adjusted so as to finish the molten steel circulation within the range of the following (1) and (2) inequalties based on these values. In the case of being 0.065≥[%Al]>0.030 mass%; 0.043×T.[O]+1.0≤t≤0.043×T.[O]+2.0 (1), and in the case of being 0.005<[%Al]<0.030 mass%; 0.043×T.[O]+100×(0.03-[%Al])+1.0≤t≤0.043×T.[O]+100×(0.03-[%Al])+2.0 (2). Wherein, [%Al]: the Al concentration (mass%) in the molten steel, T.[O]: the total oxygen concentration (ppm) in the molten steel and t: the time (min) till stopping molten steel circle-flowing after taking a sample for analyzing T.[O]. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
