| 摘要 |
PURPOSE:To produce high carbon special steel of different contents of C efficiently from the same molten steel by using the low P molten iron which is beforehand reduced of conent of P to the prescribed content or below, subjecting the same to refining consisting essentially of decarbonization in an oxygen refining furnace, and tapping a constant amt. of the molten steel at every prescribed content of C. CONSTITUTION:Molten iron is beforehand subjected to pretreatments to prepare low P molten iron of <=0.050%, more preferably <=0.020% P. Then, this low P molten steel is subjected to the refining virtually similar to ordinary refining from the start of the refining till the first tapping. In the refining succeeding to this, the rate of feeding oxygen is lowered in consideration for the decrease in the amt. of the molten steel by the first tapping whereby the steel ingot is produced. In the process of this invention, the prescribed amt. of the molten steel is tapped at every prescribed content of C, and the molten steel temp. in all the tapping is maintained at >=1,600 deg.C for the purpose of continuous casting or ordinary ingot making in the next stage. By this method, the effective production of high carbon special steel in large sized oxygen refining furnaces which was heretofore difficult is made possible, and the steel kinds of small demand are produced in the same manner as for general carbon steel. |
