| 摘要 |
PURPOSE:To obtain low phosphorus, low-sulfur and high-carbon steel of a high grade surely and economically by mixing low-phosphorus and low-sulfur iron at a proper amt. with refined low phosphorus, low sulfur and low carbon steel. CONSTITUTION:The molten iron C obtd. in a blast furnace BF is treated with dephosphorizing and desulfurizing agents of soda ash or lime to obtain molten iron C-1. The iron C-1 is charged into a converter 2, where a flux 3 is added thereto and the molten iron is subjected to blowing under ordinary conditions, whereby the molten steel C-2 of low phosphorus, low sulfur and low carbon is obtained. The steel C-2 is transferred into a mixing pan 4, where a disoxidizing agent 5 is charged thereto, whereby molten steel C-3 is obtained. On the other hand, the molten iron C of low phosphorus, low sulfur and high carbon obtd. by dephosphorization and desulfurization of the other molten iron C' by the method similar to the above-mentioned method is added to the steel C-3 in said pan 4 and both are mixed, whereby molten steel C-5 of low phosphorus, low sulfur and high carbon is obtained. Thereafter, a product C-6 is obtained by the processes similar to those in the prior art. The product C-6 is the low- phosphorus, low-sulfur and high-carbon steel contg., for example, 0.72% C, 0.25% Si, 0.65% Mn, 0.005% P, and 0.005% S. |
