Method for smelting free-cutting steel at low cost by using converter oxidizing slag

Abstract

The invention relates to a method for smelting free-cutting steel at low cost by using converter oxidizing slag, which comprises the following steps: (1) smelting in a converter to obtain molten steel with high sulfur content and high phosphorus content, and the tapping condition is that tapping C is less than or equal to 0.04%; (2) a deoxidizing agent is not used during converter tapping, molten steel is poured into a steel ladle, silicon-manganese alloy, ferrous sulfide, ferrophosphorus and a small amount of lime are sequentially added in the tapping process, and converter oxidizing slag is added after tapping is finished to further reduce the silicon content; and (3) hoisting the molten steel to an LF for refining through a crown block, and refining the molten steel according to the oxygen content and silicon content of the molten steel to obtain refined molten steel. The method can further reduce the steelmaking process cost, reduce the consumption of a steelmaking deoxidizing agent aluminum, slag is formed by using the converter slag, deoxidation alloying is carried out by using a cheap silicon-manganese alloy, and meanwhile, the silicon element content meets the steel grade requirement, so that the product competitiveness can be improved; and the hot-state converter oxidizing slag is further effectively utilized.