Method for efficiently producing ultra-low phosphorus steel at low cost

The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a low-cost and high-efficiency method for producing ultra-low phosphorus steel, which adopts a brand-new process of converter, after-furnace stirring dephosphorization and after-furnace ladle replacement for production, the smelting of ultra-low phosphorus molten steel does not need three-removal, no special requirements on the temperature and components of the molten iron exist, the physical heat loss of the molten iron is small, the temperature of the molten iron entering the furnace is high, and the production cost is low. In the converter blowing process, the loss of steel and iron materials and alloy is small, the removal time of oxidizing top slag behind the converter is shorter than the converter smelting period, continuous and stable production is facilitated, the phosphorus content hit rate is high, continuous, low-cost, efficient and stable production of ultra-low phosphorus steel can be achieved, and pow