Converter steelmaking phosphorus reservation smelting method

Abstract

The invention relates to a phosphorus-preserving smelting method for converter steelmaking, which belongs to the technical field of metallurgy. In this method, the smelting time is divided into three phases: the first, the middle, and the last. By adjusting the amount of lime added, the binary basicity R of the slag is always controlled between 2.0 and 2.8; The mass percentages of the oxygen blowing volume and the total oxygen blowing volume in the first, middle and last phases are controlled at 18-22%, 55-65%, and 18-22% respectively, and the impact depth of the oxygen jet in the early and middle phases is controlled at 100% of the depth of molten steel. 60-70%, and the impact depth of the oxygen jet in the later stage is controlled at 70-80% of the molten steel depth; the residual carbon content of the final molten steel is controlled at 0.05-0.1%. After adopting the present invention, since the peaks of dephosphorization before and after smelting are reasonably balanced and controlled, the retention rate of phosphorus in molten iron can reach 30% to 70% without adding phosphorus-containing ore, thereby realizing the required Phosphorus smelting.

Description

technical field [0001] The invention relates to a metal smelting method, in particular to a converter steelmaking and phosphorus-preserving smelting method, which belongs to the technical field of metallurgy. Background technique [0002] High-phosphorus steel generally refers to steel types with a phosphorus content of more than 0.06% in the finished molten steel, such as weathering steel is one of them. According to the applicant's knowledge, the phosphorus content of molten steel smelted by converters at home and abroad is mostly below 0.035%, and there are few steel types with a phosphorus content above 0.06%. Steel types, how to reduce the loss of phosphorus in molten iron during the smelting process and the smelting method of phosphorus conservation. [0003] Phosphorus is a harmful element in most steel types, so it is hoped that the phosphorus content of molten steel products should be as low as possible, but in steel types such as weathering steel, it is just the o...

AI Technical Summary

Problems solved by technology

[0005] 1) The control of the smelting gun position of the converter below 1.0 meters is only suitable for small converters, and it is easy to cause serious production accidents for large and medium converters

Because the depth of the molten pool of the converter above 150 tons is above 140cm, the gun position below 1.0m may cause the oxygen jet to directly contact the bottom of the furnace

[0006] 2) This method needs to add phosphate ore to the converter molten pool before and after smelting. Not only the timing of adding needs to be strictly controlled, otherwise the effect will not be achieved, but also adding a large amount of phosphorus-containing ore to the molten pool increases the amount of slag , prone to splashing, which brings difficulties to converter smelting. At the same time, the increase in the amount of slag leads to an increase in the consumption of steel materials, which increases the cost

[0007] 3) The binary basicity of the final slag is required to be controlled at 3.0 to 4.0, which will cause the loss of phosphorus in molten steel, because the requirement of conventional smelting of low-phosphorus steel when the binary basicity is controlled to be greater than 3.0 is obviously not conducive to phosphorus retention

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