Converter steelmaking phosphorus reservation smelting method

Abstract

The invention relates to a converter steelmaking phosphorus reservation smelting method and belongs to the technical field of metallurgy. According to the converter steelmaking phosphorus reservation smelting method, a smelting period is divided into a front state, a middle state and a late stage. By controlling an addition amount of lime, R binary basicity of cinders is constantly kept between 2.0 and 2.8. By adjusting the flow and a gun position of an oxygen ejecting gun, the weight ratios between ejected oxygen amounts of the front state, the middle state and the late stage and the total oxygen ejecting amount are respectively controlled at 18%-22%, 55%-65% and 18%-22%. Impact depths of oxygen ejecting currents of the early stage and the middle stage are controlled to be 60%-70% of the depth of melted steel. The impact depth of an oxygen ejecting current of the late stage is controlled to be 70%-80% of the melted steel. Residual carbon content of terminal point smelted steel is controlled between 0.05% to 0.1%. According to the converter steelmaking phosphorus reservation smelting method, peaks of the early smelting stage and the late smelting stage are reasonably controlled with balance. Thus, the reservation rate of the phosphorus in melted iron can be 30% to 70% without addition of phosphorus-included ore so as to achieve demanded phosphorus reservation 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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