Converter high-carbon low-phosphorous end-point control metallurgy method under condition of phosphorous molten iron in blast furnace

Abstract

Disclosed is a converter high-carbon low-phosphorous end-point control metallurgy method under the condition of phosphorous molten iron in a blast furnace. The method comprises the steps that the residual slag generated after slag splashing is reserved, molten iron and scrap steel are fed into a converter, an oxygen lance is controlled in the distance of 1.3m after ignition is finished, top oxygen blowing operation is conducted, and bottom argon blowing operation is conducted in the whole process; iron ore and lime are added to the converter, the turning-down temperature in the early period ranges from 1350DEG C to 1400DEG C, and the slag basicity in the early period ranges from 1.6 to 2.0; when the oxygen blowing quantity is 10%-15% of the total oxygen quantity, the oxygen lance is located in the distance of 1.5m-1.8m; when the oxygen blowing quantity is 30%-50% of the total oxygen quantity, slag generated in the early period is poured, the oxygen lance is located in the distance of 1.5m-2.3m, top oxygen blowing operation is conducted, bottom argon blowing operation is conducted in the whole process, lime is added to the converter to enable the final slag basicity to range from 3.2 to 3.4, and addition of the iron ore and the lime is accomplished before the oxygen blowing quantity is 75% of the total oxygen quantity; and when the oxygen blowing quantity is 85%-90% of the total oxygen quantity, the oxygen lance is located in the distance of being larger than or equal to 1.5m, and turning-down operation is conducted, when the content of carbon in molten steel is larger than 0.50% and the temperature is larger than or equal to 1580DEG C, oxygen blowing operation continues, and oxygen is blown to the molten steel, when [C] is larger than or equal to 0.30%, [P] is smaller than or equal to 0.013% and the temperature ranges from 1580DEG C to 1600DEG C, hot ladle tapping is conducted, and when tapping is conducted, aluminum iron alloy is added to a ladle to conduct deoxidization. The quality of the molten steel for hot rolled plates is ensured.

Description

technical field [0001] The invention relates to a method for controlling the end point composition of molten steel, in particular to a method for smelting blast furnace molten iron with a phosphorus content of 0.14% to 0.18% through a converter to produce a type of phosphorus with an end point carbon content of ≥0.3% and an end point phosphorus content of ≤0.013% in molten steel. High-carbon and low-phosphorus end-point control metallurgical method (process) of converter under the condition of high-temperature molten iron is high-carbon and low-phosphorus molten steel. Background technique [0002] At present, the high-carbon and low-phosphorus steel (material) produced by iron and steel enterprises has a carbon content of 0.30%~0.97% (wt) and a phosphorus content of ≤0.015% (wt). Considering the large amount of alloy added to molten steel The influence of phosphorus back in molten steel occurs, and the phosphorus content at the end of the molten steel in the converter is ...

AI Technical Summary

Problems solved by technology

[0003] ①Experiential steelmaking, the control of the composition of molten steel at the end point is unstable

Due to fluctuations in the amount and composition of molten steel slag, the success rate of molten steel sampling is low. This operation mode, which relies entirely on manual judgment (experience estimation), cannot guarantee the stability and control of the final composition of molten steel.

[0004] ②Single slag mode, low converter dephosphorization rate

At the same time, the end carbon of molten steel is high, and the oxidation of molten steel is low, and the dephosphorization effect of the converter cannot be guaranteed.

[0006] ④ The carbon, temperature and phosphorus at the end point of molten steel cannot be coordinated

While ensuring that the phosphorus at the end point of molten steel is qualified and avoiding the peroxidation of molten steel, the temperature of molten steel is often difficult to meet the requirements