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CN-122012844-A - Method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of converter

CN122012844ACN 122012844 ACN122012844 ACN 122012844ACN-122012844-A

Abstract

The invention provides a method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of a converter, which belongs to the technical field of oxygen converter steelmaking and comprises the steps of inputting molten iron components and temperature into a thermal balance calculation model system before smelting, and loading the calculated scrap steel and the calculated low-silicon high-temperature molten iron into the converter according to the calculated scrap steel and the calculated molten iron amount. And adding a first batch of slag forming materials at the same time of blowing, wherein lime, light burned dolomite and cold pressed iron sheet balls are added according to 50 percent, dolomite is added according to 100 percent, and when the oxygen blowing amount is 20-25 percent of the total oxygen blowing amount, the rest metallurgical lime and light burned dolomite are added. Slag charge consumption, namely 22-25 kg of lime ton steel, 18-24 kg of light burned dolomite ton steel, 6-10 kg of dolomite ton steel and 22-24 kg of cold pressed iron ball ton steel. The invention solves the problems of difficult slag formation and low dephosphorization rate of high-quality carbon strip steel smelted by low-silicon high-temperature molten iron of the converter.

Inventors

  • LIU ZUOJIN
  • YU TAO
  • LI FUSHENG
  • LIU BAOXI
  • Ping Fenglei
  • CHENG YUHAN

Assignees

  • 河北安丰钢铁集团有限公司

Dates

Publication Date
20260512
Application Date
20260310

Claims (10)

  1. 1. A method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of a converter is characterized by comprising the following steps: Before smelting, inputting molten iron components and temperature into a thermal balance calculation model, and filling the molten iron into the molten iron according to the calculated amount of the molten iron and the molten steel, wherein the silicon content in the molten iron is reduced to 0.08-0.20%, and the temperature is raised to more than or equal to 1400 ℃; The converter slag-forming auxiliary materials comprise metallurgical quicklime, light-burned dolomite, dolomite blocks and cold pressed iron balls, wherein the consumption of lime ton steel is 22-25 kg, the consumption of light-burned dolomite ton steel is 18-24 kg, the consumption of dolomite ton steel is 6-10 kg, the consumption of cold pressed iron balls ton steel is 22-24 kg, the first batch of slag-forming materials are added during start blowing, the lime, light-burned dolomite and cold pressed iron balls are all added according to 50% and 100% of dolomite, the early-stage temperature is controlled below 1470 ℃ carbon-oxygen reaction temperature line, when the oxygen blowing amount is 20-25% of the total oxygen supply amount, the rest metallurgical lime and light-burned dolomite are added, the rest cold pressed iron balls are added in batches in the middle of blowing, and the temperature of a molten pool is controlled to be uniformly increased.
  2. 2. The method for smelting high-quality carbon strip steel by using converter low-silicon high-temperature molten iron is characterized by comprising the following components, by mass, 4.4-5.2% of C, 0.08-0.20% of Si, 0.20-0.30% of Mn, 0.10-0.15% of P, 0.010-0.020% of S, and the balance of Fe and unavoidable impurities, wherein the temperature of the molten iron is 1405 ℃.
  3. 3. The method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of a converter as claimed in claim 1, wherein the component mass percentage of the cold-pressed iron sheet balls is ：TFe：45.0~50.0;C：5.0~7.0;CaO：12.0~16.0;MgO：3.0~6.0;SiO 2 ：4.0~7.0;Al 2 O 3 ：≤1.60;S≤0.10;P≤0.10;H 2 O≤0.5; and the compressive strength is more than or equal to 55MPa.
  4. 4. The method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of a converter as set forth in claim 3, wherein the method for preparing the cold-pressed iron ball comprises the following steps: the raw materials are selected from iron scale, high-grade steel slag magnetic separation powder, converter dust and limestone powder, the mixture ratio is carried out according to the component requirements of the cold-pressed iron scale balls, a binder is added at room temperature, and the mixture is pressed, so that the grain size is controlled according to 25 mm.
  5. 5. The method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of a converter as set forth in claim 1, wherein the thermal balance calculation model is hi+hg-Hc-h1=hr, and wherein: Hi is heat brought by molten iron in kilojoules, hg is heat of chemical reaction of molten iron in kilojoules, hc is heat consumed by adding slag and alloy materials in kilojoules, H1 is heat contained in molten steel and steel slag in kilojoules, hr is heat consumed by scrap steel and coolant in kilojoules.
  6. 6. The method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron in a converter as claimed in claim 1, wherein the step of adding the rest of cold-pressed iron balls in batches comprises the following steps: and adding the rest cold pressed iron balls into 2-3 batches in small batches.
  7. 7. The method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of a converter according to claim 1, wherein the oxygen flow rate in the early stage of blowing is 632Nm 3 /min, the lance position of an oxygen lance is controlled within the range of 1.8-2.0 m, and the oxygen supply is controlled to be 25-35% of the total oxygen supply.
  8. 8. The method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of a converter according to claim 1, wherein the oxygen flow rate in the middle of converting is 570Nm 3 /min, the lance position of an oxygen lance is controlled within the range of 1.9-2.1 m, and the oxygen supply is controlled to be 45-55% of the total oxygen supply.
  9. 9. The method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of a converter according to claim 1, wherein the oxygen flow rate in the later period of blowing is 632Nm 3 /min, the lance position of an oxygen lance is controlled within the range of 1.8-2.0 m, the final lance pressing time is more than or equal to 40S, and the oxygen supply is controlled to be 10-15% of the total oxygen supply.
  10. 10. A carbon strip steel obtained by the method for smelting high-quality carbon strip steel by using the converter low-silicon high-temperature molten iron according to any one of claims 1 to 9.

Description

Method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of converter Technical Field The invention belongs to the technical field of oxygen converter steelmaking, and particularly relates to a method for smelting high-quality carbon strip steel by using low-silicon high-temperature molten iron of a converter, which is mainly used for smelting carbon strip steel by using low-silicon high-temperature molten iron of a large-sized and medium-sized converter. Background The conventional converter steelmaking process mainly comprises the steps of steelmaking preparation, charging, converting and tapping, wherein the converting process is generally divided into three stages of a front stage (a silicomanganese oxidation stage), a middle stage (a carbon-oxygen reaction stage) and a rear stage (a component temperature adjustment stage). The process is suitable for molten iron smelting with the silicon content of 0.20-0.40% and the temperature of less than or equal to 1250 ℃ for a long time, and realizes better technical and economic indexes by regulating parameters such as oxygen flow, oxygen lance position, slag forming material proportion and the like. However, with the development of the modern blast furnace ironmaking technology, the low-silicon smelting technology of molten iron, the transportation distance shortening, the one-tank bottom and the ladle capping technology are widely applied to blast furnace ironmaking, and the physical heat loss is reduced, so that the low-silicon high-temperature molten iron is in a normal state. The silicon content of molten iron received by the converter is obviously reduced to 0.08-0.20%, and the temperature is increased to be more than or equal to 1400 ℃, so that the traditional process faces serious challenges. The silicon content in molten iron is reduced, the SiO 2 content generated by the oxidation reaction of molten iron and silicon in the converter blowing process is obviously reduced, the contents of tricalcium silicate and dicalcium silicate generated when the lime addition amount is unchanged are increased, and the melting temperature of tricalcium silicate and dicalcium silicate is high, so that the melting temperature of slag is increased, the fluidity is poor, meanwhile, the temperature of molten iron is high, the temperature of a molten pool is increased to trigger a carbon-oxygen reaction temperature line 1470 ℃ to reduce the iron oxide content in slag, the melting of lime is unfavorable, the converter slag melting is difficult, the slag melting of the converter is difficult, the foaming degree of the slag is reduced due to the converter slag melting difficulty, metal splashing frequently occurs, the waste steel is more easily caused by the waste steel after the rising, and the slag melting difficulty causes the problems of oxygen sticking gun, furnace mouth sticking, smoke sticking hood, dephosphorization difficulty and the like. The metal splash causes various consumption increase, the waste steel postization affects the uniformity and stability of the component temperature, the oxygen lance, the furnace mouth and the smoke hood are adhered not only against the clean production concept, but also are extremely easy to cause equipment or safety accidents, the dephosphorization rate is reduced, and the difficulty of producing high-quality steel is increased. In the prior art, although the slag melting problem can be partially improved by adjusting the parameters of an oxygen lance, adding serpentine or adopting low oxygen flow and other methods, the problems of slag forming mechanism and process suitability in the low-silicon high-temperature molten iron smelting process cannot be systematically solved, and particularly, an effective solution is lacking in aiming at the production requirements of high-quality carbon strip steel. Disclosure of Invention In view of the above, the invention aims to provide a method for converting high-quality carbon strip steel by converter low-silicon high-temperature molten iron, which is based on heat balance calculation, improves slag melting route and mechanism, promotes early slag melting, reduces metal splash and achieves higher dephosphorization rate, and meets the standard requirements of high-quality steel. The invention solves the problems of difficult slag formation and low dephosphorization rate of high-quality carbon strip steel smelted by low-silicon high-temperature molten iron of the converter. Meanwhile, cold-pressed iron sheet balls with cooling and slag melting functions are developed, so that metal splashing is reduced, and steel material consumption is reduced by 2kg/t. In order to achieve the above purpose, the present invention provides the following technical solutions: On the one hand, the invention provides a method for converting high-quality carbon steel by using low-silicon high-temperature molten iron of a converter, which comprises the following steps: (1