Method for smelting high-quality carbon strip steel from converter low-silicon high-temperature molten iron

Abstract

The invention provides a method for smelting high-quality carbon strip steel from converter low-silicon high-temperature molten iron, which belongs to the technical field of oxygen converter steelmaking, and comprises the following steps: before smelting, inputting the components and temperature of molten iron into a heat balance calculation model system, and filling scrap steel and low-silicon high-temperature molten iron according to the calculated quantity of the scrap steel and the molten iron. A first batch of slagging materials is added while blowing is started, 50% of lime, 50% of light-burned dolomite and 50% of cold-pressed iron balls are added, and 100% of dolomite is added; and when the oxygen blowing amount is 20%-25% of the total oxygen supply amount, adding the rest metallurgical lime and light-burned dolomite. And slag charge consumption: 22-25 kg of lime is consumed per ton of steel, 18-24 kg of light-burned dolomite is consumed per ton of steel, 6-10 kg of dolomite is consumed per ton of steel, and 22-24 kg of cold-pressed iron ball is consumed per ton of steel. The method solves the problems of difficult slagging and low dephosphorization rate in smelting of high-quality carbon strip steel from low-silicon high-temperature molten iron in the converter.

Description

Technical Field

[0001] This invention belongs to the field of oxygen converter steelmaking technology, and in particular relates to a method for smelting high-quality carbon strip steel with low-silicon high-temperature molten iron in a converter. It is mainly used for smelting carbon strip steel with low-silicon high-temperature molten iron in large and medium-sized converters. Background Technology

[0002] Traditional converter steelmaking processes mainly include steelmaking preparation, charging, blowing, and tapping. The blowing process is typically divided into three stages: the early stage (silicon-manganese oxidation period), the middle stage (carbon-oxygen reaction period), and the late stage (composition and temperature adjustment period). This process has long been suitable for smelting molten iron with a silicon content of 0.20-0.40% and a temperature ≤1250℃. By controlling parameters such as oxygen flow rate, oxygen lance position, and slag-forming material ratio, good technical and economic indicators have been achieved.

[0003] However, with the development of modern blast furnace ironmaking technology, low-silicon smelting technology, shortened transport distances, single-ladle pouring, and ladle covering technologies have been widely applied in blast furnace ironmaking, reducing physical heat loss and making low-silicon, high-temperature molten iron the norm. The silicon content of molten iron received by converters has been significantly reduced to 0.08~0.20%, and the temperature has been increased to ≥1400℃, which poses a serious challenge to traditional processes.

[0004] Because the silicon content in the molten iron decreases, the SiO2 content generated by the oxidation reaction of silicon in the molten iron during converter blowing is significantly reduced. With a constant amount of lime added, the content of tricalcium silicate and dicalcium silicate increases. Since tricalcium silicate and dicalcium silicate have high melting temperatures, the melting temperature of the slag increases, resulting in poorer fluidity. Simultaneously, the high temperature of the molten iron raises the molten pool temperature, triggering the carbon-oxygen reaction temperature line of 1470℃, reducing the iron oxide content in the slag, which is detrimental to lime melting and also makes slagging in the converter difficult. Due to the difficulty in slagging in the converter, the degree of slag foaming decreases, leading to frequent metal splashing. The increased scrap ratio easily causes post-slag processing during steelmaking, and the difficulty in slagging results in problems such as oxygen lance sticking, furnace mouth sticking, fume hood sticking, and dephosphorization difficulties. Metal splashing increases various consumptions; post-slag processing affects the uniformity and stability of composition and temperature; oxygen lance sticking, furnace mouth sticking, and fume hood sticking not only violate the concept of clean production but also easily cause equipment or safety accidents; the reduced dephosphorization rate increases the difficulty of producing high-quality steel.

[0005] Existing technologies, such as adjusting oxygen lance parameters, adding serpentine, or using low oxygen flow rates, can partially improve slag formation, but none of them can systematically solve the slag formation mechanism and process adaptability issues in the smelting of low-silicon high-temperature molten iron, especially lacking effective solutions for the production needs of high-quality carbon strip steel. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method for smelting high-quality carbon strip steel using low-silicon, high-temperature molten iron in a converter. Based on heat balance calculations, the method improves the slag formation process and mechanism, promotes early-stage slag formation, reduces metal splashing, and achieves a higher dephosphorization rate, meeting the requirements of high-quality steel standards. This invention solves the problems of difficult slag formation and low dephosphorization rate in smelting high-quality carbon strip steel using low-silicon, high-temperature molten iron in a converter. Simultaneously, a cold-pressed iron ball with both cooling and slag-forming functions is developed, reducing metal splashing and lowering steel material consumption by 2 kg / t.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] On one hand, the present invention provides a method for blowing high-quality carbon steel from low-silicon, high-temperature molten iron in a converter, comprising the following steps: (1) Before smelting begins, the composition and temperature of the molten iron are input into the heat balance calculation model, and scrap steel and low-silicon high-temperature molten iron are loaded according to the calculated amount of scrap steel and molten iron.

[0009] (2) Early stage of blowing (silicon-manganese oxidation period, 3-5 min after blowing starts): oxygen flow rate is 632 Nm³. 3 The oxygen lance position is controlled within the range of 1.8~2.0m, and the oxygen supply is controlled to be 25~35% of the total oxygen supply. The converter slag-forming auxiliary materials are metallurgical quicklime, light-burned dolomite, dolomite blocks, and cold-pressed iron balls. The consumption of quicklime per ton of steel is 22~25kg, light-burned dolomite per ton of steel is 18~24kg, dolomite per ton of steel is 6~10kg, and cold-pressed iron balls per ton of steel is 22~24kg. The first batch of slag-forming materials is added at the same time as the blowing starts, with quicklime, light-burned dolomite, and cold-pressed iron balls added at a ratio of 50%, and dolomite added at a ratio of 100%. When the oxygen blowing rate is 20~25% of the total oxygen supply, the remaining metallurgical quicklime and light-burned dolomite are added. By increasing the magnesium oxide content in the slag, the slag formation pathway is altered, generating calcium magnesium olivine with a lower melting point to replace tricalcium silicate and dicalcium silicate with higher melting points. In addition, cold-pressed iron balls, which use steel slag magnetic separation as the main raw material, contain steel slag as an impurity component, resulting in a significant slag-forming effect. The decomposition and heat absorption of dolomite blocks help to reduce the initial heating rate and avoid prematurely triggering the carbon-oxygen reaction temperature of 1470℃, thus ensuring the (FeO) content in the slag. As a result, the melting point of the slag is lowered, its fluidity is improved, and metal splashing is reduced.

[0010] (3) Mid-stage of blowing (carbon-oxygen reaction period, 6-11 min after blowing starts): oxygen flow rate is 570 Nm³. 3 The oxygen lance position is controlled within the range of 1.9~2.1m, and the oxygen supply is controlled to be 45~55% of the total oxygen supply. The remaining cold-pressed iron balls are added in small batches to control the temperature of the molten pool to rise evenly, thereby controlling the carbon-oxygen reaction to proceed smoothly and avoiding mid-term splashing. The residual components of the cold-pressed iron balls help to replenish the slag (FeO) consumed by the carbon-oxygen reaction, preventing the slag from "drying up" and reducing metal splashing.

[0011] (4) Late stage of blowing (composition and temperature adjustment period, 12-16 min after blowing starts): oxygen flow rate is 632 Nm³. 3 / min, the oxygen lance position is controlled within the range of 1.8~2.0m, the final lance pressing time is ≥40S, and the oxygen supply is controlled to be 10~15% of the total oxygen supply; 2 minutes before stopping blowing, the auxiliary lance equipped with a probe measures the temperature and takes a sample, and the endpoint is predicted using dynamic model technology, with adjustment and homogenization of composition and temperature as the main characteristics.

[0012] (5) Tapping: When the actual oxygen supply reaches the oxygen target calculated by the converter dynamic model, the blowing is stopped by raising the lance, the temperature is measured and sampled by the lower auxiliary lance, and when the composition and temperature meet the requirements for steel casting, the converter is tilted to tap the steel, thus completing the blowing of a heat of steel.

[0013] The composition by mass percentage of the above-mentioned low-silicon high-temperature molten iron is as follows: C: 4.4~5.2; Si: 0.08~0.20; Mn: 0.20~0.30; P: 0.10~0.15; S: 0.010~0.020; the remainder is Fe and unavoidable impurities; the molten iron temperature is 1405℃.

[0014] The composition (by mass percentage) of the cold-pressed iron ball is as follows: TFe: 45.0~50.0; C: 5.0~7.0; CaO: 12.0~16.0; MgO: 3.0~6.0; SiO2: 4.0~7.0; Al2O3: ≤1.60; S≤0.10; P≤0.10; H2O≤0.5; compressive strength ≥55MPa.

[0015] The main process controls of this invention are as follows: 1. Preparation 1) Develop a heat balance calculation model Based on the heat balance principle of converter steelmaking, a heat balance calculation model suitable for converter blowing of low-silicon high-temperature molten iron was developed: Hi + Hg - Hc - H1 = Hr; where: Hi: Input heat, heat brought in by molten iron, kJ; Hg: Heat generated, heat of chemical reaction, kJ; Hc: Heat consumed, heat consumed when adding slag or alloy materials, kJ; H1: Stored heat, the heat contained in molten steel and slag, in kJ; Hr: Excess heat, the heat consumed by scrap steel and coolant, in kJ.

[0016] This calculation model takes the composition and temperature of molten iron as inputs, the chemical and physical changes that occur between molten iron and molten steel as the basis, the physical and chemical heat of molten iron as the heat input, and the physical and chemical heat of molten steel, steel slag, flue gas, and dust as the heat output. Using thermodynamic functions, the iron ratio, scrap steel ratio, and coolant usage for each heat of steel can be accurately calculated.

[0017] According to the heat balance model, when the converter is used to blow low-silicon high-temperature molten iron, the scrap steel ratio increases by 2 to 4 percentage points, the process equipment remains stable, and equipment modification, large-scale process adjustment and personnel training are avoided.

[0018] 2) Develop a cold-pressed iron ball Adjustments were made to the process of converter blowing low-silicon high-temperature molten iron, and the cold-pressed iron balls, which act as both coolants and slag-reducing agents, were used flexibly.

[0019] The composition of the cold-pressed iron ball is shown in Table 1.

[0020] Table 1

[0021] The preparation method of cold-pressed iron balls is as follows: the raw materials are selected from iron oxide scale, high-grade steel slag magnetic separation powder, converter dust, and limestone powder. They are proportioned according to the composition requirements of cold-pressed iron balls, and a binder is added at room temperature and pressed into balls. The particle size is controlled at 25mm.

[0022] 2. Process parameter control: Process flow: Steelmaking preparation (calculation of heat balance model for main raw materials and auxiliary materials) — Charging (loading scrap steel first, then molten iron) — Blowing (early blowing, middle blowing, and late blowing) — Tapping. This invention represents a significant improvement over existing technologies in steelmaking preparation, slag formation, and temperature control.

[0023] Steelmaking preparation: Considering the difficulty of slag formation in the early stage of low-silicon high-temperature molten iron blowing, and in order to prevent metal splashing and reduced dephosphorization rate caused by slag non-dissolving in the early stage of blowing, the scrap steel ratio is increased by 2-4% through heat balance model calculation to avoid prematurely triggering the carbon-oxygen reaction temperature of 1470℃, suppressing excessive consumption of (FeO) in the slag, and promoting slag formation.

[0024] Slag-forming process: Considering the difficulty of slag formation in the early stage of high-temperature, low-silicon iron blowing, firstly, dolomite blocks and cold-pressed iron balls were added to the slag-forming materials. Their decomposition endothermic process helps to slow down the temperature rise in the early stage of blowing. Secondly, the (MgO) produced by the decomposition of dolomite will generate low-melting-point calcium magnesium olivine, avoiding the high-melting-point dicalcium silicate and tricalcium silicate, thus changing the slag formation route. In addition, the approximately 40-50% residual components of the cold-pressed iron balls, excluding iron, are mainly similar to steel slag, resulting in a significant slag-forming effect. The specific dosages are: metallurgical lime 22-25 kg per ton of steel, lightly calcined dolomite 18-24 kg per ton of steel, dolomite blocks 6-10 kg per ton of steel, and cold-pressed iron balls 22-24 kg per ton of steel.

[0025] Temperature regime: Dephosphorization and desulfurization are among the main tasks in the smelting of high-quality carbon strip steel using low-silicon, high-temperature molten iron in a converter. To address the high temperature issue of the molten iron, the first batch of slag-forming materials is added simultaneously with the start-up blowing: lime, lightly calcined dolomite, and cold-pressed iron balls are added at a ratio of 50%, with dolomite added at 100%, controlling the initial temperature below the carbon-oxygen reaction temperature line of 1470℃. During the middle stage of blowing, the remaining cold-pressed iron balls are added in small batches of 2-3 times to control the uniform rise of the molten pool temperature, thereby controlling the carbon-oxygen reaction to proceed smoothly and avoiding mid-stage splashing. The residual components of the cold-pressed iron balls help replenish the slag (FeO) consumed in the carbon-oxygen reaction, preventing the slag from "drying out" and reducing metal splashing. In the later stage of blowing, the lance pressing time before tapping is ≥40s to ensure uniform composition and temperature.

[0026] Compared with the prior art, the advantages of the present invention are as follows: (1) The present invention adjusts the amount of raw (auxiliary) materials entering the furnace through a heat balance calculation model, and realizes the heat balance between income and expenditure, laying the foundation for improving slag formation in the early stage of blowing.

[0027] (2) By changing the slag structure, the production of low-melting-point calcium magnesium olivine bypasses the high-melting-point tricalcium silicate and dicalcium silicate slag formation routes, thereby reducing equipment investment and process adjustments.

[0028] (3) By adding cold-pressed iron balls in batches and optimizing the slag formation and temperature system, this invention improves the slag formation of low-silicon high-temperature molten iron in converter smelting. In the early stage of converter blowing, slag can be formed quickly. In the middle stage of blowing, the slag "re-drying" is reduced. The degree of foaming of slag is improved, and phenomena such as sticking to oxygen lance, sticking to furnace mouth, and sticking to smoke hood are reduced. The dephosphorization rate is improved, and the hit rate of producing high-quality steel is increased.

[0029] (4) Reduced metal splashing in converter, temperature control of cold-pressed iron ball, reduced steel material consumption per ton of steel by 2kg, resulting in an annual increase in efficiency of RMB4 million. Detailed Implementation

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0032] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0033] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0034] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0035] Example 1: S1. Raw material preparation: Iron molten metal conditions: C: 5.0%, Si: 0.10%, Mn: 0.30%, P: 0.14%, S: 0.02%, iron molten metal temperature 1405℃.

[0036] The amount of molten iron to be charged is determined, and the composition and temperature of the molten iron are input into the heat balance calculation model to calculate the amount of scrap steel and converter slag-forming auxiliary materials used under this amount of molten iron. In this embodiment, the amounts of molten iron (137t), scrap steel (28.32t), metallurgical lime (3.01t), lightly calcined dolomite (2.47t), dolomite (0.96t), and cold-pressed iron balls (3.15t) are used.

[0037] S2. Loading: According to the calculated amounts of molten iron and scrap steel, load the scrap steel first, then load the molten iron.

[0038] S3, Blowing: The oxygen lance is controlled using a constant pressure variable lance method, with the initial lance position at 1.8m and the flow rate at 583Nm³. 3 / min; process gun position 1.9-2.0m, slag-forming gun position 2.1-2.2m, flow rate 533Nm 3 / min; later carbon drawing gun position 1.8m, flow rate 583Nm 3 / min; 40s of gun-pressing time before the finish line.

[0039] The binary basicity is set at 5.8. The slag addition amounts are: 22 kg / t lime, 18 kg / t lightly calcined dolomite, 7 kg / t dolomite, and 23 kg / t cold-pressed iron balls. The first batch of slag includes lime, lightly calcined dolomite, 50% of the cold-pressed iron balls, and 100% of the dolomite. The remainder is added in three batches to reduce the final carbon content to 0.08%. One minute before lifting the lance, 120 kg of cold-pressed iron balls is added. It should be noted that the unit "kg / t" for slag addition refers to the amount of molten iron charged per ton.

[0040] S4. Tapping: When the actual oxygen supply reaches the oxygen target calculated by the converter dynamic model, the lance is lifted and blowing stops. The converter oxygen blowing time is 13.2 minutes.

[0041] Temperature sampling was performed on the lower secondary gun. Measured composition and temperature: C: 0.047%, Mn: 0.015%, P: 0.016%, S: 0.012%. Stop blowing temperature: 1642℃.

[0042] This embodiment, by adopting a high binary basicity design of 5.8 and a charging ratio of 137t of molten iron and 28.32t of scrap steel, achieved a good dephosphorization effect with a final phosphorus content of 0.016% under the condition that the silicon content of molten iron is only 0.10%, while accurately controlling the final carbon content at 0.047% and stabilizing the tapping temperature at 1642℃. It is particularly suitable for the production of ultra-low carbon steel grades, and the slag system has high stability, effectively reducing the risk of splashing during the smelting process.

[0043] Example 2: S1. Raw material preparation: Iron molten metal conditions: C: 4.8%, Si: 0.20%, Mn: 0.30%, P: 0.15%, S: 0.025%, iron molten metal temperature 1398℃.

[0044] The amount of molten iron to be charged is determined, and the composition and temperature of the molten iron are input into the heat balance calculation model to calculate the amount of scrap steel and converter slag-forming auxiliary materials used under this amount of molten iron. In this embodiment, the amounts are: 137t molten iron, 27.43t scrap steel, 3.02t metallurgical lime, 2.48t lightly calcined dolomite, 0.83t dolomite, and 3.20t cold-pressed iron balls.

[0045] S2. Loading: According to the calculated amounts of molten iron and scrap steel, load the scrap steel first, then load the molten iron.

[0046] S3, Blowing: The oxygen lance is controlled using a constant pressure variable lance method, with an initial lance position of 1.9m and a flow rate of 583Nm. 3 / min; process gun position 2.0 -2.1m, slag-forming gun position 2.1 -2.2m, flow rate 533Nm 3 / min; later carbon drawing gun position 1.8m, flow rate 583Nm 3 / min; 40s of gun-pressing time before the finish line.

[0047] The binary basicity is set at 3.5. The slag addition amounts are: lime 22.05 kg / t, lightly calcined dolomite 18.09 kg / t, dolomite 6.03 kg / t, and cold-pressed iron balls 23.37 kg / t. The first batch of slag is composed of lime, lightly calcined dolomite, 50% of the cold-pressed iron balls, and 100% of the dolomite. The remainder is added in three batches to reduce the final carbon content to 0.08%. One minute before lifting the lance, 100 kg of cold-pressed iron balls is added. It should be noted that the unit of slag addition (kg / t) refers to the amount of molten iron charged per ton.

[0048] S4. Tapping: When the actual oxygen supply reaches the oxygen target calculated by the converter dynamic model, lift the lance and stop blowing. The converter oxygen blowing time is 12.8 minutes.

[0049] Temperature sampling was performed on the lower secondary gun. Measured composition and temperature: C: 0.051%, Mn: 0.019%, P: 0.010%, S: 0.008%. Stop blowing temperature: 1635℃.

[0050] This embodiment innovatively employs a medium binary basicity of 3.5. Under the condition of 0.20% silicon content in molten iron, by optimizing the slag ratio (3.02t lime, 2.48t lightly calcined dolomite) and a short blowing process of 12.8min, it achieves excellent dephosphorization and desulfurization effects with a final phosphorus content of 0.010% and a sulfur content of 0.008%. The tapping temperature of 1635℃ is precisely controlled, and the overall smelting efficiency is improved by more than 15%, making it particularly suitable for the high-efficiency production of large batches of conventional steel grades.

[0051] Example 3: S1. Raw material preparation: Iron molten metal conditions: C: 5.2%, Si: 0.25%, Mn: 0.28%, P: 0.15%, S: 0.015%, iron molten metal temperature 1412℃.

[0052] The amount of molten iron to be charged is determined, and the composition and temperature of the molten iron are input into the heat balance calculation model to calculate the amount of scrap steel and converter slagging auxiliary materials charged under this amount of molten iron. In this embodiment, the amounts are: 138t molten iron, 28t scrap steel, 3.35t metallurgical lime, 2.52t lightly calcined dolomite, 1.14t dolomite, and 3.29t cold-pressed iron balls.

[0053] S2. Loading: According to the calculated amounts of molten iron and scrap steel, load the scrap steel first, then load the molten iron.

[0054] S3, Blowing: The oxygen lance is controlled using a constant pressure variable lance method, with an initial lance position of 1.9m and a flow rate of 583Nm. 3 / min; process gun position 2.0 -2.1m, slag-forming gun position 2.1 -2.2m, flow rate 533Nm 3 / min; later carbon drawing gun position 1.8m, flow rate 583Nm 3 / min; 40s of gun-pressing time before the finish line.

[0055] The binary basicity is set at 3.0. The slag addition amounts are: lime 24.3 kg / t, lightly calcined dolomite 18.29 kg / t, dolomite 8.23 ​​kg / t, and cold-pressed iron balls 23.83 kg / t. The first batch of slag is composed of lime, lightly calcined dolomite, 50% of the cold-pressed iron balls, and 100% of the dolomite. The remainder is added in three batches to reduce the final carbon content to 0.08%. One minute before lifting the lance, 100 kg of cold-pressed iron balls is added. It should be noted that the unit "kg / t" for slag addition refers to the amount of molten iron charged per ton.

[0056] S4. Tapping: When the actual oxygen supply reaches the oxygen target calculated by the converter dynamic model, the lance is lifted and blowing stops. The converter oxygen blowing time is 13.4 min.

[0057] Temperature sampling was performed on the lower secondary gun. Measured composition and temperature: C: 0.047%, Mn: 0.018%, P: 0.012%, S: 0.009%. Stop blowing temperature: 1638℃.

[0058] This embodiment, designed for molten iron with a silicon content as high as 0.25%, creatively employs a low binary basicity of 3.0 combined with a high lime content of 3.35t. While ensuring a final phosphorus content of 0.012%, the addition of 1.14t dolomite effectively protects the furnace lining. A blowing time of 13.4min achieves a final carbon content of 0.047% and a tapping temperature of 1638℃. This method is particularly suitable for smelting high-silicon molten iron and extends the service life of the converter.

[0059] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for smelting high-quality carbon strip steel in a converter with low-silicon, high-temperature molten iron, characterized in that, include: Before smelting begins, the composition and temperature of the molten iron are input into the heat balance calculation model, and scrap steel and low-silicon high-temperature molten iron are loaded according to the calculated amount of scrap steel and molten iron. The silicon content in low-silicon high-temperature molten iron is reduced to 0.08~0.20%, and the temperature is increased to ≥1400℃; The converter slag-forming auxiliary materials are metallurgical quicklime, light-burned dolomite, dolomite blocks, and cold-pressed iron balls. The consumption of quicklime is 22-25 kg per ton of steel, light-burned dolomite is 18-24 kg per ton of steel, dolomite is 6-10 kg per ton of steel, and cold-pressed iron balls are 22-24 kg per ton of steel. The first batch of slag-forming materials is added at the start of blowing, with quicklime, light-burned dolomite, and cold-pressed iron balls added at a ratio of 50%, and dolomite added at 100%, to control the initial temperature below the carbon-oxygen reaction temperature line of 1470℃. When the oxygen blowing rate is 20-25% of the total oxygen supply, the remaining metallurgical quicklime and light-burned dolomite are added. During the middle stage of blowing, the remaining cold-pressed iron balls are added in small batches to control the uniform rise of the molten pool temperature.

2. The method for smelting high-quality carbon strip steel in a converter with low-silicon high-temperature molten iron according to claim 1, characterized in that, The mass percentage composition of the low-silicon high-temperature molten iron is: C: 4.4~5.2; Si: 0.08~0.20; Mn: 0.20~0.30; P：0.10~0.15； S: 0.010~0.020; the remainder is Fe and unavoidable impurities; The temperature of the molten iron was 1405℃.

3. The method for smelting high-quality carbon strip steel in a converter with low-silicon high-temperature molten iron according to claim 1, characterized in that, The cold-pressed iron ball has the following composition by mass percentage: TFe: 45.0~50.0; C：5.0~7.0； CaO: 12.0~16.0; MgO: 3.0~6.0; SiO2: 4.0~7.0; Al2O3: ≤1.60; S≤0.10; P≤0.10; H2O≤0.5; Compressive strength ≥55MPa.

4. The method for smelting high-quality carbon strip steel in a converter with low-silicon high-temperature molten iron according to claim 3, characterized in that, The method for preparing the cold-pressed iron ball includes: The raw materials are selected from iron oxide scale, high-grade steel slag magnetic separation powder, converter dust, and limestone powder. They are proportioned according to the composition requirements of the cold-pressed iron sheet balls, and a binder is added and pressed at room temperature. The particle size is controlled at 25mm.

5. The method for smelting high-quality carbon strip steel in a converter with low-silicon high-temperature molten iron according to claim 1, characterized in that, The heat balance calculation model is: Hi + Hg - Hc - H1 = Hr; where: Hi represents the heat introduced by the molten iron, measured in kilojoules (kJ); Hg represents the heat of chemical reaction in the molten iron, measured in kJ; Hc represents the heat consumed by the addition of slag and alloy materials, measured in kJ; H1 represents the heat contained in the molten steel and steel slag, measured in kJ; and Hr represents the heat consumed by scrap steel and coolant, measured in kJ.

6. The method for smelting high-quality carbon strip steel in a converter with low-silicon high-temperature molten iron according to claim 1, characterized in that, The remaining cold-pressed iron balls were added in small batches, including: Add the remaining cold-pressed iron balls in small batches of 2-3 batches.

7. The method for smelting high-quality carbon strip steel in a converter with low-silicon high-temperature molten iron according to claim 1, characterized in that, The oxygen flow rate during the initial blowing stage was 632 Nm. 3 The oxygen lance position is controlled within the range of 1.8~2.0m, and the oxygen supply is controlled to be 25~35% of the total oxygen supply.

8. The method for smelting high-quality carbon strip steel in a converter with low-silicon high-temperature molten iron according to claim 1, characterized in that, The oxygen flow rate during the mid-stage of the blowing process was 570 Nm³. 3 The oxygen lance position is controlled within the range of 1.9~2.1m, and the oxygen supply is controlled to be 45~55% of the total oxygen supply.

9. A method for smelting high-quality carbon strip steel in a converter with low-silicon high-temperature molten iron according to claim 1, characterized in that, The oxygen flow rate during the later stage of blowing was 632 Nm. 3 / min, oxygen lance position controlled within the range of 1.8~2.0m, final lance pressing time ≥40S, and oxygen supply controlled at 10~15% of the total oxygen supply.

10. A carbon strip steel obtained by smelting high-quality carbon strip steel using low-silicon high-temperature molten iron in a converter as described in any one of claims 1 to 9.

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