A method of smelting low silicon steel

Abstract

The application discloses a low-silicon steel smelting method, which comprises the following steps: (1) molten iron after pretreatment is loaded into a converter, double-slag operation is adopted in a smelting process, a part of desilicon slag is poured out after desilicon is finished, new slag is made to decarburize, and the basicity of converter slag is controlled; (2) converter tapping is carried out, carbon powder is added into a ladle to pre-deoxidize, and manganese alloy and aluminum pills are added into the ladle to deeply deoxidize when tapping reaches a certain degree; and (3) the molten iron is loaded into an LF furnace, carbon powder is used for diffusion deoxidization of a slag surface, and high-basicity refining slag is made in a refining process. The smelting method can effectively avoid that the silicon content of the molten iron exceeds a standard in the smelting process, and continuously cast the molten iron.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steelmaking, in particular to a low-silicon steel smelting method. BACKGROUND

[0002] In the production of low-silicon steel, preventing the increase of silicon in the molten steel is a very important problem. The silicon content in the steel is required to be ≤0.03% when producing such steel, and if the silicon content exceeds the standard, the steel grade needs to be changed or even the furnace needs to be returned to stop pouring, which brings great problems to the production organization of the enterprise.

[0003] The production process of such low-silicon steel is generally converter-LF furnace-continuous casting. The molten steel needs to be deoxidized at the refining furnace station, and the deoxidizer is generally divided into silicon deoxidizer and aluminum deoxidizer. Since low-silicon steel is produced, aluminum deoxidizer is generally used for producing low-silicon steel. However, aluminum deoxidizer is a strong deoxidizer, which will react with SiO2 in the refining slag to generate Si element reduced into the molten steel, thereby causing the silicon content in the molten steel to exceed the standard, and aluminum deoxidation will generate Al2O3 inclusions, which will cause the continuous casting nozzle to be blocked when the latter is not removed sufficiently, thereby affecting the continuous casting furnace.

[0004] At present, the silicon content in the molten steel at the end of converter blowing is basically trace ([Si]<0.001%), the (SiO2) content in the converter slag is between 15% and 20%, the molten steel is not blocked well, and a certain amount of silicon is inevitably brought in by the slag material and ferroalloy, so that the silicon content in the ladle top slag is enriched. In the subsequent deoxidation, desulfurization, and inclusion removal refining of the molten steel, the (SiO2) in the ladle top slag is easily reduced to [Si] by strong reducing agents such as aluminum and enters the molten steel, thereby causing the increase of silicon in the molten steel. This makes the deoxidation, desulfurization, slag inclusion control, and silicon increase of the molten steel contradictory when producing low-silicon steel, and preventing the increase of silicon in the whole smelting process becomes the bottleneck of smelting low-silicon steel. In order to break through this restrictive bottleneck link, it is an urgent problem to develop a control process for preventing the increase of silicon in the smelting process and stabilizing the silicon content at the end of continuous casting. SUMMARY

[0005] To solve the above problems, the purpose of the present application is to provide a low-silicon steel smelting method.

[0006] Specifically, the present application is realized by the following technical scheme:

[0007] A low-silicon steel smelting method, comprising the following steps:

[0008] (1) The pretreated molten iron is loaded into the converter, and double-slag operation is adopted in the smelting process. After the desiliconizing is completed, a part of the desiliconizing slag is poured out, and then new slag is made to decarburize, so as to control the basicity of the converter slag;

[0009] (2) When tapping steel from the converter, carbon powder is added to the ladle for pre-deoxidation. When the steel reaches a certain level, manganese alloy and aluminum shot are added to the ladle for deep deoxidation.

[0010] (3) When the molten steel enters the LF furnace, carbon powder is used for diffusion deoxidation on the slag surface, and high-alkalinity refining slag is generated during the refining process.

[0011] Optionally, in step (1), the amount of slag removed after desilication is 40% to 60%.

[0012] Optionally, in step (1), the basicity of the converter slag is controlled at 3.5 to 4.5.

[0013] Optionally, in step (1), before tapping steel after the converter smelting is completed, [C]·[O] ≤ 0.0016, according to 0.15~0.20Nm 3 Bottom-blowing CO2 with a gas supply intensity of / (min·t) and stirring for 1.5 to 2.5 min.

[0014] Optionally, in step (2), the converter tapping adopts a double slag-blocking operation of slag-blocking cone and sliding plate slag-blocking, and the slag amount and slag thickness are <30mm.

[0015] Optionally, in step (2), carbon powder is added to the ladle at a rate of 0.2 to 0.3 kg / t; when 2 / 3 of the steel is tapped, manganese alloy and aluminum shot are added for deep deoxidation and the aluminum shot is ensured to be fully added when the steel is tapped from the converter.

[0016] Optionally, in step (2), when the converter taps steel, lime is added at a rate of 5-6 kg / t to form slag by impacting the tapping steel flow; after the converter taps steel, the bottom is stirred at a high flow rate for 2-3 minutes.

[0017] Optionally, in step (3), the amount of carbon powder used is 15-30 kg / furnace, and the composition of the high-alkalinity refining slag is: CaO 50%-60%, SiO2 8%-12%, Al2O3 20%-30%, MgO 6%-8%.

[0018] Optionally, in step (3), the bottom blowing intensity of the bottom blowing agitation in the refining process is 200 to 400 L / min.

[0019] Optionally, in step (3), soft stirring is performed before tapping the steel, with a bottom blowing intensity of 50-100 L / min and a soft stirring time of >10 min.

[0020] As can be seen from the above technical solution, the low-silicon steel smelting method of the present invention has at least the following beneficial effects:

[0021] 1. The smelting method of the present invention uses a double-slag operation in the converter to produce high-basicity slag, thereby reducing the SiO2 content in the converter slag. The double-slag-blocking operation is adopted when tapping steel from the converter, which reduces the amount of slag discharged from the converter and avoids excessive Si content caused by aluminum reduction (SiO2) during the LF refining process.

[0022] 2. The converter uses carbon particle pre-deoxidation and the LF uses carbon powder deoxidation. The product is CO2 gas, which does not pollute the molten steel and is beneficial to the foaming of steel slag and the reaction between slag and steel.

[0023] 3. Adding aluminum in one go during converter tapping enables Al2O3 to be generated and floated ahead of time, increasing the time for inclusion removal. LF controls the stirring intensity appropriately to avoid secondary oxidation of Al caused by excessive stirring.

[0024] 4. The low-silicon steel produced by this method does not increase silicon during the LF smelting process, eliminates calcium treatment, and does not clog the nozzle during the continuous casting process, thereby improving the quality of the steel and reducing smelting costs. Detailed Implementation

[0025] To fully understand the purpose, features, and effects of this invention, the following detailed embodiments are provided. Except as described below, the process methods of this invention employ conventional methods or apparatus in the art. Unless otherwise specified, the terms and expressions used below have the meanings commonly understood by those skilled in the art.

[0026] Unless otherwise stated, "%" in this invention refers to "mass %".

[0027] To address the issue of easy nozzle blockage during continuous casting of low-silicon steel due to aluminum reduction for silicon increase, a new low-silicon steel smelting method has been developed. This method avoids silicon increase during smelting, which could lead to excessive silicon content, while simultaneously enabling continuous casting.

[0028] Currently, in the production of low-silicon steel, the use of aluminum reduction can cause excessive silicon content in molten steel and easy blockage of the nozzle during continuous casting. In response to these problems, the inventors of this invention have conducted in-depth research on the smelting process and process parameters, and thus proposed a low-silicon steel smelting method, the process route of which is: hot metal pretreatment → converter → LF refining → continuous casting.

[0029] The basic concept of the low-silicon steel smelting method of the present invention is:

[0030] 1. Reduce the SiO2 content in the slag to prevent excessive Si content caused by aluminum reduction of SiO2 during refining;

[0031] 2. Carbon is used for deoxidation in smelting to reduce the amount of Al2O3 inclusions; carbon particles are used for pre-deoxidation in converter tapping to reduce the amount of aluminum deoxidizer used; carbon powder diffusion deoxidation is used in LF to reduce the amount of Al2O3 generated during refining and avoid blockage of the downstream nozzle.

[0032] 3. The converter adopts a one-time aluminum addition method to generate Al2O3 inclusions in advance. No aluminum is added later to avoid the formation of new Al2O3 inclusions and extend the floating and removal time of Al2O3 inclusions.

[0033] Based on the above design concept, the low-silicon steel smelting method of the present invention specifically includes the following steps:

[0034] (1) Converter smelting.

[0035] After pretreatment, the molten iron is charged into the converter for smelting. The pretreatment method for molten iron can adopt relevant solutions in the existing technology, which will not be elaborated here.

[0036] In this invention, the converter smelting process adopts a dual-slag operation. After the desiliconization is completed in the early stage of the converter, a portion of the desiliconized slag is discarded, with the amount of slag discarded being 40% to 60%. New slag is then generated for decarburization, and the basicity of the converter slag is controlled at 3.5 to 4.5.

[0037] In this invention, the desiliconization process in the early stage of the converter is completed, which means that the reaction Si + O2 = SiO2 is completed. Therefore, the completion of desiliconization in the converter can be determined by the oxygen blowing rate: oxygen blowing rate = molten iron quantity × molten iron silicon content ÷ 28 × 32 ÷ oxygen utilization rate.

[0038] In this invention, after the converter desiliconization is completed, 40% to 60% of the slag is dumped, which not only reduces the amount of SiO2, but also reduces the amount of lime added, increases the slag basicity, and is beneficial to improving dephosphorization efficiency and protecting the furnace lining.

[0039] Based on the inventor's research, after the converter desiliconization process ends, it enters the decarburization period. Due to the large amount of SiO2 produced during desiliconization, the slag basicity (CaO / SiO2) is relatively low, generally around 1.2. To ensure the purpose of converter dephosphorization and protect the furnace lining, lime needs to be added again during the decarburization period to rebuild the slag and increase the slag basicity to around 3.0. The specific operation of rebuilding new slag for decarburization is a conventional operation. This invention adopts a double-slag method of discarding the desiliconized slag and then rebuilding the slag, which can quickly increase the slag basicity to 3.5-4.5, thereby improving the converter dephosphorization rate.

[0040] This invention achieves a rapid increase in slag basicity to 3.5–4.5 by reducing the total SiO2 content in the slag and adding a small amount of lime.

[0041] In this invention, the oxidizing properties at the endpoint of converter smelting are controlled using a high-flow-rate bottom-blowing process. Before tapping, [C]·[O] is controlled to be ≤0.0016, and bottom-blowing CO2 stirring is performed for 1.5–2.5 min before tapping, with a bottom-blowing gas supply intensity of 0.15–0.20 Nm. 3 / (min·t) (that is, 0.15~0.20 Nm per minute per ton of molten steel) 3 ), preferably 0.20 Nm 3 / (min﹒t), the converter tapping adopts slag-blocking cone + sliding plate slag blocking, and the slag amount and slag thickness are <30mm.

[0042] Among them, [C]·[O] is called the carbon-oxygen product, which is the product of the C content and O content in the molten steel. In steelmaking, the carbon-oxygen product is generally used to represent the oxidizing power of steel. A high carbon-oxygen product indicates strong oxidizing power, which requires a larger amount of deoxidizer and produces more inclusions, which is detrimental to smelting. Under normal conditions, the [C]·[O] in a converter is between 0.0018 and 0.0023. Controlling the carbon-oxygen product to a lower level (≤0.0016) can reduce the amount of aluminum added as a deoxidizer.

[0043] Bottom-blown inert gases (N2, Ar, CO2) can achieve converter stirring, accelerate the flow of molten steel, promote the rapid decarburization reaction and uniform temperature, reduce the oxygen content in the steel, and lower the [C]·[O] of the molten steel. In this invention, CO2 is used as the bottom-blown gas.

[0044] In short, this step uses a double-slag operation in the converter to create high-basicity slag, reducing the SiO2 content in the converter slag. The double-slag-blocking operation at the converter tapping reduces the amount of slag discharged from the converter, thus avoiding excessive Si content caused by aluminum reduction of SiO2 during the LF refining process.

[0045] (2) Steel tapping from the converter.

[0046] In this invention, carbon powder is used for pre-deoxidation during converter tapping. Carbon powder is added to the ladle at a rate of 0.2–0.3 kg / t (i.e., 0.2–0.3 kg of carbon powder per ton of molten steel). When two-thirds of the steel has been tapped, manganese alloy and aluminum shot are added for deep deoxidation. All aluminum is added during converter tapping. Lime is added at a rate of 5–6 kg / t (i.e., 5–6 kg of lime per ton of molten steel). The impact of the tapping steel flow rapidly forms slag. After tapping, the steel is bottom-blown for 2–3 minutes.

[0047] In this invention, the amount of manganese alloy added is determined according to the Mn content of the steel grade. The amount of manganese alloy added = steel content × Mn content ÷ manganese alloy content ÷ manganese alloy yield. The amount of aluminum shot added is generally controlled within 500 kg / furnace, that is, within 2.8 kg / t steel.

[0048] Bottom-blown gas supply intensity of converter ≥ 0.10 Nm 3 / (min·t) can be referred to as high-flow-rate bottom blowing. The bottom blowing gas can be Ar or CO2; this invention uses CO2. Based on the inventor's research, high-flow-rate bottom blowing in converters can reduce the carbon-oxygen product in steel and decrease the oxidizability of molten steel.

[0049] In short, the converter tapping process uses carbon particle pre-deoxidation, producing CO2 gas, which does not contaminate the molten steel. This is beneficial for slag foaming and slag-steel reaction, and it reduces the amount of aluminum added, thereby reducing Al2O3 production. Furthermore, the one-time aluminum addition at the converter tapping stage allows for earlier Al2O3 formation and flotation, increasing the time for inclusion removal. By reducing Al2O3 production and enabling its earlier formation and flotation, the likelihood of nozzle blockage can be reduced.

[0050] (3) LF refining.

[0051] In this invention, after the molten steel enters the LF furnace, carbon powder diffusion deoxidation is applied to the slag surface, with a carbon powder amount of 15-30 kg / furnace. The LF furnace produces high-basicity refining slag, the composition of which is: (FeO+MnO)≤1.0%, CaO 50%-60%, SiO2 8%-12%, Al2O3 20%-30%, MgO 6%-8%. By producing high-basicity refining slag, the amount of silicon added during the smelting process can be reduced.

[0052] When the converter taps steel, slag is added. The basicity of the converter slag is 3.5. At the same time, the silicon contained in the alloy oxidizes to generate SiO2, which causes the basicity of the initial LF slag to be ≤3.5. It is necessary to add lime to the converter tapping or LF entering the station to make slag, so as to increase the basicity of the slag (CaO / SiO2) to 5-10, which is to make high basicity refining slag for LF.

[0053] The oxidizing power of slag is generally indicated by the (FeO+MnO) content. The lower the (FeO+MnO) content, the weaker the oxidizing power of the slag, and the better the deoxidation and desulfurization effect. LF slag surface uses carbon powder, which can react with the (FeO+MnO) in the slag: FeO+C=Fe+CO↑, MnO+C=Mn+CO↑. The generated CO gas escapes from the molten steel, reducing the (FeO+MnO) content in the slag and increasing its basicity, thus achieving highly efficient deoxidation and desulfurization.

[0054] In this invention, the bottom-blown CO2 gas stirring in the LF refining process adopts medium stirring, with a bottom-blowing intensity of 200-400 L / min. Large stirring is not performed during the process to prevent secondary oxidation of aluminum caused by exposed molten steel. Soft stirring is performed before tapping, with a soft stirring time of >10 min. The steel is tapped after the temperature and composition are suitable.

[0055] Soft stirring refers to a slight ripple on the surface of the molten steel, without exposing the surface. Soft stirring promotes the removal of inclusions in the steel, improving the purity of the molten steel. The longer the soft stirring time, the higher the inclusion removal rate and the purer the steel quality. If the stirring intensity is high, the surface of the molten steel will be exposed, and O2 in the air will react with Al in the steel to form Al2O3 inclusions, which will contaminate the molten steel and reduce its purity.

[0056] In short, similar to the effect of carbon pre-deoxidation in converter steelmaking, LF refining uses carbon powder deoxidation, producing CO2 gas as the product, which does not contaminate the molten steel and is beneficial for slag foaming and slag-steel reaction. Furthermore, controlling the stirring intensity and avoiding excessive stirring during LF refining can prevent secondary oxidation of aluminum.

[0057] The molten steel output from the LF furnace is hoisted to the continuous casting process for continuous casting. For details, please refer to the relevant solutions in the existing technology, which will not be elaborated here.

[0058] The low-silicon steel smelting method of the present invention is applicable to the production of any type of low-silicon steel, such as low-silicon steels Q195LD, SPHC, S275JR-1, S355JR-1, etc., which require Si≤0.03%.

[0059] The low-silicon steel smelting method of the present invention can control the Si content in LF refined steel to a level of Si≤0.02%, for example, the silicon content is 0.005%-0.020%.

[0060] Example

[0061] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments, unless otherwise specified, are performed according to conventional methods and conditions.

[0062] Example 1: Production of Q195LD low-silicon steel using a 180-ton converter

[0063] This embodiment uses a 180-ton converter to smelt Q195LD low-silicon steel (the main components of Q195LD steel are: C≤0.06%, Si≤0.03%, Mn 0.25~0.50%, P≤0.025%, S≤0.020%, Al 0.02~0.07%). The process route is: hot metal pretreatment → converter → LF refining → continuous casting.

[0064] The process in this embodiment is as follows:

[0065] (1) The converter smelting process adopts a dual-slag operation. After the desiliconization is completed in the early stage of the converter, a portion of the desiliconized slag is discarded, with a slag discarding rate of 50%. New slag is then generated for decarburization, and the basicity of the converter slag is controlled at 4.2. The oxidizing power at the endpoint of converter smelting is controlled by a high-flow-rate bottom blowing process. Before tapping, [C]·[O] is controlled to be ≤0.0016. Before tapping, bottom blowing CO2 is used for stirring for 2.0 min, and the bottom blowing gas supply intensity is 0.20 Nm. 3 / (min﹒t), the converter tapping adopts slag-blocking cone + sliding plate slag blocking, and the slag amount and slag thickness are <30mm.

[0066] (2) Carbon particles are used for pre-deoxidation when the converter taps steel. 40 kg of carbon powder is added to the ladle. When 2 / 3 of the steel is tapped, 820 kg of medium manganese alloy and 500 kg of aluminum shot are added. 1000 kg of lime is added. The steel flow impacts the steel to quickly form slag. After the steel is tapped, the bottom is blown and stirred for 3 minutes at a high flow rate.

[0067] (3) After the molten steel enters the LF furnace, carbon powder diffusion deoxidation is applied to the slag surface at a rate of 30 kg / furnace. The LF furnace produces a high-basicity refining slag with the following composition: CaO: 53%, SiO2: 9%, Al2O3: 28%, MgO: 7.5%. The bottom blowing stirring during the LF refining process uses medium stirring at a rate of 300 L / min. Large stirring is not performed during the process to prevent secondary oxidation of aluminum caused by exposed molten steel. Soft stirring is performed before tapping the steel for 12 minutes. The steel is tapped after the temperature and composition are suitable. The steel composition is: C: 0.034%, Si: 0.015%, Mn: 0.35%, P: 0.015%, S: 0.010%, Al: 0.045%.

[0068] Molten steel is hoisted to the continuous casting process for continuous casting.

[0069] Example 2: Production of S355JR-1 low silicon steel using a 180-ton converter

[0070] This embodiment uses a 180-ton converter to smelt S355JR-1 low-silicon steel (the main components of S355JR-1 steel are: C≤0.06%, Si≤0.03%, Mn:1.20~1.40%, P≤0.020%, S≤0.015%, Al:0.015~0.06%, Cr:0.3~0.35%, Nb:0.017~0.027%). The process route is: hot metal pretreatment → converter → LF refining → continuous casting.

[0071] The process in this embodiment is as follows:

[0072] (1) The converter smelting process adopts a dual-slag operation. After the desiliconization is completed in the early stage of the converter, a portion of the desiliconized slag is discarded, with a slag discarding rate of 50%. New slag is then generated for decarburization, and the basicity of the converter slag is controlled at 4.2. The oxidizing power at the endpoint of converter smelting is controlled by a high-flow-rate bottom blowing process. Before tapping, [C]·[O] is controlled to be ≤0.0016. Before tapping, bottom blowing CO2 is used for stirring for 2.0 min, and the bottom blowing gas supply intensity is 0.20 Nm. 3 / (min﹒t), the converter tapping adopts slag-blocking cone + sliding plate slag blocking, and the slag amount and slag thickness are <30mm.

[0073] (2) Carbon particles are used for pre-deoxidation when the converter taps steel. 50 kg of carbon powder is added to the ladle. When 2 / 3 of the steel is tapped, 2900 kg of medium manganese alloy and 500 kg of aluminum shot are added. 1000 kg of lime is added. The steel flow impacts the steel to quickly form slag. After the steel is tapped, the bottom is blown and stirred for 3 minutes at a high flow rate.

[0074] (3) After the molten steel enters the LF furnace, carbon powder diffusion deoxidation is applied to the slag surface at a rate of 30 kg / furnace. The LF furnace produces a high-basicity refining slag with the following composition: CaO: 55%, SiO2: 10%, Al2O3: 26%, MgO: 7%. The bottom blowing stirring during the LF refining process uses medium stirring at a rate of 320 L / min. Large stirring is not performed during the process to prevent secondary oxidation of aluminum caused by exposed molten steel. Soft stirring is performed before tapping the steel for 12 minutes. The steel is tapped after the temperature and composition are suitable. The steel composition is: C: 0.03%, Si: 0.018%, Mn: 1.25%, P: 0.015%, S: 0.010%, Al: 0.040%.

[0075] Molten steel is hoisted to the continuous casting process for continuous casting.

[0076] Comparative Example 1: Production of Q195LD low silicon steel using a 180-ton converter

[0077] This comparative example uses a 180-ton converter to smelt Q195LD low-silicon steel (the main components of Q195LD steel are: C≤0.06%, Si≤0.03%, Mn:0.25~0.50%, P≤0.025%, S≤0.020%, Al:0.02~0.07%). The process route is: hot metal pretreatment → converter → LF refining → continuous casting.

[0078] The comparison process is as follows:

[0079] (1) The converter smelting adopts the single slag method and controls the converter slag basicity to 3.2. The converter adopts the high flow bottom blowing process. Before tapping, [C] and [O] are 0.0020. The converter tapping adopts the sliding plate slag blocking method and the slag amount and thickness are <50mm.

[0080] (2) Aluminum deoxidation is used for steel tapping in the converter. 820 kg of medium manganese alloy and 450 kg of aluminum shot are added during steel tapping in the converter. 1000 kg of lime is added. The steel flow impacts the slag to form slag quickly. After steel tapping is completed, the bottom is blown and stirred for 3 minutes at a high flow rate.

[0081] (3) After the molten steel enters the LF (Left-Stage Furnace), 500 kg of lime is added, and the slag is stirred at a high flow rate. During the LF smelting process, 150 kg of aluminum shot is added. The composition of the LF refining slag is CaO: 50%, SiO2: 4.5%, Al2O3: 34%, MgO: 8%. Soft stirring is performed before tapping the steel, and the molten steel is soft stirred for 12 minutes. The steel is tapped after the temperature and composition are suitable. The steel composition is: C: 0.034%, Si: 0.038%, Mn: 0.35%, P: 0.015%, S: 0.010%, Al: 0.045%.

[0082] Molten steel is hoisted to the continuous casting process for continuous casting.

[0083] The comparison results of the examples and comparative examples are shown in the table below:

[0084]

[0085] As can be seen from the examples and comparative examples, the silicon content of the finished product using the present invention can be controlled at Si≤0.02%. With the same aluminum content, aluminum consumption is reduced, saving 0.55 kg / t of aluminum consumption and 2.77 kg / t of lime consumption, thereby reducing costs and improving the quality of steel.

[0086] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any substitutions, modifications, combinations, changes, simplifications, etc., made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for smelting low-silicon steel, characterized in that, Includes the following steps: (1) The pretreated molten iron is charged into the converter. The smelting process adopts a double slag operation. After desiliconization, a portion of the desiliconized slag is discarded, and new slag is generated for decarburization. The basicity of the converter slag is controlled at 3.5~4.

5. Before tapping the steel after the converter smelting is completed, [C]·[O]≤0.0016 is controlled, and the basicity is 0.15~0.20 Nm. 3 Bottom-blown CO2 with a gas supply intensity of / (min·t) and stirring for 1.5~2.5 min; (2) When tapping steel from the converter, add carbon powder to the ladle at a rate of 0.2~0.3 kg / t for pre-deoxidation. When 2 / 3 of the steel is tapped, add manganese alloy and aluminum shot to the ladle for deep deoxidation, and ensure that all aluminum shot is added when tapping steel from the converter. (3) When molten steel enters the LF furnace, carbon powder diffusion deoxidation is used on the slag surface, and high-basicity refining slag is generated during the refining process; The amount of carbon powder used is 15~30kg / furnace, and the composition of the high-alkalinity refining slag is: CaO 50%~60%, SiO2 8%~12%, Al2O3 20%~30%, MgO 6%~8%.

2. The method for smelting low-silicon steel according to claim 1, characterized in that, In step (1), the amount of slag removed after desilication is 40%~60%.

3. The method for smelting low-silicon steel according to claim 1, characterized in that, In step (2), the converter tapping process adopts a double slag-blocking operation using a slag-blocking cone and a sliding plate to control the slag amount so that the slag thickness is <30mm.

4. The method for smelting low-silicon steel according to claim 1, characterized in that, In step (2), when the converter taps steel, lime is added at a rate of 5-6 kg / t to form slag by impacting the steel flow; after the converter taps steel, the bottom is blown and stirred at a high flow rate for 2-3 minutes.

5. The method for smelting low-silicon steel according to claim 1, characterized in that, In step (3), the bottom blowing intensity used for bottom blowing agitation in the refining process is 200~400L / min.

6. The method for smelting low-silicon steel according to claim 1, characterized in that, In step (3), soft stirring is performed before tapping the steel, with a bottom blowing intensity of 50~100L / min and a soft stirring time of >10min.

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