A green high-clean low-cost low-carbon steel composite deoxidation production method

Abstract

The application discloses a green high-clean low-cost low-carbon steel composite deoxidization production method and belongs to the technical field of steel metallurgy and steelmaking process technology. The method adopts an integrated new process of converter tapping trace carbon particle weak pre-deoxidization, RH deep vacuum hydrogen circulation final deoxidization and RH deep vacuum argon rapid dehydrogenation; the carbon particle pre-deoxidization realizes only deoxidization, no carbon increment and no inclusion; hydrogen reacts with oxygen under deep vacuum to generate gaseous water, thereby thoroughly eliminating Al2O3 inclusions; deoxidization and dehydrogenation are completed in the same cycle of the RH process, low oxygen, low hydrogen and high cleanliness are realized; through synergistic carbon control, the finished product carbon is guaranteed to be less than or equal to 0.06%; and the hydrogen safety interlocking control is matched, thereby realizing industrialized stable application. The application solves the technical problems of traditional aluminum deoxidization of low-carbon steel, such as many inclusions, nozzle clogging, low cleanliness and high carbon emission, and has remarkable creativity and industrial application value.

Description

Technical Field

[0001] This invention belongs to the field of steelmaking process technology in iron and steel metallurgy, and particularly relates to a green, high-cleanliness, low-cost, and composite deoxidation production method for low-carbon steel. It employs a green, low-carbon, and high-cleanliness steelmaking method that combines pre-deoxidation of carbon particles from converter tapping with final deoxidation using RH deep vacuum circulating hydrogen gas. Background Technology

[0002] Low-carbon steels possess excellent deep-drawing performance, weldability, and surface quality, and are widely used in home appliances, automobiles, and high-end equipment. These steels require extremely high cleanliness, with strict control over total oxygen content. In particular, oxide inclusions, primarily Al2O3, are high-hardness and brittle inclusions that easily aggregate in molten steel and are difficult to remove. These inclusions directly affect surface quality and stamping performance, reduce fatigue life, impact toughness, tensile / yield strength, increase the risk of brittle fracture, disrupt matrix continuity, and reduce corrosion resistance and wear resistance. Currently, industrial production mainly employs a "converter smelting + RH refining + aluminum deoxidation" process, which has the following technical defects:

[0003] Aluminum deoxidation generates a large amount of Al2O3 inclusions, which are difficult to float completely, easily causing nozzle clogging, continuous casting problems, product surface defects, and excessive internal inclusions.

[0004] The molten steel has a high oxygen content, a large deoxidation load, high alloy consumption, and high carbon emissions;

[0005] The RH argon circulation dynamics are weak, resulting in limited efficiency in deoxygenation and inclusion removal.

[0006] The production process involves the extensive use of alloys such as aluminum, silicon, and manganese, resulting in high resource consumption and carbon emissions.

[0007] Hydrogen deoxidation produces H2O gas, which can be completely eliminated under vacuum conditions without generating any solid inclusions, making it an ideal method for achieving high-purity smelting. However, currently, there is a lack of a complete hydrogen deoxidation process suitable for large converters, with precise control of the finished product carbon content (≤0.06%), ensuring safety and controllability, and suitable for industrial application. Therefore, this invention provides a method for smelting low-carbon, high-purity steel using converter carbon particle pre-deoxidation and RH circulating hydrogen final deoxidation to solve the problems of existing technologies.

[0008] Patent search revealed that CN106244761B discloses a method for preparing high-purity IF steel. This patent describes a process involving the batch addition of carbon powder for deoxidation during deep vacuum treatment in the RH process. Compared to the normal process, this reduces the amount of aluminum-iron deoxidizer added, lowers oxide inclusions in the steel, and ultimately improves the cleanliness control level of the molten steel. In contrast, this invention employs a two-step deoxidation method. The first step involves uniformly adding a certain amount of carbon powder to the molten steel during the converter tapping process for pre-deoxidation. The second step utilizes hydrogen circulation under deep vacuum conditions in the RH process to achieve final deoxidation. During the RH hydrogen deoxidation process, a system interlock control is implemented to ensure that the oxygen content in the vacuum tank is <0.5%. The hydrogen interlock system has explosion-proof, anti-static, emergency shut-off, and leak detection functions to ensure production safety. Using this invention's process significantly reduces oxide inclusions in the molten steel, ultimately meeting the required cleanliness control. This process is unique and possesses strong novelty and originality.

[0009] Patent search revealed that CN118910489B discloses a "High-Cleanliness IF Steel Production Process." This patent utilizes a deep vacuum (VD) system, switching to hydrogen via a bottom-blowing system in the ladle, and then reacting hydrogen with oxygen in the steel under deep vacuum conditions to remove free oxygen, significantly reducing oxide inclusions and improving steel cleanliness. In contrast, this invention employs a two-step deoxidation process. The first step involves uniformly adding a certain amount of carbon powder to the molten steel during the converter tapping process for pre-deoxidation. The second step involves a final deoxidation process using hydrogen circulation under deep vacuum conditions during the RH process. The RH hydrogen deoxidation process employs system interlocking control, ensuring the oxygen content in the vacuum tank is <0.5%. The hydrogen interlocking system features explosion-proof, anti-static, emergency shut-off, and leak detection functions to guarantee production safety. Although both the RH process circulating hydrogen deoxidation and the retrieved patent use hydrogen for deoxidation and share the same deoxidation principle, the two processes differ significantly in terms of operation and control, representing two completely different deoxidation operations. This invention possesses a certain degree of innovation in both aspects. After treatment using the process of this invention, the oxide inclusions in the molten steel are significantly reduced, ultimately meeting the requirements for steel cleanliness control.

[0010] Patent search revealed that CN119082402A, entitled "A Method for Reducing Inclusions in IF Steel and Improving Steel Cleanliness," primarily involves adding carbon particles after manganese alloying in the RH process to replace part of the aluminum-iron deoxidation, thereby reducing inclusions, mainly Al2O3 oxides, and improving steel cleanliness control. However, this process still uses aluminum-iron deoxidation for final deoxidation, offering only a slight improvement over traditional deoxidation processes. In contrast, this invention employs a two-step deoxidation method. The first step involves uniformly adding a certain amount of carbon powder to the molten steel during the converter tapping process for pre-deoxidation. The second step utilizes hydrogen circulation under deep vacuum conditions in the RH process to achieve final deoxidation. During the RH hydrogen deoxidation process, a system interlock control is implemented, ensuring the oxygen content in the vacuum tank is <0.5%. The hydrogen interlock system features explosion-proof, anti-static, emergency shut-off, and leak detection functions to ensure production safety. This patented aluminum-iron alloy is consumed primarily, significantly reducing the inclusion of Al2O3, the main oxide, in steel, ultimately meeting the requirements for steel cleanliness control. At the same time, it greatly improves the turbulence phenomenon at the sprue during the casting process, enhances the pourability of molten steel, and reduces the risk and cost of replacing invasive sprues.

[0011] All three patents mentioned above relate to methods for improving the cleanliness control of IF steel. They share several commonalities: Patents 1 and 3 employ an RH process for carbon particle deoxidation, while this patent uses a converter process for pre-deoxidation; Patent 3 and this invention both use hydrogen deoxidation, but the two processes are completely different in terms of operation and control, requiring entirely different equipment and exhibiting significant differences. However, from the perspective of cleanliness control, all three processes offer certain optimizations and improvements compared to traditional methods. Summary of the Invention

[0012] The purpose of this invention is to provide a green, high-cleanliness, low-cost, and composite deoxidation method for low-carbon steel. This method employs a two-step converter steelmaking process combining pre-deoxidation of carbon particles at the tapping stage with final deoxidation using RH deep vacuum circulating hydrogen gas. Safety measures include a system interlocking control during the RH hydrogen deoxidation process, ensuring the oxygen content in the vacuum tank is <0.5%. The hydrogen interlocking system features explosion-proof, anti-static, emergency shut-off, and leak detection functions to guarantee production process safety.

[0013] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0014] This invention discloses a green, high-cleanliness, low-cost, low-carbon steel composite deoxidation production method, comprising:

[0015] 1) Composition design: The composition of the low carbon steel by mass percentage is C: ≤0.06%, Si: ≤0.03%, Mn: ≤0.40%, P: ≤0.025%, S: ≤0.015%, Al: 0.015-0.055%, N: ≤0.0040%, O: ≤0.0010%, with the remainder being Fe and unavoidable impurities;

[0016] 2) Iron pretreatment: Desulfurize the molten iron to ensure that the [S] content is ≤0.003%;

[0017] 3) Top and bottom blowing converter smelting: control the tapping temperature at 1670~1700℃, and the oxygen content in the tapping steel ≤800ppm;

[0018] 4) Pre-deoxidation of carbon particles during tapping: Carbon particles are added evenly with the steel stream during the tapping process, at a rate of 0.2-0.6 kg / t. If the steel is severely over-oxidized, the amount of carbon particles added can be appropriately increased to perform pre-deoxidation of the steel, reducing the oxygen content of the steel to 250-450 ppm. After tapping, 0.3-0.7 tons / heat of modifier is added using a distributor to ensure that the modifier is evenly covered on the surface of the top slag.

[0019] 5) RH deep vacuum hydrogen final deoxidation: The molten steel is sent into the RH vacuum refining station and evacuated to a vacuum degree ≤60Pa. Argon gas is introduced through the riser pipe for 5 minutes. Then, pure hydrogen is switched as the circulating gas with a hydrogen flow rate of 800~2000NL / min and a processing time of 8~15 minutes to complete the final deoxidation.

[0020] 6) Dehydrogenation and homogenization treatment: After hydrogen deoxygenation is completed, switch to argon circulation with an argon flow rate of 600-1200 NL / min and a treatment time of 5-10 min to make the hydrogen content of the molten steel ≤1.5ppm;

[0021] 7) Precise carbon control and continuous casting: Through the coordinated regulation of converter endpoint control and RH light treatment, the chemical composition of the casting machine meets the requirements of 1); the casting machine adopts full-process protection casting to obtain low-carbon and high-cleanliness steel billets.

[0022] Furthermore, the carbonaceous deoxidizer is low-sulfur, low-nitrogen graphite carbon particles or calcined coke, with a carbon content ≥95% and a particle size of 3–12 mm.

[0023] Furthermore, during the H-hydrogen deoxygenation process, the system oxygen content is interlocked and controlled to be <0.5%.

[0024] Furthermore, the hydrogen system used in the H-hydrogen deoxygenation process has explosion-proof, anti-static, emergency shut-off, and leak detection functions.

[0025] Furthermore, after the RH treatment vacuum process, there is no need for the traditional Al2O3 inclusion modified calcium treatment process, and there is no flocculation phenomenon during the casting process.

[0026] Furthermore, after treatment by this method, the total oxygen content of the molten steel is T[O]≤10ppm, [H]≤1.5ppm, and there are no brittle Al2O3 inclusions.

[0027] Furthermore, for hot-rolled coils, the inclusion control is grade 0 for all categories except for the D-type fine series (0.5 grade); this applies to low-carbon steel, ultra-low-carbon steel, IF steel, cold-rolled outer plate steel, and low-alloy high-strength steel with a carbon content ≤0.06%.

[0028] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0029] A unique two-step deoxidation system ensures that the steel is virtually free of Al2O3-based oxygen inclusions after purification treatment, resulting in extremely clean low-carbon steel with a precise control of ≤0.06%. An innovative integrated hydrogen deoxidation and argon dehydrogenation process using RH vacuum avoids hydrogen embrittlement. Employing strong circulation dynamics, deoxidation efficiency is increased by over 50%. The system innovatively eliminates the calcium treatment process for inclusion modification, improving cleanliness while reducing alloy consumption. It also eliminates Al2O3-type inclusions and nozzle nodules, ensuring smooth continuous casting and reducing alloy consumption. A comprehensive low-carbon emission reduction and safety interlock system makes it suitable for large-scale industrial production in converters. Detailed Implementation

[0030] The composition of the low-carbon steel of this invention, by mass percentage, is C: ≤0.06%, Si: ≤0.03%, Mn: ≤0.40%, P: ≤0.025%, S: ≤0.015%, Al: 0.015-0.055%, N: ≤0.0040%, O: ≤0.0010%, with the remainder being Fe and unavoidable impurities;

[0031] Furthermore, its chemical composition by weight percentage is C: 0.015%, Si: 0.03%, Mn: 0.16%, P: 0.012%, S: 0.005%, Alt: 0.031%, N: 0.0026%, O: 0.0009%, with the balance being Fe and unavoidable impurities.

[0032] Furthermore, its chemical composition by weight percentage is C: 0.032%, Si: 0.03%, Mn: 0.23%, P: 0.014%, S: 0.003%, Alt: 0.027%, N: 0.0031%, O: ≤0.0009%, with the balance being Fe and unavoidable impurities.

[0033] Process route: KR desulfurization → converter smelting → RH vacuum → (LF refining and heating selected according to temperature conditions) → slab continuous casting;

[0034] The key process points are as follows:

[0035] Step 1: Hot metal pretreatment. The hot metal is desulfurized. The KR hot metal desulfurization process adopts deep desulfurization technology, with a stirring time of ≥15min. After stirring, the metal is allowed to stand and then the first slag removal is performed, with a slag removal rate of ≥95%. After the first slag removal, the metal is allowed to stand for ≥3min and then the second slag removal is performed, with a slag removal rate of ≥95%. After the slag removal is completed, a sample is taken for temperature measurement. The sulfur content of the KR hot metal leaving the station is less than 0.001%, thus obtaining deep desulfurized hot metal.

[0036] Step 2: Smelting in a top-and-bottom blown converter, controlling the tapping temperature at 1670-1700℃, with [P] ≤ 0.010% and oxygen content ≤ 800ppm;

[0037] Step 3: Carbon pre-deoxidation is performed during the tapping process. Carbon particles are added evenly with the steel stream during tapping, at a rate of 0.2–0.6 kg / t. For steel with severe over-oxidation, the amount of carbon particles added can be appropriately increased to pre-deoxidize the steel and reduce the oxygen content of the steel to 250–450 ppm. During the tapping process, 0.5–1.5 tons / heat of top slag quicklime is added. When adding the top slag quicklime, avoid rapid and concentrated addition that may cause clumping. It should be evenly covered on the surface of the molten steel, which can provide a certain heat preservation effect. After tapping, a backstop operation is used to minimize slag discharge. Argon gas stirring is prohibited in the ladle throughout the tapping process. After tapping, 0.1–0.5 tons / heat of modifier is added using a distributor to evenly cover the surface of the top slag.

[0038] Step 4: RH deep vacuum hydrogen final deoxidation. The molten steel is sent to the RH vacuum refining station and evacuated to a vacuum degree ≤60Pa. Argon gas is circulated through the riser for 5 minutes, and then pure hydrogen is switched as the circulating gas. The hydrogen flow rate is 800-2000 NL / min, and the processing time is 8-15 minutes to complete the final deoxidation. During the RH hydrogen deoxidation process, the oxygen content of the system is interlocked and controlled to be <0.5%, ensuring that the hydrogen detection system has explosion-proof, anti-static, emergency shut-off, and leak detection functions.

[0039] Step 5: Dehydrogenation and homogenization treatment. After hydrogen deoxidation, switch to argon circulation with an argon flow rate of 600–1200 NL / min and a treatment time of 5–10 min to ensure the hydrogen content of the molten steel is ≤1.5 ppm, and to complete compositional alloying and homogenization. After RH vacuum treatment, perform secondary modification treatment by uniformly adding 200–300 kg / furnace of modifier to the surface of the top slag.

[0040] Step 6: Continuous casting utilizes converter endpoint control and RH light treatment in synergistic regulation to ensure the chemical composition of the casting meets the finished product requirements. Before pouring, the tundish is purged with argon gas. During pouring, argon gas is continuously purged into the tundish while a covering agent is added. After pouring, slag detection equipment is used to prevent slag from entering the ladle. The tundish superheat is controlled within the range of 15–35℃ during pouring, and the production speed is 1.3–1.4 m / min. The casting machine employs full-process protective pouring to obtain low-carbon, high-cleanliness steel billets.

[0041] Furthermore, after treatment by this method, the total oxygen content of the molten steel is T[O]≤10ppm, [H]≤1.5ppm, and there are basically no Al2O3 brittle inclusions. After adopting the method of this invention, the inclusion control level is stably achieved throughout the year, reaching Class A, Class C, and DS Class 0 control, and Class B and D Class less than 0.5 control level. The inclusion control reaches the industry-leading level, and the surface quality defects of the test coil are significantly lower, achieving stable control of high cleanliness of low carbon steel.

[0042] The present invention will be described in more detail below with reference to examples. These examples are merely descriptions of the best mode of implementation of the invention and do not limit the scope of the invention in any way.

[0043] Example 1

[0044] Hot metal pretreatment involves desulfurization of the molten iron, ensuring the sulfur content in the KR-delivered hot metal is less than 0.001%, resulting in deeply desulfurized hot metal. The molten iron is then smelted in a top-and-bottom blown converter, with the tapping temperature controlled at 1676℃, [P] ≤ 0.008%, and the oxygen content at tapping 620ppm. During tapping, carbon particles are added uniformly with the steel stream at a rate of 150kg for pre-deoxidation, resulting in a final oxygen content of 400ppm in the ladle. Finally, 0.9 tons of top slag quicklime are added during tapping, and the quicklime is then used after tapping. During the entire tapping process, argon gas stirring in the ladle is prohibited. After tapping, 0.3 tons of modifier are added using a material distributor to evenly cover the top slag surface. The molten steel is then sent to the RH vacuum refining station, where it is evacuated to a vacuum degree of 50 Pa. Argon gas is then introduced through the riser for 5 minutes, followed by switching to pure hydrogen as the circulating gas at a flow rate of 1000 NL / min for 10 minutes. This completes the final deoxidation, with the online oxygen determination [O] at 8 ppm. The online detection shows the oxygen content of the vacuum tank gas to be 0.4%. After hydrogen deoxidation, the system switches to argon gas circulation at a flow rate of 800 NL / min for 8 minutes, resulting in a hydrogen content of 0.8 ppm in the molten steel, achieving alloying and homogenization. A second modification treatment is performed after the RH vacuum treatment, with 200 kg of modifier evenly added to the top slag surface. During the casting process, the tundish superheat is controlled within a range of 25°C, and the production casting speed is 1.4 m / min. The casting machine employs full-process protective pouring to obtain low-carbon, high-cleanliness steel billets. The flow control plug operates smoothly during the pouring process, with no turbulent flow observed.

[0045] Example 2

[0046] Hot metal pretreatment involves desulfurization of the molten iron, ensuring the sulfur content in the KR-delivered hot metal is less than 0.001%, resulting in deeply desulfurized hot metal. The molten iron is then smelted in a top-and-bottom blown converter, with the tapping temperature controlled at 1685℃, [P] ≤ 0.012%, and the oxygen content at tapping 560ppm. During tapping, carbon particles are added uniformly with the steel stream at a rate of 160kg for pre-deoxidation, resulting in a final oxygen content of 350ppm in the ladle. Additionally, 0.8 tons of top slag quicklime are added during tapping, and this quicklime is then used after tapping. During the entire tapping process, argon gas stirring in the ladle is prohibited. After tapping, 0.3 tons of modifier are added using a distributor to evenly cover the top slag surface. The molten steel is then sent to the RH vacuum refining station, where it is evacuated to a vacuum degree of 50 Pa. Argon gas is then introduced through the riser for 5 minutes, followed by switching to pure hydrogen as the circulating gas at a flow rate of 1000 NL / min for 10 minutes. The final deoxidation is completed, and the online oxygen determination [O] is 9 ppm. The online detection of the oxygen content in the vacuum tank gas is 0.42%. After hydrogen deoxidation, the system switches to argon gas circulation at a flow rate of 800 NL / min for 8 minutes, resulting in a hydrogen content of 0.8 ppm in the molten steel, achieving alloying and homogenization. After the RH vacuum treatment, a second modification treatment is performed by evenly adding 180 kg of modifier to the top slag surface. During the casting process, the tundish superheat is controlled within a range of 31°C, and the production casting speed is 1.3 m / min. The casting machine employs full-process protective pouring to obtain low-carbon, high-cleanliness steel billets. The flow control plug operates smoothly during the pouring process, with no turbulent flow observed.

[0047] The chemical composition content obtained from Examples 1 and 2 is shown in Table 1, and the results of the hot-rolled coil inclusion inspection are shown in Table 2.

[0048] Table 1 Chemical Composition

[0049]

[0050] Table 2 Inclusion Inspection of Hot-Rolled Coils

[0051]

[0052] As shown in Tables 1 and 2, by employing the method of this invention, the chemical composition of the finished product and the control of inclusions in hot-rolled coils in the steelmaking and continuous casting processes both meet the target requirements. Nitrogen and oxygen contents are controlled at low levels, aluminum inclusions range from 2 to 7 ppm, and total oxygen content is controlled to less than 10 ppm, achieving high cleanliness control in the molten steel. For hot-rolled coils of different thicknesses, inclusion control is at level 0 for all categories except for category D fine inclusions (0.5 grade). Therefore, the method of this invention achieves a high level of cleanliness control for low-carbon steel grades.

[0053] The process of this invention is mature, safe and controllable, and compatible with existing production lines. It can produce high-cleanliness low-carbon steels such as IF steel, ultra-low carbon steel, low carbon steel, automotive outer panel steel, and home appliance steel on a large scale, and has significant technological progress and economic and environmental benefits.

[0054] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A green, high-cleanliness, low-cost, low-carbon steel composite deoxidation production method, characterized in that, include: 1) Composition design: The composition of the low carbon steel by mass percentage is C: ≤0.06%, Si: ≤0.03%, Mn: ≤0.40%, P: ≤0.025%, S: ≤0.015%, Al: 0.015-0.055%, N: ≤0.0040%, O: ≤0.0010%, with the remainder being Fe and unavoidable impurities; 2) Iron pretreatment: Desulfurize the molten iron to ensure that the [S] content is ≤0.003%; 3) Top and bottom blowing converter smelting: control the tapping temperature at 1670~1700℃, and the oxygen content in the tapping steel ≤800ppm; 4) Pre-deoxidation of carbon particles during tapping: Carbon particles are added evenly with the steel stream during the tapping process, at a rate of 0.2-0.6 kg / t. If the steel is severely over-oxidized, the amount of carbon particles added can be appropriately increased to perform pre-deoxidation of the steel, reducing the oxygen content of the steel to 250-450 ppm. After tapping, 0.3-0.7 tons / heat of modifier is added using a distributor to ensure that the modifier is evenly covered on the surface of the top slag. 5) RH deep vacuum hydrogen final deoxidation: The molten steel is sent into the RH vacuum refining station and evacuated to a vacuum degree ≤60Pa. Argon gas is introduced through the riser pipe for 5 minutes. Then, pure hydrogen is switched as the circulating gas with a hydrogen flow rate of 800~2000NL / min and a processing time of 8~15 minutes to complete the final deoxidation. 6) Dehydrogenation and homogenization treatment: After hydrogen deoxygenation is completed, switch to argon circulation with an argon flow rate of 600-1200 NL / min and a treatment time of 5-10 min to make the hydrogen content of the molten steel ≤1.5ppm; 7) Precise carbon control and continuous casting: Through the coordinated regulation of converter endpoint control and RH light treatment, the chemical composition of the casting machine meets the requirements of 1); the casting machine adopts full-process protection casting to obtain low-carbon and high-cleanliness steel billets.

2. The green, high-cleanliness, low-cost, low-carbon steel composite deoxidation production method according to claim 1, characterized in that, The carbonaceous deoxidizer is low-sulfur, low-nitrogen graphite carbon particles or calcined coke, with a carbon content ≥95% and a particle size of 3–12 mm.

3. The green, high-cleanliness, low-cost, low-carbon steel composite deoxidation production method according to claim 1, characterized in that, During the hydrogen deoxygenation process, the system oxygen content is interlocked and controlled to be <0.5%.

4. The green, high-cleanliness, low-cost, low-carbon steel composite deoxidation production method according to claim 1 or 3, characterized in that, The hydrogen system is equipped with explosion-proof, anti-static, emergency shut-off, and leak detection functions.

5. The green, high-cleanliness, low-cost, low-carbon steel composite deoxidation production method according to claim 1, characterized in that, After the RH treatment and vacuum treatment are completed, there is no need for the traditional Al2O3 inclusion modified calcium treatment process, and there is no flocculation phenomenon during the casting process.

6. The green, high-cleanliness, low-cost, low-carbon steel composite deoxidation production method according to claim 1 or 5, characterized in that, After treatment by this method, the total oxygen content of the molten steel is T[O]≤10ppm, [H]≤1.5ppm, and there are no Al2O3 brittle inclusions.

7. The green, high-cleanliness, low-cost, low-carbon steel composite deoxidation production method according to claim 1, characterized in that, For hot-rolled coils, inclusion control is grade 0.5 for category D fine series, and grade 0 for all other inclusion categories. This applies to low-carbon steel, ultra-low-carbon steel, IF steel, cold-rolled outer sheet steel, and low-alloy high-strength steel with a finished carbon content ≤0.06%.

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