A low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet and its preparation method

Abstract

The present invention particularly relates to a low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet and its preparation method, belonging to the technical field of steel preparation. The method comprises: subjecting molten iron to a converter to obtain converter molten steel; subjecting the converter molten steel to a tapping process to obtain tapped molten steel; refining the tapped molten steel and then continuously casting it to obtain a steel sheet; adding auxiliary materials during the tapping process, wherein the auxiliary materials include a first aluminum ash; nitrogen is added to the molten steel by replacing a nitrogen-containing alloy during converter tapping, wherein the metallic aluminum in the low-quality aluminum ash can replace some aluminum particles; and after tapping, low-quality aluminum ash is added to the slag surface of the ladle top slag to replace aluminum slag balls, thereby further reducing the oxidizability of the top slag and promoting the cleanliness of the molten steel. This method effectively recycles the low-quality aluminum ash while reducing steelmaking production costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel preparation, and in particular relates to a low-sulfur, low-oxygen, high-nitrogen tin-plated steel plate and a preparation method thereof. Background Art

[0002] With the development of high-nitrogen steel production technology, the variety and output of high-nitrogen steel are constantly increasing. Some steel grades utilize the special effects of nitrogen to improve the performance of steel. For example, high-quality tinplate utilizes the solid solution strengthening effect of nitrogen to improve the strength and hardness of tinplate. The main methods of traditional high-nitrogen steel production are alloy nitrogenization method and gas nitrogenization method. The alloy nitrogenization method mainly adds high-nitrogen alloys to the molten steel during the refining process to increase nitrogen, while using aluminum particles for deoxidation and lime for desulfurization. However, the high price of nitrogen-containing alloys and aluminum particles increases costs. The gas nitrogenization method is to blow nitrogen into the molten steel to increase the gas-liquid contact area, thereby promoting the absorption of nitrogen by the molten steel to achieve the purpose of nitrogenization. However, since the diffusion and absorption of nitrogen in the molten steel cannot be stably controlled, the nitrogenization effect is unstable. Summary of the Invention

[0003] The purpose of this application is to provide a low-sulfur, low-oxygen, high-nitrogen tin-plated steel plate and a preparation method thereof, so as to solve the problem of poor nitrogen addition effect of the current gas nitrogen addition method.

[0004] An embodiment of the present invention provides a method for preparing a low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet, the method comprising:

[0005] The molten iron is subjected to converter smelting to obtain converter molten steel;

[0006] tapping the converter molten steel to obtain tapped molten steel;

[0007] Refining the molten steel and then continuously casting it to obtain a steel plate;

[0008] Auxiliary materials are added during the steel tapping process, and the auxiliary materials include first aluminum ash.

[0009] Optionally, in the first aluminum ash, the mass content of AlN is 30%≤≤50%, and the mass content of elemental Al is 10%≤20%.

[0010] Optionally, the first aluminum ash is added when the mass of the molten steel is 1 / 10-1 / 5.

[0011] Optionally, the amount of the first aluminum ash added is W (第一铝灰) W (第一铝灰) =(N (目标) -N (初始) )*Weight of molten steel

[0012] / (S (AlN)*(41 / 14) / AlN absorption rate, where N (初始) is the initial nitrogen content of molten steel, N (目标) The lower and middle values of the target range of molten steel N content, S (AlN) is the proportion of AlN in the first aluminum ash.

[0013] Optionally, the auxiliary material further includes lime. The lime is added when the mass of the molten steel is 1 / 5-1 / 3, and the amount of lime added is 6 kg / t steel-10 kg / t steel.

[0014] Optionally, the auxiliary material further comprises aluminum particles, and the timing of adding the aluminum particles is when the mass of the molten steel is 1 / 3-1 / 2, and the amount of the aluminum particles added is W (铝粒) W (铝粒) =(([O]0-[O] (AlN) -[O] (第一铝灰) )*54 / 48+Al (目标) -Al (初始) )*weight of molten steel / alloy yield of aluminum particles, where [O]0 is the initial oxygen content of the molten steel, [O] (AlN) is the amount of oxygen consumed by the AlN reaction in the first aluminum ash, [O] (第一铝灰) is the deoxidation amount of elemental aluminum in the first aluminum ash, Al (目标) The middle value of the target Al content range of the molten steel end point, Al (初始) is the initial Al content of molten steel.

[0015] Optionally, the method further includes: adding a second aluminum ash to the surface of the ladle top slag after the steel tapping is completed, and the amount of the second aluminum ash added is 200Kg-600Kg.

[0016] Optionally, during the steel tapping process, argon is blown from the ladle at the bottom, and the flow rate of the bottom blowing argon is 600NL / min-1000NL / min.

[0017] Optionally, the chemical composition of the steel plate includes, by mass fraction: C: 0.05%-0.09%, Si: ≤0.05%, Mn: 0.3%-0.5%, P: ≤0.012%, S: ≤0.004%, Al: 0.04%-0.08%, N: 0.013%-0.025%, TO: ≤0.0025%.

[0018] Based on the same inventive concept, an embodiment of the present invention further provides a low-sulfur, low-oxygen, high-nitrogen tin-plated steel plate, which is prepared using the method for preparing the low-sulfur, low-oxygen, high-nitrogen tin-plated steel plate as described above.

[0019] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0020] The method for preparing low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet provided by the present invention utilizes AlN in aluminum ash to nitrogenize molten steel. This method fully utilizes the properties of aluminum ash with high AlN content, replacing nitrogen-enhancing alloys to effectively nitrogenize the molten steel. The small amount of elemental aluminum in the aluminum ash also partially replaces aluminum particles. Furthermore, the addition of low-quality aluminum ash in the early stages of tapping partially deoxidizes the molten steel, reducing its oxidizability. The aluminum in the aluminum ash generates deoxidation products earlier, allowing them to float and be removed, resulting in cleaner molten steel.

[0021] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a flow chart of the method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments and examples are for illustrating the present invention, rather than for limiting the present invention.

[0025] Throughout this specification, unless otherwise specified, the terms used herein should be understood as having the same meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the event of any conflict, the present specification shall take precedence.

[0026] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0027] The technical solution of the embodiment of the present application is to solve the above technical problems, and the overall idea is as follows:

[0028] During the invention process, the applicant discovered that low-quality aluminum ash, a byproduct of the aluminum industry, contains large amounts of aluminum nitride, aluminum oxide, and other impurities, resulting in a low aluminum content, difficulty in utilization, and a low price. Utilizing this low-quality aluminum ash would not only eliminate the environmental pollution caused by its accumulation but also achieve effective resource recycling. Aluminum ash has a high AlN content, and adding it to molten steel effectively increases nitrogen in the steel.

[0029] According to a typical embodiment of the present invention, a method for preparing a low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet is provided, the method comprising:

[0030] S1. The molten iron is smelted in a converter to obtain molten steel in a converter; the composition of the molten steel at the converter end is measured as the initial conditions of the molten steel for the tapping and charging operation, mainly including the initial oxygen [O]0, the initial Al (Al (初始) ), initial N(N (初始) ), initial S(S (初始) )wait.

[0031] S2. The converter molten steel is tapped to obtain molten steel; auxiliary materials are added during the tapping process, the auxiliary materials comprising a first aluminum ash;

[0032] The AlN in low-quality aluminum ash reacts with the dissolved oxygen in the molten steel as follows: 2AlN+3[O]=Al2O3+2[N]. The generated [N] disperses in the molten steel, causing the molten steel to increase in nitrogen. The amount of nitrogen increase is recorded as N (铝灰-钢) , oxygen consumption is recorded as [O] (AlN) .

[0033] In some embodiments, in the first aluminum ash, the mass content of AlN is 30%≤50%, and the mass content of elemental Al is 10%≤20%.

[0034] In some embodiments, the first aluminum ash is added when the mass of the molten steel is 1 / 10-1 / 5; the amount of the first aluminum ash added is W (第一铝灰) According to molten steel N (初始) , the middle value of the target N content range (N (目标) ), the proportion of AlN in aluminum ash (S (AlN) ) etc., specifically expressed as: W (第一铝灰) =(N (目标) -N (初始) )*molten steel weight / (S (AlN) *(41 / 14) / AlN absorption rate, where N (初始) is the initial nitrogen content of molten steel, N (目标) The lower and middle values of the target range of molten steel N content, S (AlN) is the proportion of AlN in the first aluminum ash.

[0035] Among them, the oxygen consumption of AlN in the first aluminum ash [O] (AlN) The calculation formula is as follows: [O] (AlN) =W (铝灰) *S (AlN) *60%*48 / 82 / molten steel weight*100%.

[0036] The elemental aluminum in the first aluminum ash reacts with the dissolved oxygen in the molten steel, causing the molten steel to remove some oxygen. The amount of oxygen removed from the molten steel is recorded as [O]. (铝灰) In this embodiment, the absorption amount of elemental aluminum in the first aluminum ash is 75%.

[0037] In this embodiment, the absorption rate of AlN in the first aluminum ash is 60%.

[0038] The timing of adding the first aluminum ash is controlled to be when the mass of the molten steel is 1 / 10-1 / 5; adding the first aluminum ash during this period is conducive to the full dissolution of the aluminum ash and full reaction with the molten steel.

[0039] In some embodiments, the auxiliary material further includes lime, and the lime is added when the mass of the molten steel is 1 / 5-1 / 3, and the amount of lime added is 6 kg / t steel-10 kg / t steel.

[0040] The timing of adding lime is controlled to when the mass of the molten steel is 1 / 5-1 / 3; low-quality aluminum ash has been added at the beginning of steel tapping to partially deoxidize the molten steel and reduce its oxidizability. Adding lime for desulfurization at this time will have a better effect.

[0041] In some embodiments, the auxiliary material further includes aluminum particles, and the timing of adding the aluminum particles is when the mass of the molten steel is 1 / 3-1 / 2, according to the median Al content of the target molten steel. (目标) , and the deoxidation amount of elemental aluminum in the low-quality aluminum ash added in the early stage ([O] (铝灰) ), oxygen consumption of AlN [O] (AlN) , the initial oxygen content of molten steel [O] 0, the amount of aluminum particles added W (铝粒) It can be expressed as: W (铝粒) =(([O]0-[O] (AlN) -[O] (第一铝灰) )*54 / 48+Al (目标) -Al (初始) )*weight of molten steel / alloy yield of aluminum particles, where [O]0 is the initial oxygen content of the molten steel, [O] (AlN) is the amount of oxygen consumed by the AlN reaction in the first aluminum ash, [O] (第一铝灰) is the deoxidation amount of elemental aluminum in the first aluminum ash, Al (目标) The middle value of the target Al content range of the molten steel end point, Al (初始) is the initial Al content of molten steel.

[0042] In this embodiment, the alloy yield of the aluminum particles is 78%.

[0043] The timing of adding aluminum particles should be controlled to when the mass of the molten steel is 1 / 3-1 / 2; aluminum particles should be added at least before half of the mass of the molten steel is tapped, so that there is enough time for the aluminum and molten steel to fully react, finally deoxidize the molten steel and aluminum alloy.

[0044] In this embodiment, during the steel tapping process, the ladle is subjected to bottom blowing of argon throughout the entire process to increase the circulation and stirring of the molten steel, promote the reaction and composition uniformity, and the flow rate of the bottom blowing argon is 600NL / min-1000NL / min.

[0045] In some embodiments, the method further includes: adding a second aluminum ash to the surface of the ladle top slag after the steel tapping is completed, and the amount of the second aluminum ash added is 200Kg-600Kg.

[0046] After tapping, low-quality aluminum ash is added to the ladle top slag to completely replace the aluminum slag balls. AlN and metallic Al reduce the oxidizing properties of the slag, which can further improve the cleanliness of the molten steel.

[0047] The AlN and elemental Al in the second aluminum ash react with FeO and MnO in the slag to reduce the oxidizing property of the slag and promote the cleanliness of the molten steel. At the same time, AlN reacts with FeO and MnO to generate N2, which continues to increase nitrogen in the molten steel through diffusion. The amount of nitrogen added is recorded as N (铝灰-渣) The absorption rate of AlN in the second aluminum ash in the slag is 60%. The absorption rate of nitrogen generated by AlN in the second aluminum ash by the molten steel is 30%.

[0048] S3. The molten steel is refined and then continuously cast to obtain a steel plate;

[0049] In some embodiments, the chemical composition of the steel plate includes, by mass fraction: C: 0.05%-0.09%, Si: ≤0.05%, Mn: 0.3%-0.5%, P: ≤0.012%, S: ≤0.004%, Al: 0.04%-0.08%, N: 0.013%-0.025%, TO: ≤0.0025%.

[0050] According to another typical embodiment of the present invention, a low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet is provided, and the steel sheet is prepared using the method for preparing the low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet as described above.

[0051] The low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet and its preparation method of the present application will be described in detail below with reference to examples, comparative examples and experimental data.

[0052] Example 1

[0053] A low-sulfur, low-oxygen, high-nitrogen tinplate, the specific operation steps are as follows:

[0054] (1) Measure the composition of the molten steel at the end of the converter, where the main components are as follows: initial [O]: 0.050%, [N]: 0.0013%, [S]: 0.0060%, no aluminum, and the weight of the molten steel is 300t;

[0055] (2) The target values of the main components of the molten steel after the converter of this steel grade are as follows: N: 0.015~0.020% (the lower limit value of 0.016% is taken as N (目标) ), Al: 0.045~0.06% (take the middle value 0.0525% as Al (目标) ), S≤0.0040%, T.[O]≤0.0025%;

[0056] (3) During the tapping process, argon is blown from the bottom of the ladle at a flow rate of 700 NL / min;

[0057] (4) When 1 / 10 of the steel is tapped, add low-quality aluminum ash to the molten steel at one time. The main components of the aluminum ash are 35% AlN and 15% elemental aluminum. The amount of aluminum ash added is W (铝灰) The calculation formula is as follows:

[0058] W (铝灰) =(0.016%-0.0013%)*300*10 3 / 35%*(41 / 14) / 60%=615kg;

[0059] (5) Oxygen consumption of AlN in low-quality aluminum ash [O] (AlN) The calculation formula is as follows:

[0060] [O] (AlN) =W (铝灰) *S (AlN) *60%*48 / 82 / molten steel volume=615*35%*60%*48 / 82 / (300*10 3 )*100%=0.025%

[0061] (6) Deoxidation of molten steel by elemental Al in low-quality aluminum ash [O] (铝灰) The calculation formula is as follows:

[0062] [O] (铝灰) =(W (铝灰) *15%*75%)*(48 / 54) / (300*10 3 )*100%=0.021%;

[0063] (7) When 1 / 4 of the steel is tapped, lime is added to the molten steel for desulfurization, with an addition amount of 8 kg / t steel;

[0064] (8) When 1 / 3 of the steel is tapped, aluminum particles are added to the molten steel for final deoxidation and aluminum alloying. The amount of aluminum particles added is calculated as follows:

[0065] W (铝粒) =((0.050%-0.025%-0.021%)*54 / 48+0.0525%)*300*10 3 / 78%=219kg;

[0066] (9) After the steel is tapped, add 350 kg of low-quality aluminum ash to the ladle top slag. The nitrogen generated by AlN increases the nitrogen content of the molten steel by (铝灰-渣) The calculation formula is as follows:

[0067] N (铝灰-渣) =350*35%*60%*(14 / 41)*30% / (300*10 3 )=0.0025%.

[0068] According to the above theoretical calculation, by adding low-quality aluminum ash to the molten steel and top slag, the endpoint nitrogen content of the molten steel is:

[0069] N (终点) =N (目标) +N (铝灰-渣) =0.016%+0.0025%=0.0185%.

[0070] Example 2

[0071] A low-sulfur, low-oxygen, high-nitrogen tinplate, the specific operation steps are as follows:

[0072] (1) Measure the composition of the molten steel at the converter end point, where the main components are as follows: initial [O]: 0.055%, N: 0.0015%, S: 0.0065%, no aluminum, and the weight of the molten steel is 300t;

[0073] (2) The target values of the main components of the molten steel after the converter of this steel grade are as follows: N: 0.018~0.025% (the lower limit value of 0.021% is taken as N (目标) ), Al: 0.06~0.08% (take the middle value 0.07% as Al (目标) ), S≤0.0035%, T.[O]≤0.0025%;

[0074] (3) During the tapping process, argon is blown from the bottom of the ladle at a flow rate of 700 NL / min;

[0075] (4) When 1 / 5 of the steel is tapped, add low-quality aluminum ash to the molten steel at one time. The main components of the aluminum ash are 38% AlN and 13% elemental aluminum. The amount of aluminum ash added is W (铝灰) The calculation formula is as follows:

[0076] W (铝灰) =(0.021%-0.0015%)*300*10 3 / 38%*(41 / 14) / 60%=751kg;

[0077] (5) Oxygen consumption of AlN in low-quality aluminum ash [O] (AlN) The calculation formula is as follows:

[0078] [O] (AlN) =751*38%*60%*48 / 82 / (300*10 3 )*100%=0.033%

[0079] (5) Deoxidation of molten steel by elemental Al in low-quality aluminum ash [O] (铝灰) The calculation formula is as follows:

[0080] [O] (铝灰) =(W (铝灰) *13%*75%)*(48 / 54) / (300*10 3 )*100%=0.022%;

[0081] (6) When 1 / 4 of the steel is tapped, lime is added to the molten steel for desulfurization, with an addition amount of 8.5 kg / t steel;

[0082] (7) When 1 / 2 of the steel is tapped, aluminum particles are added to the molten steel for final deoxidation and aluminum alloying. The amount of aluminum particles added is calculated as follows:

[0083] W (铝粒) =((0.055%-0.033%-0.022%)*54 / 48+0.07%)*300*10 3 / 78%=269kg;

[0084] (8) After the steel is tapped, low-quality aluminum ash is added to the ladle top slag in an amount of 380 kg. The nitrogen generated by AlN increases the nitrogen content of the molten steel by (铝灰-渣) The calculation formula is as follows:

[0085] N (铝灰-渣) =380*38%*60%*(14 / 41)*30% / (300*10 3 )=0.0029%.

[0086] According to the above theoretical calculation, by adding low-quality aluminum ash to the molten steel and top slag, the endpoint nitrogen content of the molten steel is:

[0087] N (终点) =N (目标) +N (铝灰-渣)=0.021%+0.0029%=0.0239%.

[0088] Example 3

[0089] A low-sulfur, low-oxygen, high-nitrogen tinplate, the specific operation steps are as follows:

[0090] (1) Measure the composition of the molten steel at the end of the converter, where the main components are as follows: initial [O]: 0.040%, N: 0.0020%, S: 0.0080%, no aluminum, and the weight of the molten steel is 300t;

[0091] (2) The target values of the main components of the molten steel after the converter of this steel grade are as follows: N: 0.013~0.016% (the lower limit value of 0.014% is taken as N (目标) ), Al: 0.04~0.06% (take the middle value 0.05% as Al (目标) ), S≤0.0035%, T.[O]≤0.0025%;

[0092] (3) During the tapping process, argon is blown from the bottom of the ladle at a flow rate of 700 NL / min;

[0093] (4) When 1 / 5 of the steel is tapped, add low-quality aluminum ash to the molten steel at one time. The main components of the aluminum ash are 45% AlN and 15% elemental aluminum. The amount of aluminum ash added is W (铝灰) The calculation formula is as follows:

[0094] W (铝灰) =(0.014%-0.0020%)*300*10 3 / 45%*(41 / 14) / 60%=390kg;

[0095] (5) Oxygen consumption of AlN in low-quality aluminum ash [O] (AlN) The calculation formula is as follows:

[0096] [O] (AlN) =390*45%*60%*48 / 82 / (300*10 3 )*100%=0.021%

[0097] (5) Deoxidation of molten steel by elemental Al in low-quality aluminum ash [O] (铝灰) The calculation formula is as follows:

[0098] [O] (铝灰) =(W (铝灰) *13%*75%)*(48 / 54) / (300*10 3 )*100%=0.011%;

[0099] (6) When 1 / 4 of the steel is tapped, lime is added to the molten steel for desulfurization, with an addition amount of 8.5 kg / t steel;

[0100] (7) When 1 / 2 of the steel is tapped, aluminum particles are added to the molten steel for final deoxidation and aluminum alloying. The amount of aluminum particles added is calculated as follows:

[0101] W (铝粒) =((0.040%-0.021%-0.011%)*54 / 48+0.05%)*300*10 3 / 78%=227kg;

[0102] (8) After the steel is tapped, add 200 kg of low-quality aluminum ash to the ladle top slag. The nitrogen generated by AlN increases the nitrogen content of the molten steel by (铝灰-渣) The calculation formula is as follows:

[0103] N (铝灰-渣) =200*45%*60%*(14 / 41)*30% / (300*10 3 )=0.0018%.

[0104] According to the above theoretical calculation, by adding low-quality aluminum ash to the molten steel and top slag, the endpoint nitrogen content of the molten steel is:

[0105] N (终点) =N (目标) +N (铝灰-渣) =0.014%+0.0018%=0.0158%.

[0106] Comparative Example 1-2

[0107] Comparative Examples 1 and 2 are both examples of producing high nitrogen steel using nitrogen, using aluminum pellets for final deoxidation and alloying. The initial conditions and final composition requirements of the molten steel are similar to those in the examples of this application.

[0108] The aluminum ash, aluminum particle consumption and main components of the steel plates of Examples 1-3 and Comparative Examples 1-2 are shown in the following table:

[0109]

[0110] As can be seen from the table above, the method provided in the examples of this application fully meets the target requirements for low-sulfur, low-oxygen, high-nitrogen tinplate. As can be seen from the comparative examples, the existing high-nitrogen steel production process usually uses RH process nitrogen injection to increase nitrogen, which can also achieve good nitrogen increase effects, but is greatly affected by the initial nitrogen content of the molten steel and the vacuum chamber pressure, and requires reasonable control. The final deoxidation and aluminum alloying of the molten steel are completely achieved by adding aluminum alloys such as aluminum particles and aluminum blocks, so the aluminum alloy consumption is large and the cost is high.

[0111] One or more technical solutions in the embodiments of the present invention may have at least the following technical effects or advantages:

[0112] (1) The method provided by the embodiment of the present invention provides a way to utilize low-quality aluminum ash, which can not only eliminate the environmental pollution caused by the accumulation of aluminum ash, but also achieve effective recycling of resources;

[0113] (2) The method provided by the embodiment of the present invention fully utilizes the characteristics of low-quality aluminum ash with high AlN content to achieve effective nitrogen addition to molten steel and significantly reduce production costs;

[0114] (3) The method provided by the embodiment of the present invention utilizes AlN in low-quality aluminum ash to nitrogenize molten steel, replacing the nitrogen-enhancing alloy. The small amount of elemental aluminum in the aluminum ash also has the effect of replacing part of the aluminum particles. At the same time, low-quality aluminum ash is cheaper than aluminum particles and nitrogen-containing alloys.

[0115] (4) The method provided by the embodiment of the present invention adds low-quality aluminum ash in the early stage of steel tapping, thereby partially deoxidizing the molten steel and reducing its oxidizability. When lime is subsequently added for desulfurization, the effect is better. The aluminum in the aluminum ash generates deoxidation products earlier, which have sufficient time to float up and be removed, making the molten steel cleaner.

[0116] (5) After the steel is tapped, the method provided in the embodiment of the present invention adds low-quality aluminum ash to the ladle top slag to completely replace the aluminum slag balls. AlN and metallic Al reduce the oxidizing property of the slag, which can further improve the cleanliness of the molten steel.

[0117] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0118] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0119] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet, characterized in that: The method comprises: The molten iron is subjected to converter smelting to obtain converter molten steel, and the components of the converter end-point molten steel are measured, including the initial O, initial Al, initial N, and initial S contents; tapping the converter molten steel to obtain tapped molten steel; Refining the molten steel and then continuously casting it to obtain a steel plate; Auxiliary materials are added during the steel tapping process, wherein the auxiliary materials include first aluminum ash, lime, and aluminum particles; In the first aluminum ash, the mass content of AlN is 30%≤≤50%, and the mass content of elemental Al is 10%≤≤20%; The first aluminum ash is added when the mass of the molten steel is 1 / 10-1 / 5, and the amount of the first aluminum ash added is W (第一铝灰) W (第一铝灰) =(N (目标) -N (初始) )*molten steel weight / (S (AlN) *(41 / 14) / AlN absorption rate, where N (初始) is the initial nitrogen content of molten steel, N (目标) The lower and middle values of the target range of molten steel N content, S (AlN) is the proportion of AlN in the first aluminum ash; The lime is added when the mass of the molten steel is 1 / 5-1 / 3, and the amount of lime added is 6kg / t steel-10kg / t steel; The timing of adding the aluminum particles is when the mass of the molten steel is 1 / 3-1 / 2, and the amount of the aluminum particles added is W (铝粒) W (铝粒) =(([O]0-[O] (AlN) -[O] (第一铝灰) )*54 / 48+Al (目标) -Al (初始) )*weight of molten steel / alloy yield of aluminum particles, where [O]0 is the initial oxygen content of the molten steel, [O] (AlN) is the amount of oxygen consumed by the AlN reaction in the first aluminum ash, [O] (第一铝灰) is the deoxidation amount of elemental aluminum in the first aluminum ash, Al (目标) The middle value of the target Al content range of the molten steel end point, Al (初始) is the initial Al content of molten steel; The method further comprises: adding a second aluminum ash to the surface of the ladle top slag after the steel tapping is completed, wherein the amount of the second aluminum ash added is 200kg-600kg.

2. The method for preparing a low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet according to claim 1, characterized in that: During the steel tapping process, the ladle is bottom-blown with argon, and the flow rate of the bottom-blown argon is 600NL / min-1000NL / min.

3. The method for preparing a low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet according to claim 1, characterized in that: The chemical composition of the steel plate includes, by mass fraction, C: 0.05%-0.09%, Si: ≤0.05%, Mn: 0.3%-0.5%, P: ≤0.012%, S: ≤0.004%, Al: 0.04%-0.08%, N: 0.013%-0.025%, and TO: ≤0.0025%.

4. A low-sulfur, low-oxygen, high-nitrogen tin-plated steel sheet, characterized in that: The steel plate is prepared by the method for preparing a low-sulfur, low-oxygen, high-nitrogen tin-plated steel plate according to any one of claims 1 to 3.

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