A method for calculating the amount of aluminum added in the refining of low-carbon, low-silicon, aluminum-killed steel LF.

Abstract

This invention provides a method for calculating the amount of aluminum wire added during the refining of low-carbon, low-silicon, aluminum-killed steel (LF), relating to the technical field of iron and steel metallurgy. The method involves the following steps: First, the acid-soluble aluminum content of the molten steel sample from the converter ladle is obtained, and the initial amount of aluminum wire added, M, is determined based on this content. Then, the sulfur content, acid-soluble aluminum content, and weight of the molten steel entering the LF refining station are obtained to establish a calculation model for the first aluminum wire addition, determining the initial addition amount M1. After the LF completes its initial heating and slag-forming operations, the acid-soluble aluminum content during the LF refining process is obtained, and a second aluminum wire addition model is established based on the target acid-soluble aluminum content and aluminum wire yield, determining the second addition amount M2. This method facilitates accurate control of the acid-soluble aluminum content in the molten steel during the LF refining process, reduces production costs, improves steel quality, has a wide range of applications, and is suitable for large-scale industrial production and widespread use.

Description

Technical Field

[0001] This invention relates to the technical field of iron and steel metallurgy, and in particular to a method for calculating the amount of aluminum added in the LF refining process of low-carbon, low-silicon, aluminum-killed steel. Background Technology

[0002] High-end, intelligent, and green development have become the main trends in the steel industry. In the LF refining process, a higher acid-soluble aluminum content in the molten steel results in lower dissolved oxygen levels, which is beneficial for improving steel quality. However, for low-carbon, low-silicon, aluminum-killed steel, a high acid-soluble aluminum content in the molten steel during LF refining may lead to excessive silicon content and increased production costs. Therefore, precise control of the acid-soluble aluminum content in the molten steel plays a crucial role in improving steel quality and reducing production costs.

[0003] LF refining involves complex high-temperature physicochemical reactions. In actual production, the amount of aluminum wire added and the content of aluminum dissolved in molten steel are usually controlled based on the experience of technicians and multiple sampling. For example, Chinese patent CN115386680A discloses a method for precisely controlling the [Al] content in molten steel at the end of the LF furnace. Based on the LIBS online steel composition detection system, it establishes an aluminum wire feeding model to guide the wire feeding operation by analyzing the linear decay rate of [Al] in the steel over time through multiple uniform intervals, thereby achieving precise control of the [Al] content in the LF furnace refining process and the final molten steel. Chinese patent CN111455137A discloses a method for precisely controlling the amount of aluminum used in IF steel. However, the amount of aluminum added is determined by adding 120 ppm of the lower limit of Al in the steel grade, based on the addition of high-carbon ferromanganese during RH decarburization. Patent CN116536479A discloses a method for precisely controlling the aluminum content at the end point of an LF furnace for medium and high carbon aluminum-killed steel. This method involves aluminum-iron alloying treatment, adding aluminum particles to the slag surface for deoxidation during LF furnace entry, and feeding a certain amount of aluminum wire into the molten steel for deoxidation during exit. Meanwhile, articles such as "Research and Application of Precision Wire Feeding Technology for 80-ton LF", "Control of Acid-Soluble Aluminum in CSP Steel at Lianyuan Steel", and "Research on ALS Control Process of Converter-CSP Steel" analyze the influence of different factors on the acid-soluble aluminum content of molten steel from different perspectives, including thermodynamics, kinetics, and production practice, and derive the amount of aluminum to be added within different ranges of carbon content, acid-soluble aluminum content, and free oxygen content in molten steel.

[0004] However, a literature review revealed that most publicly available studies qualitatively analyzed the impact of different factors on the aluminum content of molten steel. A few studies, based on on-site production experience, controlled the amount of aluminum to be added by using the range of other components in molten steel. This made it impossible to accurately control the acid-soluble aluminum content in molten steel during actual production, resulting in large fluctuations in the composition of molten steel, which is not conducive to the development of LF intelligent refining.

[0005] In particular, Chinese patent CN106191376A discloses a vacuum carbonization pre-deoxidation process for ultra-low carbon aluminum-killed steel. This process calculates the amount of aluminum shot to be added based on the oxygen determination results. The amount of aluminum shot added is calculated by using the aluminum-oxygen balance reaction formula and the burn-off amount. 100 kg of aluminum shot deoxidizes 100 ppm. Obviously, this provides technical inspiration for the addition of aluminum shot and the calculation method. The method of adding aluminum is not precise, and the control of aluminum content in the molten steel is poor, which affects the performance of the killed steel.

[0006] Chinese patent CN112267000A discloses a short-process technology for producing low-carbon, low-silicon aluminum-killed steel. This process involves adding an aluminum-iron alloy for deoxidation and alloying during converter smelting. After the aluminum-iron alloy is added, 200-400 kg of lime, 100-200 kg of fluorite, and 100-200 kg of medium-aluminum slag balls are added when the steel is tapped to one-third of its length. After tapping, the slag surface is blown open, and aluminum wire is fed in to achieve the target aluminum content. Clearly, the amount of aluminum wire added is determined by achieving the target aluminum content, which is determined by detecting the composition of the molten steel. Due to the uneven distribution of the steel composition, some areas may reach the target while others do not, resulting in large fluctuations in the content values ​​of the steel composition across different areas. Summary of the Invention

[0007] The technical problem this invention aims to solve is that the amount of aluminum added in the current aluminum-killed steel LF refining line is controlled based on the experience of technicians and multiple sampling. Although the influence of factors on the acid-soluble aluminum content of molten steel has been analyzed from different perspectives, some studies only conduct qualitative analysis on the influence of aluminum content in molten steel, while others require combining on-site production practice and indirectly controlling the amount of aluminum added by controlling the content of other components in molten steel. The control method is not direct and cannot achieve precise control, resulting in large differences in the component content of different parts of molten steel, which is not conducive to the large-scale production and promotion of intelligent refining of industrial LF.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] A method for calculating the amount of low-carbon, low-silicon, aluminum-killed steel LF refining aluminum wire added, the method comprising the following steps:

[0010] S1. Obtain the acid-soluble aluminum content of the molten steel composition of the converter ladle sample, and determine the initial addition amount M of aluminum wire based on the acid-soluble aluminum content;

[0011] S2. Obtain the sulfur content, acid-soluble aluminum content, and steel weight of the molten steel entering the LF refining station, and establish a calculation model for the first aluminum wire addition amount to determine the first aluminum wire addition amount M1.

[0012] S3. After the initial heating and slag-forming operations of LF are completed, the acid-soluble aluminum content during the LF refining process is obtained, and a model for the second aluminum wire addition is established in combination with the target acid-soluble aluminum content and aluminum wire yield to determine the second aluminum wire addition amount M2.

[0013] Optionally, S1 also includes a step of adding aluminum wire after the converter tapping and before the start of LF refining, in order to control the acid-soluble aluminum content in the molten steel entering the LF refining station to be 0.02-0.04%.

[0014] Optionally, the method for determining the initial addition amount of aluminum wire in S1 based on the acid-soluble aluminum content is as follows: establish a rating standard for the oxidizability of molten steel, determine the rating of the oxidizability of molten steel based on the acid-soluble aluminum content, and determine the initial addition amount of aluminum wire based on the rating of the oxidizability of molten steel.

[0015] Optionally, a rating standard for the oxidizability of molten steel can be established in S1:

[0016] Very strong: w[Als] 转炉包样 ≤0.03

[0017] Strong: 0.03 < w[Als] 转炉包样 ≤0.04

[0018] In the middle: 0.04 < w[Als] 转炉包样 ≤0.06

[0019] Weak: w[Als] 转炉包样 >0.06,

[0020] In the formula, w[Als] 转炉包样 The content of acid-soluble aluminum in the converter ladle sample is expressed in %; very strong indicates that the molten steel has very strong oxidizing properties; strong indicates that the molten steel has relatively strong oxidizing properties; medium indicates that the molten steel has a moderate degree of oxidizing properties; weak indicates that the molten steel has very weak oxidizing properties.

[0021] Optionally, the unit weight of aluminum wire is 0.33 kg / m; when the oxidizing power rating of molten steel in S1 is very strong, the initial addition amount M of aluminum wire is 300 m; when the oxidizing power rating of molten steel in S1 is strong, the initial addition amount M of aluminum wire is 200 m; when the oxidizing power rating of molten steel in S1 is medium, the initial addition amount M of aluminum wire is 100 m; when the oxidizing power rating of molten steel in S1 is weak, the initial addition amount M of aluminum wire is 0 m.

[0022] Optionally, the specific calculation model for the amount of aluminum wire added in S2 is as follows:

[0023] M1 = a + bG + cw[S] 进站 +dw[Als] 进站

[0024] In the formula, M1 is the amount of aluminum wire added initially; G is the weight of molten steel in kg; w[S] 进站 The sulfur content of molten steel entering the LF refining station is expressed in %; w[Als] 进站 The denominator represents the acid-soluble aluminum content of the molten steel entering the LF refining station, in %; a is a constant term; b is the weighting coefficient of the molten steel weight; c is the weighting coefficient of the sulfur content of the molten steel entering the LF refining station; d is the weighting coefficient of the acid-soluble aluminum content of the molten steel entering the LF refining station.

[0025] Optionally, in S2, the Al content w[Als] in the converter ladle sample steel is... 转炉包样 When < 0.03, a = -49.365, b = 1.259‰, c = 1125.23, d = -2183.974; when 0.03 ≤ w[Als] 转炉包样 When w[Als] ≤ 0.04, a = 194.028, b = 0.394‰, c = 1574.27, d = -3493.996; 转炉包样 When the value is greater than 0.04, a = 207.832, b = 0.329‰, c = 2796.3, and d = -4088.307.

[0026] Optionally, the specific model for the second aluminum wire addition in S3 is as follows:

[0027]

[0028] In the formula, M2 is the amount of aluminum wire added in the second step, in meters; Δ[Als] represents the difference between the acid-soluble aluminum content in the steel sample and the target acid-soluble aluminum content in the molten steel during the LF refining process, in percentage. This indicates the aluminum wire yield at this step, expressed as a percentage.

[0029] Optionally, the target acid-soluble aluminum content in the molten steel in S3 is 0.025-0.035%.

[0030] Optionally, the aluminum wire yield in S3

[0031] Optionally, the calculation method for the amount of aluminum added in the LF refining of low-carbon, low-silicon, aluminum-killed steel can control the acid-soluble aluminum content in the molten steel at the end of the LF refining process within ±0.003% based on the actual working conditions of LF refining, which is beneficial to achieving precise control of the acid-soluble aluminum content in the LF refining molten steel.

[0032] The above technical solution has at least the following advantages compared with the existing technology:

[0033] The present invention proposes a method for calculating the amount of aluminum added to the LF refining process of low-carbon, low-silicon aluminum-killed steel, in order to overcome the technical defect that the amount of aluminum added to the LF refining process of aluminum-killed steel was controlled based on the experience of technicians and multiple sampling, which made it impossible to accurately control the acid-soluble aluminum content in molten steel in actual production.

[0034] This invention uses a method to determine the amount of aluminum wire added in three stages to precisely control the acid-soluble aluminum content in LF steel, resulting in a uniform distribution of steel composition throughout the molten steel.

[0035] The initial amount of aluminum wire added in this invention is determined by establishing a rating standard for the oxidizability of molten steel. This rating serves to coarsely adjust the acid-soluble aluminum content, controlling it within the range of 0.02-0.04%. The first aluminum wire addition amount is calculated using a model based on the sulfur content, acid-soluble aluminum content, and weight of the molten steel entering the LF refining station, enabling precise control of these contents. The second aluminum wire addition amount is calculated using a model based on the acid-soluble aluminum content during the LF refining process, combined with the target acid-soluble aluminum content and aluminum wire yield, allowing for even more precise control of the sulfur and acid-soluble aluminum content in the molten steel.

[0036] In summary, compared with other traditional methods, the method of this invention can accurately calculate the amount of aluminum wire added based on the actual on-site production conditions, the smelting requirements of the target steel grade, and the changes in the composition of molten steel at different stages. This method is beneficial for accurately controlling the acid-soluble aluminum content of molten steel in the LF refining process, reducing production costs, improving the quality of molten steel, and has a wide range of applications, making it suitable for large-scale industrial production and widespread use. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a process flow diagram illustrating the method for calculating the amount of aluminum added in the LF refining process of low-carbon, low-silicon aluminum-killed steel according to the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] A method for calculating the amount of low-carbon, low-silicon, aluminum-killed steel LF refining aluminum wire added, wherein the method for calculating the amount of low-carbon, low-silicon, aluminum-killed steel LF refining aluminum wire added is combined with Figure 1 The following steps are required:

[0041] S1. Obtain the acid-soluble aluminum content of the molten steel composition of the converter ladle sample, and determine the initial addition amount M of aluminum wire based on the acid-soluble aluminum content;

[0042] S2. Obtain the sulfur content, acid-soluble aluminum content, and steel weight of the molten steel entering the LF refining station, and establish a calculation model for the first aluminum wire addition amount to determine the first aluminum wire addition amount M1.

[0043] S3. After the initial heating and slag-forming operations of LF are completed, the acid-soluble aluminum content during the LF refining process is obtained, and a model for the second aluminum wire addition is established in combination with the target acid-soluble aluminum content and aluminum wire yield to determine the second aluminum wire addition amount M2.

[0044] Specifically, S1 also includes the step of adding aluminum wire after the converter tapping and before the start of LF refining, in order to control the acid-soluble aluminum content in the molten steel entering the LF refining station to be 0.02-0.04%.

[0045] Specifically, the method for determining the initial addition amount of aluminum wire in S1 based on the acid-soluble aluminum content is as follows: establish a rating standard for the oxidizability of molten steel, determine the rating of the oxidizability of molten steel based on the acid-soluble aluminum content, and determine the initial addition amount of aluminum wire based on the rating of the oxidizability of molten steel.

[0046] Specifically, S1 establishes a rating standard for the oxidizability of molten steel:

[0047] Very strong: w[Als] 转炉包样 ≤0.03

[0048] Strong: 0.03 < w[Als] 转炉包样 ≤0.04

[0049] In the middle: 0.04 < w[Als] 转炉包样 ≤0.06

[0050] Weak: w[Als] 转炉包样 >0.06,

[0051] In the formula, w[Als] 转炉包样 The content of acid-soluble aluminum in the converter ladle sample is expressed in %; very strong indicates that the molten steel has very strong oxidizing properties; strong indicates that the molten steel has relatively strong oxidizing properties; medium indicates that the molten steel has a moderate degree of oxidizing properties; weak indicates that the molten steel has very weak oxidizing properties.

[0052] Specifically, the unit weight of aluminum wire is 0.33 kg / m; when the oxidizing power rating of molten steel in S1 is very strong, the initial addition amount M of aluminum wire is 300 m; when the oxidizing power rating of molten steel in S1 is strong, the initial addition amount M of aluminum wire is 200 m; when the oxidizing power rating of molten steel in S1 is medium, the initial addition amount M of aluminum wire is 100 m; when the oxidizing power rating of molten steel in S1 is weak, the initial addition amount M of aluminum wire is 0 m.

[0053] Specifically, the calculation model for the amount of aluminum wire added in S2 is as follows:

[0054] M1 = a + bG + cw[S] 进站 +dw[Als] 进站

[0055] In the formula, M1 is the amount of aluminum wire added initially; G is the weight of molten steel in kg; w[S] 进站 The sulfur content of molten steel entering the LF refining station is expressed in %; w[Als] 进站 The denominator represents the acid-soluble aluminum content of the molten steel entering the LF refining station, in %; a is a constant term; b is the weighting coefficient of the molten steel weight; c is the weighting coefficient of the sulfur content of the molten steel entering the LF refining station; d is the weighting coefficient of the acid-soluble aluminum content of the molten steel entering the LF refining station.

[0056] Specifically, in S2, the Al content w[Als] in the converter ladle steel sample... 转炉包样 When < 0.03, a = -49.365, b = 1.259‰, c = 1125.23, d = -2183.974; when 0.03 ≤ w[Als] 转炉包样 When w[Als] ≤ 0.04, a = 194.028, b = 0.394‰, c = 1574.27, d = -3493.996; 转炉包样 When the value is greater than 0.04, a = 207.832, b = 0.329‰, c = 2796.3, and d = -4088.307.

[0057] Specifically, the model for the second aluminum wire addition in S3 is as follows:

[0058]

[0059] In the formula, M2 is the amount of aluminum wire added in the second step, in meters; Δ[Als] represents the difference between the acid-soluble aluminum content in the steel sample and the target acid-soluble aluminum content in the molten steel during the LF refining process, in percentage. This indicates the aluminum wire yield at this step, expressed as a percentage.

[0060] Specifically, the target acid-soluble aluminum content in the molten steel of S3 is 0.025-0.035%.

[0061] Specifically, the aluminum wire yield in S3

[0062] In particular, the calculation method for the amount of aluminum added in the LF refining process of low-carbon, low-silicon aluminum-killed steel can control the acid-soluble aluminum content in the molten steel at the end of the LF refining process within ±0.003% based on the actual working conditions of LF refining, which is beneficial to achieving precise control of the acid-soluble aluminum content in the molten steel of LF refining.

[0063] Examples 1-8

[0064] A method for calculating the amount of aluminum added in the LF refining process of low-carbon, low-silicon, aluminum-killed steel is disclosed. This method is implemented using a 150t LF refining furnace in a steel plant producing SPHC steel as an example. The calculation method for the amount of aluminum added in the LF refining process of low-carbon, low-silicon, aluminum-killed steel is as follows:

[0065] S1. Obtain the acid-soluble aluminum content of the molten steel sample from the converter ladle. Control the Al content in the LF refining molten steel to be 0.02-0.04%. Establish a rating standard for the oxidizability of the molten steel based on the acid-soluble aluminum content. Determine the rating of the oxidizability of the molten steel based on the rating of the molten steel's oxidation state. The initial addition amount M of aluminum wire is determined based on the rating of the molten steel's oxidation state. Details are as follows:

[0066] Establish rating standards for the oxidizability of molten steel:

[0067] Very strong: w[Als] 转炉包样 ≤0.03

[0068] Strong: 0.03 < w[Als] 转炉包样 ≤0.04

[0069] In the middle: 0.04 < w[Als] 转炉包样 ≤0.06

[0070] Weak: w[Als] 转炉包样 >0.06,

[0071] In the formula, w[Als] 转炉包样 The content of acid-soluble aluminum in the converter ladle sample is expressed in %; "Very strong" indicates that the molten steel has very strong oxidizing properties; "Strong" indicates that the molten steel has relatively strong oxidizing properties; "Medium" indicates that the molten steel has a moderate degree of oxidizing properties; "Weak" indicates that the molten steel has very weak oxidizing properties.

[0072] The unit weight of aluminum wire is 0.33 kg / m; when the oxidizing power rating of molten steel in S1 is very strong, the initial addition amount M of aluminum wire is 300 m; when the oxidizing power rating of molten steel in S1 is strong, the initial addition amount M of aluminum wire is 200 m; when the oxidizing power rating of molten steel in S1 is medium, the initial addition amount M of aluminum wire is 100 m; when the oxidizing power rating of molten steel in S1 is weak, the initial addition amount M of aluminum wire is 0 m.

[0073] S2. Obtain the sulfur content, acid-soluble aluminum content, and weight of the molten steel entering the LF refining station. Use this information to establish a calculation model for the initial aluminum wire addition amount, and determine the initial aluminum wire addition amount M1; details are as follows:

[0074] The specific steps for establishing the calculation model for the amount of aluminum wire added are as follows:

[0075] M1 = a + bG + cw[S] 进站 +dw[Als] 进站

[0076] In the formula, M1 is the amount of aluminum wire added initially; G is the weight of molten steel in kg; w[S] 进站 The sulfur content of molten steel entering the LF refining station is expressed in %; w[Als] 进站 The LF refining process introduces the acid-soluble aluminum content of the molten steel entering the station, in %; a is a constant term; b is the weighting coefficient of the molten steel weight; c is the weighting coefficient of the S content of the LF refining process entering the station; d is the weighting coefficient of the acid-soluble aluminum content of the LF refining process entering the station.

[0077] When the Al content w[Als] in the converter ladle steel sample 转炉包样 When < 0.03, a = -49.365, b = 1.259‰, c = 1125.23, d = -2183.974; when 0.03 ≤ w[Als] 转炉包样 When w[Als] ≤ 0.04, a = 194.028, b = 0.394‰, c = 1574.27, d = -3493.996; 转炉包样 When the value is greater than 0.04, a = 207.832, b = 0.329‰, c = 2796.3, and d = -4088.307.

[0078] S3. After the initial heating and slag-forming operations of LF are completed, obtain the acid-soluble aluminum content during the LF refining process. The target acid-soluble aluminum content in the molten steel is 0.03%, and the aluminum wire yield is... A model for the second addition of aluminum wire was established by combining the target acid-soluble aluminum content and aluminum wire yield to determine the amount of aluminum wire added, M2; the details are as follows:

[0079] The specific model for the second aluminum wire addition is as follows:

[0080]

[0081] In the formula, M2 is the amount of aluminum wire added in the second step, in meters; Δ[Als] represents the difference between the acid-soluble aluminum content in the steel sample and the target acid-soluble aluminum content in the molten steel during the LF refining process, in percentage. This indicates the aluminum wire yield at this step, expressed as a percentage.

[0082] The calculation method for the amount of aluminum added in the LF refining process of low-carbon, low-silicon aluminum-killed steel can control the acid-soluble aluminum content in the molten steel at the end of the LF refining process within ±0.003% based on the actual working conditions of LF refining, which is conducive to achieving precise control of the acid-soluble aluminum content in the molten steel of LF refining.

[0083] The relevant experimental data and results of Examples 1-8 are shown in Table 1 below.

[0084] Table 1. Experimental results of Examples 1-8

[0085]

[0086] In the comparative example, before applying the method of this invention, 150m of aluminum wire was uniformly added to the ladles before entering the LF refining station, followed by additional aluminum wire based on experience. However, in actual production, due to differences in operation among different shifts, the amount of aluminum wire added varied significantly, leading to large fluctuations in the acid-soluble aluminum content in the molten steel across different shifts. The relevant experimental data and results of Comparative Example 1 are shown in Table 2 below.

[0087] Table 2 shows the experimental results of Comparative Example 1.

[0088]

[0089] Examples 9-14

[0090] A method for calculating the amount of aluminum added in the LF refining process of low-carbon, low-silicon, aluminum-killed steel is disclosed. This method is implemented using a 150t LF refining furnace in a steel plant producing SPHC steel as an example. The calculation method for the amount of aluminum added in the LF refining process of low-carbon, low-silicon, aluminum-killed steel is as follows:

[0091] S1. Obtain the acid-soluble aluminum content of the molten steel sample from the converter ladle. Control the Al content in the LF refining molten steel to be 0.02-0.04%. Establish a rating standard for the oxidizability of the molten steel based on the acid-soluble aluminum content. Determine the rating of the oxidizability of the molten steel based on the rating of the molten steel's oxidation state. The initial addition amount M of aluminum wire is determined based on the rating of the molten steel's oxidation state. Details are as follows:

[0092] Establish rating standards for the oxidizability of molten steel:

[0093] Very strong: w[Als] 转炉包样 ≤0.03

[0094] Strong: 0.03 < w[Als] 转炉包样 ≤0.04

[0095] In the middle: 0.04 < w[Als] 转炉包样 ≤0.06

[0096] Weak: w[Als] 转炉包样 >0.06,

[0097] In the formula, w[Als] 转炉包样 The content of acid-soluble aluminum in the converter ladle sample is expressed in %; "Very strong" indicates that the molten steel has very strong oxidizing properties; "Strong" indicates that the molten steel has relatively strong oxidizing properties; "Medium" indicates that the molten steel has a moderate degree of oxidizing properties; "Weak" indicates that the molten steel has very weak oxidizing properties.

[0098] The unit weight of aluminum wire is 0.33 kg / m; when the oxidizing power rating of molten steel in S1 is very strong, the initial addition amount M of aluminum wire is 300 m; when the oxidizing power rating of molten steel in S1 is strong, the initial addition amount M of aluminum wire is 200 m; when the oxidizing power rating of molten steel in S1 is medium, the initial addition amount M of aluminum wire is 100 m; when the oxidizing power rating of molten steel in S1 is weak, the initial addition amount M of aluminum wire is 0 m.

[0099] S2. Obtain the sulfur content, acid-soluble aluminum content, and weight of the molten steel entering the LF refining station. Use this information to establish a calculation model for the initial aluminum wire addition amount, and determine the initial aluminum wire addition amount M1; details are as follows:

[0100] The specific steps for establishing the calculation model for the amount of aluminum wire added are as follows:

[0101] M1 = a + bG + cw[S] 进站 +dw[Als] 进站

[0102] In the formula, M1 is the amount of aluminum wire added initially; G is the weight of molten steel in kg; w[S] 进站 The sulfur content of molten steel entering the LF refining station is expressed in %; w[Als] 进站 The LF refining process introduces the acid-soluble aluminum content of the molten steel entering the station, in %; a is a constant term; b is the weighting coefficient of the molten steel weight; c is the weighting coefficient of the S content of the LF refining process entering the station; d is the weighting coefficient of the acid-soluble aluminum content of the LF refining process entering the station.

[0103] When the Al content w[Als] in the converter ladle steel sample 转炉包样 When < 0.03, a = -49.365, b = 1.259‰, c = 1125.23, d = -2183.974; when 0.03 ≤ w[Als] 转炉包样 When w[Als] ≤ 0.04, a = 194.028, b = 0.394‰, c = 1574.27, d = -3493.996; 转炉包样 When the value is greater than 0.04, a = 207.832, b = 0.329‰, c = 2796.3, and d = -4088.307.

[0104] S3. After the initial heating and slag-forming operations of LF are completed, obtain the acid-soluble aluminum content during the LF refining process. The target acid-soluble aluminum content in the molten steel is 0.025%, and the aluminum wire yield is... A model for the second addition of aluminum wire was established by combining the target acid-soluble aluminum content and aluminum wire yield to determine the amount of aluminum wire added, M2; the details are as follows:

[0105] The specific model for the second aluminum wire addition is as follows:

[0106]

[0107] In the formula, M2 is the amount of aluminum wire added in the second step, in meters; Δ[Als] represents the difference between the acid-soluble aluminum content in the steel sample and the target acid-soluble aluminum content in the molten steel during the LF refining process, in percentage. This indicates the aluminum wire yield at this step, expressed as a percentage.

[0108] The calculation method for the amount of aluminum added in the LF refining process of low-carbon, low-silicon aluminum-killed steel can control the acid-soluble aluminum content in the molten steel at the end of the LF refining process within ±0.003% based on the actual working conditions of LF refining, which is conducive to achieving precise control of the acid-soluble aluminum content in the molten steel of LF refining.

[0109] The relevant experimental data and results of Examples 9-14 are shown in Table 3 below.

[0110] Table 3 Experimental results of Examples 9-14

[0111]

[0112] In the comparative example, before applying the method of this invention, 150m of aluminum wire was uniformly added to the ladles before entering the LF refining station, followed by additional aluminum wire based on experience. However, in actual production, due to differences in operation among different shifts, the amount of aluminum wire added varied significantly, leading to large fluctuations in the acid-soluble aluminum content in the molten steel across different shifts. The relevant experimental data and results of Comparative Example 2 are shown in Table 4 below.

[0113] Table 4 shows the experimental results of Comparative Example 2.

[0114]

[0115] The present invention proposes a method for calculating the amount of aluminum added to the LF refining process of low-carbon, low-silicon aluminum-killed steel, in order to overcome the technical defect that the amount of aluminum added to the LF refining process of aluminum-killed steel was controlled based on the experience of technicians and multiple sampling, which made it impossible to accurately control the acid-soluble aluminum content in molten steel in actual production.

[0116] This invention uses a method to determine the amount of aluminum wire added in three stages to precisely control the acid-soluble aluminum content in LF steel, resulting in a uniform distribution of steel composition throughout the molten steel.

[0117] The initial amount of aluminum wire added in this invention is determined by establishing a rating standard for the oxidizability of molten steel. This rating serves to coarsely adjust the acid-soluble aluminum content, controlling it within the range of 0.02-0.04%. The first aluminum wire addition amount is calculated using a model based on the sulfur content, acid-soluble aluminum content, and weight of the molten steel entering the LF refining station, enabling precise control of these contents. The second aluminum wire addition amount is calculated using a model based on the acid-soluble aluminum content during the LF refining process, combined with the target acid-soluble aluminum content and aluminum wire yield, allowing for even more precise control of the sulfur and acid-soluble aluminum content in the molten steel.

[0118] In summary, compared with other traditional methods, the method of this invention can accurately calculate the amount of aluminum wire added based on the actual on-site production conditions, the smelting requirements of the target steel grade, and the changes in the composition of molten steel at different stages. This method is beneficial for accurately controlling the acid-soluble aluminum content of molten steel in the LF refining process, reducing production costs, improving the quality of molten steel, and has a wide range of applications, making it suitable for large-scale industrial production and widespread use.

[0119] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for calculating the LF refining aluminum wire addition amount of low-carbon low-silicon aluminum killed steel, characterized by, The calculation method for the amount of low-carbon, low-silicon aluminum-killed steel LF refining aluminum wire added is as follows: S1. Obtain the acid-soluble aluminum content of the molten steel composition of the converter ladle sample, and determine the initial addition amount M of aluminum wire based on the acid-soluble aluminum content; the method for determining the initial addition amount of aluminum wire based on the acid-soluble aluminum content is as follows: establish a rating standard for the oxidizability of molten steel, determine the rating of the oxidizability of molten steel based on the acid-soluble aluminum content, and determine the initial addition amount of aluminum wire based on the rating of the oxidizability of molten steel. Establish rating standards for the oxidizability of molten steel: ， wherein w For the content of acid-soluble aluminum in the ladle sample, the unit is %; very strong indicates that the molten steel has very strong oxidizing property; strong indicates that the molten steel has relatively strong oxidizing property; medium indicates that the molten steel has medium oxidizing property; weak indicates that the oxidizing property of the molten steel is very weak; S2. Obtain the sulfur content, acid-soluble aluminum content, and steel weight of the molten steel entering the LF refining station, and establish a calculation model for the first aluminum wire addition amount to determine the first aluminum wire addition amount M1. The specific steps for establishing the calculation model for the amount of aluminum wire added are as follows: wherein, is the first aluminum wire addition amount; is the molten steel weight, in kg; w is the sulfur content of the molten steel entering the LF refining station, in %; w is the acid-soluble aluminum content of the molten steel entering the LF refining station, in %; is the constant term; is the weight coefficient of the molten steel weight; is the weight coefficient of the sulfur content of the molten steel entering the LF refining station; is the weight coefficient of the acid-soluble aluminum content of the molten steel entering the LF refining station; S3. After the initial heating and slag-forming operations of the LF are completed, the acid-soluble aluminum content during the LF refining process is obtained. A second aluminum wire addition model is established based on the target acid-soluble aluminum content and the aluminum wire yield. The specific model for the second aluminum wire addition is as follows: In the formula, is the second aluminum wire addition amount, unit: m; represents the difference between the content of acid-soluble aluminum in the LF refining process steel sample and the target acid-soluble aluminum content of the molten steel, unit: %; represents the aluminum wire yield at this step, unit: %. Determine the amount of aluminum wire added for the second time, M2.

2. The method for calculating the amount of low-carbon, low-silicon aluminum-killed steel LF refining aluminum wire added according to claim 1, characterized in that, S1 also includes the step of adding aluminum wire after the converter tapping and before the start of LF refining, in order to control the acid-soluble aluminum content in the molten steel entering the LF refining station to be 0.02-0.04%.

3. The method for calculating the amount of low-carbon, low-silicon aluminum-killed steel LF refining aluminum wire added according to claim 1, characterized in that, The unit weight of aluminum wire is 0.33 kg / m; when the oxidizing power rating of molten steel in S1 is very strong, the initial addition amount of aluminum wire M is 300 m; when the oxidizing power rating of molten steel in S1 is strong, the initial addition amount of aluminum wire M is 200 m; when the oxidizing power rating of molten steel in S1 is medium, the initial addition amount of aluminum wire M is 100 m; when the oxidizing power rating of molten steel in S1 is weak, the initial addition amount of aluminum wire M is 0 m.

4. The method for calculating the amount of low-carbon, low-silicon aluminum-killed steel LF refining aluminum wire added according to claim 1, characterized in that, In S2, the Al content in the converter ladle sample steel hour, =-49.365、 =1.259‰ =1125.23、 =-2183.974; when hour, =194.028、 =0.394‰ =1574.27、 =-3493.996; when hour, =207.832、 =0.329‰ =2796.3、 =-4088.

307.

5. The method for calculating the amount of low-carbon, low-silicon aluminum-killed steel LF refining aluminum wire added according to claim 1, characterized in that, The target acid-soluble aluminum content in molten steel in S3 is 0.025-0.035%.

6. The method for calculating the amount of low-carbon, low-silicon aluminum-killed steel LF refining aluminum wire added according to claim 1, characterized in that, S3 aluminum wire yield =70%.

Images