Production method and control system for precise control of thermal balance under high-speed rail steel ratio mode

Abstract

This invention provides a production method and control system for precisely controlling thermal balance under high-iron steel ratio conditions, belonging to the field of converter steelmaking technology. The method includes: S1. Determining the charging regime for molten iron and scrap steel; S2. Calculating the amount of lime base added; S3. Measuring the temperature drop coefficients of various materials and updating them to the sub-lance model, synchronously adjusting model parameters to adapt to the high-iron steel ratio; S4. Utilizing an optimized sub-lance "temperature control module," comparing the temperature drop caused by static thermal balance and dynamic cumulative charging in real time, guiding the precise addition of iron-containing secondary resources such as magnetic separation powder and cold-pressed balls to absorb excess heat. This invention solves the problems of splashing, high consumption, and low hit rate caused by excess heat in the converter under high-iron steel ratio conditions, achieving precise control of process temperature, improving the endpoint hit rate and the first-time tapping rate, effectively reducing the consumption of steel materials and flux, and achieving the goal of cost reduction and efficiency improvement.

Description

Technical Field

[0001] This invention relates to the field of converter steelmaking technology, and in particular to a production method and control system for precisely controlling thermal balance under a high-speed rail steel ratio mode. Background Technology

[0002] Currently, the steel industry is facing cyclical downward pressure, characterized by reduced supply, shrinking demand, rising costs, and declining profits. To cope with losses, many steel companies have adopted measures to reduce output and control costs, including increasing blast furnace iron production and reducing the amount of scrap steel added to converters—essentially increasing the iron-to-steel ratio. Under this model, the amount of molten iron entering the converter increases significantly, while the amount of cold materials such as scrap steel decreases, resulting in a large surplus of heat in the smelting process.

[0003] Thermal imbalances can trigger a series of technological challenges: First, to dissipate excess heat, large amounts of coolant (such as ore or limestone) must be added, increasing material consumption and costs. Second, unbalanced process temperature control can easily lead to increased converter splashing, not only increasing steel consumption but also, in severe cases, causing splashed slag to adhere to the fume hood and charging port, accumulating in large quantities in the furnace pit, resulting in unplanned shutdowns. Finally, reduced endpoint temperature and chemical composition accuracy necessitate multiple reblowing cycles, decreasing production efficiency and increasing energy consumption and metal loss. Therefore, in the high-speed rail steel ratio model, accurately and stably controlling the converter smelting thermal balance has become a key technical challenge for achieving stable, efficient, and low-cost steelmaking.

[0004] Existing static or dynamic converter models are typically designed based on a standard iron-to-steel ratio. Under high iron-to-steel ratio conditions, core parameters such as heat balance calculations, oxygen consumption predictions, and secondary lance measurement timing become ineffective, failing to provide accurate guidance for operators. Operators rely primarily on experience to adjust the coolant dosage, which introduces significant randomness and makes precise process control difficult. Summary of the Invention

[0005] This invention aims to solve the aforementioned problems in the prior art by providing a production method and control system for precisely controlling thermal balance under high-speed rail steel ratio conditions. This method systematically addresses the problem of excess heat caused by high-speed rail steel ratios. By precisely controlling the addition of various iron-containing secondary resources (cold materials), excess heat is absorbed, thereby stabilizing the smelting process, reducing splashing, improving endpoint hit rate, and achieving resource recovery and cost reduction.

[0006] To solve the above-mentioned technical problems, the present invention provides a production method for accurately controlling thermal balance under the high-speed rail steel ratio mode, comprising the following steps: S1. Based on the target iron-to-steel ratio and scrap steel ratio, determine the amount of molten iron and scrap steel to be added, establish the correspondence between the amount of molten iron and scrap steel added, and fix the proportion of scrap steel material type; S2. Calculate and determine the basic amount of lime to be added based on the silicon content of molten iron and the phosphorus content requirements of steel grade; S3. Measure and establish a database of temperature drop coefficients for various materials used in converter smelting, and update the temperature drop coefficients to the thermal effect model of the converter sub-lance control system. At the same time, adjust the oxygen consumption parameters of the model and the timing of sub-lance measurement according to the high-speed rail steel ratio mode. S4. Based on the updated secondary gun control system, dynamic heat balance control is performed using its temperature control module during the smelting process: This module calculates the static heat surplus / deficit based on the initial loading conditions, collects the feeding information during the smelting process in real time, dynamically accumulates the actual heat change based on the temperature drop coefficient, and guides the operator to accurately add iron-containing secondary resources by comparing the difference between the static heat surplus / deficit and the dynamic accumulated heat change, so as to control the temperature of the smelting process and ensure that the final temperature hits the target.

[0007] Further, in step S1, the target iron-to-steel ratio is 810-870 kg / t, the scrap steel ratio is 190-240 kg / t, and the converter charge is 161-165 tons.

[0008] Further, in step S2, the formula for calculating the amount of lime added is: Lime addition amount (kg / t steel) = 2.14 × [Si%] × R × 1000 / CaO% effective Where CaO% effective = CaO% lime - R × SiO2% lime; When smelting rebar or ordinary carbon low-alloy steel, the basicity R should be controlled at 2.3-2.7. When smelting low-phosphorus steel, R should be controlled between 2.7 and 3.3.

[0009] Further, in step S3, the material includes at least several of lime, raw dolomite, limestone, magnesium spheres, particle steel, magnetic separation powder, cold-pressed spheres, and return ore; the temperature drop coefficient is determined by adding a single material alone in a test furnace without slag or splashing and measuring the end-point temperature change.

[0010] Furthermore, the temperature drop coefficients are as follows: lime 10℃ / t, raw dolomite 27℃ / t, limestone 28℃ / t, magnesium spheres 12℃ / t, particle steel 18℃ / t, magnetic separation powder 15℃ / t, cold-pressed spheres 25℃ / t, and return ore 30℃ / t.

[0011] Furthermore, the oxygen consumption parameters of the adjusted model are: the oxygen consumption per furnace is increased by 300-500 cubic meters; the timing of the auxiliary lance measurement is adjusted by: shifting the oxygen supply of the auxiliary lance temperature and carbon determination (TSC) measurement timing back by 300 cubic meters, so that the carbon content of the molten pool is between 0.20-0.35% during the measurement.

[0012] Furthermore, in step S4, the iron-containing secondary resources include one or more of magnetic separation powder, cold-pressed briquettes, recycled ore, and particle steel.

[0013] Furthermore, the temperature control module simultaneously displays the static heat surplus / deficit value, the dynamic cumulative heat change value, and the real-time difference between the two on the operation interface.

[0014] The present invention also provides a control system for precisely controlling thermal balance under the high-speed rail steel ratio mode, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the production method for precisely controlling thermal balance under the high-speed rail steel ratio mode described in steps S1-S4.

[0015] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the production method for precisely controlling thermal balance under the high-speed rail steel ratio mode described in steps S1-S4.

[0016] The present invention provides a production method and control system for precisely controlling thermal balance under high-speed rail steel ratio mode, which has the following significant advantages compared with the prior art: 1. Effectively solves the problems of splashing and consumption: Through precise heat balance control, it avoids the violent splashing caused by excess heat under high-speed rail steel ratio, thereby reducing the consumption of steel materials and flux, and eliminating production accidents such as sticking to the fume hood and blocking the feed port caused by splashing, thus ensuring continuous and stable production.

[0017] 2. Significantly improved endpoint control accuracy and production efficiency: This method stabilizes the converter smelting process, increasing the endpoint carbon and temperature coordination hit rate to over 85%. The one-time tapping rate (single tapping rate) for low-phosphorus steel reaches over 76%, and the one-time tapping rate for ordinary rebar reaches over 89%, significantly reducing the number of reblowing operations and improving production rhythm and efficiency.

[0018] 3. Achieving cost reduction and efficiency improvement: By maximizing the use of lower-cost iron-containing secondary resources (such as magnetic separation powder and cold-pressed briquettes) to absorb excess heat, some of the more expensive coolants (such as ore) are replaced, and the metallic iron is recovered. Simultaneously, the addition of raw materials such as raw dolomite replaces some lime, further reducing costs. Practice shows that applying this method can significantly reduce steelmaking material consumption, with lime consumption reduced to approximately 30.09 kg / t of steel. Attached Figure Description

[0019] Figure 1 A flowchart of a production method for precisely controlling thermal balance under a high-speed rail steel ratio mode, provided as an embodiment of the present invention. Detailed Implementation

[0020] See Figure 1 The present invention provides a production method for precisely controlling thermal balance under the high-speed rail steel ratio mode, comprising the following steps: S1. Based on the target iron-to-steel ratio and scrap steel ratio, determine the amount of molten iron and scrap steel to be added, establish the correspondence between the amount of molten iron and scrap steel added, and fix the proportion of scrap steel material type.

[0021] The target iron-to-steel ratio is 810-870 kg / t, the scrap steel ratio is 190-240 kg / t, and the converter charge is 161-165 tons.

[0022] S2. Calculate and determine the basic amount of lime to be added based on the silicon content of molten iron and the phosphorus content requirements of steel.

[0023] The formula for calculating the basic amount of lime added is as follows: Lime addition amount (kg / t steel) = 2.14 × [Si%] × R × 1000 / CaO% effective Where CaO% effective = CaO% lime - R × SiO2% lime; When smelting rebar or ordinary carbon low-alloy steel, the basicity R should be controlled at 2.3-2.7. When smelting low-phosphorus steel, R should be controlled between 2.7 and 3.3.

[0024] S3. Measure and establish a database of temperature drop coefficients for various materials used in converter smelting, and update the temperature drop coefficients to the thermal effect model of the converter sub-lance control system. At the same time, adjust the oxygen consumption parameters of the model and the timing of sub-lance measurement according to the high-speed rail steel ratio mode. The materials include at least several of lime, raw dolomite, limestone, magnesium balls, granulated steel, magnetic separation powder, cold-pressed balls, and return ore; the temperature drop coefficient is determined by adding a single material alone in a test furnace without slag or splashing and measuring the final temperature change.

[0025] The temperature drop coefficients are as follows: lime 10℃ / t, raw dolomite 27℃ / t, limestone 28℃ / t, magnesium spheres 12℃ / t, particle steel 18℃ / t, magnetic separation powder 15℃ / t, cold-pressed spheres 25℃ / t, and return ore 30℃ / t.

[0026] The oxygen consumption parameters of the adjustment model are as follows: the oxygen consumption per furnace is increased by 300-500 cubic meters; the timing of the auxiliary lance measurement is adjusted by shifting the oxygen supply of the auxiliary lance temperature and carbon determination (TSC) measurement timing back by 300 cubic meters, so that the carbon content of the molten pool is between 0.20-0.35% during the measurement.

[0027] S4. Based on the updated secondary gun control system, dynamic heat balance control is performed using its temperature control module during the smelting process: This module calculates the static heat surplus / deficit based on the initial loading conditions, collects the feeding information during the smelting process in real time, dynamically accumulates the actual heat change based on the temperature drop coefficient, and guides the operator to accurately add iron-containing secondary resources by comparing the difference between the static heat surplus / deficit and the dynamic accumulated heat change, so as to control the temperature of the smelting process and ensure that the final temperature hits the target.

[0028] The iron-containing secondary resources include one or more of the following: magnetic separation powder, cold-pressed briquettes, recycled ore, and particle steel.

[0029] The temperature control module simultaneously displays the static heat surplus / deficit value, the dynamic cumulative heat change value, and the real-time difference between the two on the operation interface.

[0030] Specifically, this invention provides a production method for precisely controlling thermal balance under high-speed rail steel ratio mode, which is achieved through the following four steps: S1. Determine the basic loading regime: Based on the company's iron-to-steel ratio target (e.g., 810-870 kg / t) and scrap steel ratio target (e.g., 190-240 kg / t), the fixed charge range for the converter is determined (e.g., 161-165t, target 163t). Based on this, a correspondence table between the amount of molten iron and scrap steel added is established to ensure that when the iron-to-steel ratio changes, the total charge and final temperature can be met by adjusting the amount of scrap steel. The amounts of molten iron and scrap steel added can be optimized and adjusted according to the relationship in Table 1 below.

[0031] Table 1 Relationship between the amount of molten iron and scrap steel added

[0032] At the same time, the proportion of various types of scrap steel is fixed according to the available scrap steel types. For example: 10.5t of steel pipe / Grade 1 scrap steel, 4t of shavings, 6t of heavy scrap, 2t of Grade 3 briquettes, 2.5t of slag steel, totaling 25t.

[0033] S2. Determine the amount of lime base to be added: The amount of lime to be added is determined based on the silicon (Si) content of the molten iron and the phosphorus content requirements of the steel grade being smelted. The calculation formula is as follows: Lime addition amount (kg / t steel) = 2.14 × [Si%] × R × 1000 / CaO% effective Wherein, CaO% effective = CaO% lime - R × SiO2% lime.

[0034] When smelting rebar and ordinary carbon low alloy steel, the basicity R should be controlled between 2.3 and 2.7; when smelting low phosphorus steel (P≤0.020%), the basicity R should be controlled between 2.7 and 3.3.

[0035] You can refer to Table 2 below for quick reference: Table 2 Reference Standards for Lime Addition

[0036] S3. Establish a database of material cooling effects and maintain the model: a) Fix the silo information for various fluxes (lime, raw dolomite, etc.) and secondary resources (cold-pressed briquettes, return ore, magnetic separation powder, etc.) to ensure that the physical materials correspond one-to-one with the data in the control system.

[0037] b) Determine the cooling effect (temperature drop coefficient) of various materials through experiments: In a normal smelting furnace without slag or splashing, add a single material, collect data on the final temperature, carbon content, and the amount of material added, and calculate the temperature drop (°C / t) of the molten pool caused by adding one ton of that material. The temperature drop coefficients are shown in Table 3 below: Table 3 Temperature drop coefficients for various materials

[0038] c) Update the above temperature drop coefficient data into the thermal effect model of the converter sub-lance control system, replace the old parameters, and ensure the accuracy of the model calculation.

[0039] d) Based on the increase in molten iron volume under the high-speed rail steel ratio mode (e.g., an increase of about 5t), adjust the model parameters accordingly: increase the oxygen consumption per furnace by 300-500 cubic meters, and delay the measurement timing of the secondary lance temperature and carbon determination (TSC) by about 300 cubic meters of oxygen supply, so that the carbon content of the molten pool is between 0.20-0.35% during measurement, ensuring the accuracy of the secondary lance measurement data.

[0040] S4. Achieve precise process control through the optimized and upgraded secondary gun "temperature control module": A "temperature control module" is added or optimized to the secondary gun control system. This module adds a dynamic cumulative calculation function to the existing static heat balance calculation (which calculates the initial heat gain / loss based on molten iron, scrap steel, and target temperature). 1) Real-time collection of the type and weight of materials added each time during the smelting process.

[0041] 2) Based on the accurate temperature drop coefficient of the material maintained in S3, calculate the temperature drop caused by this feeding in real time and add it to the current total heat change.

[0042] 3) Display the difference between "static calculation of heat surplus / deficit" and "dynamic cumulative heat change" in real time.

[0043] 4) Based on this difference, the operator judges the current heat status and, according to the guidance of the "temperature control module", accurately calculates the type and quantity of iron-containing secondary resources (such as magnetic separation powder, cold pressing briquette, return ore, etc.) that need to be added later, so as to control the process temperature on the ideal track and ultimately make the "thermal effect difference" approach zero, ensuring that the endpoint temperature is hit.

[0044] The following describes in further detail a production method for precisely controlling thermal balance under a high-speed rail steel ratio mode, provided by the present invention, but the scope of protection of the present invention is not limited thereto.

[0045] Example 1: Smelting furnace number 25110377, steel grade is low phosphorus steel with P≤0.020%, target final temperature 1590-1610℃. Molten iron input: 134.6t, scrap steel: 28.78t, iron-to-steel ratio: 870kg / t. Molten iron Si content: 0.31%, molten iron temperature: 1327℃. Static model calculation shows a heat surplus of 160℃.

[0046] Theoretical calculations require the addition of the following fluxes: 6435 kg of lime, 926 kg of magnesium balls, and 3029 kg of raw ore.

[0047] Actual operation: Guided by the "temperature control module", 6254 kg of lime was added, and secondary resources such as 1348 kg of magnetic separation powder, 560 kg of cold-pressed balls, and 508 kg of raw dolomite were mainly used to adjust the heat balance. In addition, 827 kg of magnesium balls and 1634 kg of raw ore were added.

[0048] Process control: The module displays that the difference in thermal effect fluctuates within a small range, eventually reaching -1℃.

[0049] Results: The smelting process was smooth and without splashing. The measured final temperature was 1596℃. The steel was successfully tapped in one go, and the final temperature and composition were both accurate.

[0050] Example 2: Smelting furnace number 25210765, steel grade is specialty steel with P≤0.015%, target final temperature 1590-1610℃. Molten iron input: 133.97t, scrap steel: 25.52t, iron-to-steel ratio: 870kg / t. Molten iron Si content: 0.25%, molten iron temperature: 1315℃. Static calculated heat surplus: 172℃.

[0051] Theoretical calculations require the addition of the following fluxes: 6897 kg of lime, 740 kg of magnesium balls, and 3155 kg of raw ore.

[0052] Actual operation: Under the guidance of the "temperature control module", 5582 kg of lime was added, along with a large amount of magnetic separation powder (2750 kg) and cold-pressed balls (560 kg) to absorb heat. Additionally, 938 kg of raw dolomite, 741 kg of magnesium balls, and 1201 kg of raw ore were added.

[0053] Process control: The thermal effect difference is -3℃.

[0054] Result: Smelting was under control, with a final temperature of 1597℃, and steel was successfully tapped in one go.

[0055] Example 3: Smelting furnace number 25210765 (another furnace), steel grade P≤0.020%, target final temperature 1590-1610℃. 135t of molten iron and 28.82t of scrap steel were fed into the furnace, with an iron-to-steel ratio of 865kg / t. The molten iron had a Si content of 0.41% and a temperature of 1290℃. The statically calculated heat surplus was as high as 246℃.

[0056] Theoretical calculations require the addition of the following fluxes: 6472 kg of lime, 695 kg of magnesium balls, and 5387 kg of raw ore.

[0057] Actual operation: Under the guidance of the module, 7285 kg of lime was added, and the heat was mainly balanced by a large amount of secondary resources such as 3193 kg of magnetic separation powder and 1442 kg of cold-pressed balls. In addition, 1071 kg of raw dolomite, 583 kg of magnesium balls and 1653 kg of raw ore were added.

[0058] Process control: The thermal effect difference is -11℃.

[0059] Result: The final temperature was 1598℃, and the steel was successfully tapped in one go.

[0060] Industrial application effects: After the method was implemented in three converters, production was stable under the high-speed rail steel ratio mode, and no major splashing accidents occurred. The endpoint hit rate remained stable at over 87%, converter splashing was significantly reduced, and steel material consumption was significantly reduced, achieving the phased goal of "breaking five and reaching four" (i.e., steel material consumption per ton of steel decreased from over 500 kg to below 500 kg), and steelmaking lime consumption was reduced to 30.09 kg / t.

[0061] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A production method for precisely controlling thermal balance under high-speed rail steel ratio mode, characterized in that, Includes the following steps: S1. Based on the target iron-to-steel ratio and scrap steel ratio, determine the amount of molten iron and scrap steel to be added, establish the correspondence between the amount of molten iron and scrap steel added, and fix the proportion of scrap steel material type; S2. Calculate and determine the basic amount of lime to be added based on the silicon content of molten iron and the phosphorus content requirements of steel grade; S3. Measure and establish a database of temperature drop coefficients for various materials used in converter smelting, and update the temperature drop coefficients to the thermal effect model of the converter sub-lance control system. At the same time, adjust the oxygen consumption parameters of the model and the timing of sub-lance measurement according to the high-speed rail steel ratio mode. S4. Based on the updated secondary gun control system, dynamic heat balance control is performed using its temperature control module during the smelting process: This module calculates the static heat surplus / deficit based on the initial loading conditions, collects the feeding information during the smelting process in real time, dynamically accumulates the actual heat change based on the temperature drop coefficient, and guides the operator to accurately add iron-containing secondary resources by comparing the difference between the static heat surplus / deficit and the dynamic accumulated heat change, so as to control the temperature of the smelting process and ensure that the final temperature hits the target.

2. The production method for precisely controlling thermal balance under the high-speed rail steel ratio mode according to claim 1, characterized in that, In step S1, the target iron-to-steel ratio is 810-870 kg / t, the scrap steel ratio is 190-240 kg / t, and the converter charge is 161-165 tons.

3. The production method for precisely controlling thermal balance under the high-speed rail steel ratio mode according to claim 1, characterized in that, In step S2, the formula for calculating the amount of lime added is: Lime addition amount (kg / t steel) = 2.14 × [Si%] × R × 1000 / CaO% effective Where CaO% effective = CaO% lime - R × SiO2% lime; When smelting rebar or ordinary carbon low-alloy steel, the basicity R should be controlled at 2.3-2.

7. When smelting low-phosphorus steel, R should be controlled between 2.7 and 3.

3.

4. The production method for precisely controlling thermal balance under the high-speed rail steel ratio mode according to claim 1, characterized in that, In step S3, the material includes at least several of lime, raw dolomite, limestone, magnesium balls, granulated steel, magnetic separation powder, cold-pressed balls, and return ore; the temperature drop coefficient is determined by adding a single material alone in a test furnace without slag or splashing and measuring the end-point temperature change.

5. The production method for precisely controlling thermal balance under the high-speed rail steel ratio mode according to claim 4, characterized in that, The temperature drop coefficients are as follows: lime 10℃ / t, raw dolomite 27℃ / t, limestone 28℃ / t, magnesium spheres 12℃ / t, particle steel 18℃ / t, magnetic separation powder 15℃ / t, cold-pressed spheres 25℃ / t, and return ore 30℃ / t.

6. The production method for precisely controlling thermal balance under the high-speed rail steel ratio mode according to claim 4, characterized in that, The oxygen consumption parameters of the adjustment model are: increase the oxygen consumption per furnace by 300-500 cubic meters; the timing of the auxiliary lance measurement is adjusted by shifting the timing of the auxiliary lance temperature and carbon determination measurement by 300 cubic meters of oxygen supply, so that the carbon content of the molten pool is between 0.20-0.35% during the measurement.

7. The production method for precisely controlling thermal balance under the high-speed rail steel ratio mode according to claim 1, characterized in that, In step S4, the iron-containing secondary resources include one or more of magnetic separation powder, cold-pressed briquettes, recycled ore, and particle steel.

8. The production method for precisely controlling thermal balance under the high-speed rail steel ratio mode according to claim 7, characterized in that, The temperature control module simultaneously displays the static heat surplus / deficit value, the dynamic cumulative heat change value, and the real-time difference between the two on the operation interface.

9. A control system for precisely controlling thermal balance under high-speed rail steel ratio mode, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the production method for precisely controlling thermal balance under the high-speed rail steel ratio mode as described in any one of claims 1-8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the production method for precisely controlling thermal balance under the high-speed rail steel ratio mode as described in any one of claims 1-8.

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