A manufacturing process for hot-rolled alloy structural steel plates

Abstract

This application relates to the field of alloy steel plate preparation technology, specifically to a preparation process for hot-rolled alloy structural steel plates. The process includes: removing impurities from molten steel using a converter, followed by refining and vacuum treatment of the molten steel; continuously casting the refined and vacuum-treated molten steel using a crystallizer to form a steel billet; heating the steel billet in a heating furnace; analyzing each monitoring data point during the continuous casting process and the billet heating process to obtain rolling state difference characteristic values ​​for each monitoring data point; adjusting the initial rolling reduction rate of the heated billet; dynamically adjusting the proportional parameters of the PID controller for each rolling data point during each rolling pass of the billet; and cooling and heat-stacking the billet after it has been rolled to the target thickness to obtain the hot-rolled alloy structural steel plate. This application aims to improve the mechanical properties of the rolled alloy structural steel plate.

Description

Technical Field

[0001] This application relates to the field of alloy steel plate preparation technology, specifically to a preparation process for hot-rolled alloy structural steel plates. Background Technology

[0002] Hot-rolled alloy structural steel plates possess advantages such as high strength, high toughness, and machinability, and are widely used in machinery manufacturing, the automotive industry, construction machinery, and petrochemicals. With the increasing demands for lightweight and reliable equipment in modern industry, the performance requirements for hot-rolled alloy structural steel plates are becoming more stringent. For example, in core components such as heavy machinery drive shafts and automotive gears, the alloy structural steel plates used need to meet specific strength grades and ensure uniform microstructure to prevent fracture failure due to stress concentration during use. Therefore, optimizing the manufacturing process of hot-rolled alloy structural steel plates and improving product quality stability are urgent problems to be solved.

[0003] In the preparation process of hot-rolled alloy structural steel plates, the process stability of continuous casting and heating has a significant impact on the subsequent rolling process and the quality of the finished product. If the tensile speed control is unstable during the continuous casting stage, it will lead to a large deviation in the billet thickness, which in turn will cause internal segregation and porosity defects. On the other hand, large temperature differences during the billet heating process may lead to differences in the degree of austenitization in different regions, as well as large differences in grain state and plasticity in different regions. Therefore, if there are unstable processing characteristics in the above processes, the billet state before rolling may be deviated, resulting in the rolling condition of a single pass not matching the actual deformation requirements, which is prone to cracks or folding defects. In the traditional rolling process, the control of the reduction ratio and the rolling process does not fully consider the deviation caused by the billet state in the preceding and actual rolling processes, resulting in large fluctuations in the mechanical properties of the rolled steel plate and an increased surface and internal defect rate. Summary of the Invention

[0004] In view of the above, it is necessary to provide a manufacturing process for hot-rolled alloy structural steel plates to solve the above problems.

[0005] One embodiment of this application provides a process for preparing hot-rolled alloy structural steel plates, the process comprising:

[0006] Impurities in the molten steel are removed by converter smelting. The molten steel is then transported to the LF furnace and refined with refining agent, lime, submerged arc slag and fluorite. After refining, vacuum treatment is performed, and ferroboron and pure calcium wire are added for further treatment. Finally, argon is blown softly.

[0007] The treated molten steel is continuously cast using a crystallizer to form a steel billet; the steel billet is then placed in a heating furnace for heating.

[0008] For each type of monitoring data collected during the continuous casting process and the billet heating process, the rolling state difference characteristic value of each type of monitoring data is obtained based on the difference characteristics between each type of monitoring data and the preset value within each sliding window, combined with the discrete characteristics of the monitoring data.

[0009] Based on the distribution characteristics of the rolling state difference characteristic values, the reduction rate of the initial rolling of the heated steel billet is adjusted. During each rolling pass of the steel billet, each type of rolling data is collected, the similarity between the rolling data is analyzed, and the adjustment coefficient of each type of rolling data is determined by combining the difference distribution characteristics between each type of rolling data and the preset value.

[0010] Based on the adjustment coefficient of each rolling data for each rolling pass, adjust the proportional parameters of the PID controller for the corresponding rolling data in the next rolling pass.

[0011] After rolling the steel billet to the target thickness through multiple rolling passes, it is cooled and stacked to obtain hot-rolled alloy structural steel plate.

[0012] The mass ratio of the added refining agent, lime, submerged arc slag and fluorite is 3.3:5:1.6:0.6~4.2:6.7:2.1:1.25.

[0013] The specific operation of adding ferroboron and pure calcium wire for treatment, followed by soft argon blowing, is as follows: add ferroboron to make the boron content between 0.0005% and 0.0080%, add 200m to 250m of pure calcium wire to refine the non-metallic inclusions, and soft argon blowing for ≥8 minutes after treatment.

[0014] The specific operation of continuous casting is as follows: a steel billet is formed at a stretching speed of 0.8~1.2m / min, and the superheat of the molten steel is controlled at 10℃~30℃.

[0015] Specifically, the process of placing the steel billet in a heating furnace for heating involves controlling the heating temperature at 1100℃~1250℃, controlling the temperature of the soaking zone at 1200℃~1260℃, having a heating coefficient of 0.9~1.2 min / mm, maintaining a temperature difference between the inside and outside of the steel billet ≤50℃, and ensuring a grain size ≥6.

[0016] The method for obtaining the rolling state difference characteristic value for each type of monitoring data includes:

[0017] For each type of monitoring data, the sliding window for each type of monitoring data is determined by detecting the maximum interval between mutation points;

[0018] For each type of monitoring data, calculate the difference between the data at all times within the sliding window and the preset value, and use the sum of all the differences as the stable deviation characteristic value within the corresponding time period of each sliding window;

[0019] Calculate the ratio of the stable deviation characteristic value to the preset value within the corresponding time period of each sliding window, and record it as the first ratio; for each type of monitoring data, obtain the proportion of the coefficient of variation of the data at all times in each sliding window to the value of the coefficient of variation of all sliding windows, and record it as the second ratio;

[0020] The first ratio and the second ratio are positively fused, and the positive fusion results of each monitoring data in all sliding windows are accumulated to obtain the rolling state difference feature value of each monitoring data.

[0021] Specifically, determining the adjustment coefficient for each type of rolling data involves:

[0022] Rolling data includes rolling pressure and rolling speed;

[0023] Based on the results of abrupt changes in rolling speed, the entire rolling process is divided into several time periods;

[0024] Obtain the similarity between rolling pressure and rolling speed in each time period; obtain the degree of dispersion of the difference between each rolling data and its preset value; perform positive fusion on the negative correlation mapping result of the similarity and the degree of dispersion, and calculate the average normalized value of the positive fusion result obtained in all time periods as the adjustment coefficient of each rolling data.

[0025] Specifically, the process of adjusting the proportional parameter of the PID controller in the next rolling pass involves: calculating the sum of the natural number 1 and the normalized value of the adjustment coefficient for each rolling data; and using the product of the initial proportional parameter of the PID controller and the sum as the proportional parameter of the PID controller in the next rolling pass for each rolling data.

[0026] The rolling of steel billets includes roughing and finishing rolling. The initial rolling temperature in the roughing stage is ≥1050℃; the initial rolling temperature in the finishing stage is 910℃~950℃, and the final rolling temperature is 840℃~860℃.

[0027] The specific operations for cooling and stacking are as follows: after rolling, the steel plate is air-cooled on a cooling bed, and the cooling rate is controlled to be ≤3℃ / s; after air cooling, it is stacked offline, and the temperature of the plate entering the stack is controlled at 280℃~350℃, and the stacking is carried out for 24~32 hours.

[0028] This application has at least the following beneficial effects:

[0029] This application proposes a manufacturing process for hot-rolled alloy structural steel plates. The production process includes converter smelting, refining, vacuum treatment, continuous casting, billet heating, and post-rolling cooling. This application uses a PLC control system to monitor and control parameters at each stage in real time. It analyzes the deviations in monitoring data at different stages during continuous casting and billet heating to identify characteristics of billet state deviations caused by the instability of continuous casting and heating before rolling. Based on the analysis results, the rolling pressure rate for the first rolling pass is adjusted. By analyzing billet state deviations, defects in the steel plate caused by deformation in the first rolling pass are prevented. Furthermore, the parameters in each rolling pass are monitored and analyzed. By fully considering the parameter changes caused by billet state deviations at different times, the control parameters in the actual rolling process are optimized and adjusted. The beneficial effect is that by combining the rolling pressure rate and rolling control with the differences in billet state, the quality differences caused by the differences in billet state during the manufacturing process are reduced, and the mechanical properties of the rolled steel plate are improved. Attached Figure Description

[0030] Figure 1 A flowchart illustrating the manufacturing process of a hot-rolled alloy structural steel plate provided in this application;

[0031] Figure 2 A flowchart illustrating the dynamic adjustment of the proportional parameters of the PID controller for each type of rolling data provided in this application. Detailed Implementation

[0032] In the description of the embodiments in this application, the words "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplary," "or," and "for example" is intended to present the relevant concepts in a specific manner.

[0033] 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 application belongs. The terminology used in this application's specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0034] It should also be noted that the terms "first" and "second" in this application and its accompanying drawings are used to distinguish similar objects, rather than to describe a specific order or sequence. The methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of protection of this application, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0035] 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 application pertains.

[0036] Example 1

[0037] Example 1 of this application proposes a manufacturing process for hot-rolled alloy structural steel plates, applied in the field of alloy steel plate manufacturing technology, to achieve automated and optimized manufacturing of hot-rolled alloy steel plates. The manufacturing process includes converter smelting, refining, vacuum treatment, continuous casting, billet heating, and post-rolling cooling. (Refer to the attached document.) Figure 1 The specific process is as follows:

[0038] S1 converter smelting

[0039] The molten steel is treated by using a converter to control its composition and remove some impurities. The composition control requirements are: carbon content ≥ 0.080%, phosphorus ≤ 0.010%, and sulfur ≤ 0.025%. Specifically, the temperature range of the ladle at the top of the furnace is controlled between 1610℃ and 1640℃. Slag-blocking technology is used to prevent slag from entering the ladle. The slag-blocking technology can use slag-blocking balls or slag-blocking cones.

[0040] S2 Refining

[0041] After being smelted in the converter, the molten steel enters the refining process. Specifically, the molten steel is transported to the LF furnace for refining, further adjusting the steel composition, desulfurizing, and purifying the steel. Refining agents, lime, submerged arc slag, and fluorite are added to the LF furnace, with a mass ratio of 3.3:5:1.6:4.2:6.7:2.1:1.25. After adding these materials, the LF furnace is energized for slag formation for 6-8 minutes to remove sulfur and other harmful elements. After slag formation, temperature is measured and samples are taken. Aluminum wire is added for deoxidation to form white slag, which is maintained in its white slag form for ≥10 minutes. This white slag is used to purify the molten steel, reduce oxygen content, and stabilize the steel composition.

[0042] S3 Vacuum Processing

[0043] After refining, vacuum treatment is performed to further improve the purity of the molten steel. Specifically, vacuum treatment is carried out using an RH vacuum degassing device, with a vacuum degree ≤133Pa, a total vacuum time ≥15 minutes, and a degassing time ≥10 minutes. This removes gases such as hydrogen and nitrogen from the molten steel, ensuring that the hydrogen content at the outlet is ≤2ppm, thus preventing hydrogen-induced cracking in the steel plates during subsequent production. After vacuum breaking, ferroboron is added to maintain a boron content between 0.0005% and 0.0080%, and 200-250m of pure calcium wire is added to refine non-metallic inclusions. After treatment, soft argon blowing is performed for ≥8 minutes. During the treatment, flow data is collected in real time by a flow sensor and transmitted to the PLC control system. The PLC control system controls the argon flow to cause slight peristalsis on the surface of the molten steel, promoting the floating of inclusions and improving the purity of the molten steel.

[0044] S4 Continuous Casting

[0045] The refined and vacuum-treated molten steel is continuously cast in a crystallizer at a stretching speed of 1.2 m / min to form a billet. Specifically, protective casting methods (such as covering the molten steel surface with protective slag) are used during continuous casting to prevent the impact zone from turning bright red and to avoid secondary oxidation of the molten steel. The superheat of the molten steel is controlled at 30℃ to ensure uniform solidification of the billet. After the continuous casting billet comes off the line, it is slowly cooled in a pit for 30 hours, with an initial temperature ≥550℃. After the slow cooling treatment, it is stacked among the cold billets, away from the hot billets and tuyeres, to eliminate stress within the billet through slow cooling and prevent defects such as network cracks. During the above process, temperature and stretching speed data are acquired in real time by temperature and speed sensors and transmitted to a PLC control system. The PLC control system ensures that the superheat, initial temperature, and billet stretching speed meet preset requirements.

[0046] S5 steel billet heating

[0047] The continuously cast steel billet is placed in a continuous furnace for heating treatment. The heating temperature is controlled at 1100℃, and the temperature of the soaking zone is controlled at 1200℃. The heating coefficient is 0.9min / mm, that is, 0.9 minutes of heating per millimeter of thickness. During the treatment process, the temperature inside and outside of the steel billet is kept uniform, that is, the temperature difference is ≤50℃. This refines and homogenizes the austenite grains, with a grain size ≥6. Temperature data is collected in real time by temperature sensors at different heating stages, and the temperature is controlled by feedback by a PLC control system to ensure that the temperature reaches the preset temperature.

[0048] S6 rolling

[0049] The rolling process employs a two-stage process, refining the grains through deformation and controlling the thickness of the steel plate. In the roughing stage, the initial rolling temperature is 1050℃, and a large reduction is used to break up the coarse grains in the cast state, with an initial reduction rate of 45%. In the finishing stage, the initial rolling temperature is 910℃, and the final rolling temperature is 840℃. Through multiple rolling passes, the steel billet is rolled to the target thickness of 10mm.

[0050] Specifically, in the roughing and finishing rolling processes, both processes involve four rolling passes. The reduction rate for each pass is set according to the overall reduction rate requirement. Generally, the reduction rate is larger in the initial rolling and gradually decreases in subsequent rolling processes.

[0051] After refining and vacuum treatment, molten steel undergoes continuous casting and billet heating before being rolled into billets. Differences in the state of the billets before rolling lead to significant variations in their properties during the subsequent rolling process, affecting the setting of the reduction rate. Furthermore, the stability of the rolling force during actual rolling affects the quality of the steel plate. Unstable changes in rolling speed affect the temperature and deformation uniformity through the deformation heat effect (the phenomenon where most of the mechanical energy of a metal material is converted into heat energy during plastic deformation, leading to an increase in temperature). This results in problems such as coarse grains, uneven microstructure, and plate shape defects, leading to decreased mechanical properties and large dimensional deviations. Unstable rolling force affects the rolled thickness and internal stress, causing uneven thickness and residual stress after rolling, as well as poor consistency in microstructure refinement.

[0052] Based on the above analysis, during the rolling process of hot-rolled alloy structural steel plates, after continuous casting and billet heat treatment, it is necessary to fully consider the differences in billet state caused by the tensile speed and temperature difference during continuous casting and billet heat treatment, as well as the variation characteristics of rolling parameters caused by the differences in billet state in different rolling passes during actual production, and then optimize and control the rolling process. The specific analysis and processing process is as follows:

[0053] (1) Due to the possible deviations in material processing at different stages of preparation and at different times, such as the large deviation in stretching speed during continuous casting and the large temperature difference during billet heating, the current state of the rolled billet will be significantly different. Therefore, the relevant data collected during the continuous casting and heating stages are arranged in chronological order as the monitoring data sequence. Since the monitoring data is collected throughout the continuous casting and billet heating process, in order to accurately analyze the state characteristic deviations caused by the deviations in continuous casting and billet heating before rolling, the mutation point detection algorithm is first used to obtain the mutation points in each monitoring data sequence, and all the data corresponding to the mutation points are sorted in chronological order of collection. The number of data between adjacent mutation points is counted. The larger the number, the more likely there is a change in the stability deviation during the preparation process over a relatively long period of time.

[0054] Furthermore, to accurately analyze the stability characteristics of materials in different regions before rolling during continuous casting and heat treatment, the maximum number of data points between adjacent abrupt change points corresponding to each monitoring data sequence is used as the size of the sliding window for deviation analysis at different time periods, and the step size of the sliding window is its corresponding window length. The difference between all data points within the sliding window and the preset value is calculated, and the sum of all the differences is used as the stable deviation characteristic value for each time period corresponding to each sliding window. It should be understood that if the stable deviation characteristic value is less than 0, and the smaller the value, the greater the possibility of significant thickness and stress concentration compared to actual production; if the stable deviation characteristic value is greater than 0, and the larger the value, the greater the possibility of cracks occurring in actual production due to excessive stretching speed and temperature difference.

[0055] Based on the above analysis, a comprehensive analysis of each parameter data at different stages is performed to calculate the rolling state difference characteristic value. Specifically: for each type of monitoring data, the ratio of the stable deviation characteristic value to the preset value within the corresponding time period of each sliding window is calculated and recorded as the first ratio; the proportion of the coefficient of variation of the data at all times within each sliding window to the value of the coefficient of variation in all sliding windows is obtained and recorded as the second ratio; the first ratio and the second ratio are positively fused, and the positive fusion results of each type of monitoring data in all sliding windows are accumulated to obtain the rolling state difference characteristic value of each type of monitoring data.

[0056] In this embodiment, the first The characteristic value of the difference in rolling state of the monitoring data is denoted as The formula is in the form of: In the formula: Indicates the first The rolling state difference characteristic value of the monitoring data; n represents the number of sliding windows for the x-th monitoring data; Indicates the first The monitoring data in the first Each sliding window corresponds to a characteristic value of the stable deviation within a given time period; Indicates the first The monitoring data in the first The coefficient of variation of all data within a sliding window; the larger the coefficient of variation, the worse the control stability during the corresponding time period. Indicates the first The sum of the coefficients of variation of all sliding windows of the monitoring data; The larger the value, the more significant the data change characteristics within the corresponding time period, the greater the possibility of causing differences in rolling state, and the greater the possibility of the overall state deviation caused by the stable deviation within the corresponding time period. Indicates the first The monitoring data is set with preset values. If the proportion of the monitoring data that exceeds the preset values ​​is too large or too small, it indicates that the state difference in the actual production and preparation stage may be greater; the larger the absolute value of the characteristic value that causes the difference in rolling state, the more significant the state difference caused by excessively fast or slow stretching and excessively large or small temperature difference.

[0057] (2) Based on the above analysis, if the billet's state before rolling differs due to fluctuations in continuous casting process parameters and stability during heating, then the initial rolling pressure ratio needs to be optimized. Subsequently, based on the adjusted pressure ratio and combined with real-time monitoring of rolling speed and rolling pressure data during rolling, the control strategy can be further optimized to ensure the stability and quality of the entire rolling process.

[0058] Specifically, based on the rolling state difference characteristic values ​​of different monitoring data collected during continuous casting and billet heating, the initial rolling pressure ratio is adjusted: the sum of the mean of the rolling state difference characteristic values ​​of all monitoring data and 1 is calculated; the obtained sum is positively integrated with the preset initial pressure ratio to obtain the adjusted initial pressure ratio.

[0059] In this embodiment, the adjusted initial downforce ratio is denoted as... Its formula is as follows: ;in, This indicates the adjusted initial downforce rate; This indicates the initial value set before the first adjustment of the pressure ratio; Indicates the first Characteristic values ​​of rolling state differences in various monitoring data; This indicates the number of types of monitoring data.

[0060] The billet is rolled based on the adjusted initial pressure ratio. During the rolling process, pressure and speed sensors monitor the data, and the collected rolling data is transmitted to the PLC control system. The time-series variation characteristics of the parameters for each rolling pass are analyzed. Specifically, since the rolling pressure and speed generally tend to change uniformly during rolling, unstable changes in rolling speed may lead to changes in rolling pressure. Therefore, for the collected rolling speed data, all rolling speed data are used as input. A mutation point monitoring algorithm is used to obtain mutation points in all rolling speed data. Based on the acquisition time corresponding to the mutation point, the duration of the entire rolling pass is divided. For each time period, the Pearson correlation coefficient between the rolling speed data and the rolling pressure data within that time period is calculated to measure the similarity between the two types of rolling data. The Pearson correlation coefficient between rolling speed and rolling pressure over a given time period is denoted as . The smaller the Pearson correlation coefficient, the more disordered the changes in rolling speed and pressure due to differences in rolling conditions within the corresponding time period.

[0061] Furthermore, for each type of rolling data collected during each rolling pass, the absolute value of the difference between each rolling data and its corresponding preset value is calculated. The standard deviation of all absolute values ​​of the differences obtained for each type of rolling data within each time period is also calculated. Rolling data in the first The standard deviation of all data in each time period is denoted as . The larger the standard deviation, the greater the dispersion of the rolling speed and pressure deviations during the corresponding control process, and the more significant the variation characteristics.

[0062] Based on the correlation and disorder characteristics of different time periods during the rolling process, the control process for different passes is analyzed to obtain the corresponding adjustment coefficients for each type of rolling data. The specific formula is as follows: ;in, Indicates the first The adjustment coefficient for the rolling reduction ratio based on the rolling data; This indicates an adjustment parameter, with a value of 0.01, to prevent the fraction from being meaningless due to a denominator of 0; This indicates the number of time periods divided; the larger the calculated adjustment coefficient, the worse the control stability is due to the difference in the state of the billet during the corresponding rolling process, and the greater the uniformity deviation during the corresponding rolling process.

[0063] (3) Based on the above analysis, in order to optimize the uniformity deviation caused by the difference in billet state during the continuous casting and billet heating preparation stages in the rolling process, it is necessary to analyze the reduction ratio set during the initial rolling and then adjust the parameters in the rolling control process of different passes. In this application, the PLC control system uses a PID controller; the relationship between adjusting the proportional parameters of the controller for the next pass based on the characteristics of each rolling process is as follows: ,in, This indicates the proportional parameters of various rolling data during the next rolling pass; This represents the normalized result of the adjustment coefficients for each type of rolling data during the rolling parameter control process; This represents the proportional parameter of the PID controller for each rolling data in the current rolling pass. It should be noted that during the initial rolling, the initial proportional parameter of the PID controller for each rolling data is determined by the decay curve method. Based on the above adjustment results, feedback adjustments are made to various rolling data in each rolling process. The normalization method used is the arctangent transform normalization method.

[0064] The flowchart for the dynamic adjustment of the proportional parameter of the PID controller for each type of rolling data is as follows: Figure 2 As shown.

[0065] It should be understood that, in order to address the potential instability in rolling speed and pressure control during each rolling pass, this instability is often related to differences in the billet's condition, which can lead to parameter fluctuations. To avoid these fluctuations causing billet quality defects, control parameters must be adjusted in a timely manner during multi-pass rolling to improve the response speed to rolling control deviations between different passes. Through such adjustments, it can be ensured that the billet ultimately reaches the expected thickness requirement during multiple rolling passes, thereby guaranteeing the stability of rolling quality.

[0066] S7 Post-rolling cooling and stacking cooling

[0067] Post-rolling cooling and stacking cooling can control the microstructure transformation of steel plates and eliminate internal stress. Specifically, after rolling, the steel plate is air-cooled on a cooling bed. The cooling rate is controlled to ≤3℃ / s by closely arranging the plates (avoiding blower airflow) to prevent the formation of hard and brittle structures (such as bainite) due to excessively rapid cooling. After air cooling, stacking cooling is performed offline. The offline entry temperature is controlled at 280℃, and stacking cooling is carried out for 24 hours. The slow cooling further eliminates internal stress and stabilizes the ratio of ferrite to pearlite microstructure.

[0068] Thus, a hot-rolled alloy structural steel plate was obtained.

[0069] Example 2

[0070] The preparation process of this embodiment is consistent with that of the hot-rolled alloy structural steel plate in Embodiment 1. The difference is that in S2, the mass ratio of refining agent, lime, submerged arc slag and fluorite added in the LF furnace is 3.3:5:1.6:0.6:6.7:2.1:1.25; in S4, the steel billet is formed at a stretching speed of 1 m / min during continuous casting, the superheat of the molten steel is controlled at 10℃, and the billet is slowly cooled in the pit for 38 hours after it is removed from the continuous casting line; in S5, the heating temperature of the steel billet is controlled at 1200℃, the temperature of the soaking zone is controlled at 1240℃, and the heating coefficient is 1.1 min / mm; in S6, the rolling process includes four rolling processes in roughing and finishing, with an initial reduction rate of 45%, an initial rolling temperature of 1100℃ in the roughing stage, an initial rolling temperature of 950℃ in the finishing stage, and a final rolling temperature of 860℃; in S7, the temperature of the billet entering the stack after rolling is controlled at 300℃, and the stacking is carried out for 28 hours.

[0071] Example 3

[0072] The preparation process of this embodiment is consistent with that of the hot-rolled alloy structural steel plate in Embodiment 1. The difference is that in S2, the mass ratio of refining agent, lime, submerged arc slag and fluorite added in the LF furnace is 3.3:5:1.6:4:6.7:2.1:1.25; in S4, the billet is formed at a stretching speed of 0.8 m / min during continuous casting, the superheat of the molten steel is controlled at 20℃, and the billet is slowly cooled in the pit for 48 hours after it is removed from the line; in S5, the heating temperature of the billet is controlled at 1250℃, the temperature of the soaking zone is controlled at 1260℃, and the heating coefficient is 1.2 min / mm; in S6, the rolling process includes 5 passes of roughing and finishing rolling, with an initial reduction rate of 50%, an initial rolling temperature of 1100℃ in the roughing stage, an initial rolling temperature of 910℃ in the finishing stage, and a final rolling temperature of 850℃; in S7, the temperature of the billet entering the stack after rolling is controlled at 350℃, and the stack cooling time is 32 hours.

[0073] The proportional coefficient adjustment method of the PID controller for each type of rolling data proposed in this application is used as an example, and the method of rolling with fixed proportional parameters is used as a comparative example. Comparative example 1 is consistent with the preparation data of example 1; comparative example 2 is consistent with the preparation data of example 2; and the comparative example is consistent with the preparation data of example 3. The mechanical property test results of the hot-rolled alloy structural steel plates obtained from the examples and comparative examples are shown in the table below:

[0074] Table 1: Test Results of Mechanical Properties of Hot-Rolled Alloy Structural Steel Plates

[0075]

[0076] In the mechanical property testing of hot-rolled alloy structural steel plates, yield strength refers to the critical stress at which the steel plate begins to undergo plastic deformation. It is the stress at the turning point where the material transitions from the elastic stage to the plastic stage, reflecting the material's ability to resist initial plastic deformation. Compressive strength, on the other hand, refers to the maximum stress that the steel plate can withstand before fracture, embodying the material's ultimate resistance to damage. For 10mm thick hot-rolled alloy structural steel plates, this application demonstrates improved yield strength and compressive strength compared to traditional production processes.

[0077] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description; sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0078] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A manufacturing process for hot-rolled alloy structural steel plates, characterized in that, The process includes: Impurities in the molten steel are removed by converter smelting. The molten steel is then transported to the LF furnace and refined with refining agent, lime, submerged arc slag and fluorite. After refining, vacuum treatment is performed, and ferroboron and pure calcium wire are added for further treatment. Finally, argon is blown softly. The treated molten steel is continuously cast using a crystallizer to form a steel billet; the steel billet is then placed in a heating furnace for heating. For each type of monitoring data collected during the continuous casting process and the billet heating process, the rolling state difference characteristic value of each type of monitoring data is obtained based on the difference characteristics between each type of monitoring data and the preset value within each sliding window, combined with the discrete characteristics of the monitoring data. Based on the distribution characteristics of the rolling state difference feature values, the initial rolling pressure ratio of the heated steel billet is adjusted. During each rolling pass of the steel billet, rolling data of each type is collected, including rolling pressure and rolling speed. Based on the abrupt change detection results of the rolling speed, the entire rolling process is divided into several time periods. The similarity between rolling pressure and rolling speed in each time period is obtained. The dispersion of the difference between each type of rolling data and its preset value is obtained. The negative correlation mapping result of the similarity and the dispersion are positively fused, and the normalized value of the average positive fusion result obtained from all time periods is used as the adjustment coefficient for each type of rolling data. Based on the adjustment coefficient of each rolling data for each rolling pass, adjust the proportional parameters of the PID controller for the corresponding rolling data in the next rolling pass. After rolling the steel billet to the target thickness through multiple rolling passes, it is cooled and stacked to obtain hot-rolled alloy structural steel plate.

2. The manufacturing process of a hot-rolled alloy structural steel plate as described in claim 1, characterized in that, The mass ratio of the added refining agent, lime, submerged arc slag and fluorite is 3.3:5:1.6:0.6~4.2:6.7:2.1:1.

25.

3. The manufacturing process of a hot-rolled alloy structural steel plate as described in claim 1, characterized in that, The specific operation of adding ferroboron and pure calcium wire for treatment, followed by soft argon blowing, is as follows: add ferroboron to make the boron content between 0.0005% and 0.0080%, add 200m to 250m of pure calcium wire to refine the non-metallic inclusions, and soft blow argon for ≥8 minutes after treatment.

4. The manufacturing process of a hot-rolled alloy structural steel plate as described in claim 1, characterized in that, The specific operation of continuous casting is as follows: a steel billet is formed at a stretching speed of 0.8~1.2m / min, and the superheat of the molten steel is controlled at 10℃~30℃.

5. The manufacturing process of a hot-rolled alloy structural steel plate as described in claim 1, characterized in that, The process of placing the steel billet in a heating furnace for heating specifically involves: controlling the heating temperature at 1100℃~1250℃, controlling the temperature of the soaking zone at 1200℃~1260℃, having a heating coefficient of 0.9~1.2 min / mm, maintaining a temperature difference between the inside and outside of the steel billet ≤50℃, and ensuring a grain size ≥6.

6. The manufacturing process of a hot-rolled alloy structural steel plate as described in claim 1, characterized in that, The rolling state difference characteristic values ​​obtained for each type of monitoring data include: For each type of monitoring data, the sliding window for each type of monitoring data is determined by detecting the maximum interval between mutation points; For each type of monitoring data, calculate the difference between the data at all times within the sliding window and the preset value, and use the sum of all the differences as the stable deviation characteristic value within the corresponding time period of each sliding window; Calculate the ratio of the stable deviation characteristic value to the preset value within the corresponding time period of each sliding window, and record it as the first ratio; for each type of monitoring data, obtain the proportion of the coefficient of variation of the data at all times in each sliding window to the value of the coefficient of variation of all sliding windows, and record it as the second ratio; The first ratio and the second ratio are positively fused, and the positive fusion results of each monitoring data in all sliding windows are accumulated to obtain the rolling state difference feature value of each monitoring data.

7. The manufacturing process of a hot-rolled alloy structural steel plate as described in claim 1, characterized in that, The process of adjusting the proportional parameter of the PID controller in the next rolling pass is specifically as follows: calculate the sum of the natural number 1 and the normalized value of the adjustment coefficient for each rolling data; and use the product of the initial proportional parameter of the PID controller and the sum as the proportional parameter of the PID controller in the next rolling pass for each rolling data.

8. The manufacturing process of a hot-rolled alloy structural steel plate as described in claim 1, characterized in that, The rolling of steel billets includes roughing and finishing rolling. The initial rolling temperature in the roughing stage is ≥1050℃; the initial rolling temperature in the finishing stage is 910℃~950℃, and the final rolling temperature is 840℃~860℃.

9. The manufacturing process of a hot-rolled alloy structural steel plate as described in claim 1, characterized in that, The specific operation of cooling and stacking treatment is as follows: after rolling, the steel plate is air-cooled on a cooling bed, and the cooling rate is controlled to be ≤3℃ / s; after air cooling treatment, it is stacked offline, and the temperature of the offline entry into the stack is controlled at 280℃~350℃, and the stacking is carried out for 24~32 hours.

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