A method for monitoring the process of thick slab continuous casting

Abstract

This invention belongs to the field of iron and steel metallurgical production technology and discloses a process monitoring method for thick slab continuous casting production. Targeting the forming and processing characteristics of thick slab continuous casting, the method includes: calculating the temperature field during the continuous casting solidification process, extracting key temperature data and drawing a multi-view visualization cloud map of the solidification process; calculating and visualizing the location of the two-phase region based on material solidification properties; and monitoring and issuing alarms for continuous casting process parameters. It achieves recording and tracking of the cooling process of each slab, simulating and calculating the temperature field of the slab using production process parameters, and visualizing the temperature field. Control lines are set for quality-related process parameters to identify abnormal process conditions and issue alarm prompts to technicians. This invention solves the problem that existing technologies cannot meet the requirements of solidification process visualization and process parameter monitoring and alarms. It can perform real-time calculation and visualization of the solidification process temperature field based on production process parameters, assisting technicians in monitoring the production process.

Description

Technical Field

[0001] This invention relates to the field of iron and steel metallurgical production technology, and in particular to a process monitoring method for thick slab continuous casting production. Background Technology

[0002] There is a strong demand for thick, high-strength, and high-toughness steel plates in basic infrastructure sectors such as marine engineering, shipbuilding, bridge construction, and pressure vessels. To produce plates with high strength and good impact toughness, semi-finished products 4 to 10 times thicker than the finished product are required. Due to the advantages of continuous casting, such as high production efficiency, high rolling yield, short heating time, low gas consumption, and short production cycle, the stable production of defect-free thick slabs has become the main direction of continuous casting technology development.

[0003] Due to the metallurgical characteristics of continuous casting, the quality of the continuously cast billet is directly affected by changes in the temperature field. Abnormal temperature distribution can easily lead to defects such as cracks, segregation, shrinkage cavities, and porosity, and in severe cases, production accidents such as steel leakage may occur. Currently, monitoring of the temperature field in the continuous casting process mainly relies on temperature measuring instruments to determine the surface temperature of key points and calculations using empirical formulas. However, the accuracy of these measurements is difficult to guarantee because they are affected by factors such as water vapor, iron oxide scale, and water film. Furthermore, temperature measuring instruments can only measure the surface temperature of the billet and cannot accurately monitor the internal temperature field. Monitoring of process parameters during production relies on manual labor, failing to achieve automated anomaly detection and alarm systems.

[0004] In recent years, with the development of information technology, digital visualization and anomaly detection technologies have become important means to solve this problem, providing technical conditions for monitoring the continuous casting production process. Currently available technologies include: a method for visualizing the three-dimensional temperature field of continuous casting that supports multiple billet molds (application number 202210553033.3). Its advantage lies in its ability to establish a three-dimensional model based on the billet mold and visualize the temperature field through rendering based on temperature data. However, its drawback is that it relies on existing temperature field data, and establishing the three-dimensional model and rendering consume significant computational resources, affecting the model's real-time performance. Summary of the Invention

[0005] In view of the above problems, the present invention provides a process monitoring method for thick slab continuous casting production, which is used to monitor the solidification process and process parameters in the continuous casting production process. The purpose is to solve the problem that the existing continuous casting monitoring system cannot meet the requirements of solidification process visualization, process parameter monitoring and abnormal alarm.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a process monitoring method for thick slab continuous casting production, which is divided into a data acquisition and management stage, a continuous casting temperature field visualization stage, and an operation technology data monitoring stage.

[0007] The data acquisition and management phase is implemented by the continuous casting computer system and the continuous casting production data governance platform. The continuous casting computer system acquires and manages equipment record data and automated acquisition data during the production process. The continuous casting production data governance platform performs multi-source data matching and alignment on the equipment record data and automated acquisition data, and performs data conversion, data cleaning and data matching to obtain composition-process data.

[0008] The continuous casting temperature field visualization stage includes cooling zone division, billet cooling process calculation, cooling boundary condition correction, continuous casting temperature field solution and continuous casting temperature field visualization; the composition-process data are processed by each part of the continuous casting temperature field visualization stage in sequence to obtain the continuous casting process temperature field visualization result.

[0009] The aforementioned operational technical data monitoring stage includes a process parameter monitoring section and an alarm section. Control lines are set for the operational technical data processed in the data acquisition and management stage, and the processed operational technical data is monitored in real time. Data exceeding the control lines is judged to determine the billet to which it belongs, and the billet is marked as an abnormal billet or an alarm is triggered. For billets that trigger alarms, technicians intervene to analyze the fault by combining the operational technical data with the visualization results of the continuous casting temperature field.

[0010] The continuous casting production data management platform divides the casting stream into N samples along the casting direction. When the volume of the casting billet passing through the crystallizer outlet reaches 1 / N of the total sample volume, the casting billet corresponding to that volume segment is divided into a casting billet sample. For each casting billet sample, multi-source data matching and alignment are performed based on the equipment record data and automated acquisition data corresponding to the timestamp. After data conversion, data cleaning and data matching, the composition-process data of each stage of the casting billet sample are obtained, the data is stored, and the material of the casting billet sample is tracked according to the continuous casting speed.

[0011] For the composition-process data used to construct the overall solidification temperature field of continuous casting, a set of casting speed and cooling process parameter data is collected every 5 to 10 seconds to achieve a complete record of the continuous casting process parameters.

[0012] The cooling zone is specifically divided as follows:

[0013] The casting flow is divided into three cooling zones: the crystallizer, the secondary cooling zone, and the air cooling zone. In the secondary cooling zone, along the casting flow direction, the zone is divided into multiple cooling segments based on the cooling water circuits and the number and position of controllable opening and closing conical atomizing nozzles. The cooling water volume of each segment is calculated based on the circuit opening and closing status. The secondary cooling zone is divided into n cooling segments; the closed circuits are the air cooling segments, and the open circuits are the water cooling segments. The cooling water volume Q per unit time for each water cooling segment is calculated based on the number and position of the open conical atomizing nozzles. nLet Q be the cooling water volume Q per unit time in the cooling zone. Each cooling segment has x conical mist nozzles on its two side surfaces and y conical mist nozzles on its top and bottom surfaces. Then, the cooling water volume Q2 per unit time on the side surfaces and the top and bottom surfaces of each segment are calculated by the following formulas.

[0014]

[0015]

[0016] The cooling process calculation specifically involves: dividing the billet sample into multiple calculation units along the casting direction according to the required calculation accuracy; the cooling process of each calculation unit includes the calculation boundary cooling conditions and cooling time. The cooling process depends on the duration of each cooling segment experienced by the calculation unit during production, as well as the cooling intensity of each cooling segment; the current cooling segment of the calculation unit is determined based on the distance of the meniscus of the crystallizer and the casting speed. The cooling boundary conditions are related to the continuous casting speed v and the casting time t, satisfying the following relationship:

[0017]

[0018] In the formula, L is the distance from a certain point in the casting stream to the meniscus, in meters (m); v(t) is the continuous casting speed as a function of time t, in meters per minute (m / min); t1 is the time required for the billet to reach that point, in minutes; the entire continuous casting process is divided into several cooling intervals L. k For k∈N+, the length position corresponding to L belongs to the cooling interval L. k The cooling conditions of the computing unit correspond to the cooling conditions of the cooling zone.

[0019] The cooling boundary condition correction modifies the cooling boundary conditions of the cold zone segments; the cooling water volume per unit time on the lower surface of the billet is α times the cooling water volume per unit time on the upper surface of the billet, where α is the cooling water loss coefficient; the corrected water flow density W on the upper surface of the billet. 上 With the water flow density W at the lower surface 下 The relationship between them is calculated using the following formula;

[0020]

[0021] The continuous casting temperature field solution and visualization are performed as follows: For large-section thick slabs with a thickness exceeding 400 mm, after determining the thermophysical properties of the material and the cross-sectional dimensions of the slab, the cooling boundary conditions during the cooling process are determined and corrected based on the composition-process data recorded by the data acquisition and management section. For each divided calculation unit, the solidification temperature field of the slab is calculated using the finite difference method based on the continuous casting solidification heat transfer mathematical model and the corrected solidification boundary conditions. The solution results are a temperature field numerical matrix. According to the required visualization perspective, the required data is extracted from the temperature field numerical matrix, and a temperature field cloud map is drawn to achieve temperature field visualization. Based on the liquidus and solidus temperatures of the material, the location and shape of the solidified pasty region are drawn on the cross-sectional temperature field cloud map.

[0022] The continuous casting temperature field solution process uses a self-learning module, which sets up multiple temperature measurement points on the production line. Based on the temperature measurement data and calculation results, the parameters of the mathematical model for the solidification heat transfer of continuous casting in different cooling sections are corrected. Temperature measuring instruments are set up at the outlet of the continuous casting machine crystallizer, at the end of the last water cooling section of the secondary cooling zone, at the inlet of the first straightening machine, and at the flame cutting point to adjust the parameters of the mathematical model for the solidification heat transfer of continuous casting.

[0023] Based on the required visualization perspective, temperature field cross-sections perpendicular to and along the billet pulling direction are constructed to support multi-angle visualization of the internal temperature field of the billet. The required data are extracted from the calculated temperature field numerical matrix, and temperature field cloud maps are drawn based on the numerical points. Solidified pasty areas are drawn on the cross-sectional temperature field cloud maps of the unsolidified stage.

[0024] The control lines are set as follows: ±3% to ±5% control lines are set for casting speed, casting temperature, and cooling water volume per unit time in each cooling section. When the above process parameters fluctuate abnormally beyond the control line for more than 5 to 10 seconds, they are marked as abnormal casting billets. When the casting speed fluctuates beyond the control line by more than 10%, an alarm is triggered and the operator intervenes.

[0025] The beneficial effects of this invention: The process monitoring method for continuous casting of thick slabs proposed in this invention is applicable to the continuous casting of large-section thick slabs with a thickness exceeding 400mm. It can be dynamically added to the casting machine's computer system and run in parallel with the existing continuous casting production control system. By collecting and processing production data generated by the casting machine's secondary computer system, it achieves the recording and tracking of the cooling process of each slab, simulates and calculates the temperature field of the slab using production process parameters, and visualizes the temperature field. Control lines are set for quality-related process parameters to identify abnormal process conditions and issue alarm prompts to technicians. This invention solves the problem that existing technologies cannot meet the requirements of solidification process visualization, process parameter monitoring, and abnormal alarms. It can perform real-time calculation and visualization of the solidification process temperature field based on production process parameters, assisting technicians in monitoring the production process. This method requires fewer computational resources and has a fast calculation speed, meeting the needs of real-time online production control. Attached Figure Description

[0026] Figure 1 A flowchart of a process monitoring method for thick slab continuous casting production;

[0027] Figure 2 A flowchart for solving and visualizing the continuous casting temperature field;

[0028] Figure 3 This is a visualization of the continuous casting temperature field along the casting direction in Embodiment 1 of the present invention.

[0029] Figure 4 This is a visualization of the continuous casting temperature field perpendicular to the continuous casting direction in Embodiment 1 of the present invention. Detailed Implementation

[0030] The process monitoring method for thick slab continuous casting production proposed in this invention is used to realize visualization and abnormal monitoring of the solidification process in continuous casting production. It can detect production parameters in real time and visualize the internal temperature field and solidification of thick slab, assisting production technicians in monitoring abnormal situations in the continuous casting process.

[0031] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0032] A process monitoring method for continuous casting of thick slabs, targeting large-section thick slabs with a thickness exceeding 400 mm, is disclosed. The monitoring method includes a temperature field calculation component, a continuous casting process visualization component, and a process parameter monitoring and alarm component. The visual monitoring system, composed of the temperature field calculation component and the continuous casting process visualization component, together with the numerical monitoring system for the process parameter monitoring and alarm component, constitutes the entire continuous casting process monitoring system. Each component processes data from the same source in different ways to complete its respective function.

[0033] The temperature field calculation data comes from the secondary control system and is processed by the continuous casting production data management platform to achieve multi-source data matching and alignment. Combined with the casting machine structure, it realizes the precise division of the cooling zone and accurate recording of the billet cooling process. The process parameter monitoring and alarm part monitors the real-time industrial data collected in the secondary control system. By communicating with the continuous casting production data management platform, it determines the billet to which the data belongs and sets control limits for the filtered data to determine whether the billet needs to be marked as an abnormal billet or an alarm should be triggered.

[0034] The continuous casting production data governance platform collects and manages data generated during the continuous casting production process, achieving multi-source data matching and alignment. The casting stream is divided into N samples along the casting direction. When the volume of the cast billet passing through the crystallizer outlet (1 / N) reaches the sample volume, the cast billet corresponding to that sample volume is classified as a single cast billet sample. This enables the recording and tracking of the cooling process of each cast billet, which is used to construct the solidification temperature field of any cast billet and to mark casting anomalies. A set of data on casting speed and cooling intensity of each cooling section is collected every 5–10 seconds, enabling the overall recording of continuous casting process parameters and contributing to the construction of the overall solidification temperature field of continuous casting.

[0035] The process monitoring scope covers the entire process from the crystallizer to the flame cutting stage. Monitoring is not limited by production conditions and supports arbitrary drawing speeds and cooling intensities. Based on the thermophysical properties, specific cross-sectional dimensions, and cooling history of the material to be produced as the steel billet, the unsteady-state heat transfer partial differential equation is used to solve the solidification temperature field of the thick slab. The temperature field calculation includes:

[0036] (1) Cooling zone division

[0037] (2) Calculation of the cooling process of the billet

[0038] The division of cooling zones is not limited to the structure of the continuous casting machine, but is subdivided based on the controllable cooling mechanism. Specifically, for each cooling zone in the secondary cooling zone, the cooling zone is divided into n segments according to the number and position of the conical atomizing nozzles opening in the billet pulling direction. The cooling water volume per unit time (Q) for each cooling segment is... nThe unit is L / min) is 1 / n of the cooling water volume per unit time (Q, unit is L / min) of the cooling zone. Each cooling segment has x and y conical aerosol nozzles on its two side surfaces and upper and lower surfaces, respectively. The cooling water volume per unit time on the side surface (Q1, unit is L / min) and upper and lower surfaces (Q2, unit is L / min) of each segment is calculated by the following formulas.

[0039]

[0040]

[0041] The boundary conditions of the billet in the secondary cooling zone are modified. The cooling water flow rate per unit time on the lower surface of the billet is α times that on the upper surface, where α is the cooling water loss coefficient. The modified water flow density (W) on the upper surface of the billet is... 上 L / (m 2 ·s)) and the water flow density at the lower surface (W) 下 L / (m 2 The relationship between ·s) can be calculated using the following formula.

[0042]

[0043] The current cooling zone and cooling process of the billet are determined based on the distance from the meniscus of the crystallizer and the casting speed. The boundary conditions of cooling are related to the continuous casting speed v and the casting time t, and satisfy the following relationship:

[0044]

[0045] In the formula, L is the distance from a certain point in the casting stream to the meniscus, in meters (m); v(t) is the continuous casting speed as a function of time t, in meters per minute (m / min); and t1 is the time required for the billet to reach that point, in minutes (min). The entire continuous casting process is divided into several cooling intervals L. k If k∈N+, and the length position corresponding to L belongs to the cooling interval L k The cooling conditions of the billet unit correspond to the cooling conditions of the cooling zone.

[0046] The continuous casting process visualization section supports visualization of the overall temperature field of the continuous casting process and the temperature evolution process of a specific piece of steel from multiple angles. In particular, it can draw the location and shape of the solidification paste region on the cross-sectional temperature field cloud map based on the liquidus and solidus temperatures of the material.

[0047] Depending on the desired visualization perspective, temperature field cross-sections perpendicular to and along the casting direction can be constructed to support multi-angle visualization of the internal temperature field of the billet. The required data is extracted from the calculated temperature field numerical matrix, and temperature field contour maps are plotted based on the numerical points. A solidified, pasty region is then plotted on the cross-sectional temperature field contour map of the unsolidified stage, facilitating real-time monitoring of the location and morphology of the pasty region in the billet by technicians. In particular, the position of the solidification end in the casting flow can be visually observed.

[0048] The visualization process eliminates the need for building 3D models and rendering, effectively saving computing resources, improving computing speed, and meeting the needs of real-time control in online production.

[0049] The production process monitoring consists of a visualization component and a process parameter monitoring component. When abnormal cooling occurs, the problematic cooling section can be directly identified through the temperature field visualization interface, and the billet in that section is marked as an abnormal billet. Control lines of ±3% to 5% are set for process parameters such as casting speed, casting temperature, and cooling water volume per unit time for each section. When abnormal fluctuations in process parameters exceed the control lines for more than 5 to 10 seconds, the billet is marked as abnormal. When fluctuations in process parameters such as casting speed, which may lead to production accidents such as continuous casting leakage, exceed the control lines by more than 10%, an alarm function is triggered to prompt operator intervention.

[0050] Temperature measuring instruments are placed at the outlet of the continuous casting machine crystallizer, at the end of the last section of water cooling in the secondary cooling zone, at the inlet of the first straightening machine, and at the flame cutting point to adjust the solidification model parameters and ensure the accuracy of model calculations.

[0051] Example 1

[0052] This invention discloses a process monitoring method for thick slab continuous casting production, such as... Figure 1 As shown, the production data collected by the continuous casting machine's computer system undergoes data processing to extract the data on casting speed and cooling intensity of each cooling section required for temperature field calculation and visualization. The calculation and visualization processes are then performed. Real-time monitoring is conducted on data collected by various sensors that are directly related to continuous casting quality. A ±3% error range is set for casting speed and casting temperature, and a ±4.5% error range is set for process parameters such as the cooling water volume per unit time in each section. Process parameters exceeding the allowable error range for more than 6 seconds are recorded, and the resulting billet is marked as an abnormal billet. If fluctuations exceed the control line by more than 10% for more than 5 seconds, an alarm function is triggered to prompt operator intervention.

[0053] The flowchart for the temperature field calculation and continuous casting process visualization section, such as... Figure 2 As shown, it includes four steps:

[0054] 101. Determine the thermophysical properties, dimensions, and production process parameters of the material to be used to produce the steel billet, and determine the solidification boundary conditions based on the process parameters.

[0055] 102. Based on the mathematical model of heat transfer during solidification in continuous casting and the boundary conditions, the solidification temperature field of the billet is calculated using the finite difference method.

[0056] 103. Based on the required visualization perspective, extract the required data from the calculated temperature field numerical matrix, and draw a temperature field cloud map based on the numerical points.

[0057] 104. Based on the liquidus and solidus temperatures of the material, plot the location and shape of the solidified paste region on the cross-sectional temperature field cloud map.

[0058] In this embodiment, Q235 carbon structural steel is used as the specific steel grade. Based on the chemical composition of the steel, thermodynamic calculation software is used to calculate the Poisson's ratio, Young's modulus, thermal conductivity, density, specific heat capacity, and other thermophysical parameters, as well as the liquidus and solidus temperatures.

[0059] The required cross-sectional dimensions of the continuously cast billet are 1600mm × 400mm. The continuous casting machine is an arc-shaped continuous casting machine. The cooling section of the continuous casting machine is divided into a crystallizer, a foot roll area, multiple secondary cooling zones, and an air cooling zone.

[0060] The heat transfer boundary conditions of the crystallizer satisfy the following relationship:

[0061]

[0062]

[0063] In the formula, q is the heat flux density inside the crystallizer at a certain moment, with units of kW / m³. 2 ;a represents the heat flux density at the meniscus of the crystallizer, in kW / m³. 2 ;q a The average heat flux density of the crystallizer is expressed in kW / m³. 2 L c is the length of the crystallizer, in meters; v is the casting speed, in meters per minute.

[0064] The heat transfer boundary conditions in the second cooling zone satisfy the following relationship:

[0065] h = 1.57 × 10 3 ×W 0.55 (1-T w ×0.0075) / k

[0066] In the formula, h is the heat transfer coefficient, with units of kW / (m³). 2 •℃); W is the cooling water flow density, in L / (m³). 2 ·s); Tw is the cooling water temperature, in °C; k is the adjustment coefficient.

[0067] The heat transfer boundary conditions in the air-cooled zone satisfy the following relationship:

[0068] q=ε2σ[(T b +273) 4 -(T a +273) 4 ]

[0069] In the formula, ε² is the radiation coefficient, with a value of 0.8; σ is the Stefan-Boltzmann constant; T b T represents the surface temperature of the cast billet, in °C. a The ambient temperature is expressed in °C.

[0070] The continuous casting process is divided into several cooling sections according to a controllable cooling mechanism, and the cooling time of each cooling section satisfies the following relationship:

[0071]

[0072] In the formula, L i denoted as , where is the length of the i-th cooling section in meters; a and b are the start and end times of the billet entering the i-th cooling section, respectively, in seconds; v(t) is the continuous casting speed as a function of time t, in m / min.

[0073] The cooling water volume per unit time for the side surface (Q1) and upper and lower surfaces (Q2) of each segment is calculated using the following formulas:

[0074]

[0075]

[0076] In the formula, n is the number of cooling segments into which the cooling zone is divided; x and y are the number of conical aerosol nozzles on the two side surfaces and the upper and lower surfaces of each cooling segment, respectively; Q is the cooling water flow rate per unit time in the cooling zone, in L / min.

[0077] The calculation of cooling water flow density on the upper and lower surfaces of the slab is corrected using the following formula:

[0078]

[0079] In the formula, α is the cooling water loss coefficient; W 上 and W 下 These are the water flow densities at the upper and lower surfaces, respectively, in L / (m²). 2 ·s).

[0080] Based on the mathematical model of heat transfer in continuous casting solidification, the differential equations are replaced with a system of linear equations using the finite difference method. In this embodiment, the explicit finite difference method is used to divide the solution domain, thereby discretizing the equations. Then, the interpolation method is used to obtain an approximate solution for the entire domain of the boundary value problem from the discrete solution.

[0081] The cooling conditions of the billet unit in different cooling zones can be described by formulas.

[0082] The cooling boundary conditions of the billet in the crystallizer section can be described by the following formula, where x and y are the width and thickness directions of the billet, respectively:

[0083]

[0084] In the formula, T is the temperature, in °C; λ is the thermal conductivity, in W / (m·K); q m (t) represents the heat flux per unit time, with units of W / m². 2 .

[0085] The cooling boundary conditions of the billet in the secondary cooling zone can be described by the following formula:

[0086]

[0087] In the formula, T b T represents the surface temperature of the cast billet, in °C. w The temperature of the cooling water is ℃; h is the overall heat transfer coefficient between the billet and the cooling water, in W / (m³). 2 ·℃).

[0088] The cooling boundary conditions of the billet in the air-cooled section can be described by the following formula:

[0089]

[0090] In the formula, ε is the radiation coefficient; σ is the Stefan-Boltzmann constant; T b T represents the surface temperature of the cast billet, in °C. a The ambient temperature is expressed in °C.

[0091] During continuous casting production, it is necessary to monitor the solidification endpoint and billet shell thickness along the entire casting flow. The calculated solidification temperature field data is extracted, and a cross-sectional view of the continuous casting billet temperature field along the casting direction is plotted, such as... Figure 3 As shown, based on the liquidus and solidus temperatures of the material, the location and shape of the solidified paste region are plotted on the cross-sectional temperature field cloud map.

[0092] Furthermore, if it is necessary to observe the temperature field of a specific cooling section during the production process, a temperature field contour map of the continuously cast billet can be drawn along the direction perpendicular to the continuous casting direction, such as... Figure 4 As shown.

Claims

1. A method of monitoring a process of continuous casting of a slab, characterized by, It is divided into three stages: data acquisition and management, continuous casting temperature field visualization, and operation technology data monitoring. The data acquisition and management phase is implemented by the continuous casting computer system and the continuous casting production data governance platform; The continuous casting computer system collects and manages equipment record data and automated acquisition data during the production process. The continuous casting production data governance platform performs multi-source data matching and alignment on the equipment record data and automated acquisition data, and performs data transformation, data cleaning and data matching to obtain composition-process data. The continuous casting temperature field visualization stage includes cooling zone division, billet cooling process calculation, cooling boundary condition correction, continuous casting temperature field solution and continuous casting temperature field visualization; the composition-process data are processed by each part of the continuous casting temperature field visualization stage in sequence to obtain the continuous casting process temperature field visualization result. The aforementioned operational technology data monitoring stage includes a process parameter monitoring section and an alarm section. Control lines are set for the operational technology data processed in the data acquisition and management stage, and the processed operational technology data is monitored in real time. Data exceeding the control lines is judged to determine the billet to which it belongs, and the billet is marked as an abnormal billet or an alarm is triggered. For the billet that triggered the alarm, technicians intervened to analyze the fault by combining operational technical data with the visualization results of the continuous casting temperature field. The cooling zone is specifically divided as follows: The casting flow is divided into three cooling zones: the crystallizer, the secondary cooling zone, and the air cooling zone. In the secondary cooling zone, along the casting flow direction, the zone is divided into multiple cooling segments based on the cooling water circuits and the number and position of controllable opening and closing conical atomizing nozzles. The cooling water volume of each segment is calculated based on the circuit opening and closing status. The secondary cooling zone is divided into n cooling segments; the closed circuits are the air cooling segments, and the open circuits are the water cooling segments. The cooling water volume Q per unit time for each water cooling segment is calculated based on the number and position of the open conical atomizing nozzles. n Let Q be the cooling water volume Q per unit time in the cooling zone. Each cooling segment has x conical mist nozzles on its two side surfaces and y conical mist nozzles on its top and bottom surfaces. Then, the cooling water volume Q2 per unit time on the side surfaces and the top and bottom surfaces of each segment are calculated by the following formulas. The cooling process calculation specifically involves: dividing the billet sample into multiple calculation units along the casting direction according to the required calculation accuracy; the cooling process of each calculation unit includes the calculation boundary cooling conditions and cooling time. The cooling process depends on the duration of each cooling segment experienced by the calculation unit during production, as well as the cooling intensity of each cooling segment; the current cooling segment of the calculation unit is determined based on the distance of the meniscus of the crystallizer and the casting speed. The cooling boundary conditions are related to the continuous casting speed v and the casting time t, satisfying the following relationship: In the formula, L is the distance from a certain point in the casting stream to the meniscus, in meters (m); v(t) is the continuous casting speed as a function of time t, in meters per minute (m / min); t1 is the time required for the billet to reach that point, in minutes; the entire continuous casting process is divided into several cooling intervals L. k For k∈N+, the length position corresponding to L belongs to the cooling interval L. k The cooling conditions of the computing unit correspond to the cooling conditions of the cooling zone.

2. The process monitoring method of thick slab continuous casting production according to claim 1, characterized by, The continuous casting production data management platform divides the casting stream into N samples along the casting direction. When the volume of the casting billet passing through the crystallizer outlet reaches 1 / N of the total sample volume, the casting billet corresponding to that volume segment is divided into a casting billet sample. For each casting billet sample, multi-source data matching and alignment are performed based on the equipment record data and automated acquisition data corresponding to the timestamp. After data conversion, data cleaning and data matching, the composition-process data of each stage of the casting billet sample are obtained, the data is stored, and the material of the casting billet sample is tracked according to the continuous casting speed. For the composition-process data used to construct the overall solidification temperature field of continuous casting, a set of casting speed and cooling process parameter data is collected every 5~10 s to achieve a complete record of the continuous casting process parameters.

3. The process monitoring method of thick slab continuous casting production according to claim 1, characterized by, The cooling boundary condition correction modifies the cooling boundary conditions of the cold zone segment; the cooling water volume per unit time on the lower surface of the billet is α times the cooling water volume per unit time on the upper surface of the billet, where α is the cooling water loss coefficient. The relationship between the modified upper surface flow density W 上 and the lower surface flow density W 下 is calculated by the following equation; 。 4. The process monitoring method of thick slab continuous casting production according to claim 1, characterized by, The continuous casting temperature field solution and visualization are performed as follows: For large-section thick slabs with a thickness exceeding 400 mm, after determining the thermophysical properties of the material and the cross-sectional dimensions of the slab, the cooling boundary conditions during the cooling process are determined and corrected based on the composition-process data recorded by the data acquisition and management section. For each divided calculation unit, the solidification temperature field of the slab is calculated using the finite difference method based on the continuous casting solidification heat transfer mathematical model and the corrected solidification boundary conditions. The solution results are a temperature field numerical matrix. According to the required visualization perspective, the required data are extracted from the temperature field numerical matrix, and a temperature field cloud map is drawn to achieve temperature field visualization. Based on the liquidus and solidus temperatures of the material, the location and shape of the solidified pasty region are drawn on the cross-sectional temperature field cloud map.

5. The process monitoring method of thick slab continuous casting production according to claim 4, characterized by, The continuous casting temperature field solution process uses a self-learning module, which sets up multiple temperature measurement points on the production line. Based on the temperature measurement data and calculation results, the parameters of the mathematical model for the solidification heat transfer of continuous casting in different cooling sections are corrected. Temperature measuring instruments are set up at the outlet of the continuous casting machine crystallizer, at the end of the last water cooling section of the secondary cooling zone, at the inlet of the first straightening machine, and at the flame cutting point to adjust the parameters of the mathematical model for the solidification heat transfer of continuous casting.

6. The process monitoring method of thick slab continuous casting production according to claim 5, characterized by, Based on the required visualization perspective, temperature field cross-sections perpendicular to and along the billet pulling direction are constructed to support multi-angle visualization of the internal temperature field of the billet. The required data are extracted from the calculated temperature field numerical matrix, and temperature field cloud maps are drawn based on the numerical points. Solidified pasty areas are drawn on the cross-sectional temperature field cloud maps of the unsolidified stage.

7. The process monitoring method for thick slab continuous casting production according to claim 1, characterized in that, The control lines are set as follows: ±3% to ±5% control lines are set for casting speed, casting temperature, and cooling water volume per unit time in each cooling section. When the above process parameters fluctuate abnormally beyond the control line for more than 5 to 10 seconds, they are marked as abnormal casting billets. When the casting speed fluctuates beyond the control line by more than 10%, an alarm is triggered and the operator intervenes.

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