A method for optimal hot delivery and hot loading of continuous casting billets based on cyber-physical system

Abstract

The present invention relates to a method for preferentially hot-delivering and hot-charging continuous casting billets based on a cyber-physical system. A cyber-physical system for the hot-delivering and hot-charging process of continuous casting billets is constructed. Based on this system, physical and virtual mapping of the hot-delivering and hot-charging process is achieved, and real-time simulation calculation of the temperature field of the continuous casting billets is completed. The continuous casting billets for charging are preferentially selected based on the simulated continuous casting billet temperature and rolling plan. The present invention solves the problems of physical and information correspondence for hot-charged continuous casting billets, difficulty in billet temperature measurement, and large temperature fluctuations of hot-charged continuous casting billets. This method enables rational charging of hot-charged continuous casting billets based on preferential selection, ensures a smooth hot-charging process, reduces changes in the furnace operation process caused by large temperature deviations of hot-charged continuous casting billets, improves hot-charging efficiency, and reduces energy consumption.

Description

Technical Field

[0001] The invention relates to a method for preferential hot delivery and hot loading of continuous casting billets based on an information-physical system, and belongs to the technical field of metallurgical automatic control. Background Art

[0002] Hot charging and hot delivery technology involves cutting and transporting the continuous casting billets produced during steelmaking and continuous casting via roller conveyors to the heating furnaces in the rolling mill. The billets can then be directly charged into the furnaces, or stacked and slowly cooled, with the hot billets cooled to a certain temperature range before being loaded into the heating furnaces. This technology is widely used across steel companies because it reduces fuel consumption, energy consumption, emissions, and costs.

[0003] Hot charging of continuous casting slabs includes direct hot charge rolling (DHCR). Direct hot charge rolling (DHCR) refers to a production process in which continuous casting slabs are not taken off the production line after cutting, but are directly transported into the hot rolling furnace for heating and rolling through rollers. Taking into account the steel rolling production plan, the same steel grade and specification are rolled according to one planned unit. The production speed of continuous casting slabs in the direct hot charge process cannot meet the furnace-out speed of continuous casting slabs in steel rolling production. Indirect hot charge rolling of continuous casting slabs by stacking and slow cooling is required in the direct hot charge process of continuous casting slabs. Therefore, hot charging of continuous casting slabs also includes indirect hot charge rolling (HCR). Indirect hot charge rolling (HCR) refers to a production process in which continuous casting slabs are taken off the production line, stacked or stored in a slow cooling pit after they are produced, and then enter the heating furnace for heating and rolling after the temperature measured before the slabs enter the heating furnace reaches the required temperature within the specified time or before they enter the heating furnace.

[0004] However, for the direct hot charging and indirect hot charging technologies, there is a lack of measurement of the temperature of the slabs during implementation, and it is impossible to achieve a reasonable selection of direct hot charging and indirect hot charging continuous casting slabs, resulting in large differences in the temperature of the hot-charged slabs entering the furnace, affecting the furnace operation process and gas consumption of the heating furnace, and thus affecting the production rhythm; for some hot-charged continuous casting slabs that require control of the furnace temperature, the stacking position of the slabs is uncertain and the temperature cannot be measured in real time, requiring operators to go to the site for confirmation. The slab warehouse environment is harsh and there are safety risks.

[0005] Therefore, it is urgent to design a hot delivery and hot charging process for continuous casting billets to solve the complexity and uncertainty problems in the hot charging and hot delivery production process. Summary of the Invention

[0006] The present invention provides a method for preferentially hot-delivering and hot-charging continuous casting billets based on an information-physical system, which solves the problems of correspondence between the physical object and information of hot-charged continuous casting billets, difficulty in measuring billet temperature, and large temperature fluctuations of hot-charged continuous casting billets. It realizes the reasonable charging of preferentially hot-charged continuous casting billets, ensures the smooth progress of the hot charging process, reduces the changes in the furnace operation process caused by large temperature deviations of hot-charged continuous casting billets, improves the hot charging efficiency, and reduces energy consumption.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A method for preferential hot delivery and hot charging of continuous casting billets based on a cyber-physical system, specifically comprising the following steps:

[0009] Step S1: constructing a cyber-physical system for the hot delivery and hot charging process of continuous casting billets, wherein the data sources of the cyber-physical system are obtained from the continuous casting machine process control system, the continuous casting basic automation system, the heating furnace process control system, the heating furnace basic automation system, the rolling mill process control system, the rolling mill basic automation system, and the manufacturing execution system;

[0010] Step S2: establishing a physical model of the continuous casting billet hot delivery and hot charging process, wherein the physical model includes a continuous casting machine, a heating furnace, a rolling mill, a roller table, a cutting device, a deburring machine, a stacking table, a slow cooling stacking position, a testing device, and the continuous casting billet;

[0011] Step S3: The cyber-physical system realizes information interaction with the physical model through the industrial Internet, where the information used for interaction includes continuous casting plan of the continuous casting machine, continuous casting production information of the continuous casting machine, rolling plan, rolling information of the rolling mill, heating furnace loading and unloading information, continuous casting billet information in the heating furnace, continuous casting billet information on the roller table, stacked continuous casting billet information, production process requirements and standard information;

[0012] Step S4: Based on the information exchanged in step S3, the dynamic position of the continuous casting billet is mapped to the cyber-physical system. The dynamic position includes the actual transportation process and position of the continuous casting billet from the continuous casting machine to the heating furnace during the hot delivery and hot charging process, forming a mapping between the virtual continuous casting billet and the actual continuous casting billet;

[0013] Step S5: Based on the information exchanged in step S3, a real-time two-dimensional temperature field model of the continuous casting billet is established to simulate the temperature field of the continuous casting billet from the continuous casting machine to the heating furnace, and the temperature field of the continuous casting billet at each stage of the hot delivery and hot charging process is calculated in real time;

[0014] The temperature field of the continuous casting billet at each stage is obtained by establishing a heat transfer model for the continuous casting billet during roller conveyance and a heat transfer model for the continuous casting billet during stacking and air cooling at the slow cooling stacking position.

[0015] Step S6: Based on step S5, the calculated continuous casting billet temperature is compared with the furnace entry temperature required by the production process, and the optimal continuous casting billet for entering the furnace is determined based on the comparison deviation and the preset allowable deviation;

[0016] Furthermore, the hot delivery and hot charging process of the continuous casting slab includes the following steps:

[0017] Step S11: starting the continuous casting machine to produce and cut the continuous casting billet;

[0018] Step S12: performing finishing operations on the continuous casting billet;

[0019] Step S13: transporting the finished continuous casting billet to roller conveyor section 1 for transport. If the continuous casting billet is directly hot-rolled, proceed to step S15; if the continuous casting billet is not directly hot-rolled, proceed to step S14;

[0020] Step S14: The continuous casting slab is transported to the stacking platform, hoisted off the production line, and stacked for cooling. After cooling to a preset temperature, the continuous casting slab is hoisted back on the production line and transported to the stacking platform again.

[0021] Step S15: transporting the continuous casting slab to roller conveyor section 2 for transportation;

[0022] Step S16: The continuous casting billet is transported by the roller conveyor in section 2 to the roller conveyor in front of the heating furnace, and then transported to the heating furnace, completing the hot delivery and hot charging process of the continuous casting billet;

[0023] Furthermore, the continuous casting machine process control system determines the continuous casting plan of the continuous casting machine, including information of the billet currently being produced and a plan of the billet to be produced, specifically including billet size data, chemical composition of the billet, and slab number of the billet;

[0024] The continuous casting basic automation system is used for real-time tracking of continuous casting billet positions and collection of on-site detection signals;

[0025] The heating furnace process control system calculates the heating rate based on the billet's entry temperature and time; and calculates the temperature field in the furnace based on the time in the furnace and the heating time and temperature of each section in the furnace.

[0026] The heating furnace basic automation system is used to control the temperature detection, heat detection information and position tracking of roller conveyor section 1, roller conveyor section 2 and the roller conveyor in front of the heating furnace;

[0027] The rolling mill process control system is used to transmit the rolling plan to the heating furnace. The rolling plan contains the rolling information of the rolling mill, including the steel type plan to be loaded into the furnace and the number of rolling blocks;

[0028] The basic automation system of the rolling mill controls the transition between the furnace roller table and the mill roller table, and also controls the motor and hydraulic systems during the rolling process.

[0029] The manufacturing execution system monitors all information during the hot delivery and hot charging of continuous casting billets in real time, including smelting plan, continuous casting plan, rolling mill plan, billet size information, steel grade information, chemical composition information, billet storage, outbound storage and location information within the warehouse;

[0030] Furthermore, a real-time two-dimensional temperature field model of the continuous casting billet is established based on the continuous casting billet information and detection instrument information stored in the cyber-physical system;

[0031] Furthermore, establishing a heat transfer model for continuous casting slabs during roller transport specifically includes the following steps:

[0032] Step S511, considering the heat transfer of the continuous casting billet in the thickness and width directions, a two-dimensional coordinate system is established with the center of the continuous casting billet as the origin, the width direction as the x-axis, and the thickness direction as the y-axis, that is, the heat transfer of the continuous casting billet is simplified to two-dimensional heat transfer;

[0033] Step S512, simplifying the heat transfer between the upper and lower surfaces of the continuous casting billet, and the heat transfer between the continuous casting billet surface and the environment is carried out in two ways: radiation and convection;

[0034] Step S513, establishing the control equation of the heat transfer model of the continuous casting billet during roller transportation:

[0035]

[0036] In formula (1), ρ is the density of the continuous casting billet, in kg / m 3 ; C p is the specific heat capacity of the continuous casting billet, in J / (Kg·K); λ is the thermal conductivity of the continuous casting billet, in W / (m·K); T is the temperature of the continuous casting billet, in K; t is the unit time, in s; x is the coordinate in the width direction of the continuous casting billet, y is the coordinate in the thickness direction of the continuous casting billet, in m;

[0037] Step S514, use explicit difference equation to solve formula (1) and obtain

[0038]

[0039] In formula (2), represents the temperature of node (i, j) at time k+1; represents the temperature of node (i, j) at time k; represents the temperature of node (i+1,j) at time k; represents the temperature of node (i-1, j) at time k; represents the temperature of node (i, j+1) at time k; represents the temperature of the node (i, j-1) at time k; Δt is the time step, Δx is the spatial step in the width direction of the continuous casting billet, and Δy is the spatial step in the thickness direction of the continuous casting billet;

[0040] Step S515: Set the initial conditions and boundary conditions of formula (2). The initial conditions are:

[0041] T(x,y,t)| t＝0 =T cut (x,y) (3);

[0042] The boundary conditions are:

[0043]

[0044] In formulas (3), (4) and (5), T cut is the temperature of the continuous casting billet when cutting is completed; ε is the blackness of the continuous casting billet; σ is the Stefan-Boltzmann constant, which is 5.67×10 -8 , unit is m 2 ·K 4 ; T is the continuous casting billet temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient;

[0045] Step S516, obtain the temperature T of the hot steel entering the furnace Infuri ,i=1,2,3…;

[0046] Furthermore, establishing a heat transfer model for the continuous casting slab during the stacking air cooling process at the slow cooling stacking position specifically includes the following steps:

[0047] Step S521: simplify the stack of continuous casting billets into a whole, and number the continuous casting billets from the top to the bottom of the whole, 1, 2, 3...

[0048] Step S522: Establish the control equation of the heat transfer model of the continuous casting billet during the stacking air cooling process:

[0049]

[0050] In formula (1), ρ g is the density of continuous casting billet, in kg / m 3 ; C gp is the specific heat capacity of the continuous casting billet, the unit is J / (Kg·K); λ g is the thermal conductivity of the continuous casting billet, in W / (m·K); T g is the temperature of the continuous casting billet, in K; t is the unit time, in s; x is the coordinate in the width direction of the continuous casting billet, y is the coordinate in the thickness direction of the continuous casting billet, in m;

[0051] Step S523, use explicit difference equation to solve formula (1) and obtain

[0052]

[0053] In formula (2), represents the temperature of node (i, j) at time k+1; Indicates the temperature of node (i, j) at time K; represents the temperature of node (i+1,j) at time k; represents the temperature of node (i-1, j) at time k; represents the temperature of node (i, j+1) at time k; represents the temperature of the node (i, j-1) at time k; Δt is the time step, Δx is the spatial step in the width direction of the continuous casting billet, and Δy is the spatial step in the thickness direction of the continuous casting billet;

[0054] Step S524, setting the boundary conditions of formula (7), respectively:

[0055] The governing equations for ground heat transfer,

[0056] The governing equations for the side of the continuous casting billet are:

[0057] The surface control equation of the continuous casting billet numbered 1 is:

[0058] The surface control equation of the continuous casting billet numbered i, T g =T c , where T c is the solution for the semi-infinitely thick formation, i.e.

[0059] In formulas (8)-(12), ε is the blackness of the continuous casting billet; σ is the Stefan-Boltzmann constant, which is 5.67×10 -8 , unit is m 2 ·K 4 ; T is the continuous casting billet temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient;

[0060] Step S525, obtain the temperature T of the hot-delivered steel at time k Nj,k ,j=1,2,3…,k=1,2,3…,N j Indicates continuous casting billet;

[0061] Furthermore, based on the production process requirements, the hot delivery steel grades S1, S2, S3…S i The furnace temperature is TInfur1 、T Infur2 、T Infur3 …T Infuri ; Determine the hot delivery steel grade S i Continuous casting billet N j Temperature T at time k Nj,k ;

[0062] Set the time when the continuous casting billet is cut as the initial starting time t0, and complete the temperature calculation of the continuous casting billet every interval Δt. The deviation between the temperature at time k and the temperature entering the furnace is: Δ Nj,k =|T Nj,k -T Infuri |;

[0063] Δ Nj,k The preset allowable deviation δ i Compare and satisfy Δ Nj,k <δ i Continuous casting billet N j For hot-feed steel grade S i Optimal continuous casting billet for furnace entry.

[0064] Through the above technical solution, compared with the existing technology, the present invention has the following beneficial effects:

[0065] 1. The cyber-physical system-based method for optimal hot delivery and hot charging of continuous casting slabs provided by the present invention integrates cyber systems and physical entities into a unified whole, realizing information perception, dynamic regulation, and information integration of the steel manufacturing process system. Through the mutual mapping, timely interaction, and efficient collaboration between cyber and physical spaces, it achieves a combination of virtual and real, information interaction, breaks the interface barrier between the continuous casting process and the hot rolling process in the hot delivery and hot charging of continuous casting slabs, and solves the complexity and uncertainty problems in the hot charging and hot delivery production process.

[0066] 2. The cyber-physical system-based method for preferential hot delivery and hot charging of continuous casting slabs provided by the present invention establishes a real-time two-dimensional temperature field model of the continuous casting slabs during transportation and stacking based on the continuous casting slab information and detection instrument information stored in the cyber-physical system. This model can simulate the temperature field of the continuous casting slabs from the continuous casting machine to the furnace, thereby achieving the purpose of real-time calculation of the temperature field of each stage of continuous casting slab transportation and stacking, thereby improving the accuracy of the calculation results.

[0067] 3. The present invention provides a method for preferential hot delivery and hot charging of continuous casting billets based on an information-physical system, which solves the correspondence between the physical objects and information of the continuous casting billets during the hot charging process, and enables the optional hot charging of continuous casting billets into the furnace according to the temperature required by the process, thereby ensuring the smooth progress of the hot charging process, reducing the changes in the furnace operation process and product quality problems caused by the temperature of the hot charged continuous casting billets, improving the hot charging efficiency, and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The present invention will be further described below with reference to the accompanying drawings and examples.

[0069] Figure 1 This is a schematic diagram of the hot delivery and hot loading process of the continuous casting slab provided by the present invention;

[0070] Figure 2 This is a schematic diagram of the network structure of the cyber-physical system provided by the present invention;

[0071] Figure 3 This is a schematic diagram of a two-dimensional coordinate system established when simplifying the heat transfer of the continuous casting slab into two-dimensional heat transfer provided by the present invention;

[0072] Figure 4 It is a schematic diagram of the present invention for obtaining the temperature field of the continuous casting billet at each stage after the continuous casting billet is divided into grids. DETAILED DESCRIPTION

[0073] The present invention will now be described in further detail with reference to the accompanying drawings.

[0074] As described in the background technology, whether it is direct hot charge rolling (DHCR) or indirect hot charge rolling (HCR), the continuous casting billet is transported by rollers or hoisted to the transport rollers in front of the heating furnace for loading into the furnace. Some production lines have temperature measuring devices in front of the furnace to measure the temperature entering the furnace. At this time, the continuous casting billet is on the rollers. Regardless of whether the temperature of the continuous casting billet meets the process requirements, it needs to be put into the furnace to avoid steel blockage. Therefore, the temperature of the slab is not measured during direct hot charging and indirect hot charging, and it is impossible to achieve a reasonable selection of direct hot charging and indirect hot charging continuous casting billets, resulting in a large difference in the temperature of the hot-charged continuous casting billets, which affects the furnace operation process and gas consumption of the heating furnace; for some hot-charged continuous casting billets that require control of the temperature entering the furnace, the stacking position of the continuous casting billet is uncertain and the temperature cannot be measured in real time. The operator needs to go to the site to confirm. At the same time, the temperature entering the furnace does not meet the process requirements, which can easily cause cracks and performance problems in the steel plate production process.

[0075] In order to solve the above problems, this application provides a method for hot delivery and hot charging of continuous casting billets based on cyber-physical systems. The cyber-physical systems (CPS) based on it integrate information systems and physical entities into a unified whole, and integrate data processing, data communication and dynamic control into one. It is a new generation of intelligent ecosystem with self-learning and self-growth capabilities. Before explaining the method provided by this application in detail, we first need to understand the specific steps involved in the hot delivery and hot charging process of continuous casting billets, such as Figure 1 As shown, the following steps are included:

[0076] Step S11: starting the continuous casting machine to produce and cut the continuous casting billet;

[0077] Step S12: performing finishing operations on the continuous casting billet;

[0078] Step S13: transporting the finished continuous casting billet to roller conveyor section 1 for transport. If the continuous casting billet is directly hot-rolled, proceed to step S15; if the continuous casting billet is not directly hot-rolled, proceed to step S14;

[0079] Step S14: The continuous casting slab is transported to the stacking platform, hoisted off the production line, and stacked for cooling. After cooling to a preset temperature, the continuous casting slab is hoisted back on the production line and transported to the stacking platform again.

[0080] Step S15: transporting the continuous casting slab to roller conveyor section 2 for transportation;

[0081] Step S16: The continuous casting billet is transported by the roller conveyor in section 2 to the roller conveyor in front of the heating furnace, and then transported to the heating furnace, completing the hot delivery and hot charging process of the continuous casting billet.

[0082] like Figure 2 As shown, this is the network structure diagram of the information-physical system for constructing the hot delivery and hot loading process of continuous casting billets provided by this application. From the figure, it can be seen that the data source of the entire information-physical system is obtained by the continuous casting machine process control system, the continuous casting basic automation system, the heating furnace process control system, the heating furnace basic automation system, the rolling mill process control system, the rolling mill basic automation system and the manufacturing execution system (MES).

[0083] The equipment involved in the cyber-physical system comprises a physical model of the equipment, including the continuous casting machine, heating furnace, rolling mill, roller table, cutting equipment, deburring machine, stacking platform, slow cooling stack, testing equipment, and continuous casting slabs. In particular, the key equipment, such as the continuous casting machine, heating furnace, and rolling mill, each has its own control system (including basic automation systems and process control systems). These systems are the primary source of data for the cyber-physical system mentioned above. Basic automation primarily involves PLCs (programmable logic controllers) for position control, sequence control, and flow regulation. These control actuators include motors, valves, hydraulic presses, pushers, and screw-down devices. Process control systems are based on physical metallurgical models for process control. The continuous casting machine process control system includes settings for casting speed and liquid level control. The heating furnace process control system controls the slab temperature field, heating time, and heating rate. The rolling mill process control system primarily calculates the rolling schedule, including reduction, rolling force, torque, and speed.

[0084] This application addresses the difficulty in measuring the temperature of continuous casting billets and the large temperature fluctuations of continuous casting billets during hot charging into a furnace. This approach uses a cyber-physical system to map the physical objects and information of the continuous casting billets during hot charging. This system uses the Industrial Internet to implement information interaction with the physical model. The information used for interaction includes continuous casting plans, continuous casting production information, rolling plans, rolling mill information, heating furnace loading and unloading information, continuous casting billet information within the heating furnace, continuous casting billet information on the roller table, stacked continuous casting billet information, production process requirements, and standard information.

[0085] Specifically, the continuous casting machine process control system provides information on the billet currently being produced and plans for upcoming billets, including billet dimensions, chemical composition, and slab numbers. Data used in subsequent model construction includes billet surface and internal temperature fields, slab numbers, dimensions (length, width, thickness), and chemical composition. The continuous casting basic automation system primarily tracks position in real time and collects on-site detection signals, providing position information for model construction, including starting position and time. The heating furnace process control system provides billet entry temperature and entry time, calculates heating rate, furnace time, and heating time and temperature for each furnace segment, thereby calculating the furnace temperature field. Data used in subsequent model construction includes furnace atmosphere temperature and furnace entry process standards. The heating furnace basic automation system primarily controls the front roller table, the handover between the continuous casting machine roller table and the heating furnace entry roller table, temperature detection and heat detection information, and position tracking. Key position information, including position and surface temperature during transportation, is used for model calculation and correction. The rolling mill process control system provides a rolling mill plan, which is transmitted to the reheating furnace. It also includes a plan for the steel grades to be loaded, the number of rolling blocks, and the model calculations for the rolling mill itself. The rolling mill basic automation system primarily controls the transition between the furnace and mill roller tables, and controls the motors and hydraulics during the rolling process. The manufacturing execution system primarily includes smelting plans, continuous casting plans, rolling mill plans, billet size information, steel grade information, chemical composition information, billet inbound and outbound storage, and inbound location information. This data provides strong support for building subsequent models.

[0086] After clarifying the above interactive information, the next step is to carry out optimal design, realize the dynamic position mapping of continuous casting billets on the cyber-physical system, map the actual transportation process and position of the continuous casting billets to the cyber-physical system, and form a mapping between virtual continuous casting billets and actual continuous casting billets. Specifically, after the continuous casting billets are cut to length after leaving the continuous casting machine, the surface temperature of the slabs is measured and recorded in the cyber-physical system, and then transported to the front of the heating furnace by rollers for loading, or stacked offline for slow cooling and then hoisted to the rollers in front of the heating furnace, and then transported to the front of the heating furnace for heating. It should be noted that this application Figure 1The provided logistics flow chart for hot delivery and hot charging of continuous casting slabs takes into account two modes: direct charging into the furnace after cutting or stacking and slow cooling before charging into the furnace. Therefore, during operation, the part involving roller transport is designed with roller transport section 1 and roller transport section 2.

[0087] Based on the above-mentioned interactive information (continuous casting billet information and detection instrument information stored in the cyber-physical system), a real-time two-dimensional temperature field model of the continuous casting billet is established to simulate the temperature field of the continuous casting billet from the continuous casting machine to the process of being sent into the heating furnace, and the temperature field of the continuous casting billet at each stage during the hot delivery and hot loading process is calculated in real time; among them, the temperature field of the continuous casting billet at each stage is obtained by establishing a heat transfer model of the continuous casting billet during roller transportation and a heat transfer model of the continuous casting billet during stacking and air cooling at a slow cooling stacking position.

[0088] First, the establishment of a heat transfer model for continuous casting billets during roller transport includes the following steps:

[0089] Step S511, considering the heat transfer of the continuous casting billet in the thickness and width directions, Figure 3 The schematic diagram of 1 / 2 of the continuous casting billet cross section provided is shown. With the center of the continuous casting billet as the origin, the width direction as the x-axis, and the thickness direction as the y-axis, a two-dimensional coordinate system is established, that is, the heat transfer of the continuous casting billet is simplified to two-dimensional heat transfer;

[0090] Step S512, simplifying the heat transfer between the upper and lower surfaces of the continuous casting billet, and the heat transfer between the continuous casting billet surface and the environment is carried out in two ways: radiation and convection;

[0091] Step S513, establishing the control equation of the heat transfer model of the continuous casting billet during roller transportation:

[0092]

[0093] In formula (1), ρ is the density of the continuous casting billet, in kg / m 3 ; C p is the specific heat capacity of the continuous casting billet, in J / (Kg·K); λ is the thermal conductivity of the continuous casting billet, in W / (m·K); T is the temperature of the continuous casting billet, in K; t is the unit time, in s; x is the coordinate in the width direction of the continuous casting billet, y is the coordinate in the thickness direction of the continuous casting billet, in m; In formula (1), the density of the continuous casting billet is constant, and the specific heat capacity of the continuous casting billet C is p The thermal conductivity λ of the continuous casting billet is a function of the continuous casting billet temperature T.

[0094] Step S514, use explicit difference equation to solve formula (1) and obtain

[0095]

[0096] In formula (2), represents the temperature of node (i, j) at time k+1; represents the temperature of node (i, j) at time k; represents the temperature of node (i+1,j) at time k; represents the temperature of node (i-1, j) at time k; represents the temperature of node (i, j+1) at time k; represents the temperature of the node (i, j-1) at time k; Δt is the time step, Δx is the spatial step in the width direction of the continuous casting billet, and Δy is the spatial step in the thickness direction of the continuous casting billet;

[0097] Step S515: Set the initial conditions and boundary conditions of formula (2). The initial conditions are:

[0098] T(x,y,t)| t＝0 =T cut (x,y) (3);

[0099] The boundary conditions are:

[0100]

[0101] In formulas (3), (4) and (5), T cut is the temperature of the continuous casting billet when cutting is completed; ε is the blackness of the continuous casting billet; σ is the Stefan-Boltzmann constant, which is 5.67×10 -8 , unit is m 2 ·K 4 ; T is the continuous casting billet temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient;

[0102] Step S516, obtain the temperature T of the hot steel entering the furnace Infuri ,i=1,2,3….

[0103] Next, the heat transfer model of the continuous casting billet during the stacking air cooling process at the slow cooling stacking position is established, which specifically includes the following steps:

[0104] Step S521: simplify the stack of continuous casting billets into a whole, and number the continuous casting billets from the top to the bottom of the whole, 1, 2, 3...

[0105] In step S522, the continuous casting billets are in close contact with each other and with the ground, and the contact thermal resistance is ignored. Therefore, the control equation of the continuous casting billet heat transfer model during the stacking air cooling process is established as follows:

[0106]

[0107] In formula (6), ρ g is the density of continuous casting billet, in kg / m 3 ; Cgp is the specific heat capacity of the continuous casting billet, the unit is J / (Kg·K); λ g is the thermal conductivity of the continuous casting billet, in W / (m·K); T g is the continuous casting temperature,

[0108] The unit is K; t is the unit time, the unit is s; x is the coordinate in the width direction of the continuous casting billet, y is the coordinate in the thickness direction of the continuous casting billet, the unit is m;

[0109] Step S523, use explicit difference equation to solve formula (1) and obtain

[0110]

[0111] In formula (7), represents the temperature of node (i, j) at time k+1; Indicates the temperature of node (i, j) at time K; represents the temperature of node (i+1,j) at time k; represents the temperature of node (i-1, j) at time k; represents the temperature of node (i, j+1) at time k; represents the temperature of the node (i, j-1) at time k; Δt is the time step, Δx is the spatial step in the width direction of the continuous casting billet, and Δy is the spatial step in the thickness direction of the continuous casting billet;

[0112] Step S524, setting the boundary conditions of formula (7), respectively:

[0113] The governing equations for ground heat transfer,

[0114] The governing equations for the side of the continuous casting billet are:

[0115] The surface control equation of the continuous casting billet numbered 1 is:

[0116] The surface control equation of the continuous casting billet numbered i, T g =T c , where T c is the solution for the semi-infinitely thick formation, i.e.

[0117] In formulas (8)-(11), ε is the blackness of the continuous casting billet; σ is the Stefan-Boltzmann constant, which is 5.67×10 -8 , unit is m 2 ·K 4 ; T is the continuous casting billet temperature, unit is K; T ais the ambient temperature, in K; h is the natural convection heat transfer coefficient;

[0118] Step S525, obtain the temperature T of the hot-delivered steel at time k Nj,k ,j=1,2,3…,k=1,2,3…,N j Indicates continuous casting billet.

[0119] When establishing the heat transfer model of the continuous casting billet in roller conveyance and the heat transfer model of the continuous casting billet in the stacking air cooling process at the slow cooling stacking position, the heat conduction formula (1) and formula (6) are solved by formula (2) and formula (7) respectively. This is to discretize space and time and convert continuous variables into discrete node values. In this way, it can be converted into an algebraic equation. In the specific solution process, it is necessary to reasonably determine the grid size and time step. Figure 4 As shown in the figure, Δx is the spatial step size in the width direction of the continuous casting billet, and Δy is the spatial step size in the thickness direction of the continuous casting billet. The example in the figure shows the node (i, j). To obtain accurate and reliable results, it is necessary to process boundary conditions and initial conditions, which correspond to the various subsequent condition settings mentioned above.

[0120] The initial start time t0 is set when the continuous casting slab is cut. The temperature calculation of the continuous casting slab is completed every Δt. The slab number is used as the index, and the size information, chemical composition information, steel type information, rolling plan information, and temperature field information are integrated. The temperature field calculation of the continuous casting slab is stopped after entering the furnace, and the relevant information indexed by the slab is passed to the heating furnace process control system. The heating furnace process control system performs subsequent temperature field calculations in the continuous casting slab furnace.

[0121] Finally, based on the production process requirements, determine the hot delivery steel grades S1, S2, S3...S i The furnace temperature is T Infur1 、T Infur2 、T Infur3 …T Infuri ; Determine the hot delivery steel grade S according to the rolling plan i , and determine the number of continuous casting billets N of the steel type stacked on the roller table and in the slab warehouse according to the steel type selected for the hot feeding furnace plan j Temperature T at time k Nj,k ; Then the deviation between the temperature at time k and the temperature entering the furnace is: Δ Nj,k =|T Nj,k -T Infuri |;

[0122] Δ Nj,k The preset allowable deviation δ i Compare and satisfy Δ Nj,k <δ i Continuous casting billet N j For hot-feed steel grade Si In order to best prepare the continuous casting billet for entering the furnace, the selected continuous casting billet will then be transported to the roller conveyor in front of the heating furnace or hoisted to the roller conveyor in front of the heating furnace, and then transported to the front of the heating furnace and put into the furnace.

[0123] In summary, the method for preferential hot delivery and hot loading of continuous casting billets based on an information-physical system provided in this application constructs an information-physical system for the hot delivery and hot loading process of continuous casting billets, and based on this system realizes the mapping correspondence between the physical and virtual objects in the hot delivery and hot loading process, completes the real-time simulation calculation of the temperature field of the continuous casting billets, and selectively selects the continuous casting billets to be loaded into the furnace according to the simulated continuous casting billet temperature and rolling plan, solves the problems of difficult measurement of the continuous casting billet temperature and large temperature fluctuations of the continuous casting billets when hot-charged into the furnace, reduces the changes in the furnace operation process and product quality problems caused by the temperature of the hot-charged continuous casting billets, improves the hot charging efficiency, and reduces energy consumption.

[0124] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as such herein, will not be interpreted in an idealized or overly formal sense.

[0125] The meaning of "and / or" in this application means that both situations where each exists alone or both exist at the same time are included.

[0126] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0127] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A method for preferential hot delivery and hot charging of continuous casting billets based on a cyber-physical system, characterized by: The specific steps include: Step S1: constructing a cyber-physical system for the hot delivery and hot charging process of continuous casting billets, wherein the data sources of the cyber-physical system are obtained from the continuous casting machine process control system, the continuous casting basic automation system, the heating furnace process control system, the heating furnace basic automation system, the rolling mill process control system, the rolling mill basic automation system, and the manufacturing execution system; Step S2: establishing a physical model of the continuous casting billet hot delivery and hot charging process, wherein the physical model includes a continuous casting machine, a heating furnace, a rolling mill, a roller table, a cutting device, a deburring machine, a stacking table, a slow cooling stacking position, a testing device, and the continuous casting billet; Step S3: The cyber-physical system realizes information interaction with the physical model through the industrial Internet, where the information used for interaction includes continuous casting plan of the continuous casting machine, continuous casting production information of the continuous casting machine, rolling plan, rolling information of the rolling mill, heating furnace loading and unloading information, continuous casting billet information in the heating furnace, continuous casting billet information on the roller table, stacked continuous casting billet information, production process requirements and standard information; Step S4: Based on the information exchanged in step S3, the dynamic position of the continuous casting billet is mapped to the cyber-physical system. The dynamic position includes the actual transportation process and position of the continuous casting billet from the continuous casting machine to the heating furnace during the hot delivery and hot charging process, forming a mapping between the virtual continuous casting billet and the actual continuous casting billet; Step S5: Based on the information exchanged in step S3, a real-time two-dimensional temperature field model of the continuous casting billet is established to simulate the temperature field of the continuous casting billet from the continuous casting machine to the heating furnace, and the temperature field of the continuous casting billet at each stage of the hot delivery and hot charging process is calculated in real time; The temperature field of the continuous casting billet at each stage is obtained by establishing a heat transfer model for the continuous casting billet during roller conveyance and a heat transfer model for the continuous casting billet during stacking and air cooling at the slow cooling stacking position. Step S6: Based on step S5, the calculated continuous casting billet temperature is compared with the furnace entry temperature required by the production process, and the optimal continuous casting billet for entering the furnace is determined based on the comparison deviation and the preset allowable deviation.

2. The method for preferential hot delivery and hot charging of continuous casting slabs based on cyber-physical systems according to claim 1, characterized in that: The hot delivery and hot charging process of continuous casting slabs includes the following steps: Step S11: starting the continuous casting machine to produce and cut the continuous casting billet; Step S12: performing finishing operations on the continuous casting billet; Step S13: transporting the finished continuous casting billet to roller conveyor section 1. If the continuous casting billet is directly hot-rolled, proceed to step S15; if the continuous casting billet is not directly hot-rolled, proceed to step S14; Step S14: The continuous casting slab is transported to the stacking platform, hoisted off the production line and then stacked to cool. After cooling to a preset temperature, the continuous casting slab is hoisted back on the production line and transported to the stacking platform again. Step S15: transporting the continuous casting slab to roller conveyor section 2 for transportation; Step S16: The continuous casting billet is transported by the roller conveyor in section 2 to the roller conveyor in front of the heating furnace, and then transported to the heating furnace, completing the hot delivery and hot charging process of the continuous casting billet.

3. The method for preferential hot delivery and hot charging of continuous casting slabs based on cyber-physical systems according to claim 1, characterized in that: The continuous casting machine process control system determines the continuous casting plan of the continuous casting machine, including the information of the billet currently being produced and the plan of the billet to be produced, specifically including the billet size data, the chemical composition of the billet and the billet slab number; The continuous casting basic automation system is used for real-time tracking of continuous casting billet positions and collection of on-site detection signals; The heating furnace process control system calculates the heating rate based on the billet's entry temperature and time; and calculates the temperature field in the furnace based on the time in the furnace and the heating time and temperature of each section in the furnace. The heating furnace basic automation system is used to control the temperature detection, heat detection information and position tracking of roller conveyor section 1, roller conveyor section 2 and the roller conveyor in front of the heating furnace; The rolling mill process control system is used to transmit the rolling plan to the heating furnace. The rolling plan contains the rolling information of the rolling mill, including the steel type plan to be loaded into the furnace and the number of rolling blocks; The basic automation system of the rolling mill controls the transition between the furnace roller table and the mill roller table, and also controls the motor and hydraulic systems during the rolling process. The manufacturing execution system monitors all information in the process of hot delivery and hot loading of continuous casting billets in real time, including smelting plan, continuous casting plan, rolling mill plan, billet size information, steel grade information, chemical composition information, billet entry, exit and warehouse location information.

4. The method for preferential hot delivery and hot charging of continuous casting slabs based on a cyber-physical system according to claim 1, characterized in that: According to the continuous casting billet information and detection instrument information stored in the cyber-physical system, a real-time two-dimensional temperature field model of the continuous casting billet is established.

5. The method for preferential hot delivery and hot charging of continuous casting slabs based on cyber-physical systems according to claim 4, characterized in that: The establishment of a heat transfer model for continuous casting slabs during roller transport specifically includes the following steps: Step S511, considering the heat transfer of the continuous casting billet in the thickness and width directions, a two-dimensional coordinate system is established with the center of the continuous casting billet as the origin, the width direction as the x-axis, and the thickness direction as the y-axis, that is, the heat transfer of the continuous casting billet is simplified to two-dimensional heat transfer; Step S512, simplifying the heat transfer between the upper and lower surfaces of the continuous casting billet, and the heat transfer between the continuous casting billet surface and the environment is carried out in two ways: radiation and convection; Step S513, establishing the control equation of the heat transfer model of the continuous casting billet during roller transportation: In formula (1), ρ is the density of the continuous casting billet, in kg / m 3 ; C p is the specific heat capacity of the continuous casting billet, in J / (Kg·K); λ is the thermal conductivity of the continuous casting billet, in W / (m·K); T is the temperature of the continuous casting billet, in K; t is the unit time, in s; x is the coordinate in the width direction of the continuous casting billet, y is the coordinate in the thickness direction of the continuous casting billet, in m; Step S514, use explicit difference equation to solve formula (1) and obtain In formula (2), represents the temperature of node (i, j) at time k+1; represents the temperature of node (i, j) at time k; represents the temperature of node (i+1,j) at time k; represents the temperature of node (i-1, j) at time k; represents the temperature of node (i, j+1) at time k; represents the temperature of the node (i, j-1) at time k; Δt is the time step, Δx is the spatial step in the width direction of the continuous casting billet, and Δy is the spatial step in the thickness direction of the continuous casting billet; Step S515: Set the initial conditions and boundary conditions of formula (2). The initial conditions are: T(x,y,t)| t＝0 =T cut (x,y) (3); The boundary conditions are: In formulas (3), (4) and (5), T cut is the temperature of the continuous casting billet when cutting is completed; ε is the blackness of the continuous casting billet; σ is the Stefan-Boltzmann constant, which is 5.67×10 -8 , unit is m 2 ·K 4 ; T is the continuous casting billet temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient; Step S516, obtain the temperature T of the hot steel entering the furnace Infuri ,i=1,2,3….

6. The method for preferential hot delivery and hot charging of continuous casting slabs based on cyber-physical systems according to claim 4, characterized in that: Based on the production process requirements, determine the hot delivery steel grades S1, S2, S3...S i The furnace temperature is T Infur1 、T Infur2 、T Infur3 …T Infuri ; Determine the hot delivery steel grade S i Continuous casting billet N j Temperature T at time k Nj,k ; Set the time when the continuous casting billet is cut as the initial starting time t0, and complete the temperature calculation of the continuous casting billet every interval Δt. The deviation between the temperature at time k and the temperature entering the furnace is: Δ Nj,k =|T Nj,k -T Infuri |; Δ Nj,k The preset allowable deviation δ i Compare and satisfy Δ Nj,k <δ i Continuous casting billet N j For hot-feed steel grade S i Optimal continuous casting billet for furnace entry.

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