Continuous casting billet preferential hot delivery and hot charging method based on information physical system

Abstract

The invention relates to a continuous casting billet preferential hot delivery and hot charging method based on an information physical system, which constructs the information physical system of a continuous casting billet hot delivery and hot charging process, realizes mapping correspondence of real objects and virtuality in the hot delivery and hot charging process based on the system, and completes real-time simulation calculation of a continuous casting billet temperature field. And according to the temperature of the continuous casting blank and the rolling plan which are subjected to simulation calculation, the continuous casting blank to be charged is preferentially selected. According to the method, the problems that hot-charged continuous casting billet real objects correspond to information, billet temperature is difficult to measure and hot-charged continuous casting billet temperature fluctuation is large are solved, reasonable charging of preferential hot-charged continuous casting billets is achieved, it is guaranteed that the hot charging process is smoothly carried out, furnace technology changes caused by large temperature deviation of the hot-charged continuous casting billets are reduced, hot charging efficiency is improved, and energy consumption is reduced.

Description

Technical Field

[0001] The invention relates to a method for optimal 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 for continuous casting billets is a process method in which the continuous casting billets produced by steelmaking continuous casting are transported to the heating furnace in the steel rolling workshop through rollers after cutting, and then directly loaded into the furnace, or first stacked and slowly cooled, and then loaded into the heating furnace after the temperature of the high-temperature continuous casting billets drops to a certain temperature range. Hot charging and hot delivery technology for continuous casting billets can reduce fuel consumption, save energy and reduce emissions, and reduce costs, so it is widely used in various steel companies.

[0003] Hot charging of continuous casting billets includes direct hot charge rolling (DHCR). Direct hot charge rolling (DHCR) refers to a production process in which the continuous casting billets are not taken off the line after cutting, but are directly transported into the hot rolling heating furnace for heating and rolling through roller conveyor. Taking into account the production plan of steel rolling, the same steel grade and specification are rolled according to one planning unit. The production speed of the continuous casting billets of the continuous casting machine in the direct hot charge process cannot meet the furnace-out speed of the continuous casting billets in steel rolling production. Indirect hot charge rolling of the continuous casting billets by stacking and slow cooling is required in the direct hot charge process of the continuous casting billets. Therefore, hot charging of continuous casting billets also includes indirect hot charge rolling (HCR). Indirect hot charge rolling (HCR) refers to a production process in which the continuous casting billets are taken off the 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 billets enter the heating furnace reaches the required temperature within a specified time or before the billets 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 further 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, so the operator needs 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 the hot-charged continuous casting billets, difficulty in measuring the billet temperature and large temperature fluctuations of the hot-charged continuous casting billets, realizes the reasonable charging of the 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 the large temperature deviation of the 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 the technical problem is:

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

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

[0010] Step S2: establishing a physical model of the hot delivery and hot loading process of the continuous casting billet, 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 information physical system realizes information interaction of the entity physical model through the industrial Internet, and 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 entry and exit 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 interacted in step S3, the dynamic position of the continuous casting billet is mapped to the cyber-physical system, where 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 loading 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 during the hot delivery and hot loading process is calculated in real time;

[0014] 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 conveyance and a heat transfer model of the continuous casting billet during stacking 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] Further, 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: transport the finished continuous casting billet to roller conveyor section 1 for transportation. If the continuous casting billet is directly hot-rolled, proceed to step S15; if the continuous casting billet is hot-rolled, proceed to step S14;

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

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

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

[0023] Further, the continuous casting machine process control system determines the continuous casting plan of the continuous casting machine, including the information of the billet 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 slab number of the billet;

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

[0025] The heating furnace process control system calculates the heating rate based on the billet entry temperature and entry time; calculates the temperature field in the furnace based on the furnace time 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 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 rolling mill to complete the handover between the furnace roller table and the rolling mill roller table, and also completes the control of the motor and hydraulic pressure during the rolling process;

[0029] 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 storage, outbound storage and warehouse location information;

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

[0031] Furthermore, establishing a heat transfer model for continuous casting billets 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 surface and the lower surface of the continuous casting billet, and the heat transfer between the surface of the continuous casting billet 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, using explicit difference equation to solve formula (1), we get

[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; Indicates the temperature of node (i, j+1) at time k; represents the temperature of the node (i, j-1y at time k; Δt is the time step, Δx is the space step in the width direction of the continuous casting billet, and Δy is the space 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 temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient;

[0045] Step S516, obtaining 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 billet during the stacking air cooling process at the slow cooling stacking position specifically includes the following steps:

[0047] Step S521, simplify the stacking 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, establishing 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, in J / (Kg·K); 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, using explicit difference equation to solve formula (1), we get

[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; Indicates the temperature of node (i, j+1) at time k; represents the temperature of the node (i, jx-1) at time k; Δt is the time step, Δx is the space step in the width direction of the continuous casting billet, and Δy is the space 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 are,

[0056] The control equation of the side of continuous casting billet,

[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 a semi-infinitely thick formation, namely

[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 temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient;

[0060] Step S525, obtaining the temperature T of the hot-delivered steel at time k Nj,k ,j=1,2,3…,k=1,2,3…,N j Represents 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 TI nfur1 、T Infur2 、T Infur3 …T Infur ; Determine the hot delivery steel grade S i Continuous casting billet N j The temperature T at time k Nj,k ;

[0062] Set the time when the continuous casting billet is cut as the initial start 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 furnace entry temperature 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 ingot for furnace entry.

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

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

[0066] 2. The method for preferential hot delivery and hot loading of continuous casting billets based on the cyber-physical system provided by the present invention establishes a real-time two-dimensional temperature field model of the continuous casting billets during the transportation process and the stacking process according to the continuous casting billet information and the detection instrument information stored in the cyber-physical system, and can simulate the temperature field of the continuous casting billets from the continuous casting machine to the furnace, so as to achieve the purpose of real-time calculation of the temperature field of each stage such as transportation and stacking of the continuous casting billets, thereby improving the accuracy of the calculation results;

[0067] 3. The method for preferential hot delivery and hot charging of continuous casting billets based on the information-physical system provided by the present invention solves the correspondence between the physical objects and information of the continuous casting billets during the hot charging process, realizes the optional hot charging of the continuous casting billets into the furnace at the temperature required by the process, ensures the smooth progress of the hot charging process, 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0069] Figure 1 It 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 It is a schematic diagram of the network structure of the information-physical system provided by the present invention;

[0071] Figure 3 It is a schematic diagram of a two-dimensional coordinate system established when the heat transfer of the continuous casting billet is simplified to two-dimensional heat transfer provided by the present invention;

[0072] Figure 4It is a schematic diagram of the grid-dividing continuous casting billet for obtaining the temperature field of the continuous casting billet at each stage provided by the present invention. 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. 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 is necessary to enter the furnace to avoid steel blocking. Therefore, the temperature of the slab is not measured during the direct hot charge and indirect hot charge of the continuous casting billet, and it is impossible to achieve a reasonable selection of direct hot charge and indirect hot charge continuous casting billets, resulting in a large difference in the temperature of the hot-charged continuous casting billet, 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 is easy to 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 loading 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. It is a new generation of intelligent ecosystem with self-learning and self-growth capabilities. Before elaborating on the method provided by this application, we first need to understand the specific steps involved in the hot delivery and hot loading 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: transport the finished continuous casting billet to roller conveyor section 1 for transportation. If the continuous casting billet is directly hot-rolled, proceed to step S15; if the continuous casting billet is hot-rolled, proceed to step S14;

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

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

[0081] Step S16: The continuous casting billet is transported by roller conveyor in section 2 to the roller conveyor in front of the heating furnace, and then transported to the heating furnace, thus completing the hot delivery and hot loading 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 the present 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, Manufacturing Execution System) system.

[0083] The equipment involved in the information-physical system constitutes a physical model, including continuous casting machines, heating furnaces, rolling mills, roller tables, cutting equipment, deburring machines, stacking platforms, slow cooling stacking positions, testing equipment and continuous casting billets. In particular, for key equipment such as continuous casting machines, heating furnaces and rolling mills, each has its own control system (including basic automation systems and process control systems), which are the main components of the data sources of the information-physical system mentioned above. Basic automation is mainly PLC (programmable controller) for position control, sequence control, flow regulation, etc. Control actuators such as motors, valves, hydraulic steel, pushers, screws and other equipment; process control systems are based on physical metallurgy and other model process control, continuous casting machine process control system, such as drawing speed setting and liquid level control during continuous casting, heating furnace process control system controls the temperature field, heating time, heating rate, etc. of the slab, and rolling mill process control system mainly calculates the rolling schedule, including the amount of reduction, rolling force, torque, speed, etc.

[0084] The method of solving the problem of difficult measurement of temperature of continuous casting billets and large temperature fluctuation of continuous casting billets in hot charging furnaces in this application is based on the information-physical system, which corresponds the physical object and information of continuous casting billets in the hot charging process, that is, the information-physical system realizes the information interaction of the physical model through the industrial Internet. The information used for interaction includes continuous casting plan of continuous casting machine, continuous casting production information of continuous casting machine, rolling plan, rolling information of rolling mill, information of entering and leaving heating furnace, information of continuous casting billets in heating furnace, information of continuous casting billets on roller, information of stacked continuous casting billets, production process requirements and standard information.

[0085] Specifically, the continuous casting machine process control system provides information on the billet being produced and the billet plan to be produced next, including billet size data, billet chemical composition, billet slab number, etc.; the data used for subsequent model construction include billet surface temperature and internal temperature field, billet slab number, size (length, width, thickness), and chemical composition. The continuous casting basic automation system is mainly for real-time tracking of position and collection of on-site detection signals; it provides position information for model construction, including starting position, time, etc. The heating furnace process control system provides billet entry temperature and furnace entry time, calculates heating rate, furnace time, and heating time and temperature of each section in the furnace, so as to calculate the temperature field in the furnace; the data used for subsequent model construction include furnace atmosphere temperature and furnace entry process standards. The heating furnace basic automation system is mainly for furnace front roller control, the handover of continuous casting machine roller and heating furnace entry roller, temperature detection, heat detection information, and position tracking; among them, the main position information, position and surface temperature during transportation, are used for model calculation and correction. The rolling mill process control system provides the rolling mill plan, passes it to the heating furnace, the steel type plan that needs to be loaded into the furnace, the number of rolling blocks, and the model calculation of the rolling mill itself. The basic automation system of the rolling mill mainly controls the rolling mill to complete the handover between the furnace roller and the rolling mill roller, and the motor and hydraulic control of the rolling process. The manufacturing execution system mainly includes smelting plan, continuous casting plan, rolling mill plan, billet size information, steel type information, chemical composition information, billet storage, out of storage and warehouse location information, etc. These data provide strong support for the construction of subsequent models.

[0086] After clarifying the above interactive information, the next step is to carry out optimal design, realize dynamic position mapping of continuous casting billets on the cyber-physical system, map the actual transportation process and position of 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 billets 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 1 The provided logistics flow chart for hot delivery and hot charging of continuous casting billets takes into account two modes: direct loading into the furnace after cutting or stacking and slow cooling before loading into the furnace. Therefore, during operation, the part involving roller transport is designed as 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 heating furnace, and the temperature field of the continuous casting billet at each stage in the hot delivery and hot loading process is calculated in real time; among which, the temperature field of the continuous casting billet at each stage is obtained by establishing a heat transfer model of the continuous casting billet in roller transportation and a heat transfer model of the continuous casting billet in the stacking air cooling process at the slow cooling stacking position.

[0088] First, the establishment of the heat transfer model of the continuous casting billet in roller transport specifically 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 the 1 / 2 section of the continuous casting billet 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, to establish a two-dimensional coordinate system, 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 surface and the lower surface of the continuous casting billet, and the heat transfer between the surface of the continuous casting billet 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 p The thermal conductivity λ of the continuous casting billet is a function of the continuous casting billet temperature T.

[0094] Step S514, using explicit difference equation to solve formula (1), we get

[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; Indicates 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 space step in the width direction of the continuous casting billet, and Δy is the space 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 cur (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 temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient;

[0102] Step S516, obtaining 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 stacking 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] 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 heat transfer model of the continuous casting billets during the stacking air cooling process is established as follows:

[0106]

[0107] 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, in J / (Kg·K); 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;

[0108] Step S523, using explicit difference equation to solve formula (1), we get

[0109]

[0110] 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; Indicates 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 space step in the width direction of the continuous casting billet, and Δy is the space step in the thickness direction of the continuous casting billet;

[0111] Step S524, setting the boundary conditions of formula (7), respectively:

[0112] The governing equations for ground heat transfer are,

[0113] The control equation of the side of continuous casting billet,

[0114] The surface control equation of the continuous casting billet numbered 1 is:

[0115] The surface control equation of the continuous casting billet numbered i, T g =T c , where T c is the solution for a semi-infinitely thick formation, namely

[0116] 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 temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient;

[0117] Step S525, obtaining the temperature T of the hot-delivered steel at time k Nj,k ,j=1,2,3…,k=1,2,3…,N j Represents continuous casting billet.

[0118] When establishing the heat transfer model of the continuous casting billet in roller conveyor transportation 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, they can be converted into algebraic equations. 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 length of the continuous casting billet in the width direction, Δy is the spatial step length of the continuous casting billet in the thickness direction, and the example in the figure shows the node (i, j). In order to obtain accurate and reliable results, it is also necessary to process the boundary conditions and initial conditions, which correspond to the various subsequent condition settings mentioned above.

[0119] The initial start time t0 is set when the continuous casting billet is cut. The temperature calculation of the continuous casting billet is completed every Δt. The billet number is used as the index to integrate the size information, chemical composition information, steel type information, rolling plan information, and temperature field information. The temperature field calculation of the continuous casting billet is stopped after entering the furnace, and the relevant information indexed by the billet is passed to the heating furnace process control system. The heating furnace process control system performs subsequent temperature field calculations in the continuous casting billet furnace.

[0120] Finally, based on the production process requirements, 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 this 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 The temperature T at time k Nj,k ; Then the temperature deviation at time k and the furnace entry temperature is: Δ Nj,k =|T Nj,k -T Infuri |;

[0121] 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 In order to optimally prepare the continuous casting billet for entering the furnace, the selected continuous casting billet is then transported to the roller table in front of the heating furnace through a roller table or hoisted thereto, and then transported to the front of the heating furnace and entered into the furnace.

[0122] In summary, the method for preferential hot delivery and hot loading of continuous casting billets based on information-physical system provided by the present application constructs an information-physical system for the hot delivery and hot loading process of continuous casting billets, and based on the 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, thereby solving 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, reducing the changes in the furnace operating 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.

[0123] 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 those generally 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 the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0124] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0125] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0126] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for optimal hot delivery and hot loading of continuous casting billets based on cyber-physical system, characterized in that: The specific steps include: Step S1: constructing a cyber-physical system for hot delivery and hot loading of continuous casting billets, wherein the data source of the cyber-physical system is obtained from a continuous casting machine process control system, a continuous casting basic automation system, a heating furnace process control system, a heating furnace basic automation system, a rolling mill process control system, a rolling mill basic automation system, and a manufacturing execution system; Step S2: establishing a physical model of the hot delivery and hot loading process of the continuous casting billet, 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 information physical system realizes information interaction of the entity physical model through the industrial Internet, and 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 entry and exit 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 interacted in step S3, the dynamic position of the continuous casting billet is mapped to the cyber-physical system, where 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 loading 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 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 conveyance and a heat transfer model of the continuous casting billet during stacking 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 loading of continuous casting billets based on cyber-physical system 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: transport the finished continuous casting billet to roller conveyor section 1 for transportation. If the continuous casting billet is directly hot-rolled, proceed to step S15; if the continuous casting billet is hot-rolled, proceed to step S14; Step S14: the continuous casting billet is transported to the stacking platform, lifted off the production line and then cooled at the stacking position, and then lifted back on the production line after cooling to a preset temperature, and the continuous casting billet is transported to the stacking platform again; Step S15: transporting the continuous casting billet to the roller conveyor section 2 for transportation; Step S16: The continuous casting billet is transported by roller conveyor in section 2 to the roller conveyor in front of the heating furnace, and then transported to the heating furnace, thus completing the hot delivery and hot loading process of the continuous casting billet.

3. The method for preferential hot delivery and hot charging of continuous casting billets based on cyber-physical system 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 being produced and the plan of the billet to be produced, including billet size data, chemical composition of the billet and the slab number of the billet; The continuous casting basic automation system is used for real-time tracking of the continuous casting billet position and collection of on-site detection signals; The heating furnace process control system calculates the heating rate based on the billet entry temperature and entry time; calculates the temperature field in the furnace based on the furnace time 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 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 rolling mill to complete the handover between the furnace roller table and the rolling mill roller table, and also completes the control of the motor and hydraulic pressure 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 storage, outbound storage and warehouse location information.

4. The method for optimal hot delivery and hot charging of continuous casting billets based on 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 optimal hot delivery and hot loading of continuous casting billets based on cyber-physical system according to claim 4, characterized in that: The establishment of the heat transfer model of continuous casting billet in roller conveyor 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 surface and the lower surface of the continuous casting billet, and the heat transfer between the surface of the continuous casting billet 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, using explicit difference equation to solve formula (1), we get 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; Indicates 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 space step in the width direction of the continuous casting billet, and Δy is the space 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 temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient; Step S516, obtaining the temperature T of the hot steel entering the furnace Infuri ,i=1,2,3…。 6. The method for preferential hot delivery and hot loading of continuous casting billets based on cyber-physical system according to claim 4, characterized in that: Establishing a heat transfer model for continuous casting billets during stacking air cooling at a slow cooling stacking position specifically includes the following steps: Step S521, simplify the stacking 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... Step S522, establishing the control equation of the heat transfer model of the continuous casting billet during the stacking air cooling process: 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, in J / (Kg·K); 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; Step S523, using explicit difference equation to solve formula (1), we get 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; Indicates 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 space step in the width direction of the continuous casting billet, and Δy is the space step in the thickness direction of the continuous casting billet; Step S524, setting the boundary conditions of formula (7), respectively: The governing equations for ground heat transfer are, The control equation of the side of continuous casting billet, The surface control equation of the continuous casting billet numbered 1 is: The surface control equation of the continuous casting billet numbered i, T g =T c , where T c is the solution for a semi-infinitely thick formation, namely 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 temperature, unit is K; T a is the ambient temperature, in K; h is the natural convection heat transfer coefficient; Step S525, obtain the temperature T of the hot steel at time k Nj,k ,j=1,2,3…,k=1,2,3…,N j Represents continuous casting billet.

7. The method for optimal hot delivery and hot charging of continuous casting billets based on cyber-physical system 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 The temperature T at time k Nj,k ; Set the time when the continuous casting billet is cut as the initial start 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 furnace entry temperature 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 ingot for furnace entry.

Images