Scheduling plan-embedded casting blank temperature drop calculation method in casting-rolling connection process

Abstract

The invention relates to the technical field of continuous casting and rolling production, in particular to a casting blank temperature drop calculation method in a casting-rolling connection process embedded with a scheduling plan, which comprises the following steps: establishing a casting blank whole-process heat transfer model, and calculating the temperature of a casting blank in real time; according to the casting blank temperature information and the production order information, a hot rolling scheduling plan is made in real time; and performing production scheduling according to the hot rolling scheduling plan. According to the method, in the casting and rolling connection process, a casting blank temperature drop calculation method is embedded into a scheduling plan to achieve corresponding functions, the temperatures of all casting blanks from the time after cutting to the time before the casting blanks enter a heating furnace can be rapidly, accurately and stably calculated and predicted in real time, and the obtained casting blank temperature information is used for formulating a hot rolling scheduling plan. Therefore, the problems of casting blank hot feeding, hot charging and red feeding crack surface defects, intensified hot casting blank oxidation burning loss and the like are effectively solved, the metal yield is increased, and the utilization of heat of the cut casting blank is improved.

Description

Technical Field

[0001] The invention relates to the technical field of continuous casting and rolling production, and in particular to a method for calculating the temperature drop of a slab in a casting and rolling connection process embedded in a scheduling plan. Background Art

[0002] The hot delivery and hot charging process of ingots is a production process that uses the heat of ingots after cutting and closely connects with the rolling process with corresponding measures. Compared with cold charging, hot delivery and hot charging of ingots has the advantages of saving energy, improving the yield rate, saving metal consumption, improving product quality, simplifying the production process, etc., which is of great significance to promoting the development of steel production towards continuous, low-cost, high-quality and high-efficiency. However, due to the harsh environment such as noise, exhaust gas and high temperature near the ingot stack in the ingot warehouse, it is almost impossible for the staff to carry out temperature testing of the ingots. In addition, when formulating the scheduling plan, the key parameter of the ingot temperature cannot be referred to, resulting in major defects in the plan formulation, which directly affects the level of hot delivery and hot charging of ingots. The defective plan will cause surface defects of ingot red delivery cracks, mixed loading of hot and cold ingots, increased gas consumption, waste of heat of ingots after cutting, and increased oxidation and burning of ingots, which are not conducive to energy saving and consumption reduction, resulting in a large waste of manpower and material resources.

[0003] Since the actual effect of hot delivery and hot loading of billets is mainly affected by the scheduling plan, it is generally believed that improving the scheduling plan is the key to improving the level of hot delivery and hot loading of billets, reducing energy loss and billet quality defects. To achieve this goal, the temperature of each billet in the billet warehouse must first be obtained through temperature calculation methods to greatly reduce the occurrence of unreasonable phenomena such as mixed cold and hot loading.

[0004] Some researchers have proposed using integer programming models or spatiotemporal network models to improve the regularity of billet stacking. In existing domestic public reports, Chinese patent CN201410307353.6 proposes a control method for hot rolling preparation in a billet warehouse, which optimizes the scheduling plan by making decisions on the extraction order of billets in the same batch plan, thereby reducing the amount of stacking and preparation time, but the patent does not involve optimizing the scheduling plan from the perspective of billet temperature; similarly, Chinese patent CN20211035454.8 proposes a billet feeding control method and device, which exchanges the positions of each billet in the current billet feeding sequence, takes the billet feeding sequence with the highest feeding efficiency as the optimal slab feeding sequence, and controls the overhead crane to perform slab feeding operations according to the sequence, but the patent does not mention calculating the billet temperature and embedding it into the scheduling plan.

[0005] Chinese patent CN202311047493.X proposes a finishing method and system for improving hot delivery and hot loading of ingots. The online heat inspection system of the ingot is used to identify whether the ingot has defects and the location of the defects, and different furnace flow directions are set for different ingots, in order to improve the hot delivery and hot loading rate. The method has a few similarities with the present invention, but the online heat inspection system of the patent cannot obtain the accurate temperature field of the ingot. Its main purpose is to detect surface defects of the ingot. The online heat inspection system is only used to identify surface defects of the ingot, which is fundamentally different from the temperature drop calculation method of the ingot in the casting and rolling connection process embedded in the scheduling plan.

[0006] Chinese patent CN116237374A proposes a method for hot charging and hot delivery of a heating furnace based on temperature simulation of the billet transportation process. It requires the formulation of a rolling plan twice, which is cumbersome and affects work efficiency. Moreover, the hot rolling plan and temperature calculation module of this patent are separated, and the integrity of the steel plant operating system is not improved. In addition, this patent can only predict the billet temperature, but cannot calculate the billet temperature in real time, resulting in inaccurate calculation results. At the same time, this patent does not provide a specific heat transfer model construction and the corresponding specific boundary condition formulas and parameters, nor does it provide methods and ideas for reducing the quality defect problem of red delivery cracks in billets.

[0007] In summary, there is currently a lack of an effective, reliable and comprehensive method to improve the level of hot delivery and hot loading of hot rolled ingots, in order to address the problems of low feeding efficiency of hot rolled ingots, mixed hot and cold loading in the heating furnace, and heat loss of ingots after cutting. Summary of the invention

[0008] 1. Technical issues to be resolved To solve the technical problems in the prior art of how to overcome the low feeding efficiency of the traditional hot delivery and hot loading of hot rolled ingots, the mixed loading of hot and cold in the heating furnace, and the heat loss of the ingots after cutting.

[0009] (II) Technical solution The present invention provides a method for calculating the temperature drop of a slab during a casting and rolling connection process embedded in a scheduling plan, comprising: Step S100: Establishing a heat transfer model for the entire process of casting; the heat transfer model for the entire process includes: a mathematical model for roller conveying process, a mathematical model for clamp crane conveying process, a mathematical model for transverse vehicle conveying process, a mathematical model for cross-car conveying process, a mathematical model for pallet conveying process and a mathematical model for stacking process; Step S110: sorting out the heat transfer links included in the important flow from flame cutting to entering the heating furnace; Step S120: establishing a heat transfer model for the entire casting process according to the heat transfer numerical method, important flow directions and heat transfer links; Step S200: Calculate the temperature of the casting billet in real time according to the heat transfer model of the entire casting process to obtain the temperature information of the casting billet; Step S300: formulating a hot rolling scheduling plan in real time according to the ingot temperature information and the production order information; Step S400: Scheduling production according to the hot rolling schedule.

[0010] Further, step S200 includes: Step S210: obtaining temperature calculation data according to the heat transfer model of the entire casting process, the temperature calculation data including: the first moment, casting information and environmental parameters; Step S220: Calculate the temperature information of the first ingot at the first moment based on the environmental parameters. After the calculation is completed, calculate the temperature information of the next ingot until all the ingot temperature information is calculated. Store the calculation results and calculate the temperature information of the ingot at the next moment until the operator terminates the calculation or the calculation time coincides with the current time.

[0011] Furthermore, important flows include: qualified flows, flows requiring machine cleaning, flows awaiting inspection, and flows for special circumstances.

[0012] Furthermore, the heat transfer link includes: roller conveyor transport link, clamp crane transport link, transverse vehicle transport link, cross-car transport link, pallet transport link and stacking link.

[0013] Furthermore, the mathematical model of the roller transport process is used to calculate the heat flux density of the upper surface of the ingot, the heat flux density of the lower surface of the ingot and the heat flux density of the side surface of the ingot in the roller transport link.

[0014] Furthermore, the mathematical model of the clamp crane transportation process is used to calculate the heat flux density of the upper surface of the ingot, the heat flux density of the lower surface of the ingot and the heat flux density of the side surface of the ingot in the clamp crane transportation link.

[0015] Furthermore, the mathematical model of the transverse vehicle transportation process is used to calculate the heat flux density of the upper surface of the ingot, the heat flux density of the lower surface of the ingot and the heat flux density of the side surface of the ingot in the transverse vehicle transportation link.

[0016] Furthermore, the mathematical model of the straddle carrier transport process is used to calculate the heat flux density of the upper surface of the ingot, the heat flux density of the lower surface of the ingot and the heat flux density of the side surface of the ingot in the straddle carrier transport link.

[0017] Furthermore, the mathematical model of the pallet transport process is used to calculate the heat flux density of the upper surface of the ingot, the heat flux density of the lower surface of the ingot, the heat flux density of the side surface of the ingot and the heat flux density of the contact surface between adjacent ingots in the pallet transport link.

[0018] Furthermore, the mathematical model of the stacking process is used to calculate the heat flux density of the upper surface of the billet at the top of the billet stack, the heat flux density of the lower surface of the billet at the top of the billet stack, the heat flux density of the side surface of the billet stack, the heat flux density of the upper surface of the middle billet, the heat flux density of the lower surface of the middle billet, the heat flux density of the upper surface of the billet at the bottom of the billet stack, and the heat flux density of the lower surface of the billet at the bottom of the billet stack in the stacking link.

[0019] (III) Beneficial effects The present invention mentions a method for calculating the temperature drop of a billet during a casting and rolling connection process embedded in a scheduling plan, comprising: establishing a heat transfer model for the entire process of the billet; calculating the billet temperature in real time based on the heat transfer model for the entire process of the billet to obtain billet temperature information; formulating a hot rolling scheduling plan in real time based on the billet temperature information and production order information; and scheduling production according to the hot rolling scheduling plan.

[0020] The present invention can obtain the temperature information of the billet in real time by calculating the temperature of the billet during the casting and rolling connection process, and use the obtained temperature information for the hot rolling scheduling plan. This method can be directly applied under existing production conditions, with low transformation cost, and has a good improvement effect on the hot rolling billet feeding method. The constructed billet full process heat transfer model can calculate the billet temperature in real time, provide a real-time temperature basis for the scheduling plan, and can both calculate and simulate the billet temperature in the billet warehouse in real time. If it is in the temperature range where the red delivery crack hot delivery defect occurs, it will remind that hot loading is not allowed and predict the time to meet the hot loading conditions, thereby reducing the occurrence of red crack quality defects and the waste of manpower and material resources; it can avoid the mixed loading of hot and cold billets, reduce the oxidation and burning of hot billets, reduce the energy consumption of heating furnaces, and improve the metal recovery rate; it can derive a transportation method that is conducive to the insulation of billets, improve the utilization of billet heat, and reduce energy consumption; it can accurately predict the time required for the hot billet temperature to drop to the furnace loading limit temperature, and improve the hot loading rate; it enables the operator to understand the temperature distribution in the billet warehouse. The heat transfer model constructed by this method can calculate the temperature of the ingot in real time and predict the hot charging time, so that the ingot can be hot charged under the hot charging conditions with minimum heat energy loss, thereby reducing heat loss, improving the hot charging rate, reducing the storage area occupation, and promoting the improvement of the hot rolling ingot feeding method. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings; Figure 1 It is a schematic diagram of the production and transportation and stacking state of the slabs in the casting and rolling connection process in the casting and rolling connection process in which the method for calculating the temperature drop of the slabs embedded in the scheduling plan mentioned in the present invention is embedded in the scheduling plan; Figure 2 It is a flow chart of a method for calculating the temperature drop of a slab during a casting and rolling connection process embedded in a scheduling plan mentioned in the present invention; Figure 3It is a schematic diagram of a billet library of a method for calculating the temperature drop of a billet in a casting and rolling connection process embedded with a scheduling plan mentioned in the present invention; Figure 4 It is a real-time temperature calculation flow chart of a method for calculating the temperature drop of a slab during a casting and rolling connection process embedded in a scheduling plan mentioned in the present invention; Figure 5 It is a predicted temperature calculation flow chart of a method for calculating the temperature drop of a slab in a casting and rolling connection process embedded with a scheduling plan mentioned in the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0023] Hot delivery and hot charging of ingots has become an important measure for energy conservation and consumption reduction in steel enterprises, with many advantages, but the accompanying prominent problem is that when many important steel grades are hot charged, the crack rate on the surface of the steel plate increases significantly, and surface cracks become an important problem that troubles production and quality. This problem is mainly related to the temperature of the ingot when it is hot charged. In order to avoid the quality problem of red delivery cracks, the operators of the factory now cool down the ingots. However, since they do not know the temperature information of the ingots, they often choose to stack the steel grades that are prone to red cracks for too long, which will not only lead to the loss of heat energy contained in these ingots, reduce the hot charging rate of the steel plant, increase energy consumption, but also lead to excessive occupation of the ingot warehouse area. The heat transfer model of the whole process of ingots constructed by this method can calculate the temperature of the ingots in real time, and can predict the time when the ingots meet the hot charging conditions, so that the ingots can be hot charged in the state of minimum heat energy loss when they meet the hot charging conditions, thereby reducing the heat loss caused by too long stacking time, and can also improve the hot charging rate of the steel plant, reduce the occupation time of the ingot warehouse area, and further improve the hot rolling ingot feeding method.

[0024] Specifically, refer to Figure 2 In a first aspect, the present invention provides a method for calculating the temperature drop of a slab during a casting and rolling connection process embedded in a scheduling plan, comprising: Step S100: establishing a heat transfer model for the entire casting process.

[0025] In this technical solution, step S100 includes: Step S110: sort out the heat transfer links included in all important flows from flame cutting to heating furnace. The main flows include qualified flows, flows requiring machine cleaning, flows to be inspected, flows for special situations, etc., and sort out the links in the transportation and stacking process, such as roller conveyor transportation, clamp crane transportation, transverse vehicle transportation, cross-car transportation, pallet transportation, stacking, etc.

[0026] refer to Figure 1 , Figure 1 The video demonstrates the actual production operations of warehousing, warehousing, and stacking, as well as roller conveyors, clamp cranes, and stacking positions.

[0027] Specifically, in the mathematical model of the roller conveyor process: In the roller conveyor link, the calculation formula for the heat flux density on the upper surface of the ingot is: (1); In the roller transport process, the heat flux density on the lower surface of the ingot is calculated as follows: (2); In the roller conveyor link, the calculation formula for the heat flux density on the side surface of the ingot is: (3); In equations (1), (2) and (3), q 1 Expressed as the heat flux density on the upper surface; q 2 Expressed as the heat flux density of the lower surface; q 3 Expressed as the heat flux density on the side surface; It is expressed as the surface temperature of the ingot, in °C; It is expressed as the ambient temperature of the casting in °C; It is expressed as the heat transfer coefficient of the upper surface of the casting during the roller conveyor transport process, in units of ; It is expressed as the heat transfer coefficient of the lower surface of the casting in the roller conveyor link, in units of ; It is expressed as the heat transfer coefficient of the side surface of the casting billet in the roller conveyor link, and the unit is ; It is expressed as emissivity; It is expressed as the Stefan-Boltzmann constant, in units of .

[0028] Specifically, in the mathematical model of the clamp crane transportation process: In the clamp crane transportation link, the calculation formula for the heat flux density on the upper surface of the ingot is: (4); In the clamp crane transportation link, the calculation formula for the heat flux density on the lower surface of the ingot is: (5); In the clamp crane transportation link, the calculation formula for the heat flux density on the side surface of the ingot is: (6); In equations (4), (5) and (6), q 4 Expressed as the heat flux density on the upper surface, q 5 Expressed as the heat flux density on the lower surface, q 6 Expressed as the heat flux density on the side surface, It is expressed as the surface temperature of the ingot, in °C; It is expressed as the ambient temperature of the casting in °C. It is expressed as the heat transfer coefficient of the upper surface of the ingot during the clamp crane transportation process, in units of ; It is expressed as the heat transfer coefficient of the lower surface of the ingot during the clamp crane transportation process, in units of ; It is expressed as the heat transfer coefficient of the side surface of the ingot during the clamp crane transportation process, in units of ; It is expressed as the area thermal resistance between the ingots, in units of ; It is expressed as the area contact thermal resistance between the ingots, in units of ; It is expressed as emissivity; It is expressed as the Stefan-Boltzmann constant, in units of .

[0029] Specifically, in the mathematical model of the transverse vehicle transportation process: In the traverse vehicle transportation link, the calculation formula for the heat flux density on the upper surface of the ingot is: (7); In the traverse vehicle transportation link, the calculation formula for the heat flux density on the lower surface of the ingot is: (8); In the traverse vehicle transportation link, the calculation formula for the heat flux density on the side surface of the ingot is: (9); In equations (7), (8) and (9), q 7 Expressed as the heat flux density on the upper surface, q 8 Expressed as the heat flux density on the lower surface, q 9 Expressed as the heat flux density on the side surface, It is expressed as the surface temperature of the ingot, in °C; It is expressed as the ambient temperature of the casting in °C; It is expressed as the surface temperature of the transverse vehicle in °C; It is expressed as the heat transfer coefficient of the upper surface of the ingot during the transport process of the transverse vehicle, in units of ; It is expressed as the heat transfer coefficient of the side surface of the ingot during the transport process of the transverse vehicle, in units of ; It is expressed as the area thermal resistance between the ingot and the transverse car, in units of ; It is expressed as the area contact thermal resistance between the ingot and the transverse transfer car, in units of ; It is expressed as emissivity; It is expressed as the Stefan-Boltzmann constant, in units of .

[0030] Specifically, in the mathematical model of the straddle carrier transport process: During the transport process of the straddle carrier, the heat flux density on the upper surface of the ingot is calculated as follows: (10); During the transport process of the straddle carrier, the heat flux density on the lower surface of the ingot is calculated as follows: (11); During the transport process of the straddle carrier, the heat flux density on the side surface of the ingot is calculated as follows: (12); In equations (10), (11) and (12), q 10 Expressed as the heat flux density on the upper surface, q 11 Expressed as the heat flux density on the lower surface, q 12 Expressed as the heat flux density on the side surface, It is expressed as the surface temperature of the ingot, in °C; It is expressed as the ambient temperature of the casting in °C; It is expressed as the surface temperature of the straddle car in °C; It is expressed as the heat transfer coefficient of the upper surface of the ingot during the transport process of the straddle car, in units of ; It is expressed as the heat transfer coefficient of the side surface of the ingot during the transport process of the straddle carrier, in units of ; It is expressed as the area thermal resistance between the ingot and the cross-car, in units of ; It is expressed as the area contact thermal resistance between the billet and the cross-car, in units of ; It is expressed as emissivity; It is expressed as the Stefan-Boltzmann constant, in units of .

[0031] Specifically, in the mathematical model of the pallet transport process: During the transportation of the stacking platform, the heat flux density on the upper surface of the ingot is calculated as follows: (13); During the transportation of the stacking platform, the heat flux density on the lower surface of the ingot is calculated as follows: 14); During the transportation of the stacking platform, the calculation formula for the heat flux density on the side surface of the ingot is: (15); In the process of stacking pallet transportation, the calculation formula of the heat flux density of the contact surface between adjacent ingots is: (16); In equations (13), (14), (15) and (16), q 13 Expressed as the heat flux density on the upper surface, q 14 Expressed as the heat flux density on the lower surface, q 15 Expressed as the heat flux density on the side surface, q 16 It is expressed as the heat flux density of the contact surface between the ingots, It is expressed as the surface temperature of the ingot, in °C; It is expressed as the ambient temperature of the casting in °C; It is expressed as the surface temperature of the pallet during the pallet transportation process, in degrees Celsius; It is expressed as the heat transfer coefficient of the upper surface of the ingot during the transportation of the stacking platform, in units of ; It is expressed as the heat transfer coefficient of the side surface of the ingot during the transportation of the stacking platform, in units of ; It is expressed as the area thermal resistance between the ingot and the cross-car, in units of ; It is expressed as the contact heat between the billet and the cross-car, in units of ; It is expressed as the surface temperature of the upper layer of two adjacent ingots, in °C; It is expressed as the surface temperature of the lower layer of two adjacent ingots, in degrees Celsius.

[0032] Specifically, in the mathematical model of the stacking process: In the stacking process, the heat flux density on the upper surface of the ingot at the top of the ingot stack is calculated as follows: (17); In the stacking process, the heat flux density on the lower surface of the ingot at the top of the ingot stack is calculated as follows: (18); In the stacking process, the calculation formula for the heat flux density on the side surface of the ingot stack is: (19); In the stacking process, the calculation formula for the heat flux density on the upper surface of the intermediate ingot is: (20); In the stacking process, the calculation formula for the heat flux density on the lower surface of the intermediate ingot is: (twenty one); The calculation formula for the heat flux density on the upper surface of the ingot at the bottom of the ingot stack is: (twenty two); The calculation formula for the heat flux density on the lower surface of the ingot at the bottom of the ingot stack is: (twenty three); In equations (17), (18), (19), (20), (21) and (22), q 17 It is expressed as the heat flux density on the top surface of the ingot at the top of the stack, q 18 It is expressed as the heat flux density on the lower surface of the ingot at the top of the stack, q 19 Expressed as the heat flux density on the side surface of the pile, q 20 It is expressed as the heat flux density on the upper surface of the middle ingot, q 21 It is expressed as the heat flux density on the lower surface of the middle ingot, q 22 It is expressed as the heat flux density on the upper surface of the ingot at the bottom of the stack, q 23 It is expressed as the heat flux density on the lower surface of the ingot at the bottom of the stack, and R is expressed as the area thermal resistance between the ingots, in units of ; rth is the area contact heat between the ingots, in units of ; T n Represents the temperature of the current casting block, T n-1 Represents the temperature of the previous ingot, T n+1 Represents the temperature of the next ingot, It is expressed as the surface temperature of the ingot, in °C; It is expressed as the ambient temperature of the casting in °C; It is expressed as the heat transfer coefficient of the upper surface of the ingot in the stacking process, in units of ; It is expressed as the heat transfer coefficient of the side surface of the ingot in the stacking process, in units of ; It is expressed as the initial ground temperature in °C; It is expressed as an equivalent coefficient, with a value of 0.01~0.2; It is expressed as emissivity; It is expressed as the Stefan-Boltzmann constant, in units of .

[0033] In terms of setting boundary conditions, this application sets boundary conditions suitable for model solving for each sub-model. Among them, the mathematical model of the stacking process is more specific and accurate in setting boundary conditions. Different boundary conditions are used according to the specific position of the ingot in the stack, making the calculation closer to the actual situation, thereby ensuring more accurate temperature calculation.

[0034] For the same control equation, different boundary conditions will lead to different results, so the boundary conditions must be selected reasonably. The actual billet warehouse consists of storage space, billets, and transportation tools such as clamp cranes, cross-cars, and roller tables. Figure 3 As shown in the figure, the billet logistics in the billet warehouse is implemented by a variety of facilities and equipment. In actual production, there are a lot of cumbersome logistics operation scheduling and planning management, and there are many heat transfer situations in this process. It is more reasonable to apply different boundary conditions for each situation, that is, to study the heat transfer process of the billet under variable boundary conditions. There are many flow directions of the billet from flame cutting to entering the heating furnace. Under the same conditions, billets with different flow directions will have different thermal histories, resulting in different properties of the billet. After clarifying the flow direction, the billet temperature can be numerically simulated according to the flow direction, that is, applying different boundary conditions to the billet at different links in the flow direction can improve the accuracy of numerical simulation. Therefore, it is necessary to sort out all important flow directions from flame cutting to entering the heating furnace.

[0035] In this technical solution, important flows include qualified flows, flows that need machine cleaning, flows to be inspected, and flows in special situations. Heat transfer links include roller conveyor links, clamp crane conveyor links, transverse vehicle conveyor links, cross-car conveyor links, pallet conveyor links, and stacking links.

[0036] Step S120: Establish a heat transfer model for the entire process of the casting according to the flow direction and links sorted out above. The model consists of six sub-models: the mathematical model of the roller conveyor process, the mathematical model of the clamp crane conveyor process, the mathematical model of the transverse vehicle conveyor process, the mathematical model of the cross-car conveyor process, the mathematical model of the pallet conveyor process, and the mathematical model of the stacking process. Among them, the mathematical model of the stacking process adopts different boundary conditions for the specific position of the casting in the stack, so as to be closer to the actual situation and make the temperature calculation more accurate.

[0037] In a feasible implementation method, combined with the actual production conditions, the process from flame cutting to entering the heating furnace to cast the billet can be summarized into 8 flows. These 8 summarized flows are in line with the actual production conditions of most companies and have promotion and application value, including: In the qualified flow, without passing through the transverse transfer vehicle, the flow is: flame cutting → roller conveyor → deburring → roller conveyor → numbering → roller conveyor → pallet stacking → clamp crane transport → 1 / 2 span stacking → clamp crane transport → pallet stacking → roller conveyor → heating furnace.

[0038] In the qualified flow, under the condition of passing the transverse transfer vehicle, the flow direction is: flame cutting → roller conveyor → deburring → roller conveyor → numbering → roller conveyor → transverse transfer vehicle → roller conveyor → pallet stacking → clamp crane transport → 1 / 2 span stacking → clamp crane transport → pallet stacking → roller conveyor → heating furnace.

[0039] Under the condition that the flow direction needs to be machine-cleaned and is qualified after machine cleaning, the flow direction is: flame cutting → roller conveyor → deburring → roller conveyor → numbering → roller conveyor → transverse transfer vehicle → flame cleaning → roller conveyor → pallet stacking → 3-span stacking → clamp crane transport → cross-span vehicle transport → 1 / 2-span stacking → clamp crane transport → pallet stacking → roller conveyor → heating furnace.

[0040] If the product needs to be machine cleaned and still fails to meet the standards after machine cleaning, the flow direction is: flame cutting → roller conveyor → deburring → roller conveyor → numbering → roller conveyor → transverse transfer vehicle → flame cleaning → roller conveyor → needs to be cooled to room temperature for manual cleaning.

[0041] The flow direction to be inspected is: flame cutting → roller conveyor → deburring → roller conveyor → numbering → roller conveyor → needs to be cooled to room temperature for manual inspection.

[0042] In the special case flow, under the condition of cross-feeding, that is, 3 / 4 of the caster material is placed in model 2250 and needs to be poured into the corresponding stack, the flow direction is: flame cutting → roller conveyor → deburring → roller conveyor → numbering → roller conveyor → stacking table → clamp crane transport → 1 / 2 span close to 3 / 4 caster stack → clamp crane transport → 1 / 2 span close to 1 / 2 caster stack → clamp crane transport → stacking table → roller conveyor → heating furnace.

[0043] In the special case flow, under the condition of cross-feeding, that is, 1 / 2 of the casting machine material is placed on model 1580 and needs to be poured into the corresponding stack, the flow direction is: flame cutting → roller conveyor → deburring → roller conveyor → numbering → roller conveyor → stacking table → clamp crane transport → 1 / 2 span close to 1 / 2 casting machine stack → clamp crane transport → 1 / 2 span close to 3 / 4 casting machine stack → clamp crane transport → stacking table → roller conveyor → heating furnace.

[0044] In the special flow situation, under the condition of cross-feeding, that is, the material is placed in the 3 / 4 span and needs to be poured to the 1 / 2 span, the flow direction is: flame cutting → roller conveyor → deburring → roller conveyor → numbering → roller conveyor → pallet stacking → clamp crane transport → 3 / 4 span stacking → clamp crane transport → cross-span vehicle transport → 1 / 2 span stacking → clamp crane transport → pallet stacking → roller conveyor → heating furnace.

[0045] It should be noted that the numerical heat transfer method in the process of establishing the heat transfer model of the whole process of casting adopts the finite difference method, and the partial differential equations of the six sub-models are discretized to obtain the discretized equation group about the casting temperature, and then the Gauss-Seidel iteration method is used to solve the discretized equation group.

[0046] The whole process heat transfer model of the casting billet constructed by this method can calculate the casting billet temperature in real time and provide a real-time temperature basis for the scheduling plan.

[0047] Step S200: Calculate the temperature of the casting billet in real time according to the heat transfer model of the entire casting process to obtain the temperature information of the casting billet; Further, step S200 includes: Step S210: obtaining temperature calculation data according to the heat transfer model of the entire casting process, the temperature calculation data including: the first moment and the casting information; Step S220: Calculate the temperature information of the first ingot at the first moment based on the environmental parameters. After the calculation is completed, calculate the temperature information of the next ingot until all the ingot temperature information is calculated. Store the calculation results and calculate the temperature information of the ingot at the next moment until the operator terminates the calculation or the calculation time coincides with the current time.

[0048] Real-time calculation flow chart Figure 4 As shown. First, the calculation starts at the first moment, and the temperature calculation starts from the first billet in the scheduling system. The temperature calculation module calls the corresponding heat transfer model and boundary conditions according to the read parameters to calculate the temperature information. After completing the calculation of one billet, switch to the next billet to continue the calculation, and read the information of the next billet at the same time. Repeat this process until the temperature calculation of the last billet in the scheduling system is completed. Then store the calculation results and enter the calculation of the next second. This process continues until the operator terminates the calculation or the calculation time is consistent with the actual time. Based on the above calculation steps, the temperature of all billets in the scheduling system can be calculated one by one, and the temperature information of each billet at different times can be obtained, and the calculation results can be stored. This process can continue.

[0049] It should be noted that the cut billets maintain high temperature for a considerable period of time, and a large amount of complex heat exchange will be carried out between each other. To ensure the accuracy of the calculation, in the temperature information calculation process, when some billets complete the cutting process and start to be transported, or when the billets are sent to the heating furnace for heating, the corresponding data needs to be transferred from the billet warehouse centralized control system to the temperature calculation module. In this application, the constructed billet full-process heat transfer model can not only calculate the billet temperature in real time, provide real-time temperature basis for the scheduling plan, but also simulate and predict the temperature of the billet in the billet warehouse.

[0050] In addition, the full-process heat transfer model of the billet constructed in this application can obtain the real-time temperature of the billet by calculating the heat transfer model. If the temperature of the billet is calculated to be in the temperature range of the hot delivery defect of the red delivery crack corresponding to this steel grade, it will be reminded that the billet cannot be hot-charged, and the time when the billet meets the hot charging conditions can be predicted by simulation. Based on the calculation of the billet temperature information, the occurrence of red crack quality defects can be greatly reduced by the reminder and prediction method.

[0051] It should be noted that the cut ingots maintain high temperature for a considerable period of time, and a large amount of complex heat exchange takes place between each other. Therefore, in order to ensure the accuracy of the calculation, in the process of temperature information calculation, when some ingots have completed the cutting process and started to be transported, or when the ingots are sent to the heating furnace for heating, the corresponding data needs to be transferred from the ingot warehouse centralized control system to the temperature calculation module to ensure the accuracy of the calculation.

[0052] (twenty three); In formula (23), λ is the thermal conductivity; is the time step; is the spatial step length in the x direction, is the spatial step in the y direction; h is the convection heat transfer coefficient of the left node of the material; C is the specific heat capacity of the material.

[0053] In view of the characteristics of the ingot, this application adopts a two-dimensional orthogonal grid system, utilizes the heat transfer equation of formula (23), and adopts the finite difference method. The relationship between the grid size and time satisfies the stability condition, thereby ensuring that the calculation of the ingot temperature from cutting to entering the heating furnace is stable and convergent.

[0054] The calculation of the temperature of the ingot is stable from the stage after cutting to the stage before entering the heating furnace. Considering the characteristics of the ingot, a two-dimensional orthogonal grid system is used, the heat transfer equation uses the finite difference method, and the relationship between the grid size and time meets the stability condition, so the calculation is stable and convergent.

[0055] In the process of casting and rolling connection embedded in the scheduling plan, the temperature drop calculation method of the ingot is fast. Under the premise of meeting the stability conditions, the number of grids can be minimized to reduce the amount of calculation, and finally the calculation time can be reduced, making the temperature drop calculation method of the ingot embedded in the scheduling plan fast and efficient.

[0056] In addition, the temperature drop calculation method of the billet during the casting and rolling connection process embedded in the scheduling plan is also accurate. Based on the sorted flow directions and links, a full-process heat transfer model for the billet was established. The full-process heat transfer model consists of the following six sub-models: 1. Mathematical model of roller conveyor process; 2. Mathematical model of clamp crane conveyor process; 3. Mathematical model of transverse vehicle conveyor process; 4. Mathematical model of cross-carriage conveyor process; 5. Mathematical model of pallet conveyor process; 6. Mathematical model of stacking process.

[0057] The control equations satisfied by the above six mathematical sub-models are as follows: (twenty four); In formula (24), λ is the thermal conductivity; is the time step; is the spatial step length in the x direction; is the spatial step length in the y direction; h is the convective heat transfer coefficient of the material; is the density of the material; C is the specific heat capacity of the material; ∂ is the partial differential symbol; T is the temperature of the material.

[0058] In terms of boundary condition setting, boundary conditions suitable for model solving are set for each sub-model. Among them, the mathematical model of the stacking process is more specific and accurate in setting boundary conditions. Different boundary conditions are used according to the specific position of the ingot in the stack, which can be closer to the actual situation and make the temperature calculation more accurate. Therefore, the calculation of this model is accurate.

[0059] refer to Figure 5 , Figure 5 It is represented as a calculation flow chart of simulation prediction. The heat transfer model of the whole process of casting constructed by this method can calculate the temperature of the casting in real time, and can also simulate and predict the temperature of the casting in the casting warehouse. The so-called simulation prediction of the temperature of the casting in the casting warehouse refers to the next transportation direction of the casting based on the current temperature information of the casting and the transportation direction of the steel billet summarized and summarized from the field investigation, and then the current temperature information of the casting is set as the initial temperature information, and different heat transfer sub-models are called according to different links in the flow direction for calculation.

[0060] It should be noted that during the rough rolling of microalloyed steel slabs, cracks along the vibration mark direction or in a mesh distribution can be observed on the surface of the coil, which are called red delivery cracks. The red delivery cracks of microalloyed steel slabs are different from the defects of other types of steel slabs. They are a unique defect under hot delivery and hot loading conditions. The depth of the cracks is about 0.3~2.2mm, and the maximum width is about 1.5mm. They are mainly distributed on the entire surface of the steel plate, and are more common at 1 / 2 and 1 / 4 of the width of the steel plate, with a depth of about 0.5~1.5mm. The occurrence of quality defects of red delivery cracks in the slab can be reduced. If the temperature of the slab obtained by calculation is in the temperature range of the hot delivery defect of the red delivery crack corresponding to this steel grade, a reminder window will pop up to remind that the slab cannot be hot loaded at this time, and the time when the slab meets the hot loading conditions can be predicted through simulation prediction. The method of reminder plus prediction can greatly reduce the occurrence of red crack quality defects, thereby reducing a lot of waste of manpower and material resources. The method can be directly applied under existing production conditions, and the transformation cost is low. The temperature drop calculation method of the ingot during the casting and rolling connection process embedded in the scheduling plan has a good effect on improving the hot rolling ingot feeding method.

[0061] Step S300: formulating a hot rolling scheduling plan in real time according to the ingot temperature information and the production order information; Step S400: Scheduling production according to the hot rolling schedule.

[0062] The whole-process heat transfer model of the casting billet constructed by this method can calculate the billet temperature in real time, and obtain the real-time temperature information of each billet, so as to avoid mixing hot and cold billets, thereby reducing the aggravated oxidation and burning of hot billets, reducing the energy consumption of the heating furnace, and improving the metal recovery rate.

[0063] The heat transfer model of the whole process of casting constructed by this method can calculate the temperature of the casting in real time and obtain the real-time temperature information of each casting, so as to avoid mixing hot and cold castings, thereby reducing the aggravation of oxidation and burning of hot castings, reducing the energy consumption of the heating furnace, and improving the metal recovery rate.

[0064] The whole-process heat transfer model of the casting billet constructed by this method can calculate the casting billet temperature in real time, and can calculate the transportation mode that is beneficial to the insulation of the casting billet, thereby improving the heat utilization of the casting billet after cutting and reducing the energy consumption of the heating furnace.

[0065] The whole-process heat transfer model of the casting billet constructed by this method can calculate the casting billet temperature in real time, and can accurately predict through calculation the time required for the hot casting billet temperature to drop to the charging limit temperature for hot delivery and hot charging, that is, the time required under 400°C conditions, thereby improving the hot charging rate.

[0066] The whole-process heat transfer model of the casting billet constructed by this method can calculate the temperature of the casting billet in real time, and can enable the operator to intuitively understand the temperature distribution of the casting billet in the casting billet warehouse, which is convenient for adjusting the casting billet in the warehouse area, thereby promoting the improvement of the hot rolling casting billet feeding method.

[0067] Based on the same inventive concept, the embodiment of the present application also provides a memory management device for implementing the memory management method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more memory management device embodiments provided below can refer to the limitations on the memory management method above, and will not be repeated here.

[0068] According to a second aspect of the present application, a computing device is provided, comprising: Acquisition module, used to establish the heat transfer model of the whole process of billet casting; Calculation module, used for real-time calculation of the temperature of the casting billet; The scheduling module is used to formulate hot rolling scheduling plans and schedule production based on the ingot temperature information and production order information.

[0069] In a third aspect of an embodiment of the present application, a computer device is provided, which may be a device integrating multiple target applications, and the specific implementation process of the memory monitoring module in the target application may be performed by the computer device. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store memory data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a memory management method is implemented.

[0070] According to a third aspect of an embodiment of the present application, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps included in the above-mentioned first aspect when executing the computer program.

[0071] According to a fourth aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps included in the above-mentioned first aspect are implemented.

[0072] According to a fifth aspect of an embodiment of the present application, a computer program product is provided, including a computer program, which, when executed by a processor, implements the steps included in the first aspect.

[0073] Each module in the above memory management device can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0074] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only storage, magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive memory, magnetic memory, ferroelectric memory, phase change memory, graphene memory, etc. Volatile memory may include random access memory or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory or dynamic random access memory, etc. The database involved in the embodiments provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, etc., but is not limited thereto.

[0075] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for calculating the temperature drop of a slab during a casting and rolling connection process embedded in a scheduling plan, characterized in that: include: Step S100: establishing a heat transfer model for the entire casting process; The whole process heat transfer model includes: mathematical model of roller conveyor, mathematical model of clamp crane conveyor, mathematical model of transverse vehicle conveyor, mathematical model of span vehicle conveyor, mathematical model of pallet conveyor and mathematical model of stacking process; Step S110: sorting out the heat transfer links included in the important flow from flame cutting to entering the heating furnace; Step S120: establishing a heat transfer model for the entire casting process according to the heat transfer numerical method, important flow directions and heat transfer links; Step S200: Calculate the temperature of the casting billet in real time according to the heat transfer model of the entire casting process to obtain the temperature information of the casting billet; Step S300: formulating a hot rolling scheduling plan in real time according to the ingot temperature information and the production order information; Step S400: Scheduling production according to the hot rolling schedule.

2. The method for calculating the temperature drop of the slab during the casting and rolling connection process embedded in the scheduling plan according to claim 1 is characterized in that: Step S200 includes: Step S210: obtaining temperature calculation data according to the heat transfer model of the entire casting process, the temperature calculation data including: the first moment, casting information and environmental parameters; Step S220: Calculate the temperature information of the first ingot at the first moment based on the environmental parameters. After the calculation is completed, calculate the temperature information of the next ingot until all the ingot temperature information is calculated. Store the calculation results, and calculate the temperature information of the ingot at the next moment based on the ingot information until the operator terminates the calculation or the calculation time coincides with the current time.

3. The method for calculating the temperature drop of the slab during the casting and rolling connection process embedded in the scheduling plan according to claim 1 is characterized in that: Important flow directions include: qualified flow direction, flow direction requiring machine cleaning, flow direction awaiting inspection and flow direction for special circumstances.

4. The method for calculating the temperature drop of a slab during a casting and rolling connection process embedded in a scheduling plan according to claim 1, characterized in that: The heat transfer links include: roller conveyor transport link, clamp crane transport link, transverse vehicle transport link, cross-car transport link, pallet transport link and stacking link.

5. The method for calculating the temperature drop of the slab during the casting and rolling connection process embedded in the scheduling plan according to claim 4 is characterized in that: The mathematical model of the roller transport process is used to calculate the heat flux density of the upper surface of the ingot, the heat flux density of the lower surface of the ingot and the heat flux density of the side surface of the ingot in the roller transport link.

6. The method for calculating the temperature drop of the slab during the casting and rolling connection process embedded in the scheduling plan according to claim 4 is characterized in that: The mathematical model of the clamp crane transportation process is used to calculate the heat flux density of the upper surface of the ingot, the heat flux density of the lower surface of the ingot and the heat flux density of the side surface of the ingot in the clamp crane transportation link.

7. The method for calculating the temperature drop of the casting billet during the casting and rolling connection process embedded in the scheduling plan according to claim 4 is characterized in that: The mathematical model of the transverse vehicle transportation process is used to calculate the heat flux density of the upper surface of the ingot, the heat flux density of the lower surface of the ingot and the heat flux density of the side surface of the ingot in the transverse vehicle transportation link.

8. The method for calculating the temperature drop of a slab during the casting and rolling connection process embedded in a scheduling plan according to claim 4 is characterized in that: The mathematical model of the straddle carrier transport process is used to calculate the heat flux density of the upper surface, the lower surface and the side surface of the ingot in the straddle carrier transport link.

9. The method for calculating the temperature drop of a slab during the casting and rolling connection process embedded in a scheduling plan according to claim 4, characterized in that: The mathematical model of the pallet transport process is used to calculate the heat flux density of the upper surface of the ingot, the heat flux density of the lower surface of the ingot, the heat flux density of the side surface of the ingot and the heat flux density of the contact surface between adjacent ingots in the pallet transport link.

10. The method for calculating the temperature drop of a slab during the casting and rolling connection process embedded in a scheduling plan according to claim 4, characterized in that: The mathematical model of the stacking process is used to calculate the heat flux density of the upper surface of the billet at the top of the billet stack, the heat flux density of the lower surface of the billet at the top of the billet stack, the heat flux density of the side surface of the billet stack, the heat flux density of the upper surface of the middle billet, the heat flux density of the lower surface of the middle billet, the heat flux density of the upper surface of the billet at the bottom of the billet stack, and the heat flux density of the lower surface of the billet at the bottom of the billet stack.

Images