Lees body steel continuous casting parameter determination method and device, storage medium and continuous casting machine

Abstract

The application discloses a ledeburite steel continuous casting parameter determination method and device, a storage medium and a continuous casting machine, relates to the casting technical field, and mainly aims to solve the problem of high substandard product rate of ledeburite steel continuous casting production. Mainly including determining the cooling rate condition matched with the to-be-cast steel material of the continuous casting machine, the cooling rate condition is determined based on the (Cr, Fe) 7C3 carbide size of the to-be-cast steel material in the hot plasticity test; from the simulation results of the thermal-mechanical coupling model of the continuous casting billet of the continuous casting machine, the mold simulation data of the mold and the secondary cooling area simulation data of the secondary cooling area that meet the cooling rate condition are acquired; the mold control parameters are calculated according to the mold simulation data, and the secondary cooling area control parameters are calculated according to the secondary cooling area simulation data; the mold control parameters and the secondary cooling area control parameters are sent to the control end of the continuous casting machine, so that the continuous casting machine carries out continuous casting production on the to-be-cast steel material according to the mold control parameters and the secondary cooling area control parameters. The main user ledeburite steel continuous casting parameter determination production.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and in particular to a method, apparatus, storage medium, and continuous casting machine for determining continuous casting parameters of ledeburitic steel. Background Technology

[0002] Continuous casting, also known as continuous steel casting, involves the continuous passage of molten steel through a water-cooled crystallizer. After solidifying into a hard shell, the steel is continuously pulled out from the bottom outlet of the crystallizer, cooled by water spray, and finally cut into billets after complete solidification. Compared to traditional ingot casting, continuous casting offers better metal yield and billet quality, and also has significant advantages in energy conservation. Ledeburitic steel, a high-carbon, high-chromium steel suitable for continuous casting, is widely used in cold-working dies and is suitable for manufacturing various dies with complex shapes and under heavy working conditions.

[0003] Currently, the process of determining the continuous casting parameters for ledeburitic steel mainly relies on operators configuring the parameters of the continuous casting machine based on their experience. However, due to the high carbon content of ledeburitic steel, its liquidus temperature is more than 100°C lower than that of ordinary low-carbon steel, making it difficult to melt the protective slag. In addition, its thermal shrinkage coefficient is low and the shrinkage of the solidified billet shell is small. During the production process, it is easy for the protective slag to have difficulty flowing into the channel between the billet and the crystallizer, resulting in reduced protective slag consumption, increased friction, and easy formation of depressions on the surface of the produced continuous casting billet, which in turn induces quality problems such as longitudinal cracks and steel leakage. Summary of the Invention

[0004] In view of this, the present invention provides a method, apparatus, storage medium and continuous casting machine for determining continuous casting parameters of ledeburitic steel, the main purpose of which is to solve the problem of high defect rate in existing continuous casting production of ledeburitic steel.

[0005] According to one aspect of the present invention, a method for determining continuous casting parameters of ledeburitic steel is provided, comprising:

[0006] The cooling rate conditions matching the steel to be cast in the continuous casting machine are determined, and the cooling rate conditions are determined based on the target carbide size of the steel to be cast in the thermoplasticity test.

[0007] From the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine, obtain the simulation data of the crystallizer and the simulation data of the secondary cooling zone that meet the cooling rate conditions;

[0008] The crystallizer control parameters are calculated based on the crystallizer simulation data, and the secondary cooling zone control parameters are calculated based on the secondary cooling zone simulation data.

[0009] The crystallizer control parameters and the secondary cooling zone control parameters are sent to the control terminal of the continuous casting machine so that the continuous casting machine can continuously cast the steel to be cast in accordance with the crystallizer control parameters and the secondary cooling zone control parameters.

[0010] Furthermore, the crystallizer simulation data includes crystallizer superheat, dummy bar pulling speed, and crescent surface heat flux density. The crystallizer control parameters calculated based on the crystallizer simulation data include:

[0011] Obtain the cooling water temperature, ambient temperature, and associated dimensionless parameters of the continuous casting machine;

[0012] Based on the lunar surface heat flux density, the cooling water temperature, the ambient temperature, the dimensionless parameters, and the heat flux density-water volume conversion relationship, the water distribution of the crystallizer is calculated.

[0013] The crystallizer control parameters are generated based on the crystallizer water supply, the crystallizer superheat, and the siphon bar pulling speed.

[0014] Furthermore, the simulation data for the secondary cooling zone includes the nodal surface heat flux density of each cooling zone segment in the secondary cooling region, and the control parameters for the secondary cooling zone calculated based on the simulation data include:

[0015] For each cooling zone, the water flow density is calculated based on the heat flux density of the node surface, the cooling water temperature, and the associated dimensionless parameters.

[0016] The control parameters for the secondary cooling zone are generated based on the water flow density of each cooling zone.

[0017] Furthermore, before obtaining the crystallizer simulation data and secondary cooling zone simulation data that satisfy the cooling rate condition from the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine, the method further includes:

[0018] Based on the billet size parameters of the continuous casting machine, a gridded billet structure model is constructed with the meniscus position in the crystallizer as the body center plane;

[0019] The gridded billet structure model is subjected to thermo-mechanical coupling simulation based on preset thermo-mechanical coupling parameters, and the simulation results are obtained from the thermo-mechanical coupling model of the continuous casting machine billet.

[0020] Furthermore, the simulation results of the thermo-mechanical coupling model of the continuously cast billet from the gridded billet structure model based on preset thermo-mechanical coupling parameters to the thermo-mechanical coupling model of the continuously cast billet of the continuous casting machine include:

[0021] Configure the thermo-mechanical coupling state of the structure above the center plane of the gridded billet structure model as the initial state;

[0022] Based on the thermo-coupling parameters, configure the superheat boundary conditions, superheat variation range, dummy bar pulling speed boundary conditions, and dummy bar pulling speed variation range of the structure below the body center plane of the gridded billet structure model;

[0023] The semi-cast billet structural model with the thermo-mechanical coupling parameters configured was simulated and the simulation results of the continuous casting billet thermo-mechanical coupling model were obtained.

[0024] Furthermore, the step of constructing a gridded billet structure model based on the billet size parameters of the continuous casting machine, with the meniscus position in the crystallizer as the body center plane, includes:

[0025] Obtain the structural symmetry direction of the continuously casting machine billet;

[0026] Based on the dimensional parameters in the symmetrical direction of the structure, a three-dimensional structural model of the semi-cast billet is constructed with the meniscus position in the crystallizer as the body center plane;

[0027] The three-dimensional structural model of the semi-cast billet is subjected to non-uniform mesh generation to obtain a meshed billet structural model.

[0028] Furthermore, before determining the cooling rate conditions matching the steel to be cast in the continuous casting machine, the method further includes:

[0029] High-temperature confocal in-situ observation results were collected during the thermoplasticity test of samples of different cast steels.

[0030] Extracting the surface cooling rate of the (Cr,Fe)7C3 carbide with a size of less than 10 μm from the high-temperature confocal in-situ observation results;

[0031] The cooling rate conditions of the cast steel are configured according to the surface cooling rate, and a mapping relationship between the material parameters of the cast steel and the cooling rate conditions is constructed.

[0032] According to another aspect of the present invention, a device for determining continuous casting parameters of ledeburitic steel is provided, comprising:

[0033] A determination module is used to determine the cooling rate conditions that match the steel to be cast in the continuous casting machine, the cooling rate conditions being determined based on the target carbide size of the steel to be cast in the thermoplasticity test;

[0034] The acquisition module is used to acquire, from the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine, the simulation data of the crystallizer and the simulation data of the secondary cooling zone that meet the cooling rate conditions.

[0035] The calculation module is used to calculate the crystallizer control parameters based on the crystallizer simulation data, and to calculate the secondary cooling zone control parameters based on the secondary cooling zone simulation data.

[0036] The sending module is used to send the crystallizer control parameters and the secondary cooling zone control parameters to the control terminal of the continuous casting machine, so that the continuous casting machine can continuously cast the steel to be cast in accordance with the crystallizer control parameters and the secondary cooling zone control parameters.

[0037] Furthermore, the computing module includes:

[0038] The first acquisition unit is used to acquire the cooling water temperature, ambient temperature, and associated dimensionless parameters of the continuous casting machine.

[0039] The first calculation unit is used to calculate the water distribution of the crystallizer based on the heat flux density of the crescent surface, the cooling water temperature, the ambient temperature, the dimensionless parameters, and the heat flux density-water volume conversion relationship.

[0040] The first generation unit is used to generate crystallizer control parameters based on the crystallizer water supply, the crystallizer superheat, and the derrick pulling speed.

[0041] Furthermore, the computing module also includes:

[0042] The second calculation unit is used to calculate the water flow density for each cooling zone based on the heat flux density of the node surface, the cooling water temperature, and the associated dimensionless parameters.

[0043] The second generation unit is used to generate control parameters for the secondary cooling zone based on the water flow density of each cooling zone.

[0044] Furthermore, the device also includes:

[0045] The construction module is used to construct a gridded billet structure model based on the billet size parameters of the continuous casting machine, with the meniscus position in the crystallizer as the body center plane;

[0046] The simulation module is used to perform thermo-mechanical coupling simulation of the gridded billet structure model based on preset thermo-mechanical coupling parameters, and to obtain the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine.

[0047] Furthermore, the simulation module includes:

[0048] The first configuration unit is used to configure the thermo-mechanical coupling state of the structure above the center plane of the gridded billet structure model as the initial state.

[0049] The second configuration unit is used to configure the superheat boundary conditions, superheat variation range, dummy bar pulling speed boundary conditions, and dummy bar pulling speed variation range of the structure below the body center plane of the gridded billet structure model according to the thermo-coupling parameters.

[0050] The simulation unit is used to simulate the semi-cast billet structure model with the thermo-mechanical coupling parameters configured, and to obtain the simulation results of the continuous casting billet thermo-mechanical coupling model.

[0051] Furthermore, the building module includes:

[0052] The second acquisition unit is used to acquire the structural symmetry direction of the continuous casting machine billet;

[0053] A framework unit is used to construct a three-dimensional structural model of a semi-cast billet based on the dimensional parameters in the symmetrical direction of the structure, with the meniscus position in the crystallizer as the body center plane.

[0054] Mesh generation units are used to perform non-uniform mesh generation on the three-dimensional structural model of the semi-cast billet to obtain a meshed billet structural model.

[0055] Furthermore, the device also includes:

[0056] The acquisition module is also used to acquire high-temperature confocal in-situ observation results of samples of different cast steels during the thermoplasticity test.

[0057] The extraction module is used to extract the surface cooling rate of (Cr,Fe)7C3 carbides with a size of less than 10 μm in the high-temperature confocal in-situ observation results.

[0058] The configuration module is used to configure the cooling rate conditions of the cast steel according to the surface cooling rate, and to construct a mapping relationship between the material parameters of the cast steel and the cooling rate conditions.

[0059] According to another aspect of the present invention, a storage medium is provided, wherein at least one executable instruction is stored therein, the executable instruction causing a processor to perform an operation corresponding to the above-described method for determining continuous casting parameters of ledeburitic steel.

[0060] According to another aspect of the present invention, a continuous casting machine is provided, which is manufactured based on parameters determined by the method for determining continuous casting parameters of ledeburitic steel as described in any one of claims 1-7.

[0061] By employing the above-described technical solutions, the technical solutions provided by the embodiments of the present invention have at least the following advantages:

[0062] This invention provides a method, apparatus, storage medium, and continuous casting machine for determining continuous casting parameters of ledeburitic steel. In this embodiment, the cooling rate conditions matching the steel to be cast are determined based on the target carbide size of the steel in a thermoplasticity test. Simulation data of the crystallizer and the secondary cooling zone satisfying the cooling rate conditions are obtained from the simulation results of the thermo-mechanical coupling model of the continuous casting billet. Crystallizer control parameters are calculated based on the crystallizer simulation data, and secondary cooling zone control parameters are calculated based on the secondary cooling zone simulation data. These parameters are then sent to the control terminal of the continuous casting machine, enabling the machine to continuously cast the steel according to these parameters. This significantly improves the accuracy of cooling zone water volume control, avoids the uncertainty of equipment adjustment based on manual experience, and ensures the accuracy of water volume control, reducing the possibility of cooling quality issues and effectively lowering the defect rate of the continuous casting output.

[0063] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0064] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0065] Figure 1 A flowchart of a method for determining continuous casting parameters of ledeburitic steel according to an embodiment of the present invention is shown;

[0066] Figure 2 This invention provides a schematic diagram of the continuous casting process of a continuous casting machine according to an embodiment of the present invention.

[0067] Figure 3 A flowchart of another method for determining continuous casting parameters of ledeburitic steel provided by an embodiment of the present invention is shown;

[0068] Figure 4 This diagram illustrates a solidification process of a continuously cast billet according to an embodiment of the present invention.

[0069] Figure 5 A schematic diagram of a continuous casting billet model provided in an embodiment of the present invention is shown;

[0070] Figure 6 A block diagram of a continuous casting parameter determination device for ledeburitic steel provided in an embodiment of the present invention is shown. Detailed Implementation

[0071] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0072] To address the high defect rate in existing continuous casting production of ledeburitic steel, this invention provides a method for determining continuous casting parameters for ledeburitic steel, such as... Figure 1 As shown, the method includes:

[0073] 101. Determine the cooling rate conditions that match the steel to be cast in the continuous casting machine.

[0074] In this embodiment of the invention, the continuous casting machine is a continuous casting execution device that requires determining the continuous casting parameters of ledeburitic steel. For example, such as Figure 2 The continuous casting machine shown mainly consists of a tundish, a crystallizer, a secondary cooling channel, a dummy bar, and a straightening machine. During continuous casting, the molten steel in the tundish enters the crystallizer through the nozzle. In the crystallizer, the molten steel is rapidly solidified under strong cooling to form a billet shell, which is then pulled out at a certain speed by the dummy bar. It continues to cool in the secondary cooling zone and air cooling zone until it is completely solidified at the solidification endpoint, completing the conversion from molten steel to a cast billet at the end of the casting machine. During continuous casting, the cooling process of the cast billet involves the precipitation of carbides at the austenite grain boundaries, which coarsens as the billet cools. It also involves the precipitation of high-hardness compounds that cause cracks in the billet. Therefore, the cooling rate is a key factor affecting the quality of the output. The steel to be cast can be any existing ledeburitic steel, such as Cr12 die steel, Cr12MoV alloy tool steel, or Cr12W wear-resistant cold work die steel. Different ledeburitic steels with different material parameters require different cooling rates (cooling speeds). Therefore, it is necessary to determine the cooling rate conditions that match the steel to be cast.

[0075] It should be noted that the cooling rate conditions are determined based on the size of the (Cr,Fe)7C3 carbides in the thermoplasticity test of the steel to be cast. Since the size and distribution of (Cr,Fe)7C3 carbides are crucial to improving the quality of the cast billet during continuous casting, thermoplasticity tests are conducted on the cast steel beforehand to determine the optimal surface cooling rate conditions for different cast steels. These optimal cooling rate conditions are then used as the cooling control targets for the crystallizer and secondary cooling zone of the continuous casting machine, thereby inversely determining the continuous casting production parameters.

[0076] 102. From the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine, obtain the simulation data of the crystallizer and the simulation data of the secondary cooling zone that meet the cooling rate conditions.

[0077] In this embodiment of the invention, after determining the cooling rate conditions, in order to determine accurate continuous casting parameters, a three-dimensional model is pre-constructed based on the current equipment parameters of the continuous casting machine. A thermo-mechanical coupling simulation of the continuous casting process is then performed on the steel to be cast, obtaining simulation data under different cooling rates. From the simulation results, simulation data of the crystallizer and the secondary cooling zone that meet the cooling rate conditions are then selected. The model construction can be based on the finite element software MSC.MARC as the simulation platform for three-dimensional modeling, or it can be based on other finite element software; this embodiment of the invention does not impose specific limitations. By constructing a three-dimensional model of the continuous casting machine and simulating the continuous casting process, on-site debugging of the continuous casting machine can be avoided. While ensuring the accuracy of the continuous casting process data, the efficiency of data determination is greatly improved, and equipment debugging costs are reduced.

[0078] 103. The crystallizer control parameters are calculated based on the crystallizer simulation data, and the secondary cooling zone control parameters are calculated based on the secondary cooling zone simulation data.

[0079] In this embodiment of the invention, the simulation data includes equipment operation data and steel performance data of the continuous casting process, such as crystallizer superheat, dummy bar pulling speed, and steel heat flux density. Since some of these data are equipment operation control parameters, such as dummy bar pulling speed, and others are outcome data, such as steel heat flux density, for outcome data, it is necessary to deduce the equipment control parameters based on the results. For example, the cooling water distribution rate of the crystallizer is a major factor affecting the heat flux density of the crystallizer meniscus. A formula relating the water distribution rate and the meniscus heat flux density can be derived from historical production data, and the water distribution rate can be calculated based on this formula and the meniscus heat flux density in the simulation data. As another example, the water flux density of each cooling section within the secondary cooling zone can be calculated based on the heat flux density of each cooling section and the formula relating heat flux density to water flux density.

[0080] 104. Send the crystallizer control parameters and the secondary cooling zone control parameters to the control terminal of the continuous casting machine so that the continuous casting machine can continuously cast the steel to be cast in accordance with the crystallizer control parameters and the secondary cooling zone control parameters.

[0081] In this embodiment of the invention, after determining the crystallizer control parameters and the secondary cooling zone control parameters, these parameters are sent to the control terminal of the continuous casting machine. This allows the continuous casting machine control terminal to configure the corresponding parameters to the corresponding cooling execution terminals. During the continuous casting production of the steel to be cast, continuous casting production is executed according to the crystallizer control parameters and the secondary cooling zone control parameters. The control terminal can be an industrial control computer or a control device corresponding to different execution terminals, such as a programmable logic controller (PLC). This embodiment of the invention does not impose specific limitations.

[0082] It should be noted that by conducting thermoplasticity tests on the steel to be cast, the optimal cooling rate conditions were determined based on the key factors affecting the quality of the continuously cast billet (the size of the (Cr,Fe)7C3 carbides). Production data under the cooling rate conditions were simulated based on the three-dimensional model of the continuous casting machine. Then, the control parameters of the continuous casting machine were derived from the production data, which improved the reliability of the control parameter configuration and greatly increased the accuracy of the control parameters. At the same time, it greatly reduced the commissioning time of the continuous casting machine, thereby ensuring the production quality of ledeburitic steel continuous casting and reducing the defect rate.

[0083] In another embodiment of the invention, for further explanation and limitation, such as Figure 3 As shown, step 103, which involves calculating the crystallizer control parameters based on the crystallizer simulation data, includes:

[0084] 201. Obtain the cooling water temperature, ambient temperature, and related dimensionless parameters of the continuous casting machine.

[0085] 202. Based on the lunar surface heat flux density, the cooling water temperature, the ambient temperature, the dimensionless parameters, and the heat flux density-water volume conversion relationship, the water distribution of the crystallizer is calculated.

[0086] 203. Based on the water supply to the crystallizer, the superheat of the crystallizer, and the pulling speed of the siphon rod, generate crystallizer control parameters.

[0087] In this embodiment of the invention, the crystallizer simulation data includes crystallizer superheat, dummy bar speed, and crescent heat flux density. These simulation parameters can be extracted from the simulation results of the continuous casting billet thermo-mechanical coupling model. The dummy bar speed and crescent heat flux density are set as W, the ambient temperature as T0, and the cooling water temperature as T. w The water flow rate to the crystallizer is L. The conversion formula between the water flow rate to the crescent surface heat flux density is as follows:

[0088]

[0089] Among them, C m T is a dimensionless constant related to the equipment parameters of the continuous casting machine, typically taken as [4,5], such as 4.183; w The temperature difference value of -T0 can be calculated based on the ambient temperature and cooling water temperature collected by the on-site temperature sensor, or it can be determined based on experience. The ambient temperature is ℃, and the temperature difference is taken in the range of 5.5℃-8℃, such as 6℃. S is the contact surface area between the crystallizer and the water supply, which can be calculated based on the equipment parameters of the continuous casting machine. The water supply volume of the crystallizer can be calculated according to formula (1). By using the conversion relationship between the water supply volume of the crystallizer and the heat flux density of the crescent surface, the water supply volume of the crystallizer can be deduced from the heat flux density of the crescent surface obtained by simulation. The cooling water supply volume of the crystallizer can be accurately calculated, thereby realizing the precise control of the cooling temperature and cooling rate of the crystallizer section, which greatly reduces the possibility of quality problems in the continuous casting billet during the cooling stage of the crystallizer and greatly reduces the defect rate of the continuous casting billet.

[0090] In another embodiment of the invention, for further explanation and limitation, the step of calculating the control parameters of the two cooling zones based on the simulation data of the two cooling zones includes:

[0091] For each cooling zone, the water flow density is calculated based on the heat flux density of the node surface, the cooling water temperature, and the associated dimensionless parameters.

[0092] The control parameters for the secondary cooling zone are generated based on the water flow density of each cooling zone.

[0093] In this embodiment of the invention, the simulation data for the secondary cooling zone includes the nodal surface heat flux density of each cooling zone segment within the secondary cooling zone. That is, the secondary cooling zone typically includes 8 to 10 cooling zones, and the nodal surface heat flux density of any given cooling zone can be extracted from the simulation results. Let W be the nodal surface heat flux density of any given cooling zone within the secondary cooling zone. i The formula for calculating the water flow density ρ in this cooling zone is:

[0094]

[0095] The water flow density of any section of the secondary cooling zone can be calculated using the above formula, thereby enabling accurate control of the cooling rate in the secondary cooling zone. This significantly reduces the possibility of quality problems in the continuous casting billet during the secondary cooling stage and greatly reduces the defect rate of the continuous casting billet.

[0096] In another embodiment of the invention, for further explanation and limitation, before obtaining the crystallizer simulation data and secondary cooling zone simulation data satisfying the cooling rate condition from the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine, the method further includes:

[0097] Based on the billet size parameters of the continuous casting machine, a gridded billet structure model is constructed with the meniscus position in the crystallizer as the body center plane;

[0098] The gridded billet structure model is subjected to thermo-mechanical coupling simulation based on preset thermo-mechanical coupling parameters, and the simulation results are obtained from the thermo-mechanical coupling model of the continuous casting machine billet.

[0099] In this embodiment of the invention, a thermo-mechanical coupling model of the entire continuous casting process is established using the finite element software MSC.Marc. This model is constructed considering the temperature load and static pressure of the molten steel during the continuous casting process. Figure 4 The diagram shows a schematic of the solidification of a continuously cast billet. The X-axis represents the thickness of the billet, the Z-axis represents the width of the billet, and the negative Y-axis represents the casting direction. The unit layer within the XOZ plane represents the meniscus position in the crystallizer, and the YOZ plane represents the symmetry plane in the width direction. To improve simulation accuracy, a non-uniform meshing technique is used to divide the continuously cast billet into tetrahedral meshes. The unit side length can be 15mm, or it can be customized according to actual application requirements; this embodiment of the invention does not impose specific limitations. Since the calculation error increases when the mesh is dense in the middle and sparse at the edges, the mesh near the edges is configured to be finer, while the mesh in the middle is configured to be relatively sparse. This allows for a more accurate depiction of the changes in variables using a denser mesh, thereby effectively improving calculation accuracy.

[0100] In another embodiment of the invention, for further explanation and limitation, the step of performing thermo-mechanical coupling simulation of the gridded billet structure model based on preset thermo-mechanical coupling parameters, and the simulation results of the thermo-mechanical coupling model of the continuous casting machine billet, include:

[0101] Configure the thermo-mechanical coupling state of the structure above the center plane of the gridded billet structure model as the initial state;

[0102] Based on the thermo-coupling parameters, configure the superheat boundary conditions, superheat variation range, dummy bar pulling speed boundary conditions, and dummy bar pulling speed variation range of the structure below the body center plane of the gridded billet structure model;

[0103] The semi-cast billet structural model with the thermo-mechanical coupling parameters configured was simulated and the simulation results of the continuous casting billet thermo-mechanical coupling model were obtained.

[0104] In this embodiment of the invention, to prevent the continuous casting billet units already in the crystallizer from affecting the temperature and structural deformation of the continuous casting billet units not in the crystallizer during the cooling and deformation process, the MARC secondary development technology is used to maintain the initial state of the continuous casting billet units above the meniscus. The thermo-mechanical coupling process only occurs when the units are below the meniscus. That is, superheat boundary conditions, superheat variation range, dummy bar casting speed boundary conditions, and dummy bar casting speed variation range are configured only for the continuous casting billet structure below the meniscus. Specifically, the superheat boundary conditions can be a lower boundary of 20°C, an upper boundary of 30°C, and a superheat variation range of 2°C. The casting speed boundary conditions can be an upper boundary of 1.1 m / min, a lower boundary of 0.6 m / min, and a casting speed variation range of 0.1 m / min. Of course, the superheat boundary conditions, superheat variation range, dummy bar casting speed boundary conditions, and dummy bar casting speed variation range can also be customized according to actual application requirements; this embodiment of the invention does not impose specific limitations. During the simulation, by adjusting the casting speed and superheat, multiple sets of continuous casting billet surface temperatures, average cooling rates, and heat flux densities can be obtained. In this process, the influence of mold vibration on heat transfer is ignored; the effect of molten steel flow in the mold on the coupling process is also disregarded.

[0105] In another embodiment of the invention, for further explanation and definition, the step, based on the billet size parameters of the continuous casting machine, constructs a gridded billet structure model with the meniscus position in the crystallizer as the body center plane, including:

[0106] Obtain the structural symmetry direction of the continuously casting machine billet;

[0107] Based on the dimensional parameters in the symmetrical direction of the structure, a three-dimensional structural model of the semi-cast billet is constructed with the meniscus position in the crystallizer as the body center plane;

[0108] The three-dimensional structural model of the semi-cast billet is subjected to non-uniform mesh generation to obtain a meshed billet structural model.

[0109] In this embodiment of the invention, the structural symmetry direction of the continuously cast billet is generally the width direction, meaning the billet exhibits symmetry along its width. Modeling a complete continuously cast billet would be computationally expensive. Due to this symmetry, half of the billet's width is selected for modeling, thus saving computational costs. Because the billet model has a limited length and there is a biting effect at the billet head, the beginning and end positions of the billet do not reflect the actual deformation of the billet when in contact with the casting roll. Therefore, a mid-surface is set in the model at the middle position of the billet's casting direction. For example... Figure 5The model shown is a continuous casting billet model. The dimensions of the continuous casting billet are 200mm×100mm×3000mm (width direction×thickness direction×drawing direction). The length of the billet in the model is 3000mm. The middle surface is far enough away from the beginning and end of the billet that the biting effect has little impact on this position. The middle surface position can better reflect the actual deformation of the billet.

[0110] In another embodiment of the invention, for further explanation and limitation, before determining the cooling rate conditions matching the steel to be cast in the continuous casting machine, the method further includes:

[0111] High-temperature confocal in-situ observation results were collected during the thermoplasticity test of samples of different cast steels.

[0112] Extracting the surface cooling rate of the (Cr,Fe)7C3 carbide with a size of less than 10 μm from the high-temperature confocal in-situ observation results;

[0113] The cooling rate conditions of the cast steel are configured according to the surface cooling rate, and a mapping relationship between the material parameters of the cast steel and the cooling rate conditions is constructed.

[0114] In this embodiment of the invention, to determine the accurate cooling rate conditions, different cast steels expected to undergo continuous casting production are selected and prepared into thermoplasticity test samples. The specific process for thermoplasticity testing of any type of continuously cast steel includes: taking a sample at 1 / 4 of the distance from the bottom surface of the billet, avoiding the central region where central segregation and shrinkage porosity are severe. The sample is wire-cut into small cylinders (e.g., 4 mm in diameter and 1.5 mm in height). The surface of the small cylinder is routinely ground and polished to keep the test surface smooth. The polished sample is placed in an alumina crucible and then placed in a PT sample holder with an R-type thermocouple. After evacuating the furnace chamber with a vacuum pump to avoid oxidation of the sample surface, argon gas is continuously blown into the furnace chamber. A laser beam heats the upper surface of the sample at a rate of 15 kHz. All samples are heated to 200°C at a rate of 0.8°C / s, and then heated to 1450°C at a rate of 5°C / s, held for 5 minutes to allow them to fully melt. The samples were then cooled to 700℃ at cooling rates of 0.2℃ / s, 3℃ / s, 5℃ / s, and 7℃ / s, respectively, followed by quenching. During this process, in-situ observation and metallographic analysis of the solidification of ledeburitic steel were performed using a high-temperature confocal microscopy system. The cooling rate for (Cr,Fe)7C3 with a size less than 10μm was determined, and cooling rate conditions were established based on this rate. For example, the range of ±0.1℃ from this cooling rate was defined as the cooling rate condition. To enable rapid matching of corresponding cooling rate conditions to different casting steels, a mapping relationship between different casting steels and the tested cooling rate conditions was established. This allows for the determination of the corresponding cooling rate conditions based on the steel to be cast before actual production on the continuous casting machine.

[0115] This invention provides a method for determining continuous casting parameters for ledeburitic steel. In this embodiment, the cooling rate conditions matching the steel to be cast in the continuous casting machine are determined, based on the target carbide size of the steel in the thermoplasticity test. Simulation data of the crystallizer and the secondary cooling zone that satisfy the cooling rate conditions are obtained from the simulation results of the thermo-mechanical coupling model of the continuous casting billet. Crystallizer control parameters are calculated based on the crystallizer simulation data, and secondary cooling zone control parameters are calculated based on the secondary cooling zone simulation data. These crystallizer and secondary cooling zone control parameters are sent to the control terminal of the continuous casting machine, enabling the continuous casting machine to continuously cast the steel according to these parameters. This significantly improves the accuracy of cooling zone water volume control, avoids the uncertainty of equipment adjustment based on manual experience, and ensures the accuracy of water volume control in the continuous casting machine, reducing the possibility of cooling quality temperature issues and effectively reducing the defect rate of the continuous casting output.

[0116] Furthermore, as a response to the above Figure 1The implementation of the method shown in this embodiment of the invention provides a device for determining continuous casting parameters of ledeburitic steel, such as... Figure 6 As shown, the device includes:

[0117] The determination module 31 is used to determine the cooling rate conditions that match the steel to be cast in the continuous casting machine, the cooling rate conditions being determined based on the target carbide size of the steel to be cast in the thermoplasticity test.

[0118] The acquisition module 32 is used to acquire, from the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine, the crystallizer simulation data and the secondary cooling zone simulation data that meet the cooling rate conditions;

[0119] The calculation module 33 is used to calculate the crystallizer control parameters based on the crystallizer simulation data, and to calculate the secondary cooling zone control parameters based on the secondary cooling zone simulation data.

[0120] The sending module 34 is used to send the crystallizer control parameters and the secondary cooling zone control parameters to the control terminal of the continuous casting machine, so that the continuous casting machine can continuously cast the steel to be cast in accordance with the crystallizer control parameters and the secondary cooling zone control parameters.

[0121] Furthermore, the computing module includes:

[0122] The first acquisition unit is used to acquire the cooling water temperature, ambient temperature, and associated dimensionless parameters of the continuous casting machine.

[0123] The first calculation unit is used to calculate the water distribution of the crystallizer based on the heat flux density of the crescent surface, the cooling water temperature, the ambient temperature, the dimensionless parameters, and the heat flux density-water volume conversion relationship.

[0124] The first generation unit is used to generate crystallizer control parameters based on the crystallizer water supply, the crystallizer superheat, and the derrick pulling speed.

[0125] Furthermore, the computing module also includes:

[0126] The second calculation unit is used to calculate the water flow density for each cooling zone based on the heat flux density of the node surface, the cooling water temperature, and the associated dimensionless parameters.

[0127] The second generation unit is used to generate control parameters for the secondary cooling zone based on the water flow density of each cooling zone.

[0128] Furthermore, the device also includes:

[0129] The construction module is used to construct a gridded billet structure model based on the billet size parameters of the continuous casting machine, with the meniscus position in the crystallizer as the body center plane;

[0130] The simulation module is used to perform thermo-mechanical coupling simulation of the gridded billet structure model based on preset thermo-mechanical coupling parameters, and to obtain the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine.

[0131] Furthermore, the simulation module includes:

[0132] The first configuration unit is used to configure the thermo-mechanical coupling state of the structure above the center plane of the gridded billet structure model as the initial state.

[0133] The second configuration unit is used to configure the superheat boundary conditions, superheat variation range, dummy bar pulling speed boundary conditions, and dummy bar pulling speed variation range of the structure below the body center plane of the gridded billet structure model according to the thermo-coupling parameters.

[0134] The simulation unit is used to simulate the semi-cast billet structure model with the thermo-mechanical coupling parameters configured, and to obtain the simulation results of the continuous casting billet thermo-mechanical coupling model.

[0135] Furthermore, the building module includes:

[0136] The second acquisition unit is used to acquire the structural symmetry direction of the continuous casting machine billet;

[0137] A framework unit is used to construct a three-dimensional structural model of a semi-cast billet based on the dimensional parameters in the symmetrical direction of the structure, with the meniscus position in the crystallizer as the body center plane.

[0138] Mesh generation units are used to perform non-uniform mesh generation on the three-dimensional structural model of the semi-cast billet to obtain a meshed billet structural model.

[0139] Furthermore, the device also includes:

[0140] The acquisition module is also used to acquire high-temperature confocal in-situ observation results of samples of different cast steels during the thermoplasticity test.

[0141] The extraction module is used to extract the surface cooling rate of the (Cr,Fe)7C3 carbide with a size of less than 10 μm in the high-temperature confocal in-situ observation results.

[0142] The configuration module is used to configure the cooling rate conditions of the cast steel according to the surface cooling rate, and to construct a mapping relationship between the material parameters of the cast steel and the cooling rate conditions.

[0143] This invention provides a device for determining continuous casting parameters of ledeburitic steel. In this embodiment, the device determines cooling rate conditions that match the steel to be cast in the continuous casting machine. These cooling rate conditions are based on the target carbide size of the steel in the thermoplasticity test. Simulation data of the crystallizer and the secondary cooling zone that satisfy the cooling rate conditions are obtained from the simulation results of the thermo-mechanical coupling model of the continuous casting billet. Crystallizer control parameters are calculated based on the crystallizer simulation data, and secondary cooling zone control parameters are calculated based on the secondary cooling zone simulation data. These crystallizer and secondary cooling zone control parameters are sent to the control terminal of the continuous casting machine, enabling the continuous casting machine to continuously cast the steel according to these parameters. This significantly improves the accuracy of cooling zone water volume control, avoids the uncertainty of equipment adjustment based on manual experience, and ensures the accuracy of water volume control in the continuous casting machine, reducing the possibility of cooling quality temperature issues and effectively reducing the defect rate of the continuous casting output.

[0144] According to one embodiment of the present invention, a storage medium is provided, the storage medium storing at least one executable instruction, the computer-executable instruction being able to execute the method for determining continuous casting parameters of ledeburitic steel in any of the above method embodiments.

[0145] According to one embodiment of the present invention, a continuous casting machine is provided, which is manufactured based on parameters determined by the method for determining continuous casting parameters of ledeburitic steel as described in any one of claims 1-7.

[0146] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0147] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of determining continuous casting parameters for a ledeburite steel, characterized in that, The method comprises the following steps: determining a cooling rate condition matched with the steel material to be cast by the continuous casting machine, the cooling rate condition being determined based on a target carbide size of the steel material to be cast in a hot ductility test; From the simulation results of the continuous casting billet thermal-mechanical coupling model of the continuous caster, mold simulation data and secondary cooling zone simulation data satisfying the cooling rate condition are acquired, wherein the mold simulation data includes mold superheat, dummy bar pulling speed and meniscus heat flux density , and the secondary cooling zone simulation data includes node surface heat flux density of each section cooling zone in the secondary cooling region . calculating a mold control parameter according to the mold simulation data and a secondary cooling zone control parameter according to the secondary cooling zone simulation data; The mold control parameter calculated according to the mold simulation data comprises: obtaining cooling water temperature of the continuous casting machine , ambient temperature and associated dimensionless parameter ; calculating mold water distribution S according to meniscus heat flux density , the cooling water temperature , the ambient temperature , the associated dimensionless parameter and heat flux density-water conversion relationship, wherein the conversion relationship formula of the mold water distribution S and the meniscus heat flux density is: ; generating the mold control parameter according to the mold water distribution S, the mold superheat and the dummy bar pulling speed; The calculation of the secondary cooling zone control parameters according to the secondary cooling zone simulation data comprises: for each cooling zone, the water flow density is calculated according to the node surface heat flux density , the cooling water temperature , the correlation dimensionless parameter . The formula of the water flow density is as follows: The secondary cooling zone control parameters are generated according to the water flow density of each cooling zone. sending the mold control parameter and the secondary cooling zone control parameter to a control end of the continuous casting machine, so that the continuous casting machine casts the steel material to be cast according to the mold control parameter and the secondary cooling zone control parameter.

2. The method of claim 1, wherein, Before the step of obtaining the mold simulation data and the secondary cooling zone simulation data satisfying the cooling rate condition from the simulation result of the continuous casting billet thermomechanical coupling model of the continuous casting machine, the method further comprises: constructing a grid-based billet structure model with a meniscus position in the mold as a body center plane according to a billet size parameter of the continuous casting machine; performing a billet thermomechanical coupling simulation on the grid-based billet structure model according to preset thermomechanical coupling parameters to obtain the simulation result of the continuous casting billet thermomechanical coupling model of the continuous casting machine.

3. The method of claim 2, wherein, The step of performing the billet thermomechanical coupling simulation on the grid-based billet structure model according to the preset thermomechanical coupling parameters to obtain the simulation result of the continuous casting billet thermomechanical coupling model of the continuous casting machine comprises: configuring a thermomechanical coupling state of a structure above the body center plane of the grid-based billet structure model as an initial state; configuring a superheat degree boundary condition, a superheat degree variation amplitude, an dummy bar pulling speed boundary condition and a dummy bar pulling speed variation amplitude of a structure below the body center plane of the grid-based billet structure model according to the thermomechanical coupling parameters; performing a simulation run on the semi-billet structure model with the thermomechanical coupling parameters configured to obtain the simulation result of the continuous casting billet thermomechanical coupling model.

4. The method of claim 2, wherein, The step of constructing the grid-based billet structure model with the meniscus position in the mold as the body center plane according to the billet size parameter of the continuous casting machine comprises: obtaining a structure symmetry direction of the continuous casting billet; constructing a semi-billet three-dimensional structure model with the meniscus position in the mold as the body center plane according to a size parameter in the structure symmetry direction; performing a non-uniform grid division processing on the semi-billet three-dimensional structure model to obtain the grid-based billet structure model.

5. The method according to any one of claims 1-4, characterized in that, Before the step of determining the cooling rate condition matched with the steel material to be cast by the continuous casting machine, the method further comprises: obtaining high-temperature confocal in-situ observation results collected in a hot ductility test process of samples of different cast steels; extracting a surface cooling rate of a (Cr, Fe) 7C 3 carbide with a size less than 10 μm from the high-temperature confocal in-situ observation results; configuring a cooling rate condition of the cast steel according to the surface cooling rate and constructing a mapping relationship between material parameters of the cast steel and the cooling rate condition.

6. An apparatus for determining continuous casting parameters of a ledeburite steel, characterized in that, The device is applied to the method for determining the continuous casting parameters of ledeburite steel according to any one of claims 1-5, and comprises: a determination module configured to determine a cooling rate condition matched with the steel material to be cast by the continuous casting machine, the cooling rate condition being determined based on a target carbide size of the steel material to be cast in a hot ductility test; An acquisition module is configured to acquire mold simulation data and secondary cooling zone simulation data satisfying the cooling rate condition from simulation results of a thermal-mechanical coupling model of a continuous casting billet of the continuous casting machine; A calculation module is configured to calculate mold control parameters according to the mold simulation data and calculate secondary cooling zone control parameters according to the secondary cooling zone simulation data; A sending module is configured to send the mold control parameters and the secondary cooling zone control parameters to a control end of the continuous casting machine, so that the continuous casting machine performs continuous casting production on the steel material to be cast according to the mold control parameters and the secondary cooling zone control parameters.

7. A storage medium, wherein at least one executable instruction is stored in the storage medium, and the executable instruction causes a processor to perform operations corresponding to the method for determining continuous casting parameters of ledeburite steel according to any one of claims 1-5.

8. A continuous casting machine, which is produced based on parameters determined by the method for determining continuous casting parameters of ledeburite steel according to any one of claims 1-5.

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