CN118122979A - Method, device, storage medium and continuous casting machine for determining continuous casting parameters of ledeburite steel - Google Patents

Abstract

The invention discloses a method and a device for determining continuous casting parameters of ledeburite steel, a storage medium and a continuous casting machine, relates to the technical field of casting, and mainly aims to solve the problem of high defective rate of ledeburite steel continuous casting production. The method mainly comprises the steps of determining a cooling rate condition matched with steel to be cast of a continuous casting machine, wherein the cooling rate condition is determined based on the (Cr, fe) 7C3 carbide size of the steel to be cast in a thermoplastic test; obtaining crystallizer simulation data of a crystallizer meeting the cooling rate condition and secondary cooling area simulation data of a secondary cooling area from simulation results of a continuous casting billet thermo-mechanical coupling model of a continuous casting machine; calculating according to the simulation data of the crystallizer to obtain a control parameter of the crystallizer, and calculating according to the simulation data of the secondary cooling zone to obtain a control parameter of the secondary cooling zone; and sending the crystallizer 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 steel to be cast according to the crystallizer control parameters and the secondary cooling zone control parameters. And determining the continuous casting parameters of the ledeburite steel of the main user.

Description

Method, device, storage medium and continuous casting machine for determining continuous casting parameters of ledeburite steel

Technical Field

The invention relates to the technical field of casting, and in particular to a method, a device, a storage medium and a continuous casting machine for determining continuous casting parameters of ledeburite steel.

Background technique

Continuous casting is continuous steel casting. Its specific process includes the molten steel continuously passing through the water-cooled crystallizer, being pulled out from the outlet below the crystallizer after solidifying into a hard shell, being cooled by water spray, and being cut into billets after being completely solidified. Compared with the traditional die casting process, the continuous casting process has better metal recovery rate and billet quality, and also has significant advantages in energy saving. As a high-carbon and high-chromium steel suitable for continuous casting process, ledeburite steel is widely used in cold working molds and is suitable for manufacturing various molds with complex shapes and heavy working conditions.

At present, the existing continuous casting parameter determination process of ledeburite steel mainly relies on the operator to configure the parameters of the continuous casting machine based on experience. However, due to the high carbon content of ledeburite steel, the liquidus temperature is more than 100°C lower than that of ordinary low-carbon steel, the protective slag is difficult to melt, and its thermal shrinkage coefficient is low and the shrinkage of the solidified billet shell is small. In the production process, it is easy for the protective slag to be difficult to flow into the channel between the billet and the crystallizer, the consumption of protective slag is reduced, the friction force is increased, and the surface of the continuous casting billet produced is prone to depression, which in turn induces quality problems such as longitudinal cracks and steel leakage.

Summary of the invention

In view of this, the present invention provides a method, device, storage medium and continuous casting machine for determining continuous casting parameters of ledeburite steel, the main purpose of which is to solve the problem of high defective rate in existing continuous casting production of ledeburite steel.

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

Determining a cooling rate condition that matches a steel material to be cast in a continuous casting machine, wherein the cooling rate condition is determined based on a target carbide size of the steel material to be cast in a hot plasticity test;

Acquire the simulation data of the crystallizer and the simulation data of the secondary cooling zone that meet the cooling rate condition from the simulation results of the thermo-mechanical coupling model of the continuous casting machine;

Calculating a crystallizer control parameter based on the crystallizer simulation data, and calculating a secondary cooling zone control parameter based on the secondary cooling zone simulation data;

The mold control parameters and the secondary cooling zone control parameters are sent to the control end of the continuous casting machine, so that the continuous casting machine performs continuous casting production on the steel to be cast according to the mold control parameters and the secondary cooling zone control parameters.

Furthermore, the crystallizer simulation data includes crystallizer superheat, dummy rod pulling speed and meniscus heat flux density, and the crystallizer control parameters calculated based on the crystallizer simulation data include:

Obtaining the cooling water temperature, ambient temperature and related dimensionless parameters of the continuous casting machine;

The water supply of the crystallizer is calculated based on the heat flux density of the meniscus, the cooling water temperature, the ambient temperature, the dimensionless parameter and the heat flux-water conversion relationship;

The crystallizer control parameters are generated according to the crystallizer water distribution, the crystallizer superheat and the dummy rod pulling speed.

Furthermore, the secondary cooling zone simulation data includes the heat flux density of the node surface of each cooling zone in the secondary cooling area, and the secondary cooling zone control parameters calculated based on the secondary cooling zone simulation data include:

For each cooling zone, the water flow density is calculated based on the node surface heat flux density, the cooling water temperature, and the associated dimensionless parameters;

The secondary cooling zone control parameters are generated according to the water flow density of each cooling zone.

Furthermore, before obtaining the crystallizer simulation data and the secondary cooling zone simulation data satisfying the cooling rate condition from the simulation results of the continuous casting billet thermo-mechanical coupling model of the continuous casting machine, the method further comprises:

According to the ingot size parameters of the continuous casting machine, a gridded ingot structure model is constructed with the meniscus position in the crystallizer as the body center plane;

The gridded billet structure model is subjected to a billet thermal-mechanical coupling simulation according to preset thermal-mechanical coupling parameters, and a simulation result of the continuous casting billet thermal-mechanical coupling model of the continuous casting machine is obtained.

Furthermore, the simulation result of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine by performing thermo-mechanical coupling simulation on the gridded casting billet structure model according to the preset thermo-mechanical coupling parameters includes:

The thermal-mechanical coupling state of the structure above the body center plane of the gridded ingot structure model is configured as an initial state;

According to the thermal-mechanical coupling parameters, 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 ingot structure model are configured;

The semi-cast billet structure model with completed thermal-mechanical coupling parameter configuration is simulated and run to obtain the simulation results of the continuous casting billet thermal-mechanical coupling model.

Furthermore, according to the ingot size parameters of the continuous casting machine, the meshed ingot structure model is constructed with the meniscus position in the crystallizer as the body center plane, including:

Obtaining the structural symmetry direction of the continuous casting machine billet;

According to the size parameters in the symmetric direction of the structure, a three-dimensional structural model of the semi-cast billet is constructed with the position of the meniscus in the crystallizer as the body center plane;

The three-dimensional structure model of the semi-cast billet is subjected to non-uniform grid division processing to obtain a gridded cast billet structure model.

Furthermore, before determining the cooling rate condition matching the steel to be cast of the continuous casting machine, the method further includes:

Obtain high-temperature confocal in-situ observation results of different cast steel samples during the hot plasticity test;

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

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.

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

A determination module, used to determine a cooling rate condition matching the steel to be cast of the continuous casting machine, wherein the cooling rate condition is determined based on a target carbide size of the steel to be cast in a thermoplastic test;

An acquisition module, used for acquiring the simulation data of the crystallizer and the simulation data of the secondary cooling zone that meet the cooling rate condition from the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine;

A calculation module, used for calculating the crystallizer control parameters according to the crystallizer simulation data, and calculating the secondary cooling zone control parameters according to the secondary cooling zone simulation data;

The sending module is used to send the crystallizer control parameters and the secondary cooling zone control parameters to the control end of the continuous casting machine, so that the continuous casting machine can continuously cast the steel to be cast according to the crystallizer control parameters and the secondary cooling zone control parameters.

Furthermore, the calculation module includes:

A first acquisition unit is used to acquire the cooling water temperature, the ambient temperature and related dimensionless parameters of the continuous casting machine;

A first calculation unit is used to calculate the water supply of the crystallizer according to the heat flux density of the meniscus, the cooling water temperature, the ambient temperature, the dimensionless parameter and the heat flux-water conversion relationship;

The first generating unit is used to generate a crystallizer control parameter according to the crystallizer water distribution, the crystallizer superheat and the dummy rod pulling speed.

Furthermore, the calculation module further includes:

A second calculation unit is used to calculate the water flow density for each cooling zone according to the node surface heat flux density, the cooling water temperature, and the associated dimensionless parameter;

The second generating unit is used to generate the second cooling zone control parameter according to the water flow density of each cooling zone.

Furthermore, the device also includes:

A construction module is used to construct a gridded billet structure model according to billet size parameters of the continuous casting machine and with the meniscus position in the crystallizer as the body center plane;

The simulation module is used to perform a thermo-mechanical coupling simulation of the gridded ingot structure model according to preset thermo-mechanical coupling parameters, and obtain the simulation results of the thermo-mechanical coupling model of the continuous casting machine.

Furthermore, the simulation module includes:

A first configuration unit is used to configure the thermal-mechanical coupling state of the structure above the body center plane of the gridded ingot structure model as an initial state;

A 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 ingot structure model according to the thermal-mechanical coupling parameters;

The simulation unit is used to simulate the semi-cast billet structure model with completed thermal-mechanical coupling parameter configuration to obtain the simulation result of the continuous casting billet thermal-mechanical coupling model.

Furthermore, the building block includes:

A second acquisition unit is used to acquire the structural symmetry direction of the continuous casting machine billet;

A frame unit, used to construct a three-dimensional structure model of the semi-cast billet according to the size parameters in the symmetric direction of the structure and taking the meniscus position in the crystallizer as the body center plane;

The mesh division unit is used to perform non-uniform mesh division processing on the three-dimensional structure model of the semi-cast billet to obtain a meshed cast billet structure model.

Furthermore, the device also includes:

The acquisition module is also used to obtain high-temperature confocal in-situ observation results collected during the thermoplasticity test of samples of different cast steels;

An extraction module, used to extract the surface cooling rate of (Cr,Fe)7C3 carbides with a size less than 10 μm in the high-temperature confocal in-situ observation result;

A 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.

According to another aspect of the present invention, a storage medium is provided, wherein at least one executable instruction is stored in the storage medium, and the executable instruction enables a processor to execute operations corresponding to the above-mentioned method for determining continuous casting parameters of ledeburite steel.

According to yet another aspect of the present invention, there is provided a continuous casting machine, wherein the continuous casting machine is produced based on the parameters determined by the method for determining continuous casting parameters of ledeburite steel according to any one of claims 1 to 7.

By means of the above technical solution, the technical solution provided by the embodiment of the present invention has at least the following advantages:

The present invention provides a method, device, storage medium and continuous casting machine for determining continuous casting parameters of ledeburite steel. The embodiment of the present invention determines a cooling rate condition that matches a steel to be cast of the continuous casting machine, wherein the cooling rate condition is determined based on a target carbide size of the steel to be cast in a thermoplastic test; obtains crystallizer simulation data and secondary cooling zone simulation data that meet the cooling rate condition from simulation results of a continuous casting billet thermo-mechanical coupling model of the continuous casting machine; calculates a crystallizer control parameter based on the crystallizer simulation data, and calculates a secondary cooling zone control parameter based on the secondary cooling zone simulation data; sends the crystallizer control parameter and the secondary cooling zone control parameter to a control end of the continuous casting machine, so that the continuous casting machine performs continuous casting production on the steel to be cast according to the crystallizer control parameter and the secondary cooling zone control parameter, thereby greatly improving the accuracy of water volume control in the cooling zone, avoiding uncertainty in equipment regulation based on manual experience, and at the same time ensuring the accuracy of water volume control of the continuous casting machine, reducing the possibility of cooling mass temperature, thereby effectively reducing the defective rate of continuous casting output.

The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

FIG1 shows a flow chart of a method for determining continuous casting parameters of ledeburite steel provided in an embodiment of the present invention;

FIG2 shows a schematic diagram of a continuous casting process of a continuous casting machine provided by an embodiment of the present invention;

FIG3 shows a flow chart of another method for determining continuous casting parameters of ledeburite steel provided in an embodiment of the present invention;

FIG4 is a schematic diagram showing a solidification process of a continuous casting billet provided by an embodiment of the present invention;

FIG5 shows a schematic diagram of a continuous casting billet model provided by an embodiment of the present invention;

FIG6 shows a block diagram of a device for determining continuous casting parameters of ledeburite steel provided in an embodiment of the present invention.

Detailed ways

The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

Aiming at the problem of high defective rate in existing continuous casting production of ledeburite steel, an embodiment of the present invention provides a method for determining continuous casting parameters of ledeburite steel, as shown in FIG1 , the method comprising:

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

In an embodiment of the present invention, a continuous casting machine is a continuous casting execution device that needs to determine the parameters of the continuous casting of ledeburite steel. For example, a continuous casting machine as shown in FIG2 mainly includes a continuous casting machine mainly composed of an intermediate tank, a crystallizer, a secondary cooling channel, a dummy rod, a straightening machine and other structures. In the continuous casting production process, during the continuous casting production process, the molten steel of the steel to be cast in the tundish enters the crystallizer through the water inlet, and the molten steel is rapidly solidified by the strong cooling effect in the crystallizer to form a billet shell, and then it is pulled out at a certain speed by the dummy rod, and continues to cool in the subsequent secondary cooling zone and air cooling zone. The molten steel is completely solidified at the solidification end position, and the conversion of the molten steel to the billet is completed at the end of the casting machine. In the continuous casting process, the cooling process of the continuous casting billet is a process in which carbides precipitate at the austenite grain boundary and coarsen as the continuous casting billet cools. It is also a process in which high-hardness compounds that cause cracks in the billet are precipitated. Therefore, the cooling rate is a key factor affecting the output quality. The steel to be cast is any existing ledeburite steel, such as molten steel of Cr12 die steel, Cr12MoV alloy tool steel, Cr12W wear-resistant cold working die steel, etc. The cooling rate (cooling rate) conditions corresponding to ledeburite steels with different material parameters are different, so it is necessary to determine the cooling rate conditions that match the current steel to be cast.

It should be noted that the cooling rate condition is determined based on the (Cr,Fe)7C3 carbide size of the steel to be cast in the thermoplastic test. Since the size and distribution of (Cr,Fe)7C3 carbides are the key to improving the quality of the ingot during the continuous casting process, thermoplastic experiments are conducted on the cast steel in advance to determine the optimal surface cooling rate conditions for different cast steels through this experiment, and then the cooling rate condition is used as the cooling control target for the continuous casting machine crystallizer and secondary cooling area, and the continuous casting production parameters are reversed.

102. Acquire crystallizer simulation data and secondary cooling zone simulation data that meet the cooling rate condition from the simulation results of the continuous casting billet thermo-mechanical coupling model of the continuous casting machine.

In an embodiment of the present invention, after determining the cooling rate conditions, in order to determine the accurate continuous casting parameters, a three-dimensional model is constructed in advance according to the equipment parameters of the current continuous casting machine, and a thermomechanical coupling simulation of the continuous casting process is performed for the steel to be cast, and simulation data under different cooling rates are obtained, and then the crystallizer simulation data and the secondary cooling zone simulation data that meet the cooling rate conditions are screened out from the simulation results. Among them, the model construction can be based on the finite element software MSC.MARC as a simulation platform for three-dimensional modeling, and can also be based on other finite element software, which is not specifically limited in the embodiment of the present invention. By constructing a three-dimensional model of the continuous casting machine and simulating the continuous casting process, it is possible to avoid on-site debugging of the continuous casting machine, while ensuring the correctness of the continuous casting process data, greatly improving the efficiency of data determination and reducing the equipment debugging cost.

103. Calculate a crystallizer control parameter based on the crystallizer simulation data, and calculate a secondary cooling zone control parameter based on the secondary cooling zone simulation data.

In an embodiment of the present invention, the simulation data includes equipment operation data and steel performance data of the continuous casting process, for example, crystallizer superheat, ingot rod pulling speed, steel heat flux density, etc. Since some of these data are equipment operation control parameters, such as ingot rod pulling speed, and some are result data, such as steel heat flux density, for result data, it is necessary to infer the control parameters of the equipment based on the results. For example, the water distribution of the cooling water of the crystallizer is the main factor affecting the heat flux density of the meniscus of the crystallizer. The relationship formula between the water distribution and the heat flux density of the meniscus can be derived based on historical production data, and the water distribution can be calculated based on this relationship formula and the heat flux density of the meniscus in the simulation data. For another example, the water flow density of each cooling section can be calculated based on the heat flux density of each cooling section in the secondary cooling zone and the relationship formula between the heat flux density and the water flow density.

104. Send the crystallizer control parameters and the secondary cooling zone control parameters to the control end of the continuous casting machine, so that the continuous casting machine performs continuous casting production on the steel to be cast according to the crystallizer control parameters and the secondary cooling zone control parameters.

In the embodiment of the present invention, after the crystallizer control parameters and the secondary cooling zone control parameters are determined, these parameters are sent to the control end of the continuous casting machine, so that the control end of the continuous casting machine configures the corresponding parameters to the corresponding cooling execution end, and performs continuous casting production according to the crystallizer control parameters and the secondary cooling zone control parameters during the continuous casting production of the steel to be cast. The control end may be an industrial computer or a control device corresponding to different execution ends, such as a programmable controller, which is not specifically limited in the embodiment of the present invention.

It should be noted that by conducting thermoplastic tests on the steel to be cast, the optimal cooling rate conditions are determined based on the key factors affecting the quality of the continuous casting billet ((Cr,Fe)7C3 carbide size), and the production data under the cooling rate conditions are simulated based on the three-dimensional model of the continuous casting machine. Then, the control parameters of the continuous casting machine are deduced based on the production data, which improves the reliability of the control parameter configuration basis and greatly increases the accuracy of the control parameters. At the same time, the debugging time of the continuous casting machine is greatly reduced, thereby ensuring the production quality of ledeburite steel continuous casting and reducing the defective rate.

In another embodiment of the present invention, for further explanation and limitation, as shown in FIG3 , the step 103 of calculating the crystallizer control parameters according to the crystallizer simulation data includes:

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

202. The water supply of the crystallizer is calculated based on the heat flux density of the meniscus, the cooling water temperature, the ambient temperature, the dimensionless parameters and the heat flux density-water volume conversion relationship.

203. Generate a crystallizer control parameter according to the crystallizer water distribution, the crystallizer superheat and the dummy rod pulling speed.

In the embodiment of the present invention, the crystallizer simulation data includes the crystallizer superheat, the dummy rod pulling speed and the meniscus heat flux. The above simulation parameters can be extracted from the simulation results of the continuous casting billet thermal-mechanical coupling model. The dummy rod pulling speed and the meniscus heat flux are set to W, the ambient temperature is T ₀ , the cooling water temperature is T _w , and the crystallizer water distribution is L. The conversion relationship between the crystallizer water distribution and the meniscus heat flux is:

Among them, _Cm is a dimensionless constant related to the equipment parameters of the continuous casting machine, and its value is generally [4,5], such as 4.183; the temperature difference value of _Tw - _T0 can be calculated based on the ambient temperature and cooling water temperature collected by the on-site temperature sensor, or it can be taken based on experience that the ambient temperature is ℃ and the temperature difference is in the range of 5.5℃-8℃, such as 6℃; S is the contact surface area between the crystallizer and the water distribution, which can be calculated based on the equipment parameters of the continuous casting machine. The water distribution amount of the crystallizer can be calculated according to formula (1). By using the conversion relationship between the water distribution amount of the crystallizer and the heat flux density of the meniscus, the water distribution amount of the crystallizer can be inferred according to the heat flux density of the meniscus obtained by simulation, and the cooling water distribution amount of the crystallizer can be accurately calculated, thereby realizing the precise control of the cooling temperature and cooling rate of the crystallizer section, thereby greatly reducing the possibility of quality problems in the continuous casting billet during the cooling stage of the crystallizer, and greatly reducing the defective rate of the continuous casting billet.

In another embodiment of the present invention, for further explanation and limitation, the step of calculating the control parameters of the second cooling zone according to the simulation data of the second cooling zone includes:

For each cooling zone, the water flow density is calculated based on the node surface heat flux density, the cooling water temperature, and the associated dimensionless parameters;

The secondary cooling zone control parameters are generated according to the water flow density of each cooling zone.

In the embodiment of the present invention, the simulation data of the secondary cooling zone includes the heat flux density of the node surface of each cooling zone in the secondary cooling zone, that is, the secondary cooling zone generally includes 8 to 10 cooling zones, and the heat flux density of the node surface of any cooling zone can be extracted from the simulation results. Assuming the heat flux density of the node surface of any cooling zone in the secondary cooling zone is _Wi , the calculation formula of the water flow density ρ of this cooling zone is:

Through the above formula, the water flow density of any cooling zone in the secondary cooling area can be calculated, and then the cooling rate of the secondary cooling area can be accurately controlled, thereby greatly reducing the possibility of quality problems in the continuous casting billet during the secondary cooling stage and greatly reducing the defective rate of the continuous casting billet.

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

According to the ingot size parameters of the continuous casting machine, a gridded ingot structure model is constructed with the meniscus position in the crystallizer as the body center plane;

The gridded billet structure model is subjected to a billet thermal-mechanical coupling simulation according to preset thermal-mechanical coupling parameters, and a simulation result of the continuous casting billet thermal-mechanical coupling model of the continuous casting machine is obtained.

In the embodiment of the present invention, the finite element software MSC.Marc is used to establish a thermal/mechanical coupling model of the entire continuous casting process. This model is constructed under the conditions of temperature load and molten steel static pressure during continuous casting. As shown in Figure 4, it is a schematic diagram of the solidification of the continuous casting billet. The X-axis direction is the thickness direction of the billet, the Z-axis direction is the width direction of the billet, the negative direction of the Y-axis is the direction of the billet drawing, the unit layer located in the XOZ plane is the meniscus position in the crystallizer, and the YOZ plane represents the symmetry plane in the width direction. In order to improve the simulation accuracy, the continuous casting billet is tetrahedral meshed using non-uniform meshing technology. The unit side length can be 15mm, and it can also be customized according to actual application requirements. The embodiment of the present invention does not make specific restrictions. Since the calculation error will increase when the middle is dense and the two sides are sparse, therefore, when meshing, the grid configuration close to the edge is finer, and the grid configuration in the middle is relatively sparse, so as to use a denser grid to more accurately describe the changes in its variables, thereby effectively improving the calculation accuracy.

In another embodiment of the present invention, for further explanation and limitation, the step of performing a thermo-mechanical coupling simulation of the gridded slab structure model according to preset thermo-mechanical coupling parameters to obtain a simulation result of the thermo-mechanical coupling model of the continuous casting machine includes:

The thermal-mechanical coupling state of the structure above the body center plane of the gridded ingot structure model is configured as an initial state;

According to the thermal-mechanical coupling parameters, 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 ingot structure model are configured;

The semi-cast billet structure model with completed thermal-mechanical coupling parameter configuration is simulated and run to obtain the simulation results of the continuous casting billet thermal-mechanical coupling model.

In the embodiment of the present invention, in order to prevent the continuous casting unit that has entered the crystallizer from affecting the temperature and structural deformation of the continuous casting unit that has not entered the crystallizer during the cooling deformation process, the continuous casting unit in the continuous casting above the meniscus is kept in the initial state through the MARC secondary development technology, and the thermal-mechanical coupling process will only occur when the unit is below the meniscus. That is, only the continuous casting structure below the meniscus is configured with superheat boundary conditions, superheat variation range, dummy bar pulling speed boundary conditions and dummy bar pulling speed variation range. Among them, the superheat boundary conditions can be 20°C at the lower boundary and 30°C at the upper boundary, and the superheat variation range is 2°C apart from the temperature difference. The pulling speed boundary conditions can be 1.1m/min at the upper boundary, 0.6m/min at the lower boundary, and the pulling speed variation range is 0.1m/min. Of course, the superheat boundary conditions, superheat variation range, dummy bar pulling speed boundary conditions and dummy bar pulling speed variation range can also be customized according to actual application requirements, and the embodiment of the present invention does not make specific restrictions. In the simulation process, the casting speed and superheat are combined and adjusted to obtain multiple groups of continuous casting billet surface temperature, average cooling rate, and heat flux density. In this process, the influence of mold vibration on heat transfer is ignored; the influence of molten steel flow in the crystallizer on the coupling process is not considered.

In another embodiment of the present invention, for further explanation and limitation, the steps are based on the billet size parameters of the continuous casting machine, taking the meniscus position in the crystallizer as the body center plane, and constructing a gridded billet structure model, including:

Obtaining the structural symmetry direction of the continuous casting machine billet;

According to the size parameters in the symmetric direction of the structure, a three-dimensional structural model of the semi-cast billet is constructed with the position of the meniscus in the crystallizer as the body center plane;

The three-dimensional structure model of the semi-cast billet is subjected to non-uniform grid division processing to obtain a gridded cast billet structure model.

In the embodiment of the present invention, generally, the structural symmetry direction of the continuous casting machine billet is the width direction, that is, the billet has symmetry along the width direction. If the complete continuous casting billet is modeled, the calculation cost is high. Due to the existence of symmetry, half of the billet width direction is selected for modeling, thereby saving the calculation cost. Due to the limited length of the billet model and the bite effect at the billet head, the head and tail positions of the billet cannot reflect the actual deformation of the billet when in contact with the casting roller. Therefore, an intermediate surface is set in the middle position of the billet in the direction of billet drawing in the model. As shown in Figure 5, a continuous casting billet model has a size of 200mm×100mm×3000mm (width direction×thickness direction×bill drawing direction), and the billet length in the model is 3000mm. The intermediate surface is far enough from the head and tail positions of the billet, and the bite effect has little effect on this position. The position of the intermediate surface can better reflect the actual deformation of the billet.

In another embodiment of the present invention, for further explanation and limitation, before the step of determining the cooling rate condition matching the steel to be cast of the continuous casting machine, the method further includes:

Obtain high-temperature confocal in-situ observation results of different cast steel samples during the hot plasticity test;

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

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.

In the embodiment of the present invention, in order to determine the accurate cooling rate conditions, different cast steels that are expected to be continuously cast are taken and made into thermoplastic test samples. The specific process of thermoplastic testing of any continuous casting steel includes: sampling at 1/4 of the bottom surface of the ingot, avoiding the central area where central segregation, shrinkage and shrinkage are more serious. The sample is wire cut into small cylinders (such as 4mm in diameter and 1.5mm in height). The surface of the small cylinder is conventionally ground and polished to keep the measured surface smooth. The polished sample is placed in an alumina crucible and placed in a pt sample holder with an R-type thermocouple. After the gas in the furnace chamber is evacuated with a vacuum pump, argon gas is continuously blown into the furnace chamber to avoid oxidation of the sample surface. The laser beam is heated on the upper surface of the sample at a rate of 15khz. All samples are heated to 200℃ at a rate of 0.8℃/s, and then heated to 1450℃ at a rate of 5℃/s, and kept warm for 5min to fully melt. The samples were then cooled to 700°C at cooling rates of 0.2°C/s, 3°C/s, 5°C/s, and 7°C/s, respectively, and then quenched. During this process, the high-temperature confocal equipment conducted in-situ observations and metallographic structure observations on the solidification of ledeburite steel, determined the cooling rate when the size of (Cr,Fe)7C3 was less than 10μm, and based on this cooling rate, the cooling rate conditions were determined. For example, the range of the secondary cooling rate ±0.1°C was determined as the cooling rate condition. In order for different cast steels to be quickly matched to the corresponding cooling rate conditions in the future, a mapping relationship between different cast steels and the cooling rate conditions obtained from the test is constructed, so that the corresponding cooling rate conditions can be determined according to the current steel to be cast before the actual production of the continuous casting machine.

The present invention provides a method for determining continuous casting parameters of ledeburite steel. The embodiment of the present invention determines a cooling rate condition that matches a steel to be cast of a continuous casting machine, wherein the cooling rate condition is determined based on a target carbide size of the steel to be cast in a thermoplastic test; obtains crystallizer simulation data and secondary cooling zone simulation data that meet the cooling rate condition from a simulation result of a continuous casting billet thermo-mechanical coupling model of the continuous casting machine; calculates a crystallizer control parameter based on the crystallizer simulation data, and calculates a secondary cooling zone control parameter based on the secondary cooling zone simulation data; sends the crystallizer control parameter and the secondary cooling zone control parameter to a control end of the continuous casting machine, so that the continuous casting machine performs continuous casting production on the steel to be cast according to the crystallizer control parameter and the secondary cooling zone control parameter, thereby greatly improving the accuracy of water volume control in the cooling zone, avoiding uncertainty in equipment regulation based on manual experience, and at the same time ensuring the accuracy of water volume control of the continuous casting machine, reducing the possibility of cooling mass temperature, thereby effectively reducing the defective rate of continuous casting output.

Further, as an implementation of the method shown in FIG. 1 , an embodiment of the present invention provides a device for determining continuous casting parameters of ledeburite steel, as shown in FIG. 6 , the device includes:

A determination module 31 is used to determine a cooling rate condition that matches the steel to be cast of the continuous casting machine, wherein the cooling rate condition is determined based on a target carbide size of the steel to be cast in a thermoplastic test;

An acquisition module 32, configured to acquire, from the simulation results of the thermo-mechanical coupling model of the continuous casting slab 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 condition;

A calculation module 33, used for calculating the crystallizer control parameters according to the crystallizer simulation data, and calculating the secondary cooling zone control parameters according to the secondary cooling zone simulation data;

The sending module 34 is used to send the crystallizer control parameters and the secondary cooling zone control parameters to the control end of the continuous casting machine, so that the continuous casting machine performs continuous casting production on the steel to be cast according to the crystallizer control parameters and the secondary cooling zone control parameters.

Furthermore, the calculation module includes:

A first acquisition unit is used to acquire the cooling water temperature, the ambient temperature and related dimensionless parameters of the continuous casting machine;

A first calculation unit is used to calculate the water supply of the crystallizer according to the heat flux density of the meniscus, the cooling water temperature, the ambient temperature, the dimensionless parameter and the heat flux-water conversion relationship;

The first generating unit is used to generate a crystallizer control parameter according to the crystallizer water distribution, the crystallizer superheat and the dummy rod pulling speed.

Furthermore, the calculation module further includes:

A second calculation unit is used to calculate the water flow density for each cooling zone according to the node surface heat flux density, the cooling water temperature, and the associated dimensionless parameter;

The second generating unit is used to generate the second cooling zone control parameter according to the water flow density of each cooling zone.

Furthermore, the device also includes:

A construction module is used to construct a gridded billet structure model according to billet size parameters of the continuous casting machine and with the meniscus position in the crystallizer as the body center plane;

The simulation module is used to perform a thermo-mechanical coupling simulation of the gridded ingot structure model according to preset thermo-mechanical coupling parameters, and obtain the simulation results of the thermo-mechanical coupling model of the continuous casting machine.

Furthermore, the simulation module includes:

A first configuration unit is used to configure the thermal-mechanical coupling state of the structure above the body center plane of the gridded ingot structure model as an initial state;

A 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 ingot structure model according to the thermal-mechanical coupling parameters;

The simulation unit is used to simulate the semi-cast billet structure model with completed thermal-mechanical coupling parameter configuration to obtain the simulation result of the continuous casting billet thermal-mechanical coupling model.

Furthermore, the building block includes:

A second acquisition unit is used to acquire the structural symmetry direction of the continuous casting machine billet;

A frame unit, used to construct a three-dimensional structure model of the semi-cast billet according to the size parameters in the symmetric direction of the structure and taking the meniscus position in the crystallizer as the body center plane;

The mesh division unit is used to perform non-uniform mesh division processing on the three-dimensional structure model of the semi-cast billet to obtain a meshed cast billet structure model.

Furthermore, the device also includes:

The acquisition module is also used to obtain high-temperature confocal in-situ observation results collected during the thermoplasticity test of samples of different cast steels;

An extraction module, used for extracting the surface cooling rate of the (Cr,Fe)7C3 carbide with a size less than 10 μm in the high-temperature confocal in-situ observation result;

A 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.

The present invention provides a device for determining continuous casting parameters of ledeburite steel. The embodiment of the present invention determines a cooling rate condition that matches a steel to be cast of a continuous casting machine, wherein the cooling rate condition is determined based on a target carbide size of the steel to be cast in a thermoplastic test; obtains crystallizer simulation data and secondary cooling zone simulation data that meet the cooling rate condition from simulation results of a continuous casting billet thermo-mechanical coupling model of the continuous casting machine; calculates a crystallizer control parameter based on the crystallizer simulation data, and calculates a secondary cooling zone control parameter based on the secondary cooling zone simulation data; sends the crystallizer control parameter and the secondary cooling zone control parameter to a control end of the continuous casting machine, so that the continuous casting machine performs continuous casting production on the steel to be cast according to the crystallizer control parameter and the secondary cooling zone control parameter, thereby greatly improving the accuracy of water volume control in the cooling zone, avoiding uncertainty in equipment regulation based on manual experience, and at the same time ensuring the accuracy of water volume control of the continuous casting machine, reducing the possibility of cooling mass temperature, thereby effectively reducing the defective rate of continuous casting output.

According to one embodiment of the present invention, a storage medium is provided, wherein the storage medium stores at least one executable instruction, and the computer executable instruction can execute the method for determining continuous casting parameters of ledeburite steel in any of the above method embodiments.

According to one embodiment of the present invention, a continuous casting machine is provided, wherein the continuous casting machine is produced based on parameters determined by the method for determining continuous casting parameters of ledeburite steel according to any one of claims 1 to 7.

Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, and optionally, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. A method for determining continuous casting parameters of ledeburite steel, characterized in that it comprises: Determining a cooling rate condition that matches a steel material to be cast in a continuous casting machine, wherein the cooling rate condition is determined based on a target carbide size of the steel material to be cast in a hot plasticity test; Acquire the simulation data of the crystallizer and the simulation data of the secondary cooling zone that meet the cooling rate condition from the simulation results of the thermo-mechanical coupling model of the continuous casting slab of the continuous casting machine; Calculating a crystallizer control parameter based on the crystallizer simulation data, and calculating a secondary cooling zone control parameter based on the secondary cooling zone simulation data; The mold control parameters and the secondary cooling zone control parameters are sent to the control end of the continuous casting machine, so that the continuous casting machine performs continuous casting production on the steel to be cast according to the mold control parameters and the secondary cooling zone control parameters. 2. The method according to claim 1, characterized in that the mold simulation data includes mold superheat, dummy rod pulling speed and meniscus heat flux density, and the mold control parameters are calculated based on the mold simulation data, comprising: Obtaining cooling water temperature, ambient temperature and related dimensionless parameters of the continuous casting machine; The water supply of the crystallizer is calculated based on the heat flux density of the meniscus, the cooling water temperature, the ambient temperature, the dimensionless parameter and the heat flux-water conversion relationship; The crystallizer control parameters are generated according to the crystallizer water distribution, the crystallizer superheat and the dummy rod pulling speed. 3. The method according to claim 2, characterized in that the secondary cooling zone simulation data includes the node surface heat flux density of each cooling zone in the secondary cooling area, and the secondary cooling zone control parameters are calculated based on the secondary cooling zone simulation data, including: For each cooling zone, the water flow density is calculated based on the node surface heat flux density, the cooling water temperature, and the associated dimensionless parameters; The secondary cooling zone control parameters are generated according to the water flow density of each cooling zone. 4. The method according to claim 1, characterized in that before obtaining the crystallizer simulation data and the secondary cooling zone simulation data satisfying the cooling rate condition from the simulation results of the continuous casting billet thermo-mechanical coupling model of the continuous casting machine, the method further comprises: According to the ingot size parameters of the continuous casting machine, a gridded ingot structure model is constructed with the meniscus position in the crystallizer as the body center plane; The gridded billet structure model is subjected to a billet thermal-mechanical coupling simulation according to preset thermal-mechanical coupling parameters, and a simulation result of the continuous casting billet thermal-mechanical coupling model of the continuous casting machine is obtained. 5. The method according to claim 4, characterized in that the simulation result of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine by performing thermo-mechanical coupling simulation on the gridded billet structure model according to preset thermo-mechanical coupling parameters comprises: The thermal-mechanical coupling state of the structure above the body center plane of the gridded ingot structure model is configured as an initial state; According to the thermal-mechanical coupling parameters, 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 ingot structure model are configured; The semi-cast billet structure model with completed thermal-mechanical coupling parameter configuration is simulated and run to obtain the simulation results of the continuous casting billet thermal-mechanical coupling model. 6. The method according to claim 4, characterized in that the gridded ingot structure model is constructed based on the ingot size parameters of the continuous casting machine and with the meniscus position in the crystallizer as the body center plane, comprising: Obtaining the structural symmetry direction of the continuous casting machine billet; According to the size parameters in the symmetric direction of the structure, a three-dimensional structural model of the semi-cast billet is constructed with the position of the meniscus in the crystallizer as the body center plane; The three-dimensional structure model of the semi-cast billet is subjected to non-uniform grid division processing to obtain a gridded cast billet structure model. 7. The method according to any one of claims 1 to 6, characterized in that before determining the cooling rate condition matching the steel to be cast of the continuous casting machine, the method further comprises: Obtain high-temperature confocal in-situ observation results of different cast steel samples during the hot plasticity test; Extracting the surface cooling rate of (Cr,Fe)7C3 carbides with a size less than 10 μm in the high temperature confocal in-situ observation results; 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. 8. A device for determining continuous casting parameters of ledeburite steel, characterized in that it comprises: A determination module, used to determine a cooling rate condition matching the steel to be cast of the continuous casting machine, wherein the cooling rate condition is determined based on a target carbide size of the steel to be cast in a thermoplastic test; An acquisition module, used for acquiring the simulation data of the crystallizer and the simulation data of the secondary cooling zone that meet the cooling rate condition from the simulation results of the thermo-mechanical coupling model of the continuous casting billet of the continuous casting machine; A calculation module, used for calculating the crystallizer control parameters according to the crystallizer simulation data, and calculating the secondary cooling zone control parameters according to the secondary cooling zone simulation data; The sending module is used to send the crystallizer control parameters and the secondary cooling zone control parameters to the control end of the continuous casting machine, so that the continuous casting machine can continuously cast the steel to be cast according to the crystallizer control parameters and the secondary cooling zone control parameters. 9. A storage medium, wherein at least one executable instruction is stored in the storage medium, wherein the executable instruction enables a processor to execute operations corresponding to the method for determining continuous casting parameters of ledeburite steel according to any one of claims 1 to 7. 10. A continuous casting machine, the continuous casting machine being produced based on the parameters determined by the method for determining continuous casting parameters of ledeburite steel according to any one of claims 1 to 7.