CN115383071A - Quenching process design method - Google Patents
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- 230000000171 quenching effect Effects 0.000 title claims abstract description 340
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- 238000009749 continuous casting Methods 0.000 claims abstract description 119
- 238000005266 casting Methods 0.000 claims abstract description 36
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- 239000007790 solid phase Substances 0.000 claims description 3
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- 238000001816 cooling Methods 0.000 description 11
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- 238000011160 research Methods 0.000 description 3
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- 229910000831 Steel Inorganic materials 0.000 description 2
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
- C21D11/005—Process control or regulation for heat treatments for cooling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
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Abstract
The invention provides a quenching process design method, which comprises the following steps: calculating the quenching medium temperature at the end of quenching according to the casting blank temperature field in the quenching process, the given initial quenching medium temperature, the given initial quenching medium capacity and the given quenching time; establishing a corresponding relation among the initial quenching medium temperature, the quenching medium temperature at the end of quenching and the quenching medium capacity; and according to the corresponding relation, designing the capacity of the quenching medium in the quenching process of the continuous casting billet according to the preset initial quenching medium temperature, the preset quenching medium temperature at the end of quenching and the preset quenching temperature rise threshold. The invention can solve the problem that a reasonable design method of a groove type quenching process capable of accurately simulating the quenching process is lacked at present.
Description
Technical Field
The invention relates to the technical field of continuous casting processing, in particular to a quenching process design method.
Background
The surface quenching technology in the continuous casting process is an effective technology for solving the problem of high-temperature hot delivery surface heat cracks or wide and thick plate corner cracks of a variety steel continuous casting billet, can obviously improve the production efficiency and reduce the production cost. The surface quenching process simulation model plays an important role in quantitative research of surface quenching process parameters, equipment model selection design and the like, and can remarkably improve the effectiveness and quality of design, so that the final use effect of the surface quenching technology is ensured.
In the surface quenching simulation process, the temperature of the quenching medium has obvious influence on the heat exchange coefficient, so calculation results, process research and the like are influenced, particularly for water-cooling trough type quenching, the temperature of the quenching medium in a quenching device is a changing process in the quenching process of a continuous casting blank, the temperature of the quenching medium is continuously increased on the basis of the initial temperature due to the release of the heat of the casting blank, and if the temperature changing process is calculated according to the constant temperature of the quenching medium, the result is greatly deviated from the actual condition, so the distortion of the process research is caused, and therefore, the processing of a simulation method is necessary.
On the basis that the quantity of the quenching medium in the quenching device is selected to be small, the temperature rise of the quenching medium in the quenching process is too large, the quenching effect is influenced, the surface quenching target cannot be achieved, and even casting blank defects are caused; if the quantity of the quenching medium is selected to be larger, the consumption of the quenching medium of the quenching system is increased, and the system load is increased.
Because a searching method capable of accurately simulating the quenching process is lacked at present, a reasonable design method of a cooling tank type quenching process is provided urgently.
Disclosure of Invention
In view of the above problems, the present invention aims to provide a method for designing a quenching process, so as to solve the problem that a reasonable design method for a trough type quenching process capable of accurately simulating a quenching process is absent at present.
The invention provides a quenching process design method, which comprises the following steps:
s1, calculating the temperature of a quenching medium at the end of quenching according to a casting blank temperature field in the quenching process, the given initial quenching medium temperature, the given initial quenching medium capacity and the given quenching time;
s2, establishing a corresponding relation among the initial quenching medium temperature, the quenching medium temperature at the end of quenching and the quenching medium capacity;
s3, designing the capacity of the quenching medium in the quenching process of the continuous casting billet according to the corresponding relation and the preset initial quenching medium temperature, the preset quenching medium temperature at the end of quenching and the preset quenching temperature rise threshold;
the preset quenching temperature rise threshold value is a process reasonable value of the temperature difference between the quenching medium temperature and the preset initial quenching medium temperature at the preset quenching end.
In addition, it is preferable that the calculating of the quenching medium temperature at the end of quenching, based on the casting blank temperature field of the quenching process, the given initial quenching medium temperature, the given initial quenching medium capacity, and the given quenching time, includes:
a1, performing real-time tracking calculation on a temperature field of a continuous casting blank quenching process through a temperature field calculation model to obtain a continuously-changed casting blank temperature field;
a2, calculating the heat quantity led out from the continuous casting billet within a preset time step according to the temperature field of the casting billet, the temperature of the initial quenching medium and the heat exchange coefficient of the surface of the casting billet;
a3, calculating the heat absorbed by the quenching medium in the preset time step according to the heat derived from the continuous casting billet in the preset time step and a preset effective coefficient;
a4, calculating the temperature of the quenching medium after the preset time step is finished according to the heat absorbed by the quenching medium in the preset time step and the corresponding temperature of the quenching medium after the previous preset time step is finished;
and A5, repeating the steps A2-A4 until the quenching is finished, and obtaining the temperature of the quenching medium at the end of the quenching.
In addition, the preferable scheme is that the temperature field calculation model calculates the temperature field of the continuous casting billet by adopting a conversion temperature and conversion enthalpy method, and the calculation formula comprises the following calculation formula:
differential simplified equation for heat transfer:
wherein rho is the density of the continuous casting billet, t is the heat transfer time, and lambda 0 Is the reference temperature T 0 The heat conductivity coefficient phi is the conversion temperature, and H is the enthalpy;
the calculation formula of enthalpy is:
wherein, T 0 Is an optional reference temperature, H 0 Is the corresponding reference enthalpy, L is the latent heat of solidification, c p (τ) is the specific heat at temperature τ, f s The solid phase ratio;
the conversion temperature and temperature corresponding relation formula is as follows:
wherein λ is 0 Is the reference temperature T 0 Thermal conductivity of (1); λ (t) is the thermal conductivity at temperature t.
In addition, it is preferable that the calculating the heat derived from the continuous casting slab within the preset time step according to the casting slab temperature field, the initial quenching medium temperature, and the heat transfer coefficient of the casting slab surface includes:
calculating the heat flow of the continuous casting billet according to the temperature field of the continuous casting billet and the heat exchange coefficient of the surface of the casting billet within a preset time step; wherein the heat transfer coefficient of the surface of the casting blank and the temperature of the quenching medium are related functions, and h = f (Tw); wherein h is the heat exchange coefficient of the surface of the casting blank, and Tw is the temperature of the quenching medium;
and calculating the heat quantity led out from the continuous casting billet within a preset time step according to the heat flow of the continuous casting billet and the temperature of the initial quenching medium.
In addition, a preferable scheme is that the boundary heat exchange in the quenching process of the continuous casting billet adopts a third boundary condition, and the third boundary condition is as follows:
q＝h*(Tsurface-Twater)；
and when the heat flow of the continuous casting billet in the first preset time step is calculated, the temperature of the last preset time step of the quenching medium is the temperature of the initial quenching medium.
In addition, it is preferable that calculating the amount of heat derived from the continuous casting slab within a preset time step based on the heat flow of the continuous casting slab and the initial quenching medium temperature includes:
calculating the average heat flow of the continuous casting billet by adopting an average heat flow calculation formula;
wherein, the average heat flow calculation formula is as follows:
wherein q is ave Average heat flow of the strand, q i The heat flow of each calculation grid preset on the continuous casting billet is calculated, and n is the number of the calculation grids;
calculating the heat led out from the continuous casting billet within a preset time step by adopting a first continuous casting billet derived heat calculation formula according to the average heat flow of the continuous casting billet;
wherein the calculation formula of the derived heat of the first continuous casting blank is as follows:
Q＝q ave ·2(a+b)L·Δt；
whereinQ is the heat derived from the slab, Q ave The average heat flow of the continuous casting billet is represented by a and b, the section thickness and the section width of the continuous casting billet are represented by a, L is the fixed length of the continuous casting billet, and delta t is a preset time step.
In addition, it is preferable that calculating the amount of heat derived from the continuous casting slab within a preset time step based on the heat flow of the continuous casting slab and the initial quenching medium temperature includes:
calculating the heat quantity led out from the continuous casting billet within a preset time step by adopting a second continuous casting billet derived heat quantity calculation formula according to the area of the calculation grid divided on the contact surface of the continuous casting billet and the quenching medium; wherein, the calculation formula of the second continuous casting billet derived heat is as follows:
wherein Q is the heat quantity derived from the continuous casting billet, and Q is the heat quantity derived from the continuous casting billet i Heat flow, delta S, for each calculation grid preset on the strand i In order to calculate the area of the grid, delta t is a preset time step, L is the fixed length of the continuous casting billet, and n is the number of the calculation grid.
In addition, it is preferable that the calculation formula of the amount of heat absorbed by the quenching medium is:
qw = Q · η; wherein Qw is partial heat which is conducted out from the continuous casting billet and absorbed by the quenching medium, and eta is a preset effective coefficient.
In addition, it is preferable that the calculating of the quenching medium temperature after the end of the preset time step based on the amount of heat absorbed by the quenching medium within the preset time step and the corresponding quenching medium temperature after the end of the previous preset time step includes:
calculating the temperature rise value of the quenching medium in the preset time step by adopting a quenching medium temperature rise calculation formula; wherein the calculation formula of the temperature rise of the quenching medium is as follows:
Δ T = Qw/(W × Cp); wherein the content of the first and second substances,
delta T is the temperature rise value of the quenching medium, qw is the partial heat which is led out from the continuous casting billet and absorbed by the quenching medium, W is the capacity of the quenching medium, and Cp is the specific heat of the quenching medium;
calculating the quenching medium temperature after the preset time step is finished through a quenching medium temperature calculation formula after the preset time step is finished; wherein the content of the first and second substances,
the calculation formula of the quenching medium temperature after the preset time step is ended is as follows:
Tw＝Tw1+△T；
wherein Tw is the temperature of the quenching medium after the preset time step is finished, tw1 is the temperature of the quenching medium corresponding to the beginning of the preset time step, and DeltaT is the temperature rise value of the quenching medium.
In addition, the preset initial quenching medium temperature is not more than 45 ℃; the temperature of the quenching medium is not more than 60 ℃ after the preset quenching is finished; the preset quenching temperature rise threshold value is not more than 20 ℃; and/or the quenching medium is water.
According to the technical scheme, the quenching process design method provided by the invention calculates the casting blank temperature field in the quenching process by using the accurate surface quenching calculation model (namely the application of the temperature field calculation model in the quenching process), calculates the quenching medium temperature at the end of quenching according to the given initial quenching medium temperature, the quenching medium capacity and the quenching time, so as to obtain the corresponding relation among the initial quenching medium temperature under different working conditions, the quenching medium temperature at the end of quenching and the quenching medium capacity, and quickly and accurately designs the capacity of the quenching medium in the quenching process according to the preset initial quenching medium temperature, the preset quenching medium temperature at the end of quenching and the limit condition of the preset quenching temperature rise threshold, so as to ensure the quenching effect. The method provided by the invention reflects the actual situation by accurately simulating the surface quenching process and considering the real-time change of the temperature of the quenching medium, and the calculation result is more reliable.
To the accomplishment of the foregoing and related ends, one or more aspects of the invention comprise the features hereinafter fully described. The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Further, the present invention is intended to include all such aspects and their equivalents.
Drawings
Other objects and results of the present invention will become more apparent and more readily appreciated as the same becomes better understood by reference to the following description taken in conjunction with the accompanying drawings. In the drawings:
FIG. 1 is a schematic flow diagram of a quench process design method according to an embodiment of the present invention;
fig. 2 is a graph of the trend of the temperature rise at different initial water temperatures and water capacities in example 1 according to the present invention.
In the drawings, the same reference numerals indicate similar or corresponding features or functions.
Detailed Description
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that such embodiment(s) may be practiced without these specific details.
Aiming at the problem that a reasonable design method of a groove type quenching process capable of accurately simulating the quenching process is lacked at present, a quenching process design method is provided.
Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
In order to illustrate the quenching process design method provided by the present invention, fig. 1 shows a flow of the quenching process design method according to an embodiment of the present invention; fig. 2 shows the trend of the temperature increase at different initial water temperatures and water capacities in example 1 according to the invention.
As shown in the figure 1 and the figure 2, the quenching process design method provided by the invention comprises the following steps:
s1, calculating the temperature of the quenching medium at the end of quenching according to the casting blank temperature field in the quenching process, the given initial quenching medium temperature, the given initial quenching medium capacity and the given quenching time.
As a preferred aspect of the present invention, the calculating of the quenching medium temperature at the end of quenching from the casting blank temperature field of the quenching process, the given initial quenching medium temperature, the given capacity of the quenching medium, and the quenching time includes:
a1, carrying out real-time tracking calculation on a temperature field in the quenching process of a continuous casting blank through a temperature field calculation model to obtain a continuously-changed casting blank temperature field;
a2, calculating the heat quantity led out from the continuous casting billet within a preset time step according to a casting billet temperature field, the temperature of an initial quenching medium and the heat exchange coefficient of the surface of the casting billet;
a3, calculating the heat absorbed by the quenching medium in the preset time step according to the heat derived from the continuous casting billet in the preset time step and a preset effective coefficient;
a4, calculating the temperature of the quenching medium after the preset time step is finished according to the heat absorbed by the quenching medium in the preset time step and the corresponding temperature of the quenching medium after the previous preset time step is finished;
and A5, repeating the steps A2 to A4 until the quenching is finished, and obtaining the temperature of the quenching medium at the end of the quenching.
As a preferred scheme of the invention, the temperature field calculation model calculates the temperature field of the continuous casting billet by adopting a conversion temperature and conversion enthalpy method, and comprises the following calculation formula:
differential simplified equation for heat transfer:
wherein rho is the density of the continuous casting billet, t is the heat transfer time, and lambda 0 Is the reference temperature T 0 The heat conductivity coefficient phi is the conversion temperature, and H is the enthalpy;
the calculation formula of enthalpy is:
wherein, T 0 Is an optional reference temperature, H 0 Is a corresponding referenceEnthalpy, L is the latent heat of solidification, c p (τ) is the specific heat at temperature τ, f s The solid phase ratio;
the conversion temperature and temperature corresponding relation formula is as follows:
wherein λ is 0 Is the reference temperature T 0 Thermal conductivity of (1); λ (t) is the thermal conductivity at temperature t.
As a preferable aspect of the present invention, the calculating the heat derived from the continuous casting slab within the preset time step according to the casting slab temperature field, the initial quenching medium temperature, and the heat transfer coefficient of the casting slab surface includes:
calculating the heat flow of the continuous casting billet according to the temperature field of the continuous casting billet and the heat exchange coefficient of the surface of the casting billet within a preset time step; wherein the heat exchange coefficient of the surface of the casting blank and the temperature of the quenching medium are related functions, and h = f (Tw); wherein h is the heat exchange coefficient of the surface of the casting blank, and Tw is the temperature of the quenching medium;
and calculating the heat quantity led out from the continuous casting billet within a preset time step according to the heat flow of the continuous casting billet and the temperature of the initial quenching medium.
And considering the balance between the heat released by the casting blank and the heat absorbed by the quenching medium in each preset time step, and considering the temperature rise of the quenching medium brought by the heat released by the continuous casting blank in each preset time step to determine the temperature of the real-time quenching medium, so that the temperature is used as the basis of heat transfer of the next preset time step, and the accuracy of a model calculation result is ensured and is closer to the actual condition.
As a preferred scheme of the invention, the boundary heat exchange in the quenching process of the continuous casting billet adopts a third boundary condition, and the third boundary condition is as follows:
q＝h*(Tsurface-Twater)；
and when the heat flow of the continuous casting billet in the first preset time step is calculated, the temperature of the last preset time step of the quenching medium is the temperature of the initial quenching medium.
Knowing the initial quenching medium temperature, the heat flow of the continuous casting billet in each preset time step can be calculated, and then the quenching medium temperature at the end of quenching is calculated finally.
As a preferred aspect of the present invention, calculating the amount of heat derived from the continuous casting slab in the preset time step based on the heat flow of the continuous casting slab and the temperature of the initial quenching medium includes:
calculating the average heat flow of the continuous casting billet by adopting an average heat flow calculation formula;
wherein, the average heat flow calculation formula is as follows:
wherein q is ave Average heat flow of the strand, q i The heat flow of each calculation grid preset on the continuous casting billet is calculated, and n is the number of the calculation grids;
calculating the heat led out from the continuous casting billet within a preset time step by adopting a first continuous casting billet heat led-out calculation formula according to the average heat flow of the continuous casting billet;
the calculation formula of the derived heat of the first continuous casting blank is as follows:
Q＝q ave ·2(a+b)L·Δt；
wherein Q is the heat output of the continuous casting billet, Q ave The average heat flow of the continuous casting billet is represented by a and b, the section thickness and the section width of the continuous casting billet are represented by a, L is the fixed length of the continuous casting billet, and delta t is a preset time step.
As a preferred aspect of the present invention, calculating the amount of heat derived from the continuous casting slab in the preset time step based on the heat flow of the continuous casting slab and the temperature of the initial quenching medium includes:
calculating the heat quantity led out from the continuous casting billet within a preset time step by adopting a second continuous casting billet derived heat quantity calculation formula according to the area of the calculation grid divided on the contact surface of the continuous casting billet and the quenching medium; wherein, the calculation formula of the second continuous casting billet derived heat is as follows:
wherein Q is the heat quantity derived from the continuous casting billet, and Q is the heat quantity derived from the continuous casting billet i Heat flow, delta S, for each calculation grid preset on the strand i In order to calculate the area of the grid, delta t is a preset time step, L is the fixed length of the continuous casting billet, and n is the number of the calculation grid.
The heat derived from the continuous casting billet can be calculated by adopting the two calculation modes.
In a preferred embodiment of the invention, the amount of heat absorbed by the quenching medium is calculated as:
qw = Q · η; wherein Qw is partial heat which is conducted out from the continuous casting billet and absorbed by the quenching medium, and eta is a preset effective coefficient.
As a preferable aspect of the present invention, calculating the temperature of the quenching medium after the end of the preset time step based on the amount of heat absorbed by the quenching medium within the preset time step and the corresponding temperature of the quenching medium after the end of the previous preset time step includes:
calculating the temperature rise value of the quenching medium in a preset time step by adopting a quenching medium temperature rise calculation formula; wherein, the calculation formula of the temperature rise of the quenching medium is as follows:
Δ T = Qw/(W × Cp); wherein the content of the first and second substances,
delta T is the temperature rise value of the quenching medium, qw is the partial heat which is led out from the continuous casting billet and absorbed by the quenching medium, W is the capacity of the quenching medium, and Cp is the specific heat of the quenching medium;
calculating the quenching medium temperature after the preset time step is finished through a quenching medium temperature calculation formula after the preset time step is finished; wherein, the first and the second end of the pipe are connected with each other,
the calculation formula of the quenching medium temperature after the preset time step is finished is as follows:
Tw＝Tw1+△T；
wherein Tw is the temperature of the quenching medium after the preset time step is finished, tw1 is the temperature of the quenching medium corresponding to the beginning of the preset time step, and DeltaT is the temperature rise value of the quenching medium.
S2, establishing a corresponding relation among the initial quenching medium temperature, the quenching medium temperature at the end of quenching and the quenching medium capacity.
The method is used for designing the capacity of the quenching medium in the quenching process of the continuous casting billet later by establishing the corresponding relation among different initial quenching medium temperatures, the quenching medium temperature at the end of quenching and the quenching medium capacity.
And S3, according to the corresponding relation, designing the capacity of the quenching medium in the quenching process of the continuous casting billet according to the preset initial quenching medium temperature, the preset quenching medium temperature at the end of quenching and the preset quenching temperature rise threshold value.
Wherein the preset quenching temperature rise threshold is a process reasonable value of the temperature difference between the quenching medium temperature at the end of the preset quenching and the preset initial quenching medium temperature.
As a preferable aspect of the present invention, the initial quenching medium temperature is preset to be not more than 45 ℃; the temperature of the quenching medium is not more than 60 ℃ when the preset quenching is finished; presetting a quenching temperature rise threshold value to be not more than 20 ℃; and/or the quenching medium is water.
Taking the quenching process of a water cooling tank as an example, the initial water temperature in the water cooling tank is not more than 45 ℃, the rising degree of the water temperature in the quenching process is not more than 20 ℃, and the water temperature is not more than 60 ℃ after the quenching is finished. According to the process design criteria, the process design of the cooling water capacity in the water cooling tank can be carried out on the basis of the accurate surface quenching calculation model, so that the quenching effect is ensured.
The following examples are presented to further illustrate the present invention so that those skilled in the art may better understand the advantages and features of the present invention.
Example 1:
taking the industrial production of continuous casting water cooling groove type quenching of small square billets in a certain factory as an example, wherein the section of the continuous casting billet is 180mm × 180mm, the length of a fixed length is 12m, the steel grade is 40Cr, and the process quenching time is 30s.
Under the two conditions that the initial water temperature in the water cooling tank at the beginning of quenching is 35 ℃ and 40 ℃, the temperature rise conditions under the conditions of different water capacities in the water cooling tank can be obtained by using the method provided by the invention (wherein the effective coefficient eta is 1), and the calculation result is shown in figure 2.
As can be seen from FIG. 2, under the condition of the same quenching time and the same initial water temperature, the temperature rise of the cooling water in the surface quenching process is reduced along with the increase of the water capacity in the water cooling tank, and the quenching effect is more ensured. In fig. 2, although the temperature rise of the initial water temperature of 40 ℃ is smaller than that of 35 ℃, the quenching effect of 35 ℃ is better when the water temperature after quenching at the initial water temperature of 40 ℃ is larger than that of 35 ℃ as a whole.
The process design criteria according to the invention: the rising degree of the water temperature in the cooling process is not more than 20 ℃, the water temperature after quenching is not more than 60 ℃, and the water capacity in the water cooling tank must be more than 4T according to the specific situation of the embodiment.
According to the quenching process design method provided by the invention, the casting blank temperature field in the quenching process is calculated by using the accurate surface quenching calculation model (namely the application of the temperature field calculation model in the quenching process), the quenching medium temperature at the end of quenching is calculated according to the given initial quenching medium temperature, quenching medium capacity and quenching time, so that the corresponding relation among the initial quenching medium temperature under different working conditions, the quenching medium temperature at the end of quenching and the quenching medium capacity is obtained, and the capacity of the quenching medium in the quenching process is quickly and accurately designed according to the preset initial quenching medium temperature, the preset quenching medium temperature at the end of quenching and the limit condition of the preset quenching temperature rise threshold, so that the quenching effect is ensured. The method provided by the invention reflects the actual situation by accurately simulating the surface quenching process and considering the real-time change of the temperature of the quenching medium, and the calculation result is more reliable.
The proposed quenching process design method according to the invention is described above by way of example with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that various modifications may be made to the design of the quenching process set forth above without departing from the spirit of the invention. Therefore, the scope of the present invention should be determined by the contents of the appended claims.
Claims (10)
1. A quenching process design method is characterized by comprising the following steps:
s1, calculating the temperature of a quenching medium at the end of quenching according to a casting blank temperature field in the quenching process, the given initial quenching medium temperature, the given initial quenching medium capacity and the given quenching time;
s2, establishing a corresponding relation among the initial quenching medium temperature, the quenching medium temperature at the end of quenching and the quenching medium capacity;
s3, according to the corresponding relation, designing the capacity of the quenching medium in the quenching process of the continuous casting billet according to a preset initial quenching medium temperature, a preset quenching medium temperature at the end of quenching and a preset quenching temperature rise threshold;
wherein the preset quenching temperature rise threshold is a process reasonable value of the temperature difference between the quenching medium temperature and the preset initial quenching medium temperature at the end of the preset quenching.
2. The method of claim 1, wherein the calculating the quenching medium temperature at the end of quenching according to the casting blank temperature field of the quenching process, the given initial quenching medium temperature, the given capacity of the quenching medium, and the quenching time comprises:
a1, carrying out real-time tracking calculation on a temperature field in the quenching process of a continuous casting blank through a temperature field calculation model to obtain a continuously-changed casting blank temperature field;
a2, calculating the heat quantity led out from the continuous casting billet within a preset time step according to the temperature field of the casting billet, the temperature of the initial quenching medium and the heat exchange coefficient of the surface of the casting billet;
a3, calculating the heat absorbed by the quenching medium in the preset time step according to the heat derived from the continuous casting billet in the preset time step and a preset effective coefficient;
a4, calculating the temperature of the quenching medium after the preset time step is finished according to the heat absorbed by the quenching medium in the preset time step and the corresponding temperature of the quenching medium after the previous preset time step is finished;
and A5, repeating the steps A2 to A4 until the quenching is finished, and obtaining the temperature of the quenching medium at the end of the quenching.
3. The quenching process design method according to claim 2,
the temperature field calculation model calculates the temperature field of the continuous casting billet by adopting a conversion temperature and conversion enthalpy method, and comprises the following calculation formula:
differential heat transfer simplified equation:
wherein rho is the density of the continuous casting billet, t is the heat transfer time, and lambda 0 Is the reference temperature T 0 The heat conductivity coefficient phi is the conversion temperature, and H is the enthalpy;
the calculation formula of enthalpy is:
wherein, T 0 Is an optional reference temperature, H 0 Is the corresponding reference enthalpy, L is the latent heat of solidification, c p (τ) is the specific heat at temperature τ, f s The solid phase ratio;
the conversion temperature and temperature corresponding relation formula is as follows:
wherein λ is 0 Is the reference temperature T 0 Thermal conductivity of (1); λ (t) is the thermal conductivity at temperature t.
4. The quenching process design method according to claim 2, wherein the calculating the heat quantity derived from the continuous casting billet within a preset time step according to the casting billet temperature field, the initial quenching medium temperature and the heat transfer coefficient of the casting billet surface comprises:
calculating the heat flow of the continuous casting billet according to the temperature field of the continuous casting billet and the heat exchange coefficient of the surface of the casting billet within a preset time step; wherein the heat exchange coefficient of the surface of the casting blank and the temperature of the quenching medium are related functions, and h = f (Tw); wherein h is the heat exchange coefficient of the surface of the casting blank, and Tw is the temperature of the quenching medium;
and calculating the heat quantity led out from the continuous casting billet within a preset time step according to the heat flow of the continuous casting billet and the temperature of the initial quenching medium.
5. The quenching process design method as claimed in claim 2, wherein the boundary heat exchange in the quenching process of the continuous casting billet adopts a third type of boundary conditions, and the third type of boundary conditions are as follows:
q＝h*(Tsurface-Twater)；
and when the heat flow of the continuous casting billet in the first preset time step is calculated, the temperature of the last preset time step of the quenching medium is the temperature of the initial quenching medium.
6. The quenching process design method of claim 4, wherein calculating the amount of heat derived from the continuous casting slab within a preset time step based on the heat flow of the continuous casting slab and the initial quenching medium temperature comprises:
calculating the average heat flow of the continuous casting billet by adopting an average heat flow calculation formula;
wherein, the average heat flow calculation formula is:
wherein q is ave Mean heat flow of the strand, q i The heat flow of each calculation grid preset on the continuous casting billet is calculated, and n is the number of the calculation grids;
calculating the heat led out from the continuous casting billet within a preset time step by adopting a first continuous casting billet derived heat calculation formula according to the average heat flow of the continuous casting billet;
wherein the calculation formula of the derived heat of the first continuous casting blank is as follows:
Q＝q ave ·2(a+b)L·Δt；
wherein Q is the heat quantity derived from the continuous casting billet, and Q is the heat quantity derived from the continuous casting billet ave The average heat flow of the continuous casting billet is represented by a and b, the section thickness and the section width of the continuous casting billet are represented by a, L is the fixed length of the continuous casting billet, and delta t is a preset time step.
7. The quenching process design method of claim 4, wherein calculating the amount of heat derived from the continuous casting slab within a preset time step based on the heat flow of the continuous casting slab and the initial quenching medium temperature comprises:
calculating the heat led out from the continuous casting billet within a preset time step by adopting a second continuous casting billet derived heat calculation formula according to the area of the calculation grid divided on the contact surface of the continuous casting billet and the quenching medium; wherein, the calculation formula of the second continuous casting billet derived heat is as follows:
wherein Q is the heat quantity derived from the continuous casting billet, and Q is the heat quantity derived from the continuous casting billet i Heat flow, delta S, for each calculation grid preset on the strand i In order to calculate the area of the grid, delta t is a preset time step, L is the fixed length of the continuous casting billet, and n is the number of the calculation grid.
8. The quenching process design method according to claim 2, characterized in that the calculation formula of the amount of heat absorbed by the quenching medium is:
qw = Q · η; wherein Qw is partial heat which is conducted out from the continuous casting billet and absorbed by the quenching medium, and eta is a preset effective coefficient.
9. The quenching process design method of claim 2, wherein calculating the quenching medium temperature after the preset time step is finished according to the heat absorbed by the quenching medium in the preset time step and the corresponding quenching medium temperature after the previous preset time step is finished comprises:
calculating the temperature rise value of the quenching medium in the preset time step by adopting a quenching medium temperature rise calculation formula; wherein the calculation formula of the temperature rise of the quenching medium is as follows:
Δ T = Qw/(W × Cp); wherein the content of the first and second substances,
delta T is the temperature rise value of the quenching medium, qw is the partial heat which is led out from the continuous casting billet and absorbed by the quenching medium, W is the capacity of the quenching medium, and Cp is the specific heat of the quenching medium;
calculating the quenching medium temperature after the preset time step is finished through a quenching medium temperature calculation formula after the preset time step is finished; wherein, the first and the second end of the pipe are connected with each other,
the calculation formula of the quenching medium temperature after the preset time step is ended is as follows:
Tw＝Tw1+△T；
wherein Tw is the temperature of the quenching medium after the preset time step is finished, tw1 is the temperature of the quenching medium corresponding to the beginning of the preset time step, and DeltaT is the temperature rise value of the quenching medium.
10. The quenching process design method according to claim 1,
the temperature of the preset initial quenching medium is not more than 45 ℃;
the temperature of the quenching medium is not more than 60 ℃ after the preset quenching is finished;
the preset quenching temperature rise threshold value is not more than 20 ℃; and/or the presence of a gas in the atmosphere,
the quenching medium is water.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1128182A (en) * | 1994-01-10 | 1996-08-07 | 梯品斯股份有限公司 | Intermediate thickness twin slab caster and inline hot strip and plate line |
| CN106825479A (en) * | 2017-03-23 | 2017-06-13 | 东北大学 | A kind of determination method of hot delivering technology of CC billets process quenching technology for surfaces cooling water flow |
| CN113174467A (en) * | 2021-03-23 | 2021-07-27 | 中冶南方连铸技术工程有限责任公司 | Method for predicting casting blank quenching structure and method for making casting blank quenching process |
| CN113361159A (en) * | 2021-05-31 | 2021-09-07 | 西安建筑科技大学 | Moving plate temperature field simulation method for jet impact quenching of nozzle |
| CN113935209A (en) * | 2021-09-28 | 2022-01-14 | 南京钢铁股份有限公司 | FLUENT-based simulation method for temperature field in roller-type continuous quenching process |
-
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- 2022-07-25 CN CN202210877215.6A patent/CN115383071A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1128182A (en) * | 1994-01-10 | 1996-08-07 | 梯品斯股份有限公司 | Intermediate thickness twin slab caster and inline hot strip and plate line |
| CN106825479A (en) * | 2017-03-23 | 2017-06-13 | 东北大学 | A kind of determination method of hot delivering technology of CC billets process quenching technology for surfaces cooling water flow |
| CN113174467A (en) * | 2021-03-23 | 2021-07-27 | 中冶南方连铸技术工程有限责任公司 | Method for predicting casting blank quenching structure and method for making casting blank quenching process |
| CN113361159A (en) * | 2021-05-31 | 2021-09-07 | 西安建筑科技大学 | Moving plate temperature field simulation method for jet impact quenching of nozzle |
| CN113935209A (en) * | 2021-09-28 | 2022-01-14 | 南京钢铁股份有限公司 | FLUENT-based simulation method for temperature field in roller-type continuous quenching process |
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