JP6252532B2 - Apparatus and method for setting target molten steel temperature at the end of converter blowing - Google Patents

Description

  The present invention provides a target molten steel at the end of converter blowing that sets a target molten steel temperature at the end of converter blowing in a secondary refining process in which molten steel blown in the converter is supplied to a continuous casting machine via a secondary refining device. The temperature setting device and the method thereof are suitable for setting a target molten steel temperature at the end of converter blowing by a computer having a calculation function, for example.

  The refining process for obtaining molten steel by decarburizing, removing impurities and adjusting the components of the molten iron discharged from the blast furnace is an important process of steelmaking. In such a refining process, in the secondary refining process in which the molten steel blown in the converter is supplied to the continuous casting machine via the secondary refining device, the molten steel temperature at the start of casting by the continuous casting machine is continuous. It needs to be higher than the required molten steel temperature at the start of casting in the casting machine. However, it is practically difficult to directly and continuously measure the temperature of molten steel in each process from the end of converter blowing to the continuous casting through the secondary refining process. Therefore, the molten steel temperature at the end of the converter blowing is important.

In the conventional converter blow control end control method, from the time of measurement by the sublance during the blowing to the end of the blowing, the molten steel temperature at the end of blowing and the carbon concentration at the end of blowing are set in advance for each steel type. Blowing conditions such as oxygen supply and cold material input are shown. In addition, each process after the end of converter blowing and the change in molten steel temperature during transportation are estimated by the operator from each process schedule, and the target value of the molten steel temperature at the end of blowing is corrected by the operator's judgment Is the actual situation. At that time, in order to avoid the actual molten steel temperature from becoming lower than the required molten steel temperature at the end of steel output due to variations in the temperature drop at the time of steel output, the target molten steel temperature at the end of converter blowing is set to the high temperature side. There is a case where it is corrected, which leads to an increase in the basic unit of converter blowing.
As a molten steel temperature control method at the end of converter blowing, Patent Document 1 below estimates the ladle temperature immediately before receiving steel from the converter, uses it to predict the temperature drop of steel output, The process processing time and the transport time between each process are predicted, and these are added to the molten steel temperature required at the start of continuous casting to determine the target molten steel temperature at the end of converter blowing.

Japanese Patent No. 3146907

However, in the method of setting the target molten steel temperature at the end of the converter blowing described in Patent Document 1, in the ladle thickness direction accompanying the temperature gradient inside the ladle refractory and the iron skin before the ladle becomes empty Therefore, there is a problem that an error occurs in the amount of heat extracted from the molten steel to the ladle after the steel is discharged, and the estimation accuracy of the molten steel temperature is lowered.
The present invention has been made paying attention to the above problems, for example, the temperature distribution in the thickness direction of the ladle according to the use status of the ladle, such as the ladle use history before the previous steelmaking. By calculating the state by continuous heat transfer calculation, it is possible to accurately determine the amount of heat removed from the molten steel after steel is discharged to the ladle, and it is therefore possible to set an appropriate target molten steel temperature at the end of converter blowing An object of the present invention is to provide an apparatus and a method for setting a target molten steel temperature at the end of converter blowing.

  In order to solve the above problems, according to one aspect of the present invention, a computer having an arithmetic processing function in a secondary refining process for supplying molten steel blown in a converter to a continuous casting machine through a secondary refining device. Is the target molten steel temperature setting device at the end of converter blowing, which sets the target molten steel temperature at the end of converter blowing, and sets the molten steel temperature at the end of converter blowing in heat transfer calculation The molten steel temperature setting unit, the ladle temperature distribution state calculation unit that calculates the temperature distribution state in the ladle thickness direction by continuous heat transfer calculation according to the use state of the ladle, and converter blowing Calculated by the molten steel temperature and ladle temperature distribution state calculation unit at the end of converter blowing set in the operation schedule and transportation schedule in each process from the end to the start of continuous casting and the molten steel temperature setting unit at the end of converter blowing By heat transfer calculation using temperature distribution in the ladle thickness direction The temperature difference between the molten steel temperature estimation unit that estimates the steel temperature and the molten steel temperature estimated at the molten steel temperature estimation unit at the start of continuous casting and the required molten steel temperature at the start of casting in the continuous casting machine is within the allowable range of the molten steel temperature difference. At the end of the converter blowing, when a certain value is added to the molten steel temperature at the end of the converter blowing according to the variation of the actual molten steel temperature drop with respect to the prediction, the target molten steel temperature is set at the end of the converter blowing A target molten steel temperature setting device at the end of converter blowing comprising a target molten steel temperature setting unit is provided.

  According to another aspect of the present invention, in a secondary refining process of supplying molten steel blown in a converter to a continuous casting machine through a secondary refining device, the converter is used using a computer having an arithmetic processing function. A method for setting a target molten steel temperature at the end of the furnace blowing, which sets a target molten steel temperature at the end of the blowing, which sets a molten steel temperature at the end of the converter blowing in the heat transfer calculation. A ladle temperature distribution state reading step for reading the temperature distribution state in the ladle thickness direction calculated by the ladle temperature distribution state calculation unit by continuous heat transfer calculation according to the use state of the ladle; Step of reading molten steel temperature and ladle temperature distribution status at the end of converter blowing and set in the operation schedule and transportation schedule and the molten steel temperature setting step at the end of converter blowing in each process from the end of converter blowing to the start of continuous casting In the ladle thickness direction read in Molten steel temperature estimation step for estimating the molten steel temperature by heat transfer calculation using the temperature distribution state, molten steel temperature estimated at the molten steel temperature estimation step at the start of continuous casting, and required molten steel temperature at the start of casting in the continuous casting machine When the temperature difference is within the allowable temperature difference range of the molten steel, the target molten steel at the end of the converter blowing is added to the molten steel temperature at the end of the converter blowing according to the variation of the actual molten steel temperature drop with respect to the prediction. A method for setting a target molten steel temperature at the end of converter blowing comprising a step of setting a target molten steel temperature at the end of converter blowing that sets the temperature.

  ADVANTAGE OF THE INVENTION According to this invention, the amount of heat removal from the molten steel after steel output to a ladle can be calculated | required correctly, and the target molten steel temperature at the time of completion | finish of converter blowing can be set by this.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows one Embodiment of the converter, the secondary refining apparatus, and the continuous casting machine to which the target molten steel temperature setting apparatus and its method of the converter blowing end of this invention were applied. It is a schematic block diagram of the target molten steel temperature setting apparatus at the time of the end of converter blowing constructed | assembled in the computer system of FIG. It is explanatory drawing of the molten steel temperature estimation performed in the molten steel temperature estimation part of FIG. It is a flowchart which shows the arithmetic processing for the target molten steel temperature setting at the time of the end of converter blowing performed with the computer system of FIG. It is explanatory drawing of the heat transfer calculation performed by the arithmetic processing of FIG. It is explanatory drawing of an effect | action of the target molten steel temperature setting apparatus at the time of the end of converter blowing in FIG. It is explanatory drawing of the effect of the target molten steel temperature setting apparatus at the time of completion | finish of the converter blowing of FIG. It is explanatory drawing of the effect of the conventional target molten steel temperature setting method at the time of the end of converter blowing.

The following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, arrangement, etc. of components. Is not specified as follows. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.
Hereinafter, an apparatus for setting a target molten steel temperature at the end of converter blowing and a method thereof according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a converter 1, a secondary refining device 2, and a continuous casting machine 3 to which the apparatus for setting a target molten steel temperature at the end of converter blowing and the method thereof according to this embodiment are applied. In the converter 1, primary refining (also referred to as blowing) is performed mainly for decarburization, and after the temperature and components are measured, the molten steel that has been subjected to the primary refining treatment is put into the ladle 4. The molten steel delivered to the ladle 4 is conveyed to the secondary refining device 2 after measuring the temperature and components. In the secondary refining apparatus 2, for example, secondary refining such as deoxidation, degassing, and component adjustment is performed, and the molten steel is conveyed to the continuous casting machine 3 while being accommodated in the ladle 4 and subjected to continuous casting. The series of secondary refining processes are monitored and controlled by a computer system (computer) 5 having a high-level arithmetic processing function.

  FIG. 2 is a block diagram of an apparatus for setting a target molten steel temperature at the end of converter blowing constructed in the computer system 5 of FIG. As described above, a preset molten steel temperature is required at the start of continuous casting. If the amount of molten steel temperature change (fall) in the secondary refining process can be predicted, the predicted value is added to the required molten steel temperature at the start of casting. Thus, the target molten steel temperature at the end of the converter blowing can be obtained. However, the molten steel temperature change amount (falling amount) in the secondary refining process requires the molten steel temperature at the end of the converter blowing, that is, the set molten steel temperature at the end of the converter blowing is the required molten steel at the start of casting. It is necessary to repeatedly calculate whether the temperature is satisfied. Accordingly, the computer system 5 is repeatedly used to set the target molten steel temperature at the end of converter blowing. The computer system 5 performs arithmetic processing discretely as is well known, but since a plurality of arithmetic processing can be executed in a very short time and with high density by an advanced arithmetic processing function, it is macroscopic. A plurality of arithmetic processes can be performed simultaneously.

  In this converter blowing target molten steel temperature setting device, in addition to the converter blowing end target molten steel temperature setting unit 6 for finally setting the target molten steel temperature at the end of converter blowing, the ladle temperature distribution A state calculation unit 7 is provided. The ladle temperature distribution state calculation unit 7 obtains ladle use status information from the ladle use status information unit 17 monitored in the computer system 5 and also sets the target molten steel temperature setting unit 6 at the end of the converter blowing. The molten steel temperature estimated in the molten steel temperature estimation part 8 provided in the inside is shared, and the temperature distribution state in the thickness direction of the ladle 4 is calculated by continuous heat transfer calculation described later. The thickness direction of the ladle 4 means the thickness direction of the wall or bottom of the ladle 4. The ladle temperature distribution state calculation unit 7 corrects the temperature of the ladle 4 to be calculated (estimated) and the temperature of the molten steel based on actually measured ladle temperature information and molten steel measured temperature information. Moreover, this ladle temperature distribution state calculation part 7 is a parameter which adjusts parameters, such as a heat transfer coefficient and heat conductivity used for the heat transfer calculation of a ladle temperature distribution, based on ladle measured temperature information and molten steel measured temperature information. An adjustment unit 7a is provided.

  On the other hand, the molten steel temperature estimation part 8 is a molten steel temperature drop amount calculating part 9 before calculating the molten steel temperature in the converter before completion of the converter blowing, and a molten steel temperature drop in the discharged steel. The amount of molten steel temperature drop calculation unit 10 for calculating the amount of molten steel, the amount of molten steel in the molten steel in the converter blowing and the amount of change in the molten steel due to the heat balance with the input secondary material Heat balance molten steel temperature change calculation unit 11 with, after the steel output to the secondary refining to calculate the amount of molten steel temperature drop after post-steeling and before secondary refining molten steel temperature drop calculation unit 12, during the secondary refining Molten steel temperature drop calculation unit 13 during secondary refining that calculates the temperature drop of the molten steel, and heat balance molten steel with the molten steel interior that calculates the amount of change in the molten steel temperature due to the heat balance with the molten steel interior during secondary refining Temperature change amount calculation unit 14, oxygen blown in secondary refining Reacting molten steel temperature change amount calculation unit 15 for calculating the amount of change in molten steel temperature due to the reaction, and calculating the temperature drop calculating amount for the molten steel temperature after secondary refining from the second refining to the start of casting 16 is configured.

  In calculating the temperature drop or change of the molten steel, the operation schedule and transportation schedule, especially the scheduled operation time (hours) and scheduled transportation time (hours) in each process from the end of the converter blowing to the start of continuous casting. Etc. are used. Among these, the heat balance molten steel temperature change ΔTa1 with the molten alloy iron and the input auxiliary material in the molten steel, the heat balance molten steel temperature change ΔTa2 with the molten steel interior material, and the reaction molten steel temperature change ΔTo with the blown oxygen are described above. Detailed description will be omitted. The molten steel temperature drop before pre-steel temperature calculation calculated by the molten steel temperature drop calculator 9 before the steel exit includes the temperature drop ΔTct of the molten steel due to heat removal during standby in the converter before the steel exit, And the heat transfer coefficient of the converter, the heat conductivity in the thickness direction of the converter, the heat transfer coefficient of the converter and the atmosphere, etc., the amount of drop in the molten steel temperature is calculated according to the waiting time for steel output.

  The molten steel temperature drop calculated by the molten steel temperature drop calculation unit 10 includes the molten steel temperature drop ΔTt due to heat removal during the steel output, the heat transfer coefficient of the molten steel and the converter, Using heat conductivity in the furnace thickness direction, converter and atmospheric heat transfer coefficient, heat transfer coefficient between molten steel and ladle, heat conductivity in ladle thickness direction, heat transfer coefficient between ladle and atmosphere Then, the amount of decrease in molten steel temperature is calculated according to the estimated required time for steel production. Further, in this embodiment, using the temperature distribution state in the ladle thickness direction, heat transfer calculation is performed according to the amount of molten steel in the ladle that changes during steel output, and the amount of decrease in molten steel temperature is calculated. To do. Moreover, the molten steel temperature fall amount calculation part 10 of this embodiment is similar to the parameter adjustment part 7a of the ladle temperature distribution state calculation part 7, and the heat transfer coefficient between the molten steel and the ladle and the ladle thickness direction. A parameter adjusting unit 10a for adjusting parameters such as the heat conductivity of the ladle and the heat transfer coefficient between the ladle and the atmosphere.

  The molten steel temperature drop after post-steeling and before secondary refining calculated by the molten steel temperature drop calculator 12 after post-steeling and before secondary refining includes the heat removal during standby until the measurement of the molten steel temperature and components after completion of steelmaking The amount of molten steel temperature drop ΔTtl due to heat transfer and the amount of molten steel temperature drop ΔTlr due to heat removal during conveyance between the secondary refining equipment after the end of steelmaking, heat transfer coefficient between the molten steel and ladle, heat conduction in the ladle thickness direction Using the heat transfer coefficient between the ladle and the atmosphere, the amount of drop in molten steel temperature is calculated by heat transfer calculation according to the estimated waiting time until temperature / component measurement and the estimated transfer time. Also, the molten steel temperature drop amount calculation unit 12 after steelmaking and before secondary refining of this embodiment is similar to the parameter adjustment unit 7a of the ladle temperature distribution state calculation unit 7, and the heat transfer coefficient between the molten steel and the ladle, the ladle It has a parameter adjusting unit 12a for adjusting parameters such as the thermal conductivity in the pan thickness direction, the ladle and the air heat transfer coefficient.

  The molten steel temperature drop during secondary refining calculated by the molten steel temperature drop calculator 13 during secondary refining includes the molten steel temperature drop ΔTr due to heat removal during secondary refining, and heat transfer between the molten steel and the ladle. Using the heat transfer coefficient, the heat conductivity in the ladle thickness direction, the heat transfer coefficient between the ladle and the atmosphere, etc., the amount of molten steel temperature drop corresponding to the expected time required for secondary refining is calculated by heat transfer calculation. calculate. Moreover, the molten steel temperature drop amount calculation part 13 in the secondary refining of this embodiment is similar to the parameter adjustment part 7a of the ladle temperature distribution state calculation part 7, and the heat transfer coefficient between the molten steel and the ladle, the ladle thickness direction. A parameter adjusting unit 13a for adjusting parameters such as the heat conductivity to the ladle and the heat transfer coefficient between the ladle and the atmosphere.

  The post-secondary refining molten steel temperature drop calculated by the secondary refining molten steel temperature drop calculation unit 16 includes a molten steel temperature drop ΔTrc due to heat removal during conveyance between the secondary refining device and the continuous casting machine. Using the heat transfer coefficient between the molten steel and ladle, the heat conductivity in the ladle thickness direction, the heat transfer coefficient between the ladle and the atmosphere, etc., the molten steel temperature according to the estimated time required for transport between secondary refining and continuous casting Is calculated by heat transfer calculation. Moreover, the molten steel temperature drop amount calculation part 16 after the secondary refining of this embodiment is similar to the parameter adjustment part 7a of the ladle temperature distribution state calculation part 7, and the heat transfer coefficient between the molten steel and the ladle, the ladle thickness direction. A parameter adjusting unit 16a for adjusting parameters such as the heat conductivity to the ladle and the heat transfer coefficient between the ladle and the atmosphere.

  FIG. 3 is an explanatory diagram of molten steel temperature estimation performed by the molten steel temperature estimation unit 8 of FIG. For example, when the molten steel temperature after the end of converter blowing is changed as shown in FIG. 3, the required molten steel temperature T1 at the start of continuous casting is determined in advance. Molten steel temperature drop ΔTct due to heat removal, molten steel temperature drop ΔTt due to heat removal during steel output, heat balance change in molten steel temperature ΔTa1 between the alloy iron and auxiliary materials in the molten steel Molten steel temperature drop ΔTtl due to heat removal during standby until the end of steel output, molten steel temperature drop ΔTlr due to heat removal during conveyance between the secondary refining equipment from the end of steel output, molten steel temperature drop ΔTr due to heat removal during secondary refining, If you know the heat balance molten steel temperature change ΔTa2 with the molten steel interior material, the reaction molten steel temperature change ΔTo with the blown oxygen, and the molten steel temperature drop ΔTrc due to heat removal during transfer from the secondary refining equipment to the continuous casting machine, Add them to the required molten steel temperature T1 at the start of continuous casting It can be obtained converter blowing end target molten steel temperature T0 by. However, as described above, the molten steel temperature drop amount (change amount) in each process cannot be calculated unless the molten steel temperature at the end of the converter blowing is given first. Therefore, the computer system determines the molten steel temperature drop (change) in each process while appropriately setting the molten steel temperature at the end of converter blowing, and subtracts them to obtain the molten steel temperature at the start of continuous casting. It repeatedly calculates whether or not the required molten steel temperature is met.

  FIG. 4 is a flowchart showing a calculation process for setting the target molten steel temperature at the end of converter blowing performed by the computer system 5. That is, this calculation process constitutes the target molten steel temperature setting unit 6 at the end of the converter blowing in FIG. This calculation process is executed by, for example, inputting a target temperature setting command at the end of converter blowing by an operator. First, in step S1, the ladle temperature distribution initial condition calculated by the ladle temperature distribution state calculation unit 7 and each Read process conditions. Here, the temperature distribution in the ladle thickness direction continuously calculated by the ladle temperature distribution state calculation unit 7 is read and set as the initial condition of the ladle temperature distribution in the heat transfer calculation, and then the heat transfer calculation Read the required (processing, waiting) time and transfer time of each process required for the process.

Next, the process proceeds to step S2, and the molten steel temperature at the end of converter blowing is temporarily set as the initial condition of the molten steel temperature in the heat transfer calculation from the end of converter blowing to the start of continuous casting described in FIG.
Next, the process proceeds to step S3 to calculate the molten steel temperature at the start of continuous casting by estimating the molten steel temperature by executing the heat transfer calculation from the end of the converter blowing described in FIG. 2 to the start of continuous casting.
Next, the process proceeds to step S4, and a molten steel temperature difference between the molten steel temperature at the start of continuous casting calculated at step S3 and the required molten steel temperature at the start of continuous casting is calculated.
Next, it transfers to step S5 and performs comparison with the molten steel temperature difference calculated by step S4, and the preset allowable molten steel temperature difference.

  Next, the process proceeds to step S6 to determine whether or not the molten steel temperature difference calculated in step S4 is within a preset allowable range. If the molten steel temperature difference is within the allowable range, the process proceeds to step S7. If not, that is, if the molten steel temperature difference is outside the allowable range, the process proceeds to step S2. When shifting to step S2, the molten steel temperature at the end of the converter blowing set in step S2 is corrected and set by the molten steel temperature difference. In this case, if the molten steel temperature at the start of continuous casting is lower than the required molten steel temperature at the start of continuous casting, the molten steel temperature at the end of converter blowing is corrected to be larger by the molten steel temperature difference, and the molten steel temperature at the start of continuous casting starts If it is higher than the required molten steel temperature, the molten steel temperature at the end of converter blowing is corrected to be smaller by the molten steel temperature difference. The specific correction amount can be determined by an existing optimization method such as a gradient method, but is not limited thereto.

In step S7, a constant value is added to the latest molten steel temperature at the end of the converter blowing in proportion to the magnitude of the variation in the actual molten steel temperature drop with respect to the prediction, and is set as the target molten steel temperature at the end of the converter blowing To do. Specifically, the actual molten steel temperature drop that uses the same secondary refining equipment is extracted from past performance data that is stored separately, and based on the extracted data, for example, the standard deviation (σ) varies. To do. In addition, 3σ or the like can be set as the above-described constant value and added to the calculated molten steel temperature at the end of the converter blowing. Here, how much additional value is given is determined by taking into consideration the risk range depending on the equipment status (the use status of ladle and secondary refining equipment, the degree of aging, etc.).
Next, the process proceeds to step S8, and returns after outputting a result of a series of arithmetic processing. As a result of the arithmetic processing, for example, a necessary molten steel temperature at the end of steelmaking or a necessary molten steel temperature at the end of secondary refining may be output as a guideline for actual operation.

  In this embodiment, the ladle temperature distribution state calculation unit 7 calculates the temperature distribution state in the ladle thickness direction by continuous heat transfer calculation using the measured temperature of the molten steel and the measured temperature of the inner wall surface of the ladle. (Estimation) is continued, and the molten steel temperature is estimated using this ladle temperature distribution state. At that time, it reflects the molten steel temperature change in the ladle at the time of past steelmaking, the time when the molten steel was charged, the waiting time of the empty ladle, the presence or absence of a lid, and the like. For example, if the temperature distribution inside the ladle wall as well as the inner wall surface temperature of the ladle can be taken into account, the amount of heat stored in the ladle immediately before receiving steel can be estimated more accurately, and the temperature drop of the molten steel after steel output It is possible to appropriately calculate (estimate) the amount. In this embodiment, the ladle is divided into each part of the bottom part, the wall part molten steel contact part, the wall part molten steel non-contact part, and the opening part, and the thickness of the heat insulating material is set for each part. For example, FIG. 5 is not in contact with the portion where the molten steel (including slag) is in contact with the ladle wall portion (the actual refractory layer is more complicated) composed of the refractory layer and the iron shell. The wall internal temperature of a part is shown typically. In the opening, the thickness of the heat insulating material is set only when the pan lid is hung. The heat transfer model of each divided part is a one-dimensional model in the thickness direction, and heat conduction and heat transfer are generated one-dimensionally and approximated as no heat conduction to different parts. In the radiation, the form factor is calculated from the relative arrangement of each part and the surface of the molten steel (including slag). Moreover, the amount of molten steel temperature fall is calculated based on the calculated heat removal amount, specific heat, and molten steel amount to each divided part of the ladle. In particular, at the time of outgoing steel, etc., the molten steel height in the ladle is discretely changed to the nodes between the portions according to the amount of molten steel, so that there is no temperature difference in the height direction at the same portion of the ladle wall. The heat transfer equation that constitutes the heat transfer model is a method of radiant heat transfer in a closed space and one-dimensional unsteady heat conduction. Calculate every time. If the heat storage amount of each element in each part in the initial state and the heat inflow / outflow from moment to moment are known, the temperature of each element at all times can be calculated.

  FIG. 6 is an explanatory diagram of the molten steel temperature and the temperature distribution in the ladle thickness direction calculated (estimated) by the target molten steel temperature setting device at the end of the converter blowing in FIG. In the figure, “40 mm from the inner wall” is an estimated temperature of a depth position of 40 mm from the ladle inner wall surface at the molten steel contact site, and “80 mm from the inner wall” is a depth position of 80 mm from the ladle inner wall surface at the molten steel contact site. In addition to this, the internal temperature of the wall is continuously estimated. The measured temperature of the molten steel described above is measured at the end of the converter blowing, at the end of steel production, at the start of secondary refining, and at the end of secondary refining. Moreover, the measured temperature of the ladle is obtained by measuring the surface temperature of the inner wall of the ladle in the state of the empty pan after continuous casting. In this embodiment, when the measured temperature of the molten steel and the measured temperature of the ladle are acquired, the calculated molten steel temperature and the ladle temperature are corrected to the measured temperature, and the estimated molten steel temperature and the estimated ladle temperature are In order for the temperature difference from the measured temperature to be within the allowable range, parameters caused by the respective temperature differences, such as the heat transfer coefficient between the molten steel and the ladle, the thermal conductivity in the ladle thickness direction, the ladle and the atmosphere Adjust parameters such as heat transfer coefficient. Therefore, for example, in FIG. 6, there is a temperature difference between the estimated molten steel temperature and the actually measured temperature at the previous calculation, and the estimated molten steel temperature and the actually measured temperature at the next calculation in which the molten steel temperature and parameters are adjusted accordingly. It matches well.

FIG. 7 represents the molten steel temperature error between the molten steel temperature calculated and estimated by the target molten steel temperature setting device at the end of converter blowing in FIG. The deviation σ in this example was 8.1 ° C. FIG. 8 shows the frequency of the molten steel temperature error between the molten steel temperature calculated and estimated by the conventional method for setting the target molten steel temperature at the end of converter blowing and the measured molten steel temperature. The deviation σ in this example was 10.4 ° C. Therefore, according to the converter molten steel target temperature setting apparatus at the end of the furnace blowing of this embodiment, it is possible to set the target molten steel temperature at the end of the converter blowing low by a small deviation of the molten steel temperature error. This makes it possible to reduce the converter blowing unit.
In this embodiment, the example in which the correction of the molten steel temperature and the ladle temperature and the adjustment of the parameters based on the measured molten steel temperature and the measured ladle temperature are performed a plurality of times in one secondary refining process is described. The correction of the pot temperature and the adjustment of the parameters may be performed once or more in one secondary refining process.

  As described above, in the apparatus for setting the target molten steel temperature at the end of the converter blowing in this embodiment and the method thereof, in the secondary refining process of supplying the molten steel blown in the converter to the continuous casting machine through the secondary refining apparatus. Then, the target molten steel temperature at the end of the converter blowing is set using the computer system 5 having an arithmetic processing function. At that time, the molten steel temperature at the end of the converter blowing in the heat transfer calculation is set in the molten steel temperature setting step S2 at the end of the converter blowing, and the ladle temperature distribution is obtained by continuous heat transfer calculation according to the use condition of the ladle. The temperature distribution state in the thickness direction of the ladle calculated by the state calculation unit 7 is read in the ladle temperature distribution state reading step S1. Then, at the molten steel temperature estimation step S3, the operation schedule and the transportation schedule in each process from the end of the converter blowing to the start of continuous casting and the end of the converter blowing at the end of the converter blowing set at the molten steel temperature setting step S2 The molten steel temperature and ladle temperature distribution state reading step S1 is used to estimate the molten steel temperature by heat transfer calculation using the temperature distribution state in the ladle thickness direction, and at the end of converter blowing, the target molten steel temperature setting step S4 When the molten steel temperature difference between the molten steel temperature at the start of continuous casting estimated at the molten steel temperature estimation step S3 and the necessary molten steel temperature at the start of casting in the continuous casting machine is within the allowable range of molten steel temperature in S7 A constant value is added to the molten steel temperature at the end of smelting according to the variation of the actual molten steel temperature drop with respect to the prediction, and the target molten steel temperature at the end of converter blowing is set. Therefore, for example, by calculating the temperature distribution state in the ladle thickness direction according to the ladle usage status such as the ladle usage history before the previous ladle, the molten steel after lathing is calculated. Therefore, the amount of heat removed from the ladle to the ladle can be accurately determined, so that an appropriate target molten steel temperature at the end of the converter blowing can be set. This also makes it possible to reduce the converter blowing unit.

Moreover, molten steel temperature estimation step S3 and the ladle temperature distribution state calculation part 7 correct | amend the temperature distribution to the ladle thickness direction based on the measured temperature information of the ladle obtained by measuring, and heat transfer calculation. Adjust the ladle parameters at. Thereby, since the amount of heat removal from the molten steel after the steel is further extracted to the ladle can be accurately obtained, the accuracy of the target molten steel temperature at the end of the converter blowing is improved.
Moreover, molten steel temperature estimation step S3 and ladle temperature distribution state calculation part 7 correct | amend molten steel temperature based on the measured temperature information of the molten steel obtained by measuring, and adjust the parameter of the ladle in heat-transfer calculation. . Thereby, since the amount of heat removal from the molten steel after the steel is further extracted to the ladle can be accurately obtained, the accuracy of the target molten steel temperature at the end of the converter blowing is improved.

Moreover, the molten steel temperature setting step S2 at the end of the converter blowing is the molten steel temperature difference between the molten steel temperature at the start of continuous casting estimated in the molten steel temperature estimation step S3 and the required molten steel temperature at the start of casting in the continuous casting machine. When the difference is outside the allowable range, the molten steel temperature corrected by the molten steel temperature difference is set as the molten steel temperature at the end of the converter blowing. Thereby, the setting of the target molten steel temperature at the time of completion | finish of converter blowing can be shortened.
It goes without saying that the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention-specific matters described in the appropriate claims from the above description.

1 Converter 2 Secondary refining equipment 3 Continuous casting machine 4 Ladle 5 Computer system (computer)
6 Target Molten Steel Temperature Setting Unit at the End of Converter Blowing 7 Ladle Temperature Distribution State Calculation Unit 7a Parameter Adjustment Unit 8 Molten Steel Temperature Estimation Unit 9 Molten Steel Temperature Drop Calculation Unit 10 before Rolling Out Steel Molten Steel Temperature Drop Calculation Unit 10a Parameter adjustment section 11 Heat balance molten steel temperature change calculation section with molten alloy iron and auxiliary auxiliary materials in molten steel 12 Molten steel temperature drop calculation section after steelmaking and before secondary refining 12a Parameter adjustment section 13 Molten steel temperature drop during secondary refining Quantity calculation part 13a Parameter adjustment part 14 Heat balance molten steel temperature change calculation part with molten steel interior inclusion 15 Reacted molten steel temperature change calculation part with blown oxygen 16 Molten steel temperature drop calculation part after secondary refining 16a Parameter adjustment part 17 Ladle usage information section

Claims (8)

A secondary refining process in which molten steel blown in the converter is supplied to a continuous casting machine via a secondary refining device, and a converter that sets the target molten steel temperature at the end of the converter blowing using a computer that has an arithmetic processing function A target molten steel temperature setting device at the end of blowing,
The molten steel temperature setting section at the end of converter blowing, which temporarily sets the molten steel temperature at the end of converter blowing as an initial condition of the molten steel temperature in heat transfer calculation,
Ladle temperature distribution state calculation unit that continues to calculate the temperature distribution state at each time in the ladle thickness direction by heat transfer calculation regardless of the presence or absence of molten steel in the ladle,
Operation schedule and transportation schedule in each process from the end of the converter blowing to the start of continuous casting, and the molten steel temperature at the end of the converter blowing set by the molten steel temperature setting unit at the end of the converter blowing and the ladle temperature distribution A molten steel temperature estimation unit that estimates the molten steel temperature at the start of final continuous casting by heat transfer calculation using the temperature distribution state at each time in the ladle thickness direction calculated by the state calculation unit,
Used when the molten steel temperature difference between the molten steel temperature at the start of final continuous casting estimated by the molten steel temperature estimation unit and the molten steel temperature required at the start of casting in the continuous casting machine is within the allowable range of molten steel temperature The actual molten steel temperature drop with the same secondary refining equipment is extracted from past performance data, and based on the extracted data, the standard deviation of the error with respect to the prediction of the performance data varies, and the converter blowing is completed and a converter blowing end target molten steel temperature setting unit for performing the addition of a constant value corresponding to the variation of molten steel temperature drop of the actual set to converter blowing end target molten steel temperature when the molten steel temperature A target molten steel temperature setting device at the end of converter blowing. The molten steel temperature estimation part and ladle temperature distribution state calculation part are:
2. The temperature distribution in the ladle thickness direction is corrected based on the measured temperature information of the ladle obtained by measurement, and the parameters of the ladle in the heat transfer calculation are adjusted. The target molten steel temperature setting device at the end of converter blowing. The molten steel temperature estimation part and ladle temperature distribution state calculation part are:
The converter blower according to claim 1 or 2, wherein the temperature of the molten steel is corrected and the parameters of the ladle in the heat transfer calculation are adjusted based on measured temperature information of the molten steel obtained by measurement. Target molten steel temperature setting device at the end of refining. The molten steel temperature setting section at the end of the converter blowing is a molten steel temperature difference between the molten steel temperature at the start of final continuous casting estimated by the molten steel temperature estimation section and the required molten steel temperature at the start of casting in the continuous casting machine. 4. The molten steel temperature corrected by the molten steel temperature difference when the molten steel temperature difference is outside the allowable range is set to the molten steel temperature at the end of the converter blowing. 5. Target molten steel temperature setting device at the end of converter blowing. A secondary refining process in which molten steel blown in the converter is supplied to a continuous casting machine via a secondary refining device, and a converter that sets the target molten steel temperature at the end of the converter blowing using a computer that has an arithmetic processing function A method for setting a target molten steel temperature at the end of blowing,
A molten steel temperature setting step at the end of converter blowing, which temporarily sets the molten steel temperature at the end of converter blowing as an initial condition of the molten steel temperature in heat transfer calculation;
Of the temperature distribution at each time in the thickness direction of the ladle to the thickness direction of the ladle calculated by the ladle temperature distribution calculator continues to calculate the heat transfer calculation or without the molten steel in the ladle A ladle temperature distribution state reading step for reading the temperature distribution state at each time ,
Operation schedule and transportation schedule in each process from the end of the converter blowing to the start of continuous casting, and the molten steel temperature at the end of the converter blowing and the ladle temperature distribution set in the molten steel temperature setting step at the end of the converter blowing A molten steel temperature estimation step for estimating the final molten steel temperature at the start of continuous casting by heat transfer calculation using the temperature distribution state at each time in the ladle thickness direction read in the state reading step;
Used when the molten steel temperature difference between the molten steel temperature estimated at the molten steel temperature estimation step at the start of final continuous casting and the molten steel temperature required at the start of casting in the continuous casting machine is within the allowable range of molten steel temperature The actual molten steel temperature drop with the same secondary refining equipment is extracted from past performance data, and based on the extracted data, the standard deviation of the error with respect to the prediction of the performance data varies, and the converter blowing is completed and a converter blowing end target molten steel temperature setting step of the setting to the converter blowing at the end target molten steel temperature by performing the addition of a constant value corresponding to the variation of molten steel temperature drop of the actual molten steel temperature when A method for setting a target molten steel temperature at the end of converter blowing. The molten steel temperature estimation step and ladle temperature distribution state calculation unit,
6. The temperature distribution in the ladle thickness direction is corrected based on the measured temperature information of the ladle obtained by measurement, and parameters of the ladle in the heat transfer calculation are adjusted. The method for setting the target molten steel temperature at the end of converter blowing described in 1. The molten steel temperature estimation step and ladle temperature distribution state calculation unit,
7. The converter blowing according to claim 5, wherein the temperature of the molten steel is corrected and the parameters of the ladle in the heat transfer calculation are adjusted based on measured temperature information of the molten steel obtained by measurement. How to set the target molten steel temperature at the end of refining. The molten steel temperature setting step at the end of the converter blowing is a molten steel temperature difference between the molten steel temperature at the start of the final continuous casting estimated in the molten steel temperature estimation step and the required molten steel temperature at the start of casting in the continuous casting machine. The molten steel temperature corrected by the molten steel temperature difference when the molten steel temperature difference is outside the allowable range of the molten steel is set as the molten steel temperature at the end of the converter blowing, according to any one of claims 5 to 7. Target molten steel temperature setting method at the end of converter blowing.

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