TWI827485B - Method for predicting temperature of molten steel within tundish - Google Patents

Abstract

A method for predicting a temperature of molten steel within a tundish is provided. The method includes a preparation step, a scheduling step, a parameter obtaining step, and a calculation step. The method utilizes multiple parameters obtained by the parameter obtaining step to perform calculations, thereby predicting the temperature of molten steel within the tundish during a casting process.

Description

Method for predicting the temperature of molten steel in separate steel tanks

The present invention relates to a method for predicting temperature, and in particular to a method for predicting the temperature of molten steel in a separate steel tank.

In the steelmaking process, it is mainly divided into three stages: converter/electric furnace, refining and casting.

After the converter blowing or electric furnace melting is completed, the molten steel is loaded into a steel drum and sent to the secondary refining equipment for reprocessing. After adjusting the temperature and composition, it is sent to the casting equipment for casting, and the liquid steel is solidified into Solid form factor required. The casting methods are divided into two types: mold casting and continuous casting. At present, most of the world's major large steelmaking plants use continuous casting, referred to as continuous casting.

In the continuous casting production process of the steelmaking process, the molten steel flows into the steel distribution tank (tundish) through the ladle, and finally enters the mold (mold), and then pulls out the mold. And gradually completely solidified into a cast embryo. During continuous casting, the temperature is measured in separate steel tanks as a basis for process operation adjustments. Generally, the temperature measurement mainly uses paper tube temperature measuring rods. When the remaining tonnage of the molten steel in the steel drum is different, the temperature is measured 2 to 4 times to measure the temperature of the molten steel in the steel channel. The temperature measurement can be manual or mechanical. for it.

The temperature of the molten steel has a great influence on the quality of the casting blank. If the temperature of the molten steel is too high, the chances of explosion, segregation, defects, etc. of the molten steel during casting increase. If the temperature of the molten steel is too low, problems such as blockage of the dipping pipe and failure to open the gate of the steel drum will occur. Generally, the molten steel temperature is cast at a temperature higher than the target value, and the pouring speed is reduced when the temperature is too high. However, this will increase heating costs, reduce productivity, and often lead to a decrease in quality. The heating cost saved by reducing the superheat temperature is extremely considerable, so it is necessary to maintain the temperature control of the molten steel within a reasonable range.

In addition, during the continuous casting process, there are occasional abnormal conditions, such as: the ladle waits for too long on the turntable, abnormal single-channel casting, low temperature of the molten steel, slowdown, etc., resulting in low temperature of the molten steel in the component steel channel. However, solidification cannot achieve the function of continuous casting and affects the scheduling of the next furnace of molten steel. Furthermore, the temperature of the molten steel in the separate steel channel will also affect the quality of the produced casting blanks. Therefore, the real-time measurement of the temperature of the liquid steel in the separate steel channel Mastery is very important. If the temperature changes of the molten steel in the sub-channels can be properly grasped, it can assist the operator in adjusting the casting parameter settings, especially the control of the flow rate of the molten steel.

The current traditional method usually takes factors such as whether the steel drum is covered, the waiting time for the empty drum to be turned around, the waiting time for continuous casting, the size of the steel blank, the specifications of the steel product, and the actual measured temperature of the molten steel in the steel channel, and then according to the The operator determines the casting parameters for continuous casting. However, this method often relies on the personal experience of the operator, so there are often human differences, and if the temperature measurement results have errors, it may affect the pouring speed setting, misjudge the barrel of molten steel to be offline early, causing waste, or even the actual temperature of the molten steel. It is too low, and when it is discovered, it is too late to replace it, resulting in the undesirable situation of solidification of molten steel and breakage of the cast.

If the molten steel temperature during the continuous casting process can be accurately predicted, it will be of obvious help to control the continuous casting operation and the quality of the steel blank. Therefore, in order to overcome the shortcomings and deficiencies in the prior art, it is necessary for the present invention to provide an improved method for dividing the temperature of molten steel in a steel tank, so as to solve the problems existing in the above conventional technology.

The purpose of the present invention is to propose a method for predicting the temperature of molten steel in a separate steel tank, which includes: a preparation step, a scheduling step, a parameter acquisition step and a calculation step. In the preparation step, a steel drum and a steel trough are provided. The steel drum is used to contain molten steel for refining operations, and the steel trough is used to pour the molten steel from the steel drum for casting operations after the refining operation. Put it into the divided steel channel and then pour it into the casting mold. In the scheduling step, the refining completion time point when the refining operation is completed and the current time point when the casting operation is performed are obtained. In the parameter acquisition step, the following parameters are acquired: the temperature of the molten steel in the steel drum at the refining completion time point is acquired; the first stored heat amount of the steel drum at the current time point is acquired, and the molten steel temperature at the refining completion time point is acquired. The second heat storage of the steel drum; obtain the first temperature drop rate caused by the top slag surface of the molten steel in the steel drum and the second temperature drop rate caused by the shell of the steel drum; and obtain the liquid steel from the steel drum. The temperature drop produced when the barrel is poured into the steel tank. In the calculation step, calculation is performed based on the plurality of parameters to predict the temperature of the molten steel in the separate steel channels at the current time point. The above scheduling steps, parameter acquisition steps and calculation steps are executed by the computer.

In some embodiments, the calculation formula used in the above operation steps is: Among them, T _TD is the temperature of the molten steel in the sub-channel, T _Re is the temperature of the molten steel in the ladle at the time when refining is completed, HeatLD _cc is the first heat storage amount, HeatLD _Re is the second heat storage amount, and M _LD is the refining time. The weight of the molten steel in the ladle at the completion time point, c is the specific heat value of the molten steel, Δt is the time difference between the refining completion time point and the current time point, R _shell is the second temperature drop rate, and R _slag is the second temperature drop rate. A temperature drop rate, ΔT _LD-TD is the temperature drop produced when molten steel is poured from the steel drum into the steel distribution tank.

In some embodiments, the first heat storage capacity and the second heat storage capacity will decrease as the number of times the steel drum is used increases. The weight of refractory materials increases.

In some embodiments, the second temperature drop rate increases as the outer shell temperature of the steel drum increases, and the outer shell temperature of the steel drum increases as the number of times the steel drum is used increases.

In some embodiments, the above-mentioned first temperature drop rate increases as the temperature of the top slag surface of the molten steel in the ladle increases.

In some embodiments, the first temperature drop rate when the top of the steel drum is not covered is greater than the first temperature drop rate when the top of the steel drum is covered.

In some embodiments, the temperature drop of the above-mentioned steel ladle when it contains molten steel for the first time is greater than the temperature drop of the steel ladle when it does not contain molten steel for the first time.

In some embodiments, the above-mentioned method for predicting the temperature of the molten steel in the sub-tank further includes: an output display step and an early warning step. In the output display step, the temperature of the molten steel in the sub-channel is displayed on the display screen of the computer. In the pre-warning step, the temperature of the molten steel in the branching channel is compared with the set temperature, so as to issue an alarm when the temperature of the molten steel in the branching channel is lower than the set temperature. The above-mentioned pre-warning step is executed by the computer.

In some embodiments, the above-mentioned set temperature is the solidification temperature of the molten steel plus the buffer temperature, and the above-mentioned buffer temperature is associated with the steel type of the molten steel.

In some embodiments, the above-mentioned method for predicting the temperature of the molten steel in the sub-tank further includes: a suggestion step. In the recommended steps, the casting speed of the casting operation is adjusted according to the temperature of the molten steel in the sub-channel. In the recommended procedure, the casting speed decreases as the temperature of the molten steel in the split channel increases. The recommended steps above are performed by a computer.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings.

Embodiments of the present invention are discussed in detail below. It is to be appreciated, however, that the embodiments provide many applicable concepts that can be embodied in a wide variety of specific contexts. The embodiments discussed and disclosed are for illustration only and are not intended to limit the scope of the invention. The terms "first", "second", ..., etc. used in this article do not specifically refer to the order or order, but are only used to distinguish components or operations described with the same technical terms.

Figure 1 is a flow chart of a method for predicting the temperature of molten steel in a separate steel tank according to an embodiment of the present invention. As shown in Figure 1, the method for predicting the temperature of the molten steel in the sub-tank includes a preparation step S1, a scheduling step S2, a parameter acquisition step S3 and a calculation step S4. Among them, the scheduling step S2, the parameter acquisition step S3 and the operation step S4 are executed by a computer. The computer of the present invention can be an industrial computer, a distributed computer, a server, a cloud server or various electronic devices with computing capabilities. The present invention is not limited to this. Computer communication is connected to the relevant equipment of the steelmaking process to obtain the steelmaking process schedule time. The operation of each step will be explained in detail below.

In the preparation step S1, a steel ladle (ladle) and a steel dividing tank (liquid steel distributor (tundish)) are provided. The steel drum is a high-temperature-resistant insulated container with a steel iron shell on the outer wall and refractory material on the inner layer. During the refining stage of the steelmaking process, steel drums are used to contain high-temperature molten steel for refining operations. In the casting stage after the refining operation, the molten steel flows into the sub-trough through the steel drum. In other words, the steel dividing trough is used for casting operations after the refining operation, so that molten steel is poured from the ladle into the steel dividing trough and then poured into the casting mold.

In the scheduling step S2, the steelmaking process schedule time is obtained to obtain the refining completion time point when the refining operation is completed and the current time point when the casting operation is performed.

In the parameter acquisition step S3, multiple parameters required for the operation step S4 are acquired, including but not limited to: (a1) the temperature of the molten steel in the steel drum at the time point when refining is completed; (a2) the temperature of the molten steel at the current point in time. The first heat storage amount of the steel drum; (a3) The second heat storage amount of the steel drum at the time when refining is completed; (a4) The first temperature drop rate caused by the top slag surface of the molten steel in the steel drum; (a5 ) The second temperature drop rate caused by the outer shell of the steel drum; (a6) The temperature drop produced when molten steel is poured from the steel drum into the separate steel tank.

Specifically, the main reasons for the heat loss of molten steel are the heat loss caused by the heat absorption of the steel drum itself, the heat loss from the convection and radiated heat of the steel drum shell to the environment, and the convection and radiated heat from the slag surface on the top of the steel drum to the environment. of heat loss. The above parameters (a2) and parameter (a3) consider the heat loss caused by the heat absorption of the steel drum itself. The above parameter (a5) considers the heat loss from the convection and radiation heat of the ladle shell to the environment. The above-mentioned parameter (a4) considers the heat dissipation from the slag surface on the top of the ladle to the environment by convection and radiation.

Parameter (a1): The temperature of the molten steel in the steel drum at the time when refining is completed, which can be detected through the temperature measuring element. The computer communication is connected to the temperature measuring element, so the computer can obtain the parameter (a1). For example, at the time when refining is completed, the temperature measuring rod is penetrated into the molten steel slag surface of the steel drum through the paper tube to measure the temperature of the molten steel in the steel drum at the time when refining is completed.

The parameter (a2): the first heat storage amount of the steel drum at the current time point and the parameter (a3): the second heat storage amount of the steel drum at the refining completion time point can be obtained through a conversion relationship.

Specifically, the above-mentioned conversion relationship is about the conversion relationship between the time after the steel drum contains the molten steel and the heat absorption and continued heat of the steel drum itself. Therefore, the specific time point (i.e., the current time point, the refining completion time) can be time point) and enter the above conversion relationship to obtain the heat storage amount of the steel drum corresponding to that specific time point. In embodiments of the present invention, the above conversion relationship can be obtained through thermodynamic fluid dynamics simulation software or through statistical calculation based on historical process data. FIG. 2 is an illustrative relationship diagram illustrating the conversion relationship of the heat storage amount of the ladle according to the embodiment of the present invention. Curve C1 in Figure 2 shows an example relationship between the change of heat absorption degree of the ladle itself with time. It should be noted that the example relationship shown in FIG. 2 is only an illustration, and the present invention is not limited thereto. The time of 0 on the The time difference between steel time points is used to obtain parameter (a2). For example, if the tapping time point is 0:39, the refining completion time point is 1:57, the casting start time is 2:14, and the current time point is 2:39, then the refining completion time point and the tapping time can be The time difference between the points (78 minutes) is substituted into the above conversion relationship to obtain parameter (a3), and the time difference between the current time point and the tapping time point (120 minutes) can be substituted into the above conversion relationship to obtain Find parameter (a2).

The heat loss caused by the heat absorption of the steel drum depends on the thermal state of the steel drum, that is, the temperature distribution of the iron shell and refractory materials of the steel drum. The thermal state of the steel drum will be affected by the time and space of the molten steel. Bucket wait turnaround time impact. As shown in Figure 2, the heat absorption rate of the molten steel absorbed by the steel drum itself will gradually slow down as the longer the steel connection time is, the more saturated the heat accumulation in the drum body will be.

In addition, the heat storage of the steel drum is also related to the weight and specific heat of the steel drum's steel shell and the refractory material in the drum, and the temperature of the steel drum's shell and refractory material at that time. The weight of the refractory material in the outer shell and the barrel is determined by the size design of the steel barrel, and the weight of the refractory material is related to the number of times the steel barrel is used. After each round of steel barrels contains molten steel, the thickness of the refractory material shell decreases between 0.3~0.8(mm/time). At that time, the temperature of the shell and refractory material of the steel drum was related to the number of times the steel drum was used and the time it held the molten steel. The time it took to hold the molten steel should be less than 3 hours. Therefore, the first heat storage amount of parameter (a2) and the second heat storage amount of parameter (a3) will decrease as the number of times the ladle is used increases. Furthermore, the first heat storage amount of parameter (a2) and the second heat storage amount of parameter (a3) will increase as the weight of the shell of the steel drum and the refractory material in the drum increases.

Parameter (a5): The second temperature drop rate caused by the shell of the steel drum is based on the heat loss of the convection and radiation heat from the shell of the steel drum to the environment. It is related to the current temperature of the shell of the steel drum (i.e. the drum shell temperature). Parameter (a5) can be expressed by the following formula (1): (1) Temperature drop rate = heat loss per unit time/(weight of molten steel * specific heat of molten steel), where It is related to the convection heat of the ladle shell, where Related to radiant heat from the ladle.

Among them, R _shell is the parameter (a5), h _w is the convective heat transfer coefficient of the barrel shell (can be obtained by looking up the table or performing statistical calculation based on historical data), A _w is the surface area of the barrel shell, and T _w is the temperature of the barrel shell (can be The current temperature of the shell of the steel drum at the time when refining is completed is detected through a temperature measuring element), T _surr is the ambient temperature, is the emissivity of the barrel shell (can be obtained through table lookup or experimental measurement (measure a sample with a determined temperature using an emissivity measuring instrument)), is the Stefan-Boltzmann constant ( ), M _LD is the weight of the molten steel in the ladle at the time when refining is completed, and c is the specific heat value of the molten steel.

Through actual measurement and theoretical calculation, it can be found that the shell temperature of the steel drum is highly positively correlated with the number of times the steel drum is used, and the relationship can be almost linear. The reason is that the thickness of the refractory material on the inside of the steel drum will gradually decrease with the number of uses. After each round of the steel drum is filled with molten steel, the thickness of the refractory material on the inside of the steel drum will decrease by about 0.3~0.8 (mm/time) . Thin refractory materials have poor thermal insulation capabilities, making it easier for heat to escape, which is reflected in an increase in barrel shell temperature. In addition, the second temperature drop rate caused by the shell of the steel drum will also change due to the size of the steel drum and the shape design of the shell. The value range of the second temperature drop rate caused by the shell of the steel drum is generally within 0.05~ 0.5℃/min.

It can be known from the above that the second temperature drop rate will increase as the outer shell temperature of the steel drum increases, and the outer shell temperature of the steel drum will increase as the number of times the steel drum is used increases.

Parameter (a4): The first temperature drop rate caused by the top slag surface of the molten steel in the steel drum is based on the convection and radiated heat loss of the slag surface on the top of the steel drum to the environment. It is related to the heat loss of the steel drum. The current temperature of the top slag surface (that is, the top slag surface temperature) is related. Parameter (a4) can be expressed by the following formula (2): (2) Among them It is related to the convective heat on the slag surface at the top of the ladle, where It is related to the heat radiated from the slag surface on the top of the ladle.

Among them, R _slag is the parameter (a4), h _slag is the slag surface convection heat transfer coefficient (can be obtained by looking up the table or making statistical calculations based on historical data), A _slag is the slag surface area (can be obtained by shooting with a camera) obtained), T _slag is the slag surface temperature (can be detected through a temperature measuring element (such as a thermal imager)), T _surr is the ambient temperature, is the slag surface emissivity (can be obtained by looking up the table), is the Stefan-Boltzmann constant, M _LD is the weight of the molten steel in the ladle at the time when refining is completed, and c is the specific heat value of the molten steel.

The first temperature drop rate R _slag caused by the slag surface on the top of the steel drum is caused by the steelmaking slag on the top of the molten steel in the steel drum. Natural convection and radiation transfer heat to the environment. The temperature of the slag surface on the top of the steel drum is , actually measured with a thermal imaging camera, most of the temperature is 600~800℃. If the top cover of the steel drum is added, the temperature of the top cover is reduced to 150~250℃. The temperature drop rate of molten steel caused by the slag surface varies greatly depending on the slag surface area, slag surface temperature and whether it is capped. If it is not capped, it is generally between 0.1~0.4℃/min. If it is capped, Then it is between 0.01~0.03℃/min.

It can be seen from the above that the first temperature drop rate will increase as the temperature of the top slag surface of the molten steel in the ladle increases. Moreover, the first temperature drop rate when the top of the steel drum is not covered is greater than the first temperature drop rate when the top of the steel drum is covered.

Among them, parameter (a6): the temperature drop generated when the molten steel is poured from the steel drum into the steel distribution tank. After the molten steel flows from the ladle into the continuous casting sub-trough, part of the heat will be absorbed by the sub-trough, causing the temperature of the molten steel to drop again. This heat absorption is related to the size structure and heat transfer characteristics of the sub-channel (refractory properties of the sub-channel), and because after each continuous casting of the sub-channel, regardless of the degree of loss, the contact steel will definitely be reformed. On the surface of the liquid side, the divided steel trough does not have the phenomenon mentioned above that the increase in the use of the steel drum will cause the refractory material to gradually wear out and cause the heat absorption characteristics to change. In addition, it was also found that the temperature drop of the steel drum when it contained molten steel for the first time was greater than the temperature drop of the steel drum when it was not the first time of receiving molten steel. Regarding the temperature drop of parameter (a6), statistics and heat transfer theory can be used for different sub-tanks to calculate the degree of temperature drop when the corresponding molten steel is poured from the steel drum into the sub-tank, thus Accordingly, the parameter (a6) is obtained. The temperature drop of parameter (a6) is generally between 10~40℃.

Please return to FIG. 1 . In the calculation step S4 , calculation is performed based on the plurality of parameters obtained in the parameter acquisition step S3 to predict the temperature of the liquid steel in the separate steel channels at the current time point. . Among them, the calculation formula used in operation step S4 is expressed by the following formula (3): (3) Among them, T _TD is the temperature of the molten steel in the separate steel channel. T _Re is the parameter (a1), which is the temperature of the molten steel in the ladle at the time when refining is completed. HeatLD _cc is parameter (a2), which is the first heat storage amount of the ladle at the current time point. HeatLD _Re is parameter (a3), which is the second heat storage amount of the ladle at the time when refining is completed. M _LD is the weight of the molten steel in the ladle at the time when refining is completed. c is the specific heat value of molten steel. Δt is the time difference between the refining completion time point and the current time point. R _shell is parameter (a5), which is the second temperature drop rate caused by the shell of the steel drum. R _slag is parameter (a4), which is the first temperature drop rate caused by the top slag surface of the molten steel in the steel drum. ΔT _LD-TD is the parameter (a6), which is the temperature drop generated when the molten steel is poured from the steel drum into the separate steel tank.

Among them, M _LD (the weight of the molten steel in the steel drum at the time when refining is completed) can be subtracted from the total weight of the steel drum at the time when refining is completed (the weight of the empty steel drum + the weight of the molten steel). Obtained from the weight of the empty barrel. Among them, c (the specific heat value of the molten steel) is related to the steel type of the molten steel. In other words, c (the specific heat value of the molten steel) will change with the different steel types of the molten steel.

For example, if the weight M _LD of the molten steel is 150ton, the specific heat c of the molten steel is 0.68 J/g°C, the temperature T _Re of the molten steel in the steel drum at the time when refining is completed is 1617°C, and the temperature of the steel drum at the current time point is The first heat storage HeatLD _cc is 15083MJ, the second heat storage HeatLD _Re of the steel drum at the refining completion time point is 14152MJ, the time difference Δt between the refining completion time point and the current time point is 42min, the barrel body of the steel drum The second temperature drop rate R _shell caused by the shell is 0.2°C/min, and the first temperature drop rate R _slag caused by the top slag surface of the molten steel in the steel drum is 0.02°C/min. The molten steel is poured from the steel drum. The temperature drop ΔT _LD-TD produced when dividing the steel channel is 29℃, then the temperature T _TD of the liquid steel in the dividing steel channel is 1569.7(℃)=1617-[(15083- 14152)/(150*0.68)]-42(0.2 +0.02)-29. Comparing the temperature T _TD (1569.7°C) of the sub-channel molten steel with the actual measured temperature (1575°C), the difference between the two is only 5.3°C, which is quite close and can be used in practice.

Figure 3 is a comparison chart C2 between the predicted temperature and the measured temperature according to an embodiment of the present invention. The comparison chart C2 includes multiple data points, and the value of each data point on the vertical axis is the prediction of the continuous casting molten steel temperature. temperature, and the value of each data point on the horizontal axis is the actual measured temperature of the continuous casting molten steel. Comparing the data in Figure C2, after collecting the real historical data of the steelmaking plant and filtering out the heats with obviously unreasonable abnormal data or missing fields, the method of the present invention is used to predict the temperature of the liquid steel in the steel splitting tank. , by conducting backtesting on more than 500 furnace data, it can be obtained that the difference between the predicted temperature and the actual measured temperature of the continuous casting molten steel is within the range of ±10°C, which can reach a consistency of more than 98%. Since in the steelmaking process, the temperature of the molten steel is usually in the range of 1500~1600°C, the error range of ±10°C is quite accurate, which means that the temperature of the molten steel predicted by the method of the present invention for predicting the temperature of the molten steel in the separate steel tanks It is very close to the actual measured temperature and has extremely high practical value.

Table 1 shows the test results of randomly selecting one actual production heat in a single day from the above 500 furnace data. It can be found that the molten steel temperature predicted by the method of the present invention for predicting the temperature of molten steel in a separate steel tank Very close to the actual measured temperature. Heat Actual temperature (℃) Predicted temperature (℃) Measured temperature - predicted temperature 1 1536 1532 4 2 1556 1557 -1 3 1575 1570 5 4 1561 1552 9 5 1539 1543 -4 6 1548 1546 2 7 1574 1566 8 8 1568 1570 -2 9 1565 1565 0 10 1582 1573 9 11 1566 1573 -7 12 1575 1572 3 13 1562 1552 10 14 1557 1549 8 15 1509 1511 -2 16 1518 1515 3 17 1520 1514 6 18 1521 1515 6 19 1558 1554 4 20 1560 1565 -5 Table 1 Comparison table of predicted temperature and measured temperature

Figure 4 is a flow chart of a method for predicting the temperature of molten steel in a separate steel tank according to an embodiment of the present invention. The method shown in Figure 4 for predicting the temperature of the liquid steel in the steel dividing tank is similar to the method shown in Figure 1 for predicting the temperature of the liquid steel in the steel dividing tank. The difference is that the method shown in Figure 4 is used to predict the temperature of the liquid steel in the steel dividing tank. The method of measuring the temperature of molten steel in the tank also includes an output display step S5, a warning step S6 and a suggestion step S7. Among them, the output display step S5, the warning step S6 and the suggestion step S7 are executed by the computer.

In the output display step S5, the temperature of the molten steel in the sub-channel calculated in the operation step S4 is displayed on a computer display screen or a human-machine interface for the operator to view and perform subsequent adjustment operations accordingly. For example, if an abnormal temperature of the molten steel in the steel branching channel is found, the operator can make adjustments in advance in response to the process abnormality to prevent the steelmaking process from affecting the scheduling of the next furnace of molten steel due to abnormal conditions.

In the early warning step S6, the temperature of the liquid steel in the branching channel calculated in the operation step S4 is compared with a set temperature. If the temperature of the liquid steel in the branching channel is lower than the set temperature, an alarm is issued to provide the operator with the opportunity to judge whether to advance Offline reference.

In the early warning step S6, the set temperature is the solidification temperature of the molten steel plus the buffer temperature. The buffer temperature is related to the steel type of the molten steel. The buffer temperature is generally between 5 and 15°C. The solidification temperature can be a preset value or available. The value set by the operator. For example, if the solidification temperature is 1529°C and the buffer temperature is 10°C, when the temperature of the molten steel in the sub-channel calculated in step S4 is lower than 1539°C, an alarm will be issued to remind the operator of the sub-channel. If the temperature of the molten steel is too low, it may solidify at any time and cause casting blockage. It is necessary to immediately prepare another bucket of molten steel with a high enough temperature to continue the casting.

In the suggestion step S7, a recommended value of the casting speed of the casting operation is provided based on the molten steel temperature of the sub-channel calculated in the calculation step S4, as a reference for the operator to judge and adjust the casting speed. Regarding the recommended value of the casting speed, statistics and theoretical calculations can be used based on historical process data to find the optimal value of the casting speed corresponding to the temperature of the molten steel in the scored channel, and thus the recommended value of the casting speed can be obtained. In other words, in the suggestion step S7, the operator can adjust the casting speed of the casting operation according to the temperature of the molten steel in the sub-channel calculated in the calculation step S4. Among them, in the recommended step S7, the casting speed will decrease as the temperature of the molten steel in the separate steel channel increases, that is, the strategy of slow injection at high temperature and fast injection at low temperature is adopted.

Based on the above, the present invention utilizes relevant parameter information in the steelmaking process, including the characteristics of molten steel and ladles, existing materials and equipment characteristics, pre-scheduled operation time (production line scheduling time) and real-time measured data (actually measured data) is calculated, and through a conversion method that conforms to physical and statistical theories, the temperature changes of the molten steel in the separate steel tanks during the continuous casting stage can be estimated, which can assist production line production scheduling and control the temperature of the molten steel. Appropriate range, thereby improving the ability to adjust and control the continuous casting process parameters in real time to improve the quality of steel blanks and reduce production costs.

The features of several embodiments are summarized above, so that those skilled in the art can better understand the aspects of the present invention. Those skilled in the art should understand that they can easily use the present invention as a basis to design or modify other processes and structures to achieve the same goals and/or achieve the same advantages as the embodiments introduced here. . Those skilled in the art should also understand that these equivalent structures do not deviate from the spirit and scope of the present invention, and they can make various changes, substitutions and changes without departing from the spirit and scope of the present invention.

C1: Curve C2: Comparison chart S1: Preparation steps S2: Scheduling steps S3: Parameter acquisition steps S4: Operation steps S5: Output display steps S6: Early warning steps S7: Recommended steps

The aspect of the present invention can be better understood from the following detailed description combined with the accompanying drawings. It should be noted that, in accordance with standard industry practice, features are not drawn to scale. In fact, the dimensions of each feature may be arbitrarily increased or decreased for clarity of discussion. [Fig. 1] is a flow chart of a method for predicting the temperature of molten steel in a separate steel tank according to an embodiment of the present invention. [Fig. 2] Fig. 2 is an illustrative relational diagram of a conversion relational expression of a stored heat amount of a ladle according to an embodiment of the present invention. [Fig. 3] is a comparison diagram of predicted temperature and measured temperature according to an embodiment of the present invention. [Fig. 4] is a flow chart of a method for predicting the temperature of molten steel in a separate steel tank according to an embodiment of the present invention.

S1: Preparation steps

S2: Scheduling steps

S3: Parameter acquisition steps

S4: Operation steps

Claims (10)

A method for predicting the temperature of molten steel in separate steel tanks, including: Provide a ladle and a sub-trough, wherein the ladle is used to contain a molten steel for a refining operation, and the sub-trough is used to perform a casting operation after the refining operation to convert the molten steel from The ladle is poured into the sub-steel tank and then poured into the casting mold; A scheduling step to obtain a refining completion time point when the refining operation is completed and a current time point when the casting operation is performed; A parameter obtaining step obtains the following plural parameters: Obtain the temperature of the molten steel in the ladle at the refining completion time point; Obtain a first stored heat amount of the steel ladle at the current time point and a second stored heat amount of the steel ladle at the refining completion time point; Obtain a first temperature drop rate caused by the top slag surface of the molten steel in the steel drum and a second temperature drop rate caused by the outer shell of the steel drum; and Obtain the temperature drop that occurs when the molten steel is poured from the ladle into the sub-tank; and An operation step, performing operations based on the parameters to predict the temperature of the molten steel in one section of the steel channel in the section of the steel tank at the current time point; The scheduling step, the parameter obtaining step and the computing step are executed by a computer. As described in claim 1, the method for predicting the temperature of molten steel in a separate steel tank, wherein the calculation formula used in this operation step is: Where T _TD is the temperature of the molten steel in the sub-channel, T _Re is the temperature of the molten steel in the ladle at the time when the refining is completed, HeatLD _cc is the first stored heat, and HeatLD _Re is the second stored heat. , M _LD is the weight of the molten steel in the ladle at the refining completion time point, c is the specific heat value of the molten steel, Δt is the time difference between the refining completion time point and the current time point, R _shell is the second temperature drop rate, R _slag is the first temperature drop rate, and ΔT _LD-TD is the temperature drop that occurs when molten steel is poured from the ladle into the sub-steel tank. The method for predicting the temperature of molten steel in a separate steel tank as described in claim 1, wherein the first stored heat and the second stored heat will decrease as the number of times the steel ladle is used increases, and the first The stored heat and the second stored heat will increase as the weight of the shell of the steel drum and the refractory material in the drum increases. The method for predicting the temperature of the molten steel in the sub-trough as described in claim 1, wherein the second temperature drop rate will increase as the outer shell temperature of the steel drum increases, and the outer shell temperature of the steel drum will Increases as the ladle is used more often. The method for predicting the temperature of molten steel in a separate steel tank as described in claim 1, wherein the first temperature drop rate increases as the temperature of the top slag surface of the molten steel in the ladle increases. The method for predicting the temperature of molten steel in a separate steel tank as described in claim 1, wherein the first temperature drop rate when the top of the steel drum is not covered is greater than when the top of the steel drum is covered. The first temperature drop rate. The method for predicting the temperature of molten steel in a separate steel tank as described in claim 1, wherein the temperature drop of the steel ladle receiving the molten steel for the first time is greater than the temperature drop of the steel ladle not containing the molten steel for the first time. The temperature drops. The method for predicting the temperature of molten steel in the sub-tank as described in claim 1 further includes: An output display step displays the molten steel temperature of the sub-channel on a display screen of the computer; and An early warning step is to compare the temperature of the molten steel in the sub-channel with a set temperature, so as to issue an alarm when the temperature of the molten steel in the sub-channel is lower than the set temperature, wherein the pre-warning step is executed by the computer. The method for predicting the temperature of molten steel in a separate steel tank as described in claim 8, wherein the set temperature is a solidification temperature of the molten steel plus a buffer temperature, wherein the buffer temperature is associated with the steel type of the molten steel . The method for predicting the temperature of molten steel in the sub-tank as described in claim 1 further includes: A suggested step to adjust a casting speed of the casting operation according to the temperature of the molten steel in the sub-channel, wherein in the suggested step, the casting speed will decrease as the temperature of the molten steel in the sub-channel increases, wherein the suggestion The steps are performed by the computer.

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