Method for increasing charging temperature of casting blank

Abstract

The invention provides a method for increasing the in-furnace temperature of a casting blank, which relates to the technical field of steel smelting, and comprises the following steps: cutting the casting blank by a flame cutting machine, then enabling the casting blank to reach a blank discharge roller way, turning up the casting blank to a blank pushing sliding strip by a tilting gear, then conveying the casting blank on the blank pushing sliding strip to rolled steel by a blank moving vehicle, and setting the blank pushing mode of the blank moving vehicle to be three pieces / group; through an automatic program, the casting blank flow number is pre-judged in advance, and precise positioning of the blank moving vehicle is achieved; according to the casting blank temperature data of the withdrawal and straightening machine and the tilting gear of the casting machine, the water amount is reduced, and it is ensured that the temperature of the casting blank in front of the withdrawal and straightening machine is within the technological requirement standard range of 900-1100 DEG C; according to the method, the gas consumption and the power consumption of a steel rolling production line are effectively reduced by improving the furnace entering temperature index of the casting blank, and the furnace entering temperature of the casting blank is improved, the gas consumption of a heating furnace is saved, the energy is saved and the cost is reduced mainly by optimizing a continuous casting production process, transforming equipment, applying an automation technology and optimizing an operation mode.

Description

Technical Field

[0001] The present invention relates to the technical field of steel smelting, and in particular to a method for increasing the temperature of a casting billet entering a furnace. Background Art

[0002] In the steel industry, steel rolling fuel consumption accounts for more than 70% of the total energy consumption, and the fuel consumption is mainly generated in the heating process of the heating furnace. Therefore, energy saving in the heating furnace is crucial to energy saving in the entire rolling process. As the raw material for steel rolling, the higher the surface temperature of the continuous casting billet, the lower the fuel consumption cost of the heating furnace. At present, the billets between the steelmaking plant and the rolling mill are generally transported by rollers, cross-cars or cars. Among them, the billets are mainly transported by economical and efficient roller transportation. This method can utilize the physical heat energy of the continuous casting billet itself for rolling, which not only reduces fuel consumption and pollutant emissions, but also saves the cost of heating furnace maintenance. However, the surface temperature of the billet needs to be further increased. The roller transportation speed, distance, process downtime, equipment power, etc. will all affect the increase in the billet surface temperature.

[0003] In the continuous casting production of steelmaking, hot billets are preferentially arranged on the conveying rollers. When a group of billets is full on the conveying rollers, the conveying rollers are started and sent to the steel rolling mill, and then the billets are sent to the heating furnace by the chain elevator. This round trip realizes continuous conveying of billets. When the production rhythm of the steel rolling mill is adjusted or production is abnormal, the excess billets left over from the continuous casting of steelmaking are manually arranged to be taken off the line and stored in the furnace. However, during the transportation of the billets, the temperature loss during the casting process is large, which increases the gas consumption of the heating furnace. Therefore, the present invention proposes a method for increasing the temperature of the billets entering the furnace to solve the problems existing in the prior art. Summary of the Invention

[0004] In view of the above problems, the present invention proposes a method for increasing the temperature of the billet entering the furnace, which increases the temperature of the billet entering the furnace, saves gas consumption in the heating furnace, saves energy, and reduces costs.

[0005] To achieve the purpose of the present invention, the present invention is implemented through the following technical solutions: A method for increasing the temperature of the casting billet entering the furnace comprises the following steps:

[0006] S1: The ingot is cut by the hot cutting machine and then reaches the billet discharge roller. It is flipped by the steel turning machine onto the billet pusher. The billet pusher is then sent to the rolling mill by the billet transfer car. The billet transfer car is set to push 3 billets per group.

[0007] S2: Through automated procedures, the billet flow can be predicted in advance and the billet transfer car can be accurately positioned;

[0008] S3: According to the temperature data of the billet at the casting machine, straightening machine and steel turning machine, reduce the water volume to ensure that the billet temperature before the straightening machine is within the process requirement standard range of 900-1100℃;

[0009] S4: At the same casting speed, compare the operating temperatures of various mold slags and select the optimal mold slag;

[0010] S5: Assign a number to each ingot according to the number of continuous casting furnaces, flow times, and number of ingots in the furnace to ensure the uniqueness of the ingot and the authenticity of the ingot temperature measurement in both steelmaking and rolling;

[0011] S6: Under the premise of ensuring safe operation of the equipment, speed up the motors of the billet transfer car and hot delivery roller respectively;

[0012] S7: The transformation shortens the distance between steel rolling mills and reduces the number of billets stored in the process.

[0013] A further improvement is that: S2 includes the following steps:

[0014] S21: Positioning judgment of the billet transfer vehicle;

[0015] S22: According to the current billet pushing method of the billet transfer car, the existing billet transfer car is optimized to push three casting billets.

[0016] A further improvement is that: said S21 includes the following steps:

[0017] Add an incremental encoder to the transmission shaft of the transfer vehicle, and calculate the position of the transfer vehicle based on the circumference of the gear tooth tip and the number of times the encoder sends a signal;

[0018] The blank transfer vehicle is positioned at zero when it is in the waiting position. When the blank transfer vehicle starts to move forward, the encoder starts to increase the count and sets the corresponding values to 1, 2, 3, 4, and 5 positions to enable the blank transfer vehicle to stop at the flow position to be set.

[0019] A further improvement is that: said S22 includes the following steps:

[0020] According to the signal of the fire cutting machine, the turning of the blank can be predicted in advance;

[0021] Combined with the heat detection signals at the steel turning machines of each flow, the predicted signals are reconfirmed to achieve accurate positioning of the billet transfer car at each flow position.

[0022] Further improvements are as follows: in the above S3, the continuous casting billet is a process in which molten steel changes from liquid to solid, and the molten steel is cooled by water to become a cast billet. Under the premise of meeting the safety, production and quality stability of continuous casting, the water amount is further reduced according to the billet temperature data at the casting machine straightening machine and the steel turning machine to ensure that the billet temperature before the straightening machine is within the process requirement standard range of 900-1100°C, which can increase the lowest billet temperature by 5°C and the highest billet temperature by 25°C.

[0023] A further improvement is that in S4, the influence of various mold slags on the temperature of the ingot is tracked, and at the same casting speed of 4.0 m / min, the temperatures of various mold slags are compared to select the optimal mold slag.

[0024] A further improvement is that: said S5 comprises the following steps:

[0025] In order to unify steel rolling signals, the application of virtual numbering of ingots is promoted;

[0026] According to the number of continuous casting furnaces, streams, and the number of branches in the furnace, each ingot is assigned a number to ensure the uniqueness of the ingot and the authenticity of the ingot temperature measurement in both steelmaking and rolling.

[0027] According to the needs of steel rolling, the steel rolling heat detection signal is determined after the billet transfer car is turned on through the judgment of automated logic;

[0028] When there is no heat detection signal on the hot delivery roller in the steel rolling section, it means that there is no billet at the roller, and the steel rolling needs to feed the billet, then the billet transfer car stops at the hot delivery position and performs the billet feeding operation;

[0029] When the hot delivery roller of the steel rolling mill has a heat detection signal, it means that there is a billet on the roller table, and the billet is moved to the cooling bed.

[0030] A further improvement is that: S6 includes the following steps:

[0031] In order to increase the temperature of the furnace, based on the idea of "trading space for time and speed for time", the current steelmaking billets are pushed to the first section of the hot delivery roller by the billet transfer car, and then driven by the motor to the first and second sections of the hot delivery roller to the rolling mill billet rack, and then the lifting chain lifts the billets to the roller table before the steel rolling furnace;

[0032] Under the premise of ensuring the safe operation of the equipment, the speed of the motors of the billet transfer car and the hot delivery roller were increased respectively. The frequency of the billet transfer car motor was increased from 30hz to 40hz, and the frequency of the second section of the hot delivery roller was increased from 8hz to 10hz.

[0033] A further improvement is that in said S7, the stroke of the retracting oil cylinder at the rolling mill lifting chain is increased, and the number of billets stored on the collecting stand is set to 14-16.

[0034] The beneficial effects of the present invention are:

[0035] 1. The present invention effectively reduces the gas and electricity consumption of the steel rolling production line by improving the temperature index of the ingot entering the furnace. It mainly improves the ingot entering the furnace temperature, saves the gas consumption of the heating furnace, saves energy and reduces costs by optimizing the continuous casting production process, equipment transformation, application of automation technology and operation mode.

[0036] 2. The present invention optimizes the operation mode of the billet transfer car, reduces the temperature drop of the billet during the waiting process, optimizes the continuous casting cooling system, reduces the amount of cooling water for the billet and reduces the temperature loss of the billet surface while ensuring the quality of the billet. Through the combination of information and automation technology, the demand status of the steel rolling mill for the billet is obtained. The steelmaking mill arranges the delivery of the billet or arranges the billet to be taken off the line and stacked according to the demand status. By shortening the distance between steel rolling and steelmaking, the billet can reach the steel rolling mill at the fastest speed; under the premise of the equipment safety factor, the equipment operation speed is improved, thereby realizing the improvement of the billet operation rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Flowchart of the present invention. DETAILED DESCRIPTION

[0038] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the examples. The examples are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0039] Example 1

[0040] according to Figure 1 As shown, this embodiment proposes a method for increasing the temperature of the casting billet entering the furnace, comprising the following steps:

[0041] S1: The ingot is cut by the hot cutting machine and then reaches the billet discharge roller. It is flipped by the steel turning machine onto the billet pusher. The billet pusher is then sent to the rolling mill by the billet transfer car. The billet transfer car is set to push 3 billets per group.

[0042] S2: Through automated procedures, the billet flow can be predicted in advance and the billet transfer car can be accurately positioned;

[0043] S3: According to the temperature data of the billet at the casting machine, straightening machine and steel turning machine, reduce the water volume to ensure that the billet temperature before the straightening machine is within the process requirement standard range of 900-1100℃;

[0044] S4: At the same casting speed, compare the operating temperatures of various mold slags and select the optimal mold slag;

[0045] S5: Assign a number to each ingot according to the number of continuous casting furnaces, flow times, and number of ingots in the furnace to ensure the uniqueness of the ingot and the authenticity of the ingot temperature measurement in both steelmaking and rolling;

[0046] S6: Under the premise of ensuring the safe operation of the equipment, speed up the motors of the billet transfer car and the hot delivery roller respectively;

[0047] S7: The transformation shortens the distance between steel rolling mills and reduces the number of billets stored in the process.

[0048] The present invention prevents the problem of excessive temperature loss caused by stagnation of steel billets on the conveyor roller, effectively increases the temperature of the billets entering the furnace, and reduces the gas consumption of the heating furnace of the steel rolling mill. The method first optimizes the operation mode of the billet transfer car to reduce the temperature drop of the billets during the waiting process. Second, it optimizes the continuous casting cooling system to reduce the amount of cooling water for the billets and reduce the temperature loss on the surface of the billets while ensuring the quality of the billets. Third, through the combination of information and automation technology, the demand status of the steel rolling mill for billets can be obtained. The steelmaking plant arranges the delivery of billets or arranges the billets to be taken off the line and stacked according to the demand status; fourth, by shortening the distance between steel rolling and steelmaking, the billets can reach the steel rolling mill at the fastest speed; fifth, under the premise of the equipment safety factor, the equipment operation speed is increased, thereby realizing the improvement of the billet operation rate.

[0049] Example 2

[0050] according to Figure 1 As shown, this embodiment proposes a method for increasing the temperature of the casting billet entering the furnace, comprising the following steps:

[0051] After being cut by the hot cutting machine, the ingot reaches the billet discharge roller, and then is turned over by the steel turning machine to the billet pusher slide. The billet pusher then sends the billet on the billet pusher slide to the rolling mill. The number of billets pushed is mainly determined by the production rhythm and the operating habits of the position. Normal operation mainly pushes 4 billets / group, which causes the billets to be kept waiting. Heat is lost during the process, and the billets cannot be sent to the rolling mill in time. Therefore, the billet pushing method of the billet transfer car is optimized. The current billet pushing method of 4 billets / group is changed to 3 billets / group. The specific data is shown in Table 1:

[0052]

[0053] Table 1: Comparison of test data of different methods

[0054] The above data shows that, at the same casting speed, the three-bill operation method increases the furnace temperature by approximately 36°C compared to the four-bill operation method, while also shortening the time from the steel transfer machine to furnace entry by 0.71 min. This demonstrates that this billet pushing method reduces the time the billet transfer car spends waiting for billet assembly, shortens the time between steelmaking and rolling, and significantly increases the billet temperature.

[0055] Through the automated program, the flow of the billet can be predicted in advance, and ultimately the precise positioning of the billet transfer car can be achieved.

[0056] Positioning judgment of the billet transfer car:

[0057] (1) Add an incremental encoder to the transmission shaft of the transfer vehicle, and calculate the position of the transfer vehicle based on the circumference of the gear tooth top circle and the number of times the encoder sends a signal.

[0058] (2) The blank transfer car is positioned at zero when it is in the waiting position. When the blank transfer car starts to move forward, the encoder starts to increase the count and sets the corresponding values to 1, 2, 3, 4, and 5 to enable the blank transfer car to stop at the flow position to be set.

[0059] According to the current billet pushing method of the billet transfer car, the existing billet transfer car pushing three billets is optimized. The billet turning can be predicted in advance according to the signal of the fire cutting machine. At the same time, combined with the heat detection signal at the steel turning machine of each flow, the predicted signal is confirmed for the second time, so that the billet transfer car can be accurately positioned at the position of each flow, avoiding the billet transfer car returning to the initial position after each billet pushing is completed, and the billet transfer car operation time can be shortened by about 10S.

[0060] Continuous casting is the process of molten steel changing from liquid to solid, which is mainly done by cooling the molten steel with water to form a billet. Under the premise of meeting the requirements of continuous casting safety, production and stable quality, the amount of water can be further reduced according to the billet temperature data at the casting machine, straightening machine and steel turning machine to ensure that the billet temperature before the straightening machine is within the process requirement standard range of 900-1100℃. The billet temperature can be increased by 5℃ for the lowest flow and 25℃ for the highest flow (Table 3).

[0061]

[0062] Table 2: Temperature measurement data of the slab surface before improvement

[0063]

[0064] Table 3: Surface temperature measurement data of billet after improvement

[0065] Protective slag is called the "industrial MSG" of continuous casting and plays a decisive role in the production and quality of continuous casting. It is dissolved into slag liquid by the temperature of molten steel and flows into the space between the copper tube of the crystallizer and the shell of the ingot, forming a slag film to play a role in lubrication and heat transfer. However, due to the different raw materials and processes used by each manufacturer, the slag film on the surface of the ingot does not fall off or falls off partially, thereby affecting the cooling of the ingot surface by water. Therefore, by tracking the influence of protective slag on the ingot temperature, at the same casting speed of 4.0m / min, the use temperature of Xibao and Tongyu protective slags was compared. The average surface temperature of the ingot made by Tongyu protective slag was 26℃ higher than that of Xibao protective slag (Table 4).

[0066] Flow Steel turning machine temperature (℃) Temperature of hot delivery roller (℃) Rolling furnace temperature (℃) Remark S1 918 909 850 Xibao protective slag S2 882 897 854 Xibao protective slag S1 902 945 870 Tongyu protective slag S2 906 945 886 Tongyu protective slag

[0067] Table 4: Comparison of casting temperatures of different mold slags

[0068] To unify steel rolling signals, the application of virtual numbering for ingots has been promoted. The virtual numbering is mainly based on the number of continuous casting furnaces, the number of flows, and the number of ingots in the furnace. Each ingot is assigned a number, ensuring the uniqueness of the ingot and the authenticity of the ingot temperature measurement during steelmaking and rolling. At the same time, according to the needs of steel rolling, it can be increased through the judgment of automated logic. For example, after the ingot transfer car is turned on, the steel rolling heat detection signal is determined. When there is no heat detection signal on the hot delivery roller of the steel rolling section, it means that there is no ingot at the roller. The steel rolling needs to feed the ingot. The ingot transfer car stops at the hot delivery position and performs the ingot feeding operation. When there is a heat detection signal on the hot delivery roller of the steel rolling section, it means that there is a ingot at the roller, and the ingot is transferred to the cooling bed.

[0069] The equipment speed is increased, and the time for the billets to enter the furnace is shortened. In order to increase the temperature entering the furnace, based on the idea of "trading space for time and speed for time", the current steelmaking billets are pushed to the hot delivery roller (first section) by the billet transfer car, and then driven by the motor to send the hot delivery roller (first section) and the hot delivery roller (second section) to the rolling mill billet rack, and then the billet is lifted to the roller before the rolling mill enters the furnace by the lifting chain. Under the premise of ensuring the safe operation of the equipment, the billet transfer car and the hot delivery roller motor are speeded up respectively. The billet transfer car motor frequency is increased from 30hz to 40hz, and the hot delivery roller (second section) frequency is increased from 8hz to 10hz. The combined improvements of the two items can shorten the billet operation time by more than 15s.

[0070] The effective connection between the distance between steelmaking and steel rolling and the demand for ensuring the rolling speed of steel rolling is particularly important. Therefore, the distance between steel rolling and the number of billets stored in the process can be shortened through transformation, thereby reducing the invisible waste of billet temperature during the waiting process. Therefore, the stroke of the contraction cylinder at the steel rolling lifting chain is increased, and the original collection rack billet storage capacity is increased to 20. After the equipment and technical transformation, the steel rolling billet collection rack position reduces the storage capacity of 15 billets, ensuring the storage capacity of one group of billets, and effectively reducing unnecessary temperature loss during the waiting process of billets.

[0071] This method of increasing the temperature of the ingot entering the furnace effectively reduces the gas consumption and electricity consumption of the steel rolling production line by improving the ingot entering the furnace temperature index. It mainly increases the ingot entering the furnace temperature, saves the gas consumption of the heating furnace, saves energy, and reduces costs by optimizing the continuous casting production process, equipment transformation, application of automation technology, and optimization of operation methods. Specific indicators are shown in Table 5.

[0072]

[0073]

[0074] Table 5: Furnace temperature and gas consumption completion status

[0075] The present invention optimizes the operation mode of the billet transfer car, reduces the temperature drop of the billet during the waiting process, optimizes the continuous casting cooling system, reduces the amount of cooling water for the billet and reduces the temperature loss of the billet surface under the premise of ensuring the quality of the billet, and realizes the acquisition of the demand status of the steel rolling mill for the billet through the combination of information and automation technology. The steelmaking mill arranges the shipment of the billet or arranges the billet to be taken off the line and stacked according to the demand status. By shortening the distance between steel rolling and steelmaking, the billet can reach the steel rolling mill at the fastest speed; under the premise of the equipment safety factor, the equipment operation speed is improved, thereby realizing the improvement of the billet operation rate.

[0076] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for increasing the temperature of a casting billet entering a furnace, characterized in that: The following steps are involved: S1: The ingot is cut by the hot cutting machine and then reaches the billet discharge roller. It is flipped by the steel turning machine onto the billet pusher. The billet pusher is then sent to the rolling mill by the billet transfer car. The billet transfer car is set to push 3 billets per group. S2: Through automated procedures, the billet flow can be predicted in advance and the billet transfer car can be accurately positioned; S3: According to the temperature data of the billet at the casting machine, straightening machine and steel turning machine, reduce the water volume to ensure that the billet temperature before the straightening machine is within the process requirement standard range of 900-1100℃; S4: At the same casting speed, compare the operating temperatures of various mold slags and select the optimal mold slag; S5: Assign a number to each ingot according to the number of continuous casting furnaces, flow times, and number of ingots in the furnace to ensure the uniqueness of the ingot and the authenticity of the ingot temperature measurement in both steelmaking and rolling; S6: Under the premise of ensuring safe operation of the equipment, speed up the motors of the billet transfer car and hot delivery roller respectively; S7: The transformation shortens the distance between steel rolling mills and reduces the number of billets stored in the process.

2. The method for increasing the temperature of the casting billet entering the furnace according to claim 1, wherein: The S2 comprises the following steps: S21: Positioning judgment of the billet transfer vehicle; S22: According to the current billet pushing method of the billet transfer car, the existing billet transfer car is optimized to push three casting billets.

3. The method for increasing the temperature of the casting billet entering the furnace according to claim 2, wherein: The S21 includes the following steps: Add an incremental encoder to the transmission shaft of the transfer vehicle, and calculate the position of the transfer vehicle based on the circumference of the gear tooth tip and the number of times the encoder sends a signal; The blank transfer vehicle is positioned at zero when it is in the waiting position. When the blank transfer vehicle starts to move forward, the encoder starts to increase the count and sets the corresponding values to 1, 2, 3, 4, and 5 positions to enable the blank transfer vehicle to stop at the flow position to be set.

4. The method for increasing the temperature of the casting billet entering the furnace according to claim 3, wherein: The S22 includes the following steps: According to the signal of the fire cutting machine, the turning of the blank can be predicted in advance; Combined with the heat detection signals at the steel turning machines of each flow, the predicted signals are reconfirmed to achieve accurate positioning of the billet transfer car at each flow position.

5. The method for increasing the temperature of the casting billet entering the furnace according to claim 1, wherein: In the above S3, the continuous casting process is a process in which molten steel changes from liquid to solid. The molten steel is cooled by water to form a cast billet. Under the premise of meeting the requirements of continuous casting safety, production and stable quality, the water amount is further reduced according to the billet temperature data at the casting machine straightening machine and the steel turning machine to ensure that the billet temperature before the straightening machine is within the process requirement standard range of 900-1100°C. The lowest billet temperature can be increased by 5°C and the highest billet temperature can be increased by 25°C.

6. The method for increasing the temperature of the casting billet entering the furnace according to claim 1, wherein: In the above-mentioned S4, the influence of various mold slags on the temperature of the ingot is tracked, and at the same casting speed of 4.0 m / min, the temperatures of various mold slags are compared to select the optimal mold slag.

7. The method for increasing the temperature of the casting billet entering the furnace according to claim 1, wherein: The S5 comprises the following steps: In order to unify steel rolling signals, the application of virtual numbering of ingots is promoted; According to the number of continuous casting furnaces, streams, and the number of branches in the furnace, each ingot is assigned a number to ensure the uniqueness of the ingot and the authenticity of the ingot temperature measurement in both steelmaking and rolling. According to the needs of steel rolling, the steel rolling heat detection signal is determined after the billet transfer car is turned on through the judgment of automated logic; When there is no heat detection signal on the hot delivery roller in the steel rolling section, it means that there is no billet at the roller, and the steel rolling needs to feed the billet, then the billet transfer car stops at the hot delivery position and performs the billet feeding operation; When the hot delivery roller of the steel rolling mill has a heat detection signal, it means that there is a billet on the roller table, and the billet is moved to the cooling bed.

8. The method for increasing the temperature of the casting billet entering the furnace according to claim 1, wherein: The S6 comprises the following steps: To increase the temperature entering the furnace, based on the concept of "trading space for time and speed for time", the current steelmaking ingot is pushed to the first section of the hot delivery roller by the ingot transfer car, and then driven by the motor to the first and second sections of the hot delivery roller to the rolling mill ingot rack, and then the lifting chain lifts the ingot to the roller before the rolling mill into the furnace; Under the premise of ensuring the safe operation of the equipment, the speed of the motors of the billet transfer car and the hot delivery roller were increased respectively. The frequency of the billet transfer car motor was increased from 30hz to 40hz, and the frequency of the second section of the hot delivery roller was increased from 8hz to 10hz.

9. The method for increasing the temperature of the casting billet entering the furnace according to claim 1, wherein: In the above-mentioned S7, the stroke of the contraction oil cylinder at the rolling mill lifting chain is increased, and the number of billets stored on the collecting stand is set to 14-16.

Images