A constant speed device and method for improving the quick change process of a continuous casting submerged nozzle

Abstract

The application discloses a device and method for improving constant rate during quick change process of continuous casting submerged nozzle, which comprises a tundish, a containing cavity is formed on the tundish, a flow guide hole is also formed on the tundish, the flow guide hole is communicated with the containing cavity; a submerged nozzle, the first end of the submerged nozzle is communicated with the containing cavity through the flow guide hole; a stopper, an air outlet pipe is arranged in the stopper; a quick change nozzle, the quick change nozzle is located on one side of the submerged nozzle; an upper nozzle, the upper nozzle is installed on the tundish, the output end of the upper nozzle is located on the inner side wall of the flow guide hole, and the input end of the upper nozzle is outwardly extended; a protective gas channel, the input end of the protective gas channel is communicated with an argon source, the input end of the protective gas channel is respectively communicated with the air outlet pipe and the input end of the upper nozzle; and an adjusting unit, the adjusting unit is installed on the protective gas channel. The application keeps constant rate during quick change, and ensures that the replacement of the nozzle is completed within the production cycle of a single slab.

Description

Technical Field

[0001] This invention relates to the field of continuous casting production technology, and in particular to a device and method for improving the constant rate of the quick change process of the submersible nozzle in continuous casting. Background Technology

[0002] During continuous casting, changes in the flow rate of molten steel within the mold cause variations in the flow field. These changes significantly impact the stability of the molten steel surface and the solidification process of the billet shell, leading to a decline in both the surface and internal quality of the continuously cast slab. Therefore, maintaining a stable flow rate is crucial for improving slab quality during continuous casting, which necessitates a constant pouring rate: a constant pouring rate is a key indicator for ensuring stable slab quality. To improve continuous casting performance, the submersible nozzle in the mold needs to be quickly replaced after a certain pouring time. To ensure safety during this replacement process, the pouring rate must be reduced, resulting in deterioration of slab quality during the speed adjustments before and after the replacement.

[0003] In the prior art, patent application number CN202311424386.4 discloses a protective casting device and method for continuous casting, including a box structure with an open top, a quick-change sprue device, and a protective gas supply device; an immersion sprue through hole is provided on the bottom plate of the box structure, and a first side opening is provided on the side wall of the box structure; a first push-pull plate and a second push-pull plate are respectively provided in two opposite directions of the first side opening; when the first push-pull plate and the second push-pull plate are pushed and pulled to the docking position, the first half hole and the second half hole dock to form a power element through hole; a second side opening corresponding to the position of the first side opening is provided on the side wall of the box structure, and a baffle is slidably provided at the second side opening.

[0004] The general definition of constant casting speed is: after excluding process factors (B / T billet), the compliance rate of slab casting speed fluctuation ≤ ±0.1 m / min. Many factors can affect slab non-constant speed. During continuous casting production, various process requirements, such as adjustments to the primary cooling water, quick changes to the submerged entry nozzle, width adjustment, crystallizer vibration parameter adjustments, malfunctions in upstream equipment causing rhythm delays, and malfunctions in downstream cutting equipment, necessitate speed reduction, leading to non-constant slab speed and thus affecting slab quality. Continuous casting requires constant casting speed. Under these conditions, during secondary cooling, the vibration parameters remain unchanged, the internal microstructure of the slab is stable, and the slab quality is also stable. Changes in casting speed during secondary cooling alter the vibration parameters, change the internal solidification microstructure of the slab, and consequently, affect the slab quality.

[0005] The quick-change operation of the submerged entry nozzle is a critical factor affecting the constant rolling speed of slabs. Under normal circumstances, the entire quick-change process takes about 5 minutes if all steps proceed smoothly. However, the existing quick-change method starts at the highest temperature of the furnace steel and directly reduces the speed without considering the slab length. If the reduction point is at the last three-quarters of a slab and the target drawing speed is above 1.3 m / min, the entire quick-change operation will span three slabs, resulting in non-constant speed across the three slabs. This severely affects the constant rolling speed index, impacts the hot rolling sealing rate, and further hinders the synchronous adjustment of the protective gas injection during the reduction process, leading to molten steel overflow. Therefore, it is necessary to improve this method to overcome these shortcomings. Summary of the Invention

[0006] The purpose of this invention is to provide a device and method for improving the constant speed of quick-change process in continuous casting submerged entry nozzles. It establishes a dedicated operation process screen for quick-change, avoids non-constant speed of slabs caused by manual confirmation of slab length deviation, reduces manual confirmation work, and ensures that quick-change is completed within the length of one slab. In addition, the automatic argon gas control system in quick-change mode automatically adjusts the argon gas input, which may cause molten steel to overflow from the mechanism's chute during nozzle switching due to excessive argon gas, thus creating a potential hazard for later casting.

[0007] The above-mentioned technical objective of this invention has been achieved by the following technical solutions:

[0008] A device for improving the constant rate of quick-change process in continuous casting submersible nozzles includes,

[0009] The intermediate tundish has a receiving cavity and a flow guide hole, which is connected to the receiving cavity.

[0010] The submersible nozzle has a first end that is connected to the receiving cavity through a guide hole, and a second end that extends outward from the tundish.

[0011] The stopper rod has a first end located inside the receiving cavity and facing the guide hole, and a second end of the stopper rod facing the outside of the receiving cavity. An air outlet pipe is provided inside the stopper rod, and the output end of the air outlet pipe faces the guide hole.

[0012] Quick-change sprue is installed on the tundish and is located on the side of the submersible sprue. The quick-change sprue is used to quickly replace the submersible sprue without stopping the machine for cooling.

[0013] The water inlet is installed on the intermediate tank. The output end of the water inlet is located on the inner wall of the guide hole, and the input end of the water inlet extends outward.

[0014] The protective gas channel has an input end connected to the argon gas source and an input end connected to the outlet pipe and the water inlet respectively. The protective gas flows into the inlet pipe and the water inlet respectively through the channel.

[0015] The regulating unit is installed on the protective gas passage and is used to regulate the opening and closing of the protective gas passage and the flow rate of the protective gas.

[0016] A further configuration of the present invention is as follows: the protective gas channel includes channel one and channel two; the input end of channel one is connected to the argon gas source of the stopper rod, and the output end of channel one is connected to the inlet pipe. Argon gas flows into the inlet pipe through channel one and then sprays out from the output end of the inlet pipe into the guide hole; the input end of channel two is connected to the argon gas source of the water inlet, and the output end of channel two is connected to the water inlet. Argon gas flows into the water inlet through channel two and then sprays out from the output end of the water inlet into the guide hole.

[0017] A further configuration of the present invention is as follows: the regulating unit includes regulating unit one and regulating unit two. Regulating unit one includes flow regulating valve one and flow meter one. Both flow regulating valve one and flow meter one are installed on channel one. Flow regulating valve one is used to regulate the flow rate of argon gas flowing into channel one, and flow meter one is used to obtain the real-time inflow of argon gas into the stopper rod.

[0018] The second regulating unit includes a second flow regulating valve and a second flow meter. Both the second flow regulating valve and the second flow meter are installed on the second channel. The second flow regulating valve is used to regulate the flow rate of argon gas flowing into the second channel, and the second flow meter is used to obtain the real-time inflow of argon gas at the water inlet.

[0019] A method for using a constant rate device to improve the quick change process of submerged entry nozzles in continuous casting includes the following steps:

[0020] A1: Pulling speed adjustment. When it is necessary to replace the nozzle, start the automatic adjustment mode to reduce the pulling speed until the pulling speed is at the first preset value. At this time, the argon gas input is at the highest value, and proceed to the next step.

[0021] A2: Argon gas regulation. When the pulling speed is at the first preset value, the argon gas regulation mode is activated. At this time, the pulling speed decreases at a constant speed, and the input argon gas to the stopper rod and the argon gas to the upper water inlet are reduced simultaneously. When the pulling speed reaches the second preset value, proceed to the next step.

[0022] A3: Replace the nozzle. When the pulling speed is at the second preset value, the input of argon gas to the stopper rod and the upper nozzle is at the lowest value and remains constant. At this time, replace the nozzle and the pulling speed will drop to the third preset value.

[0023] A4: After the nozzle replacement is completed, increase the casting speed of the continuous casting machine and increase the input argon gas volume. When the casting speed of the continuous casting machine reaches the first preset value and the argon gas input volume reaches the maximum value simultaneously, the quick replacement process ends.

[0024] The first preset value is 1.2 m / min, the second preset value is 0.6 m / min, and the third preset value is 0.4 m / min.

[0025] In summary, the present invention has the following beneficial effects:

[0026] 1. Improve production efficiency: By maintaining a constant rate for quick changeover, it can be ensured that the gate replacement is completed within the production cycle of a single slab, thereby reducing production downtime and improving overall production efficiency.

[0027] 2. Enhanced safety: By increasing the level of automation and avoiding human error, safety accidents such as molten steel spillage can be effectively prevented, thereby ensuring the safety of production personnel. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating the present invention.

[0029] Figure 2 This is a schematic diagram of the structure of the present invention.

[0030] Figure 3 This is a flowchart of the quick-change process of the present invention.

[0031] Figure 4 This is a schematic diagram of the quick-change principle of the present invention. Detailed Implementation

[0032] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to the figures and specific embodiments.

[0033] The reason for the large number of non-constant speed slabs during the quick change process is that the deceleration point is not accurately controlled at the beginning of the quick change, and the deceleration begins in the later stage of the slab before the quick change. Also, the slab length is not properly confirmed during the speed increase process after the quick change, resulting in non-constant speed between the two slabs before and after the quick change. To address this, the present invention proposes the following solution.

[0034] like Figure 1 and 2 As shown, the present invention proposes a device for improving the constant rate of the rapid changeover process in a continuous casting submersible nozzle, comprising:

[0035] The intermediate tundish has a receiving cavity and a flow guide hole, which is connected to the receiving cavity.

[0036] The submersible nozzle has a first end that is connected to the receiving cavity through a guide hole, and a second end that extends outward from the tundish.

[0037] The stopper rod has a first end located inside the receiving cavity and facing the guide hole, and a second end of the stopper rod facing the outside of the receiving cavity. An air outlet pipe is provided inside the stopper rod, and the output end of the air outlet pipe faces the guide hole.

[0038] Quick-change sprue is installed on the tundish and is located on the side of the submersible sprue. The quick-change sprue is used to quickly replace the submersible sprue without stopping the machine for cooling.

[0039] The water inlet is installed on the intermediate tank. The output end of the water inlet is located on the inner wall of the guide hole, and the input end of the water inlet extends outward.

[0040] The protective gas channel has an input end connected to the argon gas source and an input end connected to the outlet pipe and the water inlet respectively. The protective gas flows into the inlet pipe and the water inlet respectively through the channel.

[0041] The regulating unit is installed on the protective gas passage and is used to regulate the opening and closing of the protective gas passage and the flow rate of the protective gas.

[0042] The protective gas channel includes channel one and channel two. The input end of channel one is connected to the argon gas source of the stopper rod, and the output end of channel one is connected to the inlet pipe. Argon gas flows into the inlet pipe through channel one and then sprays out from the output end of the inlet pipe into the guide hole. The input end of channel two is connected to the argon gas source of the water inlet, and the output end of channel two is connected to the water inlet. Argon gas flows into the water inlet through channel two and then sprays out from the output end of the water inlet into the guide hole.

[0043] The regulating unit includes regulating unit one and regulating unit two. Regulating unit one includes a flow regulating valve one and a flow meter one. Both the flow regulating valve one and the flow meter one are installed on channel one. The flow regulating valve one is used to regulate the flow rate of argon gas flowing into channel one, and the flow meter one is used to obtain the real-time inflow of argon gas into the stopper rod. Regulating unit two includes a flow regulating valve two and a flow meter two. Both the flow regulating valve two and the flow meter two are installed on channel two. The flow regulating valve two is used to regulate the flow rate of argon gas flowing into channel two, and the flow meter two is used to obtain the real-time inflow of argon gas into the water inlet.

[0044] This device, through its quick-change nozzle design, enables rapid replacement of submersible nozzles without the need for shutdown cooling, thereby significantly improving the continuity and efficiency of continuous casting production. During the replacement process, precise control of the protective gas flow rate ensures the stability of the environment surrounding the submersible nozzle, avoiding production quality problems caused by the replacement. The precise adjustment of the protective gas flow rate by the regulating unit ensures the stability of the protective gas during the replacement process.

[0045] A method for using a constant rate device to improve the quick change process of submerged entry nozzles in continuous casting includes the following steps:

[0046] A1: Pulling speed adjustment. When it is necessary to replace the nozzle, start the automatic adjustment mode to reduce the pulling speed until the pulling speed is at the first preset value. At this time, the argon gas input is at the highest value, and proceed to the next step.

[0047] The automatic adjustment mode ensures a smooth reduction in pulling speed, avoiding the impact of sudden changes on production. By setting the first preset value, the degree of reduction in pulling speed can be precisely controlled, preparing for subsequent argon gas adjustment and nozzle replacement.

[0048] A2: Argon gas regulation. When the pulling speed is at the first preset value, the argon gas regulation mode is activated. At this time, the pulling speed decreases at a constant speed, and the input argon gas to the stopper rod and the argon gas to the upper water inlet are reduced simultaneously. When the pulling speed reaches the second preset value, proceed to the next step.

[0049] Synchronous adjustment of casting speed and argon gas input can ensure the stability and continuity of the production process. Reducing the argon gas input while lowering the casting speed can maintain the stability of molten steel.

[0050] A3: Replace the nozzle. When the pulling speed is at the second preset value, the input of argon gas to the stopper rod and the upper nozzle is at the lowest value and remains constant. At this time, replace the nozzle and the pulling speed will drop to the third preset value.

[0051] The nozzle replacement is carried out under the condition of minimum and constant argon input, and the nozzle replacement work is completed under the premise of ensuring production safety and efficiency.

[0052] A4: After the nozzle replacement is completed, increase the casting speed of the continuous casting machine and increase the input argon gas. When the casting speed of the continuous casting machine is increased to the first preset value and the input argon gas is simultaneously increased to the maximum value, the quick replacement process ends.

[0053] After the sprue replacement was completed, the production line was restored to normal operation by increasing the casting speed and the argon gas input.

[0054] like Figure 3 and 4As shown, when the ladle is opened for casting and the casting volume reaches less than 250 tons, the system will automatically activate the quick change screen to remind the operator to prepare for a quick change operation. When the quick change screen is yellow, it indicates that the current slab is still in the constant speed casting stage. At this time, the operator will reduce the casting speed by 0.1 m / min to reduce the subsequent casting speed. When the quick change screen turns blue, it indicates that the deceleration quick change operation can begin. When the quick change screen turns green, it indicates that there is no limit to the speed increase or decrease of the current slab during the quick change process. When the quick change operation is completed and the next slab is entered, the quick change screen will turn yellow again. At this time, the operator can increase the casting speed by 0.1 m / min to ensure that the next slab is still cast at a constant speed.

[0055] Example 1

[0056] In this embodiment, after the first 250 tons of billet are poured in the quick-change furnace, the central control operator activates the quick-change. Before the quick-change, the original target casting speed was 1.4 m / min, and the argon gas input at the inlet and stopper rod was 9 L each. The casting speed was reduced by 0.1 m / min. After the subsequent quick-change slabs appeared, the casting speed was reduced to the second preset value of 0.6 m / min. When the casting speed was less than the first preset value of 1.2 m / min, for every 0.1 m / min decrease in casting speed, flow control valve one was reduced by 1 L according to flow meter one, and flow control valve two was reduced by 1 L according to flow meter two, until the casting speed dropped to the second preset value of 0.6 m / min. At time n, the argon input at the water inlet and the stopper rod are automatically adjusted to 3L each. The water inlet is switched, and the speed is reduced to the third preset value of 0.4m / min. After the slag removal operation, the speed is increased. When the pulling speed is increased to the second preset value of 0.6m / min or higher, for every 0.1m / min increase in pulling speed, the flow regulating valve one is increased by 1L according to the flow meter one, and the flow regulating valve two is increased by 1L according to the flow meter two, until the pulling speed is increased to the first preset value of 1.2m / min. At this time, the argon input at the water inlet and the stopper rod is automatically adjusted to the maximum value of 9L. The automatic adjustment of argon ends, the quick change process ends, and the system switches back to manual adjustment mode.

[0057] Before and after adopting this technical solution, statistics on the constant speed of the quick-change billet of the continuous casting machine showed that, on average, there were 20 quick changes per month, which would produce about 48 non-constant speed billets. After implementation, the number of non-constant speed billets produced by quick changes was about 20, which effectively reduced the number of non-constant speed billets cleaned by the machine and improved the continuous casting yield.

[0058] Example 2

[0059] In this embodiment, after the first 250 tons of ladle casting in the quick-change furnace, the central control operator activates the quick-change screen. The target casting speed before the quick-change is 1.3 m / min, and the argon input at the inlet and stopper is 8L and 7L respectively. The casting speed is reduced by 0.1 m / min. After the subsequent quick-change slab appears, the casting speed is reduced to the second preset value of 0.6 m / min. When the casting speed is less than the first preset value of 1.2 m / min, for every 0.1 m / min decrease in casting speed, flow control valve one is reduced by 1L according to flow meter one, and flow control valve two is reduced by 1L according to flow meter two. When the casting speed drops to the second preset value of 0.6 m / min... The argon input at the inlet is automatically adjusted to 2L, and the argon input at the stopper rod is automatically adjusted to 1L. The inlet is switched, and the speed is reduced to the third preset value of 0.4m / min. After the slag removal operation, the speed is increased. When the pulling speed is increased to above 0.6m / min, for every 0.1m / min increase in pulling speed, the flow regulating valve one is increased by 1L according to the flow meter one, and the flow regulating valve two is increased by 1L according to the flow meter two, until the pulling speed is increased to the first preset value of 1.2m / min. The argon input at the inlet and the stopper rod is automatically adjusted to the initial values ​​of 8L and 7L respectively. The automatic adjustment of argon is completed, the quick change process is completed, and the system is switched back to manual adjustment mode.

[0060] Before and after adopting this technical solution, statistics on the constant speed of the quick-change billet of the continuous casting machine showed that, on average, there were 25 quick changes per month, which would produce about 60 non-constant speed billets. After implementation, the number of non-constant speed billets produced by quick changes was about 25, which effectively reduced the number of non-constant speed billets cleaned by the machine and improved the continuous casting yield.

[0061] The usage process and principle of this invention are as follows: When it is necessary to replace the nozzle, the system first reduces the casting speed through an automatic adjustment mode to ensure a smooth transition in the production process. The degree of speed reduction is precisely controlled by setting a first preset value, preparing for subsequent argon gas adjustment and nozzle replacement. Simultaneously with the speed reduction, the system reduces the input argon gas to the stopper rod and the upper nozzle to maintain the stability of the molten steel. When the casting speed drops to a second preset value, the system enters the nozzle replacement stage. At this point, the argon gas input has reached its minimum and constant state. After the nozzle replacement is completed, the system restores normal operation of the production line by increasing the casting speed and the argon gas input. Throughout the process, the system monitors changes in casting speed and argon gas input in real time through an intelligent monitoring and feedback mechanism, and automatically adjusts as needed. This intelligent monitoring and feedback mechanism ensures the stability and continuity of the production process, improving production efficiency and quality.

[0062] In summary, by precisely controlling the changes in casting speed and argon gas input, rapid replacement of the submerged entry nozzle in continuous casting was achieved, while maintaining the stability and continuity of the production process, thereby improving production efficiency.

[0063] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. These terms are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connect" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. In this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0064] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A device for improving the constant rate of rapid changeover in a continuous casting submersible nozzle process, characterized in that, include, The intermediate tundish has a receiving cavity and a flow guide hole, which is connected to the receiving cavity. The submersible nozzle has a first end that is connected to the receiving cavity through a guide hole, and a second end that extends outward from the tundish. The stopper rod has a first end located inside the receiving cavity and facing the guide hole, and a second end of the stopper rod facing the outside of the receiving cavity. An air outlet pipe is provided inside the stopper rod, and the output end of the air outlet pipe faces the guide hole. Quick-change sprue is installed on the tundish and is located on the side of the submersible sprue. The quick-change sprue is used to quickly replace the submersible sprue without stopping the machine for cooling. The water inlet is installed on the intermediate tank. The output end of the water inlet is located on the inner wall of the guide hole, and the input end of the water inlet extends outward. The protective gas channel has an input end connected to the argon gas source and an input end connected to the outlet pipe and the water inlet respectively. The protective gas flows into the inlet pipe and the water inlet respectively through the channel. The regulating unit is installed on the protective gas passage and is used to regulate the opening and closing of the protective gas passage and the flow rate of the protective gas.

2. The device for improving the constant rate of rapid changeover process in continuous casting submersible nozzles according to claim 1, characterized in that, The protective gas channel includes channel one and channel two. The input end of channel one is connected to the argon gas source of the stopper rod, and the output end of channel one is connected to the inlet pipe. Argon gas flows into the inlet pipe through channel one and then sprays out from the output end of the inlet pipe into the guide hole. The input end of channel two is connected to the argon gas source of the water inlet, and the output end of channel two is connected to the water inlet. Argon gas flows into the water inlet through channel two and then sprays out from the output end of the water inlet into the guide hole.

3. The device for improving the constant rate of rapid changeover process in continuous casting submersible nozzles according to claim 1, characterized in that, The adjustment unit includes adjustment unit one and adjustment unit two. The regulating unit includes a flow regulating valve and a flow meter. Both the flow regulating valve and the flow meter are installed on the channel. The flow regulating valve is used to regulate the flow rate of argon gas flowing into the channel, and the flow meter is used to obtain the real-time inflow of argon gas into the stopper rod. The second regulating unit includes a second flow regulating valve and a second flow meter. Both the second flow regulating valve and the second flow meter are installed on the second channel. The second flow regulating valve is used to regulate the flow rate of argon gas flowing into the second channel, and the second flow meter is used to obtain the real-time inflow of argon gas at the water inlet.

4. A method for using a constant rate device to improve the quick-change process of submerged entry nozzles in continuous casting, comprising the following steps: A1: Pulling speed adjustment. When it is necessary to replace the nozzle, start the automatic adjustment mode to reduce the pulling speed until the pulling speed is at the first preset value. At this time, the argon gas input is at the highest value, and proceed to the next step. A2: Argon gas regulation. When the pulling speed is at the first preset value, the argon gas regulation mode is activated. At this time, the pulling speed decreases at a constant speed, and the input argon gas to the stopper rod and the argon gas to the upper water inlet are reduced simultaneously. When the pulling speed reaches the second preset value, proceed to the next step. A3: Replace the nozzle. When the pulling speed is at the second preset value, the input of argon gas to the stopper rod and the upper nozzle is at the lowest value and remains constant. At this time, replace the nozzle and the pulling speed will drop to the third preset value. A4: After the nozzle replacement is completed, increase the casting speed of the continuous casting machine and increase the input argon gas volume. When the casting speed of the continuous casting machine reaches the first preset value and the argon gas input volume reaches the maximum value simultaneously, the quick replacement process ends.

5. The method of using the device for improving the constant rate of the quick change process of the submerged nozzle in continuous casting according to claim 4, characterized in that, The first preset value is 1.2 m / min.

6. The method of using the device for improving the constant rate of the quick change process of the submerged nozzle in continuous casting according to claim 4, characterized in that, The second preset value is 0.6 m / min.

7. The method of using the device for improving the constant rate of the quick change process of the submerged nozzle in continuous casting according to claim 4, characterized in that, The third preset value is 0.4 m / min.

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