Adjusting device and method for submersed nozzle of slab continuous casting machine

Abstract

The invention relates to the technical field of ferrous metallurgy, in particular to an adjusting device and an adjusting method for a submersed nozzle of a slab caster, the submersed nozzle comprises a submersed nozzle, a slag line area is arranged on the surface of the submersed nozzle, the wall thickness of the slag line area is 35-37 mm, and the thickness of the slag line area is 20-30 mm. The slag line area is prepared from, by mass, 4%-13% of aluminum oxide, 78%-91% of zirconium oxide and 5%-12% of carbon. The material and wall thickness of the slag line area of the submersed nozzle are improved, so that when the tundish is cast and the controller controls the oil cylinder to work to drive the tundish to float up and down, automatic slag line changing of the nozzle is completed, the nozzle floating up and down can effectively enable molten steel to erode the whole surface of the slag line area, the service life of the submersed nozzle is prolonged, and the service life of the submersed nozzle is prolonged. The service life of the submersed nozzle is matched with the service life of the tundish, certain replacement cost and replacement time are reduced, the effects of reducing cost and increasing efficiency are achieved, and meanwhile the safety risk existing in midway replacement is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of iron and steel metallurgy, and in particular to an adjusting device and an adjusting method for an immersed nozzle of a slab continuous casting machine. Background Art

[0002] With the continuous development of industrial technology and the accelerating pace of steelmaking production, people have higher and higher requirements for the quality of ingots. Billets are generally produced by billet continuous casting machines. Slab continuous casting machines mainly include: tundish, submerged nozzle and crystallizer. Among them, the submerged nozzle, as one of the three major parts of continuous casting, is a key refractory casing for pouring in the continuous casting process. It is installed at the bottom of the tundish and inserted below the molten steel level of the crystallizer. It has the functions of preventing oxidation and splashing of molten steel, regulating the flow state of molten steel in the crystallizer and preventing slag rolling. Because the submerged nozzle is inserted below the molten steel level of the crystallizer, it is alternately scour and eroded by molten steel and protective slag, and the refractory material is continuously dissolved and peeled off, gradually forming a nozzle slag line.

[0003] At present, when molten steel is poured, it is poured from the large ladle into the tundish and then into the crystallizer. During this period, the height at which the bottom submerged nozzle of the tundish is inserted into the crystallizer remains unchanged, so that the slag line remains unchanged. However, the service life of the tundish is 14 hours, and the average life of the submerged nozzle with a fixed slag line is only about 8 hours. Therefore, when the submerged nozzle is used in conjunction with the tundish according to time, it is necessary to replace the submerged nozzle midway, which not only leads to high costs, but also poses certain safety risks when replacing it midway.

[0004] In addition, many steel mills use manual methods to change the slag line in their slab continuous casting machines. During the steelmaking production process of the slab continuous casting machine, the slag line of the submerged nozzle cannot be adjusted manually and accurately in a timely manner, which often leads to excessive erosion of the submerged nozzle in the crystallizer, seriously affecting the service life of the submerged nozzle, shortening the service life of the nozzle, and further increasing the cost of steelmaking production. Summary of the invention

[0005] The present invention provides a slab submerged nozzle and a use method thereof to solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: A slab submerged nozzle comprises a submerged nozzle, wherein a slag line area is arranged on the surface of the submerged nozzle, the wall thickness of the slag line area is 35-37 mm, and the mass percentage of the material components of the slag line area is: 4-13% aluminum oxide, 78-91% zirconium oxide, and 5-12% carbon.

[0007] Preferably, the wall thickness of the slag line area is 36 mm.

[0008] Preferably, the slag line area material contains 7% aluminum oxide, 85% zirconium oxide and 8% carbon.

[0009] The technical solution of the present application also provides a regulating device for a submerged nozzle of a slab continuous casting machine, comprising a submerged nozzle, a tundish, a crystallizer, a first oil cylinder, a second oil cylinder and a controller; the submerged nozzle adopts the submerged nozzle described above; The top end of the submerged water inlet is used to be connected to the bottom of the tundish, the bottom end of the submerged water inlet is used to be immersed in the molten steel in the crystallizer, and the controller is used to control the first oil cylinder and the second oil cylinder to drive the tundish to float up and down.

[0010] Preferably, the regulating device also includes a detection and measuring device and an HMI screen, wherein the detection and measuring device is used to detect and measure the up and down floating of the submerged water nozzle in the molten steel in the crystallizer, and the HMI screen is electrically connected to the controller and is used to display the up and down floating information of the submerged water nozzle.

[0011] The technical solution of the present application also provides a method for adjusting the submerged nozzle of a slab continuous casting machine, the adjustment method comprising the following steps: Step S100, before the tundish starts pouring, determine that the depth of the submerged nozzle inserted into the molten steel of the crystallizer is in the middle of the slag line area of ​​the submerged nozzle; Step S200, setting a range of depth changes of the slag line area of ​​the submerged nozzle inserted into the molten steel of the crystallizer and setting an alarm threshold after the slag line area of ​​the submerged nozzle floats up and down; Step S300, when the tundish is poured, the tundish is controlled to float up and down, so that the slag line area of ​​the submerged nozzle can be automatically changed within a set range; When the tundish floats and the insertion depth of the submerged nozzle is lower than or higher than the alarm threshold, the HMI screen displays an alarm prompt, and the controller synchronously controls the tundish to stop floating, so as to realize the automatic stop of the slag line change in the slag line area of ​​the submerged nozzle; Step S400: The tundish stays for 7 minutes when it rises to the highest value of the set range of the slag line area of ​​the submerged nozzle and when it falls to the lowest value of the set range of the slag line area of ​​the submerged nozzle.

[0012] Preferably, in step S200, the insertion depth of the slag line area of ​​the submerged nozzle varies in the range of 120-180 mm.

[0013] Preferably, in step S400, the tundish stays for 7 minutes when it rises to 180 mm or falls to 120 mm.

[0014] Preferably, the alarm threshold of the slag line area of ​​the submerged nozzle is that the insertion depth of the submerged nozzle is lower than 100 mm or higher than 200 mm.

[0015] Preferably, in step S300, the tundish floats according to the control of the first oil cylinder and the second oil cylinder, and the first oil cylinder and the second oil cylinder control the stroke by adjusting hydraulic parameters through a controller, so as to accurately and standardize the insertion depth of the submerged nozzle.

[0016] By adopting the above technical solution, the beneficial effects achieved by the present invention are: In the present invention, by improving the material and wall thickness of the slag line area of ​​the submerged water nozzle, when the tundish starts to be poured, the controller controls the oil cylinder to drive the tundish to float up and down, and the tundish can drive the submerged water nozzle to float up and down, so that the automatic slag line of the water nozzle is completed when the submerged water nozzle floats up and down. Compared with the slag line height that remains unchanged and erodes a fixed position, the water nozzle that floats up and down can effectively make the molten steel erode the entire surface of the slag line area, thereby improving the service life of the submerged water nozzle.

[0017] In the present invention, by stopping for 7 minutes when the tundish is raised to 180mm or lowered to 120mm, the submerged nozzle is used in this way, which can further increase the service life due to the improvement of the material and wall thickness in the slag line area, and promote the submerged nozzle to be increased from the original 8 hours to 14 hours, ensuring that the service life of the submerged nozzle matches the service life of the tundish, reducing a certain amount of replacement cost and replacement time, achieving the effect of reducing costs and increasing efficiency, and also avoiding the safety risks of mid-term replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the device of the present invention; Figure 2 It is a schematic diagram of the structure of the submerged nozzle of the present invention; Figure 3 Schematic diagram of the circuit of the present invention.

[0019] In the figure: 1. Immersed nozzle; 2. Slag line area; 3. Tundish; 4. Crystallizer; 5. First oil cylinder; 6. Second oil cylinder; 7. Controller; 8. Detection and measurement equipment; 9. HMI screen. DETAILED DESCRIPTION

[0020] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0022] like Figure 1-3As shown, the present invention provides an immersed water inlet, including an immersed water inlet 1, a slag line area 2 is arranged on the surface of the immersed water inlet 1, the wall thickness of the slag line area 2 is 35-37mm, and the mass percentage of the material components of the slag line area 2 is: 4-13% aluminum oxide, 78-91% zirconium oxide, and 5-12% carbon.

[0023] As a further preferred solution, the wall thickness of the slag line area 2 is 36 mm. By increasing the wall thickness of the slag line area 2 of the submerged water nozzle 1, it is possible to effectively increase the service life of the submerged water nozzle 1, make the service life of the submerged water nozzle 1 equal to that of the tundish 3, and reduce costs and increase efficiency.

[0024] As a further preferred solution, the mass content of aluminum oxide in the material of the slag line zone 2 is 7%, the mass content of zirconium oxide is 85%, and the mass content of carbon is 8%.

[0025] The technical solution of the present application provides a regulating device for an immersion nozzle of a slab continuous casting machine, comprising an immersion nozzle 1, a tundish 3, a crystallizer 4, a first oil cylinder 5, a second oil cylinder 6 and a controller 7; the immersion nozzle 1 adopts the immersion nozzle provided in the above; The top end of the submerged water nozzle 1 is used to be connected to the bottom of the tundish 3, and the bottom end of the submerged water nozzle 1 is used to be immersed in the molten steel in the crystallizer 4, and the controller 7 is used to control the first oil cylinder 5 and the second oil cylinder 6 to drive the tundish 3 to float up and down.

[0026] As a further preferred embodiment, the adjustment device also includes a detection and measurement device 8 and an HMI screen 9. The detection and measurement device 8 is used to detect and measure the up and down floating of the submerged water nozzle 1 in the molten steel in the crystallizer 4. The HMI screen 9 is electrically connected to the controller 7 and is used to display the up and down floating information of the submerged water nozzle 1.

[0027] Furthermore, the pipelines of the first oil cylinder 5 and the second oil cylinder 6 need to change their existing thick diameters into thin diameters, and valves need to be added on each pipeline. The valves can be divided into proportional valves and enabling control valves, and proportional valves and enabling valves are correspondingly installed on the pipelines of each oil cylinder. Then, the hydraulic parameters are adjusted according to the controller 7, so that the first oil cylinder 5 and the second oil cylinder 6 work slowly, effectively ensuring the accurate value of the cylinder controlling the ladle 3 to drive the submerged water nozzle 1 to float up and down, avoiding the phenomenon of the submerged water nozzle 1 being inserted too deep or too shallow, and ensuring the stability of on-site operations and product quality.

[0028] Furthermore, the first oil cylinder 5, the second oil cylinder 6, the controller 7, the detection and measuring equipment 8 and the HMI screen 9 can form an operating system, and the operating system also includes an intermediate ladle car operating box, wherein the controller 7 is a PLC controller, which is electrically connected to the HMI screen 9 and connected to the intermediate ladle car operating box through a communication cable, and the intermediate ladle car operating box is respectively connected to each cylinder enabling valve and cylinder proportional valve through a signal cable to control the slow operation of the oil cylinder, ensure that the intermediate ladle 3 drives the submerged water inlet 1 to float slowly, and avoid the phenomenon that the submerged water inlet 1 is inserted too deep or too shallow.

[0029] It should be noted that the above-mentioned cylinder enabling valve and cylinder proportional valve are well known to those skilled in the art and can be purchased, and this scheme does not make any structural improvements thereto. At the same time, the working speed control of the first cylinder 5 and the second cylinder 6 based on adjusting hydraulic parameters is also a technology well known to those skilled in the art and can be operated and applied, and this article will not elaborate on this in detail.

[0030] The technical solution of the present application provides a method for adjusting an immersed nozzle of a slab continuous casting machine, and the adjustment method comprises the following steps: Step S100, before the tundish 3 is poured, according to the parameter information measured by the detection and measurement equipment 8, it is determined that the depth value of the submerged nozzle 1 at the bottom of the tundish 3 inserted into the molten steel of the crystallizer 4 is in the middle of the slag line area 2 of the submerged nozzle 1; Step S200, setting the range of depth change of the slag line area 2 of the submerged nozzle 1 inserted into the molten steel of the crystallizer 4 and setting the alarm threshold after the slag line area 2 of the submerged nozzle 1 floats up and down according to the operation of the controller 7; Step S300, when the tundish 3 starts pouring, after the speed of pulling the ingot out of the crystallizer 4 reaches the target pulling speed, the operating system controls the tundish 3 to float up and down, so as to realize the automatic slag line change of the slag line area 2 of the submerged nozzle 1 within the set range value; When the tundish 3 floats and the insertion depth of the submerged nozzle 1 is lower than or higher than the alarm threshold, an alarm prompt is displayed on the HMI screen 9 in the operating system, and the controller 7 in the operating system synchronously controls the first oil cylinder 5 and the second oil cylinder 6 to stop moving, so that the first oil cylinder 5 and the second oil cylinder 6 drive the tundish 3 to stop floating, and the slag line area 2 of the submerged nozzle 1 automatically stops changing to the slag line; Step S400, the tundish 3 stays for 7 minutes when it rises to the highest value of the setting range of the slag line area 2 of the submerged nozzle 1 and falls to the lowest value of the setting range of the slag line area 2 of the submerged nozzle 1.

[0031] As a further preferred solution, in step S200, the insertion depth of the slag line area 2 of the submerged nozzle 1 varies in the range of 120-180 mm, that is, the minimum depth of the slag line area 2 of the submerged nozzle 1 is set to 120 mm, and the maximum depth is set to 180 mm.

[0032] As a further preferred solution, in step S400, the tundish 3 stays for 7 minutes when it rises to 180 mm or falls to 120 mm.

[0033] As a further preferred scheme, the alarm threshold of the slag line area 2 of the submerged water nozzle 1 is when the insertion depth of the submerged water nozzle 1 is lower than 100 mm or higher than 200 mm, and when the floating of the tundish 3 causes the insertion depth of the submerged water nozzle 1 to be lower than 100 mm or higher than 200 mm, an alarm prompt will be displayed on the HMI screen 9 in the operating system.

[0034] It should be noted that the overall height of the slag line area 2 of the submerged nozzle 1 is greater than 200 mm. When the slag line area 2 is located at the alarm threshold of 100 mm or 200 mm, a certain slag line area 2 is left at the top and bottom of the slag line area 2, which effectively ensures the use of the submerged nozzle 1.

[0035] As a further preferred solution, in step S300, the tundish 3 is floated according to the control of the first oil cylinder 5 and the second oil cylinder 6, and the first oil cylinder 5 and the second oil cylinder 6 control the stroke by adjusting the hydraulic parameters through the controller 7, so as to accurately and standardize the insertion depth of the submerged water nozzle 1.

[0036] Among them, the pipelines of the first oil cylinder 5 and the second oil cylinder 6 need to change their existing thick diameters into thin diameters, and valves (valves can be divided into proportional valves and enabling control valves) are added on each pipeline respectively, and proportional valves and enabling valves are installed on the pipelines of each oil cylinder accordingly, and then the hydraulic parameters are adjusted according to the controller 7, so that the first oil cylinder 5 and the second oil cylinder 6 work slowly, effectively ensuring the accurate value of the oil cylinder controlling the ladle 3 to drive the submerged water nozzle 1 to float up and down, avoiding the phenomenon of the submerged water nozzle 1 being inserted too deep or too shallow, and ensuring the stability of on-site operation and product quality.

[0037] Furthermore, when the first oil cylinder 5 and the second oil cylinder 6 work to drive the tundish 3 to float up and down, the detection and measuring equipment 8 is used to detect the up and down lifting height of the submerged nozzle 1 driven by the tundish 3, that is, to detect the slag line area 2; and the detection and measuring equipment 8 is an existing conventional equipment, and can be detected by sensors. Generally, the types of sensors can be ultrasonic, infrared, and ray types; in the embodiment of the present disclosure, a radioactive source Co60 is used to detect and obtain the above-mentioned measurement parameter information; and this scheme does not make structural improvements to its detection and measuring equipment 8, so the conventional detection and measuring equipment 8 can be installed and used according to the operations familiar to those skilled in the art, and this article will not elaborate on it. Example

[0038] An immersed water inlet comprises an immersed water inlet 1, a slag line area 2 is arranged on the surface of the immersed water inlet 1, the wall thickness of the slag line area 2 is 36 mm, and the mass percentage of the material components of the slag line area 2 is: 10% aluminum oxide, 78% zirconium oxide, and 12% carbon. This embodiment corresponds to scheme two. Example

[0039] An immersed nozzle comprises an immersed nozzle 1, a slag line area 2 is arranged on the surface of the immersed nozzle 1, the wall thickness of the slag line area 2 is 36 mm, and the mass percentage of the material components of the slag line area 2 is: 12% aluminum oxide, 80% zirconium oxide, and 8% carbon. This embodiment corresponds to scheme four. Example

[0040] An immersed nozzle comprises an immersed nozzle 1, a slag line area 2 is arranged on the surface of the immersed nozzle 1, the wall thickness of the slag line area 2 is 36 mm, and the mass percentage of the material components of the slag line area 2 is: 10% aluminum oxide, 82% zirconium oxide, and 8% carbon. This embodiment corresponds to scheme five. Example

[0041] An immersed water inlet comprises an immersed water inlet 1, wherein a slag line area 2 is arranged on the surface of the immersed water inlet 1, wherein the wall thickness of the slag line area 2 is 36 mm, and the mass percentage of the material components of the slag line area 2 is: 7% aluminum oxide, 85% zirconium oxide, and 8% carbon. This embodiment corresponds to scheme six. Example

[0042] An immersed water inlet comprises an immersed water inlet 1, wherein a slag line area 2 is arranged on the surface of the immersed water inlet 1, wherein the wall thickness of the slag line area 2 is 36 mm, and the mass percentage of the material components of the slag line area 2 is: 4% aluminum oxide, 88% zirconium oxide, and 8% carbon. This embodiment corresponds to scheme seven. Example

[0043] A submerged water inlet comprises a submerged water inlet 1, wherein a slag line area 2 is arranged on the surface of the submerged water inlet 1, wherein the wall thickness of the slag line area 2 is 36 mm, and the mass percentage of the material components of the slag line area 2 is: 4% aluminum oxide, 90% zirconium oxide, and 6% carbon. This embodiment corresponds to scheme eight.

[0044] The slag line area 2 prepared by using various material contents in Examples 1 to 6 was tested for use, and the test results are shown in Table 1: Table 1 Slag line area use test results

[0045] According to the test results in Table 1 above, when increasing the zirconium oxide content for testing, the pouring time of Scheme 6 is up to 12 hours, and the pouring time is not improved when the zirconium oxide content is further increased. Therefore, it is finally confirmed that Scheme 6 has a better effect and meets the use requirements.

[0046] In summary, the submerged nozzle 1 adopted in the above embodiments, the adjustment method of the submerged nozzle of the slab continuous casting machine includes the following steps: Step S100, before the tundish 3 is poured, according to the parameter information measured by the detection and measurement equipment 8, it is determined that the depth value of the submerged nozzle 1 at the bottom of the tundish 3 inserted into the molten steel of the crystallizer 4 is in the middle of the slag line area 2 of the submerged nozzle 1; Step S200, setting the range of depth change of the slag line area 2 of the submerged nozzle 1 inserted into the molten steel of the crystallizer 4 and setting the alarm threshold after the slag line area 2 of the submerged nozzle 1 floats up and down according to the operation of the controller 7; Among them, the insertion depth of the slag line area 2 of the submerged nozzle 1 varies from 120 to 180 mm; The alarm threshold of the slag line area 2 of the submerged nozzle 1 is that the insertion depth of the submerged nozzle 1 is lower than 100 mm or higher than 200 mm.

[0047] Step S300, when the tundish 3 starts pouring, after the speed of pulling the ingot out of the crystallizer 4 reaches the target pulling speed, the operating system controls the tundish 3 to float up and down, so as to realize the automatic slag line change of the slag line area 2 of the submerged nozzle 1 within the set range value; When the tundish 3 floats and the insertion depth of the submerged nozzle 1 is lower than 100 mm or higher than 200 mm, an alarm prompt is displayed on the HMI screen 9, and the controller 7 synchronously controls the first oil cylinder 5 and the second oil cylinder 6 to stop moving, so that the first oil cylinder 5 and the second oil cylinder 6 drive the tundish 3 to stop floating, and the slag line area 2 of the submerged nozzle 1 automatically stops changing to the slag line; Step S400, the tundish 3 is kept for 7 minutes when it rises to 180 mm or falls to 120 mm.

[0048] When the tundish 3 is poured, the controller 7 in the operating system controls the first oil cylinder 5 and the second oil cylinder 6 to drive the tundish 3 to float up and down at 120-180mm, and then the tundish 3 drives the submerged nozzle 1 to float up and down at 120-180mm, so that the immerged nozzle 1 can automatically change the slag line when floating up and down. Compared with the slag line height that remains unchanged and erodes a fixed position, the up and down floating nozzle can effectively make the molten steel erode the entire surface of the slag line area 2, thereby increasing the service life of the submerged nozzle 1. According to actual tests, the use of the tundish 3 to increase the height of the slag line 2 can effectively improve the service life of the submerged nozzle 1. When it reaches 180mm or drops to 120mm, it stays for 7 minutes respectively. When the submerged nozzle 1 is used in this way, the service life can be further increased by improving the material and wall thickness. The increased service life can be as long as 2 hours. Combined with the slag line area 2 of the submerged nozzle 1 proposed in this solution, during pouring, the submerged nozzle 1 can be increased from the original 8 hours to 14 hours, so that the service life of the submerged nozzle 1 and the tundish 3 are matched, and a certain replacement cost and replacement time are reduced, so as to achieve the effect of reducing costs and increasing efficiency, and at the same time avoid the safety risks of replacement in the middle.

[0049] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An adjusting device for an immersed nozzle of a slab continuous casting machine, characterized in that: The invention comprises an immersion nozzle (1), a tundish (3), a crystallizer (4), a first oil cylinder (5), a second oil cylinder (6) and a controller (7), wherein the top end of the immersion nozzle (1) is used to be connected to the bottom of the tundish (3), the bottom end of the immersion nozzle (1) is used to be immersed in the molten steel in the crystallizer (4), and the controller (7) is used to control the first oil cylinder (5) and the second oil cylinder (6) to drive the tundish (3) to float up and down, and a slag line area (2) is provided on the surface of the immersion nozzle (1), the wall thickness of the slag line area (2) is 35-37 mm, and the mass percentage of the material components of the slag line area (2) is: 4-13% of aluminum oxide, 78-91% of zirconium oxide, and 5-12% of carbon.

2. The regulating device for the submerged nozzle of the slab continuous casting machine according to claim 1, characterized in that: The wall thickness of the slag line area (2) is 36 mm.

3. The regulating device for the submerged nozzle of the slab continuous casting machine according to claim 1, characterized in that: The material of the slag line area (2) contains 7% aluminum oxide, 85% zirconium oxide and 8% carbon.

4. The regulating device for the submerged nozzle of the slab continuous casting machine according to claim 1, characterized in that: It also includes a detection and measurement device (8) and an HMI screen (9), wherein the detection and measurement device (8) is used to detect and measure the up and down floating of the submerged nozzle (1) in the molten steel in the crystallizer (4), and the HMI screen (9) is electrically connected to the controller (7) and is used to display the up and down floating information of the submerged nozzle (1).

5. A method for adjusting a submerged nozzle of a slab continuous casting machine according to any one of claims 1 to 4, characterized in that: The adjustment method includes the following steps: Step S100, before the tundish (3) starts pouring, determine that the depth of the submerged nozzle (1) inserted into the molten steel of the crystallizer (4) is located in the middle of the slag line area (2) of the submerged nozzle (1); Step S200, setting a range of depth changes of the slag line area (2) of the submerged nozzle (1) inserted into the molten steel of the crystallizer (4) and setting an alarm threshold after the slag line area (2) of the submerged nozzle (1) floats up and down; Step S300, when the tundish (3) starts to be poured, the tundish (3) is controlled to float up and down, so that the slag line area (2) of the submerged nozzle (1) can automatically change the slag line within a set range value; When the tundish (3) floats so that the insertion depth of the submerged nozzle (1) is lower than or higher than the alarm threshold, the HMI screen (9) displays an alarm prompt, and the controller (7) synchronously controls the tundish (3) to stop floating, thereby automatically stopping the slag line area (2) of the submerged nozzle (1) and changing the slag line operation; Step S400, the tundish (3) stays for 7 minutes when it rises to the highest value of the setting range of the slag line area (2) of the submerged nozzle (1) and when it falls to the lowest value of the setting range of the slag line area (2) of the submerged nozzle (1).

6. The method for adjusting the submerged nozzle of a slab continuous casting machine according to claim 5, characterized in that: In the step S200, the insertion depth of the slag line area (2) of the submerged nozzle (1) varies in the range of 120-180 mm.

7. The method for adjusting the submerged nozzle of a slab continuous casting machine according to claim 6, characterized in that: In step S400, the tundish (3) stays for 7 minutes when it rises to 180 mm or falls to 120 mm.

8. The method for adjusting the submerged nozzle of a slab continuous casting machine according to claim 5, characterized in that: The alarm threshold of the slag line area of ​​the submerged nozzle (1) is that the insertion depth of the submerged nozzle (1) is less than 100 mm or greater than 200 mm.

9. The method for adjusting the submerged nozzle of a slab continuous casting machine according to claim 5, characterized in that: In step S300, the tundish (3) is floated according to the control of the first oil cylinder (5) and the second oil cylinder (6), and the first oil cylinder (5) and the second oil cylinder (6) are controlled by adjusting hydraulic parameters through the controller (7) to control the stroke, thereby accurately and standardizedly controlling the insertion depth of the submerged nozzle (1).

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