Laser vibration detection method and system for tundish shroud

Abstract

The present invention relates to the technical field of steelmaking and continuous casting, and specifically to a laser vibration detection method and system for a tundish long shroud. The laser Doppler effect non-contact measurement method is used to measure the tundish long shroud in a high-temperature state during operation, and a frequency amplitude curve of the tundish long shroud is obtained based on the measurement result; the frequency in the measured frequency amplitude curve is compared with the first frequency comparison table obtained by pre-simulation, and the length of the measured tundish long shroud is obtained according to the frequency matching state during the comparison; wherein, the first frequency comparison table is used to record the first-order wet modal resonance frequency of the tundish long shroud model of different lengths obtained by pre-simulation; wherein, the shorter the measured length of the tundish long shroud is, the more serious the wear condition of the tundish long shroud is. This method avoids the damage accident of the tundish long shroud, and also avoids the waste caused by the abandonment of the damaged tundish long shroud.

Description

Technical Field

[0001] The invention relates to the technical field of steelmaking and continuous casting, and in particular to a laser vibration detection method and system for a long shroud of a tundish. Background Art

[0002] With the development of continuous casting technology, in order to stabilize the quality of molten steel and reduce the consumption of refractory materials, the number of continuous casting furnaces is increasing. As the molten steel channel between the continuous casting tundish and the ladle, the life of the tundish shroud determines the upper limit of the number of continuous casting furnaces. In actual production, the tundish shroud will be damaged and cracked under the erosion of molten steel. The damage or cracks of the existing tundish shroud are observed and judged by the naked eye, but the high temperature environment greatly affects the accuracy of the observation and judgment. Therefore, the damage accident of the tundish shroud is difficult to avoid, which brings risks to production, equipment and personnel in the continuous casting process. In order to avoid the damage accident of the tundish shroud, steel mills usually adopt a very conservative number of continuous casting furnaces, resulting in a large number of tundish shrouds being abandoned before their service life, resulting in great waste. Even so, the damage accident of the tundish shroud is still difficult to avoid. Summary of the invention

[0003] The purpose of the present invention is to address the defects of the prior art and provide a laser vibration detection method and system for the long nozzle of the tundish, which can realize automatic detection of damage to the long nozzle of the tundish, has high safety and high detection accuracy.

[0004] The present invention provides a laser vibration detection method for a tundish long nozzle, and its technical solution is as follows:

[0005] The laser Doppler effect non-contact measurement method is used to measure the tundish shroud in a high-temperature state during operation, and the frequency amplitude curve of the tundish shroud is obtained based on the measurement results.

[0006] The frequency in the measured frequency amplitude curve is compared with the first frequency comparison table obtained by pre-simulation, and the length of the long shroud of the measured tundish is obtained according to the frequency matching state during the comparison;

[0007] Wherein, the first frequency comparison table is used to record the first-order wet modal resonance frequency of the tundish long nozzle model with different lengths obtained by pre-simulation;

[0008] Among them, when the measured length of the tundish shroud is shorter, it is judged that the wear condition of the tundish shroud is more serious.

[0009] More preferably, it also includes

[0010] The frequency in the measured frequency amplitude curve is compared with the second frequency comparison table obtained by pre-simulation, and the crack morphology of the tundish shroud under test is obtained according to the frequency matching state during the comparison;

[0011] The second frequency comparison table is used to record the first-order wet modal resonance frequency of the tundish shroud model under different crack forms obtained by pre-simulation.

[0012] Preferably, the non-contact measurement method using the laser Doppler effect to measure the tundish shroud in a high-temperature state during operation includes:

[0013] A high temperature resistant reflective mark is provided on the outer wall of the tundish shroud;

[0014] During the pouring phase of the tundish, a laser vibration measuring device is used to emit a laser beam toward the reflective mark for irradiation until a specified time is reached.

[0015] Preferably, the frequency amplitude curve of the tundish shroud obtained based on the measurement results includes:

[0016] Based on the data measured by the laser vibration measuring device, the speed and time mileage curve of the tundish shroud is drawn;

[0017] Differentiating the speed and time mileage curve to obtain the acceleration and practical mileage curve of the tundish shroud;

[0018] The acceleration and practical mileage curve is subjected to fast Fourier transformation to obtain a frequency amplitude curve of the tundish shroud.

[0019] Preferably, the first frequency comparison table is obtained by simulation by the following method:

[0020] Use the wet modal calculation module to build models for tundish shrouds of different lengths;

[0021] Calculate the resonance frequency of the first-order wet mode of the tundish shroud model with different lengths;

[0022] Enter the lengths of the tundish shroud and the corresponding resonance frequencies into the first frequency comparison table;

[0023] Among them, the corresponding tundish shroud length can be obtained by matching the frequency with the first frequency comparison table, and the matched tundish shroud length is the length of the tundish shroud to be measured.

[0024] Preferably, the second frequency comparison table is obtained by simulation by the following method:

[0025] Using the wet modal calculation module, models are established for each tundish shroud with common cracks;

[0026] Calculate the resonance frequency of the first-order wet mode of different tundish shroud models with common cracks;

[0027] Enter each crack shape and corresponding resonance frequency of the tundish shroud into the second frequency comparison table;

[0028] Among them, the crack morphology of the corresponding tundish shroud can be obtained by matching the frequency with the second frequency comparison table;

[0029] The common cracks are common cracks that occur in the tundish shroud during operation, and the common cracks are obtained based on statistical analysis of historical crack data of the tundish shroud.

[0030] More preferably, it also includes

[0031] Using the wet modal calculation module, the model of each tundish shroud with the same crack morphology at different heights is established;

[0032] Enter the heights of each crack of the tundish shroud and the corresponding resonance frequencies into the third frequency comparison table;

[0033] After obtaining the crack morphology of the tundish shroud by matching with the second frequency comparison table, the height of the crack on the tundish shroud is obtained by matching the frequency with the third frequency comparison table.

[0034] The present scheme also provides a system for implementing the above method, which is provided with a reflective mark on the outer surface of the long water nozzle of the tundish, and a laser vibration measuring device is provided on one side of the long water nozzle of the tundish. The laser emission port of the laser vibration measuring device is used to emit a laser beam along the horizontal direction, and the laser beam corresponds to the reflective mark. The data output end of the laser vibration measuring device is connected to a computer, and the reflective mark is formed by a high temperature resistant coating.

[0035] Preferably, reflective marks are symmetrically provided on the left and right sides of the outer surface of the long water outlet of the tundish.

[0036] Preferably, the reflective mark is circular, the diameter of the reflective mark is 0.8-1.2 cm, and the reflective mark is higher than the cover of the tundish.

[0037] The beneficial effects of the present invention are:

[0038] 1. This scheme uses the laser Doppler effect non-contact measurement method to measure the long nozzle of the tundish in a high-temperature state during operation, and obtains the frequency amplitude curve of the long nozzle of the tundish based on the measurement results; the frequency in the measured frequency amplitude curve is compared with the first frequency comparison table obtained by pre-simulation, and the length of the measured long nozzle of the tundish is obtained according to the frequency matching state during the comparison; wherein, the first frequency comparison table is used to record the first-order wet modal resonance frequency of the tundish long nozzle model of different lengths obtained by pre-simulation. After measuring the length of the tundish long nozzle, the wear state of the tundish long nozzle can be judged, which avoids the damage accident of the tundish long nozzle. It also avoids the waste caused by the tundish long nozzle being abandoned due to the damage accident.

[0039] 2. Use the wet modal calculation module to build models for each tundish shroud with common cracks; calculate the resonance frequency of the first-order wet modal of different tundish shroud models with common cracks; enter each crack morphology of the tundish shroud and the corresponding resonance frequency into the second frequency comparison table; wherein, the crack morphology of the corresponding tundish shroud can be obtained through the frequency matched with the second frequency comparison table. This further avoids the damage accident of the tundish shroud and improves production safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic flow chart of an embodiment of a laser vibration detection method for a tundish shroud of the present invention;

[0041] Figure 2 It is a schematic flow chart of another embodiment of a laser vibration detection method for a tundish shroud of the present invention;

[0042] Figure 3 It is a front view schematic diagram of a laser vibration detection system for a tundish shroud of the present invention;

[0043] Figure 4 It is a schematic diagram of the position of the reflective mark and the tundish cover of a laser vibration detection system of a tundish long nozzle of the present invention;

[0044] Figure 5 It is a top view schematic diagram of a laser vibration detection system for a tundish shroud of the present invention;

[0045] Figure 6 This is the relationship between the first-order response frequency and the length of the shroud in the modal calculation of the shroud;

[0046] Figure 7 This is the relationship between the sixth-order response frequency and the length of the long nozzle in the long nozzle modal calculation.

[0047] In the figure: 1-long shroud of tundish, 2-steel ladle, 3-tundish, 4-laser vibration measuring device, 5-laser beam, 6-computer, 7-reflective mark, 8-tundish cover. DETAILED DESCRIPTION

[0048] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0049] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0051] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0052] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0053] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0054] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0055] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0056] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include a particular feature, structure or characteristic described in conjunction with the embodiment. Therefore, the phrases "in one embodiment", "in some other embodiments", "in other embodiments", etc. appearing in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized. "Multiple" means "two or more"

[0057] Embodiment 1

[0058] The present invention provides a laser vibration detection method for the tundish shroud. It can be concluded from simulation calculations and physical experiments that during the operation of the tundish 3, the tundish shroud 1 is eroded by molten steel, the length of the tundish shroud 1 is continuously shortened from the lower shroud, and the resonance frequency is continuously increased. Therefore, by measuring the resonance frequency of the tundish shroud 1 during operation, the erosion condition of the tundish shroud 1 during operation can be determined. Figure 1 As shown, this embodiment specifically describes the solution for the damage detection of the tundish shroud, and its technical solution is as follows:

[0059] The laser Doppler effect non-contact measurement method is used to measure the tundish shroud in a high-temperature state during operation, and the frequency amplitude curve of the tundish shroud is obtained based on the measurement results.

[0060] The frequency in the measured frequency amplitude curve is compared with the first frequency comparison table obtained by pre-simulation, and the length of the long shroud of the measured tundish is obtained according to the frequency matching state during the comparison;

[0061] Wherein, the first frequency comparison table is used to record the first-order wet modal resonance frequency of the tundish long nozzle model with different lengths obtained by pre-simulation;

[0062] Among them, when the measured length of the tundish shroud is shorter, it is judged that the wear condition of the tundish shroud is more serious.

[0063] The first frequency comparison table is simulated by the following method:

[0064] The wet modal calculation module in ANSYS Workbench was used to build models for tundish shrouds of different lengths.

[0065] Calculate the resonance frequency of the first-order wet mode of the tundish shroud model with different lengths;

[0066] The lengths of the long shroud of the tundish and the corresponding resonance frequencies are entered into the first frequency comparison table.

[0067] Preferably, the non-contact measurement method using the laser Doppler effect to measure the tundish shroud in a high-temperature state during operation includes:

[0068] Before the tundish is operated, two circular high-temperature resistant reflective marks 7 with a diameter of 1 cm are set on the outer surface of the tundish long nozzle 1 at symmetrical positions of the axis of the tundish long nozzle 1. The center of the reflective mark 7 is on the upper part of the tundish 3 cover, and the vertical distance from the tundish 3 cover is 0.1m. The center of the laser emission hole of the laser vibration measuring device 4 and the center of the two reflective marks 7 are set on the same horizontal line, and the optimal distance between the laser vibrometer 4 and the reflective mark 7 is set according to the specific parameters of the laser vibration measuring device 4. During the tundish pouring stage, the laser beam 5 of the laser vibration measuring device 4 is irradiated on the reflective mark 7 on the tundish long nozzle. Each of the two reflective marks 7 is irradiated with a laser beam for 10 seconds, and the results measured by the laser vibration measuring device 4 are imported into the computer 6.

[0069] Preferably, the frequency amplitude curve of the tundish shroud obtained based on the measurement results includes:

[0070] Computer 6 draws a speed and time mileage curve of the long water nozzle of the tundish based on the data measured by the laser vibration measuring device; differentiates the speed and time mileage curve to obtain the acceleration and practical mileage curve of the long water nozzle of the tundish; performs fast Fourier transform on the acceleration and practical mileage curve to obtain the frequency amplitude curve of the long water nozzle of the tundish.

[0071] Among them, by comparing the frequency in the frequency amplitude curve with the first frequency comparison table, a matching frequency can be obtained, thereby obtaining the corresponding tundish long shroud length, and the matched tundish long shroud length is the length of the tundish long shroud being measured.

[0072] More preferably, as the tundish shroud is gradually eroded by the molten steel during operation, its bottom will be gradually worn, causing the length of the tundish shroud to become shorter. When the wear is light, the impact on production is small, while when the wear is heavy, the length of the tundish shroud is too short, which will have a greater impact on the continuous casting, and the tundish shroud needs to be replaced at this time. The length of the tundish shroud in the first frequency comparison table in this scheme covers the initial length of the tundish shroud to the minimum wear length, wherein the initial length of the tundish shroud is the length when it is not worn, and the minimum wear length is a set shortest length. Between the initial length of the tundish shroud and the minimum wear length, multiple length values ​​are selected according to the set spacing, wherein all discrete length values ​​constitute a continuous multiple range intervals. The initial length of the tundish shroud to the first length threshold is set as a safety interval, and when the measured length is in this safety interval, it is considered that the measured tundish shroud can still be used. The first length threshold to the second length threshold are set as a low-risk interval. When the measured length is in the low-risk interval, it is considered that the measured tundish shroud has certain hidden dangers at the current moment and needs to be replaced after the current round of production is completed. At this time, the controller outputs a flashing light alarm. The second length threshold to the minimum wear length is set as a high-risk interval. It is considered that the measured tundish shroud has a large hidden danger at the current moment and needs to terminate the current round of production and immediately replace the tundish shroud. At the same time, the controller outputs a flashing light and a beeping alarm.

[0073] Preferably, in production, there may be a situation where the long water nozzle of the tundish is asymmetrically worn, such as one side is worn to a greater extent, while the other side is worn. At this time, the overall length of the long water nozzle of the tundish is still normal, but there are still major hidden dangers, and it still needs to be identified. In response to this situation, this solution adopts the method of symmetrically setting reflective marks and laser vibration measuring devices on the left and right sides of the long water nozzle of the tundish, measuring the left and right sides of the long water nozzle of the tundish at the same time, and comparing them with the first frequency comparison table respectively. Through comparison, if the length of one side of the long water nozzle of the tundish is in the safe range, but the length of the other side is in the low-risk or high-risk range, a corresponding alarm is still required to prompt the staff to replace it.

[0074] Embodiment 2

[0075] Since the tundish shroud 1 is flushed by molten steel for a long time, cracks will appear inside. According to the wet modal calculation and physical experimental results, it can be concluded that as the size of the crack inside the tundish shroud 1 gradually increases, the resonance frequency decreases. Therefore, the resonance frequency of the tundish shroud 1 during operation is measured. Figure 2 As shown, this embodiment specifically describes the solution for crack morphology detection of the tundish shroud, and its technical solution is as follows:

[0076] The laser Doppler effect non-contact measurement method is used to measure the tundish shroud in a high-temperature state during operation, and the frequency amplitude curve of the tundish shroud is obtained based on the measurement results.

[0077] The frequency in the measured frequency amplitude curve is compared with the second frequency comparison table obtained by pre-simulation, and the crack morphology of the tundish shroud under test is obtained according to the frequency matching state during the comparison;

[0078] Wherein, the second frequency comparison table is used to record the first-order wet modal resonance frequency of the tundish long nozzle model under different crack forms obtained by pre-simulation;

[0079] The second frequency comparison table is simulated by the following method:

[0080] Using the wet modal calculation module in ANSYS Workbench software, models were established for each tundish shroud with common cracks;

[0081] Calculate the resonance frequency of the first-order wet mode of different tundish shroud models with common cracks;

[0082] Enter each crack shape and corresponding resonance frequency of the tundish shroud into the second frequency comparison table;

[0083] Among them, the crack morphology of the corresponding tundish shroud can be obtained by matching the frequency with the second frequency comparison table;

[0084] The common cracks are common cracks that occur in the tundish shroud during operation, and the common cracks are obtained based on statistical analysis of historical crack data of the tundish shroud.

[0085] Preferably, the non-contact measurement method using the laser Doppler effect to measure the tundish shroud in a high-temperature state during operation includes:

[0086] Before the tundish is operated, two circular high-temperature resistant reflective marks 7 with a diameter of 1 cm are set on the outer surface of the tundish long nozzle 1 at symmetrical positions of the axis of the tundish long nozzle 1. The center of the reflective mark 7 is on the upper part of the tundish 3 cover, and the vertical distance from the tundish 3 cover is 0.1m. The center of the laser emission hole of the laser vibration measuring device 4 and the center of the two reflective marks 7 are set on the same horizontal line, and the optimal distance between the laser vibrometer 4 and the reflective mark 7 is set according to the specific parameters of the laser vibration measuring device 4. During the tundish pouring stage, the laser 5 of the laser vibration measuring device 4 is irradiated on the reflective mark 7 on the tundish long nozzle. Each of the two reflective marks 7 is irradiated with a beam of laser 5 for 10 seconds, and the results measured by the laser vibration measuring device 4 are imported into the computer 6.

[0087] Preferably, the frequency amplitude curve of the tundish shroud obtained based on the measurement results includes:

[0088] Computer 6 draws a speed and time mileage curve of the long water nozzle of the tundish based on the data measured by the laser vibration measuring device; differentiates the speed and time mileage curve to obtain the acceleration and practical mileage curve of the long water nozzle of the tundish; performs fast Fourier transform on the acceleration and practical mileage curve to obtain the frequency amplitude curve of the long water nozzle of the tundish.

[0089] Embodiment 3

[0090] After obtaining the crack morphology, the crack height can also be located by the method provided in this embodiment, as follows:

[0091] Using the wet modal calculation module, the model of each tundish shroud with the same crack morphology at different heights is established;

[0092] Enter the heights of each crack of the tundish shroud and the corresponding resonance frequencies into the third frequency comparison table;

[0093] After obtaining the crack morphology of the tundish shroud by matching with the second frequency comparison table, the height of the crack on the tundish shroud is obtained by matching the frequency with the third frequency comparison table.

[0094] Since the length, shape and height of the crack are different, their impact on the continuous casting process is different. This solution builds an alarm database based on the length, shape and height of the crack. When it is finally measured that there is a crack inside the long nozzle of the tundish, and any of the length, shape and height of the crack is within the range stored in the alarm database, an alarm is issued. This alarm is different from the other alarm forms of the damage alarm and is used to distinguish between damage and cracks.

[0095] Embodiment 4

[0096] like Figure 3-5 As shown, this embodiment also provides a system for implementing the above method, which is provided with a reflective mark 7 on the outer surface of the long water nozzle 1 of the tundish, and a laser vibration measuring device 4 is provided on one side of the long water nozzle 1 of the tundish. The laser emitting port of the laser vibration measuring device 4 is used to emit a laser beam along the horizontal direction, and the laser beam corresponds to the reflective mark 7. The data output end of the laser vibration measuring device 4 is connected to a computer 6, and the reflective mark 7 is formed by a high temperature resistant coating.

[0097] Preferably, reflective marks are symmetrically provided on the left and right sides of the outer surface of the long water outlet of the tundish.

[0098] Preferably, the reflective mark is circular, the diameter of the reflective mark is 0.8-1.2 cm, and the reflective mark is higher than the middle ladle cover 8 .

[0099] Embodiment 5

[0100] This embodiment takes a two-stream tundish of a steel plant as an example, wherein the length of the long nozzle is 1395 mm, the wall thickness is 40 mm, the top width is 185 mm, the lower part is a bell-mouth structure, and the width of the widest part of the bottom is 235 mm. Figure 4 As shown. Now we use the large commercial simulation software ANSYS to perform modal calculation on the shroud. According to the modal calculation requirements, the following assumptions are made for the modal calculation of the shroud:

[0101] The lining of the shroud is made of MgO as refractory material, and its density is 3580kg / m3;

[0102] The top of the long shroud is used as a fixed support;

[0103] According to the calculation results of the large-scale commercial simulation software ANSYS, as the shroud is eroded and shortened during operation, its low-order and high-order modal frequencies increase linearly with the reduction of the shroud length, such as Figure 6 and Figure 7 As shown in the figure, the first-order mode shows that the modal frequency increases by about 0.16% for every 1mm shortening of the shroud. Due to the small frequency change, the use of a high-precision laser Doppler vibration measurement device can effectively monitor the slight damage of the shroud during operation, allowing production personnel to more accurately grasp the working status of the shroud.

[0104] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0105] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A laser vibration detection method for a tundish shroud, characterized in that: include The laser Doppler effect non-contact measurement method is used to measure the tundish shroud in a high-temperature state during operation, and the frequency amplitude curve of the tundish shroud is obtained based on the measurement results. The frequency in the measured frequency amplitude curve is compared with the first frequency comparison table obtained by pre-simulation, and the length of the long shroud of the measured tundish is obtained according to the frequency matching state during the comparison; Wherein, the first frequency comparison table is used to record the first-order wet modal resonance frequency of the tundish long nozzle model with different lengths obtained by pre-simulation; Among them, when the measured length of the tundish shroud is shorter, it is judged that the wear condition of the tundish shroud is more serious; Also includes: The frequency in the measured frequency amplitude curve is compared with the second frequency comparison table obtained by pre-simulation, and the crack morphology of the tundish shroud under test is obtained according to the frequency matching state during the comparison; Wherein, the second frequency comparison table is used to record the first-order wet modal resonance frequency of the tundish long nozzle model under different crack forms obtained by pre-simulation; The non-contact measurement method using the laser Doppler effect to measure the tundish shroud in a high-temperature state during operation includes: A high temperature resistant reflective mark is provided on the outer wall of the tundish shroud; During the pouring phase of the tundish, a laser vibration measuring device is used to emit a laser beam toward the reflective mark for irradiation until a specified time is reached.

2. The laser vibration detection method for the tundish shroud according to claim 1 is characterized in that: The frequency amplitude curve of the tundish shroud obtained based on the measurement results includes: Based on the data measured by the laser vibration measuring device, the speed and time mileage curve of the tundish shroud is drawn; Differentiating the speed and time mileage curve to obtain the acceleration and practical mileage curve of the tundish shroud; The acceleration and practical mileage curve is subjected to fast Fourier transformation to obtain a frequency amplitude curve of the tundish shroud.

3. The laser vibration detection method for the tundish shroud according to claim 1, characterized in that: The first frequency comparison table is obtained by simulation using the following method: Use the wet modal calculation module to build models for tundish shrouds of different lengths; Calculate the resonance frequency of the first-order wet mode of the tundish shroud model with different lengths; Enter the lengths of the tundish shroud and the corresponding resonance frequencies into the first frequency comparison table; Among them, the corresponding tundish shroud length can be obtained by matching the frequency with the first frequency comparison table, and the matched tundish shroud length is the length of the tundish shroud to be measured.

4. The laser vibration detection method for the tundish shroud according to claim 1, characterized in that: The second frequency comparison table is obtained by simulation using the following method: Using the wet modal calculation module, models are established for each tundish shroud with common cracks; Calculate the resonance frequency of the first-order wet mode of different tundish shroud models with common cracks; Enter each crack shape and corresponding resonance frequency of the tundish shroud into the second frequency comparison table; Among them, the crack morphology of the corresponding tundish shroud can be obtained by matching the frequency with the second frequency comparison table; The common cracks are common cracks that occur in the tundish shroud during operation, and the common cracks are obtained based on statistical analysis of historical crack data of the tundish shroud.

5. The laser vibration detection method for the tundish shroud according to claim 4 is characterized in that: Also includes Using the wet modal calculation module, the model of each tundish shroud with the same crack morphology at different heights is established; Enter the heights of each crack of the tundish shroud and the corresponding resonance frequencies into the third frequency comparison table; After obtaining the crack morphology of the tundish shroud by matching with the second frequency comparison table, the height of the crack on the tundish shroud is obtained by matching the frequency with the third frequency comparison table.

6. A system for implementing the method according to any one of claims 1 to 5, characterized in that: A reflective mark is provided on the outer surface of the long water nozzle of the tundish, and a laser vibration measuring device is provided on one side of the long water nozzle of the tundish. The laser emitting port of the laser vibration measuring device is used to emit a laser beam along the horizontal direction, and the laser beam corresponds to the reflective mark. The data output end of the laser vibration measuring device is connected to a computer, and the reflective mark is formed by a high temperature resistant coating.

7. The system according to claim 6, characterized in that: The outer surface of the long shroud of the tundish is symmetrically provided with reflective marks on the left and right sides.

8. The system according to claim 7, characterized in that: The reflective mark is circular, the diameter of the reflective mark is 0.8-1.2 cm, and the reflective mark is higher than the cover of the tundish.

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