Anti-pull-off and anti-leakage steel plug dummy ingot operation method of billet continuous casting machine

Abstract

The invention discloses an operation method for preventing a steel plug dummy ingot from being pulled out and leaking out of a square billet continuous casting machine, which comprises the following steps of: feeding a dummy ingot head into a crystallizer to a casting position, and then filling a gap between the crystallizer and the dummy ingot head with a sealing rope; an iron box is placed above a dummy bar head, a cold material is placed in the iron box, the iron box is a square frame body formed by bending an iron sheet, the iron box is placed in a crystallizer along the edge of a crystallizer copper pipe, the attaching degree of the iron sheet and the inner wall of the crystallizer copper pipe is larger than or equal to 95%, and looseness or wrinkles are avoided. The iron box is arranged on the inner wall of the crystallizer, the cold material is wrapped by the iron box, the copper pipe can be protected, and meanwhile the head casting blank shrinks to increase the restraining force. The iron box wraps the cold material, the iron sheet and the cold material can be synchronously and smoothly melted, the head solidification speed of a casting blank is increased, and the casting strength of the connecting piece is enhanced. By the adoption of the operation method, the motor starting current of the withdrawal and straightening machine is stable, the withdrawal force is stably output, and the cast-on pull-off breakout occurrence rate is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgy, in particular to a billet continuous casting machine anti-pulling and steel leakage plug dummy bar operation method. BACKGROUND

[0002] The continuous casting machine is one of the key links of quality control in a steel enterprise, and high quality, high efficiency and low cost are the development goals of the continuous casting machine. The continuous casting machine of the prior art often adopts four machines and four flows. After the casting machine dummy bar is sent into the crystallizer, the dummy head and the four around gaps of the crystallizer need to be blocked. Through reasonable pouring process, the high-temperature molten steel is prevented from flowing out through the four around gaps after being poured into the crystallizer, thereby preventing the blocking flow accident caused by the sticking of the dummy head and the pulling-off of the dummy bar and the leakage accident caused by the leakage of the molten steel, and further causing the fan-shaped section and the crystallizer to be taken offline for maintenance, the production to be forced to stop, the production efficiency to be reduced, and the cost loss to be increased.

[0003] Therefore, it is necessary to develop a method for preventing the leakage of the crystallizer, effectively prevent the leakage of the crystallizer, improve the production efficiency, and reduce the cost loss. SUMMARY

[0004] The present application aims to overcome the above-mentioned deficiencies of the prior art, and provides a billet continuous casting machine anti-pulling and steel leakage plug dummy bar operation method.

[0005] The technical problem of the present application is solved by adopting the following technical scheme.

[0006] The present application provides a billet continuous casting machine anti-pulling and steel leakage plug dummy bar operation method, which comprises the following steps: sending a dummy head into a crystallizer to a pouring position, and then filling a sealing rope into a gap between the crystallizer and the dummy head; placing an iron box above the dummy head and placing cold material in the iron box, wherein the iron box is a square frame body formed by bending an iron sheet, the iron box is placed in the crystallizer along the edge of a copper pipe of the crystallizer, and the fitting degree of the iron sheet and the inner wall of the copper pipe of the crystallizer is greater than or equal to 95%, without looseness or wrinkles.

[0007] The present application has the following beneficial effects:

[0008] The present application provides a billet continuous casting machine anti-pulling-out and leakage-steel-plug dummy bar operation method, which comprises: placing an iron box above the dummy bar head and placing cold material in the iron box, the iron box is a square frame body bent by iron sheet, the iron box is placed in the crystallizer along the edge of the crystallizer copper pipe, and the fitting degree of the iron sheet and the inner wall of the crystallizer copper pipe is greater than or equal to 95%, without looseness or wrinkle. The above operation method places an iron box along the inner wall of the crystallizer, which can protect the copper pipe, and the shrinkage of the head billet increases the restraint force. At the same time, the iron sheet can melt synchronously and smoothly with the cold material, the joint solidification effect is better, the opening pouring leakage dummy bar and pulling-out and flow interruption accident risk are reduced. The solidification speed of the head billet is increased, and the pulling strength of the connecting piece is enhanced. By using the above operation method, the motor starting current of the straightening machine is stable, and the pulling force is stable. The opening pouring pulling-out and leakage steel occurrence rate is greatly reduced. DETAILED DESCRIPTION

[0009] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be clearly and completely described below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased in the market.

[0010] The traditional plug dummy bar operation method has the following significant defects:

[0011] Dummy bar head structure defect: after opening pouring, the dummy bar head is prone to bifurcation, and when the dummy bar head comes out of the crystallizer, the bifurcated part will be stuck at the crystallizer foot roller, causing the pulling resistance to increase suddenly, which easily causes the dummy bar head to be pulled out of the billet.

[0012] The pulling resistance is too large: in the old operation method, the dummy bar head is sent into the crystallizer lower opening by 5 cm, which causes the friction resistance between the dummy bar head and the inner wall of the crystallizer to increase when the billet is pulled, so that the straightening machine current is too high, and long-term operation may cause motor overload or interruption of billet pulling.

[0013] Cold material design is unreasonable: the length of the cold material is 9-10 cm and the amount is 6 kg, and the overlong cold material is prone to form a "bridge" (cold materials support each other without close contact) in the crystallizer, which causes the molten steel to be unable to quickly impact the bottom of the dummy bar head, the molten steel at the head of the dummy bar head solidifies slowly and unevenly, and the risk of pulling-out and leakage of steel is increased.

[0014] The crystallizer is seriously damaged: the cold material is prone to bifurcation during the pulling of the billet, which directly scratches (cuts) the crystallizer copper pipe, causing the crystallizer to be out of service, increasing the equipment maintenance cost (such as copper pipe replacement cost), and affecting the production efficiency due to downtime. Statistics show that the monthly average steel passing amount of the crystallizer under the old method is only 8200 tons, and the service life is relatively short.

[0015] In order to solve the problem of the connection between the dummy head and the casting blank in the pouring process, the operation process of the plug dummy is optimized, the cold material parameters are improved, the special auxiliary tool is introduced, and the intelligent monitoring and self-adaptive adjusting system is added, so that a new anti-pulling and anti-steel leakage operation method is formed, which can effectively prevent the leakage of steel, improve the production efficiency and reduce the cost loss.

[0016] The billet continuous casting machine anti-pulling and anti-steel leakage plug dummy operation method provided by the embodiment of the application will be described in detail.

[0017] The application provides a billet continuous casting machine anti-pulling and anti-steel leakage plug dummy operation method, and the specific steps are as follows:

[0018] 1. Dummy head positioning optimization and surface treatment

[0019] 1.1 After the dummy head is sent to the lower opening position of the crystallizer (not 5 cm inside the lower opening in the old method), stop, tightly fill the gap between the dummy head and the inner wall of the crystallizer with asbestos thread, and then tamp and fix after ensuring that there is no gap, so as to reduce the contact area between the dummy head and the crystallizer and reduce the pulling resistance.

[0020] 1.2 Special coating treatment is performed on the surface of the dummy head, and a porous metal buffer layer (thickness 2-3 mm, porosity 30%-40%) is additionally arranged on the surface, and high-temperature ceramic particles (such as Al2O3) are filled in the buffer layer. The structure can absorb the instantaneous impact force in the pulling process through the elastic deformation of the porous layer, reduce the stress concentration at the connection position between the dummy head and the casting blank, and at the same time, the ceramic particles enhance the wear resistance to avoid the bifurcation of the dummy head.

[0021] 2. Special iron sheet auxiliary device and material improvement

[0022] 2.1 A special iron sheet is customized according to the inner diameter size of the copper pipe of the crystallizer, the iron sheet is folded into a square matching the inner cavity of the crystallizer, and the iron sheet is placed into the crystallizer along the edge of the copper pipe of the crystallizer and is tightly knocked with a tool to make the iron sheet tightly adhere to the inner wall of the crystallizer, so as to form a closed "containing cavity". The iron sheet and the inner wall of the crystallizer are filled with asbestos cloth and iron filings, which can effectively reduce the occurrence of steel leakage.

[0023] 2.2 The thickness of the iron sheet is 0.3-0.5 mm, the warping degree is ≤1 mm / m, and the material is selected to be low-alloy steel with a silicon content of 1.2%-1.5%. Compared with the traditional low-carbon steel, the melting speed of the low-alloy steel at high temperature is more easily matched with the solidification rhythm of the molten steel. At the same time, a layer of boron-based high-temperature release agent with a thickness of 0.1-0.2 mm is brushed on the inner side of the iron sheet. The release agent forms a protective film to prevent the cold material from being excessively adhered to the iron sheet, so that after the molten steel is poured, the iron sheet can be melted synchronously and smoothly with the cold material, and the uneven distribution of the cold material caused by adhesion is avoided.

[0024] 3. Cold material parameter improvement and component optimization

[0025] 3.1 The length of the cold charge is reduced from 9-10 cm to 6-7 cm, and the amount is reduced from 6 kg to 5 kg; the cold charge is evenly placed in the "containing cavity" formed by the iron sheet, and is flattened with tools to ensure that the cold charge is not stacked and bridged.

[0026] 3.2 The composition of the cold charge is optimized by adding 0.05%-0.08% niobium element based on the original composition. The niobium element can refine the grain structure of the cold charge, improve the high temperature strength and toughness of the cold charge, and make the cold charge not easy to break or bifurcate during the subsequent drawing process, further ensuring the uniform distribution and stable solidification of the cold charge.

[0027] 4. Intelligent monitoring and adaptive adjustment system

[0028] 4.1 Multiple infrared temperature sensors are installed on the outer wall of the crystallizer to monitor the temperature changes at different positions in the crystallizer in real time, with a temperature measurement accuracy of ±2℃. At the same time, a torque sensor is installed on the output shaft of the drawing and straightening motor to monitor the change of the drawing torque in real time.

[0029] 4.2 The data of the temperature sensor and the torque sensor are transmitted to the central control system, which analyzes and judges according to the preset temperature threshold and torque threshold. When an abnormal temperature rise in a certain area or the drawing torque exceeds the set threshold is detected, the system automatically sends a warning signal and adjusts the drawing speed (adjustment range ±0.1 m / min) and the cooling water quantity of the crystallizer (adjustment range ±5%) to realize adaptive adjustment, ensuring the stability of the drawing process. For example, when it is found that the temperature of one side of the crystallizer is too high, the system will automatically increase the cooling water quantity of that side to reduce the local temperature and prevent damage to the crystallizer or poor solidification of the cold charge due to local overheating.

[0030] 5. Pouring operation and dynamic adjustment

[0031] 5.1 After completing the above steps, start pouring. After the molten steel is poured into the crystallizer, the iron sheet and the cold charge are melted synchronously at high temperature to form a uniformly solidified joint, which smoothly exits the crystallizer during the drawing process.

[0032] 5.2 During the pouring process, the operator can view the changes of various parameters in real time through the display screen of the central control system, and the drawing rhythm and dynamic adjustment mechanism are as follows:

[0033] Initial drawing speed: the drawing speed is controlled at 0.3-0.4 m / min within the first minute after pouring, and gradually increased to 0.5-0.6 m / min in the second and third minutes to avoid incomplete solidification of the cast blank due to too fast drawing speed;

[0034] Torque and current linkage control: real-time monitoring of the tension levelling motor torque in the range of 100-18N.m, and the current is 60%-80% of the rated current, when the torque exceeds the threshold value 200N.m or the current is more than 80%, the system automatically reduces the tension speed by 0.1m / min, while increasing the cooling water volume by 5%; if it is not restored within 30 seconds, trigger the sound and light alarm and prompt manual intervention;

[0035] Temperature field uniformity control: monitor the temperature difference around the crystallizer by infrared sensor, allow deviation ≤50℃, if the temperature of a side exceeds the threshold value, increase the cooling water volume of that side alone, adjust the range by 3%-5%, prevent local overheating from causing copper pipe damage or slab peeling.

[0036] 5.3 During the starting process, the molten steel injection parameters in the tundish are controlled:

[0037] Initial flow: within 30 seconds before starting, the molten steel injection flow is controlled at 60%-70% of the normal flow, to avoid excessive steel impact causing cold material displacement or shell deformation;

[0038] Liquid level control: the crystallizer liquid level adopts "stepwise rising" mode, the initial liquid level is controlled at 1 / 3 height, after 1-1.5 minutes, the cold material and shell begin to melt, gradually increase to 2 / 3 height, to prevent liquid level from rising suddenly causing overflow or insufficient solidification;

[0039] Temperature matching: the molten steel inlet temperature needs to be 20-30℃ higher than the liquidus temperature, to ensure moderate steel flowability and good fusion with cold material and shell.

[0040] 5.4 Also includes emergency treatment during the process of drawing the blank:

[0041] Minor leakage warning: when the bottom temperature of the crystallizer is abnormally high or the torque fluctuates slightly, immediately reduce the tension speed to 0.2m / min, while adding sealing rope to the edge of the crystallizer, the length is 5-10cm, and increase the cooling intensity;

[0042] Serious leakage disposal: if molten steel seeps out, immediately stop pouring and cut off the power supply of the tension levelling motor, use the emergency leakage treatment package to plug the leakage point, and then process after the molten steel solidifies, to avoid the accident from expanding.

[0043] The application will be further described below in conjunction with examples.

[0044] Preparation before starting

[0045] To ensure the stability of the starting process, the following preparations need to be completed before implementing the core operation steps, to reduce risks from the source:

[0046] Comprehensive inspection of equipment status

[0047] Crystallizer inspection: clean the inner wall of the crystallizer copper tube, ensure that there is no residual cold steel, scale or foreign matter, use special gauges to detect the amount of wear on the inner wall (allowable deviation ≤0.5mm), ensure the smoothness of the inner wall (Ra≤1.6μm); check the crystallizer cooling waterway, ensure that the inlet and outlet water pressure is stable (0.4-0.6MPa), the flow is uniform (deviation ≤3%), there is no blockage or water leakage.

[0048] Dummy bar system inspection: verify the operation state of the dummy bar rod driving device (motor, speed reducer), test the output torque of the straightening motor (fluctuation ≤5% when empty); check the fastening degree of the dummy bar head connecting bolt, ensure that the dummy bar head and the rod body have no relative shaking.

[0049] Intelligent monitoring system calibration: high temperature calibration is performed on the infrared temperature sensor (800-1500℃ standard heat source is used), to ensure that the measurement error is ≤±2℃; the torque sensor needs to be tested repeatedly 3 times under rated load, the data consistency deviation is ≤3%; the central control system simulates early warning triggering (such as setting the temperature threshold to 1200℃, the torque threshold to 200N·m), verifies the automatic adjustment function (response time of the blank drawing speed and the cooling water volume ≤2s).

[0050] Material pretreatment and quality control

[0051] The thickness of the iron sheet used to prepare the iron box is 0.3-0.5mm, the warping degree is ≤1mm / m, the material is low alloy steel containing 1.2%-1.5% silicon, the iron sheet is filled with asbestos cloth and iron filings between the inner wall of the crystallizer, and the inner side of the iron sheet is also coated with a boron-based high-temperature resistant coating with a thickness of 0.1-0.2mm, which is naturally air-dried for more than 4 hours after coating, to ensure that the coating has no bubbles.

[0052] The length of the cold material used is shortened from the original 9-10cm to 6-7cm, and the composition of the cold material is configured as follows: 0.05%-0.08% niobium element is added on the basis of the original composition, and internal ferromagnetic impurities (diameter ≥0.5mm) are removed by magnetic separation.

[0053] Coating material: the porous metal buffer layer is prefabricated by powder metallurgy process (porosity 30%-40%), and the Al2O3 ceramic particles filled inside need to be sieved (particle size 0.1-0.3mm), to ensure that the coating thickness is uniform (2-3mm, deviation ≤0.2mm).

[0054] Sealing rope: high-temperature resistant ceramic fiber rope (diameter 5-8mm) is selected, and is dried in a 100-120℃ oven for 2 hours in advance (to remove moisture), to avoid the failure of gap sealing due to water vapor evaporation when pouring.

[0055] Dummy bar head installation

[0056] Confirm the length of the ingot, and then push the ingot head to the position below the crystallizer. Fill the gap with asbestos wire and tamp it repeatedly until there is no gap. Record the position parameters of the ingot head.

[0057] Check the integrity of the ceramic coating on the surface of the ingot head. If the coating is damaged, repair it immediately or replace the ingot head.

[0058] Iron sheet placement

[0059] Fold the iron sheet into a square and slowly place it along the inner wall of the crystallizer copper tube. Use a long handle tool to knock the edge of the iron sheet from the top to ensure that the iron sheet adheres to the inner wall by ≥95%, without looseness or wrinkles. At the same time, ensure that the release agent is evenly distributed on the inside of the iron sheet.

[0060] Cold material placement

[0061] Place the cold material into the iron sheet in 2-3 times. After each placement, use a flat tool to flatten it to ensure that the cold material layer is uniform in thickness (about 3-4 cm) and there is no local accumulation.

[0062] Intelligent system deployment and debugging

[0063] Install the infrared temperature sensor evenly on the preset position of the outer wall of the crystallizer to ensure that it can monitor the temperature change inside the crystallizer comprehensively. Install the torque sensor on the output shaft of the straightening motor and connect the data transmission line.

[0064] Start the central control system, calibrate the sensor, set the temperature threshold and torque threshold parameters, and perform system trial operation to ensure that all functions are normal.

[0065] Key points of control during casting

[0066] The casting process is a critical stage for preventing steel leakage. Precise control is needed to ensure that the steel solidification matches the casting rhythm:

[0067] Steel injection parameter control

[0068] Initial flow rate: Within 30 seconds before casting, the steel injection flow rate is controlled at 60%-70% of the normal flow rate (e.g., if the design flow rate is 2 t / min, the initial flow rate is 1.2-1.4 t / min) to avoid excessive steel impact that may cause cold material displacement or iron sheet deformation.

[0069] Liquid level control: The crystallizer liquid level uses a "step-up" mode, with the initial liquid level controlled at 1 / 3 of the height (about 300 mm). After the cold material and iron sheet start to melt (about 1 minute), gradually raise it to 2 / 3 of the height (about 600 mm) to prevent liquid level from rising suddenly, which may cause overflow or insufficient solidification.

[0070] Temperature matching: the temperature of molten steel entering the station should be 20-30℃ higher than the liquidus temperature (for example, the liquidus temperature of Q235 steel is 1510℃, and the entering station temperature is controlled at 1530-1540℃), to ensure that the molten steel has moderate fluidity and forms good fusion with the cold material and iron skin.

[0071] Dynamic adjustment of drawing rhythm

[0072] Initial drawing speed: the drawing speed is controlled at 0.3-0.4 m / min in the first minute after pouring, and gradually increased to 0.5-0.6 m / min (70% of the normal drawing speed) in the second to third minutes to avoid incomplete solidification of the casting blank due to too fast drawing speed.

[0073] Torque and current linkage control: real-time monitoring of the torque (normal range 100-180 N·m) and current (60%-80% of the rated current) of the drawing and straightening motor, when the torque exceeds the threshold value 200 N·m or the current exceeds 80%, the system automatically reduces the drawing speed by 0.1 m / min, and increases the cooling water volume by 5%; if it does not return to normal within 30 seconds, trigger the audible and light alarm and prompt manual intervention.

[0074] Temperature field uniformity control: monitor the temperature difference around the crystallizer (allowable deviation ≤50℃) by infrared sensor, if the temperature of a side is too high (such as more than 1300℃), increase the cooling water volume of that side alone (adjustment range 3%-5%) to prevent local overheating causing copper pipe damage or casting blank shell off.

[0075] Emergency treatment mechanism

[0076] Minor leakage warning: when the temperature at the bottom of the crystallizer is abnormally high (more than 1000℃) or the torque fluctuates slightly, immediately reduce the drawing speed to 0.2 m / min, add sealing rope (length 5-10 cm) to the edge of the crystallizer, and increase the cooling intensity.

[0077] Serious leakage treatment: if the molten steel seeps out (visible sparks or smoke), immediately stop pouring and cut off the power supply of the drawing and straightening motor, use the emergency leakage treatment package to plug the leakage point, and after the molten steel solidifies, process it offline to avoid the accident from expanding.

[0078] The following table shows the differences between the old and new operation methods and the advantages of the new operation method.

[0079]

[0080]

[0081] Through the above technical improvements, the invention realizes the multiple effects of "reducing accidents, improving efficiency, prolonging life, and ensuring safety" in the pouring stage of square billet continuous casting, and has significant economic benefits and promotional value.

[0082] Compared with the prior art, the scheme provided by the application has the following characteristics and advantages:

[0083] 1. Significantly reduce the accident rate

[0084] The new operation method avoids the phenomenon of diverging and clamping the roll by restraining the shape of the cold material, shortening the length of the cold material, optimizing the composition of the cold material, and intelligent monitoring and adjusting. After application in November 2023, the number of monthly pouring joint leakage connections is reduced from 8 to 2, with a reduction of 75%, completely solving the core problem of pulling off and leaking steel. At the same time, due to the optimization of the composition of the cold material and the real-time monitoring of the intelligent system, the solidification of the cold material is more uniform and stable, further reducing the risk of various accidents caused by cold material problems.

[0085] 2. Prolong the service life of the crystallizer

[0086] The cold material is isolated from the copper pipe of the crystallizer by the iron sheet, which avoids the cold material scratching the copper pipe, and the intelligent monitoring system precisely controls the temperature of the crystallizer, reducing the damage to the crystallizer caused by local overheating. The monthly average steel passing amount of the crystallizer is increased from 8200t to 10890t, the service life is prolonged by 32.8%, the number of unplanned shutdowns is reduced, and the cost of equipment replacement is saved. The ceramic coating on the surface of the dummy bar also reduces the wear of the inner wall of the crystallizer, indirectly prolonging the service life of the crystallizer.

[0087] 3. Stabilize the drawing process

[0088] The combined action of dummy bar positioning optimization, surface coating treatment and cold material parameter improvement greatly reduces the drawing resistance. The current fluctuation range of the drawing and straightening motor is reduced by 40%, and the current value can be stably controlled within 60%-80% of the rated current, avoiding equipment failure caused by high current and ensuring the continuity and stability of the drawing process. The intelligent self-adaptive adjustment system can adjust the drawing speed and cooling water amount in real time according to the real-time working condition, further ensuring the stability of the drawing process.

[0089] 4. Improve the safety of operation

[0090] The reduction of accidents reduces the frequency of manual handling of accidents, and the risk of operators contacting high-temperature molten steel and equipment failure is reduced, which meets the safety production specifications. The early warning function of the intelligent monitoring system can also allow operators to predict potential risks in advance and take timely measures to avoid accidents, providing a safer working environment for operators.

[0091] 5. Universality and ease of use

[0092] The special iron sheet can be adapted to different specifications of crystallizers, the operation steps are simple, 48 existing post personnel have mastered, no additional equipment investment is needed, and the transformation cost is low. The intelligent monitoring and self-adaptive adjustment system adopts a humanized operation interface, and an operator can operate skillfully after simple training, and is convenient for popularization and application in production of various bloom continuous casting machines.

[0093] The above are only preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A billet continuous casting machine anti-pull-out leakage steel plug ingot operation method, characterized in that, Includes the following steps: The siphon head is fed into the crystallizer to the pouring position, and then the gap between the crystallizer and the siphon head is filled with sealing rope. An iron box is placed above the ingot head, and cold material is placed inside the iron box. The iron box is a square frame made of sheet metal bent into shape. The iron box is placed into the crystallizer along the edge of the copper tube of the crystallizer, and the fit between the sheet metal and the inner wall of the copper tube of the crystallizer is ≥95%, without looseness or wrinkles.

2. The billet continuous casting machine anti-pull-out leakage steel plug ingot operation method according to claim 1, characterized in that, To insert the ingot head into the crystallizer to the pouring position, insert the ingot head into the lower opening of the crystallizer. The sealing rope should be a high-temperature resistant ceramic fiber rope with a diameter of 5-8mm, which needs to be dried in an oven at 100-120℃ to remove moisture.

3. The billet continuous casting machine anti-pull-out leakage steel plug ingot operation method according to claim 2, characterized in that, Also includes: A coating is sprayed onto the surface of the ingot head. The coating is a porous metal buffer layer with a thickness of 2-3 mm and a porosity of 30%-40%. The interior is filled with high-temperature resistant ceramic particles with a particle size of 0.1-0.3 mm.

4. The billet continuous casting machine anti-pull-out leakage steel plug ingot operation method according to claim 1, characterized in that, The sheet metal used to prepare the iron box has a thickness of 0.3-0.5 mm and a warpage of ≤1 mm / m. The material is low alloy steel with a silicon content of 1.2%-1.5%. Asbestos cloth and iron filings are filled between the sheet metal and the inner wall of the crystallizer. The inner side of the sheet metal is also coated with a boron-based high-temperature resistant coating with a thickness of 0.1-0.2 mm. After coating, it is naturally dried for more than 4 hours to ensure that the coating is free of bubbles.

5. The billet continuous casting machine anti-pull-out leakage steel plug ingot operation method according to claim 1, characterized in that, The length of the cold material used has been shortened from the original 9-10cm to 6-7cm, and the composition of the cold material is configured as follows: 0.05%-0.08% niobium element is added to the original composition.

6. The billet continuous casting machine anti-pull-out leakage steel plug ingot operation method according to claim 5, characterized in that, The cold material feeding process includes: placing the cold material into the sheet metal in 2-3 batches, and flattening it with a flat tool after each batch to ensure that the cold material layer is of uniform thickness and without local accumulation. The preferred thickness of the cold material layer is 3-4 cm.

7. The billet continuous casting machine anti-pull-out leakage steel plug ingot operation method according to claim 1, characterized in that, Also includes: Install an infrared temperature sensor at a suitable location on the outer wall of the crystallizer, install a torque sensor on the output shaft of the straightening motor, and connect the infrared temperature sensor and the torque sensor to the central control system.

8. The billet continuous casting machine anti-pull-out leakage steel plug ingot operation method according to claim 7, characterized in that, The throwing rhythm and dynamic adjustment mechanism are as follows: Initial casting speed: The casting speed should be controlled at 0.3-0.4 m / min in the first minute after casting begins, and gradually increased to 0.5-0.6 m / min in the second and third minutes to avoid incomplete solidification of the billet due to excessive casting speed; Torque and current linkage control: Real-time monitoring of the tensioning motor torque within the range of 100-18 N·m and the current within 60%-80% of the rated current. When the torque exceeds the threshold of 200 N·m or the current exceeds 80%, the system automatically reduces the tensioning speed by 0.1 m / min and increases the cooling water volume by 5%. If the system does not return to normal within 30 seconds, an audible and visual alarm is triggered, prompting manual intervention. Temperature field uniformity control: The temperature difference around the crystallizer is monitored by infrared sensors. The allowable deviation is ≤50℃. If the temperature on a certain side exceeds the threshold, the cooling water volume on that side is increased separately. The adjustment range is 3%-5% to prevent local overheating from causing damage to the copper tube or billet delamination.

9. The billet continuous casting machine anti-pull-out leakage steel plug ingot operation method according to claim 1, characterized in that, Also includes: Controlling the parameters of molten steel injection into the ladle: Initial flow rate: Within 30 seconds before pouring, the molten steel injection flow rate is controlled at 60%-70% of the normal flow rate to avoid excessive impact of molten steel causing displacement of cold material or deformation of the sheet metal. Liquid level control: The liquid level in the crystallizer adopts a "step-up" mode. The initial liquid level is controlled at 1 / 3 of the height. After 1-1.5 minutes, when the cold material and iron sheet begin to melt, it is gradually raised to 2 / 3 of the height to prevent the liquid level from rising suddenly, which could lead to overflow or insufficient solidification. Temperature matching: The temperature of molten steel entering the station needs to be 20-30℃ higher than the liquidus temperature to ensure that the molten steel has moderate fluidity and forms a good fusion with cold materials and iron sheets.

10. The billet continuous casting machine anti-pull-out leakage steel plug ingot operation method according to claim 9, characterized in that, Also includes: Emergency handling during the throwing process: Minor steel leakage warning: When an abnormal increase in temperature at the bottom of the crystallizer or a slight fluctuation in torque is detected, immediately reduce the casting speed to 0.2m / min, add sealing ropes to the edge of the crystallizer with a length of 5-10cm, and increase the cooling intensity; Handling of severe steel leakage: If molten steel seepage occurs, immediately stop pouring and disconnect the power supply to the straightening motor. Use an emergency steel leakage treatment bag to seal the leak point. Wait for the molten steel to solidify before taking the line out of service to prevent the accident from escalating.

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