Method for prolonging service life of tundish

Abstract

The invention relates to the technical field of continuous casting, in particular to a method for prolonging the service life of a tundish, by improving the geometrical shape of a retaining wall, additionally arranging an air blowing component on the lower middle portion of the retaining wall, optimizing pouring parameters and controlling the correlation of the pouring parameters, the flow characteristic of molten steel can be remarkably improved, impact on the retaining wall and the surrounding area is reduced, and the service life of the tundish is prolonged. Therefore, the service life of the tundish is prolonged, the maintenance cost is reduced, and strong support is provided for stability and high efficiency of the continuous casting process.

Description

Technical Field

[0001] The invention relates to the technical field of continuous casting, in particular to a method for increasing the service life of a tundish. Background Art

[0002] In the modern steelmaking process, continuous casting technology, as a key process, has greatly improved production efficiency and steel quality. However, the service life of the continuous casting tundish has always been one of the important challenges faced by the industry. The retaining wall of the tundish is usually subjected to the strong impact force from the high-speed molten steel, resulting in rapid wear and damage of the material. Therefore, how to effectively extend the service life of the tundish, reduce maintenance costs, and improve production efficiency is the key research direction of researchers in this field. However, traditional research directions have failed to fully consider the impact of molten steel flow on the retaining wall, and have failed to solve the life problem of the retaining wall and its surrounding areas. Summary of the invention

[0003] The present invention provides a method for improving the service life of a tundish, which optimizes the flow characteristics of molten steel, reduces the impact force and wear of the molten steel on a retaining wall and its surrounding areas, and significantly improves the service life of the tundish and the retaining wall.

[0004] According to one aspect of the present invention, the present invention provides the following technical solution: A method for increasing the service life of a tundish, comprising the following steps: S1. A retaining wall is arranged at the bottom of the tundish in the direction of the molten steel flowing out of the impact zone, and both ends of the retaining wall are connected to the tundish wall to form an enclosed space with the tundish wall at the side of the impact zone. Steel flow holes and a blowing component are arranged on the retaining wall, and the blowing component is used to blow air into the molten steel in the enclosed space; S2. Control the blowing direction and blowing flow of the blowing parts, and control the position of the long nozzle during pouring to increase the service life of the tundish.

[0005] As a preferred embodiment of the method for increasing the service life of the tundish described in the present invention, in step S1, the cross-section of the retaining wall is a combination of at least two curved surfaces, and the curvature of the retaining wall is not greater than 0.8.

[0006] As a preferred embodiment of the method for increasing the service life of the tundish described in the present invention, in step S1, the top surface of the impact zone is a slope or an arc surface, and the angle between the top surface of the impact zone and the vertical direction is not less than 15°.

[0007] As a preferred embodiment of the method for increasing the service life of the intermediate package described in the present invention, in said step S1, the blowing component is arranged in the middle and lower part of the retaining wall; the blowing method is continuous blowing or intermittent blowing; the blowing component is a breathable brick, and the gas blown into the blowing component is argon.

[0008] As a preferred embodiment of the method for increasing the service life of the tundish described in the present invention, in said step S1, the total area of ​​the steel flow holes arranged on the retaining wall does not exceed 30% of the area of ​​the retaining wall; the total area of ​​the blowing components arranged on the retaining wall does not exceed 45% of the area of ​​the retaining wall.

[0009] As a preferred embodiment of the method for increasing the service life of the tundish described in the present invention, in step S1, the length of the retaining wall does not exceed 60% of the length between the two ends of the inner wall of the tundish in the direction of the long axis.

[0010] As a preferred solution of the method for increasing the service life of the tundish described in the present invention, in the step S1, the thickness of the upper and middle part of the retaining wall is adjusted to 1.2 to 3 times the thickness of the existing retaining wall.

[0011] As a preferred solution of the method for increasing the service life of the tundish according to the present invention, in step S2, the total blowing flow rate Q of the blowing component is: Where Q is the total air flow rate of the air blowing component, ranging from 500 to 2000 m 3 / h;Q steel is the flow rate of molten steel, ranging from 1×10 3 ~2×10 5 kg / h; ρ is the gas density, which is usually an inert gas such as argon and helium, and its value range is 0.17~1.8 kg / m 3 ; d is the depth of the shroud inserted into the molten steel during pouring, ranging from 10 to 200 mm; Δx is the horizontal offset of the shroud insertion position relative to the center of the pouring area away from the retaining wall during pouring, ranging from 0 to 160 mm; α is a dimensionless coefficient, usually an empirical value, ranging from -0.04 to 7.198×10 6 .

[0012] As a preferred solution of the method for increasing the service life of the tundish according to the present invention, in step S2, the angle θ between the blowing direction of the blowing component and the horizontal direction is: Among them, θ is the angle between the blowing direction of the blowing component and the horizontal direction, the tilt direction towards the gravity direction is negative, and the range is -60~60°; k is a dimensionless coefficient, usually an empirical value, and the value range is -3464~3464.

[0013] As a preferred embodiment of the method for improving the service life of the tundish described in the present invention, in step S2, the horizontal offset of the long nozzle insertion position away from the retaining wall relative to the center of the pouring area during pouring is 0.2 to 0.6 times the equivalent radius of the pouring area.

[0014] As a preferred embodiment of the method for increasing the service life of the tundish described in the present invention, in said step S2, the depth of the long nozzle inserted into the molten steel during pouring is 0.05 to 0.3 times the depth of the molten steel in the pouring area.

[0015] The beneficial effects of the present invention are as follows: The present invention provides a method for increasing the service life of a tundish. By improving the geometric shape of a retaining wall, adding a blowing component to the middle and lower part of the retaining wall, optimizing casting parameters and controlling their correlation, the flow characteristics of molten steel can be significantly improved, and the impact on the retaining wall and the surrounding area can be reduced, thereby extending the service life of the tundish, reducing maintenance costs, and providing strong support for the stability and efficiency of the continuous casting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0017] Figure 1 A top cross-sectional view of a tundish with a retaining wall installed according to the present invention; Figure 2 It is a schematic structural diagram of the enclosed space formed by the retaining wall and the intermediate bag wall at the side of the impact zone of the present invention; Figure 3 This is the erosion diagram of the original tundish after 69.16 hours of use; Figure 4 This is the erosion diagram after the tundish was used for 83.3 hours using the method of the present invention.

[0018] Description of Figure Numbers: 1-impact zone, 2a-retaining wall, 2b-blowing component, 2c-steel flow hole, 3-tundish, 4-steel outlet.

[0019] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0020] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The main purpose of the present invention is to provide a method for increasing the service life of a tundish, which has the following advantages: (1) Optimized flow design: By carefully designing the geometric shape of the retaining wall, adding air-permeable bricks, and optimizing the pouring parameters, the present invention effectively disperses and homogenizes the impact force of the molten steel. This optimization reduces the direct impact on the retaining wall, thereby reducing the wear rate, extending the service life of the tundish, ensuring a smoother flow of molten steel, and improving overall production efficiency.

[0022] (2) Application of air blowing technology: Air blowing technology is implemented in the middle and lower part of the retaining wall to change the flow characteristics of molten steel and significantly reduce the impact force. This innovation effectively reduces the wall pressure and turbulence intensity, and alleviates the erosion of the retaining wall.

[0023] (3) Coordination between parameters: The coordination between blowing angle, flow rate, pouring depth and position can optimize the flow of molten steel, reduce bubbles and defects, and improve the quality of molten steel. Optimizing these parameters can accelerate the pouring process, improve production efficiency, extend the service life of the tundish, reduce energy consumption, and ultimately improve the quality of molten steel and economic benefits.

[0024] (4) Reduce inclusion erosion: The gas effectively removes inclusions in the molten steel during its ascent, reducing the erosion of the retaining wall by inclusions. This cleaning effect not only improves the quality of the molten steel, but also protects the retaining wall material, thereby extending the overall service life of the tundish.

[0025] (5) Improved turbulence suppressor design: By changing the impact area of ​​the turbulence suppressor from a flat surface to a slope or arc surface, the flow path of the molten steel is optimized. This design significantly reduces turbulence and impact, and reduces damage to the retaining wall.

[0026] (6) Reduce maintenance costs: The present invention thickens the middle and upper areas of the retaining wall that are often eroded by the up and down movement of slag. Combined with other measures, it significantly increases the service life of the tundish retaining wall and reduces maintenance frequency and related costs. This economic benefit not only saves resources, but also improves production efficiency, bringing long-term benefits to the enterprise.

[0027] like Figure 1-2 As shown, an embodiment of the present invention provides a device for realizing a method for increasing the service life of a tundish, comprising: Impact zone 1, retaining wall 2a, blowing part 2b; The impact zone 1 is arranged at the bottom of the tundish 3 and below the long shroud, directly bearing the impact of the molten steel from the long shroud; the impact force of the molten steel is used to promote the rise and separation of inclusions; The retaining wall 2a is arranged at the bottom of the tundish 3 in the direction of the molten steel flowing out of the impact zone 1 and connected to the wall of the tundish 3 at both ends, forming an enclosed space with the wall of the tundish 3 at the side of the impact zone 1, and a steel flow hole 2c is arranged on the retaining wall 2a; The blowing component 2b is arranged on the retaining wall 2a, and is used for blowing air into the molten steel in the enclosed space.

[0028] The embodiment of the present invention also provides a method for increasing the service life of a tundish, comprising the following steps: S1. A retaining wall is arranged at the bottom of the tundish in the direction of the molten steel flowing out of the impact zone, and both ends of the retaining wall are connected to the tundish wall to form an enclosed space with the tundish wall at the side of the impact zone. Steel flow holes and a blowing component are arranged on the retaining wall, and the blowing component is used to blow air into the molten steel in the enclosed space; S2. Control the blowing direction and blowing flow of the blowing parts, and control the position of the long nozzle during pouring to increase the service life of the tundish.

[0029] In one embodiment of the present invention, in step S1, the cross-section of the retaining wall is a combination of at least two curved surfaces, and the curvature of the retaining wall is not greater than 0.8. In terms of the geometric shape optimization of the retaining wall, it is designed as a curved surface or a streamlined structure. This design not only improves the impact resistance of the retaining wall, but also reduces the unevenness during the flow of molten steel, thereby improving the overall flow characteristics. Traditional retaining walls usually adopt a planar structure, which is prone to local stress concentration, thereby aggravating wear. The use of a curved surface design can effectively reduce the impact strength of molten steel during the flow process. By converting the planar shape of the retaining wall into a streamlined surface, the flow direction of the molten steel can be changed when it contacts the retaining wall. This change effectively disperses the kinetic energy of the molten steel and reduces the direct impact force on the retaining wall. In addition, the curved surface design also helps to reduce flow resistance, thereby optimizing the flow efficiency of the molten steel. In the specific design, the radius and slope of the curved surface need to be accurately calculated according to the flow characteristics of the molten steel to ensure the best force effect.

[0030] In one embodiment of the present invention, in step S1, the top surface of the impact zone is a slope or arc surface, and the angle between the top surface of the impact zone and the vertical direction is not less than 15°. The original plane is changed to a slope or arc surface design, and a multi-stage slope impact zone is designed, which effectively improves the flow path of the molten steel and reduces the intensity of turbulence and impact. This design can not only reduce local turbulence and impact, but also optimize the overall flow state, so that the molten steel is more stable when passing through the turbulence suppressor, effectively reducing the wear of the retaining wall.

[0031] In one embodiment of the present invention, in step S1, a blowing component is arranged in the middle and lower part of the retaining wall; the blowing method is continuous blowing or intermittent blowing; the blowing component is a breathable brick, and the gas blown into the blowing component is argon. A blowing component is added in the middle and lower part of the retaining wall, and the function of the blowing component is to promote the flow of molten steel by blowing argon, thereby reducing the turbulent effect and reducing the impact force. The blowing component can effectively adjust the flow direction and speed of the molten steel in the turbulence suppressor. By adding a blowing component in the middle and lower part of the retaining wall, a more uniform airflow distribution can be achieved, and the dead zone of the flow can be reduced, thereby improving the overall flow stability of the molten steel. This stability not only reduces the impact on the retaining wall, but also effectively prevents the aggregation of bubbles and avoids the generation of inclusions. By blowing, the flow characteristics of the molten steel can be effectively changed. Blowing can not only reduce the direct impact force of the molten steel on the retaining wall, but also reduce the wall pressure and turbulence intensity. At the same time, this gas can bring the inclusions in the molten steel to the slag layer during the rising process, reducing the erosion of the inclusions on the retaining wall. This process not only reduces wear on the retaining wall material, but also increases the purity of the molten steel and improves the quality of the final product.

[0032] In one embodiment of the present invention, in step S1, the total area of ​​the steel flow holes arranged on the retaining wall does not exceed 30% of the area of ​​the retaining wall; the total area of ​​the blowing parts arranged on the retaining wall does not exceed 45% of the area of ​​the retaining wall; the length of the retaining wall does not exceed 60% of the length between the two ends of the inner wall of the tundish in the long axis direction. This setting can effectively adapt to tundishes of different sizes, thereby improving the adaptability of the equipment and the flexibility of operation. At the same time, it will also help to reduce production losses caused by size mismatch and improve overall production efficiency. The total area of ​​the blowing parts arranged on the retaining wall does not exceed 45% of the area of ​​the retaining wall to avoid excessive occupation of the effective space of the tundish; limiting the area of ​​the blowing parts also helps to ensure the structural stability of the retaining wall and avoid mechanical stress concentration or damage caused by too many blowing ports; at the same time, the appropriate area ratio helps to ensure the uniform distribution of the airflow in the tundish, avoid local overcooling or overheating, and thus improve the temperature and composition uniformity of the molten steel.

[0033] In one embodiment of the present invention, in step S1, the thickness of the middle and upper part of the retaining wall is adjusted to 1.2 to 3 times the thickness of the existing retaining wall. This design is intended to improve the durability and service life of the retaining wall, especially when the slag causes frequent wear on the retaining wall. The thickened retaining wall can effectively resist the impact and wear of the slag, extend its service life and reduce the frequency of maintenance. At the same time, the increase in thickness improves the overall stiffness and stability of the retaining wall, enabling it to better withstand the physical stress caused by the movement of slag. In addition, the thick wall design delays the fatigue failure of the material and improves the working reliability, thereby optimizing production efficiency and reducing the time of downtime for maintenance. Therefore, this thickening measure not only enhances the wear resistance of the retaining wall, but also significantly improves the safety and economy of production.

[0034] In one embodiment of the present invention, in step S2, the total blowing flow rate Q of the blowing component is: Where Q is the total air flow rate of the air blowing component, ranging from 500 to 2000 m 3 / h;Q steel is the flow rate of molten steel, ranging from 1×10 3 ~2×10 5 kg / h; ρ is the gas density, which is usually an inert gas such as argon and helium, and its value range is 0.17~1.8kg / m 3 ; d is the depth of the shroud inserted into the molten steel during pouring, ranging from 10 to 200 mm; Δx is the horizontal offset of the shroud insertion position relative to the center of the pouring area away from the retaining wall during pouring, ranging from 0 to 160 mm; α is a dimensionless coefficient, usually an empirical value, ranging from -0.04 to 7.198×10 6 .

[0035] In one embodiment of the present invention, in step S2, the angle θ between the blowing direction of the blowing component and the horizontal direction is: Among them, θ is the angle between the blowing direction of the blowing component and the horizontal direction, the tilt direction towards the gravity direction is negative, and the range is -60~60°; k is a dimensionless coefficient, usually an empirical value, and the value range is -3464~3464.

[0036] The present invention clarifies the relationship between the blowing angle in the tundish, the total blowing flow rate, the pouring depth and the pouring position, and their coordinated effect is crucial to the flow, temperature distribution and composition uniformity of the molten steel. The blowing angle determines the distribution of gas and the stirring intensity of the molten steel. A larger blowing angle helps to enhance stirring, but may increase bubble interference; while a smaller blowing angle helps to maintain the stability of the molten steel surface. The pouring depth affects the smoothness of the molten steel flow. A deeper pouring depth helps to reduce turbulence, while a shallower depth may cause excessive surface turbulence. The pouring position determines the flow pattern of the molten steel, and center pouring is conducive to the uniform distribution of the molten steel. The synergistic effect between the four needs to be adjusted according to the actual process. Reasonable blowing angles, flow rates, pouring depths and pouring positions can optimize the flow pattern of the molten steel, maintain good gas distribution and temperature uniformity, and thus improve smelting efficiency and molten steel quality.

[0037] In one embodiment of the present invention, in step S2, the horizontal offset of the insertion position of the long nozzle relative to the center of the pouring area away from the retaining wall during pouring is 0.2 to 0.6 times the equivalent radius of the pouring area area; the depth of the long nozzle inserted into the molten steel during pouring is 0.05 to 0.3 times the depth of the molten steel in the pouring area. The present invention optimizes the process parameters of tundish pouring, including the pouring position and the immersion depth of the long nozzle. The position of the pouring point determines the flow path of the molten steel into the tundish. Generally, the closer the pouring point is to the center of the pouring area, the more uniform the flow rate will be. If the pouring point is closer to the edge of the tundish, it may cause increased local turbulence, affecting the uniformity of the molten steel. And the appropriate immersion depth can optimize the flow efficiency of the molten steel in the pouring area. Too shallow an immersion depth may cause gas inclusions and cold shuts, while too deep an immersion depth may cause uneven flow of the molten steel, affecting the quality of the ingot.

[0038] In one embodiment of the present invention, the length ratio of the retaining wall to the length between the two ends of the inner wall of the tundish in the long axis direction is 3:10, and the angle between the top surface of the impact zone and the vertical direction is 30°. The cross section of the retaining wall is a combination of two curved surfaces, and the curvature of the retaining wall is 0.35; the blowing component is arranged in the middle and lower part of the retaining wall, the area of ​​the air-permeable brick is 30% of the retaining wall, and the total area of ​​the steel flow hole is 10% of the retaining wall area; the pouring depth d is 100mm, the pouring offset position is 30mm away from the retaining wall, and the molten steel flow rate Q steel is 105000 kg / h, and the gas density ρ is 1.78 kg / m 3 , the dimensionless coefficient α is 32, the dimensionless coefficient k is 1.21, and the total air flow rate Q is 625.28 m 3 / h, the blowing angle θ is 20°.

[0039] Through the above optimization measures, numerical simulation results show that the wall stress of the tundish is reduced by 12.43%, the wall turbulence intensity is reduced by 19.15%, and the life of the tundish is increased by 23.77%.

[0040] The impact zone of the original tundish was flat, and the retaining wall was a U-shaped retaining wall, both of which were vertical surfaces without bending; the total area of ​​the steel flow holes was 8% of the retaining wall area, the pouring depth was 150mm, the pouring position had no offset, the molten steel flow rate was 105,000 kg / h, and there were no blowing components.

[0041] Through the above optimization measures and industrial tests, Figure 3 This is the erosion diagram of the original tundish after 69.16 hours of use. It can be seen that the contact between the retaining wall and the tundish has been completely eroded; Figure 4 This is the erosion diagram of the tundish after 83.3 hours of use using the method of the present invention. It can be seen that some material still remains at the contact between the impact zone slope and the retaining wall and the tundish. The industrial test results show that the life of the tundish is increased by 20.44%.

[0042] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for increasing the service life of a tundish, characterized in that: The steps include: S1. A retaining wall is arranged at the bottom of the tundish in the direction of the molten steel flowing out of the impact zone, and both ends of the retaining wall are connected to the tundish wall to form an enclosed space with the tundish wall at the side of the impact zone. The retaining wall is provided with steel flow holes and a blowing component, and the blowing component is used to blow air into the molten steel in the enclosed space; the cross section of the retaining wall is a combination of at least two curved surfaces, and the curvature of the retaining wall is not greater than 0.8; S2. Control the blowing direction and blowing flow of the blowing parts, and control the position of the long nozzle during pouring to increase the service life of the tundish.

2. The method for increasing the service life of the tundish according to claim 1, characterized in that: In the step S1, the top surface of the impact zone is a slope or an arc surface, and the angle between the top surface of the impact zone and the vertical direction is not less than 15°.

3. The method for increasing the service life of the tundish according to claim 1, characterized in that: In the step S1, the blowing component is arranged at the middle and lower part of the retaining wall; the blowing method is continuous blowing or intermittent blowing; the blowing component is a breathable brick, and the gas blown into the blowing component is an inert gas.

4. The method for increasing the service life of the tundish according to claim 1, characterized in that: In the step S1, the total area of ​​the flow steel holes arranged on the retaining wall does not exceed 30% of the area of ​​the retaining wall; the total area of ​​the blowing components arranged on the retaining wall does not exceed 45% of the area of ​​the retaining wall.

5. The method for increasing the service life of the tundish according to claim 1, characterized in that: In step S1, the length of the retaining wall does not exceed 60% of the length between the two ends of the inner wall of the tundish in the long axis direction.

6. The method for increasing the service life of the tundish according to claim 1, characterized in that: In step S2, the total blowing flow rate Q of the blowing component is: Where Q is the total air flow rate of the air blowing component, ranging from 500 to 2000 m 3 / h;Q steel is the flow rate of molten steel, ranging from 1×10 3 ~2×10 5 kg / h; ρ is the gas density, the gas is an inert gas, and the value range is 0.17~1.8kg / m 3 ; d is the depth of the shroud inserted into the molten steel during pouring, ranging from 10 to 200 mm; Δx is the horizontal offset of the shroud insertion position relative to the center of the pouring area away from the retaining wall during pouring, ranging from 0 to 160 mm; α is a dimensionless coefficient, which is an empirical value and ranges from -0.04 to 7.198×10 6 .

7. The method for increasing the service life of the tundish according to claim 6, characterized in that: In step S2, the angle θ between the blowing direction of the blowing component and the horizontal direction is: Among them, θ is the angle between the blowing direction of the blowing component and the horizontal direction. The direction inclined toward the gravity direction is negative and the range is -60~60°; k is a dimensionless coefficient, which is an empirical value and the range is -3464~3464.

8. The method for increasing the service life of a tundish according to claim 1, characterized in that: In step S2, during pouring, the horizontal offset of the insertion position of the long nozzle relative to the center of the pouring area away from the retaining wall is 0.2-0.6 times the equivalent radius of the pouring area; during pouring, the depth of the long nozzle inserted into the molten steel is 0.05-0.3 times the depth of the molten steel in the pouring area.

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