A method for improving the service life of a tundish

Abstract

The present invention relates to the technical field of continuous casting, and specifically to a method for improving the service life of a tundish. By improving the geometric shape of the dam, adding a blowing component in the middle and lower parts of the dam, optimizing the pouring parameters and controlling their correlation, the flow characteristics of the molten steel can be significantly improved, the impact on the dam and the surrounding area can be reduced, thereby prolonging the service life of the tundish, reducing the maintenance cost, and providing strong support for the stability and efficiency of the continuous casting process.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous casting, and specifically provides a method for improving the service life of a tundish. Background Art

[0002] In the modern steel smelting process, continuous casting technology, as a key process, has greatly improved production efficiency and steel quality. However, the service life of the tundish in continuous casting has always been one of the important challenges in the industry. The dam in the tundish usually bears a 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. The traditional research direction fails to fully consider the influence of molten steel flow on the dam and fails to solve the life problems of the dam 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 molten steel on the dam and its surrounding areas, and significantly improves the service life of the tundish and the dam.

[0004] According to one aspect of the present invention, the following technical solutions are provided:

[0005] A method for improving the service life of a tundish includes the following steps:

[0006] S1. A dam is provided at the bottom of the tundish in the outflow direction of the molten steel in the impact zone. Both ends of the dam are connected to the tundish wall, forming an enclosed space with the tundish wall on the side of the impact zone. The dam is provided with a molten steel flow hole and a gas blowing component, and the gas blowing component is used to blow gas into the molten steel in the enclosed space;

[0007] S2. Control the gas blowing direction and gas blowing flow rate of the gas blowing component, and control the position of the long nozzle during pouring to improve the service life of the tundish.

[0008] As a preferred solution of the method for improving the service life of a tundish according to the present invention, in step S1, the cross-section of the dam is a combination of at least two curved surfaces, and the curvature of the dam is not greater than 0.8.

[0009] As a preferred solution of the method for improving the service life of a tundish according to 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°.

[0010] As a preferred embodiment of the method for increasing the service life of the tundish according to the present invention, in the step S1, the blowing component is arranged at the middle and lower part of the dam; the blowing mode is continuous blowing or intermittent blowing; the blowing component is a porous plug, and the gas blown by the blowing component is argon.

[0011] As a preferred embodiment of the method for increasing the service life of the tundish according to the present invention, in the step S1, the total area of the molten steel flow holes arranged on the dam does not exceed 30% of the area of the dam; the total area of the blowing components arranged on the dam does not exceed 45% of the area of the dam.

[0012] As a preferred embodiment of the method for increasing the service life of the tundish according to the present invention, in the step S1, the length of the dam does not exceed 60% of the length between the two ends of the inner wall of the tundish in the long axis direction.

[0013] As a preferred embodiment of the method for increasing the service life of the tundish according to the present invention, in the step S1, the thickness of the upper and middle part of the dam is adjusted to 1.2 - 3 times the thickness of the existing dam.

[0014] As a preferred embodiment of the method for increasing the service life of the tundish according to the present invention, in the step S2, the total blowing flow rate Q of the blowing component is:

[0015]

[0016] where Q is the total blowing flow rate of the blowing component, and the range is 500 - 2000 m 3 / h; Q steel is the molten steel flow rate, and the range is 1×10 3 ~2×10 5 kg / h; ρ is the gas density, and the gas is usually an inert gas such as argon or helium, and the value range is 0.17 - 1.8 kg / m 3 ; d is the depth of the long nozzle inserted into the molten steel during pouring, and the range is 10 - 200 mm; Δx is the horizontal offset of the insertion position of the long nozzle during pouring relative to the center of the pouring area away from the dam, and the range is 0 - 160 mm; α is a dimensionless coefficient, usually an empirical value, and the value range is -0.04 - 7.198×10 6 .

[0017] As a preferred embodiment of the method for increasing the service life of the tundish according to the present invention, in the step S2, the angle θ between the blowing direction of the blowing component and the horizontal direction is:

[0018]

[0019] Wherein, θ is the angle between the blowing direction of the blowing component and the horizontal direction, with the direction inclined towards the gravity direction being negative, and the range is -60 to 60°; k is a dimensionless coefficient, usually an empirical value, and the value range is -3464 to 3464.

[0020] As a preferred embodiment of the method for improving the service life of the tundish according to the present invention, wherein: in the step S2, the horizontal offset of the insertion position of the long nozzle during pouring relative to the center of the pouring area away from the dam is 0.2 to 0.6 times the equivalent radius of the pouring area.

[0021] As a preferred embodiment of the method for improving the service life of the tundish according to the present invention, wherein: in the 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.

[0022] The beneficial effects of the present invention are as follows:

[0023] The present invention provides a method for improving the service life of a tundish. By improving the geometric shape of the dam, adding a blowing component in the middle and lower parts of the dam, optimizing the pouring parameters and controlling their correlations, the flow characteristics of the molten steel can be significantly improved, the impact on the dam and the surrounding area can be reduced, thereby prolonging the service life of the tundish, reducing the maintenance cost, and providing strong support for the stability and efficiency of the continuous casting process. Brief Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0025] Figure 1 It is a top view cross-sectional view of the tundish with a dam installed according to the present invention;

[0026] Figure 2 It is a structural schematic diagram of the dam and the tundish wall on the side of the impact area forming an enclosed space;

[0027] Figure 3 It is an erosion map of the original tundish after using for 69.16 h;

[0028] Figure 4 It is an erosion map of the tundish after using for 83.3 h by adopting the method of the present invention.

[0029] Explanation of the reference numerals in the drawings:

[0030] 1 - Impact zone, 2a - Retaining wall, 2b - Blowing component, 2c - Molten steel hole, 3 - Tundish, 4 - Taphole.

[0031] The realization of the object, functional features and advantages of the present invention will be further described in conjunction with the embodiments with reference to the accompanying drawings. Detailed implementation manners

[0032] The technical solutions in the embodiments will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] The main object of the present invention is to provide a method for improving the service life of a tundish, with the following advantages:

[0034] (1) Optimize the flow design: By finely designing the geometry of the retaining wall, adding breathable 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 and extending the service life of the tundish, ensuring smoother molten steel flow and improving the overall production efficiency.

[0035] (2) Application of blowing technology: Implement the blowing technology in the middle and lower parts of the retaining wall to change the flow characteristics of the 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.

[0036] (3) Coordination among parameters: The coordinated action of the blowing angle, flow rate, pouring depth and position can optimize the molten steel flow, reduce bubbles and defects, and improve the quality of the molten steel. Optimizing these parameters can accelerate the pouring process, improve the production efficiency, extend the service life of the tundish, reduce energy consumption, and ultimately improve the quality of the molten steel and economic benefits.

[0037] (4) Reduce inclusion erosion: The gas effectively removes inclusions in the molten steel during the rising process, reducing the erosion of the inclusions on the retaining wall. 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.

[0038] (5) Improve the design of the turbulence inhibitor: By changing the impact zone of the turbulence inhibitor from a plane to a slope or arc surface, the flow path of the molten steel is optimized. This design significantly reduces turbulence and impact and reduces the damage to the retaining wall.

[0039] (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.

[0040] 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:

[0041] Impact zone 1, retaining wall 2a, blowing part 2b;

[0042] 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;

[0043] 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;

[0044] 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.

[0045] The embodiment of the present invention also provides a method for increasing the service life of a tundish, comprising the following steps:

[0046] 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;

[0047] 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.

[0048] In an embodiment of the present invention, in the 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 optimizing the geometric shape 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 non-uniformity during the flow of molten steel, thereby improving the overall flow characteristics. Traditional retaining walls usually adopt a planar structure, which easily leads to local stress concentration and further aggravates wear. The adoption of the curved surface design can effectively reduce the impact strength of molten steel during the flow process. By changing the planar shape of the retaining wall into a streamlined curved surface, the flow direction of 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 helps to reduce the flow resistance, thereby optimizing the flow efficiency of 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 molten steel to ensure the best stress effect.

[0049] In an embodiment of the present invention, 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°. By changing the original plane into a slope or an arc surface design and designing a multi-segment slope impact zone, the flow path of molten steel is effectively improved, and the intensity of turbulence and impact is reduced. This design can not only reduce local turbulence and impact but also optimize the overall flow state, making the molten steel flow more smoothly when passing through the turbulence inhibitor and effectively reducing the wear of the retaining wall.

[0050] In an embodiment of the present invention, in the step S1, the gas-blowing component is arranged in the middle and lower part of the retaining wall; the gas-blowing method is continuous gas-blowing or intermittent gas-blowing; the gas-blowing component is a porous plug, and the gas blown by the gas-blowing component is argon. A gas-blowing component is added in the middle and lower part of the retaining wall. The function of the gas-blowing component is to promote the flow of molten steel by blowing in argon, thereby reducing the turbulence effect and the impact force. The gas-blowing component can effectively adjust the flow direction and speed of molten steel in the turbulence inhibitor. By adding a gas-blowing component in the middle and lower part of the retaining wall, a more uniform gas flow distribution can be achieved, reducing the dead zone of the flow, thereby improving the overall flow stability of 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 gas, the flow characteristics of molten steel can be effectively changed. Blowing gas can not only reduce the direct impact force of molten steel on the retaining wall but also reduce the wall pressure and the turbulence intensity. At the same time, this gas can carry 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 the wear of the retaining wall material but also improves the purity of molten steel and the quality of the final product.

[0051] In an embodiment of the present invention, in the step S1, the total area of the molten steel holes provided on the dam does not exceed 30% of the area of the dam; the total area of the gas blowing components provided on the dam does not exceed 45% of the area of the dam; the length of the dam 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 reduce production losses caused by size mismatches and improve the overall production efficiency. The total area of the gas blowing components provided on the dam does not exceed 45% of the area of the dam to avoid excessive occupation of the effective space of the tundish; restricting the area of the gas blowing components also helps ensure the structural stability of the dam, avoiding mechanical stress concentration or damage caused by too many gas blowing ports; at the same time, an appropriate area ratio helps ensure the uniform distribution of the gas flow in the tundish, avoiding local overcooling or overheating, thereby improving the temperature and composition uniformity of the molten steel.

[0052] In an embodiment of the present invention, in the step S1, the thickness of the upper-middle part of the dam is adjusted to 1.2 - 3 times the thickness of the existing dam. This design aims to improve the durability and service life of the dam, especially in the case where the slag causes frequent wear on the dam. The thickened dam can effectively resist the impact and wear of the slag, extend the service life and reduce the maintenance frequency. At the same time, the increase in thickness improves the overall stiffness and stability of the dam, enabling it to better withstand the physical stress brought by the movement of the slag. In addition, the thick-wall design delays the fatigue failure of the material, improves the working reliability, thereby optimizing the production efficiency and reducing the downtime for maintenance. Therefore, this thickening measure not only enhances the wear resistance of the dam but also significantly improves the safety and economy of production.

[0053] In an embodiment of the present invention, in the step S2, the total gas blowing flow rate Q of the gas blowing component is:

[0054]

[0055] where Q is the total gas blowing flow rate of the gas blowing component, and the range is 500 - 2000 m 3 / h; Q steel is the molten steel flow rate, and the range is 1×10 3 ~2×10 5 kg / h; ρ is the gas density, and the gas is usually an inert gas such as argon or helium, and the value range is 0.17 - 1.8 kg / m 3 ; d is the depth of the submerged entry nozzle inserted into the molten steel during pouring, and the range is 10 - 200 mm; Δx is the horizontal offset of the position where the submerged entry nozzle is inserted during pouring relative to the center of the pouring zone away from the dam, and the range is 0 - 160 mm; α is a dimensionless coefficient, usually an empirical value, and the value range is -0.04 - 7.198×10 6 .

[0056] In an embodiment of the present invention, in the step S2, the included angle θ between the blowing direction of the blowing component and the horizontal direction is:

[0057]

[0058] where θ is the included angle between the blowing direction of the blowing component and the horizontal direction, the direction inclined towards the gravity direction is negative, and the range is -60 to 60°; k is a dimensionless coefficient, usually an empirical value, and the value range is -3464 to 3464.

[0059] The present invention clarifies the mutual relationship among the blowing angle, the total blowing flow rate in the tundish, the pouring depth, and the pouring position. Their coordinated action is crucial for the flow, temperature distribution, and composition uniformity of the molten steel. The blowing angle determines the gas distribution 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 lead to excessive surface turbulence. The pouring position determines the flow pattern of the molten steel. Central pouring is beneficial to the uniform distribution of the molten steel. The synergistic effect among the four needs to be adjusted according to the actual process. A reasonable blowing angle, flow rate, pouring depth, and pouring position can optimize the flow pattern of the molten steel, maintain good gas distribution and temperature uniformity, and thus improve the smelting efficiency and the quality of the molten steel.

[0060] In an embodiment of the present invention, in the step S2, the horizontal offset of the insertion position of the long nozzle during pouring relative to the center of the pouring area away from the dam is 0.2 to 0.6 times the equivalent radius of the pouring area; the depth of insertion of the long nozzle 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 submerged depth of the long nozzle. The pouring point position determines the flow path of the molten steel flowing 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 close to the edge of the tundish, it may lead to an increase in local turbulence and affect the uniformity of the molten steel. And an appropriate submerged depth can optimize the flow efficiency of the molten steel in the pouring area. Too shallow a submerged depth may lead to gas inclusions and cold shut, while too deep may cause uneven flow of the molten steel and affect the quality of the billet.

[0061] In one embodiment of the present invention, the length ratio of the retaining wall to the length between the two ends in the major axis direction of the tundish inner wall is 3:10, and the included 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 porous plug is 30% of the retaining wall, and the total area of the molten steel flow holes is 10% of the retaining wall area; the pouring depth d is 100 mm, the pouring offset position is 30 mm away from the retaining wall direction, and the molten steel flow rate Q steel is 105000 kg / h, 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 blowing flow rate Q is 625.28 m 3 / h, and the blowing angle θ is 20°.

[0062] Through the above optimization measures, the numerical simulation results show that the stress on the tundish wall is reduced by 12.43%, the wall turbulence intensity is reduced by 19.15%, and the tundish life is increased by 23.77%.

[0063] The original tundish impact zone is a plane, and the retaining wall is a U-shaped retaining wall, both are vertical surfaces without bending; the total area of the molten steel flow holes is 8% of the retaining wall area, the pouring depth is 150 mm, the pouring position has no offset, the molten steel flow rate is 105000 kg / h, and there is no blowing component.

[0064] Through the above optimization measures, through industrial tests, Figure 3 is the erosion map after the original tundish is used for 69.16 h. It can be seen that the contact area between the retaining wall and the tundish has been completely eroded; Figure 4 is the erosion map after the tundish using the method of the present invention is used for 83.3 h. It can be seen that there is still a part of the material remaining on the slope of the impact zone and the contact area between the retaining wall and the tundish. The industrial test results show that the tundish life is increased by 20.44%.

[0065] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made by using the content of the specification of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is 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; The total air flow rate Q of the air 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 ; 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.

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, 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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