Composite slag-blocking structure and construction method for reducing casting residue at the end of steel ladle casting.

Abstract

This invention proposes a composite slag-blocking structure and construction method for reducing slag residue at the end of ladle casting. The structure includes a ladle wall and a sloping bottom. The sloping bottom has a stepped area and a slag-blocking area. The nozzle is located in the slag-blocking area. The stepped area has multiple sloping steps with decreasing heights towards the nozzle. The slag-blocking area has a sunken pit concentric with the nozzle. A primary slag-blocking dam and a secondary slag-blocking dam are symmetrically arranged on both sides of the pit. The center of the ladle bottom, the center of the nozzle, and the centers of the primary and secondary slag-blocking dams are located on the same straight line. This invention can change the slag flow trajectory at the end of casting, effectively reduce the critical height of slag falling from the ladle, and partially eliminate vortex slag falling above the nozzle at the end of casting, thereby reducing molten steel residue at the end of ladle casting.

Description

Technical Field

[0001] This application relates to the technical field of steelmaking continuous casting, and more specifically, to a composite slag-blocking structure and construction method for reducing the casting residue at the end of the ladle casting process. Background Technology

[0002] A ladle is a container used in continuous casting to hold molten steel for refining and casting. During continuous steel casting, when slag containing iron oxide, manganese oxide, and silicon oxide flows into the tundish, it causes the loss of easily oxidized alloying elements such as aluminum and titanium in the molten steel, and produces alumina inclusions. This affects the cleanliness of the molten steel and easily leads to surface quality problems in the steel. Furthermore, alumina inclusions in the molten steel can cause nozzle blockage, affecting the flow field in the crystallizer and the number of consecutive heats cast in the tundish. To prevent slag from entering the tundish, some steel mills use electromagnetic induction slag monitoring systems when producing steel grades with very strict cleanliness requirements, such as automotive steel. The consequence is that steel must be retained at the end of the casting process, which, while meeting quality requirements, reduces the yield of molten steel at the end of the casting. Currently, improving the steel yield at the end of the ladle casting process, while ensuring no slag discharge, remains a challenge for many steel plants. Taking measures to weaken or even eliminate converging vortices is key to controlling slag discharge and improving steel yield. Therefore, developing efficient vortex suppression and slag control methods is crucial and urgent for improving steel yield at the end of the casting process.

[0003] Traditional methods for controlling slag runoff from ladles include, for example, "A slag-blocking ball for preventing vortex slag entrainment in ladles" (CN205110763U), which discloses a slag-blocking ball consisting of a solid sphere and a refractory material layer covering the solid sphere. The refractory material layer has two grooves on its surface, the cross-section of which passes through the center of the slag-blocking ball. The diameter of the slag-blocking ball is 170-190mm, effectively eliminating vortex slag entrainment in the ladle. Another patent, "A refractory material for a homogeneous slag-blocking ball for continuous casting ladles and a method for manufacturing the slag-blocking ball" (CN106588005A), discloses a homogeneous slag-blocking ball for ladles, comprising 62-80wt% ZrO2, 14-32wt% Al2O3, 2-6wt% SiO2, 2-4wt% SiC, and 3.0-6.5wt% silica sol, effectively preventing slag from entering the tundish. The invention, "A Method for Controlling Slag Dropping from a Ladle by Blowing Argon Gas Through the Bottom Outlet," (CN104525929A), describes a method that uses an annular permeable brick with a permeability width of 50-300 mm around the bottom outlet of the ladle. During the ladle casting process, when the molten steel level in the ladle is 150-400 mm, the argon blowing pressure is controlled at 0.2-0.7 MPa, allowing argon gas to be blown into the molten steel through the annular permeable brick, thus controlling slag dropping. This invention effectively suppresses slag dropping caused by confluence vortices and drainage pits during ladle casting and can further improve the steel yield.

[0004] In general, current slag control mainly focuses on magnetic field detection, which can only determine the timing of slag discharge but cannot effectively reduce the amount of slag discharged. Therefore, researching and developing more efficient structures for controlling slag discharge at the bottom of the ladle, while reducing casting residue at the end of the casting process and improving steel yield, would have good economic benefits for the production of clean steel. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a composite slag-blocking structure and construction method for reducing the amount of slag remaining at the end of ladle casting, thereby effectively reducing the critical height of slag discharge and improving the slag-steel flow trajectory at the end of the casting process, thus reducing the amount of slag discharged at the end of the casting process and reducing the amount of slag remaining at the end of the casting process.

[0006] The embodiments of this application are implemented as follows:

[0007] This application provides a composite slag-blocking structure for reducing casting residue at the end of ladle casting. The ladle includes a ladle wall and a sloping bottom. The sloping bottom has a stepped area and a slag-blocking area. The nozzle is located in the slag-blocking area. The stepped area has multiple sloping steps with decreasing height towards the nozzle. The slag-blocking area has a sunken pit concentric with the nozzle. A primary slag-blocking dam and a secondary slag-blocking dam are symmetrically arranged on both sides of the pit. The center of the ladle bottom, the center of the nozzle, and the centers of the primary and secondary slag-blocking dams are located on the same straight line.

[0008] In some alternative implementations, the centers of each step of the multi-level inclined staircase are aligned, and the edge of each step includes a middle horizontal line, the two ends of which are provided with inclined lines extending upward to the wall.

[0009] In some optional implementations, the outline of the primary slag barrier includes a first concave arc segment collinear with the circumference of the pit. The two ends of the first concave arc segment are provided with an upwardly inclined first straight line segment. The ends of the first straight line segment are provided with an outwardly convex variable-diameter arc segment. The ends of the variable-diameter arc segment intersect with a second straight line segment. The second straight line segment is collinear with the middle horizontal line of the last step of the multi-step surface.

[0010] In some alternative implementations, the outline of the secondary slag barrier includes a second concave arc segment collinear with the circumference of the pit, the two ends of the second concave arc segment are provided with an upwardly inclined third straight segment, the end of the third straight segment is provided with an outwardly convex arc segment, and the end of the outwardly convex arc segment extends downward to form a fourth straight segment intersecting the wall.

[0011] In some alternative implementations, the angle of inclination of the slanted base is 1° to 5°.

[0012] In some alternative embodiments, the diameter of the pit is 450–700 mm.

[0013] In some optional embodiments, the multi-level inclined steps include a first-level step and a second-level step, the height difference between the first-level step and the second-level step is 50-250mm, and the height difference between the second-level step and the slag-blocking zone is 50-250mm.

[0014] In some optional embodiments, the inclination angle of the diagonal lines of the first and second steps is 110° to 160°, the length of the horizontal line in the middle of the first step is 1500 to 2500 mm, and the length of the diagonal line is 650 to 1200 mm, the length of the horizontal line in the middle of the second step is 1500 to 2500 mm, and the length of the diagonal line is 800 to 1500 mm.

[0015] In some optional embodiments, the height difference between the primary slag barrier and the pit is 250–500 mm, the radius of the variable-diameter arc segment is 25–300 mm, the length of the first straight segment is 500–1000 mm, the height difference between the secondary slag barrier and the pit is 300–700 mm, the length of the third straight segment is 400–700 mm, the radius of the convex arc segment is 200–500 mm, and the length of the fourth straight segment is 10–40 mm.

[0016] A construction method for a composite slag-blocking structure used to reduce casting residue at the end of ladle casting is characterized by the following steps:

[0017] Step a: First, build the bottom of the steel ladle and construct the recess. Then, construct the primary and secondary slag barrier dams at the designed locations.

[0018] Step b: Adjust the tilt angle of the bottom of the ladle by using pad blocks, then use a reverse mold to pour the tilted bottom of the ladle, and finally build the steel ladle wall.

[0019] The beneficial effects of this application are as follows: This application provides a composite slag-blocking structure and construction method for reducing slag residue at the end of steel ladle casting. It sets up a multi-stage stepped inclined bottom and two-stage slag-blocking dams, which can change the flow trajectory of slag residue at the end of casting, effectively reduce the critical height of slag discharge in the ladle, and partially eliminate vortex slag discharge above the nozzle at the end of casting. It can minimize the amount of molten steel at the end of casting when the slag has not reached the height of vortex formation. Both stages of slag-blocking dams are set close to the nozzle, which can play a role in blocking slag at the end of casting. On the other hand, it can increase the eccentricity of the nozzle, thereby reducing the critical height of slag discharge. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an isometric view of an embodiment of this application;

[0022] Figure 2 This is a front view of an embodiment of this application;

[0023] Figure 3 This is a top view of an embodiment of this application;

[0024] Figure 4 This is a diagram showing the distribution of residual slag at the end of the ladle casting process according to an embodiment of this application.

[0025] Figure 5This is a distribution diagram of the flow trajectory of residual slag during the final stage of ladle casting in an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0031] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0033] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0034] like Figure 1 As shown, this invention proposes a composite slag-blocking structure for reducing casting residue at the end of ladle casting. The ladle includes a ladle wall 1 and a sloping bottom 2. The sloping bottom is provided with a stepped area and a slag-blocking area. The nozzle is located in the slag-blocking area. The stepped area is provided with multiple sloping steps with decreasing height towards the nozzle. The slag-blocking area is provided with a sunken pit 3 concentric with the nozzle. A primary slag-blocking dam 4 and a secondary slag-blocking dam 5 are symmetrically provided on both sides of the pit. The center of the ladle bottom, the center of the nozzle, and the centers of the primary and secondary slag-blocking dams are located on the same straight line.

[0035] The centers of each step of the multi-level sloping staircase are aligned. The edge of each step includes a middle horizontal line, and the two ends of the middle horizontal line are provided with sloping lines that extend upward to the wall.

[0036] like Figure 2 , Figure 3 As shown, the multi-level inclined steps include a first-level step 6 and a second-level step 7. The height difference between the first-level step and the second-level step is 50-250mm, and the height difference between the second-level step and the slag-blocking zone is 50-250mm.

[0037] In some alternative implementations, the inclination angle of the diagonal lines of the first and second steps is 110° to 160°, the length of the horizontal line in the middle of the first step is 1500 to 2500 mm, and the length of the diagonal line is 650 to 1200 mm, the length of the horizontal line in the middle of the second step is 1500 to 2500 mm, and the length of the diagonal line is 800 to 1500 mm.

[0038] In some alternative implementations, the outline of the primary slag barrier includes a first concave arc segment 8 that is collinear with the circumference of the pit. The two ends of the first concave arc segment are provided with an upwardly inclined first straight line segment 9. The ends of the first straight line segment are provided with an outwardly convex variable diameter arc segment 10. The ends of the variable diameter arc segment intersect with the second straight line segment 11. The second straight line segment is collinear with the middle horizontal line of the last step of the multi-step surface.

[0039] In some alternative implementations, the outline of the secondary slag barrier includes a second concave arc segment 12 that is collinear with the circumference of the pit. The two ends of the second concave arc segment are provided with an upwardly inclined third straight segment 13. The end of the third straight segment is provided with an outwardly convex arc segment 14. The end of the outwardly convex arc segment extends downward to form a fourth straight segment 15 that intersects with the wall.

[0040] In some alternative implementations, the angle of inclination of the slanted base is 1° to 5°.

[0041] In some alternative implementations, the diameter of the pit is 450–700 mm.

[0042] In some alternative implementations, the height difference between the primary slag barrier and the pit is 250–500 mm, the radius of the variable-diameter arc segment is 25–300 mm, the length of the first straight segment is 500–1000 mm, the height difference between the secondary slag barrier and the pit is 300–700 mm, the length of the third straight segment is 400–700 mm, the radius of the outwardly convex arc segment is 200–500 mm, and the length of the fourth straight segment is 10–40 mm.

[0043] A construction method for a composite slag-blocking structure used to reduce casting residue at the end of ladle casting is characterized by the following steps:

[0044] Step a: First, build the bottom of the steel ladle and construct the recess. Then, construct the primary and secondary slag barrier dams at the designed locations.

[0045] Step b: Adjust the tilt angle of the bottom of the ladle by using pad blocks, then use a reverse mold to pour the tilted bottom of the ladle, and finally build the steel ladle wall.

[0046] After implementing this invention, the remaining casting volume at the end of the ladle period can be reduced from about 8 tons to less than 2 tons.

[0047] Example 1

[0048] The implementation process includes the following steps:

[0049] 1) The structure includes a first part that is a stepped, sloping base that is integrally cast or masonry, with a sloping angle of 3°. The sloping direction is the line connecting the center of the ladle and the center of the sprue, and the thickness of the ladle base decreases sequentially towards the sprue.

[0050] 2) A first-level step, a second-level step, and first- and second-level slag-blocking dams are arranged on the bottom of the sloping enclosure. The first-level step and the second-level step are arranged symmetrically, with a height difference of 150 mm between the first-level step and the second-level step, and a height difference of 100 mm between the second-level step and the slag-blocking zone.

[0051] 3) The inclination angle of the diagonal lines of the first and second steps is 140°. The length of the horizontal line in the middle of the first step is 2000mm and the length of the diagonal line is 850mm. The length of the horizontal line in the middle of the second step is 2000mm and the length of the diagonal line is 1150mm.

[0052] 4) The height difference between the primary slag barrier and the pit is 300mm. The variable diameter arc segment includes two arcs with radii of 100mm and 200mm respectively. The length of the first straight segment is 700mm.

[0053] 5) The height difference between the secondary slag barrier and the pit is 500mm, the length of the third straight section is 550mm, the radius of the convex arc section is 300mm, and the length of the fourth straight section is 15mm.

[0054] 6) Further, when constructing the steel ladle structure, first construct the bottom of the ladle and build a pit with a diameter of 500mm. Then, construct the primary and secondary slag barrier dams at the designed locations. Adjust the inclination angle of the bottom of the ladle using pad blocks, then use a reverse mold to pour the inclined bottom of the ladle, and finally construct the steel ladle wall.

[0055] 7) After implementation, the residual slag at the end of the ladle casting process can be reduced from approximately 8 tons to approximately 1.5 tons. The distribution of residual slag at the end of the ladle casting process is shown in [reference needed]. Figure 4 The distribution of the flow trajectory of residual slag at the end of the ladle casting process is shown in the figure. Figure 5 .

Claims

1. A composite slag stopping structure for reducing the ladle pouring tail end slag carryover, characterized by, The ladle includes a ladle wall and an inclined ladle bottom, the inclined ladle bottom is provided with a stepped area and a slag resisting area, a nozzle is arranged in the slag resisting area, the stepped area is provided with a plurality of stepped inclined surfaces with decreasing height towards the nozzle, the slag resisting area is provided with a sunken pit concentric with the nozzle, a first slag resisting dam and a second slag resisting dam are symmetrically arranged on both sides of the pit, and the centers of the ladle bottom, the nozzle and the first and second slag resisting dams are located on the same straight line; An outer contour line of the first slag resisting dam includes a first concave circular arc segment collinear with the circumference of the pit, two ends of the first concave circular arc segment are provided with first straight segments inclined upward, end heads of the first straight segments are provided with variable-diameter convex circular arc segments, end heads of the variable-diameter convex circular arc segments are connected with second straight segments, and the second straight segments are collinear with middle horizontal lines of last stepped inclined surfaces of the plurality of stepped inclined surfaces. An outer contour line of the second slag resisting dam includes a second concave circular arc segment collinear with the circumference of the pit, two ends of the second concave circular arc segment are provided with third straight segments inclined upward, end heads of the third straight segments are provided with convex circular arc segments, and end heads of the convex circular arc segments extend downward to form fourth straight segments intersecting the ladle wall.

2. The composite slag stopping structure for reducing ladle pouring tail end slag carryover according to claim 1, characterized by, Centers of the stepped inclined surfaces are arranged in alignment, each stepped inclined surface includes a middle horizontal line and an inclined line extending upward from both ends of the middle horizontal line to the ladle wall.

3. The composite slag stopping structure for reducing ladle pouring tail end slag carryover according to claim 1 or 2, characterized in that, The inclined angle of the inclined ladle bottom is 1°-5°.

4. The composite slag stopping structure for reducing ladle pouring tail end slag carryover according to claim 3, characterized by, The diameter of the pit is 450-700 mm.

5. The composite slag stopping structure for reducing ladle pouring tail end slag carryover according to claim 2, characterized by, The plurality of stepped inclined surfaces includes a first stepped inclined surface and a second stepped inclined surface, a height difference between the first stepped inclined surface and the second stepped inclined surface is 50-250 mm, and a height difference between the second stepped inclined surface and the slag resisting area is 50-250 mm.

6. The composite slag stopping structure for reducing ladle pouring tail end slag carryover according to claim 5, characterized by, The inclined angle of the inclined line of the first stepped inclined surface and the second stepped inclined surface is 110°-160°, the length of the middle horizontal line of the first stepped inclined surface is 1500-2500 mm, and the length of the inclined line is 650-1200 mm, the length of the middle horizontal line of the second stepped inclined surface is 1500-2500 mm, and the length of the inclined line is 800-1500 mm.

7. The composite slag stopping structure for reducing ladle pouring tail end slag carryover according to claim 6, characterized by, The height difference between the first slag resisting dam and the pit is 250-500 mm, the radius of the variable-diameter convex circular arc segment is 25-300 mm, the length of the first straight segment is 500-1000 mm, the height difference between the second slag resisting dam and the pit is 300-700 mm, the length of the third straight segment is 400-700 mm, the radius of the convex circular arc segment is 200-500 mm, and the length of the fourth straight segment is 10-40 mm.

8. The construction method for the composite slag stopping structure for reducing the ladle pouring tail end slag carryover according to claim 7, characterized in that, The method includes the following steps: Step a: first, laying the ladle bottom, laying the pit, and laying the first and second slag resisting dams at designed positions; Step b: adjusting the inclined angle of the ladle bottom by using a cushion block, pouring the inclined ladle bottom by using a reverse mold, and finally laying the ladle wall.

Images