A diversion impact pad

Abstract

The present invention discloses a flow-guiding impact pad, which is specifically applied to a T-type tundish. Its three right-angled or inwardly inclined sidewalls can suppress the turbulence of the incoming molten steel and alleviate the fluctuation of the molten pool liquid level; an outwardly inclined sidewall can play a role in guiding the molten steel / argon gas stream into the T-type tundish with a larger space to allow it to mix and dissipate turbulence, thereby alleviating the scouring and erosion strength of the impact pad, preventing it from being damaged and extending its service life. The molten steel after drainage carries argon bubbles and is dispersed into the tundish molten pool, increasing the action area for the bubbles to collide with inclusions and float up for removal, which is beneficial to the aggregation, growth and removal of inclusions. At the same time, the impact force of the dispersed argon bubbles on the top slag is reduced during the floating process, thereby alleviating the exposure of the molten steel and the formation of "slag eyes" in the tundish, effectively preventing the secondary oxidation of the molten steel, and improving the removal effect of inclusions, thereby improving the cleanliness of the molten steel and the quality of subsequent products.

Description

Technical Field

[0001] The invention belongs to the technical field of continuous casting equipment, and in particular relates to a flow guide impact pad suitable for a T-type tundish. Background Art

[0002] In the industrial production process of continuous casting of molten steel, the tundish is an important container for storing and diverting molten steel, and it also has the functions of purifying and mixing the molten steel. Good tundish operation is an important guarantee for achieving the above functions, otherwise it may affect the smooth production (for example, secondary oxidation of molten steel leads to nozzle blockage) and product quality (for example, molten steel rolls slag and pollutes molten steel). In the internal structure of the entire tundish molten pool, the molten steel flow rate in the injection zone (or impact zone) is the largest and the turbulence intensity is the strongest, which may cause erosion of refractory materials, "slag eyes" formed by exposed slag layer, and secondary oxidation of molten steel, thereby affecting the cleanliness of molten steel and the quality of subsequent continuous casting products. In order to avoid and alleviate this phenomenon, a common practice is to place a turbulence suppressor or impact pad for suppressing turbulence in the injection zone. The principle is to use a refractory structure of a special shape (such as a cup or basin) to withstand the impact of high-speed molten steel and enhance the dissipation of turbulent motion of molten steel, which is similar to the "brake" effect of molten steel flow. For example, patent CN201621469741.5 discloses a hybrid tundish turbulence suppressor, which can prevent splashing from pouring, reduce turbulence caused by pouring impact, reduce emulsification of tundish covering agent, stabilize fluid flow in the tundish, and prolong the residence time of steel flow in the tundish, significantly reducing the possibility of slag rolling, thereby improving the quality of continuous casting products. Patent CN200980155933.5 discloses an impact pad for a T-type tundish, the impact pad includes a base with an impact surface and an outer side wall, the impact pad improves the uniformity of the poured molten steel from different outlets of the T-type tundish and makes the molten steel discharged from different outlets of the tundish reach the same or approximately the same residence time, while also speeding up the transition time of the molten steel when changing tundishes and maintaining the advantages of traditional impact pads (low slag emulsification).

[0003] However, the turbulence suppressors or impact pads that have been disclosed overemphasize the function of suppressing turbulence. This concept often requires refractory materials to have the ability to withstand the scouring and erosion of high-temperature molten steel for a long time, otherwise the worn and damaged refractory materials will become the source of pollution to the molten steel. For example, patent CN201621469685.5 discloses an enhanced tundish turbulence suppressor, which is designed with a plurality of raised or recessed upper edges to enhance the suppression of turbulence, but due to its complex shape and sharp edges, it may be eroded during long-term continuous pouring. Studies have shown that after multiple furnaces of continuous pouring of molten steel for a long time, the structure of the turbulence suppressor itself has undergone relatively serious wear or deformation, and it loses its turbulence suppression effect in the later stage of pouring and introduces large inclusions. In addition, the inflowing molten steel usually carries a certain proportion of argon to achieve the function of protecting pouring. The structure of the turbulence suppressor often leads to the overall upward movement trend and concentrated overflow behavior of argon in the molten steel, thereby forming a "slag eye" near the long water inlet above, which in turn causes problems such as temperature loss and molten steel absorption.

[0004] Based on the above research background considerations, the first solution is to enhance the material quality of the turbulence suppressor or impact pad as much as possible to enhance its anti-scouring and erosion effect. The second solution is to design a reasonable turbulence suppressor or impact pad structure. Summary of the invention

[0005] Purpose of the invention: In order to overcome the defects of the prior art, the present invention provides a guide impact pad, which is suitable for a T-type ladle, can alleviate the excessive scouring of refractory materials by molten steel and avoid the formation of "slag eyes" near the long water nozzle, and at the same time can increase the area for collision and floating removal of bubbles and inclusions, which is beneficial to the aggregation, growth and removal of inclusions.

[0006] Technical solution: A flow guide impact pad described in the present invention is applied to a T-type tundish, comprising a base and side walls extending upward from the base, wherein the base and the side walls together form a cavity with an upper opening, and the horizontal cross-section of the cavity is rectangular or trapezoidal; the inner wall surface of the side wall comprises three slow-flow walls and one flow guide wall, wherein the slow-flow walls extend vertically from bottom to top or gradually incline toward the center of the cavity, and the flow guide walls gradually incline outward away from the center of the cavity from bottom to top; when the flow guide impact pad is installed in the T-type tundish, the flow guide wall is parallel to the extension direction of the wide side of the T-type tundish.

[0007] Specifically, the angle between the slow flow wall and the horizontal plane is 45-90°. At this angle, the effect of suppressing the turbulence of the inflowing molten steel and relieving the fluctuation of the molten pool liquid level is relatively better.

[0008] The angle between the guide wall and the horizontal plane is 100-160°. Within this angle range, the guide effect on the molten steel and argon bubbles is relatively better, and the area of ​​the argon bubbles colliding with inclusions and floating removal is larger.

[0009] The base has a horizontally extending upper surface, which further simplifies the structure, reduces corners, and thus reduces brush erosion. In another embodiment, the upper surface of the base is a concave curved surface, which smoothly transitions with the side wall, and can also reduce corners and reduce brush erosion.

[0010] Furthermore, when the horizontal cross section of the cavity is trapezoidal, the sides of the flow guide wall and the slow flow wall opposite to the flow guide wall respectively intercepted by the horizontal cross section form a set of parallel opposite sides.

[0011] The trapezoid is an isosceles trapezoid, so that the buffer walls on both sides are symmetrically arranged about the middle plane, reducing turbulence caused by irregular shapes and making the flow field of the inflowing molten steel more stable.

[0012] Furthermore, the side of the guide wall surface intercepted by the horizontal section is a trapezoidal bottom. That is to say, the cavity is open to one side of the guide wall surface, which strengthens the guide effect and enhances the mixing and turbulence dissipation effect of the incoming molten steel and the molten steel in other areas.

[0013] Furthermore, the base and the side wall are integrally formed of refractory materials. The structure is integrally formed of refractory materials that can continuously withstand the contact and erosion of molten steel, which can effectively improve the integrity of the structure and further enhance the erosion and erosion resistance effect.

[0014] Beneficial effects: Compared with the prior art, the structure of the flow-guiding impact pad is simple, and the edges and corners are reduced, so the parts directly subjected to scouring and erosion are reduced, and the scouring and erosion are reduced. In addition, a flow-guiding structure is formed to guide the strong turbulence of the molten steel, alleviate its excessive scouring of the refractory material, and effectively improve the scouring and erosion resistance. Its three right-angled or inward-inclined side walls can play a role in suppressing the turbulence of the incoming molten steel and alleviate the fluctuation of the molten pool liquid level. The outward-inclined side walls can play a role in guiding the flow of molten steel / argon gas streams into the T-shaped tundish with a large space, so that it can be mixed and turbulently dissipated, thereby alleviating the scouring and erosion intensity of the impact pad, preventing it from being damaged and extending its service life. After drainage, the molten steel carries argon bubbles and is dispersed into the tundish molten pool, which increases the action area for the bubbles to collide with inclusions and float up and remove, which is conducive to the aggregation, growth and removal of inclusions. At the same time, the impact force of the dispersed argon bubbles on the top slag is reduced during the floating process, thereby alleviating the exposure of the molten steel and the formation of "slag eyes" in the tundish. Therefore, the secondary oxidation of molten steel can be effectively prevented, and the removal effect of inclusions can be improved, thereby improving the cleanliness of molten steel and the quality of subsequent products. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 1 is a schematic diagram showing a state where the flow guide impact pad of Example 1 of the present invention is installed in a T-shaped tundish;

[0016] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure of the middle flow guide impact pad along the AA direction;

[0017] Figure 3 is a schematic diagram of a top view of the flow guide impact pad of Example 2 of the present invention;

[0018] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure of the middle flow guide impact pad along the BB direction. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to the accompanying drawings.

[0020] like Figure 1 As shown, when the flow guide impact pad 1 is installed in the T-shaped tundish 20, its flow guide wall 14 is parallel to the wide side 21 of the T-shaped tundish 20. In other words, the outwardly inclined flow guide wall 14 guides the inflowing molten steel and argon bubbles toward the wide side 21.

[0021] In Example 1, combined Figure 2 As shown, a domestic steel plant installed the diversion impact pad 1 of the present invention in a T-shaped 4-stream tundish (4 outlets) with a capacity of 25t of molten steel. The base 10 of the diversion impact pad 1 is rectangular, and the angle α between the three slow-flow walls 13 and the horizontal upper surface of the base 10 is 90°, extending vertically upward, and the angle β between the diversion wall 14 and the horizontal upper surface of the base 10 is 120°. The base 10 and the side wall 11 are made of aluminum-carbon refractory material in one piece. Physical simulation experiments and actual application production data show that after using the impact pad, the frequency and degree of exposure of the tundish slag layer are reduced, the area of ​​the argon bubble action area in the middle is increased by more than 80% compared with before, and the actual service life of the diversion impact pad is significantly extended.

[0022] In Example 2, another workshop of the steel plant installed the diversion impact pad 1 of the present invention in a T-shaped 6-stream tundish (6 outlets), and the capacity of the tundish was 36 tons of molten steel. The base 10 of the diversion impact pad 1 is trapezoidal, and the angle α between the three slow-flow walls 13 and the horizontal upper surface of the base 10 is 80°, extending vertically upward, and the angle β between the diversion wall 14 and the horizontal upper surface of the base 10 is 135°. The base 10 and the side wall 11 are made of aluminum-carbon refractory material in one piece. Physical simulation experiments and actual application production data show that after using the impact pad, the frequency and degree of exposure of the slag layer in the tundish are reduced, and the area of ​​the argon bubble action area in the middle is increased by more than 100% compared with before. Similarly, the actual service life of the diversion impact pad is significantly extended.

[0023] In other embodiments, the upper surface of the base 10 is not completely horizontal, but is designed with a smooth arc surface, so that the transition with the side wall is as smooth as possible, which can also produce better results. While the actual service life is extended, the area of ​​the argon bubble in the middle is greatly increased, the frequency and degree of exposure of the tundish slag layer are reduced, and the qualified rate of the product is improved.

[0024] Furthermore, a T-type tundish model with a similar principle and a reduced scale was used to test the flow guide impact pad 1 of the present invention. The test showed that when the angle α between the slow flow wall 13 and the horizontal plane was 45-90°, and the angle β between the flow guide wall 14 and the upper surface of the base 10 was 100-160°, the frequency and degree of exposure of the tundish slag layer were reduced, and the area of ​​the action area of ​​the argon bubbles in the middle was greatly increased. In particular, when the horizontal cross-section of the cavity 12 was an isosceles trapezoid, and the side of the flow guide wall 14 intercepted by the horizontal cross-section was the lower bottom of the trapezoid, the area of ​​the action area increased by more than 1.5 times.

Claims

1. A flow guide impact pad, applied to a T-type tundish (20), characterized in that: The invention comprises a base (10) and a side wall (11) extending upward from the base (10), wherein the base (10) and the side wall (11) together enclose a cavity (12) with an upper opening, and the horizontal cross-section of the cavity (12) is rectangular or trapezoidal; the inner wall surface of the side wall (11) comprises three slow-flow wall surfaces (13) and a guide wall surface (14), wherein the slow-flow wall surface (13) extends vertically from bottom to top or gradually tilts toward the center of the cavity (12), and the guide wall surface (14) gradually tilts outward away from the center of the cavity (12) from bottom to top; When the flow-guiding impact pad (1) is installed in the T-shaped tundish (20), the flow-guiding wall surface (14) is parallel to the extension direction of the wide side (21) of the T-shaped tundish (20); The angle between the slow flow wall (13) and the horizontal plane is 45 to 90 degrees; The angle between the guide wall surface (14) and the horizontal plane is 100-160°; The base (10) has an upper surface extending horizontally.

2. The flow guide impact pad according to claim 1, characterized in that: The upper surface of the base (10) is a concave arc surface.

3. The flow guide impact pad according to claim 1, characterized in that: When the horizontal cross section of the cavity (12) is trapezoidal, the side edges of the flow guide wall surface (14) and the slow flow wall surface (13) opposite to the flow guide wall surface (14) respectively intercepted by the horizontal cross section form a set of parallel opposite sides.

4. The flow guide impact pad according to claim 3, characterized in that: The trapezoid is an isosceles trapezoid.

5. The flow guide impact pad according to claim 4, characterized in that: The side of the guide wall surface (14) intercepted by the horizontal cross section is a lower base of a trapezoid.

6. The flow guide impact pad according to claim 1, characterized in that: The base (10) and the side wall (11) are integrally formed using refractory material.

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