A cold material arrangement method for increasing the thickness of the bottom of a slab shell

Abstract

The present application relates to a kind of cold material arrangement method for increasing the thickness of thick slab shell bottom, belong to the technical field of continuous casting production in metallurgical industry.The technical scheme is: control as follows: (1) before continuous casting, the slab dummy bar head (8) is sent to the appropriate position of crystallizer;(2) the gap between dummy bar head (8) and crystallizer wall copper plate is sealed;(3) first, evenly lay dummy bar head (8) with peg (9), then evenly place rectangular corner material (10) along the length direction of outer arc copper plate (1) of crystallizer, evenly place combined corner material (5) along the length direction of inner arc copper plate (7) of crystallizer and along the width direction of two crystallizer narrow face copper plate (4), evenly place cross-arranged corner material (6) at the middle position of dummy bar head (8).The beneficial effects of the present application are: can quickly increase the thickness of bottom shell, reduce the risk of start-up leakage, reduce the potential safety hazard of production.

Description

Technical Field

[0001] This invention relates to a method for arranging cold material to increase the thickness of the bottom shell of a thick slab before casting, belonging to the technical field of continuous casting process production technology in the metallurgical industry. Background Technology

[0002] Before casting begins on a slab continuous casting machine, the dummy bar head needs to be inserted to a suitable position at the bottom of the crystallizer, and the gap between the bar head and the crystallizer wall is sealed using asbestos rope or similar materials. Molten steel is continuously poured into the crystallizer from the tundish. Under the action of the dummy bar head and the cold material, the molten steel fills the dovetail groove of the dummy bar and quickly solidifies into a single unit. The molten steel on the wide surface of the crystallizer is rapidly cooled and solidified into a slab shell of a certain thickness. When the molten steel inside the crystallizer reaches a certain height, the slab shell, now of a certain thickness, is slowly pulled out by the dummy bar into the secondary cooling chamber of the fan-shaped section for further cooling by a straightening machine. After straightening by the straightening machine, a slab is obtained. Then, it is flame-cut to obtain a slab of a fixed length, which enters the rolling process. The dummy bar is then hoisted out for use during the next casting cycle.

[0003] However, during the casting process, the molten steel has a large impact on the dummy bar. If the molten steel cannot be cooled quickly at this time, a billet shell of a certain thickness will not be formed at the bottom before the billet is pulled. The steel and the dovetail groove will not be firmly bonded, which will lead to accidents such as steel leakage at the bottom of the starting point or premature detachment or breakage of the dummy bar, posing a huge production safety hazard.

[0004] Currently, before casting begins, slab continuous casting machines primarily use cold material added to the bottom of the crystallizer and the head of the dummy bar to rapidly reduce the temperature of the molten steel, achieving a cooling and solidification effect. This forms a slab shell of a certain thickness, preventing accidents such as steel leakage at the bottom during startup or premature detachment or breakage of the dummy bar, thus ensuring smooth production.

[0005] Reference 1: Announcement No. CN108339954B, A method for placing cold material to improve the cooling speed and strength of the first billet in continuous casting, which provides a method for placing cold material by using a three-step process of "assembly + filling gaps + placing material" to improve the cooling speed and strength of the first billet in continuous casting.

[0006] The core of this method lies in the use of spiral cold material with a spiral structure, which reduces the impact of molten steel on the blocking material at the ingot head and increases the solidification rate to achieve smooth production. Reference 2: Announcement No. CN103357829B, Structure and method for placing cold material in the cross section of medium and large continuous casting billets.

[0007] Reference 3: Application Publication No. CN115533052A, A three-dimensional distributed sealing method for slab continuous casting chamfering crystallizer.

[0008] References 2 and 3 provide a method for achieving safe and stable pouring by using a variety of materials in a reasonable arrangement. These two methods involve a large amount of cooling material and are relatively complex to implement, which presents certain drawbacks in terms of efficiency for fast-paced production.

[0009] References 1, 2 and 3 all play a positive role in ensuring the safety and stability of the continuous casting process. However, the spiral material used in Reference 1 is generally purchased externally, resulting in higher costs. References 2 and 3 use a wider variety of materials and have more complex material distribution methods.

[0010] Reference 4: Control Measures for Steel Leakage During Slab Continuous Casting (Shandong Metallurgy, 2004). Reference 4 describes the research and application of steel leakage control technology during slab continuous casting. The improvement process involved is to replace the original cooling steel strips with cooling springs.

[0011] The document mentions the original cooling steel strips used. When blocking the ingot, all the steel strips were arranged in an "X" shape. However, the steel strips were not further combined or optimized. Instead, cooling springs were used to be stacked in layers to achieve the purpose of smooth casting.

[0012] Based on the above background, we propose a cold material arrangement method that can increase the thickness of the bottom shell of a thick slab before casting. Summary of the Invention

[0013] This invention provides a cold material arrangement method that can increase the thickness of the bottom shell of the billet before casting of thick slabs, in order to solve the problem that the bottom shell of a certain thickness cannot be formed before the billet is drawn in the actual production process, and the molten steel cannot be firmly bonded to the dovetail groove of the dummy bar, which leads to accidents such as steel leakage at the bottom of the starting point or premature detachment or breakage of the dummy bar, thereby reducing production safety hazards.

[0014] The present invention adopts the following technical solution: A method for arranging cold material to increase the thickness of the bottom shell of a thick slab, comprising assembly, joint sealing, and material placement, controlled according to the following requirements: (1) Assembly: Before continuous casting begins, the slab dummy bar head is fed to the appropriate position in the crystallizer; (2) Sealing the gap: Seal the gap between the ingot rod head and the copper plate of the crystallizer wall; (3) Fabric: First, use pins to evenly lay the ingot rod head, then evenly place rectangular scraps along the length of the outer arc copper plate of the crystallizer, evenly place combined scraps along the length of the inner arc copper plate of the crystallizer and along the width of the two narrow copper plates of the crystallizer, and evenly place cross-arranged scraps in the middle of the ingot rod head.

[0015] The rectangular scraps evenly placed along the length of the outer arc copper plate of the crystallizer are rectangular slab scraps. The combined scraps evenly placed along the length of the inner arc copper plate of the crystallizer and along the width of the two narrow copper plates of the crystallizer are combined scraps formed by vertically welding two rectangular slab scraps. The cross-arranged scraps evenly placed in the middle of the ingot rod head are scraps formed by cross-arranging two rectangular slab scraps together.

[0016] The rectangular scraps, evenly arranged along the length of the copper plate on the outer arc of the crystallizer, are located at the dovetail groove on the outer arc of the ingot guide rod.

[0017] The rectangular scraps on both sides of the dovetail groove on the outer arc of the dummy bar are arranged perpendicularly to the narrow copper plate of the crystallizer, while the rectangular scraps in the middle of the dovetail groove on the outer arc of the dummy bar are arranged parallel to the narrow copper plate of the crystallizer.

[0018] The dimensions of the rectangular slab scrap are 150mm × 30mm × 10mm.

[0019] The joint sealant is made of asbestos rope or fire-resistant fiber.

[0020] The crystallizer is a water-cooled copper tube crystallizer.

[0021] By employing this invention, when molten steel is injected into the crystallizer, this material distribution method can not only significantly increase the contact area between the molten steel and the cold material, reducing the impact force of the molten steel on the ingot head, but also effectively improve the tightness of the dovetail groove between the billet head and the ingot head. While increasing the thickness of the bottom billet shell, it solves the technical problem of steel leakage caused by insufficient bottom billet shell thickness during the casting process of thick slab billets in related technologies. At the same time, by using steel plate scraps as cold material, the cost is also reduced compared to purchasing cold materials such as springs.

[0022] The present invention has the following advantages: it is simple and quick to operate, can rapidly increase the thickness of the bottom billet shell, reduce the risk of steel leakage at the start, and reduce production safety hazards. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the cold material arrangement in this invention; Figure 2 This is a 3D view of the scraps from this assembly; In the figure: 1- Outer arc copper plate of crystallizer, 2- Gap between the dummy bar head and the copper plate of crystallizer wall, 3- Dovetail groove on the outer arc side of the dummy bar, 4- Narrow face copper plate of crystallizer, 5- Combined scrap, 6- Cross-arranged scrap, 7- Inner arc copper plate of crystallizer, 8- Dummy bar head, 9- Pin, 10- Rectangular scrap. Implementation

[0024] The invention will be further described below with reference to the accompanying drawings and examples.

[0025] See attached document Figure 1 , 2 A method for arranging cold material to increase the thickness of the bottom shell of a thick slab, comprising assembly, joint sealing, and material placement, controlled according to the following requirements: (1) Assembly: Before continuous casting begins, the slab dummy bar head 8 is inserted and sent to the appropriate position in the crystallizer; (2) Sealing: Seal the gap between the ingot rod head 8 and the copper plate of the crystallizer wall; (3) Fabric: First, use nails 9 to evenly lay the ingot rod head 8, then evenly place rectangular scraps 10 along the length of the outer arc copper plate 1 of the crystallizer, evenly place combined scraps 5 along the length of the inner arc copper plate 7 of the crystallizer and along the width of the two narrow copper plates 4 of the crystallizer, and evenly place cross-arranged scraps 6 in the middle of the ingot rod head 8.

[0026] In this embodiment, before continuous casting begins, the dummy bar head 8 is first inserted and fed to a suitable position at the bottom of the water-cooled copper tube crystallizer. The gap between the dummy bar head and the crystallizer wall is then sealed with asbestos rope to prevent leakage of molten steel. After sealing, the dummy bar head 8 is evenly laid out using pins 9. Rectangular scraps 10 are evenly placed at the dovetail groove 3 on the outer arc of the dummy bar, with the rectangular scraps 10 on both sides arranged perpendicular to the narrow copper plate 4 of the crystallizer, and the rectangular scraps 10 in the middle arranged parallel to the narrow copper plate 4. Rectangular scraps 6 are placed crosswise in the middle of the dummy bar head. Combined scraps 5 are evenly placed along the length of the inner arc of the dummy bar head, and combined scraps 5 are evenly placed along the width of the two narrow faces of the crystallizer, thus completing the cold material arrangement. Figure 1 As shown.

[0027] The rectangular scrap 10 is a rectangular slab scrap, the combined scrap 5 is a combined scrap formed by vertically welding two rectangular slab scraps, and the cross-arranged scrap 6 is a scrap formed by cross-arranging two rectangular slab scraps together. The dimensions of the rectangular slab scrap are 150mm×30mm×10mm.

[0028] After the cold charge is arranged, molten steel is continuously poured into the crystallizer from the tundish. Under the action of the dummy bar head and the cold charge, the molten steel fills the dovetail groove of the dummy bar and quickly solidifies with it. The molten steel on the wide surface of the crystallizer is rapidly cooled and solidified into a billet shell of a certain thickness. When the molten steel inside the crystallizer reaches a certain height, the billet shell, now of a certain thickness, is slowly pulled out by the dummy bar into the secondary cooling chamber of the fan-shaped section for further cooling under the action of the straightening machine. After being straightened by the straightening machine, a cast billet is obtained. Then, after flame cutting, a billet of a fixed length is obtained and enters the rolling process. The dummy bar is hoisted out and ready for use during the next casting.

[0029] The present invention adopts the above-mentioned technical solution to achieve stable and safe start-up production, avoiding technical problems such as steel leakage, premature detachment of the ingot rod, and breakage caused by insufficient bottom shell thickness during the start-up of thick slabs, ensuring stable and smooth production and avoiding economic losses caused by bottom steel leakage.

Claims

1. A method for arranging cold material to increase the thickness of the bottom shell of a thick slab, characterized in that: This includes assembly, caulking and sealing, and fabric, and should be controlled according to the following requirements: (1) Assembly: Before continuous casting begins, the slab dummy bar head (8) is inserted and sent to the appropriate position in the crystallizer; (2) Sealing: Seal the gap between the ingot rod head (8) and the copper plate of the crystallizer wall; (3) Fabric: First, use pins (9) to evenly lay the ingot rod head (8), then evenly place rectangular scraps (10) along the length of the outer arc copper plate (1) of the crystallizer, evenly place combined scraps (5) along the length of the inner arc copper plate (7) of the crystallizer and along the width of the two narrow copper plates (4) of the crystallizer, and evenly place cross-arranged scraps (6) in the middle of the ingot rod head (8). The rectangular scrap (10) evenly placed along the length of the outer arc copper plate (1) of the crystallizer is a rectangular slab scrap. The combined scrap (5) evenly placed along the length of the inner arc copper plate (7) of the crystallizer and along the width of the two narrow copper plates (4) of the crystallizer is a combined scrap made by vertically welding two rectangular slab scraps. The cross-arranged scrap (6) evenly placed in the middle of the ingot rod head (8) is a scrap made by cross-arranging two rectangular slab scraps together.

2. The cold material arrangement method as described in claim 1, which can increase the thickness of the bottom shell of a thick slab, is characterized in that: The rectangular scrap (10) evenly placed along the length of the copper plate (1) on the outer arc of the crystallizer is located at the dovetail groove (3) on the outer arc of the ingot rod.

3. The cold material arrangement method as described in claim 2, which can increase the thickness of the bottom shell of a thick slab, is characterized in that: The rectangular scraps (10) on both sides of the dovetail groove (3) of the outer arc of the ingot rod are arranged perpendicularly to the narrow copper plate (4) of the crystallizer, and the rectangular scraps (10) in the middle of the dovetail groove (3) of the outer arc of the ingot rod are arranged parallel to the narrow copper plate (4) of the crystallizer.

4. The cold material arrangement method as described in claim 1, which can increase the thickness of the bottom shell of a thick slab, is characterized in that: The dimensions of the rectangular slab scrap are 150mm × 30mm × 10mm.

5. The cold material arrangement method as described in claim 1, which can increase the thickness of the bottom shell of a thick slab, is characterized in that: The joint sealant is made of asbestos rope or fire-resistant fiber.

6. The cold material arrangement method as described in claim 1, which can increase the thickness of the bottom shell of a thick slab, is characterized in that: The crystallizer is a water-cooled copper tube crystallizer.

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