A slab processing method for controlling linear defects in the edge of hot-rolled steel sheets

Abstract

This invention relates to the field of steelmaking and rolling production technology, and discloses a slab processing method for controlling linear defects in the rolled edge of hot-rolled plates. The method includes the following steps: molten steel preparation, pre-pouring preparation, ladle pouring, tundish pouring, continuous casting machine startup, normal pouring, solidification and shaping, pouring completion, cooling and shearing, slab loading, heating, and subsequent processing. The tundish body is equipped with upper water inlets; the flow channel wall of the upper water inlets is made of non-porous material, and there are no air cavities inside the main body; a solid stopper rod is installed inside the main shell, located directly above the upper water inlets. By using solid stopper rods, solid upper water inlets, and other refractory materials to prepare a tundish without argon gas injection, and then using the tundish in the corresponding pouring cycle, argon gas blown into the crystallizer during pouring can be eliminated, thereby reducing slab bubble defects and ultimately reducing or even eliminating linear defects in the rolled edge of hot-rolled plates.

Description

Technical Field

[0001] This invention relates to the field of steelmaking and rolling production technology, specifically to a slab processing method for controlling linear defects in the rolled edge of hot-rolled plates. Background Technology

[0002] With the development of the steel industry, customers are demanding increasingly stringent surface quality requirements for high-end hot-rolled coils. Product quality directly impacts the performance of downstream end products and the company's brand image. Surface defects in hot-rolled products are a crucial indicator of steel plate quality, severely affecting subsequent product quality and yield, thereby reducing production efficiency and causing significant economic losses.

[0003] Linear defects at the edge of hot-rolled coils are one of the common surface defects in hot-rolled products. These linear defects are also known as edge cracks, edge linear cracks, and edge black lines. They are usually distributed on the upper and lower surfaces of the coil within a certain range from the edge on one side or both sides. On the product, they appear as thin lines or bands distributed along the rolling direction and are a common problem in the daily inspection of hot-rolled products.

[0004] Existing steel mills almost universally suffer from edge linear defects. To address this issue, most mills have focused on the hot rolling process, improving aspects such as mill rolls, heating techniques, and mill reduction to mitigate these defects. However, this approach has proven ineffective. Furthermore, improvements at the hot rolling level require alterations to the mill configuration, increasing spare parts requirements and labor intensity, thus raising production costs. In addition, both optimizing slab heating methods and adjusting mill reduction represent significant process changes, carrying substantial risks and potentially leading to batch quality incidents.

[0005] Content of this invention

[0006] The technical problem solved by this invention is: how to avoid linear defects in the rolled edge of hot-rolled steel sheets.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A slab processing method for controlling linear defects in the rolled edge of hot-rolled steel sheets includes the following steps:

[0009] Steel preparation: Obtaining molten steel from converters and refining furnaces;

[0010] Preparations before casting include: preparation of ladle and tundish, inspection of crystallizer, inspection of secondary cooling zone, inspection of tension leveler and shearing device, and sealing of priming ingots;

[0011] Ladle pouring: Molten steel in the ladle, which sits on the rotary table, is poured into the tundish through a sliding plate mechanism and a long nozzle.

[0012] Tundish casting: After the molten steel injected into the tundish reaches a certain height, the casting flow is controlled by the cooperation of the tundish stopper and the top nozzle. The casting flow flows into the crystallizer through the immersion nozzle. When the liquid level in the crystallizer is above the side hole of the immersion nozzle, slag / protective slag can be added to prevent secondary oxidation of the molten steel.

[0013] Continuous casting machine startup: Start the straightening machine to initiate the continuous casting process;

[0014] Normal pouring: Pour the molten steel in the tundish at a stable pouring rate;

[0015] Solidification and shaping: In the crystallizer, molten steel begins to solidify after cooling to form a cast billet;

[0016] End of casting: After the molten steel in the tundish is poured at the end of a casting cycle, the top of the crystallizer is sealed and the tail billet is pulled out at a stable casting speed;

[0017] Cooling and shearing: The billet formed in the crystallizer is cooled twice in the fan-shaped section to form a product that meets the requirements. The billet is then sheared by a shearing device and then conveyed to the subsequent process via roller conveyor.

[0018] Slab loading: Continuous casting slabs are transported from the continuous casting workshop into the slab warehouse via slab loading roller conveyor or slab unloading roller conveyor;

[0019] Heating: After the slab is fed into the heating furnace via the feeding roller conveyor, it is loaded into the heating furnace by the loading machine. After being heated to the set temperature, it is lifted out by the tapping machine according to the rolling rhythm requirements and placed on the furnace exit roller conveyor.

[0020] Subsequent processing: After the heated slab exits the furnace, it is conveyed by a conveyor roller conveyor. After being descaled by a high-pressure water descaling device, the slab is sent to a width-fixing press for side pressing and width determination according to the process. Then, it is transported by roller conveyor into the roughing mill and finishing mill for rolling.

[0021] The intermediate tundish includes a main shell, within which a casting chamber is formed, and the upper dimension of the casting chamber is larger than the lower dimension.

[0022] The lower end of the main shell is provided with a water inlet communicating with the casting chamber; the water inlet is provided with a groove at one end inside the casting chamber, the water inlet includes a main body, a flow channel is provided inside the main body, the flow channel wall is made of non-breathable material, and there is no air cavity inside the main body;

[0023] The main housing is provided with a plurality of stopper rods, the position of which is consistent with the position of the water inlet, and the end of the stopper rod located in the casting chamber is provided with a rod head for engaging with the groove.

[0024] In one aspect of the invention, the cross-sectional profile of the casting chamber is trapezoidal.

[0025] In one aspect of the present invention: the main shell of the intermediate tundish may sequentially include a heat insulation layer, a permanent layer and a working layer from the outside to the inside.

[0026] In one embodiment of the present invention: one end of the main body is fixedly connected to the main shell, and the other end is provided with a graphite panel, and the graphite panel and the exterior of the main body are provided with an iron shell.

[0027] In one aspect of the present invention: the upper end of the main housing is provided with a long water inlet communicating with the casting chamber, and the long water inlet is located in the middle of the main housing.

[0028] In one embodiment of the present invention: the axis of the stopper rod is arranged longitudinally, its upper end penetrates the upper wall of the main housing and is located outside the main housing, and its other end is a rod head integrally fixedly connected, the rod head contacting and engaging with the groove of the water inlet.

[0029] In one aspect of the present invention: a slag-blocking dam is provided in the casting chamber, and the slag-blocking dam is fixedly installed at the bottom of the casting chamber and fixedly connected to the main shell.

[0030] In one aspect of the present invention: a slag-blocking weir is provided in the casting chamber between the slag-blocking dam and the water inlet. The two ends of the slag-blocking weir are fixedly connected to the side walls of the main shell, and a notch is formed above and below it.

[0031] In one embodiment of the present invention: a slag baffle is provided in the casting chamber between the slag baffle and the water inlet, and the bottom of the slag baffle is fixedly connected to the bottom wall of the main shell.

[0032] The slab processing method for controlling linear defects in the rolled edge of hot-rolled plates according to the present invention has at least one of the following technical effects:

[0033] The beneficial effects of this invention are:

[0034] (1) The problem of edge linear defects generated during the rolling process of hot-rolled coils has been solved;

[0035] (2) By improving the continuous casting process and using refractory materials such as solid stopper rods and solid top nozzles, not only is the edge quality of the continuous casting slab improved, but it also has the advantages of not changing the existing smelting process, not affecting production, and not increasing production costs.

[0036] (3) For subsequent processes, the existing rolling process can be kept unchanged, without increasing the cost of equipment modification and avoiding the quality risks caused by the adjustment of the rolling process.

[0037] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0038] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0039] Figure 1 This is a process flow diagram of the present invention;

[0040] Figure 2 This is a process flow diagram of the intermediate package of the present invention;

[0041] Figure 3 This is a schematic diagram of the structure of the intermediate package of the present invention;

[0042] Figure 4 This is a schematic diagram of the structure of one end of the present invention where the water inlet and the immersion water inlet are connected;

[0043] Figure 5 This is a schematic cross-sectional view of one embodiment of the water inlet of the present invention;

[0044] Figure 6 This is a cross-sectional structural schematic diagram of another embodiment of the water inlet of the present invention;

[0045] Figure 7 This is the present invention. Figure 4 Schematic diagram of the structure of the middle BB section;

[0046] Figure 8 This is the present invention. Figure 4 Schematic diagram of the CC section;

[0047] Figure 9 This is a schematic diagram of the stopper rod of the present invention.

[0048] The reference numerals in the figure are as follows: 1. Main shell; 2. Insulation layer; 3. Permanent layer; 4. Working layer; 5. Submersible inlet; 6. Inlet; 7. Panel; 8. Iron shell; 9. Air vent; 10. Long inlet; 11. Stopper rod; 12. Slag dam; 13. Slag weir; 14. Slag plate; 15. Flow stabilizer. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limiting this invention.

[0051] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0052] With the development of the steel industry, customers are demanding increasingly stringent surface quality requirements for high-end hot-rolled coils. Product quality directly impacts the performance of downstream end products and the company's brand image. Surface defects in hot-rolled products are a crucial indicator of steel plate quality, severely affecting subsequent product quality and yield, thereby reducing production efficiency and causing significant economic losses.

[0053] Linear defects at the edge of hot-rolled coils are one of the common surface defects in hot-rolled products. These linear defects are also known as edge cracks, edge linear cracks, and edge black lines. They are usually distributed on the upper and lower surfaces of the coil within a certain range from the edge on one side or both sides. On the product, they appear as thin lines or bands distributed along the rolling direction and are a common problem in the daily inspection of hot-rolled products.

[0054] Existing steel mills almost universally suffer from edge linear defects. To address this issue, most mills have focused on the hot rolling process, improving aspects such as mill rolls, heating techniques, and mill reduction to mitigate these defects. However, this approach has proven ineffective. Furthermore, improvements at the hot rolling level require alterations to the mill configuration, increasing spare parts requirements and labor intensity, thus raising production costs. In addition, both optimizing slab heating methods and adjusting mill reduction represent significant process changes, carrying substantial risks and potentially leading to batch quality incidents.

[0055] The applicant's research revealed that linear defects at the edge of hot-rolled slab coils are primarily caused by porosity defects on the narrow face of the slab. During casting, to prevent the molten steel inflow channel from being blocked by molten steel nodules and to promote heat transfer within the crystallizer, argon blowing is typically used through the stopper rod and the top nozzle. Therefore, the top nozzle usually has an air inlet with an internal air chamber. The top nozzle is made of a breathable material, allowing argon gas to be blown into the air chamber through the air inlet and then permeate into the molten steel (the head of the solid stopper rod engages with a groove at the top of the top nozzle; controlling the gap between them controls the molten steel flow rate, thus controlling the flow of molten steel into the crystallizer). This easily leads to porosity defects on the narrow face of the slab. Therefore, to address the edge linear defects in hot-rolled coils, the applicant started with the steelmaking process, improving the continuous casting process of the slab by using solid stoppers and solid top nozzles, thus preventing argon gas from being blown in during the molten steel pouring process. This reduces or eliminates the need for argon gas injection, preventing blown-in gases, gases from the gas chamber, or other gases from entering the molten steel in the tundish through the permeable top nozzle. This effectively avoids porosity defects on the narrow face of the slab, improving the edge quality of the continuously cast slab and eliminating edge linear defects in hot-rolled coils during subsequent processing. It also has the advantages of not altering the existing smelting process, not impacting production, and not increasing production costs. For subsequent processes, the existing rolling process remains unchanged, avoiding increased equipment modification costs and the quality risks associated with adjusting the rolling process.

[0056] Please see Figure 1-9 This invention relates to a slab processing method for controlling linear defects in the rolled edge of hot-rolled steel sheets, comprising the following steps:

[0057] Steel preparation: The molten steel coming out of the converter and refining furnace has a suitable temperature and composition, and the content of inclusions is minimized to maintain the cleanliness and good castability of the molten steel.

[0058] Preparations before casting mainly include the preparation of the ladle, the preparation of the tundish, the inspection of the crystallizer, the inspection of the secondary cooling zone, the inspection of the straightening machine and shearing device, and the sealing of the ingot, etc.

[0059] Ladle pouring: Molten steel in the ladle, which sits on the rotary table, is poured into the tundish through the sliding plate mechanism and the long nozzle 10. When the liquid level in the tundish reaches the predetermined height, a covering agent can be added to the tundish to prevent secondary oxidation of the molten steel.

[0060] Tundish casting: After the molten steel injected into the tundish reaches a certain height, the casting flow is controlled by the cooperation of the tundish stopper 11 and the upper nozzle 6. The casting flow flows into the crystallizer through the immersion nozzle. When the liquid level in the crystallizer exceeds the side hole of the immersion nozzle, slag / protective slag can be added to prevent secondary oxidation of the molten steel.

[0061] Continuous casting machine startup: Starting the straightening machine is equivalent to starting continuous casting. The initial casting speed is generally 0.2 m / min, maintained for about 60 seconds. The speed can be increased to the set speed according to the production rhythm and the condition inside the crystallizer. During this process, it is necessary to control the pouring speed and pouring time to ensure that the molten steel is injected into the crystallizer evenly.

[0062] Normal pouring: The molten steel in the tundish is poured at a stable pouring rate. In the crystallizer, the inner wall is coated with a layer to reduce wear between the crystallizer and the billet, and to promote heat transfer and cooling of the billet shell within the crystallizer, allowing the molten steel to gradually solidify. During this process, constant attention must be paid to the protective pouring in the tundish and crystallizer, as well as monitoring the operation of each piece of equipment and changes in its parameters.

[0063] Solidification and Shaping: In the crystallizer, molten steel begins to solidify and form a billet after cooling. This process requires careful control of the crystallizer's cooling temperature and rate to ensure that the billet's microstructure and dimensions meet design requirements during solidification.

[0064] Multi-furnace continuous casting: After switching to normal casting, multi-furnace continuous casting operation is still required, including changing the ladle and quick changing the tundish.

[0065] End of casting: After the molten steel in the tundish is poured at the end of a casting cycle, the top of the crystallizer is sealed and the tail billet is pulled out at a stable casting speed.

[0066] Cooling and shearing: The billet formed in the crystallizer undergoes secondary cooling in the fan-shaped section to form a product that meets the requirements. The billet is then sheared by a shearing device and conveyed to the subsequent process via roller conveyor.

[0067] Slab loading: Continuous casting slabs are transported from the continuous casting workshop to the slab warehouse via slab loading roller conveyor or slab unloading roller conveyor. Before the slab reaches the entry point, the relevant technical data of the slab has been sent from the computer system of the continuous casting workshop to the computer system of the hot rolling mill, and the relevant data of the slab is displayed on the monitor so that the staff can check and accept the defect-free qualified slabs.

[0068] Heating: After the slab is fed into the heating furnace via the feeding roller conveyor, it is loaded into the heating furnace by the loading machine. After being heated to the set temperature, it is lifted out by the steel tapping machine according to the rolling rhythm requirements and placed on the heating furnace exit roller conveyor.

[0069] Subsequent processing: After the heated slab exits the furnace, it is conveyed by a conveyor roller conveyor. After being descaled by a high-pressure water descaling device, the slab is sent to a width-fixing press for side pressing and width fixing as needed. Then, it is transported by roller conveyor into the roughing mill and finishing mill for rolling.

[0070] Please see Figure 2-9 In one embodiment of the present invention, the tundish construction process and requirements in this method are as follows: The tundish is constructed in the tundish maintenance area of ​​continuous casting. The tundish includes a main shell 1, within which a casting chamber is formed. The cross-sectional profile of the casting chamber is trapezoidal, and the upper dimension of the casting chamber is larger than the lower dimension. The main shell 1 of the tundish may sequentially include a heat insulation layer 2, a permanent layer 3, and a working layer 4 from the outside to the inside.

[0071] Multiple water inlets 6, communicating with the casting chamber, are respectively provided on both sides of the lower end of the main shell 1. The upper end of each water inlet 6 has a groove for engaging with the head of a solid stopper rod 11. The upper end of each water inlet can communicate with the casting chamber inside the main shell 1. The lower end of each water inlet 6 is connected to a submerged entry nozzle 5. The submerged entry nozzle 5 is used in the continuous casting process, located between the tundish and the crystallizer. It serves as a guide pipe for the flow of molten steel from the tundish to the crystallizer, and its functions are: preventing secondary oxidation of the molten steel, controlling the flow state and injection speed of the molten steel, promoting the flotation of inclusions, and preventing non-metallic inclusions in the protective slag. The structure of the water inlet 6 is as follows: Figure 4-8 As shown, the inlet 6 includes a main body with a flow channel inside. The flow channel wall is made of a non-porous material, and there is no air cavity inside the main body. The upper end of the main body is fixedly connected to the main shell 1, and a graphite panel 7 is provided at its lower end. An iron shell 8 is provided on the outside of the graphite panel 7 and the main body. The specific shape of the iron shell 8 can be designed according to actual needs, such as... Figure 5 , 6 These are two example structures of the iron shell 8. The main body can have vents 9, and each vent 9 can contain a gas channel communicating with the gas cavity inside the upper nozzle 6. A switch structure is provided outside the gas channel to control the flow of gas, allowing gas to be blown in through the vent 9 when needed. The vent 9 can be used to blow in argon, etc. By making the main body of the upper nozzle 6 a solid, airtight structure, argon is prevented from being blown in through the upper nozzle 6 during steel pouring. This reduces the amount of argon flowing into the crystallizer during pouring. Ultimately, the specific structural design of the upper nozzle 6 reduces or even prevents argon bubbles from being captured by the nascent billet shell when solidifying in the crystallizer, thus preventing bubble defects at the edges of the slab.

[0072] The upper end of the main shell 1 is provided with a long sprue 10 communicating with the casting chamber, and the long sprue 10 can be located in the middle of the main shell 1. The long sprue 10 is a heat-resistant material channel connecting the ladle and the tundish, and is closely related to the protective casting effect of the tundish, specifically including preventing secondary oxidation and contamination from air / slag / refractory / drainage sand during steady-state and unsteady-state casting processes. Multiple airtight solid stopper rods 11 are provided inside the main shell 1, each stopper rod 11 located above a corresponding upper sprue 6. The axis of the stopper rods 11 is arranged vertically, and the multiple stopper rods 11 are distributed laterally. The upper end of the stopper rod 11 penetrates the upper wall of the main shell 1 and is located outside the main shell 1, while the lower end of the rod contacts the upper sprue 6, and the position of the stopper rod 11 is consistent with the position of the upper sprue 6. By setting a solid stopper rod 11, argon gas can be prevented from entering the tundish molten steel and flowing into the crystallizer through the stopper rod 11 during the casting process, thereby reducing the amount of argon gas flowing into the crystallizer and preventing argon gas from being captured by the primary billet shell, thus forming bubble defects at the edges and corners of the slab.

[0073] The casting chamber is sequentially equipped with a slag-blocking dam 12, a slag-blocking weir 13, a slag-blocking plate 14, and an impact plate (flow stabilizer 15). The slag-blocking dam 12 is fixedly installed at the bottom of the casting chamber and is fixedly connected to the main shell 1. The two ends of the slag-blocking weir 13 are fixedly connected to the side walls of the main shell 1, and a notch is formed at the top and bottom of the weir. By setting up the slag-blocking dam 12, the slag-blocking weir 13 and the slag-blocking plate 14, the flow of molten steel in the tundish is controlled, and the inclusions are effectively collided, grown and floated. The lower end of the impact plate (flow stabilizer 15) is fixedly connected to the bottom wall of the main shell 1, and serves to buffer the impact of molten steel flowing into the tundish from the long nozzle 10.

[0074] The working principle of this invention is as follows: Research on bubble defects in continuous casting process reveals that linear defects at the edges of thick hot-rolled coils are caused by porosity defects on the narrow face of the slab. Among various gas sources causing slab porosity defects, the severity of the defects is Ar2 > air > O2 > H2. Argon gas blown into the molten steel is captured by the primary slab shell when it solidifies in the crystallizer, preventing the bubbles from rising in time and forming bubble defects. Therefore, to solve this type of defect, the continuous casting process is improved by using solid stopper rods 11, solid top nozzles 6, and other refractory materials to prepare an tundish without argon gas blowing in. Then, the tundish is used in the corresponding casting, which can eliminate argon gas blown into the crystallizer during the casting process, thereby reducing slab bubble defects and preventing the occurrence of edge linear defects at the location of slab bubble defects in subsequent processing, ultimately achieving the goal of reducing or even eliminating edge linear defects in hot-rolled coils.

[0075] After the slabs are cast, the corresponding slabs are randomly removed from the production line and flame-cleaned to check for porosity defects on the narrow faces. The applicant verified that the number of bubble defects at the edges and corners of the slabs was significantly reduced or eliminated. Finally, by tracking the rolling process of the corresponding casting batches, it was found that the incidence of linear defects at the edges of hot-rolled coils was significantly reduced, and the severity of the defects was lessened compared to before. After adopting this process, the applicant successfully solved the problem of linear defects at the edges of hot-rolled coils. Subsequent processes did not report similar rolling defects. The incidence of linear defects at the edges decreased from 55.15% to 11.61%, and the downgrade rate caused by linear defects at the edges decreased from 1.06% to 0.27%. Furthermore, the continuous casting process is mature and stable, and the slab quality is under control.

[0076] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the scope of the claims.

Claims

1. A slab processing method for controlling linear defects in the rolled edge of hot-rolled steel sheets, characterized in that, Includes the following steps: Steel preparation: Obtaining molten steel from converters and refining furnaces; Preparations before casting include: preparation of ladle and tundish, inspection of crystallizer, inspection of secondary cooling zone, inspection of tension leveler and shearing device, and sealing of priming ingots; Ladle pouring: Molten steel in the ladle, which sits on the rotary table, is poured into the tundish through the sliding plate mechanism and the long nozzle (10); Tundish casting: After the molten steel injected into the tundish reaches a certain height, the casting flow is controlled by the cooperation of the tundish stopper (11) and the top nozzle (6). The casting flow flows into the crystallizer through the intrusion-type bottom nozzle (5). When the liquid level in the crystallizer is above the side hole of the intrusion-type bottom nozzle, the opening slag / protective slag can be added to prevent secondary oxidation of the molten steel. Continuous casting machine startup: Start the straightening machine to initiate the continuous casting process; Normal pouring: Pour the molten steel in the tundish at a stable pouring rate; Solidification and shaping: In the crystallizer, molten steel begins to solidify after cooling to form a cast billet; End of casting: After the molten steel in the tundish is poured at the end of a casting cycle, the top of the crystallizer is sealed and the tail billet is pulled out at a stable casting speed; Cooling and shearing: The billet formed in the crystallizer is cooled twice in the fan-shaped section to form a product that meets the requirements. The billet is then sheared by a shearing device and then conveyed to the subsequent process via roller conveyor. Slab loading: Continuous casting slabs are transported from the continuous casting workshop into the slab warehouse via slab loading roller conveyor or slab unloading roller conveyor; Heating: After the slab is fed into the heating furnace via the feeding roller conveyor, it is loaded into the heating furnace by the loading machine. After being heated to the set temperature, it is lifted out by the tapping machine according to the rolling rhythm requirements and placed on the furnace exit roller conveyor. Subsequent processing: After the heated slab exits the furnace, it is conveyed by a conveyor roller conveyor. After being descaled by a high-pressure water descaling device, the slab is sent to a width-fixing press for side pressing and width determination according to the process. Then, it is transported by roller conveyor into the roughing mill and finishing mill for rolling. The intermediate package includes a main shell (1), and a casting chamber is formed inside the main shell (1), with the upper end of the casting chamber having a larger dimension than the lower end. The main shell (1) has water inlets (6) on both sides of its lower end that communicate with the casting chamber; the water inlet (6) has a groove at one end inside the casting chamber, the water inlet (6) includes a main body, a flow channel is provided inside the main body, the flow channel wall is made of non-breathable material, and there is no air cavity inside the main body; The main housing (1) is provided with a plurality of stopper rods (11), the position of the stopper rods (11) is consistent with the position of the water inlet (6), and the end of the stopper rod (11) located in the casting chamber is provided with a rod head for cooperating with the groove.

2. The slab processing method for controlling linear defects in the rolled edge of hot-rolled plate according to claim 1, characterized in that, The cross-sectional profile of the casting chamber is trapezoidal.

3. The slab processing method for controlling linear defects in the edge of hot-rolled slabs according to claim 1, characterized in that, The main shell (1) of the intermediate package includes, from the outside to the inside, a heat insulation layer (2), a permanent layer (3) and a working layer (4).

4. A slab processing method for controlling linear defects in the rolled edge of hot-rolled slabs according to claim 1, characterized in that, One end of the main body is fixedly connected to the main shell (1), and the other end is provided with a graphite panel (7). The graphite panel (7) and the exterior of the main body are provided with an iron shell (8).

5. A slab processing method for controlling linear defects in the rolled edge of hot-rolled plate according to claim 1, characterized in that, The upper end of the main shell (1) is provided with a long water inlet (10) that communicates with the casting chamber, and the long water inlet (10) is located in the middle of the main shell (1).

6. A slab processing method for controlling linear defects in the rolled edge of hot-rolled plate according to claim 1, characterized in that, The stopper rod (11) is arranged longitudinally along its axis. One end of the rod passes through the upper wall of the main housing (1) and is located outside the main housing (1). The other end of the rod is a rod head that is integrally fixed and connected. The rod head is in contact with the groove of the water inlet (6).

7. A slab processing method for controlling linear defects in the rolled edge of hot-rolled slabs according to claim 1, characterized in that, A slag-blocking dam (12) is provided in the casting chamber. The slag-blocking dam (12) is fixedly installed at the bottom of the casting chamber and fixedly connected to the main shell (1).

8. A slab processing method for controlling linear defects in the rolled edge of hot-rolled plate according to claim 7, characterized in that, A slag weir (13) is provided in the casting chamber between the slag dam (12) and the water inlet (6). The two ends of the slag weir (13) are fixedly connected to the side wall of the main shell (1), and a notch is formed above and below it.

9. A slab processing method for controlling linear defects in the rolled edge of hot-rolled plate according to claim 8, characterized in that, A slag baffle (14) is provided in the casting chamber between the slag baffle (13) and the water inlet (6), and the bottom of the slag baffle (14) is fixedly connected to the bottom wall of the main shell (1).

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