A device for improving the yield rate and output of medium and thick plates

Abstract

This invention discloses a device that improves the yield and output of medium and heavy plates. The device includes a support frame, a ladle at the top of the support frame, an intermediate ladle connected to the bottom of the ladle, a continuous casting machine below the intermediate ladle, a water-cooled crystallizer connected to the bottom of the intermediate ladle, and an arc-shaped mounting frame at the bottom of the water-cooled crystallizer. Multiple support rollers are evenly rotatably mounted on the bottom of the arc-shaped mounting frame. Above each support roller, a set of three-section roller mechanisms is arranged on the arc-shaped mounting frame. Each three-section roller mechanism includes two symmetrically arranged end pressure rollers rotatably connected to the side plates of the arc-shaped mounting frame, and a middle pressure roller located between the two end pressure rollers. This invention can effectively improve production efficiency, reduce equipment costs, decrease the occurrence of billet center segregation and cracks, and improve the solidification quality of the cast billet and the overall performance of the steel plate.

Description

Technical Field

[0001] This invention relates to the fields of steelmaking and rolling, and more particularly to an apparatus that facilitates the improvement of yield and output of medium and heavy plates. Background Technology

[0002] Steel rolling yield is a crucial factor influencing the metallurgical costs of steel enterprises, accounting for approximately 85% to 90% of steel rolling production costs. Improving steel production yield not only brings significant economic benefits to the enterprises themselves but also offers numerous advantages to steel users, as it can increase the overall utilization rate of metals in society. The process from billet to finished steel reflects the technological level of steelmaking and rolling mills, and the yield directly impacts production costs; improving the yield means reducing costs and increasing efficiency.

[0003] From the perspective of plastic forming mechanics principles and deformation degree of freedom theory, a slab with a planar cross-section will develop a tongue-like shape after rolling, especially in the production of medium and heavy plates where the ends need to be trimmed, which greatly affects the yield. To solve this problem, the MAS rolling method is currently mainly used for the production of medium and heavy plates. Its principle is to roll the intermediate slab into a concave shape in the widening pass to increase the edge length, thereby turning the tail of the medium and heavy plate into a dovetail shape and improving the yield.

[0004] The MAS rolling method requires variable compression during the widening pass, followed by a 90° rotation before rolling to obtain a steel plate with a high degree of rectangularity. This method is not only time-consuming but also places high demands on the rolling mill.

[0005] Another drawback of MAS rolling is that it requires a transverse rolling process. Therefore, MAS rolling cannot be used when the rolling method is entirely longitudinal or does not require transverse rolling for widening. Full longitudinal rolling is undoubtedly an effective method to increase output in medium and heavy plate workshops. Summary of the Invention

[0006] The purpose of this invention is to provide an apparatus and production method that improves the yield and output of medium and heavy plates, thereby solving the technical problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] This invention discloses a device for improving the yield and output of medium and heavy plates, comprising a support frame, a ladle at the upper part of the support frame, an tundish connected to the bottom of the ladle, a continuous casting machine below the tundish, a water-cooled crystallizer of the continuous casting machine connected to the bottom of the tundish, an arc-shaped mounting frame at the lower part of the continuous casting machine and multiple support rollers evenly rotatably mounted at the bottom of the arc-shaped mounting frame, and a set of three-section roller mechanisms above each support roller on the arc-shaped mounting frame, each three-section roller mechanism including... Two symmetrically arranged end pressure rollers, each rotatably connected to the side plate of the arc-shaped mounting frame, and a middle pressure roller located between the two end pressure rollers; the middle pressure rollers of multiple sets of three-section roller mechanisms sequentially and proportionally press down to a certain height; a drive mechanism for adjusting the pressing height of the middle pressure rollers is provided between the arc-shaped mounting frame and each of the three-section roller mechanisms; a compressed air purging mechanism is provided below each of the three-section roller mechanisms on the arc-shaped mounting frame; a horizontal receiving roller table is provided at the lower outlet of the continuous casting machine; a heating furnace, a descaling box, and a rolling mill are sequentially arranged on the receiving roller table.

[0009] Furthermore, the number of support rollers and three-section roller mechanism on the arc-shaped mounting frame is specifically set to 7.

[0010] Furthermore, the middle pressure rollers of the multiple sets of the three-section roller mechanism press down sequentially at equal heights of 0.2-0.5mm.

[0011] Furthermore, each of the driving mechanisms includes a telescopic rod and a roller frame. The main body of the telescopic rod is connected to the top plate of the arc-shaped mounting frame. The roller frame has an inverted U-shaped cross-section and its upper part is fixedly connected to the telescopic end of the telescopic rod. Each of the middle pressure rollers is rotatably disposed at the lower end of each of the roller frames.

[0012] Furthermore, each of the compressed air purging mechanisms includes an air blowing pipe disposed on the arc-shaped mounting frame and located below the corresponding three-section roller mechanism. One end of each air blowing pipe extends to the outside of the arc-shaped mounting frame and is connected to a compressed air supply pipe. A compressed air nozzle is provided at the bottom of the portion of the air blowing pipe located inside the arc-shaped mounting frame.

[0013] Furthermore, the dephosphorization box includes a box body disposed on the receiving roller conveyor, and a dephosphorization liquid supply pipe is disposed inside the box body. One end of the dephosphorization liquid supply pipe extends to the outside of the box body and is connected to the dephosphorization liquid storage tank. Multiple outlet pipes are evenly spaced at the part of the dephosphorization liquid supply pipe located inside the box body, and a high-pressure dephosphorization nozzle is disposed at the lower end of each outlet pipe.

[0014] Furthermore, the upper end of each of the outlet pipes is connected to the phosphorus removal liquid supply pipe via a universal joint, and the multiple outlet pipes are arranged to gradually slope outward from the middle to both ends.

[0015] Furthermore, this invention also discloses a production method that improves the yield and output of medium and heavy plates, using the apparatus described in claims 1-7, which includes the following steps:

[0016] Step 1: After adjusting the height of the middle pressure roller of the three-roll mechanism of the continuous casting machine, the molten steel is continuously cast into a steel billet with a groove in the middle pressing position through the continuous casting machine. During this process, compressed air is used to blow the surface of the steel billet.

[0017] Step 2: Use a four-stage heating furnace to heat the steel billet, and the temperature of the last two stages of heating should not exceed 1230℃;

[0018] Step 3: Remove phosphorus using a phosphorus removal box;

[0019] Step 4: The steel billet is rolled by a rolling mill. During the rolling process, the reduction in the first pass should not exceed 30mm. After the first pass is completed, the conventional process is followed.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0021] This invention not only achieves the same rolling effect as MAS rolling, but also improves production efficiency, reduces equipment costs, reduces the occurrence of billet center segregation and cracks, and improves the solidification quality of cast billets and the overall performance of steel plates. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings.

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 This is a cross-sectional schematic diagram of the arc-shaped mounting bracket;

[0025] Figure 3 This is a schematic cross-sectional view of the phosphorus removal box;

[0026] Explanation of reference numerals in the attached drawings: 1. Support frame; 2. Ladle; 3. Tundish; 4. Continuous casting machine; 5. Water-cooled crystallizer; 6. Arc-shaped mounting frame; 7. Support roller; 8. End pressure roller; 9. Middle pressure roller; 10. Telescopic rod; 11. Roller frame; 12. Air blowing pipe; 13. Compressed air nozzle; 14. Receiving roller conveyor; 15. Heating furnace; 16. Descaling box; 17. Box body; 18. Descaling solution supply pipe; 19. Descaling solution storage tank; 20. Discharge pipe; 21. High-pressure descaling nozzle; 22. Universal joint; 23. Rolling mill; 24. Steel billet. Detailed Implementation

[0027] like Figures 1-3 As shown, an apparatus for improving the yield and output of medium and heavy plates includes a support frame 1. A ladle 2 is mounted on the upper part of the support frame 1, and an intermediate ladle 3 is disposed at the bottom of the ladle 2 and communicates with it. A continuous casting machine 4 is mounted on the support frame 1 below the intermediate ladle 3, and a water-cooled crystallizer 5 of the continuous casting machine 4 is communicated with the bottom of the intermediate ladle 3.

[0028] The continuous casting machine 1 has an arc-shaped mounting frame 6 fixedly installed at the lower part of the water-cooled crystallizer 5. Multiple support rollers 7 are evenly rotatably mounted on the bottom of the arc-shaped mounting frame 6. Above each support roller 7, a set of three-section roller mechanisms is respectively arranged on the arc-shaped mounting frame 6. In this embodiment, the number of support rollers 7 and three-section roller mechanisms on the arc-shaped mounting frame 6 is specifically set to 7.

[0029] Each of the three-section roller mechanisms includes two symmetrically arranged end pressure rollers 8 that are rotatably connected to the side plates of the arc-shaped mounting frame 6, and a middle pressure roller 9 located between the two end pressure rollers 8. The middle pressure rollers 9 of the multiple sets of three-section roller mechanisms press down at a certain height in sequence and proportionally. Specifically, in this embodiment, the middle pressure rollers of the multiple sets of three-section roller mechanisms press down at a height of 0.2-0.5mm in sequence and proportionally, so the total pressing down in a single sector section of the continuous casting machine is 1.4mm-3.5mm.

[0030] A drive mechanism for adjusting the pressing height of the central pressure rollers 9 is provided between the arc-shaped mounting frame 6 and each of the central pressure rollers 9. Specifically, each drive mechanism includes a telescopic rod 10 and a roller frame 11. The main body of the telescopic rod 10 is connected to the top plate of the arc-shaped mounting frame 6, and the roller frame 11 has an inverted U-shaped cross-section, with its upper part fixedly connected to the telescopic end of the telescopic rod 10. Each of the central pressure rollers 9 is rotatably mounted on the lower end of each of the roller frames 11.

[0031] The arc-shaped mounting frame 6 is provided with a compressed air purging mechanism below each of the three-section roller mechanisms. Each compressed air purging mechanism includes an air blowing pipe 12 installed on the arc-shaped mounting frame 6 and located below the corresponding three-section roller mechanism. One end of each air blowing pipe 12 extends to the outside of the arc-shaped mounting frame 6 and is connected to a compressed air supply pipe. A compressed air nozzle 13 is installed at the bottom of the part of the air blowing pipe 12 located inside the arc-shaped mounting frame 6.

[0032] A horizontal receiving roller conveyor 14 is provided at the lower outlet of the continuous casting machine. A heating furnace 15, a descaling box 16 and a rolling mill 23 are arranged sequentially on the receiving roller conveyor 14.

[0033] The present invention improves the dephosphorization box, wherein the dephosphorization box 16 includes a box body 17 disposed on the receiving roller conveyor 14, and a dephosphorization liquid supply pipe 18 is installed inside the box body 17. One end of the dephosphorization liquid supply pipe 18 extends to the outside of the box body 17 and is connected to the dephosphorization liquid storage tank 19. Multiple outlet pipes 20 are evenly spaced on the part of the dephosphorization liquid supply pipe 18 located inside the box body 17, and a high-pressure dephosphorization nozzle 21 is installed at the lower end of each outlet pipe 20.

[0034] In this embodiment, the upper end of each of the liquid outlet pipes 20 is connected to the phosphorus removal liquid supply pipe 18 through a universal joint 22, and the multiple liquid outlet pipes 20 are arranged to gradually tilt outward from the middle to both ends, with the outward tilt angle of the outermost liquid outlet pipe 20 being 15°.

[0035] This invention also discloses a production method that improves the yield and output of medium and heavy plates, using the apparatus described above for improving the yield and output of medium and heavy plates, comprising the following steps:

[0036] Step 1: Adjust the height of the middle pressure roller of the three-section roller mechanism of the continuous casting machine. Each row of rollers will sequentially and proportionally lower the middle pressure roller of the three sections by 0.2-0.5mm. The total downward pressure of a single sector segment is 1.4-3.5mm. Specific values ​​can be adjusted adaptively according to production needs. After adjustment, the molten steel is continuously cast into a billet 24 with a groove in the middle pressure position using the continuous casting machine. During this process, compressed air is used to blow away excess cooling water from the billet through the compressed air blowing mechanism after each roller table, preventing localized cooling of the billet from affecting subsequent pressure reduction and causing cracks.

[0037] Step 2: The steel billet is heated in a four-stage heating furnace. To avoid defects such as cracks caused by angular decarburization, the heating temperature of the last two stages of the four-stage heating furnace should not exceed 1230℃ to avoid high-temperature rapid heating. In addition, for steel grades with high solution treatment temperatures, such as niobium-added steel, the residence time in the soaking zone should be increased (about 15 minutes).

[0038] Step 3: Dephosphorize using a dephosphorization box. The high-pressure dephosphorization nozzles in the dephosphorization box are set outwards in sequence to effectively remove iron oxide scale from the inclined surface of the billet and press in the iron oxide scale.

[0039] Step 4: The steel billet is rolled by a rolling mill. To prevent edge folding, the first pass reduction should not exceed 30mm. After the first pass is completed, the conventional process is followed.

[0040] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A device for improving the yield and output of medium and heavy plates, characterized in that: The system includes a support frame, with a ladle mounted on its upper part. A tundish, connected to the bottom of the ladle, is located on the bottom of the ladle. A continuous casting machine is positioned below the tundish on the support frame. The water-cooled crystallizer of the continuous casting machine is connected to the bottom of the tundish. An arc-shaped mounting frame is positioned below the water-cooled crystallizer on the continuous casting machine. Multiple support rollers are evenly rotatably mounted on the bottom of the arc-shaped mounting frame. Above each support roller, a set of three-section roller mechanisms is mounted on the arc-shaped mounting frame. Each three-section roller mechanism includes two symmetrically arranged rollers connected to the support rollers. The arc-shaped mounting frame has rotatably connected end pressure rollers and a middle pressure roller located between the two end pressure rollers. The middle pressure rollers of the multiple sets of three-section roller mechanisms are pressed down at a certain height in equal proportions. A drive mechanism for adjusting the pressing height of the middle pressure rollers is provided between the arc-shaped mounting frame and each of the three-section roller mechanisms. A compressed air purging mechanism is provided below each of the three-section roller mechanisms on the arc-shaped mounting frame. A horizontal receiving roller table is provided at the lower outlet of the continuous casting machine. A heating furnace, a descaling box and a rolling mill are arranged in sequence on the receiving roller table.

2. The device for improving the yield and output of medium and heavy plates according to claim 1, characterized in that: The number of support rollers and three-section roller mechanism on the arc-shaped mounting frame is specifically set to 7.

3. The device for improving the yield and output of medium and heavy plates according to claim 1, characterized in that: The middle pressure rollers of the multiple sets of the three-section roller mechanism press down sequentially at equal heights of 0.2-0.5mm.

4. The device for improving the yield and output of medium and heavy plates according to claim 1, characterized in that: Each of the driving mechanisms includes a telescopic rod and a roller frame. The main body of the telescopic rod is connected to the top plate of the arc-shaped mounting frame. The roller frame has an inverted U-shaped cross section and its upper part is fixedly connected to the telescopic end of the telescopic rod. Each of the middle pressure rollers is rotatably disposed at the lower end of each of the roller frames.

5. The device for improving the yield and output of medium and heavy plates according to claim 1, characterized in that: Each of the compressed air purging mechanisms includes an air blowing pipe disposed on the arc-shaped mounting frame and located below the corresponding three-section roller mechanism. One end of each air blowing pipe extends to the outside of the arc-shaped mounting frame and is connected to a compressed air supply pipe. A compressed air nozzle is provided at the bottom of the portion of the air blowing pipe located inside the arc-shaped mounting frame.

6. The device for improving the yield and output of medium and heavy plates according to claim 1, characterized in that: The dephosphorization box includes a box body disposed on the receiving roller conveyor. A dephosphorization liquid supply pipe is disposed inside the box body. One end of the dephosphorization liquid supply pipe extends to the outside of the box body and is connected to the dephosphorization liquid storage tank. Multiple outlet pipes are evenly spaced at the part of the dephosphorization liquid supply pipe located inside the box body. A high-pressure dephosphorization nozzle is disposed at the lower end of each outlet pipe.

7. The device for improving the yield and output of medium and heavy plates according to claim 6, characterized in that: The upper end of each of the liquid outlet pipes is connected to the phosphorus removal liquid supply pipe through a universal joint, and the multiple liquid outlet pipes are arranged to gradually slope outward from the middle to both ends.

8. A production method for improving the yield and output of medium and heavy plates, using the apparatus for improving the yield and output of medium and heavy plates as described in any one of claims 1-7, characterized in that: Includes the following steps, Step 1: After adjusting the height of the middle pressure roller of the three-roll mechanism of the continuous casting machine, the molten steel is continuously cast into a steel billet with a groove in the middle pressing position through the continuous casting machine. During this process, compressed air is used to blow the surface of the steel billet. Step 2: Use a four-stage heating furnace to heat the steel billet, and the temperature of the last two stages of heating should not exceed 1230℃; Step 3: Remove phosphorus using a phosphorus removal box; Step 4: The steel billet is rolled by a rolling mill. During the rolling process, the reduction in the first pass should not exceed 30mm. After the first pass is completed, the conventional process is followed.

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