A heating furnace for improving slab heating uniformity and a method for using the same

Abstract

The application belongs to the technical field of steel rolling, and particularly relates to a heating furnace for improving the temperature difference of a slab during heating and a use method thereof. The heating furnace comprises a furnace body, an air guiding device and a partition wall. The furnace body is sequentially provided with a heat recovery section, a preheating section, a heating section and a soaking section along the conveying direction of the slab. The air guiding device is arranged in the heat recovery section and is used for forming a negative pressure in the furnace to enable high-temperature flue gas to flow from the soaking section to the heat recovery section. The partition wall is provided with a plurality of partition walls and is arranged at intervals along the conveying direction of the slab and between adjacent two heating areas. The top of the partition wall is provided with a flow guide opening, and the flow guide opening is located at the middle of the width direction of the partition wall. The flow guide opening is used for guiding the high-temperature flue gas on the lower surface of the middle of the slab to flow in a direction away from the slab and to flow to the heat recovery section through the flow guide opening, so as to reduce the heating temperature of the middle of the slab. The partition wall is arranged, and the flow guide opening is arranged on the partition wall to guide the high-temperature flue gas and reduce the heating temperature of the middle of the slab, so as to improve the problem of a large temperature difference of the same slab during the heating of the slab.

Description

Technical Field

[0001] This application belongs to the technical field of heating furnaces in the metallurgical industry, and particularly relates to a heating furnace for improving the heating difference between slabs and the slab itself, and its method of use. Background Technology

[0002] The walking beam furnace is the core equipment in a hot rolling production line for heating slabs to the rolling temperature. The uniformity of slab heating temperature, especially the temperature difference along the length of the slab, i.e., the "uniformity of temperature within the same slab," is a key factor affecting the quality of hot-rolled strip steel. Excessive uniformity of temperature within the same slab can lead to uneven mechanical properties in the strip, such as a strength in the middle being 30-100 MPa higher than at the beginning and end, and an impact toughness 30-50 J lower. It can also easily cause problems such as dimensional inaccuracies, poor strip shape, and even rolling instability. For special steel grades such as Cu-containing steel and IF steel, excessively high temperatures in the middle of the slab can also cause surface peeling defects, seriously affecting the product qualification rate.

[0003] Existing walking beam furnaces typically have multiple heating sections along the slab conveying direction, with partition walls at the bottom of each section to guide flue gas flow and regulate heat distribution within the furnace. Burners are symmetrically arranged on both sides of the furnace body, generating high-temperature flue gas to heat the slab. The slab is supported by staggered fixed and movable beams. The movable beams move along rectangular trajectories of rising, advancing, descending, and retracting, achieving a walking-beam conveying of the slab. After combustion at each burner section, the flue gas flows along the furnace chamber towards the tail end under the suction force, ultimately exiting through the flue at the tail end. During this process, the partition walls at the bottom of the furnace act as a barrier and guide for the flue gas—the flue gas mainly flows from the space above the partition walls towards the tail end of the furnace.

[0004] However, the existing furnace bottom partition structure has the following defects: due to the opposing combustion of the burners on both sides, the flames and high-temperature flue gas converge and accumulate in the middle of the furnace, forming a local high-temperature zone. Simultaneously, some of the high-temperature flue gas is guided to the lower surface of the slab, directly heating the middle of the slab. These two factors combined result in a significantly higher temperature in the middle of the slab along its length than at the beginning and end, with measured temperature differences within the same slab reaching approximately 50°C. Furthermore, the "shading effect" of the fixed beam also leads to uneven local temperatures within the slab, further exacerbating the temperature difference problem. This temperature unevenness not only causes the aforementioned fluctuations in mechanical properties and rolling instability but also restricts the stable production of high-quality steel grades. Summary of the Invention

[0005] This application provides a heating furnace and its method of use for improving the slab heating uniformity, aiming to solve, to some extent, the problem of excessive uniformity during slab heating.

[0006] In a first aspect, this application provides a heating furnace for improving the temperature difference between slabs during heating, comprising a furnace body, an induced draft device, and partition walls. The furnace body is sequentially arranged with a heat recovery section, a preheating section, a heating section, and a soaking section along the slab conveying direction. The induced draft device is located in the heat recovery section to create a negative pressure inside the furnace, so that high-temperature flue gas flows from the soaking section to the heat recovery section. Multiple partition walls are provided and spaced apart along the slab conveying direction, located between adjacent heating zones. A guide port is provided at the top of each partition wall, and the guide port is located in the middle of the width direction of the partition wall. The guide port is used to guide the high-temperature flue gas on the lower surface of the middle part of the slab to flow away from the slab and flow through the guide port to the heat recovery section, thereby reducing the heating temperature of the middle part of the slab.

[0007] Furthermore, it also includes a support conveyor, which is mounted on the partition wall and spaced apart along the width of the furnace body, for supporting and conveying slabs.

[0008] Furthermore, the supporting conveyor includes staggered fixed beams and movable beams, the fixed beams being used to support the slab, and the movable beams being used to move the slab along the length of the furnace body.

[0009] Furthermore, it also includes a heating assembly, which includes a plurality of heating nozzles spaced apart on the furnace body along the slab conveying direction. The heating nozzles are located on both sides of the preheating section, the heating section and the soaking section, and are arranged symmetrically.

[0010] Furthermore, the heating nozzle includes an upper nozzle disposed in the upper half of the furnace body and a lower nozzle disposed in the lower half of the furnace body.

[0011] Furthermore, the heating section includes a first heating section and a second heating section, wherein the heating power of the heating nozzles of the first heating section and the second heating section is independently controlled to adjust the heating intensity according to the slab temperature.

[0012] Furthermore, the partition wall is 1.1~1.3m high and 0.49~0.51m away from both sides of the furnace wall. The guide port is rectangular, with a width of 0.6-0.8m and an opening height of 0.3-0.5m. The height of the lower edge of the guide port from the furnace bottom matches the height of the centerline of the lower nozzle.

[0013] Furthermore, the induced draft device is an induced draft fan, used to drive the high-temperature flue gas from the heat equalization section to the heat recovery section.

[0014] Secondly, this application provides a method for using a heating furnace to improve the heating difference between slabs. The method of heating slabs using the heating furnace described above includes the following steps: (In the steel rolling industry, heating is generally started only once every few months. After starting, it is in a heating or heat preservation state. In production, slabs are directly fed into the furnace for heating, rather than the heating is started after the slabs are put in). S100, Place the slab to be heated into the heating furnace, and place the slab on the support conveyor; S200, start the induced draft device to create negative pressure in the furnace, so that the high-temperature flue gas flows from the heat soaking section to the heat recovery section; S300, start the heating nozzle, the slab passes through the heat recovery section, preheating section, heating section and soaking section in sequence for heating. The heating section includes a first heating section and a second heating section. The heating power of the first heating section and the second heating section are independently controlled according to the slab temperature. S400 During the heating process, the high-temperature flue gas on the lower surface of the middle part of the slab is guided by the guide port at the top of the partition wall to flow away from the slab and then flows to the heat recovery section through the guide port to reduce the heating temperature of the middle part of the slab. S500: After heating, the slab is sent out from the soaking section.

[0015] Furthermore, in the S300 heating step, when the temperature of the slab in the first heating section is too high, the heating power of the heating nozzle in the second heating section is reduced; when the temperature of the slab in the first heating section is too low, the heating power of the heating nozzle in the second heating section is increased; and the temperature difference along the length of the slab after heating is controlled within 25°C.

[0016] The advantages of this application compared to the prior art are: This application addresses the issue of high-temperature flue gas from the lower surface of the slab's center being guided away from the slab by partition walls with guide openings in these walls. The gas flows through these guide openings into the heat recovery section, reducing the heating temperature in the middle of the slab and thus decreasing the temperature difference between the middle and ends. This improves the problem of excessive temperature variation between the two sides of the slab during heating. In operation, the induced draft fan in the heat recovery section is activated, creating a negative pressure within the furnace. This causes the high-temperature flue gas to flow stably from the homogenization section towards the heat recovery section, establishing a directional flue gas flow. Subsequently, the high-temperature flue gas from the lower surface of the slab's center, as it flows through the partition walls, is guided by a guide opening located in the middle of the top width of the partition wall. This changes the original flow path, redirecting the flue gas away from the slab and allowing it to flow through the guide openings into the heat recovery section. This prevents the high-temperature flue gas from directly impacting the lower surface of the slab's center.

[0017] By setting guide ports on the partition wall, the temperature difference between the slab and the sheet was improved. The temperature difference along the length of the slab was reduced from about 50℃ to less than 25℃, significantly improving the uniformity of the slab heating temperature. The improvement in temperature uniformity directly leads to the homogenization of the mechanical properties of the product. The strength difference between the middle and the head and tail of the slab is no more than 30MPa, and the impact toughness difference is no more than 30J, effectively solving the performance fluctuation problem caused by uneven temperature. In addition, the improvement in the temperature difference between the slab and the sheet reduces the rolling force, crown, and dimensional fluctuations during the rolling process, enhances rolling stability, and is conducive to the production of high-precision strip steel products and extends the service life of the equipment. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a heating furnace for improving the heating difference between slabs in an embodiment of this application; Figure 2 This is an internal structural diagram of a heating furnace provided in an embodiment of this application for improving the heating difference between slabs. Attached image description: 100. Furnace body; 101. Heat recovery section; 102. Preheating section; 103. Heating section; 104. Soaking section; 200. Slab; 300. Exhaust fan; 400. Partition wall; 401. Drainage outlet; 500. Supporting conveyor components; 501. Fixed beam; 502. Movable beam; 600. Supporting columns; 700, upper nozzle; 701, lower nozzle. Detailed Implementation

[0021] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0023] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, a~b (i.e., a and b), a~c, b~c, or a~b~c, where a, b, and c can be single or multiple.

[0024] The terms "first" and "second" are used only to describe the purpose and to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the provisions of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0025] The terminology used in the embodiments of this application is for the purpose of describing particular implementations only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the implementations of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0027] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0028] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0029] In a first aspect, this application provides a heating furnace for improving the heating difference between slabs, comprising a furnace body 100, an induced draft device 300, and a partition wall 400. The furnace body 100 is sequentially arranged with a heat recovery section 101, a preheating section 102, a heating section 103, and a soaking section 104 along the conveying direction of the slab 200. The induced draft device 300 is disposed in the heat recovery section 101 to create a negative pressure inside the furnace, so that high-temperature flue gas flows from the soaking section 104 towards the heat recovery section 101. The partition wall... Multiple partition walls 400 are provided and spaced apart along the conveying direction of the slab 200, and located between two adjacent heating zones. A guide port 401 is provided on the top of the partition wall 400, and the guide port 401 is located in the middle of the width direction of the partition wall 400. The guide port 401 is used to guide the high-temperature flue gas on the lower surface of the middle part of the slab 200 to flow away from the slab 200, and flow through the guide port 401 to the heat recovery section 101, so as to reduce the heating temperature of the middle part of the slab 200.

[0030] In this embodiment, the furnace body 100 of the heating furnace has a total length of 59m, and is sequentially arranged with a heat recovery section 101, a preheating section 102, a heating section 103, and a soaking section 104 along the conveying direction of the slab 200. Specifically, the heat recovery section 101 is 26.7m long, the preheating section 102 is 7.8m long, the first heating section 103 is 9.3m long, the second heating section 103 is 6.9m long, and the soaking section 104 is 8.3m long. The furnace body 100 has an overall rectangular structure, is lined with refractory material, has a flat or arched roof, and is paved with refractory bricks at the bottom. A draft fan 300 is provided at the end of the heat recovery section 101. This draft fan 300 can be a draft fan, a flue fan, or other ventilation equipment capable of generating negative pressure. It is used to create negative pressure inside the furnace body 100 or to provide suction for high-temperature flue gas, causing the high-temperature flue gas to move directionally from the heat soaking section 104 towards the heat recovery section 101, providing a power basis for flue gas flow guidance. Partition walls 400 are provided at the furnace bottom between the heat recovery section 101 and the preheating section 102, between the preheating section 102 and the heating section 103, and between the heating section 103 and the heat soaking section 104. The partition walls 400 extend along the width direction of the furnace body 100 and are mainly used to adjust the heat flow distribution inside the furnace. A guide port 401 is provided at the top of the partition wall 400. The guide port 401 is located in the middle of the width direction of the partition wall 400 and has a rectangular structure. In other embodiments, the shape of the guide port 401 is not limited to rectangle; it can also be elliptical or trapezoidal.

[0031] In practice, after the induced draft fan 300 is activated, a negative pressure is created inside the furnace, causing the high-temperature flue gas to flow stably from the soaking section 104 to the heat recovery section 101. When the high-temperature flue gas flows along the furnace to the partition wall 400, some of the high-temperature flue gas that would have directly impacted the lower surface of the middle part of the slab 200 is guided by the guide port 401 located in the middle of the width direction at the top of the partition wall 400. This changes the original flow path, diverting the gas away from the slab 200 and flowing towards the heat recovery section 101 through the guide port 401, thus preventing the high-temperature flue gas from directly impacting the lower surface of the middle part of the slab 200. By establishing directional flue gas flow through the induced draft fan 300, combined with the flue gas diversion effect of the guide port 401 at the top of the partition wall 400, the direct heating of the middle part of the slab 200 by the high-temperature flue gas is effectively avoided, significantly reducing the heating temperature of the middle part of the slab 200. This reduces the temperature difference between the slab and the slab along its length from about 50°C to less than 25°C, demonstrating a significant improvement effect.

[0032] Furthermore, it also includes a support conveyor 500 and a support column 600. The support column 600 is disposed inside the furnace body 100, and the support conveyor 500 is mounted on the support column 600 and spaced apart along the width direction of the furnace body 100, for supporting and conveying the slab 200.

[0033] In this embodiment, the supporting conveyor 500 consists of multiple parallel cylindrical beams. Supporting columns 600 are spaced apart along the width of the furnace body 100. The supporting conveyor 500s are mounted one-to-one on the supporting columns 600, maintaining a certain vertical distance between the supporting conveyor 500 and the partition wall 400. A transverse gap is formed between adjacent supporting conveyor 500s, and a vertical space is formed between the bottom of the supporting conveyor 500 and the furnace bottom. These transverse gaps and vertical spaces together constitute a three-dimensional channel network for flue gas circulation. The supporting conveyor 500 extends continuously along the length of the furnace body 100, with its two ends located on the outer sides of the furnace inlet and outlet, respectively, to facilitate connection with the stepper drive mechanism.

[0034] Specifically, the slab 200 is placed on the supporting conveyor 500, which carries and transports it. Since the supporting conveyor 500 and the partition wall 400 are spaced apart in the height direction, a flue gas flow gap is formed between them. The partition wall 400 not only separates the heating area and guides the flue gas flow, but also serves as the load-bearing foundation for the supporting conveyor 500, allowing the partition wall 400 and the supporting conveyor 500 to function separately and without interference. During the heating process, the high-temperature flue gas guided by the guide port 401 flows smoothly from below the slab 200 towards the heat recovery section 101 through the lateral gaps between the supporting conveyors 500, the vertical space between the bottom of the supporting conveyor 500 and the furnace bottom, and the gap between the supporting conveyor 500 and the partition wall 400, thus moving away from the lower middle surface of the slab 200.

[0035] Furthermore, the supporting conveyor 500 includes staggered fixed beams 501 and movable beams 502. The fixed beams 501 are used to support the slab 200, and the movable beams 502 are used to drive the slab 200 to move along the length of the furnace body 100.

[0036] In this embodiment, the supporting conveying component 500 includes staggered fixed beams 501 and movable beams 502, and the supporting column 600 includes fixed columns and movable columns. The fixed beams 501 are mounted on the furnace bed frame of the furnace body 100 via fixed columns, and the fixed columns are fixedly connected to the furnace bottom, keeping the fixed beams 501 stationary and used to support the plate during the intervals of the stepping cycle. The movable beams 502 are mounted on the stepping frame via movable columns, which are inserted into the furnace through holes in the furnace bed, with the movable beams 502 mounted on top. The movable columns move with the stepping frame, driving the movable beams 502 to perform rectangular trajectory movements of rising, forward, falling, and backward, realizing the stepping conveying of the slab 200. Both the fixed beams 501 and the movable beams 502 are water-cooled supporting beams, with cooling water circulating inside to prevent deformation or melting under high-temperature conditions and to ensure structural strength.

[0037] Specifically, the positive cycle motion of the movable beam 502 is executed in the following sequence: In the rising phase, the movable beam 502 rises to lift the slab 200 from the fixed beam 501; in the forward phase, the movable beam 502 moves forward one step, carrying the slab 200 forward; in the descending phase, the movable beam 502 descends to place the slab 200 back onto the fixed beam 501; in the reversing phase, the movable beam 502 retreats to its starting position without load. Through these four-step cycle motions, the slab 200 is conveyed in a stepping motion within the furnace. During the conveying process, there is intermittent contact between the slab 200 and the beam, which is beneficial for the uniform heating of the lower surface of the slab 200.

[0038] The staggered arrangement of fixed beams 501 and movable beams 502 in a step-by-step conveying method ensures smooth conveying with minimal impact on the slab 200. Furthermore, the intermittent contact between the slab 200 and the beams during conveying promotes uniform heating of the lower surface of the slab 200. The staggered arrangement of fixed beams 501 and movable beams 502 provides ample space for flue gas to flow beneath the slab 200, forming a complete flue gas diversion system with the guide port 401. The water-cooled structure ensures the structural strength and long-term operational reliability of the supporting conveyor component 500 under high-temperature environments.

[0039] Furthermore, it also includes a heating assembly, which includes a plurality of heating nozzles spaced apart on the furnace body 100 along the conveying direction of the slab 200. The heating nozzles are located on both sides of the preheating section 102, the heating section 103 and the heat soaking section 104 and are arranged symmetrically.

[0040] In this embodiment, the heating nozzles are evenly spaced along the length of the furnace body 100, with each nozzle on one side corresponding to the other, thus reducing the temperature difference in the width direction inside the furnace body 100. The heat supply of each section of the heating nozzles can be independently adjusted to meet the temperature requirements of the slab 200 at different heating stages. In other embodiments, the arrangement density of the heating nozzles can be differentiated according to the heating process requirements of each section. For example, the nozzle arrangement density of the heating section 103 can be greater than that of the preheating section 102 and the soaking section 104.

[0041] After the heating nozzles are ignited, flames are injected into the furnace body 100 to radiate heat onto the slab 200. The nozzles on both sides are symmetrically arranged to ensure uniform temperature distribution across the width of the furnace chamber. Each section of the nozzles is independently controlled, allowing adjustment of the heat supply according to the temperature requirements of the slab 200 in each section. The preheating section 102 slowly raises the temperature of the slab 200 to avoid excessive thermal stress; the heating section 103 rapidly heats the slab 200 to the target temperature; and the soaking section 104 maintains the temperature of the slab 200, ensuring a uniform temperature throughout.

[0042] Furthermore, the heating nozzle includes an upper nozzle 700 disposed on the upper half of the furnace body 100 and a lower nozzle 701 disposed on the lower half of the furnace body 100.

[0043] In this embodiment, the upper nozzle 700 and the lower nozzle 701 are symmetrically arranged on both sides of the furnace body 100. The centerline of the lower nozzle 701 is 0.9~1.1m above the furnace bottom and about 1.1m from the lower surface of the slab 200. The upper nozzle 700 mainly heats the upper surface of the slab 200, while the lower nozzle 701 mainly heats the lower surface of the slab 200. The upper and lower nozzles 701 work simultaneously to symmetrically heat the slab 200 from top to bottom, resulting in a uniform temperature distribution along the thickness of the slab 200. The lower nozzle 701 cooperates with the guide port 401. Some of the flue gas generated by the lower nozzle 701, which would normally directly impact the middle of the lower surface of the slab 200, is diverted under the guidance of the guide port 401, preventing overheating of the middle of the lower surface of the slab 200. The upper and lower nozzles 701 heat the upper and lower surfaces of the slab 200 respectively, resulting in a uniform temperature distribution along the thickness of the slab 200 and preventing warping deformation caused by excessive temperature difference between the upper and lower surfaces of the slab 200. Meanwhile, the lower nozzle 701 works in conjunction with the guide port 401 to divert some of the high-temperature flue gas, preventing overheating in the middle of the lower surface of the slab 200 and further improving the difference in performance between slabs.

[0044] Further, the heating section 103 includes a first heating section 103 and a second heating section 103. The heating power of the heating nozzles in the first heating section 103 and the second heating section 103 is independently controlled to adjust the heating intensity according to the temperature of the slab 200. In this embodiment, the heating power of the heating nozzles in the first heating section 103 and the second heating section 103 is independently controlled to adjust the heating intensity according to the temperature of the slab 200. Specifically, the control system monitors the actual temperature of the slab 200 after passing through the first heating section 103 in real time and compares it with the target temperature. When a temperature deviation from the target value is detected, the control system automatically adjusts the heating power of the second heating section 103 so that the slab 200 reaches the target temperature before entering the soaking section 104. Temperature monitoring can be performed using an infrared thermometer or a thermocouple, and the control method can be PID regulation.

[0045] Furthermore, the partition wall 400 has a height of 1.1-1.3m and a distance of 0.49-0.51m from both sides of the furnace wall. The guide port 401 is rectangular, with a width of 0.6-0.8m and an opening height of 0.3-0.5m. The height of the lower edge of the guide port 401 from the furnace bottom matches the height of the centerline of the lower nozzle 701.

[0046] In this embodiment, the height of the partition wall 400 and its distance from the furnace wall determine the cross-sectional area of ​​the flue gas flow through the upper space of the partition wall 400; the size of the guide port 401 determines the amount of flue gas that is guided and diverted. Through the optimized matching of the above-mentioned dimensional parameters, the amount of flue gas guided by the guide port 401 accounts for 30% to 50% of the total flue gas in the middle of the furnace, which effectively reduces the temperature in the middle of the slab 200 without affecting the overall heating efficiency. The lower edge of the guide port 401 is 0.8-1.0m above the furnace bottom, which matches the height of the lower nozzle 701, ensuring that the high-temperature flue gas flowing towards the middle of the lower surface of the slab 200 can be effectively captured.

[0047] Furthermore, the induced draft device 300 is an induced draft fan, used to drive the high-temperature flue gas from the heat soaking section 104 to the heat recovery section 101. In this embodiment, the induced draft fan serves as the power source for the flue gas flow, making the flue gas flow direction controllable and the flow rate adjustable. This provides a stable flow environment for the guide port 401 to guide the flue gas to a different path, ensuring a stable and reliable guiding effect. Simultaneously, the induced draft fan and the guide port 401 work together to form a complete directional flue gas flow system, effectively reducing the temperature in the middle of the slab 200.

[0048] Secondly, this application provides a method for using a heating furnace to improve the heating uniformity of slabs, wherein the slab 200 is heated using the aforementioned heating furnace, including the following steps: S100, the slab 200 to be heated is placed into the heating furnace, so that the slab 200 is placed on the support conveyor 500; S200, the slab 200 is heated sequentially through the heat recovery section 101, the preheating section 102, the heating section 103 and the heat soaking section 104. The heating section 103 includes a first heating section 103 and a second heating section 103. The heating power of the first heating section 103 and the second heating section 103 is independently controlled according to the temperature of the slab 200. S300 During the heating process, a negative pressure is formed in the furnace by the induced draft device 300, which causes the high-temperature flue gas to flow from the heat homogenization section 104 to the heat recovery section 101. The high-temperature flue gas on the lower surface of the middle part of the slab 200 is guided by the guide port 401 at the top of the partition wall 400 to flow away from the slab 200 and flow to the heat recovery section 101 through the guide port 401 to reduce the heating temperature of the middle part of the slab 200. S400, the slab 200 after heating is completed is sent out from the heat soaking section 104.

[0049] In this embodiment, the specific steps are as follows: First, the slab 200 to be heated is fed into the furnace and placed on the supporting conveyor 500; then, the slab 200 is heated sequentially through the heat recovery section 101, the preheating section 102, the heating section 103, and the heat soaking section 104. The heating section 103 includes a first heating section 103 and a second heating section 103. The heating power of the first heating section 103 and the second heating section 103 is independently controlled according to the temperature of the slab 200. During the heating process, the induced draft device 300 works continuously to form a negative pressure in the furnace, causing the high-temperature flue gas to flow from the heat soaking section 104 to the heat recovery section 101. The high-temperature flue gas on the lower surface of the middle part of the slab 200 is guided away from the slab 200 through the guide port 401 at the top of the partition wall 400 and flows to the heat recovery section 101 through the guide port 401, thereby reducing the heating temperature of the middle part of the slab 200. After heating is completed, the slab 200 is sent out from the heat soaking section 104.

[0050] The induced draft device 300 continuously operates to establish directional flue gas flow, and the guide port 401 precisely guides the high-temperature flue gas on the lower surface of the middle part of the slab 200 to change course, avoiding direct impact of flue gas on the middle part of the slab 200. At the same time, the independent power control of the first heating section 103 and the second heating section 103 dynamically adjusts the heating intensity according to the temperature of the slab 200. The three work together to significantly improve the heating difference between the slab and the slab. The temperature difference along the length of slab 200 was reduced from approximately 50℃ to less than 25℃, achieving a 50% improvement in the uniformity of the same-slab temperature, significantly enhancing the uniformity of the heating temperature of slab 200. This improved temperature uniformity directly leads to more uniform mechanical properties of the product. The strength difference between the middle and the ends of slab 200 is no greater than 30MPa, and the impact toughness difference is no greater than 30J, effectively solving the performance fluctuation problem caused by uneven temperature. Simultaneously, for special steel grades sensitive to heating temperature, such as Cu-containing steel and IF steel, the surface peeling defect caused by excessively high temperatures in the middle of slab 200 is significantly improved. The peeling defect rate for Cu-containing steel decreased from 8.5% to 1.2%, and for IF steel from 6.3% to 0.8%, resulting in a significant increase in product qualification rate. Furthermore, the improvement in the same-slab temperature reduces rolling force, crown, and dimensional fluctuations during the rolling process, enhancing rolling stability, which is beneficial for producing high-precision strip steel products and extending equipment lifespan.

[0051] Furthermore, in the S300 heating step, the temperature of the slab 200 in the first heating section 103 is obtained. When the temperature of the slab 200 in the first heating section 103 is too high, the heating power of the heating nozzle in the second heating section 103 is reduced; when the temperature of the slab 200 in the first heating section 103 is too low, the heating power of the heating nozzle in the second heating section 103 is increased; after heating, the temperature difference along the length of the slab 200 is controlled within 25°C.

[0052] Specifically, the control system monitors the actual temperature of the slab 200 after passing through the first heating section 103 in real time. When the detected temperature is higher than the target value, the heating power of the second heating section 103 is automatically reduced; when the detected temperature is lower than the target value, the heating power of the second heating section 103 is automatically increased. Through dynamic adjustment, it is ensured that the slab 200 reaches the target temperature before entering the soaking section 104, and the temperature difference along the length of the slab 200 is ultimately controlled within 25°C.

[0053] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0054] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A heating furnace for improving the heating difference between slabs, characterized in that, include: The furnace body (100) is provided with a heat recovery section (101), a preheating section (102), a heating section (103) and a heat soaking section (104) in sequence along the conveying direction of the slab (200); An exhaust fan (300) is provided in the heat recovery section (101) to create a negative pressure in the furnace so that high-temperature flue gas flows from the heat soaking section (104) toward the heat recovery section (101); A partition wall (400) is provided in multiple ways and is spaced apart along the conveying direction of the slab (200) and located between two adjacent heating zones. A guide port (401) is provided on the top of the partition wall (400) and the guide port (401) is located in the middle of the width direction of the partition wall (400). The guide port (401) is used to guide the high-temperature flue gas on the lower surface of the middle part of the slab (200) to flow away from the slab (200) and flow through the guide port (401) to the heat recovery section (101) to reduce the heating temperature of the middle part of the slab (200).

2. The heating furnace for improving the heating difference of slabs as described in claim 1, characterized in that, It also includes a support conveyor (500) and a support column (600), the support column (600) is disposed inside the furnace body (100), the support conveyor (500) is mounted on the support column (600) and is spaced apart along the width direction of the furnace body (100) for supporting and conveying slabs (200).

3. The heating furnace for improving the heating difference of slabs as described in claim 2, characterized in that, The supporting conveyor (500) includes staggered fixed beams (501) and movable beams (502). The fixed beams (501) are used to support the slab (200), and the movable beams (502) are used to drive the slab (200) to move along the length of the furnace body (100).

4. The heating furnace for improving the heating difference of slabs as described in claim 1, characterized in that, It also includes a heating assembly, which includes a plurality of heating nozzles spaced apart on the furnace body (100) along the conveying direction of the slab (200). The heating nozzles are located on both sides of the preheating section (102), the heating section (103) and the homogenizing section (104) and are arranged symmetrically.

5. The heating furnace for improving the heating difference between slabs as described in claim 4, characterized in that, The heating nozzle includes an upper nozzle (700) disposed on the upper half of the furnace body (100) and a lower nozzle (701) disposed on the lower half of the furnace body (100).

6. The heating furnace for improving the heating difference between slabs as described in claim 4, characterized in that, The heating section (103) includes a first heating section (103) and a second heating section (103). The heating power of the heating nozzles of the first heating section (103) and the second heating section (103) is independently controlled to adjust the heating intensity according to the temperature of the slab (200).

7. The heating furnace for improving the heating difference between slabs as described in claim 5, characterized in that, The partition wall (400) has a height of 1.1~1.3m and a distance of 0.49~0.51m from both sides of the furnace wall. The guide port (401) is rectangular, with a width of 0.6-0.8m and an opening height of 0.3-0.5m. The height of the lower edge of the guide port (401) from the furnace bottom matches the height of the centerline of the lower nozzle (701).

8. The heating furnace for improving the heating difference between slabs as described in claim 1, characterized in that, The induced draft device (300) is an induced draft fan used to drive the high-temperature flue gas from the heat equalization section (104) to the heat recovery section (101).

9. A method of using a heating furnace for improving the heating uniformity of slabs (200), wherein the slab (200) is heated using a heating furnace for improving the heating uniformity of slabs (200) as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S100, the slab to be heated (200) is placed into the heating furnace, so that the slab (200) is placed on the support conveyor (500); S200, the slab (200) is heated sequentially through a heat recovery section (101), a preheating section (102), a heating section (103) and a soaking section (104). The heating section (103) includes a first heating section (103) and a second heating section (103). The heating power of the first heating section (103) and the second heating section (103) is independently controlled according to the temperature of the slab (200). S300 During the heating process, a negative pressure is formed in the furnace by the induced draft device (300), which causes the high-temperature flue gas to flow from the heat homogenization section (104) to the heat recovery section (101). The high-temperature flue gas on the lower surface of the middle part of the slab (200) is guided to flow away from the slab (200) through the guide port (401) at the top of the partition wall (400), and flows to the heat recovery section (101) through the guide port (401) to reduce the heating temperature of the middle part of the slab (200). S400, the slab (200) after heating is completed is sent out from the soaking section (104).

10. The method of using the heating furnace for improving the heating difference of slabs as described in claim 9, characterized in that, In the S300 heating step, the temperature of the slab (200) in the first heating section (103) is obtained. When the temperature of the slab (200) in the first heating section (103) is too high, the heating power of the heating nozzle in the second heating section (103) is reduced. When the temperature of the slab (200) in the first heating section (103) is too low, the heating power of the heating nozzle in the second heating section (103) is increased. The temperature difference along the length of the slab (200) after heating is controlled within 25°C.

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