Cover type annealing furnace and annealing process thereof

Abstract

The invention discloses a bell-type annealing furnace and an annealing process thereof, and relates to the technical field of bell-type annealing furnaces, the bell-type annealing furnace comprises a furnace platform, a composite bearing ring is arranged at the upper part of the furnace platform, a guide plate is arranged at the upper part of the composite bearing ring, a plurality of steel belts are arranged at the upper part of the guide plate, and the guide plate is arranged between every two adjacent steel belts; a reinforcing beam is arranged at the bottom of the coil base; the composite bearing ring comprises an outer ring and an inner ring, and the outer ring and the inner ring are both designed to be of a double-layer concentric structure. Through the design of the double-layer concentric composite bearing ring, the contact area of the bottom when the steel belt is placed is increased, the contact pressure is uniformly distributed, local deformation is reduced, the design of a coil base and a pot bottom in the prior art is eliminated, a guide plate-reinforcing plate direct connection structure is adopted, the deformation risk is reduced, and the stability is improved; and meanwhile, the structural rigidity and the equipment operation safety are improved through a bottom plate reinforcing beam and an embedded strain monitoring system, dynamic compensation is achieved through the laser three-dimensional scanning calibration technology, and it is ensured that the flatness of the coil base is accurately controlled.

Description

Technical Field

[0001] The invention relates to the technical field of bell-type annealing furnaces, in particular to a bell-type annealing furnace and an annealing process thereof. Background Art

[0002] In the production of steel plates, annealing is needed to eliminate the work hardening produced during the cold rolling process, improve the plasticity and toughness of the steel plates, and improve their processing performance to meet the needs of the automotive, home appliance, construction and other industries for high-quality steel plates. The bell-type annealing furnace can adapt to the annealing of steel coils of different specifications and materials, providing a guarantee for the production of diversified steel products. The bell-type annealing furnace is an important equipment for the heat treatment of cold-rolled steel, mainly composed of a furnace table, a heating hood and a cooling hood; the energy utilization efficiency of the early bell-type annealing furnace was low. With the emergence of the energy crisis and the emphasis on energy conservation and emission reduction, high-efficiency combustion technology and waste heat recovery technology have been applied to bell-type annealing furnaces, such as The use of advanced burners improves fuel combustion efficiency, and the use of heat exchangers to recover waste heat from flue gas for preheating air or workpieces reduces energy consumption. The development of automated control technology enables precise control of process parameters such as temperature, atmosphere, and pressure of bell-type annealing furnaces. Through computer control systems, real-time monitoring and adjustment of the annealing process can be achieved, improving the stability and consistency of annealing quality and reducing the impact of human factors on production. High-temperature resistant, corrosion-resistant, and high-strength materials continue to emerge, providing better options for the manufacture of key components such as the inner cover and heating elements of bell-type annealing furnaces, and improving the service life and reliability of the equipment. For example, the use of new insulation materials such as ceramic fibers can effectively reduce the heat loss of the furnace body and improve insulation performance.

[0003] As a core component, the furnace table carries processed materials such as steel coils. Its structural design directly affects the stability of the annealing process and the quality of the product. At present, the hood annealing furnace table design widely used at home and abroad has problems such as uneven stress distribution and easy deformation, which leads to short equipment life and high maintenance frequency, thus affecting production efficiency and product quality. With the growing demand for high-quality products in the cold-rolled steel market, higher requirements are placed on the structural optimization of the hood annealing furnace. It is necessary to design a hood annealing furnace and its annealing process to solve the above-mentioned problems. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a bell-type annealing furnace and an annealing process thereof to solve the problems of uneven stress distribution and easy deformation in the furnace table design in the above technical solution.

[0005] To achieve the above object, the present invention is realized through the following technical solutions: A bell-type annealing furnace includes a furnace platform. A composite load-bearing ring is provided on the upper part of the furnace platform. A flow guide plate is provided on the upper part of the composite load-bearing ring. A plurality of steel belts are provided on the upper part of the flow guide plate. A flow guide plate is provided between adjacent two steel belts. A strengthening beam is provided at the bottom of the furnace platform; The composite load-bearing ring includes an outer ring and an inner ring. Both the outer ring and the inner ring are double-layer structures up and down, and the outer ring and the inner ring are designed with a concentric structure. A plurality of connecting columns are equally spaced between the outer ring and the inner ring. A plurality of support columns are welded and connected at equal intervals at the bottom end of the outer ring at the bottom. The bottom ends of the support columns are fixedly connected with strengthening plates. The strengthening plates are all welded to the upper end of the furnace platform.

[0006] Further, the diameter of the outer ring is 3600 mm, the cross-section is a square structure of 300*300 mm, and the wall thickness is 15 mm. The diameter of the inner ring is 3200 mm, the cross-section is a T-shaped structure with a web height of 150 mm and a flange width of 200 mm. Both the outer ring and the inner ring are made of 06Cr19Ni10 stainless steel.

[0007] Further, the diameter of the support column is 200 mm, the wall thickness is 20 mm, and the size of the strengthening plate is 400*400*15 mm.

[0008] Further, the flow guide plates are all designed with a honeycomb sandwich structure. The surface layer is 2 mm thick 316L stainless steel, and the sandwich core layer is 50 mm thick ceramic fiber.

[0009] Further, the strengthening beam adopts a grid structure, the cross-section is 400*400 mm, the wall thickness is 20 mm, and it is made of Q460C high-strength steel. M64 anchor bolts are embedded at the beam nodes of the strengthening beam.

[0010] Further, a bell-type annealing furnace annealing process includes the following annealing process steps: S1. Preliminary preparation: Clean the bell-type annealing furnace, remove the dirt and sundries on the outer cover, inner cover, furnace platform, outer ring and inner ring, and check the heating elements and temperature control system in the furnace to ensure their normal operation. At the same time, check the parameters of the corresponding annealing process for the steel belt to be processed, and then detect the flatness of the furnace platform through a laser scanner and record the detection data; S2. Loading: Place a layer of flow guide plate on the upper part of the composite load-bearing ring. Place the bottom steel belt on the upper part of the flow guide plate. Place a layer of flow guide plate at the bottom of each layer of steel belt. At the same time, place the flow guide plate and the steel belt neatly so that the flow guide plate and the steel belt are both at the same center position. Then open the furnace doors of the outer cover and the inner cover, and arrange fiber Bragg grating sensors at key positions of the flow guide plate. Secondly, hoist and install the inner cover and the outer cover in sequence. The inner cover covers the upper part of the furnace platform and covers the upper structure of the furnace platform. The outer cover covers the inner cover; S3. Heating: After the loading is completed, close the door of the bell-type annealing furnace and start the heating process. The heating rate is 5 °C / min. Set appropriate heating temperature and holding time according to the properties of the material and process requirements. Heat the steel strip through the heating element to reach the annealing temperature. The annealing temperature of the carbon steel strip is 750 °C, and it is heated for 150 min after reaching the heating temperature. The annealing temperature of the stainless steel strip is 1050 °C, and it is heated for 200 min after reaching the heating temperature. S4. Holding: After the steel strip reaches the annealing temperature, hold it. The holding time of the carbon steel strip is 120 min, and the holding time of the stainless steel strip is 180 min. S5. Cooling: After the holding time ends, use deionized water as the cooling medium and carry out spray cooling. The spray speed is controlled at 5 l / min. The cooling time of the carbon steel strip is 150 min, and the cooling time of the stainless steel strip is 220 min. S6. Unloading: When the steel strip cooling is completed, use a lifting form with a rated lifting capacity of 10 - 15 tons to take out the outer cover and inner cover in turn. S7. Quality inspection: Detect the hardness, mechanical properties and dimensional accuracy of the annealed steel strip. At the same time, use a laser scanner to detect the flatness of the furnace platform again, and compare the data of the flatness of the furnace platform before annealing with that after annealing. S8. Recording: During the processes of S1 - S8, record the heating temperature, heating time, holding time, cooling time and quality inspection data in detail. The recording frequency is once every 10 min. S9. Maintenance: Regularly carry out maintenance work on the bell-type annealing furnace.

[0011] Furthermore, in the S1 step, the installation errors of the outer cover, inner cover, furnace platform, outer ring, inner ring and steel strip are controlled within ±5 mm; the measurement accuracy of the fiber Bragg grating sensor is ±1 με, and it monitors the strain change in real time. When the local strain > 2000 με, an early warning is triggered.

[0012] Furthermore, in the S7 step, use a Rockwell hardness tester to evenly select 10 detection points on the steel strip to detect the hardness of the annealed steel strip; use the method of tensile specimens to detect the mechanical properties of the annealed steel strip; use a micrometer with an accuracy of 0.01 mm to detect the thickness and width of the annealed steel strip, and detect it once every 1 m, for a total of 5 times.

[0013] In summary, the present invention provides a bell-type annealing furnace and its annealing process, having the following beneficial effects: 1. Eliminate the design of the furnace top and the bottom of the pot in the prior art, adopt the direct connection structure of the deflector - reinforcement plate, reduce the risk of deformation, improve stability. At the same time, the bottom plate reinforcement beam and the embedded strain monitoring system further enhance the overall structural stiffness and the safety of equipment operation, and adopt the laser three-dimensional scanning calibration technology to achieve dynamic compensation, ensuring the precise control of the flatness of the furnace top.

[0014] 2. The double-layer concentric composite load-bearing ring design increases the contact area at the bottom when the steel strip is placed, evenly distributes the contact pressure, reduces local deformation. At the same time, the deflector with a honeycomb sandwich structure improves the bending stiffness and the air flow uniformity.

[0015] 3. By adopting the composite load-bearing ring, the deflector and the reinforcement beam, and in the annealing process of the steel strip, with rigorous preliminary preparation, precise heating rate control, temperature and time parameter setting adapted to different materials, combined with precise cooling control, ensure the precise regulation of the microstructure of the steel strip, meet the annealing quality requirements of different materials such as carbon steel and stainless steel, and adopt a comprehensive detection and recording process to effectively guarantee the product quality stability and improve the traceability of the production process and the process reliability. Description of the Drawings

[0016] Figure 1 It is a three-dimensional structural schematic diagram of a bell-type annealing furnace of the present invention; Figure 2 It is a three-dimensional structural schematic diagram of the furnace top, the composite load-bearing ring and the steel strip of a bell-type annealing furnace of the present invention; Figure 3 It is a three-dimensional structural schematic diagram of the composite load-bearing ring of a bell-type annealing furnace of the present invention; Figure 4 It is a three-dimensional structural schematic diagram of the reinforcement beam of a bell-type annealing furnace of the present invention; Figure 5 It is a structural schematic diagram of the deflector of a bell-type annealing furnace of the present invention.

[0017] Description of the Reference Numerals in the Drawings: 1, furnace top; 2, composite load-bearing ring; 201, outer ring; 202, connecting column; 203, inner ring; 204, support column; 205, reinforcement plate; 3, deflector; 4, reinforcement beam; 5, steel strip. Detailed Embodiments

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] Embodiment 1: See also Figure 1 - Figure 5 As shown, the present invention provides a bell-type annealing furnace, comprising a furnace table 1, a composite load-bearing ring 2 is arranged on the upper part of the furnace table 1, a guide plate 3 is arranged on the upper part of the composite load-bearing ring 2, a plurality of steel belts 5 are arranged on the upper part of the guide plate 3, a guide plate 3 is arranged between two adjacent steel belts 5, and a reinforcing beam 4 is arranged at the bottom of the furnace table 1; The composite load-bearing ring 2 includes an outer ring 201 and an inner ring 203. The outer ring 201 and the inner ring 203 are both double-layer structures, and the outer ring 201 and the inner ring 203 adopt a concentric structure design. The upper and lower outer rings 201 and the inner ring 203 are connected by welding. A number of connecting columns 202 are equidistantly arranged between the outer ring 201 and the inner ring 203, and the outer ring 201 and the inner ring 203 are welded together. The bottom end of the bottom outer ring 201 is equidistantly welded with a number of supporting columns 204, and the bottom ends of the supporting columns 204 are fixedly connected with reinforcing plates 205, and the reinforcing plates 205 are welded to the upper end of the furnace table 1.

[0020] See also Figure 2 and Figure 3 As shown, the outer ring 201 has a diameter of 3600 mm, a 300*300 mm square structure, and a wall thickness of 15 mm. The inner ring 203 has a diameter of 3200 mm, and a T-shaped structure with a web height of 150 mm and a flange width of 200 mm. The outer ring 201 and the inner ring 203 are both made of 06Cr19Ni10 stainless steel. The double-ring design increases the contact area between the steel belt 5 and the furnace table 1 to 85%, and improves the uniformity of contact pressure distribution by 40%.

[0021] See also Figure 3 As shown, the diameter of the support column 204 is 200 mm, the wall thickness is 20 mm, and the size of the reinforcement plate 205 is 400*400*15 mm. Finite element simulation verification shows that this design improves the load transfer efficiency to 98% and reduces the maximum equivalent stress to 220 MPa (safety factor 1.56).

[0022] See also Figure 5 As shown, the guide plates 3 are all designed with a honeycomb sandwich structure, with a surface layer of 2 mm thick 316L stainless steel and a sandwich core layer of 50 mm thick ceramic fiber. The bending stiffness is increased by 3 times, and the opening rate of the support plate is optimized to 38% (originally 30%-40%). The airflow uniformity index is confirmed to be greater than 0.92 through CFD simulation.

[0023] See also Figure 4 As shown, the reinforcing beam 4 adopts a tic-tac-toe structure, with a cross-section of 400*400mm, a wall thickness of 20mm, and is made of Q460C high-strength steel. M64 anchor bolts are embedded at the beam nodes of the reinforcing beam 4, and the overall structural rigidity is increased by 60%.

[0024] Example 2: The present invention provides a bell-type annealing furnace annealing process, including the following annealing process steps: S1. Preliminary preparation: Clean the bell-type annealing furnace, remove dirt and debris on the outer cover, inner cover, furnace table 1, outer ring 201 and inner ring 203, and check the heating elements and temperature control system in the furnace to ensure their normal operation. At the same time, check the parameters of the corresponding annealing process for the steel strip 5 to be processed, then detect the flatness of the furnace table 1 through a laser scanner, record the detection data. The cleaning equipment can remove dirt and debris that affect heat transfer and equipment life; checking the components and systems can ensure stable operation; detecting the flatness of the furnace table 1 provides basic data support for subsequent loading and product quality, and avoids product defects caused by problems with the furnace table 1; S2. Loading: Place a layer of flow guide plate 3 on the upper part of the composite load-bearing ring 2, place the bottom steel strip 5 on the upper part of the flow guide plate 3, and place a layer of flow guide plate 3 at the bottom of each layer of steel strip 5. At the same time, place the flow guide plate 3 and the steel strip 5 neatly so that the flow guide plate 3 and the steel strip 5 are both at the same center position. Then open the furnace doors of the outer cover and the inner cover, and arrange fiber Bragg grating sensors at key positions of the flow guide plate 3. Secondly, hoist and install the inner cover and the outer cover in sequence. The inner cover covers the upper part of the furnace table 1, covering the upper structure of the furnace table 1, and the outer cover covers the inner cover. Reasonably place the flow guide plate 3 and the steel strip 5 to ensure uniform heat transfer; installing fiber Bragg grating sensors can monitor strain in real time, prevent abnormal deformation from affecting product quality, and ensure the accuracy and standardization of the loading link, laying a good foundation for the subsequent annealing process; S3. Heating: After the loading is completed, close the furnace doors of the inner cover and the outer cover of the bell-type annealing furnace, and start the heating process. The heating rate is 5°C / min. According to the properties of the material and process requirements, set appropriate heating temperature and holding time, and heat the steel strip 5 through the heating elements to make it reach the annealing temperature. The annealing temperature of the carbon steel strip is 750°C, and it is heated for 150 min after reaching the heating temperature. The annealing temperature of the stainless steel strip is 1050°C, and it is heated for 200 min after reaching the heating temperature. Accurately control the heating rate, and set appropriate temperature and duration according to different materials, which can promote the full diffusion of atoms inside the steel strip, optimize the organizational structure, meet the annealing requirements of different materials such as carbon steel and stainless steel, and ensure product performance; S4. Holding: After the steel strip 5 reaches the annealing temperature, hold it. The holding time of the carbon steel strip is 120 min, and the holding time of the stainless steel strip is 180 min. Maintain a specific temperature for a period of time to make the structure transformation of the steel strip 5 more sufficient and uniform, eliminate internal stress, improve the comprehensive performance of the material, ensure the stability of product quality, and reduce performance fluctuations; S5, Cooling: After the holding time ends, deionized water is used as the cooling medium, and the cooling is carried out by spray cooling. The spray speed is controlled at 5 l / min. The cooling time of the carbon steel strip is 150 min, and the cooling time of the stainless steel strip is 220 min. Spray cooling with deionized water is used to accurately control the cooling speed, avoid internal stress and deformation caused by uneven cooling, ensure that the microstructure of the steel strip meets the requirements, and improve the dimensional accuracy and surface quality of the product; S6, Unloading: After the steel strip 5 is cooled, a lifting form with a rated lifting capacity of 10 - 15 tons is used to remove the outer cover and the inner cover in sequence. Standard lifting operations can prevent damage to the outer cover, the inner cover and the equipment in the furnace, ensure equipment safety, create good conditions for the next production, and ensure production continuity; S7, Quality Inspection: The hardness, mechanical properties and dimensional accuracy of the annealed steel strip are detected. At the same time, the flatness of the furnace platform 1 is detected again by using a laser scanner, and the flatness data of the furnace platform 1 before annealing and after annealing are compared. The performance and dimensional accuracy of the steel strip are comprehensively detected, and the flatness of the furnace platform before and after annealing is compared to timely discover problems in the production process, control product quality, and provide a basis for process optimization; S8, Recording: During the process of S1 - S8, the heating temperature, heating time, holding time, cooling time and quality inspection data are recorded in detail. The recording frequency is once every 10 min. Timely and detailed recording of key data is convenient for tracing the production process, analyzing the influence of each link on product quality, assisting process improvement, and improving production stability and controllability; S9, Maintenance: Regular maintenance work is carried out on the bell - type annealing furnace. Regular maintenance can timely discover and solve potential problems of the equipment, extend the service life of the equipment, reduce the failure rate, ensure efficient and continuous production, and improve the economic benefits of the enterprise.

[0025] In step S1, the outer cover, the inner cover, the furnace platform 1, the outer ring 201 and the inner ring 203 are carefully cleaned to ensure that the surface is free of dirt, oil, iron filings and dust. The cleaning time is 1 - 2 h. At the same time, a professional electrical detection instrument is used to test the resistance and insulation of the heating element, and check the sensor accuracy of the temperature control system. The accuracy of the laser scanner is ±0.05 mm / m, and the adjustment accuracy is ±0.1 mm. Scanning is carried out in a grid - like distribution with a spacing of 200 mm, and the scanning data is recorded. Careful cleaning can eliminate impurities that affect heat transfer and equipment corrosion, extend the equipment life, and electrical detection ensures the accurate operation of the heating element and temperature control. High - precision laser scanning of the furnace platform comprehensively grasps the flatness, provides reliable data for loading and product quality, and prevents potential quality hazards.

[0026] In step S2, the installation error between the deflector 3 and the steel strip 5 is controlled within ±5 mm; the measurement accuracy of the fiber Bragg grating sensor is ±1 με, which monitors the strain change in real time. When the local strain > 2000 με, an early warning is triggered. The installation error is strictly controlled to ensure that the heat is evenly conducted to the steel strip. The high-precision fiber Bragg grating sensor monitors the strain in real time, gives an early warning of anomalies in a timely manner, ensures that no harmful deformation occurs to the steel strip during the loading and subsequent annealing processes, and maintains the stability of the product quality.

[0027] In step S7, a Rockwell hardness tester is used to evenly select 10 detection points on the steel strip 5 to detect the hardness of the steel strip 5 after annealing; the mechanical properties of the steel strip 5 after annealing are detected by means of a tensile specimen; a micrometer with a precision of 0.01 mm is used to detect the thickness and width of the steel strip 5 after annealing, and it is detected once every 1 m for a total of 5 times. The multi-point detection by the Rockwell hardness tester ensures comprehensive and accurate hardness data. The tensile specimen can truly reflect the mechanical properties. The high-precision micrometer detects the thickness and width at multiple positions, comprehensively controls the dimensional accuracy of the product, helps to accurately evaluate the annealing quality, and provides a key basis for process optimization.

[0028] Example 3: This example is about the implementation effect of a laser scanner and the data recording of the laser scanner and fiber Bragg grating sensor in a bell-type annealing furnace annealing process: 1. Comparison of the implementation effects of the laser scanner: parameter Original structure Optimized structure Improvement Maximum deformation (10^4h) 5mm 0.8mm 84％ Deflector inclination angle deviation 0.5° 0.08° 84％ Structural service life 3-5 years 8-10 years 167％ Maintenance frequency 2 times / year 0.5 times / year 167％ 2. Data recording of the laser scanner: The difference value is the difference between the front-back and left-right detection data. A + value indicates that the flatness of furnace platform 1 tilts upward after use, and a - value indicates that the flatness of furnace platform 1 tilts downward after use.

[0029] 3. Data recording of the fiber Bragg grating sensor: The variable is the difference between the temperature data detected by the fiber Bragg grating sensor each time and the temperature data detected last time. A + value indicates an increase in temperature, and a - value indicates a decrease in temperature; the difference quantity is the difference between the value detected by the fiber Bragg grating sensor and the set temperature value.

[0030] This not only facilitates the storage of data but also is conducive to data comparison, and can intuitively understand the structural changes of the furnace platform before and after production.

[0031] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A bell-type annealing furnace, comprising a furnace table (1), characterized in that: A composite load-bearing ring (2) is arranged on the top of the furnace platform (1), a guide plate (3) is arranged on the top of the composite load-bearing ring (2), a plurality of steel belts (5) are arranged on the top of the guide plate (3), and a guide plate (3) is arranged between two adjacent steel belts (5), and a reinforcing beam (4) is arranged at the bottom of the furnace platform (1); The composite load-bearing ring (2) comprises an outer ring (201) and an inner ring (203), the outer ring (201) and the inner ring (203) both being upper and lower double-layer structures, and the outer ring (201) and the inner ring (203) are designed with a concentric structure, a plurality of connecting columns (202) are evenly spaced between the outer ring (201) and the inner ring (203), a plurality of supporting columns (204) are evenly welded to the bottom end of the outer ring (201), the bottom ends of the supporting columns (204) are fixedly connected to reinforcing plates (205), and the reinforcing plates (205) are welded to the upper end of the furnace platform (1).

2. A bell-type annealing furnace according to claim 1, characterized in that: The outer ring (201) has a diameter of 3600 mm, a cross-section of a square structure of 300*300 mm, and a wall thickness of 15 mm. The inner ring (203) has a diameter of 3200 mm, a cross-section of a T-shaped structure with a web height of 150 mm and a flange width of 200 mm. Both the outer ring (201) and the inner ring (203) are made of 06Cr19Ni10 stainless steel.

3. A bell-type annealing furnace according to claim 1, characterized in that: The support column (204) has a diameter of 200 mm and a wall thickness of 20 mm, and the reinforcement plate (205) has a size of 400*400*15 mm.

4. A bell-type annealing furnace according to claim 1, characterized in that: The guide plates (3) are all designed with a honeycomb sandwich structure, with a surface layer of 2 mm thick 316L stainless steel and a sandwich core layer of 50 mm thick ceramic fiber.

5. The bell-type annealing furnace according to claim 1, characterized in that: The reinforcing beam (4) adopts a tic-tac-toe structure, has a cross-section of 400*400 mm, a wall thickness of 20 mm, and is made of Q460C high-strength steel. M64 anchor bolts are pre-embedded at the beam nodes of the reinforcing beam (4).

6. A bell annealing furnace annealing process, based on the bell annealing furnace according to any one of claims 1 to 5, characterized in that: The annealing process comprises the following steps: S1, preliminary preparation: cleaning the bell-type annealing furnace, removing dirt and debris on the outer cover, inner cover, furnace table (1), outer ring (201) and inner ring (203), and checking the heating elements and temperature control system in the furnace to ensure their normal operation, and at the same time checking the parameters of the corresponding annealing process for the steel strip (5) to be treated, and then detecting the flatness of the furnace table (1) by a laser scanner, and recording the detection data; S2, charging: a layer of guide plate (3) is placed on the upper part of the composite load-bearing ring (2), a bottom layer of steel belt (5) is placed on the upper part of the guide plate (3), and a layer of guide plate (3) is placed on the bottom of each layer of steel belt (5). At the same time, the guide plate (3) and the steel belt (5) are neatly placed so that the guide plate (3) and the steel belt (5) are at the same center position, and then the furnace doors of the outer cover and the inner cover are opened, and the fiber optic Bragg grating sensor is arranged at the key position of the guide plate (3). Then, the inner cover and the outer cover are hoisted and installed in sequence, and the inner cover is placed on the upper part of the furnace platform (1), and the upper structure of the furnace platform (1) is covered, and the outer cover covers the inner cover; S3, heating: after the loading is completed, the furnace doors of the inner and outer hoods of the hood annealing are closed, and the heating process is started. The heating rate is 5°C / min. According to the properties of the material and the process requirements, the appropriate heating temperature and holding time are set. The steel strip (5) is heated by the heating element to reach the annealing temperature. The annealing temperature of the carbon steel strip is 750°C, and the heating time is 150 minutes after reaching the heating temperature. The annealing temperature of the stainless steel strip is 1050°C, and the heating time is 200 minutes after reaching the heating temperature. S4, insulation: after the steel strip (5) reaches the annealing temperature, it is kept warm. The insulation time of the carbon steel strip is 120 minutes, and the insulation time of the stainless steel strip is 180 minutes; S5. Cooling: After the holding time is over, deionized water is used as the cooling medium and the cooling is carried out in a spray cooling manner. The spray speed is controlled at 5l / min. The cooling time of the carbon steel strip is 150min and the cooling time of the stainless steel strip is 220min. S6. Removing materials: When the steel strip (5) is cooled, the outer cover and the inner cover are removed in sequence by hoisting with a rated lifting capacity of 10-15 tons; S7, quality inspection: the hardness, mechanical properties and dimensional accuracy of the annealed steel strip are tested, and the flatness of the furnace table (1) is tested again using a laser scanner, and the data of the flatness of the furnace table (1) before annealing is compared with the flatness of the furnace table (1) after annealing; S8, record: in the process of S1-S8, the heating temperature, heating time, holding time, cooling time and quality inspection data are recorded in detail, and the recording frequency is once every 10 minutes; S9. Maintenance: Regularly perform maintenance work on the bell-type annealing furnace.

7. The bell annealing furnace annealing process according to claim 6, characterized in that: In step S1, the outer cover, inner cover, furnace table (1), outer ring (201) and inner ring (203) are carefully cleaned to ensure that the surfaces are free of dirt, oil, iron filings and dust. The cleaning time is 1-2 hours. At the same time, a resistance test and an insulation test are performed on the heating element using a professional electrical testing instrument to check the sensor accuracy of the temperature control system. The laser scanner has an accuracy of ±0.05 mm / m and an adjustment accuracy of ±0.1 mm. A grid distribution with a spacing of 200 mm is used for scanning, and the scanning data is recorded.

8. The bell-type annealing furnace annealing process according to claim 6, characterized in that: In step S2, the installation error of the guide plate (3) and the steel belt (5) is controlled within ±5 mm; the measurement accuracy of the fiber optic Bragg grating sensor is ±1 με, and the strain change is monitored in real time, and an early warning is triggered when the local strain is greater than 2000 με.

9. The bell annealing furnace annealing process according to claim 6, characterized in that: In step S7, a Rockwell hardness tester is used to evenly select 10 test points on the steel strip (5) to test the hardness of the steel strip (5) after annealing; a tensile test specimen is used to test the mechanical properties of the steel strip (5) after annealing; and a micrometer with an accuracy of 0.01 mm is used to test the thickness and width of the steel strip (5) after annealing, and the test is performed every 1 m, for a total of 5 times.

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