A method of using a horizontal coil base for annealing a steel coil from a ring furnace

Abstract

The application belongs to the technical field of silicon steel heat treatment equipment, and discloses a use method of a horizontal coil bottom base for ring furnace steel coil annealing, wherein the horizontal coil bottom base is an integral annular bearing saddle base, is made of ZG40Cr25 and trace element rare earth reinforced high-chromium nickel austenitic heat-resistant cast steel material, is made through integral precision casting, high-temperature forging densification and plane finishing, has a total height of 200 mm, and has a single-piece weight of 1803 kg. The use method of the horizontal coil bottom base for ring furnace steel coil annealing changes the traditional vertical placement of the silicon steel coil into lateral placement with coaxial bearing, so that the steel coil gravity is evenly distributed along the circumferential direction, and the bearing deformation of the lower end edge of the steel coil caused by concentrated stress in the vertical state is completely avoided. The change is beneficial to the uniform secondary recrystallization of the oriented silicon steel in the high-temperature annealing process, and effectively prevents the decrease of magnetic permeability and the increase of iron loss.

Description

Technical Field

[0001] This invention relates to the field of silicon steel heat treatment equipment technology, belonging to the category of green manufacturing of ultra-high grade oriented silicon steel. Specifically, it relates to a method of using a horizontal coil base for annealing steel coils in an annular furnace. Background Technology

[0002] Silicon steel is a core soft magnetic functional material for equipment such as power transformers, motors, and instrument transformers. Its key properties, such as magnetic permeability, iron loss, and magnetic flux density, are highly dependent on the high-temperature annealing and reduction process. At present, the industry generally uses an inner-shell type annular preheating furnace to anneal silicon steel coils: the silicon steel coils are placed vertically on the chassis, and the inner shell is fastened to form a closed heat treatment cavity. The external combustion chamber is heated by burners, and the heat is transferred into the furnace through the inner shell by radiation and convection, so that the steel coils can complete recrystallization, decarburization, reduction, and microstructure homogenization under high temperature and protective atmosphere. In this thermal system, the chassis saddle bears three major functions: heavy load support, high temperature structural stability, and uniform heat transfer interface. The traditional chassis materials are mainly ZG40Cr25Ni20, 310S, and ordinary high chromium cast iron. The manufacturing process is mainly single casting and welding assembly. The structure is mainly simple bare plate and low rigidity stiffener. Under repeated service conditions at ultra-high temperature of 1200℃, the traditional components deteriorate rapidly, resulting in poor annealing, scrapped steel coils, and high equipment downtime rate. It has become a key equipment bottleneck for high-quality silicon steel production. Specifically, the following issues are addressed: First, heat treatment efficiency and quality are limited. Existing chassis require refractory bricks to be laid at the bottom for support and heat transfer. The steel coils are placed vertically, and the nitrogen-hydrogen protective atmosphere has poor flowability and low thermal conductivity on the surface of the steel coils. The atmosphere cannot quickly penetrate into the interior of the steel coils, resulting in uneven temperature differences between the inside and outside of the steel coils, which prolongs the annealing cycle and affects the magnetic properties and surface quality of silicon steel. Secondly, the structural design is not adaptable enough. Due to its own weight, the lower edge of the steel coil is prone to deformation after being heated. This is especially detrimental to the uniform secondary recrystallization during high-temperature annealing of oriented silicon steel, which may lead to a decrease in magnetic permeability, an increase in iron loss, and a reduction in yield. Summary of the Invention

[0003] The purpose of this invention is to provide a method for using a horizontal coil base for annealing steel coils in an annular furnace, in order to solve the problems mentioned in the background art, such as the easy deterioration of existing annular furnace steel coil annealing bases under high-temperature service, uneven heat transfer leading to large temperature differences between the inside and outside of the steel coil, long annealing cycle, and the easy occurrence of load-bearing deformation at the lower edge of the steel coil when vertically supported, which affects the magnetic properties of silicon steel and the yield.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for using a horizontal coil base for annealing steel coils in an annular furnace, comprising: horizontally positioning an integral annular bearing saddle base plate inside the annular furnace, and placing a silicon steel coil on the bearing surface of the saddle base plate in a side-mounted manner, so that the center of the steel coil is aligned with the center of the base plate and the force is uniform. The inner cover is then fastened to form a sealed heat treatment chamber, and a protective atmosphere of H2-N2 is introduced for decarburization annealing. According to the silicon steel process curve, the temperature is raised to 1150-1200℃, and annealing is carried out in sequence through the heating section, the soaking section, and the heat preservation section, with heat preservation for 6-30 hours. The high flatness and high thermal conductivity of the chassis enable uniform heat transfer, keeping the temperature difference of the steel coil ≤15℃. Finally, the material is cooled to a suitable discharge temperature using a segmented controlled cooling method before being discharged, and the chassis is recycled and reused.

[0005] The horizontal roll base is an integral ring-shaped bearing saddle chassis, made of ZG40Cr25 and trace element rare earth reinforced high chromium nickel austenitic heat-resistant cast steel. It is made by integral precision casting, high temperature forging densification and surface finishing. The total height is 200mm, the weight of a single piece is 1803kg, the flatness of the bearing surface is ≤0.3mm / m, and the surface roughness Ra≤3.2μm.

[0006] Preferably, the chassis exhibits creep deformation ≤0.15% under 1200℃ and 50MPa load conditions for 1000h, and a normal service life ≥36 months.

[0007] By adopting the above technical solution, the chassis material is strengthened by rare earth and niobium microalloying and densified by high-temperature forging and compaction, which significantly improves the high-temperature creep resistance and oxidation resistance, avoids the problem of rapid deterioration, deformation and cracking of traditional cast components at high temperatures, greatly extends the service life of the base, and reduces equipment downtime and spare parts replacement costs.

[0008] Preferably, the contact area between the chassis and the steel coil is ≥95%, and the temperature difference between the steel coil cross sections is ≤15℃.

[0009] By adopting the above technical solution, the extremely high flatness and surface roughness of the chassis bearing surface ensure a tight fit with the bottom of the steel coil, significantly reducing contact thermal resistance, making the heat flux density uniformly distributed, and effectively eliminating hot and cold spots at the bottom of the steel coil, thereby ensuring the uniformity of the annealed structure and the fullness of the reduction.

[0010] Preferably, the chassis material has the following chemical composition by mass fraction: C 0.35-0.45, Cr 24.0-26.0, and niobium and rare earth trace elements are added for microalloying reinforcement.

[0011] Using the above technical solution, the high nickel content stabilizes the austenitic matrix, the high chromium forms a dense Cr2O3 oxide film, and the niobium precipitates NbC and NbN nano-dispersed phases to pin the grain boundaries, suppressing dislocation slip and changing the creep mechanism from grain boundary slip to diffusion creep. It can still maintain high creep strength (≥35MPa) and low static oxidation rate (≤0.08mm / year) at 1200℃.

[0012] Preferably, the manufacturing process of the chassis is as follows: electric arc furnace and ladle refining and smelting; sand casting or investment casting; constant temperature controlled pouring; high temperature forging and compaction; 1180℃ solution treatment and 900℃ aging treatment; surface grinding and precision turning.

[0013] By adopting the above technical solution, the overall precision casting combined with high-temperature forging eliminates internal shrinkage defects, the solution treatment and aging heat treatment optimize the grain boundary structure, and the final planar precision machining ensures the geometric accuracy of the bearing surface, giving the chassis excellent overall rigidity and hot dimensional stability.

[0014] Preferably, the side-mounted bearing arrangement of the steel coil ensures that the nitrogen-hydrogen mixed protective atmosphere uniformly and quickly surrounds the surface of the steel coil and penetrates into the interior, reducing the temperature difference between the inside and outside of the steel coil and preventing deformation of the steel coil edges under load.

[0015] By adopting the above technical solution, the horizontal side-laying method changes the stress state of the traditional vertical placement, so that the weight of the steel coil is evenly distributed along the circumference, which completely avoids the collapse deformation caused by concentrated stress at the lower edge. It is especially beneficial to the uniform secondary recrystallization during the high-temperature annealing process of grain-oriented silicon steel, and prevents the decrease in magnetic permeability and the increase in iron loss.

[0016] Preferably, the chassis has a maximum long-term service temperature of 1250℃, a creep strength of ≥35MPa at 1200℃, a high-temperature compressive strength of ≥320MPa, and a static oxidation rate of ≤0.08mm / year.

[0017] By adopting the above technical solution, the chassis can withstand the stringent requirements of various ultra-high temperature annealing processes for silicon steel. When used as a cooling fixture, N2 is used as a cooling atmosphere to participate in segmented controlled cooling, realizing integrated heat treatment in the furnace, which has excellent process adaptability and economy.

[0018] Preferably, the chassis center has stable support, the outer ring is uniformly stressed, the wall thickness is uniformly transitioned, there is no stress concentration, the overall rigidity is excellent, and the hot deflection f=5GL³ / (384EI)≤0.2mm; "Hot deflection" refers to the amount of deformation that occurs under high-temperature operating conditions.

[0019] Where f represents the maximum deflection (deformation), which is the maximum distance that the beam or base bends downward after being subjected to force.

[0020] G: Represents uniformly distributed load. G refers to the gravity per unit length (such as the self-weight of the chassis).

[0021] L: represents the span (the distance between support points). The longer the span, the more the deformation increases cubically.

[0022] 384: This is a constant, also derived from the boundary conditions (simply supported beam + uniformly distributed load) as a denominator coefficient.

[0023] E: Represents the elastic modulus, reflecting the hardness / stiffness of a material. This is the key to the "hot state". At high temperatures, the E value of steel will decrease significantly, resulting in an increase in f (increased deformation).

[0024] I represents the moment of inertia of the cross section. The thicker the wall and the more resistant the structure to bending, the larger the value of I and the smaller the deflection f.

[0025] By adopting the above technical solution, the ring structure and uniform wall thickness design eliminate the hidden danger of stress concentration in the welded assembly structure. Under heavy load and high temperature, the bending section modulus is large and the hot deflection is extremely small, providing a near-perfect uniform stress foundation for the steel coil and eliminating local overheating and steel coil deformation caused by chassis deflection.

[0026] Preferably, the H2-N2 protective atmosphere uses N2 as an inert gas to displace oxygen and H2 as a reducing gas to decarburize and anneal the steel coil.

[0027] By adopting the above technical solution, a nitrogen-hydrogen mixed atmosphere forms a uniform and rapid convection and penetration around the horizontally placed steel coil, which not only ensures an oxygen-free environment in the furnace, but also effectively removes oxides from the surface of the steel coil through the strong reducing effect of hydrogen, thereby improving the surface quality and magnetic properties of silicon steel.

[0028] Preferably, the heating section, the heat-spreading section, the heat-preserving section, and the cooling section constitute a segmented controlled cooling process, wherein N2 also serves as the cooling atmosphere; Heating stage: The furnace temperature needs to reach a high temperature of 1210-1250℃. This process is used for steel purification and secondary recrystallization. It is necessary to avoid excessive thermal stress by slowly increasing the temperature in a stepwise manner.

[0029] Cooling stage (critical): A four-stage progressive cooling process is employed, with an extremely long total duration, to protect magnetic properties and plate shape. Section 1C (slow cooling): The temperature drops the slowest (approximately ≤15℃ / h), gradually decreasing from 1210℃ to 1080℃; 2C Section (Slow Cooling): Continuous and slow cooling down, with a target temperature of 650℃, to prevent edge wave defects; 3C stage (rapid cooling): The temperature drops more rapidly, reaching around 350℃; 4C section (rapid cooling): Further cooling to below 270℃, maintaining extremely high temperature uniformity throughout the process; Atmosphere and cycle: The entire heat treatment process requires the introduction of a nitrogen-hydrogen mixed protective gas. Some processes require holding time of more than 150 hours. This is achieved through extremely slow cooling over several days to ensure that the silicon steel ultimately obtains excellent magnetic properties.

[0030] By adopting the above technical solution, through the coordinated control of segmented cooling and protective atmosphere, the steel coil was cooled steadily after annealing, avoiding thermal stress cracks caused by rapid cooling, while improving cooling efficiency and shortening the overall heat treatment cycle.

[0031] Compared with the prior art, the beneficial effects of the present invention are: the method of using the horizontal coil base for annealing steel coils in an annular furnace: 1. By changing the traditional vertical placement of silicon steel coils to a side-mounted or horizontally oriented bearing method, the weight of the coils is evenly distributed along the circumference, completely avoiding the load-bearing deformation or edge collapse caused by concentrated force at the lower edge of the coil in the vertical state. This change is conducive to the uniform secondary recrystallization of grain-oriented silicon steel during high-temperature annealing, effectively preventing the decrease in magnetic permeability and the increase in iron loss, and significantly improving the yield and product consistency of high-grade silicon steel. 2. The horizontal side-laying method allows the nitrogen-hydrogen mixed protective atmosphere to circulate and penetrate into the interior of the steel coil uniformly and quickly, significantly improving the uniformity of heat transfer and atmosphere distribution. Combined with the extremely high flatness (≤0.3mm / m) and excellent thermal conductivity of the chassis bearing surface, the temperature difference of the steel coil cross section is strictly controlled within ≤15℃. This effectively solves the problems of large temperature difference between the inside and outside of the steel coil and uneven annealing caused by traditional vertical placement, shortens the annealing cycle, and improves the magnetic permeability and surface quality of silicon steel. 3. The chassis is made of ZG40Cr25+rare earth / niobium microalloyed reinforced high chromium nickel austenitic heat-resistant cast steel. It is precision cast, high temperature forging densification and solution + aging heat treatment. Under the conditions of 1200℃ and 50MPa, the creep deformation is ≤0.15%, the endurance strength is ≥35MPa, and the static oxidation rate is ≤0.08mm / year. Its integral ring structure design completely eliminates the stress concentration hidden danger of welded assembly structure. The normal service life is ≥36 months, which greatly reduces the equipment downtime rate and spare parts replacement cost. 4. The chassis has a total height of 200mm and a single piece weight of 1803kg. It has extremely high overall rigidity (hot deflection ≤0.2mm). After precision machining, the flatness of the bearing surface is ≤0.3mm / m and the roughness Ra≤3.2μm. The contact area with the steel coil is ≥95%, which provides a near-perfect uniform heat transfer interface and stress foundation for the steel coil. This fundamentally eliminates local overheating, stress concentration and steel coil deformation caused by uneven chassis. 5. This chassis can not only withstand ultra-high temperature annealing of 1150-1200℃, but also serve as a cooling fixture. It uses N2 as a cooling atmosphere to participate in segmented controlled cooling, realizing integrated heat treatment in the furnace. Its maximum long-term operating temperature can reach 1250℃, meeting the stringent requirements of various high-temperature annealing process curves for silicon steel. It can also be recycled and reused, and has economic and process adaptability. Attached Figure Description

[0032] Figure 1 This is a CAE simulation diagram of the bearing stress on the steel coil of the saddle seat according to the present invention; Figure 2 This is a CAE simulation diagram of the saddle structure of the present invention; Figure 3 This is a schematic diagram of the deformation of the saddle in the X direction of the steel coil bearing the saddle in CAE simulation according to the present invention; Figure 4 This is a schematic diagram of the deformation of the saddle in the Y direction of the steel coil bearing the saddle in CAE simulation according to the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Please see Figures 1-4 The present invention provides a technical solution: a method for using a horizontal coil base for annealing steel coils in an annular furnace.

[0035] Saddle stress analysis: (See attached instruction manual) Figure 1 The stress analysis results of the steel coil placed on the saddle can intuitively display the stress magnitude and the location of stress concentration points, and roughly predict the actual deflection direction. Based on this, the structure can be adjusted to make the stress distribution of the saddle more uniform and the stress performance better.

[0036] The X, Y, and Z unidirectional deformation variables are statistical results of the deformation variables in each direction after the saddle is compressed. The smaller the deformation variable, the better the stress stability of the saddle.

[0037] Based on the above analysis, by measuring the numerical changes in the stress concentration region using finite element methods, we can ensure that it is within the allowable stress range of the material. By comparing the deformation data under different working conditions, we can quantitatively evaluate the effectiveness of structural optimization, providing reliable data support for the iterative improvement of the subsequent saddle design, thereby ensuring the safety and reliability of the equipment during long-term operation.

[0038] Example 1: Long-term load-bearing test at 1200℃.

[0039] Material: ZG40Cr25 + trace elements; Process: Precision casting + forging + solution aging + precision machining; Operating conditions: Insulated at 1200℃ for 1000 hours, bearing a load of 15 tons of steel coil.

[0040] The test results showed that the creep deformation rate was 0.12%, the flatness change was no more than 0.15 mm, and no cracks, oxidation peeling, or warping deformation were observed.

[0041] Example 2: Industrial mass production verification.

[0042] Furnace type: Annular inner shroud annealing furnace; Production capacity: 120 steel coils processed per month; Service duration: 18 months.

[0043] Results: No obvious deformation was found in the chassis, the annealing pass rate was not less than 99.7%, and the magnetic property fluctuation did not exceed 3%.

[0044] Example 3: Comparative experiment.

[0045] Experimental group: ZG40Cr25+trace element forged chassis of the present invention; Control group: Traditional ZG40Cr25Ni20 cast chassis.

[0046] The raw material is ZG40Cr25+trace element rare earth reinforced high chromium nickel austenitic heat-resistant cast steel (C0.35-0.45, Cr24.0-26.0). The process parameters are continuous annealing of silicon steel coils, the environment is a nitrogen-hydrogen atmosphere, the maximum temperature is 1250℃, and it is divided into a heating section, a soaking section, a heat preservation section, and a cooling section. N2 is a cooling atmosphere and an inert gas that displaces oxygen, while H2 is a reducing gas that decarburizes and anneals the steel coils.

[0047] Conclusion: The deformation of the experimental group was only 1 / 17 of that of the control group, the bonding area was increased by 35%, and the annealing failure rate was reduced by 94%.

[0048] To quantitatively verify the above conclusions, the key performance indicators of the experimental group (the ZG40Cr25+rare earth / niobium microalloyed forged chassis of this invention) and the control group (traditional ZG40Cr25Ni20 cast chassis) under the same working conditions (1250℃ nitrogen-hydrogen reducing atmosphere, 25 tons of steel coil uniform load, and 100h heat preservation) are compared in Table 1.

[0049] Table 1 - Comparison of Key Performance Indicators for High-Temperature Creep Under Pressure

[0050] The data in Table 1 show that the high-temperature load deformation of the experimental group (0.12 mm) was only 1 / 17 of that of the control group (2.04 mm), which is consistent with the aforementioned conclusion. The contact area between the chassis and the steel coil increased from 70.4% in the control group to 95% (a relative increase of about 35%), the temperature difference of the steel coil cross section decreased from 45℃ to ≤15℃, the high-temperature compression creep rate at 1250℃ decreased from 0.85% / 100h to 0.12% / 100h (about 1 / 7 of the control group), the annealing failure rate decreased from 5.0% to 0.3% (a relative decrease of 94%), and the normal service life was extended from about 12 months to ≥36 months. The above quantitative comparison fully verifies the significant advantages of the horizontal roll base of the present invention in terms of creep resistance, uniform heat transfer, and annealing quality.

[0051] Structural action mechanism and mechanical derivation: Stress analysis: The weight of the steel coil is evenly distributed on the bearing surface, the overall rigidity of the chassis is large, and the hot deflection satisfies f=5GL³ / (384EI)≤0.2mm (1200℃).

[0052] Structural stability mechanism: The 200mm height forms a strong rigid support, with a large bending section modulus. The integral casting has no welds, resulting in a low stress concentration factor. The forging has a high density, comprehensively enhancing tensile, compressive, and shear properties. The elastic modulus decays slowly at high temperatures, resulting in excellent structural geometric stability.

[0053] High-adhesion heat transfer mechanism: The high flatness of the bearing surface significantly reduces the contact thermal resistance, the heat flux density is evenly distributed, there are no hot or cold spots at the bottom of the steel coil, and the annealing structure is uniform and fully reduced.

[0054] High-Temperature Creep Resistance Mechanism Analysis: 1. The high nickel content keeps the austenitic matrix stable, with no phase transformation or embrittlement at high temperatures; 2. High chromium content forms a continuous and dense Cr2O3 oxide film, providing resistance to oxidation and carburization; 3. Niobium precipitation produces NbC and NbN nano-dispersed phases, which pin grain boundaries and inhibit dislocation slip and vacancy diffusion; 4. The creep mechanism changes from grain boundary slip to diffusion creep, and the rate is greatly reduced. It can still maintain high grain boundary strength and long service life at 1200℃.

[0055] Industrial Applicability and Prospects for Industrialization: This invention can be directly adapted to equipment such as silicon steel inner-shroud annealing furnaces, ring furnaces, and high-temperature continuous annealing furnaces for stainless steel coils and alloy coils. It can realize the localization of imported equipment, improve the annealing quality of silicon steel, reduce energy consumption by 5%-10%, and significantly reduce operation and maintenance costs. It can significantly reduce the human, material and time resources that enterprises invest in daily operation and system maintenance, and improve overall operating efficiency and stability.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for using a horizontal coil base for annealing steel coils in an annular furnace, characterized in that: The horizontal roll base is an integral ring-shaped bearing saddle chassis, made of ZG40Cr25 and trace element rare earth reinforced high chromium nickel austenitic heat-resistant cast steel. It is made by integral precision casting, high temperature forging densification and surface finishing. The total height is 200mm, the weight of a single piece is 1803kg, the flatness of the bearing surface is ≤0.3mm / m, and the surface roughness Ra≤3.2μm. The method of use includes the following steps: Step 1, Furnace positioning: Place the chassis horizontally inside the annular furnace, with a levelness of ≤0.2mm / m; Step 2, Steel Coil Loading: Place the silicon steel coil coaxially on the chassis saddle bearing surface in a side-laying manner, so that the center of the steel coil is aligned with the center of the chassis and the force is evenly distributed; Step 3, Inner Cover Sealing: Fasten the inner cover to form a sealed heat treatment cavity, and introduce a protective atmosphere of H2-N2, wherein H2 accounts for 75% of the volume and N2 accounts for 25% of the volume; Step 4, Heating and Annealing: According to the silicon steel process curve, raise the temperature to 1150-1200℃, and perform annealing treatment in sequence through the heating section, soaking section and heat preservation section, and hold for 6-30 hours; Step 5, Uniform Heat Transfer: Utilize the high flatness and high thermal conductivity of the chassis to ensure that the temperature difference of the steel coil is ≤15℃; Step 6, Cooling and Discharging: The material is cooled to a discharge temperature using a segmented controlled cooling method and then discharged. The chassis is recycled and reused.

2. The method of using a horizontal coil base for annealing steel coils in an annular furnace according to claim 1, characterized in that: In step three, the H2-N2 protective atmosphere uses N2 as an inert gas to displace oxygen and H2 as a reducing gas to decarburize and anneal the steel coil.

3. The method of using a horizontal coil base for annealing steel coils in an annular furnace according to claim 1, characterized in that: The heating section, heat soaking section, heat preservation section, and cooling section described in step four constitute a segmented controlled cooling process, in which N2 also serves as the cooling atmosphere.

4. The method of using a horizontal coil base for annealing steel coils in an annular furnace according to claim 1, characterized in that: The chassis exhibits creep deformation ≤0.15% under 1200℃ and 50MPa load conditions for 1000h, and a normal service life ≥36 months.

5. The method of using a horizontal coil base for annealing steel coils in an annular furnace according to claim 1, characterized in that: The chassis has a contact area with the steel coil of ≥95%, and the temperature difference between the steel coil cross sections is ≤15℃.

6. The method of using a horizontal coil base for annealing steel coils in an annular furnace according to claim 1, characterized in that: The chassis material has the following chemical composition by mass fraction: C 0.35-0.45, Cr 24.0-26.0, and is reinforced by microalloying with the addition of niobium and rare earth trace elements.

7. The method of using a horizontal coil base for annealing steel coils in an annular furnace according to claim 1, characterized in that: The manufacturing process of the chassis is as follows: electric arc furnace and ladle refining and smelting; sand casting or investment casting; constant temperature controlled pouring; high temperature forging and compaction; 1180℃ solution treatment and 900℃ aging treatment; surface grinding and precision turning.

8. The method of using a horizontal coil base for annealing steel coils in an annular furnace according to claim 1, characterized in that: The side-mounted load-bearing structure allows the nitrogen-hydrogen mixed protective atmosphere to uniformly and rapidly surround the surface of the steel coil and penetrate into its interior, reducing the temperature difference between the inside and outside of the steel coil and preventing deformation of the steel coil's edges under load.

9. The method of using a horizontal coil base for annealing steel coils in an annular furnace according to claim 1, characterized in that: The chassis has a maximum long-term operating temperature of 1250℃, a creep strength of ≥35MPa at 1200℃, a high-temperature compressive strength of ≥320MPa, and a static oxidation rate of ≤0.08mm / year.

10. The method of using a horizontal coil base for annealing steel coils in an annular furnace according to claim 1, characterized in that: The chassis has stable support at the center, uniform force distribution on the outer ring, uniform wall thickness transition, no stress concentration, excellent overall rigidity, and hot deflection f=5GL³ / (384EI)≤0.2mm.

Images