Production method of high-grade non-oriented silicon steel hot-rolled strip steel

Abstract

The invention relates to a production method of high-grade non-oriented silicon steel hot-rolled strip steel, and belongs to the technical field of steel preparation. The method comprises the following steps: carrying out heating treatment on a non-oriented silicon steel continuous casting sheet billet containing specific alloy components, and controlling the tapping temperature of the heating treatment to be a set tapping temperature; carrying out rough rolling on the heated non-oriented silicon steel continuous casting sheet billet to obtain an intermediate billet; the intermediate billet is subjected to finish rolling, and hot-rolled strip steel is obtained; and the hot-rolled strip steel is subjected to laminar cooling, coiling, heat preservation and edge cutting, and the high-grade non-oriented silicon steel hot-rolled strip steel is obtained. Key process parameters of each hot rolling process are accurately controlled, and batch stable production of the high-grade non-oriented silicon steel with high silicon and high nickel alloy components is realized. According to the method, the edge qualification rate and the yield are increased, the harsh requirements of users for the material performance, the size and the strength are met, and key material support is provided for strategic emerging industries such as new energy automobiles and unmanned aerial vehicles.

Description

Technical Field

[0001] This application relates to the field of steel preparation technology, and in particular to a method for producing high-grade non-oriented silicon steel hot-rolled strip. Background Technology

[0002] With the transformation of the global energy structure and the growing acceptance of green and low-carbon concepts, strategic emerging industries such as new energy vehicles and drones have ushered in unprecedented development opportunities. These industries have increasingly stringent requirements for motor performance, specifically in the pursuit of high power density, long endurance, and high-speed characteristics. As one of the core materials for motors, non-oriented silicon steel directly affects the overall efficiency and lifespan of the motor. Currently, the demand for non-oriented silicon steel in motors for new energy vehicles and drones exhibits significant characteristics such as low iron loss, high magnetic induction, and high strength. Specifically, the finished silicon steel must meet a magnetic induction greater than 1.61T to ensure sufficient electromagnetic conversion capability during efficient motor operation; simultaneously, high-frequency iron loss must be controlled within the range of less than 12W / kg to reduce energy loss during conversion and improve motor efficiency; furthermore, the material must possess high strength characteristics, with a yield strength greater than 470Mpa, to cope with the enormous mechanical stress generated by the motor during high-speed operation.

[0003] To meet the aforementioned performance requirements, the composition design of non-oriented silicon steel has undergone a fundamental change. The silicon content has exceeded the upper limit of current mass production, and a higher proportion of alloying elements, such as nickel, needs to be added to further enhance the material's magnetic and mechanical properties. However, this high-silicon, high-nickel alloy composition of non-oriented silicon steel faces significant technical challenges in the production of hot-rolled raw material coils. Due to the complex composition, the quality sealing rate during hot rolling is over 40%, and the edge cracking rate during trimming is over 90%. This severely restricts the product yield and production efficiency, becoming a bottleneck hindering the realization of high-grade non-oriented silicon steel products for new energy vehicles and drones.

[0004] Furthermore, the market has placed more stringent requirements on the specifications of non-oriented silicon steel. Products must possess extremely thin and wide dimensions to meet the design demands for miniaturized and lightweight motors. However, existing technologies are not yet mature enough to support the mass production of high-grade non-oriented silicon steel with high silicon and high nickel alloy compositions. This has resulted in these products remaining in the research and development and small-batch trial production stages for a long time, failing to meet the urgent market demand. Summary of the Invention

[0005] This application provides a method for producing hot-rolled strip of high-grade non-oriented silicon steel to solve the following technical problem: how to solve the edge cracking problem encountered in the hot rolling process of high-grade non-oriented silicon steel with high silicon and high nickel content and thin and wide specifications. This application provides a method for producing high-grade non-oriented silicon steel hot-rolled strip, the method comprising: The non-oriented silicon steel continuous casting slab containing a specific alloy composition is heated and the furnace exit temperature of the heated treatment is controlled to be the set furnace exit temperature. The heated non-oriented silicon steel continuous casting slab is rough rolled to obtain an intermediate slab. The intermediate billet is then precision rolled to obtain hot-rolled strip steel; The hot-rolled strip is subjected to laminar flow cooling, coiling, heat preservation and edge trimming to obtain high-grade non-oriented silicon steel hot-rolled strip. The specific alloy composition, by mass fraction, includes: Si: 3.3%–3.6%, Mn: 0.4%–0.6%, Ni: 2.0%–2.4%, and Als: 0.5%–0.9%.

[0006] Optionally, in the heat treatment, the furnace entry temperature of the non-oriented silicon steel continuous casting slab is ≥300℃, and the furnace exit temperature of the non-oriented silicon steel continuous casting slab is ≤1130℃.

[0007] Optionally, the roughing mill uses a 1+5 rolling mode, the roughing mill reduction rate is ≥85%, the roughing mill finishing temperature is ≥970℃, and the total width reduction per pass is ≥110mm.

[0008] Optionally, the difference between the final rolling temperature of the roughing mill and the final rolling temperature of the finishing mill is ≤100℃.

[0009] Optionally, the temperature drop during the finishing rolling process is ≤70℃.

[0010] Optionally, the vertical roll mill before the finishing mill adopts a constant pressure control mode, and the rolling force of the vertical roll mill before the finishing mill is ≥200KN.

[0011] Optionally, the finishing rolling is a combination of head-limited speed rolling and final rolling with a temperature gauge loaded for 10 to 100 meters before speed increase, and the final rolling temperature of the finishing rolling is ≥850℃.

[0012] Optionally, the threading speed of the head in the head-limited rolling is 10 m / s to 11 m / s, and the acceleration of the speed-increasing rolling is ≤0.2 m / s². 2 .

[0013] Optionally, the winding temperature is 500℃~600℃.

[0014] Optionally, the laminar flow cooling adopts a front-end intensive cooling mode.

[0015] Optionally, the temperature of the cut edge is 120℃~150℃.

[0016] Optionally, the thickness of the high-grade non-oriented silicon steel hot-rolled strip is 2.0 mm to 2.2 mm.

[0017] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for producing high-grade non-oriented silicon steel hot-rolled strip. The method includes: heating a non-oriented silicon steel continuous casting slab containing a specific alloy composition, and controlling the furnace exit temperature of the heating treatment to a set exit temperature; rough rolling the heated non-oriented silicon steel continuous casting slab to obtain an intermediate slab; finish rolling the intermediate slab to obtain hot-rolled strip; and subjecting the hot-rolled strip to laminar flow cooling, coiling, heat preservation, and edge trimming to obtain high-grade non-oriented silicon steel hot-rolled strip. The specific alloy composition lays the plasticity foundation through the synergistic effect of multiple elements. The heating process reduces the temperature difference between the inside and outside of the slab by controlling the furnace entry, avoiding micro-cracks at the edges and corners caused by thermal shock during heating. Controlling the furnace exit temperature suppresses excessive segregation of Si and Ni at grain boundaries and precipitation of brittle Fe3Si phases at high temperatures, ensuring uniform overall plasticity of the slab. The 1+5 rolling mode and high pressure reduction in the roughing process break up the coarse grains in the cast state through multiple passes of deformation, promoting dynamic recrystallization and forming a uniform and fine austenitic structure, thus reducing the resistance to subsequent deformation. The final rolling temperature ensures that the roughing is completed in the single-phase austenitic region (avoiding the formation of the brittle α-Fe phase). The total width reduction in the roughing process is linked to the constant pressure of the vertical roll mill before the finishing mill. The roughing process corrects edge defects of the slab through multiple passes of width reduction, and the vertical roll mill before the finishing mill further eliminates edge deviations with constant pressure and active side pressure. The finishing process combines head-limited speed rolling and speed-up rolling under load by the final rolling temperature instrument to control the temperature drop in the finishing area, while ensuring that the strip head is straight and has a good shape, avoiding the sudden drop in plasticity, edge cracks, and poor shape caused by excessive temperature drop in the intermediate slab. Intensive cooling and controlled coiling temperature in the initial stage allow the strip to quickly pass through the brittle zone, inhibiting abnormal ferrite grain growth and precipitation of silicon-nickel intermetallic compounds. After heat treatment, shearing occurs within the "ductile-brittle transition range," where the strip edge exhibits optimal plasticity, avoiding edge burrs and tearing caused by low-temperature embrittlement or high-temperature softening. By ensuring the strip remains in a state of "low brittleness and high plasticity" throughout heating, rolling, cooling, and shearing, the problem of edge cracking caused by high silicon and high nickel content is fundamentally solved, enabling stable production of thin, wide, high-grade non-oriented silicon steel. Attached Figure Description The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

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

[0019] Figure 1 A schematic flow diagram of a production method for high-grade non-oriented silicon steel hot-rolled strip provided in this application embodiment; Figure 2 The surface quality diagram provided for Comparative Example 1 of this application; Figure 3 A surface quality diagram provided for Embodiment 1 of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "including" and "contains" as used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0022] Figure 1 This is a schematic flowchart illustrating a production method for high-grade non-oriented silicon steel hot-rolled strip, provided in an embodiment of this application.

[0023] Please see Figure 1 This application provides a method for producing high-grade non-oriented silicon steel hot-rolled strip, the method comprising: S1. Heat-treat a non-oriented silicon steel continuous casting slab containing a specific alloy composition, and control the furnace exit temperature of the heat treatment to the set furnace exit temperature. In some embodiments, the specific alloy composition, by mass fraction, includes: Si: 3.3%–3.6%, Mn: 0.4%–0.6%, Ni: 2.0%–2.4%, and Als: 0.5%–0.9%.

[0024] In some embodiments, during the heat treatment, the furnace entry temperature of the non-oriented silicon steel continuous casting slab is ≥300℃, and the furnace exit temperature of the non-oriented silicon steel continuous casting slab is ≤1130℃.

[0025] If the furnace entry temperature of non-oriented silicon steel continuously cast slabs is below 300℃, the large temperature difference between the inside and outside will cause thermal stress concentration, leading to microcracks inside the slab (especially at the edges and corners). During subsequent rolling, crack propagation will exacerbate the incidence of edge cracks. Controlling the furnace entry temperature to ≥300℃ can reduce the heating rate gradient within the furnace, minimizing structural damage caused by thermal shock and providing a complete billet foundation for subsequent rough rolling (reduction rate ≥85%). Furthermore, a furnace entry temperature ≥300℃ can shorten the "heating-soaking" time of the slab in the furnace, reducing the segregation of alloying elements such as silicon and nickel at grain boundaries and inhibiting the precipitation of high-temperature brittle phases (such as Fe3Si). Combined with a final rolling temperature of ≥970℃ for rough rolling, this achieves uniform microstructure control throughout the entire process. Ensuring this furnace entry temperature can be achieved through methods such as direct loading of the continuously cast slab after production, slow cooling in stacks, and insulation in insulation pits. For example, the furnace entry temperature of non-oriented silicon steel continuous casting slabs can be 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, etc.

[0026] Controlling the tapping temperature to ≤1130℃ is crucial to preventing the precipitation of brittle phases at high temperatures and excessive austenite grain growth. This process window can be achieved through precise control of the furnace gas temperature and in-furnace time in the preheating, first-stage, second-stage, and soaking stages. For example, the tapping temperature of non-oriented silicon steel continuously cast slabs can be 1115℃, 1118℃, 1121℃, 1124℃, 1127℃, 1130℃, etc.

[0027] S2. The heated non-oriented silicon steel continuous casting slab is rough rolled to obtain an intermediate slab; In some embodiments, the roughing rolls adopt a 1+5 rolling mode, the roughing reduction rate is ≥85%, the final rolling temperature of the roughing rolls is ≥970℃, and the total width reduction per pass of the roughing rolls is ≥110mm.

[0028] The roughing mill uses a 1+5 rolling pattern, meaning one pass in the R1 roughing mill and five passes in the R2 roughing mill. The high-rigidity R1 stand achieves initial large deformation, rapidly reducing the slab thickness and breaking down coarse surface grains, laying the foundation for the multi-pass refining in R2. R2, through multiple passes with small reductions, controls deformation uniformity, reduces deformation differences between the edges and center, lowers transverse thickness variations, and avoids edge cracks caused by stress concentration. A roughing reduction rate ≥85% can break down the as-cast structure, promote dynamic recrystallization, and form fine, uniform austenite grains, providing a good microstructure for subsequent cooling and cold rolling processes. For example, the roughing reduction rate can be 85%, 86%, 87%, 88%, 89%, 90%, etc. The final rolling temperature of the roughing roll is ≥970℃. This temperature ensures that the austenite does not undergo phase transformation (avoiding the formation of the brittle α-Fe phase), the strip has good plasticity, and can withstand further deformation in subsequent finishing rolling, avoiding edge cracks caused by low-temperature rolling. For example, the final rolling temperature of the roughing roll can be 970℃, 975℃, 980℃, 985℃, 990℃, etc.

[0029] The total width reduction per pass refers to the sum of the slab width reductions achieved through vertical roll width reduction operations in the roughing rolling process. In this embodiment, the roughing rolling vertical rolls employ a 1+3 pass width reduction pattern (i.e., E1 vertical roll width reduction for 1 pass, E2 vertical roll width reduction for 3 passes), and the total width reduction after summing the width reduction amounts from each pass is not less than 110mm. Its function is to control slab width fluctuations through multi-pass width reduction distribution, correct irregular edge shapes of the slab, provide uniformly wide slabs for subsequent finishing rolling and trimming processes, reduce transverse thickness differences and edge stress concentration, and lower the risk of edge cracking. For example, the total width reduction per pass in roughing rolling can be 110mm, 120mm, 130mm, 140mm, 150mm, etc.

[0030] S3. The intermediate billet is precision rolled to obtain hot-rolled strip steel; In some embodiments, the temperature drop during the finishing rolling process is ≤70°C.

[0031] The temperature drop during the finishing rolling process should be ≤70℃, meaning that the temperature decrease of the strip from entering the finishing mill to the end of the finishing rolling process must be controlled within 70℃. If the temperature drop exceeds 70℃, the strip temperature may drop below 850℃ (the lower limit of the rolling end temperature) in the later stages of finishing rolling, leading to a sharp drop in plasticity, a surge in rolling force, and causing edge cracks and poor strip shape (such as waviness).

[0032] In some embodiments, the vertical roll mill before the finishing mill of the finishing mill adopts a constant pressure control mode, and the rolling force of the vertical roll mill before the finishing mill is ≥200KN.

[0033] Constant pressure control mode is a control method that maintains a constant rolling pressure during the rolling process. This control mode ensures that the pressure applied by the rolls to the workpiece remains constant throughout the entire rolling process. This effectively reduces stress concentration at the edges of the workpiece caused by uneven pressure, thereby reducing the risk of edge cracking. Furthermore, under constant pressure, the deformation behavior of the workpiece is more uniform and controllable, which helps reduce cracking caused by excessive local deformation and improves the overall quality of the workpiece. When implementing constant pressure control mode, the rolling force needs to be set. Setting the rolling force too high may result in an excessively thin workpiece or even breakage, while setting it too low may fail to achieve the desired rolling effect. In this embodiment, the rolling force of the vertical roll mill before the finishing mill is ≥200KN. For example, the rolling force of the vertical roll mill before the finishing mill can be 200KN, 202KN, 204KN, 206KN, 208KN, 210KN, etc.

[0034] In some embodiments, the finishing rolling is a combination of head-limited speed rolling and final rolling with a temperature gauge loaded for 10 to 100 meters before speed increase, and the final rolling temperature of the finishing rolling is ≥850℃.

[0035] Finishing rolling is divided into two stages: the initial stage uses head-limited speed rolling, and after the strip head has passed through a length range of 10 to 100 meters and the temperature has stabilized, speed-up rolling (acceleration ≤ 0.2 m / s²) is then carried out. 2 Head-limited speed rolling is a speed-limiting measure implemented at the initial stage of strip rolling to ensure the strip can smoothly pass through the stands of the finishing mill and avoid problems such as floating and folding caused by excessive speed. Finishing temperature instruments (such as infrared thermometers) are used to monitor the temperature changes of the strip in real time during the rolling process, ensuring that the finishing temperature is controlled within the allowable fluctuation range. Speed-increasing rolling can significantly increase the rolling speed of the strip and make the finishing temperature control of the strip more precise.

[0036] Final rolling temperature is an extremely important parameter in the production of hot-rolled strip steel, as it directly affects the microstructure, mechanical properties, and final quality of the strip steel. In the embodiments of this application, the final rolling temperature of the finishing mill is ≥850℃, with an average of 890℃.

[0037] In some embodiments, the threading speed of the head in the head-limited rolling is 10 m / s to 11 m / s, and the acceleration of the speed-increasing rolling is ≤0.2 m / s². 2 .

[0038] The head threading speed specifically refers to the initial rolling speed of the strip head as it enters the finishing mill. A head threading speed of 10 m / s to 11 m / s is used to ensure that the temperature drop in the finishing rolling zone does not exceed 70°C. This speed also prevents strip warping caused by sudden tension changes at the strip head, ensuring a straight and even strip shape. For example, the head threading speed for head-limited rolling can be 10 m / s, 10.2 m / s, 10.4 m / s, 10.6 m / s, 10.8 m / s, 11 m / s, etc. After the initial threading, the speed increases to 0.2 m / s. 2 The acceleration is gradually increased, forming a composite rolling mode of "low-speed threading + dynamic speed increase", which can take into account both temperature control accuracy and rolling efficiency.

[0039] In some embodiments, the difference between the final rolling temperature of the roughing mill and the final rolling temperature of the finishing mill is ≤100°C.

[0040] The requirement that the temperature difference between the final rolling temperature of roughing and finishing rolling be ≤100℃ refers to the temperature control requirement for the entire process of strip steel from roughing to finishing. This requirement stipulates that the temperature difference between the strip steel at the end of roughing and finishing rolling must be ≤100℃. This control can be achieved by using an insulation cover and limiting the temperature drop of the intermediate billet on the intermediate roller table between roughing and finishing rolling to no more than 30℃. In the hot rolling process of silicon steel, the intermediate billet formed after roughing needs to be transported to the finishing mill via an intermediate roller table. If the temperature drop of the intermediate billet is too large at this time, it will lead to a decrease in rolling stability and abnormal material structure. By using an insulation cover, the heat loss of the intermediate billet during transportation on the intermediate roller table can be effectively slowed down. The insulation cover, by blocking radiative heat dissipation and air convection, can strictly control the surface temperature drop of the intermediate billet to within 30℃. By precisely controlling the temperature drop, the thermoplasticity and recrystallization ability of the material can be guaranteed, and edge defects (such as edge cracks) caused by excessive temperature gradients can be avoided. At the same time, the uniformity of rolling force in the finishing rolling stage can be ensured, and the shape and dimensional accuracy of the plate can be improved.

[0041] S4. The hot-rolled strip is subjected to laminar flow cooling, coiling, heat preservation and edge trimming to obtain high-grade non-oriented silicon steel hot-rolled strip. In some implementations, the laminar flow cooling employs a front-end intensive cooling mode.

[0042] The front-end intensive cooling mode refers to prioritizing the activation of the front-end cooling manifold near the finishing mill exit during the laminar flow cooling process. By concentrating the cooling capacity of the initial high-temperature section after finishing rolling, the strip steel is rapidly cooled from the finishing rolling end temperature to the target coiling temperature. This mode avoids excessively long residence time of the strip steel in the high-temperature section, which can lead to coarse grains or brittle phase precipitation, effectively controlling the uniformity of the microstructure and reducing the risk of edge cracking in subsequent edge trimming processes.

[0043] In this embodiment, each cooling manifold has 4 pipes at the top and 4 at the bottom open. Laminar flow cooling manifolds are typically divided into upper manifolds (above the strip) and lower manifolds (below the strip). "4 pipes at the top and 4 at the bottom open" means that in each cooling unit, 4 manifolds are open at the top and 4 at the bottom, achieving the following effect through symmetrical strong cooling from top to bottom: Cooling uniformity: The same number of manifolds are opened simultaneously on the upper and lower surfaces to avoid excessive temperature difference between the upper and lower surfaces of the strip due to uneven cooling, and to reduce transverse stress concentration. Cooling efficiency: The dense opening of four manifolds at the top and bottom provides sufficient cooling intensity, ensuring that the strip steel quickly reaches the target coiling temperature before entering the coiler, thus avoiding coarse structure caused by high-temperature coiling.

[0044] In some embodiments, the winding temperature is 500°C to 600°C.

[0045] If the coiling temperature exceeds 600℃, the prolonged residence time of the strip at high temperatures can easily lead to abnormal growth of ferrite grains, reducing magnetic induction and increasing iron loss. If the coiling temperature is below 500℃, the strip hardness may increase sharply, exceeding the yield strength limit of the cold rolling process, resulting in excessive cold rolling force and loss of strip shape control. Furthermore, in the embodiments of this application, coiling temperatures above 600℃ easily lead to the precipitation of intermetallic compounds of silicon and nickel (such as Fe3Si), causing strip embrittlement and exacerbating the risk of edge cracking in subsequent trimming processes. For example, the coiling temperature can be 500℃, 520℃, 540℃, 560℃, 580℃, 600℃, etc.

[0046] After the strip is unwound from the production line, it is immediately transferred to an insulation pit for slow cooling, allowing the temperature to gradually drop to the edge-cutting temperature. This reduces the accumulation of internal stress caused by rapid cooling and lowers the incidence of edge cracks during the edge-cutting process.

[0047] In some embodiments, the temperature of the cut edge is 120°C to 150°C.

[0048] The temperature range of 120℃ to 150℃ is the "ductile-brittle transition temperature range" for the non-oriented silicon steel in this application embodiment. At this temperature, the strip edge exhibits optimal plasticity, preventing embrittlement at low temperatures (<120℃) or softening at high temperatures (>150℃) that could lead to burrs and tearing at the sheared edges. This application embodiment can use a conventional disc shear to cut the edges. For example, the cutting temperature can be 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, etc.

[0049] In some embodiments, the thickness of the high-grade non-oriented silicon steel hot-rolled strip is 2.0 mm to 2.2 mm.

[0050] This application provides a method for producing high-grade non-oriented silicon steel hot-rolled strip. By precisely controlling the key parameters and process steps in the hot rolling process, it effectively solves the technical problems encountered in the hot rolling production of high-grade non-oriented silicon steel with high silicon and high nickel content in thin and wide specifications (2.0mm~2.2mm)*(1150mm~1320mm), such as edge cracking and low yield, and achieves stable batch supply and meets the requirements of high-end performance.

[0051] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0052] Please refer to Table 1 for the preparation process parameters of a high-grade non-oriented silicon steel hot-rolled strip.

[0053] Table 1

[0054] The quality of the hot-rolled edge-trimmed coils of high-grade non-oriented silicon steel obtained in the examples and comparative examples was evaluated, and the evaluation results are shown in Table 2.

[0055] Table 2

[0056] As can be seen from the data in Table 1-2, the process parameters of the embodiment are within the required range of the present invention, and the edge quality of the obtained silicon steel is better.

[0057] Appendix Figure 2-3 Detailed explanation: Figure 2 The image shows the surface quality of Comparative Example 1 of this application. As can be seen from the image, cracks appear in the band.

[0058] Figure 3 This is a surface quality diagram provided for Embodiment 1 of this application. As can be seen from the diagram, the edge quality of the hot-rolled strip in Embodiment 1 is relatively good.

[0059] Furthermore, one or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: Improved edge pass rate: The process optimization measures provided in this embodiment of the invention significantly reduce the occurrence rate of edge cracks.

[0060] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for producing high-grade non-oriented silicon steel hot-rolled strip, the method comprising: The non-oriented silicon steel continuous casting slab containing a specific alloy composition is heated and the furnace exit temperature of the heated treatment is controlled to be the set furnace exit temperature. The heated non-oriented silicon steel continuous casting slab is rough rolled to obtain an intermediate slab. The intermediate billet is then precision rolled to obtain hot-rolled strip steel; The hot-rolled strip is subjected to laminar flow cooling, coiling, heat preservation and edge trimming to obtain high-grade non-oriented silicon steel hot-rolled strip. The specific alloy composition, by mass fraction Includes: Si: 3.3%–3.6%, Mn: 0.4%–0.6%, Ni: 2.0%–2.4%, Als: 0.5%–0.9%.

2. The method according to claim 1, characterized in that, In the heat treatment, the furnace entry temperature of the non-oriented silicon steel continuous casting slab is ≥300℃, and the furnace exit temperature of the non-oriented silicon steel continuous casting slab is ≤1130℃.

3. The method according to claim 1, characterized in that, The roughing mill uses a 1+5 rolling mode, the reduction rate of the roughing mill is ≥85%, the final rolling temperature of the roughing mill is ≥970℃, and the total width reduction per pass of the roughing mill is ≥110mm.

4. The method according to claim 1, characterized in that, The difference between the final rolling temperature of the roughing mill and the final rolling temperature of the finishing mill is ≤100℃.

5. The method according to claim 1, characterized in that, The temperature drop during the finishing rolling process is ≤70℃; and / or, The vertical roll mill before the finishing mill adopts a constant pressure control mode, and the rolling force of the vertical roll mill before the finishing mill is ≥200KN.

6. The method according to claim 1, characterized in that, The finishing rolling is a combination of head-limited speed rolling and final rolling with a temperature gauge loaded for 10 to 100 meters before speed increase, and the final rolling temperature of the finishing rolling is ≥850℃.

7. The method according to claim 6, characterized in that, The threading speed of the head in the head-limited rolling process is 10 m / s to 11 m / s, and the acceleration of the speed-increasing rolling process is ≤0.2 m / s². 2 .

8. The method according to claim 1, characterized in that, The winding temperature is 500℃~600℃; and / or, The laminar flow cooling adopts a front-end intensive cooling mode.

9. The method according to claim 1, characterized in that, The temperature of the cut edge is 120℃~150℃.

10. The method according to claim 1, characterized in that, The thickness of the high-grade non-oriented silicon steel hot-rolled strip is 2.0mm to 2.2mm.

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