Method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel

Abstract

The present application relates to a kind of control methods of hot-rolled non-oriented silicon steel section shape, including S1, rolling plan arrangement;S2, the adjustment of rolling process;S3, the linkage of bending roll and roll and the optimization of tension;S4, strip steel crown control;S5, the opening degree control of finishing mill vertical roll and guide ruler;The present application can effectively improve the size control precision of hot-rolled non-oriented silicon steel product, in thickness, crown, wedge and transverse thickness difference, to meet the raw material demand of downstream cold rolling process, to provide the best hot-rolled raw material section shape guarantee for improving the same plate difference index of cold-rolled silicon steel product.Thereby certain economic benefits are generated in reducing the amount of trimming, improving comprehensive yield.Raising the overall quality level of product, meet the high standard demand of terminal user pressing sheet processing.

Description

Technical Field

[0001] This invention relates to the field of non-oriented silicon steel production technology, and in particular to a method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel. Background Technology

[0002] Cold-rolled non-oriented silicon steel, as an important metallic material, is widely used in motor manufacturing and other applications. In motor manufacturing, silicon steel is typically processed as a single sheet, and then stacked to form the core. The precision of cold-rolled non-oriented silicon steel sheets requires the guarantee of excellent raw materials from hot rolling, especially in terms of sheet crown, wedge shape, and transverse thickness variation.

[0003] Hot-rolled non-oriented silicon steel primarily controls the strip's crown and wedge shape. This is achieved by controlling metal flow through the deformation of the strip during rolling, with the crown and wedge shape indicators fed back by a multi-functional instrument at the finishing mill exit. The overall stability of the coil's crown and wedge shape determines the production stability of the cold rolling process. The cross-sectional shape of hot-rolled products is completely inherited from the cold rolling process. Products with poor cross-sections in cold-rolled base material show little improvement after cold rolling, and may even experience breakage or scrap. Edge thinning is also an important cross-sectional quality indicator. The amount of edge thinning directly affects the size of the cutting loss and is closely related to the yield. The amount of edge cutting loss in silicon steel sheets is positively correlated with the yield; the less cutting loss, the higher the yield. In the steelmaking process, strict control over the cross-sectional shape of the steel slab, including its wedge shape, side bending, and temperature difference between the two sides and the head and tail, significantly impacts the shape of the subsequent silicon steel sheets. In the hot rolling roughing stage, slab shape control is crucial, affecting the crown and wedge shape in subsequent processes. Straightness and absence of side bending are mandatory, and the wedge shape of intermediate slabs must also meet standards. Finishing rolling is the final process for controlling the product's cross-sectional shape and is a core process for ensuring quality indicators. It involves pressure reduction and leveling control, strip centering rolling, work roll profile design, work roll shifting, looper tension setting, bending force control, and crown self-learning.

[0004] The cross-sectional shape of hot-rolled silicon steel products is completely inherited from the cold rolling process. Currently, the hit rate of hot-rolled silicon steel products with a convexity of 20μ±10 is less than 74%; the hit rate of wedge shape within ±15μ is less than 65%; and the pass rate of silicon steel products with a thickness difference of less than 8μm is less than 50%, which is significantly lower than the pass rate of more than 85% of similar steel companies. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel, which can meet the raw material requirements of downstream cold rolling processes in terms of thickness, crown, wedge shape, and transverse thickness difference, and provide optimal hot-rolled raw material cross-sectional shape guarantee for improving the same-plate difference index of cold-rolled silicon steel products.

[0006] The technical solution adopted in this invention is as follows:

[0007] The present invention proposes a method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel, comprising the following steps:

[0008] S1. Rolling schedule arrangement; the hardness of the transition material during the silicon steel rolling cycle must be close to that of silicon steel, and the hot roll material stage must ensure the full formation of the oxide film on the rolls; at the same time, the rolling mileage of the work rolls within a rolling cycle should be controlled within a reasonable range to prevent local high points from appearing on the cross-section.

[0009] S2. Adjustment of rolling process; The heating temperature of the steel must reach the standard temperature difference range. At the same time, for long-term planned shutdown of rolling, space should be reserved for the furnace head steel to prevent transverse temperature difference of slab caused by poor sealing of the heating furnace.

[0010] S3, the linkage and tension optimization of bending and shifting rolls; the downstream stand adopts a special work roll type, namely a work roll with slow edge descent, thereby realizing the edge descent control of strip steel, laying a good cross-sectional foundation for the same plate difference of cold rolled finished products;

[0011] S4. Strip crown control; automatically optimizes itself by increasing the number of self-learning crown counts.

[0012] S5. Control of the opening of the vertical rolls and guides in the finishing mill: First, the opening of the vertical rolls before entering the finishing mill is oscillated according to the side pressure; In addition, the roughing mill control process requires adjusting the roll gap balance of each pass of the roughing mill stand based on the actual measurement feedback of the previous coil.

[0013] S6, Loop unit tension control.

[0014] Furthermore, in step S1, the number of hot-roll material pieces before rolling non-oriented silicon steel is controlled within 10-15 pieces or 15km; the coiling time before and after finishing rolling of the four steel pieces before changing rolls is controlled at more than 30 seconds, which is conducive to the formation of oxide film on the rolls; during the rolling cycle, the diameter of the work rolls in each stand of finishing rolling decreases from F1 to F7 in each stand; the hardness of the hot-roll material is higher than that of the silicon steel being rolled, and the thickness is required to transition from 4.7mm to 2.7mm; the width of the hot-roll material is greater than the width of the non-oriented silicon steel, and reverse width rolling is not allowed.

[0015] Furthermore, in step S2, during the high-temperature heating process of the slab, the transverse temperature difference is controlled within 30°C, the head and tail temperatures are more than 20°C higher than the body temperature, the inter-furnace temperature difference is controlled within 30°C, and the steel firing temperature must reach the standard temperature difference range; during the rough rolling process, R1 rolling is performed in 3 passes and R2 rolling in 3 passes, the thickness of the intermediate slab is controlled to be more than 40mm, the wedge shape is less than 0.2mm, and the width reduction of the slab is less than 40mm; at the same time, the overall sickle shape of the intermediate slab is controlled, and during the rolling process, the offset between the rolling center line and the intermediate slab center line does not exceed 20mm; during the transition material period before the production of non-oriented silicon steel, leveling control is performed to adjust the strip wedge shape within the standard range before it is coiled in the hot coil box.

[0016] Furthermore, during the seven-stand continuous rolling process, the reduction rate of F1 to F3 is not less than 42%, 25% ≤ F4 to F6 < 38%, and F7 < 20%; F1 to F4 are CVC rolls, and F5 to F7 are special work rolls with crown values ​​controlled within -150μm; the seven-stand mill is equipped with a positive bending roll force adjustment function, with a setting range of 50 to 80T, and decreasing with each stand.

[0017] Furthermore, in step S3, the bending roll force of each stand is dynamically calculated by learning from the calculation of the roll crown, thereby obtaining good head and tail plate shape quality; the bending roll setting calculation formula is:

[0018]

[0019] In the formula, B f Set the calculated value for the bending roller force; C m For the mechanical crown of the strip; R f Set the rolling force value; C WC The composite roll shape in the middle of the work roll body; C WE The overall roll shape of the working roll body; C BC To support the overall roll shape in the middle of the roll body; C BE To support the overall roll profile of the roll body; C WR The initial roll shape of the work roll; k BF k is the influence coefficient of the bending roller force. WC k is the influence coefficient of the roll shape in the middle of the work roll. WE k is the influence coefficient of the roll shape at the edge of the work roll. BC Support roller center roll shape influence coefficient; k BE To support the influence coefficient of roll edge shape; k CWR k is the influence coefficient of the initial roll shape of the work roll. CST k is a constant coefficient. RF This is the rolling force influence coefficient.

[0020] Furthermore, in step S4, the convexity self-learning algorithm is as follows:

[0021]

[0022] In the formula: ΔC c (i+1) is the self-learning value of the convexity of the (i+1)th strip; ΔC c (i) represents the self-learning value of the convexity of the i-th strip; k is the adjustment amount of the model coefficient calculated based on the measured value of the crown of the i-th strip; c This is the convexity self-learning gain coefficient.

[0023] Furthermore, step S5 specifically includes: in order to control strip deviation, the opening of the vertical roll before entering the finishing mill is first oscillated according to the side pressure; the opening of the finishing mill guide is set to compensate by increasing the R2 exit width by 5mm; the wedge shape of the intermediate billet of the R2 incoming material in the roughing mill is controlled within 0.05mm, and the roll gap balance of each pass of the roughing mill stand is carefully adjusted according to the actual measurement feedback of the previous coil of steel.

[0024] Furthermore, in step S6, the unit tension of the looper is set within the range of 6–14 N / mm. 2 .

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] This invention achieves excellent cross-sectional dimensional accuracy with crown and wedge shape less than 25μm by standardizing the planned layout within a rolling cycle, optimizing and controlling the plate shape in the roughing rolling area, and optimizing the control of equipment such as rolls and guides in the finishing rolling area. The finishing rolling utilizes control methods such as leveling control, AGC adjustment, and tension optimization. This avoids the phenomenon of large fluctuations in plate crown throughout the coil and wedge shape index exceeding the plate crown value. It solves the problem of mismatched cross-sections of cold-rolled non-oriented silicon steel base material. The rolling yield of non-oriented silicon steel in the downstream cold rolling mill is increased to over 95%, which is better than the existing level. Attached Figure Description

[0027] Figure 1 Here is a flow chart of the existing hot rolling production process;

[0028] Figure 2 This is a schematic diagram comparing F5-F7 roll types with conventional roll types;

[0029] Figure 3 This is a schematic diagram of an asynchronous sinusoidal roller shifting strategy;

[0030] Figure 4 A schematic diagram showing the comparison of hot-rolled wedge curves and corresponding deviation values;

[0031] Figure 5 This is a schematic diagram of the plate convexity curve;

[0032] Figure 6 This is a schematic diagram of the wedge control curve. Detailed Implementation

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] The main production process of non-oriented silicon steel is smelting → continuous casting → hot rolling → pickling → cold rolling → continuous annealing → coating → rewinding. The equipment for hot rolling of non-oriented silicon steel includes... Figure 1 As shown, the system consists of three walking beam furnaces, pre-rolling descaling, R1 two-roll roughing mill, R2 four-roll roughing mill, hot coil box, flying shear, fine descaling, F1-F7 finishing mill, laminar flow cooling, and coiling machine; where HF1-HF3: three furnaces; HSB: roughing mill descaling; R1D: pre-R1 descaling; R2D: pre-R2 descaling; E1, E2: pre-roughing mill vertical rolls; RT: pre-roughing mill pyrometer; R1, R2: two roughing mill stands; CB: hot coil box; CS: flying shear; FET: finishing mill inlet pyrometer; FSB: finishing mill descaling; F1E: pre-finishing mill vertical rolls; F1-F7: seven finishing mill stands; FDT: finishing mill outlet pyrometer; LCS: laminar flow cooling mechanism; CT: pre-coiling pyrometer; DC1-DC3: three underground coiling machines.

[0035] Precise control of the entire hot rolling process is crucial for improving the overall quality of cold-rolled silicon steel products.

[0036] See appendix Figure 2-6 The specific implementation steps of the method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel proposed in this invention are as follows:

[0037] S1. Rolling schedule arrangement; the hardness of the transition material during the silicon steel rolling cycle must be close to that of silicon steel, and the hot roll material stage must ensure the full formation of the oxide film on the rolls; at the same time, the rolling mileage of the work rolls within a rolling cycle should be controlled within a reasonable range to prevent local high points from appearing on the cross-section.

[0038] During hot rolling production, to ensure the surface quality of the strip and the dimensional accuracy of the product, multiple experiments and adjustments were conducted to determine that within each work roll cycle, after transitioning from ordinary steel hot rolls to non-oriented silicon steel, silicon steel must be rolled continuously, and cross-rolling with ordinary steel grades is prohibited (to improve the rolling efficiency of the unit). Simultaneously, the number of hot rolls before rolling non-oriented silicon steel is controlled to 10-15 pieces (or within 15km); the coiling time before and after finishing rolling of the four steel pieces before roll change is controlled to be above 30 seconds, which is beneficial for the formation of the oxide film on the rolls; within the rolling cycle, the work roll diameter of each finishing stand should decrease gradually from F1 to F7; the hardness of the hot roll material must be higher than the hardness of the rolled silicon steel, and the thickness must transition from 4.7mm to 2.7mm; the width of the hot roll material must be greater than the width of the non-oriented silicon steel, and reverse width rolling is not allowed.

[0039] S2. Adjustment of rolling process; The heating temperature of the steel must reach the standard temperature difference range. At the same time, for long-term planned shutdown of rolling, space should be reserved for the furnace head steel to prevent transverse temperature difference of slab caused by poor sealing of the heating furnace.

[0040] During the high-temperature heating process, the transverse temperature difference of the slab should be controlled within 30℃, the head and tail temperatures should be slightly higher than the body temperature by more than 20℃, the inter-furnace temperature difference should be controlled within 30℃, and the steel firing temperature must reach the standard temperature difference range. At the same time, for planned shutdowns of rolling for a long period of time (more than 10 minutes), a space should be reserved for the furnace head steel to prevent transverse temperature differences of the slab caused by poor sealing of the heating furnace.

[0041] During rough rolling, three passes of R1 rolling and three passes of R2 rolling are adopted. The thickness of the intermediate slab is controlled to be above 40 mm, the wedge shape is less than 0.2 mm, and the reduction in the width direction of the slab is less than 40 mm. At the same time, the overall sickle shape of the intermediate slab is controlled, and the offset between the rolling centerline and the centerline of the intermediate slab during rolling does not exceed 20 mm. During the transition material period before the production of non-oriented silicon steel, leveling control is performed to adjust the wedge shape of the strip within the standard range before it is coiled in a hot coil box.

[0042] During the seven-stand continuous rolling process, the reduction rate of F1 to F3 shall not be less than 42%, 25% ≤ F4 to F6 < 38%, and F7 < 20%.

[0043] Among them, F1 to F4 are CVC rollers, and F5 to F7 are special work roller types, namely edge-descending roller types (such as...). Figure 2 As shown), the crown value is controlled within -150μm; the seven-stand rolling mill is equipped with positive bending roll force adjustment function, with a setting range of 50 to 80T, and decreasing with each stand.

[0044] S3, the linkage and tension optimization of bending and shifting rolls; the downstream stand adopts a special work roll type, namely a work roll with slow edge descent, thereby realizing the edge descent control of strip steel, laying a good cross-sectional foundation for the same plate difference of cold rolled finished products;

[0045] Silicon steel has strict requirements for edge thinning. Therefore, special work roll shape technology (edge-descending work rolls) is used in the downstream stand of hot rolling to control the edge drop of the strip. The effect is even better when these work rolls are paired with a proprietary asynchronous sinusoidal roll shifting strategy (such as...). Figure 3 (As shown). Because the edge-descent work roll has strong edge-descent control capability in the edge area, it can achieve a very good crown control effect when the roll is undergoing maximum roll shifting.

[0046] The strength and plasticity of the steel plate affect the rolling reduction rate and roll profile settings, which in turn affect the rolling force. Given these parameters, the bending roll force of each stand is dynamically calculated through roll crown calculation to achieve good head and tail plate shape quality. The bending roll setting calculation model is shown in Table 1.

[0047] Table 1

[0048]

[0049]

[0050] The calculation formula is:

[0051]

[0052] S4. Strip crown control; the crown self-learning gain coefficient is crucial. During continuous rolling production, the self-optimization is automatically performed by increasing the number of crown self-learning cycles.

[0053] The crown of non-oriented silicon steel sheets is closely related to their inherent properties and rolling process. Since it affects surface quality and post-processing performance of the product, crown control has always been a key control point for hot rolling mills.

[0054] In the industrial setting, an online measurement feedback system is used to adjust the bending roll force of each stand on the rolling mill, achieving dynamic adjustment during production and eliminating deviations. In terms of process, optimizing process parameters and rolling strategies, such as cooled rolling and optimizing rolling reduction, improves plate crown. Furthermore, optimizing the roll profile can also adjust the plate crown closer to the edges of the steel plate, such as the crown at a distance of 25mm from the edge.

[0055] In this invention, the convexity self-learning algorithm is as follows:

[0056]

[0057] In the formula: ΔC c (i+1) is the self-learning value of the convexity of the (i+1)th strip; ΔC c (i) represents the self-learning value of the convexity of the i-th strip; k is the adjustment amount of the model coefficient calculated based on the measured value of the crown of the i-th strip;c This is the convexity self-learning gain coefficient.

[0058] The crown control system of the continuous rolling production line performs real-time self-learning calculations based on the steel plate rolling data during actual production, thereby updating the model itself. Errors may occur during the self-update process, mainly generated by the steel plate data during rolling. The input of these error messages will affect the accuracy and stability of the model. Excessive correction will affect its stability, while insufficient correction will not accurately and effectively approximate the current system.

[0059] Therefore, the self-learning gain coefficient of crown is crucial. During continuous rolling production, it automatically optimizes itself by increasing the number of self-learning cycles. The short-term self-learning of the crown control system is based on alloy element content, steel plate width, and thickness to ensure the effectiveness of the learning. Correspondingly, long-term self-learning corrects the overall error based on these parameters. For example, some steel coils may exhibit compositional differences during the data acquisition process, resulting in outliers in the dataset. After the model acquires these outliers, they are removed according to the Pauta criterion. Control parameters with actual crown values ​​below 0.75 times or above 1.3 times the target crown value are not included in the self-learning data; that is, after deducting outlier data, the system continuously learns and corrects itself based on the mean and standard deviation of the overall sample. Many factors affect the control of plate crown. Among them, the fluctuation range of the temperature at the entry and finishing mills significantly affects the stable control of silicon steel plate crown. Therefore, strictly controlling the entry and finishing mill temperatures to avoid sudden fluctuations above 20°C is highly beneficial for ensuring the accuracy of crown control.

[0060] S5. Control of the opening of the finishing mill vertical rolls and guide rollers: First, the opening of the vertical rolls before entering the finishing mill is oscillated according to the side pressure; In addition, the roughing mill control process needs to adjust the roll gap balance of each pass of the roughing mill stand according to the actual measurement feedback of the previous coil of steel.

[0061] A comparison of the hot-rolled wedge curve and the corresponding deviation value shows a very high degree of agreement between the deviation value and the corresponding wedge shape (e.g., Figure 4 (As shown). Therefore, in order to control strip deviation, the opening of the vertical rolls before entering the finishing mill is first oscillated according to the side pressure; the opening of the finishing mill guide is set to compensate by increasing the R2 exit width by 5mm; the wedge shape of the intermediate billet of the R2 incoming material in the roughing mill must be controlled within 0.05mm. The control process requires the operator to carefully adjust the roll gap balance of each pass of the roughing mill stand based on the actual measurement feedback of the previous coil.

[0062] The control of the wedge shape mainly depends on the leveling control of the roughing mill stand. Influencing factors include ensuring the accuracy of the stand gap, the gap between the work roll and the bearing housing, and the slab camber problem, which seriously affect the wedge shape control of the intermediate slab. At the same time, the wedge shape of hot-rolled products cannot rely entirely on roughing mill control; the wedge shape fluctuating within a certain range can also be finely improved by adjusting the finishing mill reduction.

[0063] S6, Loop unit tension control;

[0064] Loop tension setting range: 6–14 N / mm 2 The rate of change gradually increases with the number of stands. The looper raising and lowering process is divided into five stages: looper raising, looper tension stabilization, looper angle stabilization at the set angle, stable rolling stage, and looper lowering stage before lowering. During continuous rolling of steel plates, the roll gap and control system between stands will dynamically adjust at the tail end of the strip due to dynamic changes in specifications. At this time, the flow rate will fluctuate slightly. The adjustment range is narrow at small angles, which may lead to large angle fluctuations. When rolling non-oriented silicon steel, this may cause the strip to narrow or break and sag.

[0065] Plate convexity and wedge parameters are as follows Figure 5 and 6 As shown in the figure, the above measures ensure that the plate convexity and wedge shape meet the standard tolerance range, effectively guaranteeing the cross-sectional shape of the hot-rolled non-oriented silicon steel and providing good hot-rolled raw material for cold-rolled steel sheets. If advanced technologies for measuring and controlling the camber of roughing mill intermediate slabs and the deviation between mill stands are adopted, avoiding complete reliance on manual operation, and realizing automatic correction and control technology and systems for the asymmetric plate shape of wedges and cambers, the dimensional accuracy of the hot-rolled non-oriented silicon steel cross-section can be significantly improved.

[0066] All matters not covered in this invention are common knowledge.

[0067] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel, characterized in that, The method includes the following steps: S1. Rolling schedule arrangement; the hardness of the transition material during the silicon steel rolling cycle must be close to that of silicon steel, and the hot roll material stage must ensure the full formation of the oxide film on the rolls; at the same time, the rolling mileage of the work rolls within a rolling cycle should be controlled within a reasonable range to prevent local high points from appearing on the cross-section. S2. Adjustment of rolling process; The heating temperature of the steel must reach the standard temperature difference range. At the same time, for long-term planned shutdown of rolling, space should be reserved for the furnace head steel to prevent transverse temperature difference of slab caused by poor sealing of the heating furnace. In step S2, during the high-temperature heating process of the slab, the transverse temperature difference is controlled within 30°C, the head and tail temperatures are more than 20°C higher than the body temperature, and the inter-furnace temperature difference is controlled within 30°C. During the rough rolling process, three passes of R1 rolling and three passes of R2 rolling are adopted, the thickness of the intermediate slab is controlled to be more than 40mm, the wedge shape is less than 0.2mm, and the width reduction of the slab is less than 40mm. At the same time, the overall sickle shape of the intermediate slab is controlled, and during the rolling process, the offset between the rolling center line and the intermediate slab center line does not exceed 20mm. During the transition material period before the production of non-oriented silicon steel, leveling control is performed to adjust the strip wedge shape within the standard range before it is coiled in the hot coil box. S3, the linkage and tension optimization of bending and shifting rolls; the downstream stand adopts a special work roll type, namely a work roll with slow edge descent, thereby realizing the edge descent control of strip steel, laying a good cross-sectional foundation for the same plate difference of cold rolled finished products; S4. Strip crown control; automatically optimizes itself by increasing the number of self-learning crown counts. S5. Control of the opening of the vertical rolls and guides in the finishing mill: First, the opening of the vertical rolls before entering the finishing mill is oscillated according to the side pressure; In addition, the roughing mill control process requires adjusting the roll gap balance of each pass of the roughing mill stand based on the actual measurement feedback of the previous coil. S6, Loop unit tension control; In step S6, the unit tension setting range for the looper is 6–14 N / mm. 2 .

2. The method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel according to claim 1, characterized in that: In step S1, the number of hot-rolled rolls before rolling non-oriented silicon steel is controlled within 10-15 pieces or 15km; the time for the steel to bite before and after finishing rolling of the four steel pieces before changing rolls is controlled to be more than 30 seconds, which is conducive to the formation of oxide film on the rolls; during the rolling cycle, the diameter of the work rolls in each stand of finishing rolling decreases from F1 to F7 in each stand; the hardness of the hot-rolled roll material is higher than that of the silicon steel being rolled, and the thickness meets the requirement of transitioning from 4.7mm to 2.7mm; the width of the hot-rolled roll material is greater than the width of the non-oriented silicon steel, and reverse width rolling is not allowed.

3. The method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel according to claim 1, characterized in that: During the seven-stand continuous rolling process, the reduction rate of F1 to F3 is not less than 42%, 25% ≤ F4 to F6 < 38%, and F7 < 20%; F1 to F4 are CVC rolls, and F5 to F7 are special work rolls with crown values ​​controlled within -150μm; the seven-stand mill is equipped with a positive bending roll force adjustment function, with a setting range of 50 to 80T, and decreasing with each stand.

4. The method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel according to claim 1, characterized in that: In step S3, the bending roll force of each stand is dynamically calculated by learning the calculation of the roll crown, thereby obtaining good head and tail plate shape quality; the bending roll setting calculation formula is: (1) In the formula, B f Set the calculated value for the bending roller force; C m For the mechanical crown of the strip; R f Set the rolling force value; C WC The composite roll shape in the middle of the work roll body; C WE The overall roll shape of the working roll body; C BC To support the overall roll shape in the middle of the roll body; C BE To support the overall roll profile of the roll body; C WR The initial roll shape of the work roll; k BF k is the influence coefficient of the bending roller force. WC k is the influence coefficient of the roll shape in the middle of the work roll. WE k is the influence coefficient of the roll shape at the edge of the work roll. BC Support roller center roll shape influence coefficient; k BE To support the influence coefficient of roll edge shape; k CWR k is the influence coefficient of the initial roll shape of the work roll. CST k is a constant coefficient. RF This is the rolling force influence coefficient.

5. The method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel according to claim 1, characterized in that: In step S4, the convexity self-learning algorithm is as follows: (2) In the formula: The self-learning value for the convexity of the (i+1)th strip; Let be the self-learning value of the convexity of the i-th strip. This refers to the adjustment amount of the model coefficients calculated based on the measured value of the crown of the i-th strip. This is the convexity self-learning gain coefficient.

6. The method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel according to claim 1, characterized in that: Step S5 specifically includes: in order to control strip deviation, the opening of the vertical roll before entering the finishing mill is first oscillated according to the side pressure; the opening of the finishing mill guide is set to compensate by increasing the R2 exit width by 5mm; the wedge shape of the intermediate billet of the R2 incoming material in the roughing mill is controlled within 0.05mm, and the roll gap balance of each pass of the roughing mill stand is carefully adjusted according to the actual measurement feedback of the previous coil of steel.

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