Method for controlling section shape of hot-rolled non-oriented silicon steel

Abstract

The invention relates to a control method for the section shape of hot-rolled non-oriented silicon steel. The control method comprises the steps that S1, a rolling plan is arranged; s2, adjusting a rolling process; s3, roll bending and roll shifting linkage and tension optimization are carried out; s4, controlling the convexity of the strip steel; s5, controlling the opening degree of a finish rolling vertical roll and a guide ruler; according to the method, the size control precision of the hot-rolled non-oriented silicon steel product can be effectively improved, the raw material requirements of the downstream cold rolling process are met in the aspects of thickness, convexity, wedge shape and transverse thickness difference, and the best hot-rolled raw material section shape guarantee is provided for improving the same plate difference index of the cold-rolled silicon steel product. And therefore, certain economic benefits are generated in the aspects of reducing the edge cutting amount and improving the comprehensive yield. And the overall quality level of the product is improved, and the high-standard requirements of terminal users for tabletting processing are met.

Description

Technical Field

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

[0002] As an important metal material, cold-rolled non-oriented silicon steel is widely used in motor manufacturing, etc. Silicon steel is usually processed as a single piece in the motor manufacturing process, and finally processed into an iron core by stacking. The product accuracy of cold-rolled non-oriented silicon steel sheets requires hot rolling to provide excellent raw material guarantee, especially in terms of plate convexity, wedge shape and transverse thickness difference.

[0003] Hot rolling of non-oriented silicon steel mainly controls the plate convexity and wedge shape of the strip, that is, the deformation of the plate and strip during the rolling process is used to control the flow of metal, and the plate convexity and wedge shape indicators are fed back through the multifunctional instrument at the finishing exit. The stability of the plate convexity and wedge shape of the whole roll determines the production stability of the cold rolling process. The cross-sectional shape of the hot-rolled product is completely inherited to the cold rolling process. For products with poor cross-section of the cold-rolled base material, there is little improvement after rolling on the cold rolling mill, and even rolling or scrapping may occur. 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 rate. The amount of edge cutting loss of silicon steel sheets is positively correlated with the yield rate. The less the cutting loss, the higher the yield rate. For the steelmaking process, the cross-sectional shape of the steelmaking slab is strictly controlled, that is, the wedge shape, side bending, temperature difference between the two sides and the head and tail of the slab are strictly controlled, which has an important impact on the shape of the subsequent silicon steel sheet; for the hot rolling rough rolling stage, the plate shape control of the rough rolling is very important, which will affect the convexity and wedge shape indicators of the next process. It must be straight and without side bending, and the wedge shape of the intermediate slab must also meet the standards. Finishing rolling is the last process to control the cross-sectional shape of the product and is the core process to ensure quality indicators. It involves pressure reduction and leveling control, plate and strip centering rolling, work roll shape design, work roll shifting, looper tension setting, bending roll force control and convexity self-learning.

[0004] The cross-sectional shape of hot-rolled silicon steel products is completely inherited from the cold rolling process. At present, the hit rate of hot-rolled silicon steel products within the range of 20μ±10 convexity is less than 74%; the hit rate within the range of ±15μ wedge shape is less than 65%, and the qualified rate of silicon steel products with a thickness difference of less than 8um is less than 50%, which is much lower than the qualified rate of more than 85% of similar steel enterprises. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is 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 the downstream cold rolling process in terms of thickness, convexity, wedge shape and lateral thickness difference, and provide the best 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 by the present invention is as follows:

[0007] A method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel proposed in the present invention comprises the following steps:

[0008] S1. Rolling plan arrangement; the hardness of the transition material in the silicon steel rolling cycle must be close to that of silicon steel, and the roll oxide film must be fully formed during the hot roll material stage; at the same time, the rolling mileage of the working roll in a rolling cycle is controlled within a reasonable range to prevent local high points from appearing on the cross section;

[0009] S2. Adjustment of rolling process: The steel burning temperature must be within the standard temperature difference range. At the same time, when the rolling is stopped for a long time, a space should be reserved for the furnace head steel to prevent the lateral temperature difference of the slab caused by the poor sealing of the heating furnace.

[0010] S3, optimization of the linkage and tension of the bending and shifting rolls; the downstream stand adopts a special working roll profile, that is, a working roll with a slow edge drop, thereby realizing the edge drop control of the strip, laying a good foundation for the same plate difference of the cold-rolled finished product;

[0011] S4, strip crown control; automatic self-optimization through increasing the number of crown self-learning times;

[0012] S5, finishing roll and guide opening control; first, the roll opening before finishing rolling is swung according to the side pressure; in addition, the rough rolling control process needs to adjust the roll gap balance of each pass of the rough rolling stand according to the measured feedback of the previous coil;

[0013] S6, loop unit tension control.

[0014] Furthermore, in the step S1, the hot roll material before rolling the non-oriented silicon steel is controlled within 10 to 15 pieces or 15 km; the coiling and biting time of the four pieces of steel before and after the finish rolling is controlled to be more than 30 seconds, which is conducive to the formation of the roller oxide film; during the rolling cycle, the diameter of the working rolls of each finishing rolling is reduced from F1 to F7; the hardness of the hot roll material is higher than that of the rolled silicon steel, and the thickness meets the transition from 4.7 mm to 2.7 mm; 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 lateral temperature difference is controlled within 30°C, the head and tail temperatures are higher than the body temperature by more than 20°C, the temperature difference between furnaces is controlled within 30°C, and the steel burning temperature must reach the standard temperature difference range; during the rough rolling process, R1 rolling is performed for 3 times and R2 rolling is performed for 3 times, the thickness of the intermediate billet is controlled to be above 40mm, the wedge shape is less than 0.2mm, and the width direction reduction of the billet is less than 40mm; at the same time, the overall sickle bending state of the intermediate billet is controlled, and during the rolling process, the offset between the rolling center line and the center line of the intermediate billet does not exceed 20mm; leveling control is performed during the transition material before the production of non-oriented silicon steel, and the wedge shape of the strip is adjusted to be within the standard range, and then coiled by the hot coil box.

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

[0017] Furthermore, in step S3, the bending roll force of each stand is dynamically calculated by learning the calculation of the roll crown, thereby obtaining a 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 roll force; C m R is the mechanical crown of the strip; f is the rolling force setting value; C WC It is the comprehensive roll shape of the middle part of the working roll body; C WE C is the comprehensive roll shape of the working roll side; BC It is the comprehensive roll shape of the middle part of the support roll body; C BE The comprehensive roll shape of the support roll side; C WR is the initial roll shape of the working roll; k BF k is the bending roll force influence coefficient; WC k is the roll shape influence coefficient of the middle part of the working roll; WE k is the roll shape influence coefficient of the working roll edge; BC Roller shape influence coefficient of the middle part of the support roll; k BE k is the roller shape influence coefficient of the support roller edge; CWR k is the initial roll shape influence coefficient of the working roll; CST is a constant coefficient; k RF is the rolling force influence coefficient.

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

[0021]

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

[0023] Furthermore, the step S5 specifically includes: in order to control the deviation of the strip, firstly, the opening degree of the vertical roll before finishing rolling is swung according to the side pressure; the opening degree of the finishing rolling guide is set by increasing the R2 outlet width by 5mm for compensation; the wedge degree of the intermediate billet of the rough rolling R2 incoming material is controlled within 0.05mm, and the control process carefully adjusts the roll gap balance of each pass of the rough rolling stand according to the actual measured feedback of the previous coil of steel.

[0024] Furthermore, in step S6, the looper unit tension setting range is 6 to 14 N / mm. 2 .

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

[0026] The present invention standardizes the planning arrangement within a rolling cycle, the steel burning quality of the slab in the heating furnace, the plate shape control in the rough rolling area, and the optimization and regulation of the equipment such as the rollers and guide gauges in the finishing rolling area. The finishing rolling utilizes control means such as leveling control, AGC adjustment and tension optimization to achieve good cross-sectional dimensional accuracy of convexity and wedge shape less than 25μm, avoids the phenomenon that the convexity of the plate fluctuates greatly throughout the roll and the wedge shape index exceeds the convexity value of the plate, solves the problem of inconsistent cross-section of the cold-rolled base material of non-oriented silicon steel, and the rolling rate of the non-oriented silicon steel rolled by the cold rolling mill in the downstream process is increased to more than 95%, which is better than the existing level. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the existing hot rolling production process flow chart;

[0028] Figure 2 It is a schematic diagram comparing the F5-F7 roller type with the conventional roller type;

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

[0030] Figure 4 It is a comparison diagram of hot rolling wedge curve and corresponding deviation value;

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

[0032] Figure 6 Schematic diagram of wedge control curve. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] The production process of non-oriented silicon steel is mainly smelting → continuous casting → hot rolling → pickling → cold rolling → continuous annealing → coating → rewinding. Among them, the equipment for hot rolling production of non-oriented silicon steel is as follows: Figure 1 As shown, it consists of three walking-beam heating furnaces, descaling before rolling, R1 two-roll rough rolling, R2 four-roll rough rolling, hot coil box, flying shear, fine descaling, F1~F7 finishing rolling, laminar cooling and coiling machine; among them, HF1-HF3: three heating furnaces; HSB: dephosphorization for rough rolling; R1D: dephosphorization before R1; R2D: dephosphorization before R2; E1, E2: vertical rollers before rough rolling; RT: pyrometer before rough rolling; R1, R2: two rolling mills for rough rolling; CB: hot coil box; CS: flying shear; FET: pyrometer at the entrance of finishing rolling; FSB: dephosphorization for finishing rolling; F1E: vertical rollers before finishing rolling; F1-F7: 7 rolling mills for finishing rolling; FDT: pyrometer at the exit of finishing rolling; LCS: laminar cooling mechanism; CT: pyrometer before coiling; DC1-DC3: three down-coilers for taking up.

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

[0036] See attached Figure 2-6 The present invention proposes a method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel, and the specific implementation steps are as follows:

[0037] S1. Rolling plan arrangement; the hardness of the transition material in the silicon steel rolling cycle must be close to that of silicon steel, and the roll oxide film must be fully formed during the hot roll material stage; at the same time, the rolling mileage of the working roll in a rolling cycle is controlled within a reasonable range to prevent local high points from appearing on the cross section;

[0038] In the hot rolling production process, in order to ensure the surface quality of the plate and strip and the dimensional accuracy of the product during the rolling process, through multiple tests, adjustments and analyses, it is concluded that in each working roll cycle, after the transition from ordinary steel hot roll material to non-oriented silicon steel, silicon steel needs to be continuously rolled, and cross-rolling with ordinary steel grades is not allowed (in order to improve the rolling efficiency of the unit). At the same time, the number of hot roll materials before rolling non-oriented silicon steel is controlled at 10 to 15 pieces (or within 15km); the coiling and biting time of the four pieces of steel before and after the finishing rolling is controlled at more than 30S before the roll change and rolling, which is conducive to the formation of the roll oxide film; the roll diameter of each work roll of the finishing rolling in the rolling cycle should be reduced from F1 to F7 one by one; the hardness of the hot roll material should be higher than the hardness of the rolled silicon steel, and the thickness should meet the transition from 4.7mm to 2.7mm; the width of the hot roll material should 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 steel burning temperature must be within the standard temperature difference range. At the same time, when the rolling is stopped for a long time, a space should be reserved for the furnace head steel to prevent the lateral temperature difference of the slab caused by the poor sealing of the heating furnace.

[0040] During the high-temperature heating process of the slab, its transverse temperature difference is controlled within 30°C, the head and tail temperatures are slightly higher than the main body temperature by more than 20°C, the temperature difference between furnaces is controlled within 30°C, and the steel burning temperature must reach the standard temperature difference range. At the same time, when the rolling is planned to be stopped for a long time (more than 10 minutes), space must be reserved for the furnace head steel to prevent the transverse temperature difference of the slab caused by poor sealing of the heating furnace.

[0041] During the rough rolling process, R1 rolling is performed for 3 times and R2 rolling is performed for 3 times. The thickness of the intermediate billet is controlled to be above 40mm, the wedge shape is less than 0.2mm, and the width direction reduction of the billet is less than 40mm. At the same time, the overall sickle bending state of the intermediate billet is controlled. During the rolling process, the offset between the rolling center line and the center line of the intermediate billet does not exceed 20mm. During the transition period before the production of non-oriented silicon steel, leveling control is performed to adjust the strip wedge shape within the standard range, and then coiled by the hot coil box.

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

[0043] Among them, F1~F4 are CVC rolls, and F5~F7 are special working rolls, that is, edge slow-down rolls (such as Figure 2 As shown), the convexity value is controlled within -150μm; the seven rolling mills are equipped with positive bending roll force adjustment function, the setting range is 50~80T, and it decreases with each mill.

[0044] S3, optimization of the linkage and tension of the bending and shifting rolls; the downstream stand adopts a special working roll profile, that is, a working roll with a slow edge drop, thereby realizing the edge drop control of the strip, laying a good foundation for the same plate difference of the cold-rolled finished product;

[0045] Silicon steel has strict requirements for edge thinning, so special work roll profile technology (edge ​​slow-drop work roll) is used in the downstream stand of hot rolling to control the edge drop of strip steel. The effect is better when such work rolls are equipped with a proprietary asynchronous sinusoidal roll shifting strategy (such as Figure 3 As shown in the figure). Since the edge area of ​​the edge slow-drop work roll has a strong edge drop control capability, a good crown control effect can be achieved when the roll is at its maximum roll shifting.

[0046] The strength and plasticity of the steel plate affect the setting of the rolling reduction rate and the roll shape, that is, the size of the rolling force. When the two are determined, the dynamic change calculation of the bending roll force of each stand is carried out through the calculation and learning of the roll crown, so as to obtain a 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 very important. In the continuous rolling production process, the crown self-learning times are increased to automatically optimize the steel strip.

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

[0054] The industrial site uses an online measurement feedback system to adjust the bending roll force of each stand of the rolling mill, realize dynamic adjustment during the production process, and eliminate deviations. In terms of technology, the plate crown is improved by optimizing process parameters and rolling strategies, such as cooling rolling and optimizing rolling reduction rate. In addition, the plate crown closer to the edges of the steel plate can also be adjusted by optimizing the roll shape, such as the plate crown 25mm away from the edge.

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

[0056]

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

[0058] The convexity control system of the continuous rolling production line performs self-learning calculations based on the steel plate rolling data during the actual production process, and then the model is self-updated. Errors may occur in the data during self-updating, mainly caused by the data of the steel plate during the rolling process. The input of these error information will affect the correctness and stability of the model. Too large a correction will affect its stability, and too small a correction will not be able to truly and effectively approach the current system.

[0059] Therefore, the convexity self-learning gain coefficient is crucial. In the continuous rolling production process, self-optimization is automatically performed by increasing the number of self-learning times. The short-term self-learning of the convexity control system is established based on the alloy element content, steel plate width and thickness, etc., to ensure the effectiveness of learning; correspondingly, the long-term self-learning is to correct the overall error based on these parameters. For example, some steel coils in production have composition differences during the collection process, and outliers appear in the data set. After the model collects the outliers, it is removed according to the Pauta criterion; the control parameters whose actual convexity is less than 0.75 times the target convexity or exceeds 1.3 times the target convexity are not included in the self-learning collection, that is, after deducting the abnormal data, the self-learning correction is continuously made according to the mean and standard deviation of the overall sample. There are many factors that affect the regulation of plate convexity. Among them, the rise and fall of the finishing rolling temperature and the final rolling temperature seriously affect the stable control of the convexity of silicon steel plates. Therefore, strictly implementing the finishing rolling steel feeding temperature and the final rolling temperature to avoid sudden fluctuations above 20°C is very beneficial to ensure the accuracy of convexity control.

[0060] S5. Control of the opening of the finishing rolls and guide bars. First, the opening of the vertical rolls before finishing is swung according to the side pressure. In addition, the rough rolling control process needs to adjust the roll gap balance of each pass of the rough rolling stand according to the measured feedback of the previous coil.

[0061] From the comparison between the hot rolling wedge curve and the corresponding deviation value, the deviation value is very consistent with the corresponding wedge degree (such as Figure 4 Therefore, in order to control the deviation of the strip, the opening of the vertical roll before finishing rolling is first swung according to the side pressure; the opening of the finishing guide gauge is set according to the R2 outlet width plus 5mm compensation; the wedge degree of the R2 incoming intermediate billet in rough rolling must be controlled within 0.05mm. The control process requires the operator to carefully adjust the roll gap balance of each pass of the rough rolling stand according to the actual measurement feedback of the previous coil of steel.

[0062] The wedge shape control mainly depends on the leveling control of the rough rolling stand. The influencing factors include the accuracy of the stand gap, the gap between the working roll and the bearing box, and the slab sickle problem, which seriously affect the wedge shape control of the intermediate billet. At the same time, the wedge shape of hot-rolled products cannot be completely dependent on the rough rolling control. The wedge shape that fluctuates within a certain range can also be finely improved by adjusting the finishing rolling pressure.

[0063] S6, looper unit tension control;

[0064] Loop unit tension setting range 6~14N / mm 2 , and gradually increases with the increase of the number of lifts. The process of the looper is divided into five stages, which are the looper starting, the stable establishment of the looper tension, the stable looper angle at the set angle, the stable rolling stage, and the small looper drop stage before the looper drops. During the continuous rolling process of the steel plate, due to the dynamic change of specifications at the tail of the strip, the roll gap between the stands and the control system will be dynamically adjusted. At this time, the flow rate per second fluctuates slightly. The adjustment range is narrow at a small angle, which is likely to cause a large angle fluctuation. When rolling non-oriented silicon steel, it may cause the strip to narrow or break and swing out of the tail.

[0065] Plate convexity and wedge parameters such as Figure 5 and 6 As shown in the figure. It can be seen from the figure that, through the favorable guarantee of the above measures, the plate convexity and wedge shape meet the standard tolerance range, effectively ensuring the cross-sectional shape of hot-rolled non-oriented silicon steel, and providing good hot-rolled raw materials for cold-rolled steel plates. If the currently advanced rough rolling intermediate billet sickle bending and finishing mill inter-stand deviation measurement and control technology are adopted to avoid relying entirely on manual control, and to realize the asymmetric plate shape automatic correction control technology and control system of wedge and sickle bending, the dimensional accuracy of the hot-rolled non-oriented silicon steel section can be greatly improved.

[0066] Matters not described in detail in the present invention are all known technologies.

[0067] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined 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 comprises the following steps: S1. Rolling plan arrangement; the hardness of the transition material in the silicon steel rolling cycle must be close to that of silicon steel, and the roll oxide film must be fully formed during the hot roll material stage; at the same time, the rolling mileage of the working roll in a rolling cycle is controlled within a reasonable range to prevent local high points from appearing on the cross section; S2. Adjustment of rolling process: The steel burning temperature must be within the standard temperature difference range. At the same time, when the rolling is stopped for a long time, a space should be reserved for the furnace head steel to prevent the lateral temperature difference of the slab caused by the poor sealing of the heating furnace. S3, optimization of the linkage and tension of the bending and shifting rolls; the downstream stand adopts a special working roll profile, that is, a working roll with a slow edge drop, thereby realizing the edge drop control of the strip, laying a good foundation for the same plate difference of the cold-rolled finished product; S4, strip crown control; automatic self-optimization through increasing the number of crown self-learning times; S5, finishing roll and guide opening control; first, the roll opening before finishing rolling is swung according to the side pressure; in addition, the rough rolling control process needs to adjust the roll gap balance of each pass of the rough rolling stand according to the measured feedback of the previous coil; S6, loop unit tension control.

2. The method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel according to claim 1, characterized in that: In the step S1, the hot roll material before rolling the non-oriented silicon steel is controlled within 10 to 15 pieces or 15 km; the coiling and biting time of the four pieces of steel before and after the finish rolling is controlled to be more than 30 seconds, which is conducive to the formation of the roller oxide film; during the rolling cycle, the diameter of the working rolls of each finishing rolling is reduced from F1 to F7; the hardness of the hot roll material is higher than that of the rolled silicon steel, and the thickness meets the transition from 4.7 mm to 2.7 mm; the width of the hot roll material is greater than that 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: In the step S2, during the high-temperature heating process of the slab, the lateral temperature difference is controlled within 30°C, the head and tail temperatures are higher than the body temperature by more than 20°C, the temperature difference between furnaces is controlled within 30°C, and the steel burning temperature must reach the standard temperature difference range; during the rough rolling process, R1 rolling is performed for 3 times and R2 rolling is performed for 3 times, the thickness of the intermediate billet is controlled to be above 40mm, the wedge shape is less than 0.2mm, and the width direction reduction of the billet is less than 40mm; at the same time, the overall sickle bending state of the intermediate billet is controlled, and during the rolling process, the offset between the rolling center line and the center line of the intermediate billet does not exceed 20mm; leveling control is performed during the transition material before the production of non-oriented silicon steel, and the wedge shape of the strip is adjusted to be within the standard range, and then it is coiled by the hot coil box.

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

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 S3, the bending roll force of each stand is dynamically calculated by learning the calculation of the roll crown, thereby obtaining a good head and tail plate shape quality; the bending roll setting calculation formula is: In the formula, B f Set the calculated value for the bending roll force; C m R is the mechanical crown of the strip; f is the rolling force setting value; C WC It is the comprehensive roll shape of the middle part of the working roll body; C WE C is the comprehensive roll shape of the working roll side; BC It is the comprehensive roll shape of the middle part of the support roll body; C BE The comprehensive roll shape of the support roll side; C WR is the initial roll shape of the working roll; k BF k is the bending roll force influence coefficient; WC k is the roll shape influence coefficient of the middle part of the working roll; WE k is the roll shape influence coefficient of the working roll edge; BC Roller shape influence coefficient of the middle part of the support roll; k BE k is the roller shape influence coefficient of the support roller edge; CWR k is the initial roll shape influence coefficient of the working roll; CST is a constant coefficient; k RF is the rolling force influence coefficient.

6. 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 algorithm of convexity self-learning is as follows: Where: ΔC c (i+1) is the self-learning value of the convexity of the i+1th strip; ΔC c (i) is the self-learning value of the crown of the i-th strip; is the model coefficient adjustment amount calculated based on the measured convexity value of the i-th strip steel; k c is the convexity self-learning gain coefficient.

7. The method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel according to claim 1, characterized in that: The step S5 specifically includes: in order to control the deviation of the strip steel, firstly, the opening degree of the vertical roll before finishing rolling is swung according to the side pressure; the opening degree of the finishing rolling guide gauge is set to compensate by adding 5mm according to the R2 outlet width; the wedge degree of the R2 incoming intermediate billet of the rough rolling is controlled within 0.05mm, and the control process carefully adjusts the roll gap balance of each pass of the rough rolling stand according to the actual measured feedback of the previous coil of steel.

8. The method for controlling the cross-sectional shape of hot-rolled non-oriented silicon steel according to claim 1, characterized in that: In step S6, the setting range of the loop unit tension is 6 to 14 N / mm 2 .

Images