Method of reducing transverse strip variation in silicon steel products

Abstract

The application provides a method for reducing the transverse strip difference of silicon steel products, comprising the following steps: S1, increasing the original roll crown of a cold rolling silicon steel rolling mill; S2, moving the upper and lower intermediate rolls of the cold rolling silicon steel rolling mill, and determining the position of the axial movement of the upper and lower intermediate rolls according to the width of the strip steel; S3, adjusting the bending roll of the cold rolling silicon steel rolling mill according to the rolling reduction rate, increasing the positive bending extension of the bending roll of the cold rolling silicon steel rolling mill; S4, increasing the total reduction rate of the cold rolling silicon steel rolling mill; S5, increasing the strip tension of the cold rolling silicon steel rolling mill; S6, reducing the strip difference of the cold rolling strip steel and improving the strip shape at the same time. The transverse strip difference of the silicon steel cold rolling strip steel can be reduced to 0.0048-0.0051, which meets the requirements of the manufacturers of motors, transformers and the like on the transverse strip difference of the silicon steel products.

Description

Technical Field

[0001] This invention relates to the field of cold rolling technology, and more particularly to a method for reducing transverse plate differences in silicon steel products. Background Technology

[0002] Transverse thickness deviation is the maximum thickness difference between any two points on the same strip, and it can be used to represent the surface flatness and processing accuracy of the strip. The smaller the transverse thickness deviation, the higher the flatness and processing accuracy of the strip. Domestically and internationally, transverse thickness deviation of electrical steel is generally reduced during hot or cold rolling by adjusting and controlling strip crown, edge drop, and straightness; however, the adjustment capability is relatively limited. Currently, the transverse thickness deviation of cold-rolled strip in China is between 0.008 and 0.01 mm, while silicon steel products require a transverse thickness deviation of less than 0.007 mm. Due to numerous complex factors during rolling, such as roll bounce, elastic deformation, uneven roll wear, thermal crown, roll bending, roll shifting, uneven temperature along the width of the strip surface, and uneven local deformation resistance caused by uneven strip material properties, it is extremely difficult to stably reduce the transverse thickness deviation to a lower level. Therefore, how to reduce / lower the transverse thickness deviation has become a very important issue in the field of production research. Summary of the Invention

[0003] In response to the aforementioned technical problems, a method for reducing transverse plate differences in silicon steel products is provided.

[0004] The technical means employed in this invention are as follows:

[0005] A method for reducing transverse thickness variation in silicon steel products includes the following steps:

[0006] S1. Increase the original roll crown of the cold-rolled silicon steel mill;

[0007] S2. Move the upper and lower intermediate rolls of the cold-rolled silicon steel mill, and determine the axial position of the upper and lower intermediate rolls according to the width of the strip.

[0008] S3. Adjust the bending rolls of the cold-rolled silicon steel mill according to the rolling reduction rate: increase the positive bending extension of the bending rolls of the cold-rolled silicon steel mill.

[0009] S4. Increase the total reduction rate of cold-rolled silicon steel mills;

[0010] S5. Increase the strip tension of the cold-rolled silicon steel mill;

[0011] S6. Reduce the difference between cold-rolled strip steel and the sheet, and improve the sheet shape.

[0012] Furthermore, in step S1, the initial roll crown of the cold-rolled silicon steel mill is 50-60 micrometers.

[0013] Furthermore, in step S2, the smaller the strip width, the greater the distance that the position of point A on the left side of the upper intermediate roll moves to the right of point L on the left side of the strip, and the greater the distance that the position of point B on the right side of the lower intermediate roll moves to the left of point R on the right side of the strip; the greater the strip width, the smaller the distance that the position of point A on the left side of the upper intermediate roll moves to the right of point L on the left side of the strip, and the smaller the distance that the position of point B on the right side of the lower intermediate roll moves to the left of point R on the right side of the strip.

[0014] Furthermore, when the strip width is greater than 1200mm and less than 1500mm, the upper intermediate roll point A is located 10mm to the left of the corresponding strip point L; the lower intermediate roll point B is located 10mm to the right of the corresponding strip point R.

[0015] When the strip width is greater than 1100mm and less than 1200mm, point A of the upper intermediate roll is aligned with point L of the strip; point B of the lower intermediate roll is aligned with point R of the strip.

[0016] When the strip width is greater than 1000mm and less than 1100mm, the upper intermediate roll point A is located 2mm to the right of the corresponding strip point L; the lower intermediate roll point B is located 2mm to the left of the corresponding strip point R.

[0017] When the strip width is greater than 800mm and less than 1000mm, the upper intermediate roll point A is located 10mm to the right of the corresponding strip point L; the lower intermediate roll point B is located 10mm to the left of the corresponding strip point R.

[0018] Furthermore, in step S3, when the total reduction rate of the cold-rolled silicon steel mill is greater than 70% and less than 75%, the positive bending extension length is 18mm.

[0019] When the total reduction rate of the cold-rolled silicon steel mill is greater than 75% and less than 80%, the positive bending extension length is 26mm.

[0020] When the total reduction rate of the cold-rolled silicon steel mill is greater than 80% and less than 85%, the positive bending extension length is 34mm.

[0021] When the total reduction rate of the cold-rolled silicon steel mill is greater than 85% and less than 89%, the positive bending extension length is 45mm.

[0022] Further, in step S4, the total reduction rate is the percentage of the ratio of the thickness of the incoming material before rolling minus the thickness after rolling to the thickness of the incoming material before rolling. The total reduction rate satisfies the following formula: ε=(T1-T2)÷T1×100%, where ε is the total reduction rate, T1 is the thickness of the incoming material before rolling, and T2 is the thickness after rolling.

[0023] The difference between the thickness of the raw material and the thickness of the strip before and after rolling is equal to the elongation coefficient of the strip. The elongation coefficient is the ratio of the thickness of the raw material before rolling to the thickness after rolling. The elongation coefficient satisfies the following formula: λ=T1 / T2=Δ / δ, which gives δ=Δ / λ=1 / (1-ε), where Δ is the difference between the raw material and the thickness of the strip after rolling.

[0024] It is found that the larger the total reduction rate ε, the larger the elongation coefficient λ, and the smaller the difference in the same plate after rolling δ. By increasing the total reduction rate of cold rolling, the transverse difference in the same plate in the strip width direction can be reduced, and the transverse difference in the same plate in the strip width direction that is high in the middle and low on both sides can also be reduced.

[0025] Furthermore, in step S4, the methods for increasing the total reduction rate of the cold-rolled silicon steel mill include:

[0026] S41. Increase the total reduction ratio by increasing the thickness of the incoming material while keeping the rolling thickness constant.

[0027] S42. Reduce transmission load and rolling pressure by increasing the number of rolling passes;

[0028] S43. Determine the incoming material thickness according to different steel grades and rolling thicknesses.

[0029] Furthermore, in step S5, the back tension and front tension of the strip are increased in each rolling pass, and the back tension and front tension are set for the increased rolling passes.

[0030] Furthermore, in step S6, based on the difference in sheet size between the cold-rolled strip and the sheet, correction is performed in each of the first to Nth passes of rolling; from the N+1th pass to the last pass, the reduction rate of a single pass is reduced to adjust the sheet shape; wherein, the value of N is determined according to different incoming materials.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. By implementing the method of the present invention, the transverse same-plate difference of silicon steel cold-rolled strip is reduced to 0.0048 to 0.0051, which meets the requirements of motor, transformer and other manufacturers for the transverse same-plate difference of silicon steel products.

[0033] 2. This invention increases the original roll crown of the cold-rolled silicon steel mill, which helps to reduce the harmful effects of the elastic bending deformation of the rolls on both sides of the strip during the rolling process, and reduces the transverse difference in width between the strip, which is higher in the middle and lower at both ends.

[0034] 3. The axial movement of the intermediate roll of the cold-rolled silicon steel mill of the present invention can reduce the elastic bending deformation of the work roll. Adjusting the moving position of the intermediate roll can reduce the transverse difference of the strip width direction, which is high in the middle and low on both sides.

[0035] 4. The present invention increases the positive bending extension of the bending cylinder of the cold-rolled silicon steel mill, which can offset the bending deflection of the roll caused by the rolling pressure, reduce the effect of the roll on the edge of the strip, and thus reduce the transverse difference of the strip width direction, which is higher in the middle and lower on both sides.

[0036] 5. The present invention increases the cold rolling reduction rate, which can reduce the transverse same-plate difference in the strip width direction where one side is larger than the other, and can also reduce the transverse same-plate difference in the strip width direction where the middle is higher than the two sides.

[0037] 6. This invention increases the strip tension in cold-rolled silicon steel mills, maintaining strip alignment and reducing the likelihood of lateral thickness discrepancies (higher thickness on one side and lower thickness on the other) in the strip width direction. Increasing strip tension also reduces rolling pressure and the elastic bending deformation of the rolls, thereby minimizing the lateral thickness discrepancy (higher in the middle and lower on both sides) in the strip width direction. Furthermore, the increased strip tension reduces the resistance to longitudinal extension while increasing the resistance to width extension, further contributing to reducing the lateral thickness discrepancy (higher in the middle and lower on both sides) in the strip width direction.

[0038] 7. This invention reduces the difference in sheet shape between cold-rolled strips and the sheet itself.

[0039] Based on the above reasons, this invention can be widely applied in fields such as cold rolling processes. Attached Figure Description

[0040] 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.

[0041] Figure 1 This is a flowchart of the method of the present invention.

[0042] Figure 2 This is a schematic diagram of adjusting the position of the intermediate roll of a cold-rolled silicon steel mill according to the present invention, wherein (a) is a schematic diagram of the intermediate roll in its initial position and (b) is a schematic diagram of the position of the intermediate roll after it has been moved.

[0043] Figure 3 The diagram shows a large wedge-shaped incoming material and the upper roll being tilted at a 3° angle to the upper surface of the strip. (a) is a diagram of the large wedge-shaped incoming material, and (b) is a diagram of the upper roll being tilted at a 3° angle to the upper surface of the strip. Detailed Implementation

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0047] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0048] Example 1

[0049] This invention provides a method for reducing the transverse same-plate difference of silicon steel products, which can reduce the transverse same-plate difference of silicon steel products to below 0.006, including the following steps:

[0050] 1. Increase the original roll crown of the cold-rolled silicon steel mill;

[0051] The roll surface is curved, and the roll crown is the difference between the diameter at the middle of the roll body and the diameter at both ends of the roll body. The original roll crown is the crown of the roll before it is heated before it is put on the mill. Increasing the original roll crown of the cold-rolled silicon steel mill helps to reduce the harmful effects of the elastic bending deformation of the roll on both sides of the strip during the rolling process, and reduces the transverse difference in width between the strip and the end, which is higher in the middle and lower at both ends.

[0052] 2. Adjust the position of the intermediate roll of the cold-rolled silicon steel mill;

[0053] The axial movement of the intermediate roll in a cold-rolled silicon steel mill can reduce the elastic bending deformation of the work roll. Adjusting the position of the intermediate roll can reduce the transverse difference in strip width, where the middle is higher than the sides.

[0054] 3. Increase the positive bending extension of the bending rolls in cold-rolled silicon steel mills;

[0055] Increasing the positive bending extension of the bending cylinder of the cold-rolled silicon steel mill can counteract the bending deflection of the roll caused by the rolling pressure, reduce the effect of the roll on the edge of the strip, and thus reduce the transverse difference of the strip width direction, which is higher in the middle and lower on both sides.

[0056] IV. Increase the total reduction rate of cold-rolled silicon steel mills;

[0057] The total reduction rate is the percentage of the ratio of the pre-roll thickness minus the post-roll thickness to the pre-roll thickness. The total reduction rate satisfies the following formula: ε = (T1 - T2) ÷ T1 × 100%, where ε is the total reduction rate, T1 is the pre-roll thickness, and T2 is the post-roll thickness. The elongation coefficient is the ratio of the pre-roll thickness to the post-roll thickness. According to the formula: the difference between the pre-roll thickness and the post-roll thickness equals the elongation coefficient of the strip, i.e., λ = Δ / δ. Rearranging, we get δ = Δ / λ = 1 / (1-ε), where λ is the elongation coefficient; Δ is the difference between the pre-roll thickness and the post-roll thickness; and δ is the difference between the pre-roll thickness and the post-roll thickness. The larger the total reduction rate ε of cold rolling, the larger the elongation coefficient λ, and the smaller the post-roll thickness difference δ. Therefore, increasing the cold rolling reduction rate can reduce both the transverse difference between the strip width (larger on one side and smaller on the other) and the transverse difference between the strip width (higher in the middle and lower on both sides).

[0058] 5. Increase the strip tension in cold-rolled silicon steel mills;

[0059] Increasing the strip tension in cold-rolled silicon steel mills can maintain the strip's alignment, making it less likely to produce a transverse thickness difference where one side of the strip is thicker than the other in the width direction. Increasing the strip tension can also reduce rolling pressure and decrease the elastic bending deformation of the rolls, thereby reducing the transverse thickness difference where the strip is higher in the middle and lower on both sides in the width direction. Due to the increased strip tension, the resistance to longitudinal extension of the strip decreases while the resistance to extension in the width direction increases, which also helps to reduce the transverse thickness difference where the strip is higher in the middle and lower on both sides in the width direction.

[0060] VI. To reduce the difference in quality between cold-rolled strips and improve the strip shape.

[0061] If the production method is incorrect, a significant reduction in the strip thickness variation in a single pass of hot rolling will lead to a deterioration in strip shape. Therefore, while reducing the strip thickness variation in the cold rolling process, it is also necessary to improve the strip shape.

[0062] Example 2

[0063] This invention discloses a method for reducing transverse thickness variation in silicon steel products, comprising the following steps:

[0064] 1. Increase the original roll crown of the cold-rolled silicon steel mill

[0065] The original roll crown of existing cold-rolled silicon steel mills is 26–38 micrometers. This invention increases the original roll crown of the cold-rolled silicon steel mill to 50–60 micrometers.

[0066] II. Adjusting the position of the intermediate roll of the cold-rolled silicon steel mill ( Figure 2 )

[0067] The position of the intermediate rolls is adjusted according to the strip width. The smaller the strip width, the greater the elastic bending deformation of the rolls, and the greater the transverse difference in strip width, with the middle being higher and the sides lower. In existing technology, regardless of the strip width, point A of the upper intermediate roll is aligned with point L of the strip; point B of the lower intermediate roll is aligned with point R of the strip. This invention determines the movement position of the intermediate rolls based on the strip width. The smaller the strip width, the greater the distance point A of the upper intermediate roll moves to the right of point L, and the greater the distance point B of the lower intermediate roll moves to the left of point R. The larger the strip width, the smaller the distance point A of the upper intermediate roll moves to the right of point L, and the smaller the distance point B of the lower intermediate roll moves to the left of point R.

[0068] 1. For strip widths greater than 1200mm and less than 1500mm: the upper intermediate roll point A is located 10mm to the left of the corresponding strip point L; the lower intermediate roll point B is located 10mm to the right of the corresponding strip point R.

[0069] 2. For strip widths greater than 1100mm and less than 1200mm: Point A of the upper intermediate roll is aligned with point L of the strip; Point B of the lower intermediate roll is aligned with point R of the strip.

[0070] 3. For strip widths greater than 1000mm and less than 1100mm: the upper intermediate roll point A is located 2mm to the right of the corresponding strip point L; the lower intermediate roll point B is located 2mm to the left of the corresponding strip point R.

[0071] 4. For strip widths greater than 800mm and less than 1000mm: the upper intermediate roll point A is located 10mm to the right of the corresponding strip point L; the lower intermediate roll point B is located 10mm to the left of the corresponding strip point R.

[0072] 3. Increase the positive bending extension of the bending rolls in cold-rolled silicon steel mills.

[0073] The adjustment of cold rolling rolls is based on the rolling reduction rate. The reduction rate is the percentage of the ratio of the thickness before rolling minus the thickness after rolling to the thickness before rolling (the percentage of the ratio of the thickness before rolling minus the thickness after rolling to the thickness before rolling).

[0074] 1. When the total reduction rate of a cold-rolled silicon steel mill is greater than 70% and less than 75%, the existing bending cylinder has a positive bending extension length of 12mm. The present invention has a positive bending extension length of 18mm.

[0075] 2. When the total reduction rate of the cold-rolled silicon steel mill is greater than 75% and less than 80%, the positive bending extension length of the existing bending roll cylinder is 18mm; the positive bending extension length of the present invention is 26mm.

[0076] 3. When the total reduction rate of the cold-rolled silicon steel mill is greater than 80% and less than 85%, the positive bending extension length of the existing bending roller cylinder is 26mm; the positive bending extension length of the present invention is 34mm.

[0077] 4. When the total reduction rate of the cold-rolled silicon steel mill is greater than 85% and less than 89%, the positive bending extension length of the existing bending roll cylinder is 36mm; the positive bending extension length of the present invention is 45mm.

[0078] IV. Increase the total reduction rate of cold-rolled silicon steel mills

[0079] The first step to increasing the total reduction rate of a cold-rolled silicon steel mill is to increase the incoming material thickness while keeping the rolling thickness constant. The second step is to reduce the transmission load and rolling pressure by increasing the number of rolling passes. The third step is to determine the incoming material thickness according to different steel grades and rolling thicknesses.

[0080] 1. 50W470, 50W600, and 50W800 grade steel.

[0081] Existing technology: incoming material thickness 2.55mm; rolling thickness 0.495mm; total reduction rate 80.58%. Single-stand reversible rolling mill with 5 rolling passes.

[0082] This invention features: incoming material thickness 2.72 mm; rolling thickness 0.495 mm; total reduction rate 82%. It utilizes a single-stand reversible rolling mill with 6 rolling passes.

[0083] 2. 50W1000 and 50W1300 grade steel.

[0084] Existing technology: incoming material thickness 2.55mm; rolling thickness 0.495mm; total reduction rate 80.58%. Single-stand reversible rolling mill with 5 rolling passes.

[0085] This invention features: incoming material thickness 2.72 mm; rolling thickness 0.495 mm; total reduction rate 82%. It utilizes a single-stand reversible rolling mill with 6 rolling passes.

[0086] 3. 50W800 grade steel.

[0087] Existing technology: incoming material thickness 2.9mm; rolling thickness 0.495mm; total reduction rate 82.93%. Single-stand reversible rolling mill with 6 rolling passes.

[0088] This invention features: incoming material thickness of 3.1 mm; rolling thickness of 0.495 mm; total reduction rate of 84%; and a single-stand reversible rolling mill with 8 rolling passes.

[0089] 4. 50W1000 and 50W1300 grade steel.

[0090] Existing technology: incoming material thickness 2.9mm; rolling thickness 0.495mm; total reduction rate 82.93%; single-stand reversible rolling mill with 6 rolling passes.

[0091] This invention features: incoming material thickness of 3.1 mm; rolling thickness of 0.495 mm; total reduction rate of 84%; and a single-stand reversible rolling mill with 8 rolling passes.

[0092] V. Increase the strip tension in cold-rolled silicon steel mills:

[0093] 1. 50W470, 50W600, and 50W800 grade steel, 2.55mm thick, rolled to 0.495mm thick.

[0094] Existing technology: The back tension of the strip in the first pass is 37.81KN and the front tension is 87.24KN; the back tension of the strip in the second pass is 87.24KN and the front tension is 131KN; the back tension of the strip in the third pass is 131KN and the front tension is 183KN; the back tension of the strip in the fourth pass is 183KN and the front tension is 200KN; the back tension of the strip in the fifth pass is 200KN and the front tension is 60KN.

[0095] The present invention has the following characteristics: the post-rolling tension of the strip in the first pass is 40.62 kN and the pre-rolling tension is 95.71 kN; the post-rolling tension of the strip in the second pass is 95.71 kN and the pre-rolling tension is 143 kN; the post-rolling tension of the strip in the third pass is 143 kN and the pre-rolling tension is 196 kN; the post-rolling tension of the strip in the fourth pass is 196 kN and the pre-rolling tension is 215 kN; the post-rolling tension of the strip in the fifth pass is 215 kN and the pre-rolling tension is 143 kN; and the post-rolling tension of the strip in the sixth pass is 143 kN and the pre-rolling tension is 77 kN.

[0096] 2. 50W1000 and 50W1300 grade steel, 2.55mm thick, rolled to 0.495mm.

[0097] Existing technology: The post-rolling tension of the strip in the first pass is 35.21KN and the pre-rolling tension is 87.24KN; the post-rolling tension of the strip in the second pass is 87.24KN and the pre-rolling tension is 131KN; the post-rolling tension of the strip in the third pass is 131KN and the pre-rolling tension is 183KN; the post-rolling tension of the strip in the fourth pass is 183KN and the pre-rolling tension is 199KN; the post-rolling tension of the strip in the fifth pass is 199KN and the pre-rolling tension is 60KN.

[0098] The present invention has the following characteristics: the post-rolling tension of the strip in the first pass is 40.62 kN and the pre-rolling tension is 95.71 kN; the post-rolling tension of the strip in the second pass is 95.71 kN and the pre-rolling tension is 143 kN; the post-rolling tension of the strip in the third pass is 143 kN and the pre-rolling tension is 196 kN; the post-rolling tension of the strip in the fourth pass is 196 kN and the pre-rolling tension is 215 kN; the post-rolling tension of the strip in the fifth pass is 215 kN and the pre-rolling tension is 143 kN; and the post-rolling tension of the strip in the sixth pass is 143 kN and the pre-rolling tension is 77 kN.

[0099] 3. 50W800 grade steel. 2.9mm rolled to 0.495mm.

[0100] Existing technology: The tension after the first pass of strip rolling is 32.64KN, and the tension before the first pass is 73.55KN; the tension after the second pass of strip rolling is 73.55KN, and the tension before the first pass is 106KN; the tension after the third pass of strip rolling is 106KN, and the tension before the first pass is 146KN; the tension after the fourth pass of strip rolling is 146KN, and the tension before the first pass is 194KN; the tension after the fifth pass of strip rolling is 194KN, and the tension before the first pass is 200KN; the tension after the sixth pass of strip rolling is 200KN, and the tension before the first pass is 60KN.

[0101] The present invention specifies the following tensions for the strip after the first rolling pass: 40.2 kN and initial tension: 85.6 kN; after the second rolling pass: 85.6 kN and initial tension: 121 kN; after the third rolling pass: 121 kN and initial tension: 162 kN; after the fourth rolling pass: 162 kN and initial tension: 211 kN; after the fifth rolling pass: 211 kN and initial tension: 225 kN; after the sixth rolling pass: 225 kN and initial tension: 231 kN; after the seventh rolling pass: 231 kN and initial tension: 243 kN; and after the eighth rolling pass: 243 kN and initial tension: 87 kN.

[0102] 4. 50W1000 and 50W1300 grade steel, 2.9mm thick, rolled to 0.495mm.

[0103] Existing technology: The post-rolling tension of the strip in the first pass is 30.96KN and the pre-rolling tension is 73.55KN; the post-rolling tension of the strip in the second pass is 73.55KN and the pre-rolling tension is 106KN; the post-rolling tension of the strip in the third pass is 106KN and the pre-rolling tension is 146KN; the post-rolling tension of the strip in the fourth pass is 146KN and the pre-rolling tension is 194KN; the post-rolling tension of the strip in the fifth pass is 194KN and the pre-rolling tension is 200KN; the post-rolling tension of the strip in the sixth pass is 200KN and the pre-rolling tension is 60KN.

[0104] The present invention specifies the following parameters for the strip: First pass: post-rolling tension 40.2 KN, pre-rolling tension 85.6 KN; Second pass: post-rolling tension 85.6 KN, pre-rolling tension 121 KN; Third pass: post-rolling tension 121 KN, pre-rolling tension 162 KN; Fourth pass: post-rolling tension 162 KN, pre-rolling tension 211 KN; Fifth pass: post-rolling tension 211 KN, pre-rolling tension 225 KN; Sixth pass: post-rolling tension 225 KN, pre-rolling tension 231 KN; Seventh pass: post-rolling tension 231 KN, pre-rolling tension 243 KN; Eighth pass: post-rolling tension 243 KN, pre-rolling tension 87 KN.

[0105] VI. Balancing the reduction of sheet thickness variation in cold-rolled strip with the improvement of sheet shape

[0106] 1. Based on the difference in the same plate value of cold-rolled strip, a small correction is made in each of the first to fifth passes. If the correction is too large at one time, it will cause a large waviness, making rolling impossible.

[0107] 2. In the sixth and seventh passes, reduce the reduction rate per pass to adjust the plate shape.

[0108] 3. Taking the cold rolling production method of hot-rolled large wedge-shaped incoming material as an example, such as... Figure 3 As shown.

[0109] Large wedge-shaped feed refers to hot-rolled strip steel with one side thicker than the other in the width direction. To achieve a good strip shape, the upper roll must be positioned at the same 3° angle as the upper surface of the strip, but this is not conducive to reducing the thickness difference along the same thickness. If the upper roll is positioned parallel to the roll gap, the thickness difference along the same thickness can be significantly reduced, but a large waviness will appear on the higher side of the strip. In this situation, it is necessary to consider both reducing the thickness difference along the same thickness and achieving a good strip shape. This can be achieved by adjusting the roll inclination value:

[0110] In the first pass, the upper roll A side is pressed down by 4 micrometers more than the B side, and slight waviness is allowed on the left side after the strip is rolled out;

[0111] In the second pass, the upper roll A side is pressed down by 4 micrometers more than the B side, and slight waviness is allowed on the left side after the strip is rolled out;

[0112] In the third pass, the upper roll A side is pressed down by 4 micrometers more than the B side, and slight waviness is allowed on the left side after the strip is rolled out;

[0113] In the fourth pass, the upper roll A side is pressed down by 4 micrometers more than the B side, and slight waviness is allowed on the left side after the strip is rolled out;

[0114] In the fifth pass, the upper roll A side is pressed down by 4 micrometers more than the B side, and slight waviness is allowed on the left side after the strip is rolled out;

[0115] In the sixth and seventh passes, a small reduction rate is used, the upper and lower rollers are parallel, and the plate shape is adjusted.

[0116] If a unilateral waviness does not appear on the left side of the strip during the first to fifth rolling passes, the difference between the rolled strip and the sheet will not decrease.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of reducing transverse strip variation in a silicon steel product, characterized by, The method comprises the following steps: S1, increasing the original roll crown of the cold-rolled silicon steel rolling mill; S2, moving the upper and lower intermediate rolls of the cold-rolled silicon steel rolling mill, and determining the position of the axial movement of the upper and lower intermediate rolls according to the width of the strip steel; S3, adjusting the bending roll of the cold-rolled silicon steel rolling mill according to the rolling reduction rate: increasing the positive bending extension length of the bending roll of the cold-rolled silicon steel rolling mill; S4, increasing the total reduction rate of the cold-rolled silicon steel rolling mill; S5, increasing the strip steel tension of the cold-rolled silicon steel rolling mill; S6, reducing the same plate difference of the cold-rolled strip steel, and according to the numerical value of the same plate difference of the cold-rolled strip steel, the first pass to the Nth pass are corrected, and the reduction rate of each pass is reduced from the N+1th pass to the last pass to adjust the plate shape; wherein the value of N is determined according to different incoming materials; In step S2, the smaller the width of the strip steel, the greater the distance of the position of the left vertex of the upper intermediate roll moving to the right of the left vertex of the strip steel, and the greater the distance of the position of the right vertex of the lower intermediate roll moving to the left of the right vertex of the strip steel; the greater the width of the strip steel, the smaller the distance of the position of the left vertex of the upper intermediate roll moving to the right of the left vertex of the strip steel, and the smaller the distance of the position of the right vertex of the lower intermediate roll moving to the left of the right vertex of the strip steel; When the width of the strip steel is greater than 1200mm and less than 1500mm, the left vertex of the upper intermediate roll is at the position of 10mm left of the corresponding left vertex of the strip steel; the right vertex of the lower intermediate roll is at the position of 10mm right of the corresponding right vertex of the strip steel; When the width of the strip steel is greater than 1100mm and less than 1200mm, the left vertex of the upper intermediate roll is aligned with the left vertex of the strip steel; the right vertex of the lower intermediate roll is aligned with the right vertex of the strip steel; When the width of the strip steel is greater than 1000mm and less than 1100mm, the left vertex of the upper intermediate roll is at the position of 2mm right of the corresponding left vertex of the strip steel; the right vertex of the lower intermediate roll is at the position of 2mm left of the corresponding right vertex of the strip steel; When the width of the strip steel is greater than 800mm and less than 1000mm, the left vertex of the upper intermediate roll is at the position of 10mm right of the corresponding left vertex of the strip steel; the right vertex of the lower intermediate roll is at the position of 10mm left of the corresponding right vertex of the strip steel.

2. The method of reducing lateral strip variation of silicon steel product of claim 1, wherein, In step S1, the original roll crown of the cold-rolled silicon steel rolling mill is 50-60 microns.

3. The method of reducing strip profile variation in silicon steel products of claim 1 wherein, In step S3, when the total reduction rate of the cold-rolled silicon steel rolling mill is greater than 70% and less than 75%, the positive bending extension length is 18mm; When the total reduction rate of the cold-rolled silicon steel rolling mill is greater than 75% and less than 80%, the positive bending extension length is 26mm; When the total reduction rate of the cold-rolled silicon steel rolling mill is greater than 80% and less than 85%, the positive bending extension length is 34mm; When the total reduction rate of the cold-rolled silicon steel rolling mill is greater than 85% and less than 89%, the positive bending extension length is 45mm.

4. The method of reducing strip profile variation in silicon steel products of claim 1 wherein, In step S4, the total reduction rate is the percentage of the thickness of the incoming material before rolling minus the thickness after rolling to the thickness of the incoming material before rolling, and the total reduction rate satisfies the following formula: ε=(T1-T2)÷T1×100%, wherein ε is the total reduction rate, T1 is the thickness of the incoming material before rolling, and T2 is the thickness after rolling. The strip elongation coefficient is equal to the strip thickness difference before rolling divided by the strip thickness difference after rolling, and the strip elongation coefficient is the ratio of the strip thickness before rolling to the strip thickness after rolling, and the strip elongation coefficient satisfies the following formula: λ = T1 / T2 = Δ / δ, and δ = Δ / λ = 1 / (1-ε) is obtained, wherein Δ is the raw material strip thickness difference, and δ is the strip thickness difference after rolling; It is concluded that the greater the total reduction rate ε is, the greater the strip elongation coefficient λ is, and the smaller the strip thickness difference δ after rolling is; the strip width direction one-side large and the other-side small transverse strip thickness difference can be reduced by increasing the total reduction rate of the cold rolling silicon steel rolling mill, and the strip width direction middle-high and two-side-low transverse strip thickness difference can also be reduced.

5. The method of reducing strip transverse variability of silicon steel product of claim 1 or 4, wherein, In step S4, the mode of increasing the total reduction rate of the cold rolling silicon steel rolling mill comprises: S41, increasing the total reduction rate by increasing the raw material thickness under the condition that the rolling thickness is unchanged; S42, reducing the transmission load and the rolling pressure by increasing the rolling pass; S43, determining the raw material thickness according to different steel grades and rolling thicknesses.

6. The method of reducing strip profile variation of silicon steel product of claim 5, wherein, In step S5, the back tension and the front tension of the strip after each rolling pass are increased, and the back tension and the front tension of the increased rolling pass are set.

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