Working roll capable of reducing transverse thickness difference of cold-rolled strip steel and working method

Abstract

The invention provides a working roll capable of reducing the transverse thickness difference of cold-rolled strip steel and a working method, and relates to the technical field of cold rolling process.The middle position of a roll body of the working roll is provided with roll convexity, symmetrical strip steel edge thinning areas are arranged at the positions, corresponding to the two side edges of the strip steel, of the roll body, and small-diameter areas are formed; the diameter of the roller body corresponding to the strip steel edge thinning area is smaller than the diameter of the roller convexity in the middle of the roller body; wherein the strip steel edge thinning area is an extension area of the part of the strip steel width and the edge of the strip steel in the width direction and is used for counteracting the thickness difference caused by too high rolling pressure of the edge of the strip steel in the rolling process. According to the method, rolling mill equipment and rollers do not need to be transformed, and roller consumption of the rollers is not increased. The roll shape can be achieved through grinding of a grinding machine, and the transverse thickness difference of strip steel is smaller than 0.0068 mm.

Description

Technical Field

[0001] The present invention relates to the technical field of cold rolling processes, and in particular to a working roll and a working method for reducing the transverse thickness difference of cold-rolled strip steel. Background Art

[0002] The transverse thickness difference of the strip (the thickness difference of the same plate) is the difference between the maximum thickness and the minimum thickness in the width direction of the strip, expressed as δ h =H-h means, such as Figure 1 The common form of transverse thickness difference is that the thickness in the middle of the strip is larger and the thickness on both sides is smaller. Cold-rolled silicon steel products have very high requirements for transverse thickness difference, which is generally less than 0.007mm.

[0003] Due to the original transverse thickness difference of the hot-rolled strip steel used for cold rolling and the bending deformation caused by the rolling force applied to both ends of the working roll during the cold rolling process, such as Figure 2 As shown, it is difficult to achieve the requirement of less than 0.007mm. In order to reduce the transverse thickness difference, the existing technology generally adopts a six-roll cold rolling mill, which reduces the bending deformation of the working roll by axially shifting the position of the intermediate roll, such as Figure 3 As shown, the transverse thickness difference of the strip is reduced, but the actual effect is not significant, and the transverse thickness difference of the strip is between 0.008 and 0.012. "Steel" 2018 Issue 8 - "EVC-Plus Technology for Thickness Difference Control of Cold-rolled Non-oriented Silicon Steel - Li Guanghui" envisions using a vase-shaped roller in the initial rolling pass to roll the strip into a cross-sectional shape with two sides thicker than the rest of the strip, such as Figure 4 As shown, the bulges on both sides of the strip are eliminated in subsequent passes through the normal roller profile, and a rectangular section is rolled out, as shown in Figure 5 As shown in the figure, this method results in the strip edge's raised portion extending significantly more than the rest of the strip width during subsequent rolling passes, resulting in severe double-sided wave formation. Furthermore, all previous production units were designed with one side designated as the operating side and the other as the drive side. The drive mechanism for this vase-shaped work roll requires dual placement. If the upper roll's drive mechanism is on the right, the lower roll's must be on the left. This arrangement is not only unprecedented but also significantly increases the equipment footprint.

[0004] The present invention uses a special working roll profile to reduce the transverse thickness difference of the strip steel. Summary of the Invention

[0005] In response to the aforementioned technical problem that existing technologies cannot meet the requirement for a transverse thickness difference of less than 0.007mm for cold-rolled silicon steel products, a work roll and a method for reducing the transverse thickness difference of cold-rolled strip steel are provided. The present invention primarily utilizes a special work roll profile to reduce the transverse thickness difference of the strip steel.

[0006] The technical means adopted in the present invention are as follows:

[0007] A working roll for reducing the transverse thickness difference of cold-rolled strip, wherein a roll crown is provided in the middle position of the roll body of the working roll, and symmetrical strip edge thinning areas are provided at positions of the roll body corresponding to the edges of the strip on both sides to form small diameter areas, and the diameter of the roll body corresponding to the strip edge thinning areas is smaller than the roll crown diameter in the middle of the roll body; wherein the strip edge thinning areas are part of the strip width and the extension area of the edges in the width direction of the strip, and are used to offset the thickness difference caused by excessive rolling pressure at the strip edges during rolling.

[0008] Furthermore, the maximum distance L1 between the two small diameter areas of the working roll satisfies, L1 = B + 2 × b1, where B is the strip width, b1 is the reserved distance between the end point of the small diameter area of the working roll and the edge of the strip, and the end point of the small diameter area of the working roll is 10 mm outward from the position of the corresponding strip edge of the working roll, and the value of b1 is 10 mm.

[0009] Furthermore, the minimum distance L2 between adjacent strip edge thinning areas satisfies: L2 = B-2×b2, where b2 is the distance from the position of the corresponding strip edge of the working roll to the starting point of the small diameter zone of the working roll. The starting point of the small diameter zone of the working roll is 30 mm from the position of the corresponding strip edge of the working roll toward the center line of the working roll, and the value of b2 is 30 mm.

[0010] Furthermore, the convexity value of the roller convexity C is 0.06-0.12 mm, and the diameter reduction amount of the thinning area at the edge of the strip is 0.075 mm.

[0011] Furthermore, the minimum diameter d1 of the small diameter zone of the working roll satisfies: d1 = D - 2 x 0.075 mm, where D is the middle diameter of the working roll body.

[0012] The present invention also provides a working method for reducing the transverse thickness difference of cold-rolled strip steel, comprising the following steps:

[0013] Select the corresponding working rolls according to the strip width and install the working rolls into the rolling mill stand;

[0014] The first rolling pass uses the roll profile of the working roll, with a total reduction ratio of 30%; the second rolling pass uses the roll profile of the working roll, with a total reduction ratio of 30%; the third rolling pass uses the roll profile of the working roll, with a total reduction ratio of 25%; the fourth rolling pass uses the roll profile of the working roll, with a total reduction ratio of 15%, and the total reduction meets the target thickness requirement.

[0015] Furthermore, the reduction amount is calculated as follows: n-th pass reduction amount = difference between initial thickness and target thickness × n-th pass reduction ratio.

[0016] Furthermore, the strip edge thinning area is completely aligned with the strip edge during rolling, ensuring that the strip edge is located within the width b2 of the strip edge thinning area to reduce the edge rolling pressure.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] The method does not require the modification of rolling mill equipment and rollers, and does not increase roller wear. The roller profile of the present invention can be achieved by grinding on a grinder, and the transverse thickness difference of the strip is less than 0.0068 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative labor.

[0020] Figure 1 Schematic diagram of the transverse thickness difference of the strip.

[0021] Figure 2 Schematic diagram of the bending deformation caused by the rolling force at both ends of the existing working roll.

[0022] Figure 3 This is a schematic diagram of the existing technology using a six-roll cold rolling mill to reduce the bending deformation of the working rolls by axially shifting the position of the intermediate rolls.

[0023] Figure 4 The present invention is a schematic diagram of a vase-shaped roller used in the rolling passes in the prior art.

[0024] Figure 5 This is a schematic diagram of the conventional technology of eliminating the bulges on both sides of the strip in subsequent passes using a normal roller profile.

[0025] Figure 6 It is a schematic diagram of the working roll profile of the present invention.

[0026] Figure 7 This is a schematic diagram of the roll-type upper and lower working rolls of the present invention in the non-pressing state.

[0027] In the figure: 1. Roller body; 2. Strip steel; 3. Thinning area at the edge of the strip steel. DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] Unless otherwise specified, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments can have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0032] like Figure 6-7 As shown, the present invention provides a working roll for reducing the transverse thickness difference of cold-rolled strip steel, wherein a roll crown is provided in the middle position of a roll body 1 of the working roll, and symmetrical strip edge thinning areas 3 are provided at positions of the roll body 1 corresponding to the edges of the strip steel 2 on both sides thereof, forming a small diameter area, and the diameter of the roll body 1 corresponding to the strip edge thinning area 3 is smaller than the roll crown diameter in the middle of the roll body 1; wherein the strip edge thinning area 3 is an extension area of part of the width of the strip steel 2 and the edge of the strip steel 2 in the width direction, and is used to offset the thickness difference caused by excessive rolling pressure at the edge of the strip steel 2 during rolling.

[0033] Furthermore, the maximum distance L1 between the two small diameter areas of the working roll satisfies, L1 = B + 2 × b1, where B is the width of the strip 2, b1 is the reserved distance between the end point of the small diameter area of the working roll and the edge of the strip 2, and the end point of the small diameter area of the working roll is 10 mm outward from the position of the working roll corresponding to the edge of the strip 2, and the value of b1 is 10 mm.

[0034] Furthermore, the minimum distance L2 between adjacent strip edge thinning areas 3 satisfies: L2 = B-2×b2, wherein b2 is the distance from the position of the corresponding strip 2 edge of the working roll to the starting point of the small diameter zone of the working roll, and the starting point of the small diameter zone of the working roll is the position 30 mm in the direction of the center line of the working roll from the position of the corresponding strip 2 edge of the working roll, and the value of b2 is 30 mm.

[0035] Furthermore, the roll crown C satisfies the following equation: C=D−d, where D is the middle diameter of the work roll barrel 1 , d is the diameter at both ends of the work roll barrel 1 , and C represents the roll crown.

[0036] Furthermore, the convexity value of the roller convexity C is 0.06-0.12 mm, and the diameter reduction of the thinning area 3 at the edge of the strip is 0.075 mm.

[0037] Furthermore, the minimum diameter d1 of the small diameter zone of the working roll satisfies: d1 = D - 2 × 0.075 mm, where D is the middle diameter of the working roll body 1 .

[0038] The present invention also provides a working method for reducing the transverse thickness difference of a cold-rolled steel strip 2, comprising the following steps:

[0039] Select corresponding working rolls according to the width of the strip 2 and install the working rolls into the rolling mill stand;

[0040] The first rolling pass uses the roll profile of the working roll, with a total reduction ratio of 30%; the second rolling pass uses the roll profile of the working roll, with a total reduction ratio of 30%; the third rolling pass uses the roll profile of the working roll, with a total reduction ratio of 25%; the fourth rolling pass uses the roll profile of the working roll, with a total reduction ratio of 15%, and the total reduction meets the target thickness requirements.

[0041] Furthermore, the reduction amount is calculated as follows: n-th pass reduction amount = difference between initial thickness and target thickness × n-th pass reduction ratio.

[0042] Furthermore, the edge thinning region 3 of the strip is completely aligned with the edge of the strip 2 during rolling, ensuring that the edge of the strip 2 is within the width b2 of the edge thinning region 3 of the strip, so as to reduce the edge rolling pressure.

[0043] Example 1:

[0044] like Figure 6-7 As shown, the present invention provides a working roll for reducing the transverse thickness difference of cold-rolled strip steel, comprising:

[0045] 1. Determination of the roll crown of the working roll

[0046] L is the length of the roll barrel 1, which is generally 20 to 40 mm greater than the maximum strip width 2 specified in the product outline. D is the center diameter of the work roll barrel 1, and d is the end diameter of the work roll barrel 1. C represents the roll crown, which is C = D - d. The C value generally ranges from 0.06 to 0.12 mm. Because silicon steel products have very high requirements for transverse thickness difference, the roll crown value used in this method is 0.1 mm.

[0047] 2. Determination of the thinning area of the strip 2 edge

[0048] Figure 6 Where B is the width of the rolled strip 2. b2 is the thinning area of the strip 2. According to the quality statistical data, the thinning range of the strip 2 edge is 25-30 mm. Therefore, the length of the thinning area of the strip 2 is determined to be 30 mm.

[0049] 3. Determination of the starting point of the small diameter area of the working roll

[0050] The starting point of the small diameter area of the working roll is 30 mm from the edge of the working roll to the center line of the working roll. Figure 6 point f).

[0051] 4. Determination of the end point of the small straight zone of the working roll

[0052] The end point of the small diameter zone of the working roll is 10 mm outside the edge of the corresponding strip 2 of the working roll. Figure 6 The function of b1 is to leave a certain margin for the possible width deviation and left and right lateral movement of the strip 2.

[0053] 5. Determination of the minimum diameter of the small diameter area of the working roll and the position of the minimum diameter point

[0054] The roller surface position corresponding to the end point x of the small diameter area is the minimum diameter point position, and the minimum diameter d1 = D-2×0.075mm. That is, the convexity of the minimum diameter point in the small diameter area is -0.075mm.

[0055] 6. Determination of the maximum distance between the two minimum diameter areas of the working roll

[0056] Figure 6 The length of L1 is L1 = B + 2 × b1. L1 is used to determine the grinding endpoint of the work roll. In this method, L1 of the upper work roll must be equal to L1 of the lower work roll.

[0057] 7. Determination of the minimum distance between the two minimum diameter areas of the working roll

[0058] Figure 6 The length of L2 is L2 = B - 2 × b2. L2 is used to determine the starting point of grinding for the work roll. In this method, L2 of the upper work roll must be equal to L2 of the lower work roll.

[0059] 8. The role of the small diameter area of the working roll

[0060] Figure 6 Starting from point f, the closer to the edge of the strip, the larger the opening between lines fx and fe, and the smaller the rolling pressure during rolling. The angle between lines fx and fe decreases during rolling, thus offsetting the effect of roll bending deformation.

[0061] 9. Preparation Roll of This Method

[0062] Since L1=B+2×b1, the width of the strip 2 is different, so L1 is different. Therefore, for strips 2 of different widths, different L1 spare rolls are required, and they cannot be universal. When the width of the strip 2 before rolling by the working roll A is 1200mm, then L1=1200mm+2×10mm=1220mm; L2=1200mm-2×30mm=1140mm. When the width of the next roll of strip 2 is 1100mm, it is still rolled by the working roll A. Then, the entire width of the next roll of strip 2 is within the L2 range of the A roll, and the two edges of the strip 2 are not covered by the small diameter area corresponding to the A roll b2. Therefore, corresponding to the several width specifications commonly produced, several groups of corresponding spare rolls must be separated. For example, a factory usually produces several strip 2 width specifications and the corresponding spare roll groups:

[0063] There are three pairs of working rolls in group A. The width of the strip 2 corresponding to group A is 1100 mm: group A working roll L1 = 1100 mm + 2 × 10 mm = 1120 mm. Group A working roll L2 = 1100 mm - 2 × 30 mm = 1040 mm.

[0064] There are three pairs of working rolls in group B. The width of the strip 2 corresponding to group B is 1200 mm: group B L1 = 1200 mm + 2 × 10 mm = 1220 mm. Group B L2 = 1200 mm - 2 × 30 mm = 1140 mm.

[0065] There are 3 pairs of working rolls in group C, and the width of the strip steel 2 corresponding to the working rolls in group C is 1300mm: working roll group C L1 = 1300mm + 2×10mm = 1320mm; working roll group C L2 = 1300mm - 2×30mm = 1240mm.

[0066] After the rolls of group A have rolled a strip steel 2 with a width of 1100mm, the width of the new strip steel 2 is changed to 1200mm. The upper and lower working rolls of group A must be pulled out from the rolling mill frame, and then the upper and lower working rolls of group B must be installed into the rolling mill frame.

[0067] 10. Reduction ratio of each rolling pass in this method

[0068] 1. Because the roll profile of the working roll of this method has a strong ability to resist roll bending deformation and edge rolling pressure, the roll profile of the working roll of this method is used in the first rolling pass of this method, and the total reduction ratio is 30%.

[0069] 2. Because the roll profile of the working roll of this method has a strong ability to resist roll bending deformation and edge rolling pressure, the roll profile of the working roll of this method is used in the second rolling pass of this method, and the total reduction ratio is 30%.

[0070] 3. Because the roll profile of the working roll of this method has a strong ability to resist roll bending deformation and edge rolling pressure, the roll profile of the working roll of this method is used in the third rolling pass of this method, and the total reduction ratio is 25%.

[0071] 4. Because the roll profile of the working roll of this method has a strong ability to resist roll bending deformation and edge rolling pressure, the roll profile of the working roll of this method is used in the fourth rolling pass of this method, and the total reduction ratio is 15%.

[0072] 11. The reduction of each rolling pass of 3.0mm thickness rolling to 0.9mm thickness rolling in this method

[0073] 1. The first rolling pass has a reduction ratio of 30%. Reduction = (3-0.9) x 30% = 0.63 mm.

[0074] 2. The second rolling pass has a reduction ratio of 30%. Reduction = (3-0.9) x 30% = 0.63 mm.

[0075] 3. The third rolling pass has a reduction ratio of 25%. Reduction = (3-0.9) x 25% = 0.525 mm.

[0076] 4. The fourth rolling pass has a reduction ratio of 15%. Reduction = (3-0.9) x 15% = 0.315 mm.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 work roll for reducing transverse thickness difference of cold-rolled strip, characterized in that: The working roll is provided with a roll crown in the middle of the roll body, and symmetrical strip edge thinning areas are provided at positions of the roll body corresponding to the edges of the strip on both sides to form a small diameter area. The diameter of the roll body corresponding to the strip edge thinning area is smaller than the roll crown diameter in the middle of the roll body; wherein, the strip edge thinning area is an extension area of part of the strip width and the edge in the width direction of the strip, which is used to offset the thickness difference caused by excessive rolling pressure on the strip edge during rolling.

2. The work roll for reducing transverse thickness difference of cold-rolled strip according to claim 1, characterized in that: The maximum distance L1 between the two small diameter areas of the working roll satisfies, L1 = B + 2 × b1, where B is the strip width, b1 is the reserved distance between the end point of the small diameter area of the working roll and the edge of the strip, and the end point of the small diameter area of the working roll is 10 mm outward from the position of the corresponding strip edge of the working roll, and the value of b1 is 10 mm.

3. The work roll for reducing transverse thickness difference of cold-rolled strip according to claim 2, characterized in that: The minimum distance L2 between adjacent strip edge thinning areas satisfies: L2 = B-2×b2, where b2 is the distance from the position of the corresponding strip edge of the working roll to the starting point of the small diameter zone of the working roll. The starting point of the small diameter zone of the working roll is 30 mm from the position of the corresponding strip edge of the working roll toward the center line of the working roll, and the value of b2 is 30 mm.

4. The work roll for reducing transverse thickness difference of cold-rolled strip according to claim 3, characterized in that: The convexity value of the roller convexity C is 0.06-0.12 mm, and the diameter reduction amount of the thinning area at the edge of the strip is 0.075 mm.

5. The work roll for reducing transverse thickness difference of cold-rolled strip according to claim 4, characterized in that: The minimum diameter d1 of the small diameter zone of the working roll satisfies: d1 = D - 2 × 0.075 mm, where D is the middle diameter of the working roll body.

6. A method for reducing transverse thickness difference of cold-rolled strip working rolls, based on the method for reducing transverse thickness difference of cold-rolled strip working rolls according to any one of claims 1 to 5, characterized in that: The following steps are involved: Select the corresponding working rolls according to the strip width and install the working rolls into the rolling mill stand; The first rolling pass uses the roll profile of the working roll, with a total reduction ratio of 30%; the second rolling pass uses the roll profile of the working roll, with a total reduction ratio of 30%; the third rolling pass uses the roll profile of the working roll, with a total reduction ratio of 25%; the fourth rolling pass uses the roll profile of the working roll, with a total reduction ratio of 15%, and the total reduction meets the target thickness requirement.

7. The method for reducing the transverse thickness difference of cold-rolled strip according to claim 6, characterized in that: The calculation method of the pressing amount is: the pressing amount of the nth pass = the difference between the initial thickness and the target thickness × the pressing ratio of the nth pass.

8. The method for reducing transverse thickness difference of cold-rolled strip according to claim 6, characterized in that: The strip edge thinning area is completely aligned with the strip edge during rolling, ensuring that the strip edge is located within the width b2 of the strip edge thinning area to reduce the edge rolling pressure.

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