A work roll profile design method for improving the warping section profile defect of the strip edge

Abstract

The present invention provides a working roll profile design method for improving the warping cross-sectional profile defect at the edge of a plate and strip, and belongs to the field of rolling automation technology. The method uses a rolling roll profile measuring instrument to measure the working roll profile three times to obtain the hot roll profile curve of the working roll. First, the roll profile A of the working roll on the machine before rolling is measured. Secondly, the roll profile B of the working roll just off the machine after rolling is measured. Finally, the roll profile C of the working roll after cooling to room temperature is measured. The hot roll profile curve is obtained by subtracting the roll profile B from the roll profile C. The original comprehensive roll profile is obtained by superimposing the hot roll profile curve with the roll profile A. Based on the amplitude of the middle position of the original comprehensive roll profile curve, a target curve of a new comprehensive roll profile in the form of a parabola is formulated. The designed target curve of the new comprehensive roll profile is subtracted from the hot roll profile curve to obtain a new grinding roll profile curve. The present invention can effectively improve the warping plate profile defect at the edge of the plate and strip and improve the quality of the finished plate profile.

Description

Technical Field

[0001] The present invention relates to the technical field of rolling automation, and in particular to a working roll profile design method for improving the warping section profile defect of a plate and strip edge. Background Art

[0002] Shape is an important factor that needs to be paid attention to in the production of hot rolled strip, which directly affects product quality and production stability. Cross-sectional profile is the key indicator of shape control and is the focus of existing control models and roll profile technology. Despite decades of development, as rolling mills become wider and wider, the width of the strip produced becomes wider and the thickness of the strip becomes thinner, some special shape problems have emerged that have not yet been solved, such as edge warping (see attached). Figure 2 ). The local warping at the edge can easily lead people to suspect that it is caused by uneven roll wear. However, from the on-site tracking situation, the edge warping appears in the early stage of rolling, when the roll wear is still very small, and the peak of the cat's ear formed by uneven roll wear is often located 100-200mm away from the edge of the plate and strip. From the perspective of shape characteristics, it does not belong to the same type of problem as edge warping. Figure 3 Therefore, the control method of edge warping is still not so clear and deserves to be studied to obtain a smoother strip cross-section profile.

[0003] The most commonly used working roll shapes today are parabolic and continuously variable crown (CVC). The CVC roll shape can be modified by shifting the rolls, but the roll gap shape formed by different shifting roll positions is still parabolic, meaning the roll gap shape formed by the current mainstream roll shape is parabolic. The roll gap shape formed by thermal expansion of the rolls is bathtub-shaped, almost flat in the middle where it contacts the strip, but drops sharply at the edges due to the rapid transition in roll temperature. When the parabolic original roll gap shape and the bathtub-shaped hot roll gap shape are superimposed, a high-order curve is formed, which is the direct cause of edge warping. To compensate for the effects of the hot roll shape, the corresponding original ground roll shape can be reverse-engineered to eliminate this plate shape defect. Summary of the Invention

[0004] The present invention provides a work roll profile design method for improving the warping section profile defect of the strip edge. The method uses a roll profile measuring instrument to measure the work roll profile three times to obtain a thermal roll profile curve of the work roll.

[0005] In order to solve the above-mentioned purpose of the invention, the technical solution provided by the present invention is as follows:

[0006] A method for designing a work roll profile for improving a warped section profile defect at a strip edge comprises the following steps:

[0007] S1. Before the roll is put into the mill, the roll shape is measured over the entire length of the roll using a roll shape measuring instrument to obtain the original grinding roll shape curve A;

[0008] S2. After rolling is completed, the working roll is pulled out from the stand, and then the roll shape is measured over the entire length of the roll body using a roll shape measuring instrument to obtain a roll shape curve B that is a superposition of the original ground roll shape, the hot roll shape, and the worn roll shape;

[0009] S3. After the roll has cooled to room temperature, the roll shape is measured over the entire length of the roll using a roll shape measuring instrument to obtain a roll shape curve C that is a superposition of the original grinding roll shape curve and the worn roll shape curve;

[0010] S4, subtracting the roller profile curve B from the roller profile curve C to obtain a thermal roller profile curve;

[0011] S5, adding the hot roll profile curve to the original grinding roll profile curve A to obtain the original comprehensive roll profile curve;

[0012] S6. Based on the original comprehensive roll shape curve, a new comprehensive roll shape target curve in the form of a parabola is formulated;

[0013] S7. Subtract the target curve of the new comprehensive roll shape in S6 from the thermal roll shape curve to obtain a new grinding roll shape curve that compensates for the influence of the thermal roll shape.

[0014] The step S6 is specifically as follows:

[0015] Using the coordinate values ​​A (x1, y1) of the starting position of the original integrated roll curve, the coordinate values ​​B (x2, y2) of the middle position, and the coordinate values ​​C (x3, y3) of the end position, a quadratic polynomial curve is used to fit the target curve of the new integrated roll shape in the form of a parabola. The formula is as follows:

[0016] y=ax 2 +bx+c

[0017] Substituting the coordinate values ​​of points A(x1,y1), B(x2,y2), and C(x3,y3) into the formula can obtain the coefficients a, b, and c of the quadratic polynomial.

[0018] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0019] This approach develops a parabolic target roll profile based on the size and distribution of the hot roll profile. This creates an original roll profile that compensates for the effects of the hot roll profile, effectively preventing strip edge warping. This approach can be used to design the roll profile of each hot finish rolling mill stand, further ensuring a superior cross-section of the final product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 Schematic diagram of the original roll shape design for compensating for the influence of thermal roll shape in a work roll shape design method for improving the warping cross-sectional profile defect of a strip edge according to the present invention;

[0022] Figure 2 Schematic diagram of edge warping;

[0023] Figure 3 Schematic diagram of typical cross-section problems and ideal cross-section;

[0024] Figure 4 Schematic diagram of the comprehensive roll gap shape change in an embodiment of the present invention;

[0025] Figure 5 Schematic diagram of the change in the roller gap shape in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of 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. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The present invention provides a method for designing the profile of a work roll to improve the warping profile defect of a strip edge. The method comprises the following steps:

[0028] S1. Before the roll is put into the mill, the roll shape is measured over the entire length of the roll using a roll shape measuring instrument to obtain the original grinding roll shape curve A;

[0029] S2. After rolling is completed, the working roll is pulled out from the stand, and then the roll shape is measured over the entire length of the roll body using a roll shape measuring instrument to obtain a roll shape curve B that is a superposition of the original ground roll shape, the hot roll shape, and the worn roll shape;

[0030] S3. After the roll has cooled to room temperature, the roll shape is measured over the entire length of the roll using a roll shape measuring instrument to obtain a roll shape curve C that is a superposition of the original grinding roll shape curve and the worn roll shape curve;

[0031] S4, subtracting the roller profile curve B from the roller profile curve C to obtain a thermal roller profile curve;

[0032] S5, adding the hot roll profile curve to the original grinding roll profile curve A to obtain the original comprehensive roll profile curve;

[0033] S6. According to the amplitude of the middle position of the original comprehensive roll shape curve, a target curve of a new comprehensive roll shape in the form of a parabola is formulated;

[0034] S7. Subtract the target curve of the new comprehensive roll shape in S6 from the thermal roll shape curve to obtain a new grinding roll shape curve that compensates for the influence of the thermal roll shape.

[0035] The following describes this with reference to specific embodiments.

[0036] Taking a 2550mm hot rolling mill as an example, the last stand was selected for calculation. The stand used a parabolic work roll profile curve. The changes in the composite roll profile and the resulting roll gap shape after the superposition of the original roll profile and the hot roll profile in a rolling plan containing 60 identical strips were analyzed. When the original roll profile is a parabolic curve, the composite roll profile at the beginning of rolling is almost parabolic. As the number of rolling blocks increases, the hot roll profile increases, and the composite roll profile becomes a complex high-order curve, such as Figure 4 At the same time, the roll gap shape within the width of the strip gradually changes from a parabolic form to an edge warping form, as shown in Figure 5 As shown, it can be seen that the high-order composite roll shape leads to the warping of the strip edge.

[0037] According to the content of this invention, a grinding roll shape that compensates for the influence of thermal roll shape is designed. The specific steps are as follows:

[0038] The roll profile measuring instrument is used to measure the working roll of the last stand three times at different times, and the roll thermal profile curve is obtained:

[0039] 1) First measurement: Before the roll is put on the machine, the roll shape is measured over the entire length of the roll body using a roll shape measuring instrument to obtain the original grinding roll shape curve A (data see Appendix 1).

[0040] 2) Second measurement: After rolling is completed, the working roll is pulled out from the stand, and then the roll shape is measured over the entire length of the roll body using a roll shape measuring instrument to obtain the roll shape curve B which is the superposition of the original ground roll shape, the hot roll shape and the worn roll shape (data see Appendix 1).

[0041] 3) The third measurement: After the roll has cooled to room temperature, the roll shape is measured over the entire length of the roll using a roll shape measuring instrument to obtain a roll shape curve C that is a superposition of the original grinding roll shape curve and the worn roll shape curve (data are shown in Appendix 1).

[0042] 4) Subtract the second measured roller shape curve B from the third measured curve C (data see Appendix 1) to obtain the thermal roller shape curve, as shown in the attached table. Figure 1 Middle curve ②.

[0043] 5) Add the hot roller profile curve to the original grinding roller profile curve A obtained by the first measurement (data see Appendix 1) to obtain the original comprehensive roller profile curve.

[0044] 6) According to the original comprehensive roll shape curve, formulate the target curve of the new comprehensive roll shape in the form of a parabola, as shown in the attached figure. Figure 1 Middle curve ① to ensure the smoothness of the comprehensive roller curve.

[0045] Specific implementation process: Use the coordinate value A (-1425, 0) of the starting position of the original comprehensive roll shape curve, the coordinate value B (0, -137.34) of the middle position, and the coordinate value C (1425, -0.0036) of the end position, and use the quadratic polynomial curve to fit the target curve of the new comprehensive roll shape in the form of a parabola. The formula is as follows:

[0046] y=0.000068x 2 -0.000339x-137.34

[0047] Wherein a=0.000068, b=-0.00039, c=-137.34.

[0048] 7) By subtracting the target curve of the designed new comprehensive roll shape from the thermal roll shape curve (data see Appendix 1), the new grinding roll shape curve that compensates for the influence of thermal roll shape can be obtained, as shown in the attached table. Figure 1 Middle curve ③.

[0049] Appendix 1 Data of discrete points on the transverse direction of the work roll

[0050]

[0051]

[0052] 8) The new roller curve data obtained is submitted to the grinder, and after grinding on the machine, it is applied to the production site, effectively solving the problem of plate and strip edge warping when producing plates and strips on this production line, and achieving good application results.

[0053] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for designing the profile of a work roll for improving the warping section profile defect of a strip edge, characterized in that: The steps are as follows: S1. Before the roll is put into the mill, the roll shape is measured over the entire length of the roll using a roll shape measuring instrument to obtain the original grinding roll shape curve A; S2. After rolling is completed, the working roll is pulled out from the stand, and then the roll shape is measured over the entire length of the roll body using a roll shape measuring instrument to obtain a roll shape curve B that is a superposition of the original ground roll shape, the hot roll shape, and the worn roll shape; S3. After the roll has cooled to room temperature, the roll shape is measured over the entire length of the roll using a roll shape measuring instrument to obtain a roll shape curve C that is a superposition of the original grinding roll shape curve and the worn roll shape curve; S4, subtracting the roller profile curve B from the roller profile curve C to obtain a thermal roller profile curve; S5, adding the hot roll profile curve to the original grinding roll profile curve A to obtain the original comprehensive roll profile curve; S6. Based on the original comprehensive roll shape curve, a new comprehensive roll shape target curve in the form of a parabola is formulated; S7. Subtract the target curve of the new comprehensive roll shape in S6 from the thermal roll shape curve to obtain a new grinding roll shape curve that compensates for the influence of the thermal roll shape.

2. The work roll profile design method for improving the warping section profile defect of the strip edge according to claim 1 is characterized in that: The step S6 is specifically as follows: Using the coordinate values ​​A (x1, y1) of the starting position of the original integrated roll curve, the coordinate values ​​B (x2, y2) of the middle position, and the coordinate values ​​C (x3, y3) of the end position, a quadratic polynomial curve is used to fit the target curve of the new integrated roll shape in the form of a parabola. The formula is as follows: y=ax 2 +bx+c Substituting the coordinate values ​​of points A(x1,y1), B(x2,y2), and C(x3,y3) into the formula can obtain the coefficients a, b, and c of the quadratic polynomial.

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