A variable crown work roll profile with the ability to control edge-middle composite waves

Abstract

The present invention provides a continuously variable crown work roll profile for strip rolling with the ability to control edge-middle composite waves. This work roll profile consists of two parts: a trigonometric function and a quartic polynomial. The trigonometric function part mainly controls simple waves such as edge waves and center waves during strip rolling by forming a quadratic crown roll gap change. The quartic polynomial part mainly controls the edge-middle composite waves during strip rolling by forming a quartic crown roll gap. Using the work roll profile provided by the present invention, the problem of edge-middle composite waves during the rolling of different-width strips can be effectively solved, and the improvement of the shape control ability of the rolling mill can be achieved.

Description

Technical Field

[0001] The present invention relates to a roll profile of a variable crown work roll with the ability to control edge-middle combined waves, belonging to the technical field of strip shape control in strip rolling. Background Art

[0002] The shape control of hot-rolled strip steel is a hot topic of research at home and abroad. Under the condition that the rolling mill type and other factors are determined, the roll profile is the most direct and active factor in shape control. The roll profile forms a roll gap shape with a certain crown to achieve the purpose of shape control.

[0003] Currently, the relatively commonly used variable crown work roll is the CVC roll profile technology, which first appeared in the late 1970s and was developed by SMS of Germany. The upper and lower work rolls are ground into a specific "S" - shaped roll profile and arranged anti - symmetrically. By separately reversing the shifting of the upper and lower work rolls, the crown of the roll gap is changed to achieve the purpose of variable crown, so as to carry out shape control. The CVC roll profile can be expressed as:

[0004] R(x) = R0 + a1x + a2x 2 + a3x 3 .

[0005] Although this roll profile has a relatively simple design and the secondary crown is linearly related to the roll shifting amount, it only has the ability to control edge waves and middle waves through the secondary crown, and does not have the ability to control complex wave shapes such as edge - middle combined waves. Moreover, the secondary crown regulation ability is proportional to the square of the strip width. As the strip width decreases, the secondary crown control ability drops rapidly. Summary of the Invention

[0006] In order to solve the problem of controlling edge - middle combined waves, based on a full study of the principle of the existing variable crown work roll profile, the present invention provides a roll profile of a variable crown work roll with the ability to control edge - middle combined waves.

[0007] The technical solution of the present invention is: a roll profile of a variable crown work roll with the ability to control edge - middle combined waves, characterized in that: the roll profile curve of the work roll adopts the function shown in Formula I:

[0008]

[0009] In the formula, Y(x): the roll profile function of the work roll, with the unit of mm;

[0010] x: the roll body coordinate, with the unit of mm, and the range is [0, L];

[0011] A: the amplitude of the roll profile, with the unit of mm;

[0012] B: the offset of the roll profile, with the unit of mm;

[0013] L: Roll body length, unit: mm;

[0014] C: Roll profile slope, unitless;

[0015] D: Control coefficient of compound edge and center wave of roll profile, unit: mm;

[0016] E: Control coefficient of compound edge and center wave of roll profile, unit: mm -2 ;

[0017] F: Control coefficient of compound edge and center wave of roll profile, unit: mm -3 .

[0018] Furthermore: Given the roll body length L of the work roll, the shifting stroke [-S m , S m , and the range of secondary crown regulation [C w1 , C w2 , the roll profile parameters A and B can be determined by Equations II and III:

[0019]

[0020] In the equations, S m : Extreme shifting position of the work roll, unit: mm;

[0021] C w1 : Secondary crown of the roll gap when the work roll is at the shifting position -S m , unit: mm;

[0022] C w2 : Secondary crown of the roll gap when the work roll is at the shifting position S m , unit: mm.

[0023] Furthermore: According to the control requirements of the compound edge and center wave, given the fourth-order crown C h , the control coefficients D, E, and F of the compound edge and center wave of the roll profile can be determined by Equations IV, V, and VI:

[0024]

[0025] E = -2FL V

[0026]

[0027] In the equations, C h : Magnitude of the fourth-order crown, negative value, unit: mm.

[0028] Furthermore: The roll profile slope C can be determined by Equation VII:

[0029]

[0030] W: The most common rolling width of the strip steel, in mm.

[0031] Furthermore: For strip steels with different widths, the synchronous adjustment of the reduction amounts at the edges and in the middle in the width direction of the strip steel can be achieved by the positive shifting of the rolls, improving the edge-middle composite waviness.

[0032] The advantages of the present invention are as follows. By adopting the variable crown work roll profile with the ability to control the edge-middle composite wave, the problem that the conventional variable crown work roll profile cannot adjust the edge-middle composite wave in combination with the actual production needs on site can be solved, and the ability to control the edge-middle composite wave can be achieved while controlling the conventional middle wave and edge wave. By using the roll profile provided by the present invention, the edge-middle composite wave problem occurring during strip steel rolling can be significantly improved. Brief Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the variable crown work roll profile technology.

[0034] Figure 2 It is a schematic diagram of the specific work roll profile of the present invention.

[0035] Figure 3 It is a schematic diagram of the four-time crown roll gap of the roll profile of the present invention.

[0036] Figures 4(a), 4(b), and 4(c) are respectively schematic diagrams of the roll gap comparison between the conventional roll profile and the roll profile of the present invention at different roll shifting positions.

[0037] Figures 5(a), 5(b), and 5(c) are respectively the roll gap shapes of the conventional roll profile (roll shifting position is -150 mm) and the roll profile of the present invention (roll shifting position is -120 mm) when the strip steel width is 2500 mm, and the roll gap difference between the two.

[0038] Figures 6(a), 6(b), and 6(c) are respectively the roll gap shapes of the conventional roll profile (roll shifting position is -150 mm) and the roll profile of the present invention (roll shifting position is -120 mm) when the strip steel width is 3100 mm, and the roll gap difference between the two.

[0039] Figures 7(a), 7(b), and 7(c) are respectively the roll gap shapes of the conventional roll profile (roll shifting position is 100 mm) and the roll profile of the present invention (roll shifting position is 130 mm) when the strip steel width is 2500 mm, and the roll gap difference between the two.

[0040] Figures 8(a), 8(b), and 8(c) are respectively the roll gap shapes of the conventional roll profile (roll shifting position is 100 mm) and the roll profile of the present invention (roll shifting position is 130 mm) when the strip steel width is 3100 mm, and the roll gap difference between the two. Detailed Embodiment

[0041] The present invention provides a work roll profile with variable crown and the ability to control edge-middle combined waves as shown in Formula I. The upper and lower work roll profiles are arranged anti-symmetrically, as Figure 1 shown, which can achieve the control of common middle waves and edge waves while having the ability to control edge-middle combined waves.

[0042]

[0043] Among them, the design scheme of this roll profile is as follows: Given the work roll body length L and the roll shifting stroke [-S m , S m , and on the premise of obtaining the secondary crown regulation range [C w1 , C w2 by combining the actual production situation on site, in the first step, the roll profile offset B is obtained from Formula II; in the second step, the roll profile amplitude A is obtained from Formula III; in the third step, the fourth-order crown C h is given by combining the actual production situation on site, and the edge-middle combined wave control coefficients F, E, and D of the roll profile are obtained from Formulas IV, V, and VI in sequence; in the fourth step, the roll profile slope C is obtained from Formula VII, and the designed roll profile is as Figure 2 shown.

[0044]

[0045] E = -2FL V

[0046]

[0047] Figure 3 is the roll gap shape of the fourth-order crown component in the roll profile of the present invention. During the actual rolling process, there are obvious differences between the roll profile of the present invention and the roll gap shape of the conventional variable crown work roll profile under the condition of forming the same roll gap secondary crown, as shown in Figure 4 (i.e., Figure 4(a), Figure 4(b), Figure 4(c), the same below).

[0048] Furthermore, as shown in Figures 5, 6, 7, and 8, during the actual rolling process, for strip steels of different widths, when controlling the edge waves of the strip steel through positive roll shifting, compared with the conventional variable crown roll profile, it is possible to reduce the central reduction, thereby alleviating the middle wave, that is, realizing the synchronous adjustment of the reduction amounts at the edge and in the middle in the width direction of the strip steel, achieving the beneficial effect of improving the edge-middle combined wave shape.

[0049] Embodiment

[0050] The technical solution of the present invention will be further described below in conjunction with a specific embodiment of a 3800 mm rolling mill.

[0051] Given that the work roll body length L = 4100 mm and the work roll shifting stroke [-S m , S m= [-150 mm, 150 mm], the rolling width of the strip is taken as the normal rolling width on site, which is 3400 mm, and the required secondary crown control ability is [0.7 mm, -0.7 mm]. In the first step, the roll profile offset B is obtained from Equation II:

[0052]

[0053] In the second step, the roll profile amplitude A is obtained from Equation III:

[0054]

[0055] In the third step, combined with the actual production situation on site, the edge - center composite wave existing on site is controlled, and the fourth - order crown C h = -0.05 mm (as Figure 3 shown), and the roll profile edge - center composite wave control coefficient F is obtained from Equation IV:

[0056]

[0057] The roll profile edge - center composite wave control coefficient E is obtained from Equation V:

[0058] E = -2FL = 6.19066×10 -11

[0059] The roll profile edge - center composite wave control coefficient D is obtained from Equation VI:

[0060]

[0061] In the fourth step, the roll profile slope C is obtained from Equation VII:

[0062]

[0063] Thus, a working roll profile curve is uniquely determined,

[0064] Y(x) = -536.292sin[0.00013(x - 2050)]

[0065] +0.06808x - 1.57618×10 -7 x 2 +6.19066×10 -7 11x 3 -7.54959×10 -15 x 4

[0066] This roll profile curve is as Figure 2 shown.

[0067] Using the conventional variable crown work roll profile design method, the roll gap corresponding to the designed roll profile is compared with the roll gap obtained by the roll profile of the present invention. As shown in Fig. 4, Fig. 4(a) is the roll gap comparison at the roll shifting position of -150 mm, Fig. 4(b) is the roll gap comparison at the roll shifting position of 0 mm, and Fig. 4(c) is the roll gap comparison at the roll shifting position of 150 mm. It can be seen that there are obvious differences in the roll gap shapes.

[0068] During the actual rolling process, for a strip of a certain width, the edge wave of the strip can be controlled by positive roll shifting. As shown in Fig. 5, Fig. 5(a) is the roll gap within the 2500 mm strip width range of the conventional variable crown roll profile at the roll shifting of -150 mm, Fig. 5(b) is the roll gap within the 2500 mm strip width range of the roll profile of the present invention on the basis of the roll shifting of -150 mm with a positive roll shifting of 30 mm, that is, at the roll shifting of -120 mm, and Fig. 5(c) is the roll gap difference. It can be seen that when controlling the edge wave of the strip by positive roll shifting, compared with the conventional variable crown roll profile, the reduction of the central reduction can be achieved, thereby alleviating the middle wave, that is, realizing the synchronous adjustment of the reduction amounts at the edge and in the middle in the strip width direction, and achieving the beneficial effect of improving the edge-middle composite wave shape.

[0069] As shown in Fig. 6, Fig. 6(a) is the roll gap within the 3100 mm strip width range of the conventional variable crown roll profile at the roll shifting of -150 mm, Fig. 6(b) is the roll gap within the 3100 mm strip width range of the roll profile of the present invention on the basis of the roll shifting of -150 mm with a positive roll shifting of 30 mm, that is, at the roll shifting of -120 mm, and Fig. 6(c) is the roll gap difference. It can be seen that when controlling the edge wave of the strip by positive roll shifting, compared with the conventional variable crown roll profile, the reduction of the central reduction can be achieved, thereby alleviating the middle wave, that is, realizing the synchronous adjustment of the reduction amounts at the edge and in the middle in the strip width direction, and achieving the beneficial effect of improving the edge-middle composite wave shape.

[0070] As shown in Fig. 7, Fig. 7(a) is the roll gap within the 2500 mm strip width range of the conventional variable crown roll profile at the roll shifting of 100 mm, Fig. 7(b) is the roll gap within the 2500 mm strip width range of the roll profile of the present invention on the basis of the roll shifting of 100 mm with a positive roll shifting of 30 mm, that is, at the roll shifting of 130 mm, and Fig. 7(c) is the roll gap difference. It can be seen that when controlling the edge wave of the strip by positive roll shifting, compared with the conventional variable crown roll profile, the reduction of the central reduction can be achieved, thereby alleviating the middle wave, that is, realizing the synchronous adjustment of the reduction amounts at the edge and in the middle in the strip width direction, and achieving the beneficial effect of improving the edge-middle composite wave shape.

[0071] As shown in Fig. 8, Fig. 8(a) shows the roll gap within the strip width of 3100 mm when the roll shifting is 100 mm for the conventional variable crown roll profile. Fig. 8(b) shows the roll gap within the strip width of 3100 mm when the roll is shifted forward by 30 mm on the basis of a 100-mm roll shift, that is, when the roll shifting is 130 mm for the roll profile of the present invention. Fig. 8(c) shows the difference in roll gaps. It can be seen that when controlling the strip edge wave by forward roll shifting, compared with the conventional variable crown roll profile, the reduction of the central reduction can be achieved, thereby alleviating the center wave, that is, realizing the synchronous adjustment of the reduction amounts at the edge and in the middle in the strip width direction, achieving the beneficial effect of improving the edge-middle combined waviness.

Claims

1. A variable crown work roll profile with the ability to control edge-middle composite waves, characterized in that: The work roll profile curve adopts the function shown in Equation I: Where Y(x): the work roll profile function, unit: mm; x: the roll body coordinate, unit: mm, range: [0, L]; A: the profile amplitude, unit: mm; B: the profile offset, unit: mm; L: the roll body length, unit: mm; C: the profile slope, dimensionless; D: Composite wave control coefficient in the roll edge shape, unit: mm -1 ; E: Composite wave control coefficient in the roll edge, unit: mm -2 ; F: Composite wave control coefficient in the roll-shaped edge, unit: mm -3 ; According to the control requirements of the edge-middle composite wave, the fourth convexity C is given. h After that, the control coefficients D, E, and F of the roll profile edge-middle composite wave can be determined by Equations IV, V, and VI: where C h : the magnitude of the fourth convexity, which is negative, with the unit of mm; S m : The extreme shifting position of the work roll, in mm.

2. The variable crown work roll profile with edge-middle composite wave control ability as described in claim 1, wherein: Given the work roll body length L, the roll shifting stroke [-S m , S m , and the secondary crown control range [C w1 , C w2 , the roll profile parameters A and B can be determined by Equations II and III: Where C w1 : The secondary crown of the roll gap when the work roll is at the roll shifting position - S m , with the unit of mm; C w2 : The roll gap secondary convexity when the working roll is at the roll shifting position S m , with the unit of mm.

3. The variable crown work roll profile with edge-middle composite wave control ability according to claim 1, characterized in that: The profile slope C can be determined by Equation VII: W: the strip width, unit: mm.

4. The variable crown work roll profile with edge-middle composite wave control ability according to claim 1, characterized in that: For strips with different widths, the synchronous adjustment of the reduction amounts at the edges and in the middle in the strip width direction can be achieved by the forward roll shifting of the rolls, improving the edge and middle composite waviness.

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