A variable contact work roll profile design method for improving local high points of strip

Abstract

The application discloses a variable contact work roll shape design method capable of improving local high points of a strip, and belongs to the technical field of metallurgy and rolling. The method comprises the following steps: in the full length range of a roll, a full roll body area curve is designed based on strip crown; wherein the full roll body area curve is a quadratic parabola; an edge area curve is designed based on the width of a rolled strip and the position and size of local high points of the strip; wherein the edge area curve comprises a first parabola and a second parabola, and the first parabola and the second parabola are superimposed to form a chamfer, thereby playing a role of edge multiple pressing; and the full roll body area curve and the edge area curve are superimposed to obtain a work roll shape curve. Through the variable contact work roll shape technology, the local high points of the strip can be effectively improved, and the finished product strip shape quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metallurgy and rolling technology, and particularly relates to a variable contact work roll shape design method for improving local high points of a strip. BACKGROUND

[0002] In the process of hot strip rolling, due to the increase of strip speed in the strip threading process, the finishing temperature of the roll is increased, and the thermal expansion effect is intensified, which leads to roll deflection and less pressure at the edge of the strip when the rolling force is reduced. According to the law of minimum resistance, the strip will move towards the edge when the pressure of the roll at the edge of the strip is reduced, forming a local high point and presenting a cat ear shape. With the increase of the rolling number, the local high point will become more and more obvious. At this time, in order to ensure the quality of the product cross-section profile, the rolling unit production block number has to be shortened, and a new work roll has to be replaced to solve this problem, but this will temporarily interrupt the production and increase the number of roll changes, affecting the production line output. Therefore, the local high point is an important reason for restricting the rolling mileage and is a strip shape defect that needs to be focused on. SUMMARY

[0003] The present application provides a variable contact work roll shape design method for improving local high points of a strip, which solves the technical problem that in order to ensure the quality of the product cross-section profile, the rolling unit production block number has to be shortened, and a new work roll has to be replaced to solve this problem, but this will temporarily interrupt the production and increase the number of roll changes, affecting the production line output.

[0004] To solve the above technical problems, the present application provides the following technical solutions:

[0005] A variable contact work roll shape design method for improving local high points of a strip, comprising:

[0006] designing a full roll body area curve based on the strip crown in the full length range of the roll;

[0007] designing an edge area curve based on the width of the rolled strip and the position and size of the local high point of the strip; wherein the edge area curve comprises a first parabola and a second parabola, the first parabola and the second parabola are superimposed to form a chamfer, and the chamfer plays a role of more pressure at the edge;

[0008] superimposing the full roll body area curve and the edge area curve to obtain a work roll shape curve.

[0009] Further, the expression of the full roll body area curve is:

[0010]

[0011] Wherein, y1 is the longitudinal coordinate of the roll radius profile curve; x is the transverse coordinate of the roll with the midpoint of the roll as the origin; l is half of the roll body length; C1 is the coefficient of the full roll body area curve, which is related to the strip crown and is determined according to the required strip crown.

[0012] Further, the edge area curve is designed based on the width of the rolled strip and the position and size of the local high point of the strip, comprising:

[0013] designing a first parabola based on the width of the rolled strip and the position and size of the local high point of the strip;

[0014] designing a second parabola based on the coefficient of the first parabola and the position and size of the local high point of the strip.

[0015] Further, the expression of the first parabola is:

[0016]

[0017] Wherein, y2 is the longitudinal coordinate of the roll radius profile curve; x is the transverse coordinate of the roll with the midpoint of the roll as the origin; l is half of the roll body length; d is the corrected width of the strip; s is half of the difference between w and d, w is half of the width of the rolled strip; wherein, the corrected width of the strip d is related to the width of the rolled strip to ensure that the chamfer can be pressed to the edge of the strip, and its value is related to the width of the rolled strip; C2 is the coefficient of the first parabola, which is determined by the position and size of the local high point of the strip.

[0018] Further, the expression of the second parabola is:

[0019]

[0020] Wherein, y3 is the longitudinal coordinate of the roll radius profile curve; x is the transverse coordinate of the roll with the midpoint of the roll as the origin; l is half of the roll body length; w is half of the width of the rolled strip; C3 is the coefficient of the second parabola, which is determined by the position and size of the local high point of the strip and the coefficient of the first parabola.

[0021] Further, the expression of the working roll profile curve is:

[0022]

[0023] Wherein, y(x) is the longitudinal coordinate of the roll radius roll shape curve; x is the transverse coordinate of the roll taking the midpoint of the roll as the origin; l is half of the roll body length; w is half of the rolling strip width; d is the strip correction width; s is half of the difference between w and d; C1 is the coefficient of the full roll body area curve, which is determined according to the strip crown required by production; C2 is the coefficient of the first parabola, which is determined by the position and size of the local high point of the strip; C3 is the coefficient of the second parabola, which is determined by the position and size of the local high point of the strip and the coefficient of the first parabola.

[0024] The technical scheme provided by the present application has at least the following beneficial effects:

[0025] The present application designs a reasonable working roll shape curve according to the variable contact principle, i.e. changing the contact state between the roll and the strip as needed. The designed working roll shape controls the size of the edge over-pressing of the roll on the strip by adjusting parameters, so that the edge over-pressing of the roll is realized during rolling to compensate for the decrease of roll deflection and rolling force due to the thermal expansion of the strip caused by the increase of the strip speed during the strip threading process, so as to achieve the purpose of improving the local high point of the strip, a plate shape defect. After the roll shape is designed, it can be ground by a grinding machine in the form of high-order curve fitting. It can be seen that the present application is feasible and low in cost on the rolling mill. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 is the full roll body parabola diagram (working roll upper surface curve) provided by the embodiment of the present application;

[0028] Figure 2 is the original roll shape and variable contact roll shape diagram (working roll upper surface curve) provided by the embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0030] First, it should be noted that in the embodiments of the present application, the words "exemplary", "for example", and the like are used herein to mean serving as an example, instance, or illustration, and not necessarily as preferred or advantageous over other embodiments or designs. The use of these words in the description is not intended to convey that the embodiments described are the only way in which the application can be practiced. Rather, these words are used to provide examples of specific embodiments of the application. Additionally, the term "and / or" as used herein refers to both a conjunctive and disjunctive sense.

[0031] First embodiment

[0032] First, it should be noted that for the finishing mill group with parabolic roll shape, the variable contact roll shape can be used to reduce the occurrence of local high points, and the variable contact roll shape can be divided into three ways, which are edge more pressure, edge less pressure, and edge pressure reduction. After actual production verification, the roll shape using the first way can make the strip edge thickness thinning during rolling, which is beneficial to slow down the roll wear, and the local high point height is the smallest, which can effectively prolong the rolling cycle. In view of this, the variable contact work roll shape of edge more pressure can be used to improve the local high point problem of the strip, so that the strip edge thickness is thinned during rolling, thereby ensuring good cross-sectional shape, relieving "cat ear", and effectively prolonging the rolling mileage.

[0033] Based on the above, the present embodiment provides a variable contact work roll shape design method which can improve the local high point of the strip. The curve designed by the method contains two parts of full roll body area and edge area. The full roll body area adopts a quadratic parabola, and the edge area is designed to form a chamfer by superimposing two parabolas, which can play the role of edge more pressure. The coefficients of the parabola of the full roll body area are determined by the size of the parabola coefficients of the original roll shape, and the coefficients of the two parabolas of the edge area are determined according to the position and size of the local high point. Then, the segmented functions of the full roll body area and the edge area are superimposed to form a roll shape curve with special function in the width range of the strip.

[0034] Specifically, the execution process of the variable contact work roll shape design method includes the following steps:

[0035] S1, in the full length range of the roll, a full roll body area curve is designed based on the strip crown; wherein the full roll body area curve is a quadratic parabola;

[0036] It should be noted that the roll shape curve in the full roll body and roll body correction range of the present embodiment adopts a quadratic parabola. For this, in the full length range of the roll, the present embodiment designs the parabola according to the strip crown. If the strip crown is too large, the concavity of the parabola should be reduced to make the full roll body diameter smaller. If the strip crown is too small, the concavity of the parabola should be increased to make the full roll body diameter larger.

[0037] Specifically, the expression of the full roll body area curve is:

[0038]

[0039] wherein y1 is the longitudinal coordinate of the roll radius profile curve, in units of μm; x is the transverse coordinate of the roll with the roll midpoint as the origin, in units of mm; l is half of the roll body length, in units of mm; C1 is the coefficient of the full roll body area curve, which is related to the original roll profile crown and the strip crown, and is determined according to the required strip crown.

[0040] S2, designing an edge area curve based on the width of the rolled strip and the position and size of the local high point of the strip; wherein the edge area curve comprises a first parabola and a second parabola, the first parabola and the second parabola are superimposed to form a chamfer, and the chamfer plays a role of edge multi-pressing;

[0041] Specifically, in the embodiment, the implementation process of S2 comprises:

[0042] S21, designing a first parabola based on the width of the rolled strip and the position and size of the local high point of the strip;

[0043] wherein the expression of the first parabola is:

[0044]

[0045] wherein y2 is the longitudinal coordinate of the roll radius profile curve; x is the transverse coordinate of the roll with the roll midpoint as the origin; l is half of the roll body length; d is the corrected width of the strip; s is half of the difference between w and d, w is half of the width of the rolled strip; wherein the corrected width of the strip d is related to the width of the rolled strip, so as to ensure that the chamfer can press to the edge of the strip; C2 is the coefficient of the first parabola, which is determined by the position and size of the local high point of the strip.

[0046] S22, designing a second parabola based on the coefficient of the first parabola and the position and size of the local high point of the strip;

[0047] wherein the expression of the second parabola is:

[0048]

[0049] wherein y3 is the longitudinal coordinate of the roll radius profile curve; C3 is the coefficient of the second parabola, which is determined by the position and size of the local high point of the strip and the coefficient of the first parabola.

[0050] Based on the above, the full roll body parabolas are designed, as shown in Figure 1 .

[0051] S3, superimposing the full roll region curve and the edge region curve to obtain a roll shape curve of the work roll;

[0052] wherein the final work roll shape is superimposed by the segmented functions, and the calculation formula of the ordinate y(x) is:

[0053]

[0054] The comparison between the finally designed variable contact roll shape and the original roll shape is shown in the figure. Figure 2

[0055] In summary, the embodiment provides a variable contact work roll shape design method capable of improving local high points of a strip, and the work roll shape designed by the method is suitable for the case that the edge portion is under-pressed when the roll deflection and rolling force decrease due to the increase of the strip speed, the increase of the finishing temperature of the roll and the aggravation of the thermal expansion effect. The work roll shape can control the size of the over-pressing of the edge portion of the strip by adjusting the parameters, and the purpose of improving the local high point defects of the strip can be achieved. After the roll shape is designed, the roll shape can be ground by the high-order curve fitting method. It can be seen that the present application has high feasibility and low cost in the rolling mill. The roll shape can significantly improve the local high point problem of the strip after the experiment on the production line of a certain factory.

[0056] Second embodiment

[0057] The variable contact work roll shape design method capable of improving local high points of a strip provided by the present application is applied to the production line of a certain factory to verify the actual effect, and the implementation process is as follows:

[0058] The hot coil strip production line of a certain factory has no roll shifting function, the length of the work roll body is 1880mm, and the main rolling specification is a 1260mm wide strip. Since the roll shifting is not used, the edge portion of the roll is seriously worn, the local high point shape is more sharp, and the local high point is also concentrated in a very narrow range in the width direction.

[0059] According to the content of the present application, the corresponding variable contact work roll shape curve is designed. For the full roll parabola, the center of the roll is taken as the origin, a concave roll shape with a radius of 60μm is adopted, and the equation is as follows:

[0060]

[0061] Then, the chamfered parabola 1 part is calculated. In order to ensure that the roll shape can act on the local high point position, d is taken as 150mm and C2 is taken as 25, and the equation of the chamfered parabola 1 is as follows:

[0062]

[0063] ​Then the curve of chamfer parabola 2 is designed by the curve of chamfer parabola 1, in order to ensure the applicability of the roll, the superimposed chamfer should not be too high, therefore, C3 is taken as -240 to press the chamfer parabola 1.

[0064] The equation of the chamfer parabola is as follows:

[0065]

[0066] The parabolas of the whole roll body are as shown in the figure (only the working roll upper surface curve is shown). Figure 1

[0067] The whole parabolas are superimposed, and the roll shape of the whole roll body is expressed in segments, and the final formula is as follows:

[0068]

[0069] The comparison between the finally designed variable contact roll shape and the original roll shape is as shown in the figure (working roll upper surface curve). Figure 2

[0070] The high-order fitting curve data of the roll shape curve is submitted to the grinding machine, and after the on-machine grinding, it is applied to the production site, effectively solving the local high point problem existing in the production of the production line, and good application effect is obtained.

[0071] In addition, it should be noted that in this paper, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between the entities or operations. The terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or terminal device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or terminal device. Without more limitation, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or terminal device including the element.

[0072] Finally, it should be noted that the above description is only the preferred embodiment of the present application, and it should be pointed out that although the preferred embodiments of the present application have been described, for those skilled in the art, once the basic creative concept of the present application is known, without departing from the principles of the present application, several improvements and refinements can also be made, which should also be considered as the protection scope of the present application. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.​​

Claims

1. A method for designing the profile of a variable contact work roll capable of improving the local high point of a plate strip, characterized in that: include: Within the full length of the roll, a full roll area curve is designed based on the strip crown; wherein the full roll area curve is a quadratic parabola; The edge area curve is designed based on the width of the rolled strip and the location and size of the local high point of the strip; wherein the edge area curve includes a first parabola and a second parabola, and the first parabola and the second parabola are superimposed to form a chamfer, and the chamfer plays the role of multi-pressure of the edge; The full roll area curve and the edge area curve are superimposed to obtain a work roll shape curve; The edge area curve is designed based on the width of the rolled strip and the position and size of the local high point of the strip, including: The first parabola is designed based on the width of the rolled strip and the position and size of the local high point of the strip; Design the second parabola based on the coefficient of the first parabola and the position and size of the local high point of the plate strip; The expression of the first parabola is: Where y2 is the longitudinal coordinate of the roll radius and roll profile curve; x is the transverse coordinate of the roll with the roll midpoint as the origin; l is half the roll body length; d is the corrected strip width; s is half the difference between w and d, where w is half the width of the rolled strip. The corrected strip width d is used to ensure that the chamfer can be pressed to the edge of the strip, so its value is related to the width of the rolled strip; C2 is the coefficient of the first parabola, and its value is determined by the location and size of the local high point of the strip. The expression of the second parabola is: Among them, y3 is the longitudinal coordinate of the roller radius and roller shape curve; x is the transverse coordinate of the roller with the midpoint of the roller as the origin; l is half of the roller body length; w is half of the rolled strip width; C3 is the coefficient of the second parabola, and its value is determined by the position and size of the local high point of the strip and the coefficient of the first parabola.

2. The method for designing a variable contact work roll profile capable of improving local high points of a strip as claimed in claim 1, characterized in that: The expression of the full roller area curve is: Among them, y1 is the longitudinal coordinate of the roller radius roll curve; x is the transverse coordinate of the roller with the midpoint of the roller as the origin; l is half the length of the roller body; C1 is the coefficient of the full roller body area curve, its value is related to the crown of the plate and strip, and is determined according to the crown of the plate and strip required for production.

3. The method for designing a variable contact work roll profile capable of improving local high points of a strip as claimed in claim 1, characterized in that: The expression of the working roll shape curve is: Among them, y(x) is the longitudinal coordinate of the roller radius roller curve; x is the transverse coordinate of the roller with the midpoint of the roller as the origin; l is half of the roller body length; w is half of the rolled strip width; d is the corrected strip width; s is half of the difference between w and d; C1 is the coefficient of the full roller body area curve, its value is related to the strip convexity, and is determined according to the strip convexity required for production; C2 is the coefficient of the first parabola, its value is determined by the position and size of the local high point of the strip; C3 is the coefficient of the second parabola, its value is determined by the position and size of the local high point of the strip and the coefficient of the first parabola.

Images