Variable contact working roll shape design method capable of improving local high points of plate strip

Abstract

The invention discloses a variable contact working roll shape design method capable of improving local high points of a plate strip, and belongs to the technical field of metallurgy and rolling. The method comprises the steps that a whole roll body area curve is designed based on the convexity of the plate strip within the full-length range of a roll; wherein the whole roller body area curve is a section of quadratic parabola; an edge area curve is designed based on the width of the rolled plate strip and the position and size of local high points of the plate strip; wherein the edge region curve comprises a first parabola and a second parabola, the first parabola and the second parabola are overlapped to form a chamfer, and the effect of excessive pressure on the edge is achieved; and superposing the whole roll body area curve and the edge area curve to obtain a roll shape curve of the working roll. By means of the variable contact working roller shape technology, the local high points of the plate strip can be effectively improved, and the plate shape quality of a finished product is improved.

Description

Technical Field

[0001] The invention relates to the field of metallurgy and rolling technology, and in particular to a method for designing the roll shape of a variable contact working roll capable of improving the local high points of a plate strip. Background Art

[0002] During the hot rolling of plates and strips, the strip speed increases during the strip threading process, the final rolling temperature of the rollers increases, and the thermal expansion effect intensifies, resulting in roll deflection and less pressure on the edges when the rolling force decreases. When the pressure of the rollers on the edges of the strips decreases, the strips will move toward the edges due to the "law of least resistance", forming local high points, showing a "cat ear shape", and as the number of rolled coils increases, the local high points will become more and more significant. At this time, in order to ensure the quality of the product cross-sectional profile, the number of production blocks of the rolling unit has to be shortened, and this problem is solved by replacing new working rolls, but this will temporarily interrupt production, increase the number of roll changes, and affect the output of the production line. It can be seen that local high points are an important reason for restricting the number of rolling kilometers and are plate shape defects that need to be addressed. Summary of the invention

[0003] The present invention provides a variable contact working roll shape design method that can improve the local high points of the plate and strip, so as to solve the local high point defects of the plate and strip that occur during the rolling process. In order to ensure the quality of the product cross-sectional profile, the prior art has to shorten the number of production blocks of the rolling unit and solve this problem by replacing new working rolls, but this will temporarily interrupt production, increase the number of roll changes, and affect the production line output. Technical problems.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A variable contact work roll profile design method for improving local high points of a plate strip comprises:

[0006] Within the full length of the roll, a full roll area curve is designed based on the convexity of the strip; wherein the full roll area curve is a quadratic parabola;

[0007] 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; wherein the edge area curve includes a first parabola and a second parabola, 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;

[0008] The full roll body area curve and the edge area curve are superimposed to obtain a working roll shape curve.

[0009] Furthermore, the expression of the full roller area curve is:

[0010]

[0011] 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 curve of the entire roller body area, and its value is related to the convexity of the plate and strip and is determined according to the convexity of the plate and strip required for production.

[0012] Furthermore, 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:

[0013] Designing the first parabola based on the width of the rolled strip and the location and size of the local high point of the strip;

[0014] The second parabola is designed based on the coefficients of the first parabola and the location and size of the local high point of the plate strip.

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

[0016]

[0017] Among them, y2 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; d is the corrected width of the strip; s is half of the difference between w and d, and w is half of the width of the rolled strip; among them, the corrected width d of the strip is 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 position and size of the local high point of the strip.

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

[0019]

[0020] Among them, y3 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 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.

[0021] Furthermore, the expression of the working roll shape curve is:

[0022]

[0023] Among them, y(x) 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 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 curve of the entire roller body area, and its value is related to the convexity of the strip and is determined according to the convexity of the strip required for production; C2 is the coefficient of the first parabola, and 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, 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.

[0024] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0025] The present invention is based on the variable contact principle, that is, changing the contact state between the roller and the strip as needed, and designs a reasonable working roller roll curve. The designed working roller roll shape controls the size of the roller's multi-pressure on the edge of the strip by adjusting parameters, so that the roller can achieve multi-pressure on the edge during the rolling process to compensate for the thermal expansion caused by the increase in the strip speed during the strip threading process, resulting in reduced roll deflection and reduced rolling force, so as to achieve the purpose of improving the plate shape defect of the local high point of the strip. After the roller shape design is completed, it can be ground by a grinder in a high-order curve fitting manner. It can be seen that the scheme of the present invention is highly feasible and low-cost to implement on a rolling mill. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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.

[0027] Figure 1 Schematic diagram of various parabolas of the full roll body (working roll upper surface curve) provided in an embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of the original roll shape and the variable contact roll shape (working roll upper surface curve) provided in an embodiment of the present invention. DETAILED DESCRIPTION

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

[0030] First of all, it should be noted that in the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "exemplarily" is intended to present the concept in a concrete way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0031] First embodiment

[0032] First of all, it should be noted that for the finishing mill with parabolic roll shape, variable contact roll shape can be used to reduce the generation of local high points, and variable contact roll shape can be divided into three modes, namely, more edge pressure, less edge pressure, and slow edge pressure. After actual production verification, the first type of roll shape can reduce the thickness of the strip edge during the rolling process, which is beneficial to slow down the wear of the roll, and the height of the local high point is minimized, which can effectively extend the rolling cycle. In view of this, the variable contact working roll shape with more edge pressure can be used to improve the local high point problem of the plate and strip, so that the thickness of the plate and strip edge is thinned during the rolling process, thereby ensuring a good cross-sectional shape, alleviating "cat ears", and effectively extending the rolling mileage.

[0033] Based on the above, this embodiment provides a variable contact working roll roll shape design method that can improve the local high point of the plate strip. The curve designed by this method includes two parts: the full roller body area and the edge area. Among them, the full roller body area adopts a quadratic parabola, and the edge area is designed to superimpose two parabolas to form a chamfer, which can play the role of multi-pressure on the edge. The coefficient of the parabola in the full roller body area is determined by the size of the parabola coefficient of the original roller shape, and the coefficients of the two parabolas at the edge are determined according to the position and size of the local high point. Then, the piecewise functions of the full roller body area and the edge area are superimposed to form a roller curve with special functions within the width range of the plate strip.

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

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

[0036] Among them, it should be noted that the roller shape curve of this embodiment within the entire roller body and the roller body correction range adopts a quadratic parabola. In this regard, this embodiment designs the parabola according to the convexity of the plate and strip within the entire length of the roller. If the convexity of the plate and strip is too large, the concavity of the parabola should be reduced to reduce the roller diameter of the entire roller body; if the convexity of the plate and strip is too small, the concavity of the parabola should be increased to increase the roller diameter of the entire roller body.

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

[0038]

[0039] Among them, y1 is the longitudinal coordinate of the roller radius roll curve, unit μm; x is the transverse coordinate of the roller with the midpoint of the roller as the origin, unit mm; l is half of the roller body length, unit mm; C1 is the coefficient of the full roller body area curve, its value is related to the original roller shape convexity and the strip convexity, and is determined according to the strip convexity required for production.

[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 includes 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 multi-pressure of the edge;

[0041] Specifically, in this embodiment, the implementation process of the above S2 includes:

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

[0043] Wherein, the expression of the first parabola is:

[0044]

[0045] Among them, y2 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; d is the corrected width of the strip; s is half of the difference between w and d, and w is half of the width of the rolled strip; among them, the corrected width d of the strip is 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 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 plate strip;

[0047] Wherein, the expression of the second parabola is:

[0048]

[0049] Among them, y3 is the longitudinal coordinate of the roller radius and roller shape curve; 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 plate and strip and the coefficient of the first parabola.

[0050] Based on the above, the parabolas of the whole roller body are designed. Figure 1 shown.

[0051] S3, superimposing the full roller body area curve and the edge area curve to obtain the working roll shape curve;

[0052] Among them, the final working roll shape will be formed by superposition of piecewise functions, and the calculation formula of its ordinate y(x) is:

[0053]

[0054] The final design of the variable contact roller shape and the original roller shape are compared. Figure 2 shown.

[0055] In summary, this embodiment provides a variable contact working roll shape design method that can improve the local high points of the plate and strip. The working roll shape designed by the above method is suitable for the situation where the edge is under-pressed when the roll bends and the rolling force decreases due to the increase in strip speed, the increase in the final rolling temperature of the roll, and the intensification of the thermal expansion effect during the strip threading process. The working roll shape can achieve the purpose of improving the local high point defects of the plate and strip by adjusting parameters to control the amount of pressure exerted by the roll on the edge of the plate and strip. After the roll shape design is completed, it can be ground by a grinder in a high-order curve fitting method. It can be seen that the scheme of the present invention is highly feasible and low-cost to implement on a rolling mill. After the on-machine experiment on a certain factory production line, it was shown that this type of roll shape can significantly improve the problem of local high points of the plate and strip.

[0056] Second embodiment

[0057] In this embodiment, the variable contact work roll profile design method provided by the present invention that can improve the local high point of the plate strip is applied to a production line of a certain factory to verify its actual effect. The implementation process is as follows:

[0058] A hot rolled plate production line in a certain factory has a single stand without roll shifting function, a working roll body length of 1880mm, and a main rolling specification of 1260mm wide plate and strip. Due to the lack of roll shifting, the roll edge is severely worn, the local high point shape is sharper, and it is also concentrated in a very narrow range in the width direction.

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

[0060]

[0061] Then calculate the chamfer parabola 1. To ensure that the roll shape can act on the local high point, take d as 150mm and C2 as 25, and the equation of chamfer parabola 1 is as follows:

[0062]

[0063] Then, chamfer parabola 2 is designed based on the curve of chamfer parabola 1. In order to ensure the applicability of the rolling mill, the chamfer formed by superposition should not be too high. Therefore, C3 is set to -240 to press chamfer parabola 1 down.

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

[0065]

[0066] The parabolas of the entire roller body are as follows Figure 1 As shown (only the upper surface curve of the working roll is shown).

[0067] All parabolas are superimposed and the roll shape of the entire roller body is expressed in sections. The final formula is as follows:

[0068]

[0069] The final design of the variable contact roller shape and the original roller shape are compared. Figure 2 Shown (working roll upper surface curve).

[0070] The higher-order fitting curve data of the roller curve was submitted to the grinder, and applied to the production site after being ground on the machine. This effectively solved the problem of local high points in the production line when producing plates and strips, and achieved good application results.

[0071] In addition, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprises a..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0072] Finally, it should be noted that the above is only a preferred embodiment of the present invention. It should be pointed out that although the preferred embodiment of the present invention has been described, for ordinary technicians in this technical field, once the basic creative concept of the present invention is known, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. Therefore, the attached claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the embodiments of the present invention.

Claims

1. A method for designing the roll shape 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 convexity of the strip; 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 position and size of the local high point of the strip; wherein the edge area curve includes a first parabola and a second parabola, 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 body area curve and the edge area curve are superimposed to obtain a working roll shape curve.

2. The variable contact work roll profile design method for improving the local high point of the plate strip according to 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 curve of the entire roller body area, and its value is related to the convexity of the plate and strip and is determined according to the convexity of the plate and strip required for production.

3. The variable contact work roll profile design method for improving the local high point of the plate strip according to claim 1, characterized in that: The design of the edge area curve based on the width of the rolled strip and the position and size of the local high point of the strip includes: Designing the first parabola based on the width of the rolled strip and the location and size of the local high point of the strip; The second parabola is designed based on the coefficients of the first parabola and the location and size of the local high point of the plate strip.

4. The variable contact work roll profile design method for improving the local high point of the plate strip as claimed in claim 3, characterized in that: The expression of the first parabola is: Among them, y2 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; d is the corrected width of the strip; s is half of the difference between w and d, and w is half of the width of the rolled strip; among them, the corrected width d of the strip is 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 position and size of the local high point of the strip.

5. The method for designing the roll shape of a variable contact work roll capable of improving the local high point of a plate strip as claimed in claim 3, characterized in that: The expression of the second parabola is: Among them, y3 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 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.

6. The variable contact work roll profile design method for improving the local high point of the plate strip according to 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 roll 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 curve of the entire roller body area, and its value is related to the convexity of the strip and is determined according to the convexity of the strip required for production; C2 is the coefficient of the first parabola, and 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, 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.

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