A pre-slit hole type correction method

Abstract

The application discloses a pre-cutting hole type correction method and relates to the technical field of steel rolling. The total elongation rate of a rolled piece passing through a rolling hole is obtained; the nominal cross-sectional area of a product is obtained; the difference between the actual weight negative deviation of the product and the target weight negative deviation is calculated; the area reduction value of the pre-cutting hole is calculated according to the total elongation rate, the nominal cross-sectional area, the difference and the cutting number of the pre-cutting hole; and the hole type parameters of the pre-cutting hole are corrected according to the area reduction value. Compared with the prior art, the pre-cutting hole type correction method can guarantee that the weight of the product is stably within the negative deviation range, reduces the material cost and improves the production benefit.

Description

Technical Field

[0001] This invention relates to the field of steel rolling technology, and more specifically, to a method for correcting pre-cutting die profiles. Background Technology

[0002] Currently, in the steel rolling process, the workpiece needs to undergo multiple rolling passes to obtain a product of a predetermined size and shape. In this multi-pass rolling process, the workpiece is first pre-cut, then divided into multiple parts, and each part is then rolled to form the final product. However, the product weight needs to meet the national standard's allowable positive and negative deviations. The weight of the product obtained through the above rolling method may fall within the positive or negative deviation range. This means the product weight cannot be consistently kept within the negative deviation range, leading to increased material costs and impacting production efficiency.

[0003] In view of this, designing a pre-cutting die correction method to ensure stable negative deviation in product weight is particularly important in steel rolling production. Summary of the Invention

[0004] The purpose of this invention is to provide a pre-cutting hole correction method that can ensure the weight of the product remains within the negative deviation range, reduce material costs, and improve production efficiency.

[0005] The present invention is achieved by the following technical solution.

[0006] A method for correcting pre-cutting hole profile includes: obtaining the total elongation of the rolled piece through the rolling hole; obtaining the nominal cross-sectional area of ​​the product; calculating the difference between the actual negative weight deviation and the target negative weight deviation of the product; calculating the area reduction value of the pre-cutting hole based on the total elongation, nominal cross-sectional area, difference, and number of pre-cutting holes; and correcting the hole profile parameters of the pre-cutting hole based on the area reduction value.

[0007] Optionally, before obtaining the total elongation of the workpiece through the rolling hole, the pre-cutting hole correction method further includes: calculating the fluctuation difference between the negative weight deviation at the head and the negative weight deviation at the tail of the product; if the fluctuation difference is greater than 0.6%, then reducing the tension between the rolling mills.

[0008] Optionally, the rolling hole includes a slitting hole and a forming hole. The step of obtaining the total elongation of the rolled piece through the rolling hole includes: obtaining a first elongation of the rolled piece through the slitting hole; obtaining a second elongation of the rolled piece through the forming hole; and multiplying the first elongation and the second elongation to obtain the total elongation.

[0009] Optionally, the step of obtaining the first elongation of the rolled piece through the slitting hole includes: measuring the first cross-sectional area of ​​the rolled piece before passing through the slitting hole; measuring the second cross-sectional area of ​​the rolled piece after passing through the slitting hole; and dividing the first cross-sectional area by the second cross-sectional area to obtain the first elongation.

[0010] Optionally, the step of obtaining the first elongation of the rolled piece through the slitting hole includes: measuring the first length of the rolled piece before passing through the slitting hole; measuring the second length of the rolled piece after passing through the slitting hole; and dividing the second length by the first length to obtain the first elongation.

[0011] Optionally, the number of forming holes is multiple, and the step of obtaining the second elongation of the rolled piece through the forming holes includes: obtaining the partial elongation of the rolled piece through each forming hole; multiplying the multiple partial elongation rates to obtain the second elongation rate.

[0012] Optionally, the step of calculating the area reduction value of the pre-cut holes based on the total elongation, nominal cross-sectional area, difference, and number of pre-cut holes includes: calculating the area reduction value using the calculation formula: S1=S2×λ×a×n; where S1 is the area reduction value, S2 is the nominal cross-sectional area, λ is the total elongation, a is the difference, and n is the number of cuts.

[0013] Optionally, in the step of calculating the area reduction value of the pre-cut holes based on the total elongation, nominal cross-sectional area, difference, and number of pre-cut holes, the number of cuts is three.

[0014] Optionally, the hole parameters include the parallel circle spacing, the groove bottom curvature, and the hole sidewall inclination angle. The steps of correcting the hole parameters of the pre-cut hole according to the area reduction value include: reducing the parallel circle spacing; reducing the groove bottom curvature; and reducing the hole sidewall inclination angle.

[0015] Optionally, the hole parameters also include hole height and groove radius. The step of correcting the hole parameters of the pre-cut hole according to the area reduction value also includes: reducing the hole height; increasing the groove radius.

[0016] The pre-cutting hole type correction method provided by the present invention has the following beneficial effects:

[0017] The pre-splitting hole correction method provided by this invention obtains the total elongation of the rolled piece passing through the rolling hole; obtains the nominal cross-sectional area of ​​the product; calculates the difference between the actual negative weight deviation and the target negative weight deviation of the product; calculates the area reduction of the pre-splitting hole based on the total elongation, nominal cross-sectional area, difference, and the number of pre-splitting holes; and corrects the hole shape parameters of the pre-splitting hole based on the area reduction value. Compared with the prior art, the pre-splitting hole correction method provided by this invention, by adopting the step of correcting the hole shape parameters of the pre-splitting hole based on the area reduction value, can ensure that the weight of the product is stably within the negative deviation range, reduce material costs, and improve production efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating the steps of the pre-cutting hole type correction method provided in an embodiment of the present invention;

[0020] Figure 2 A mathematical model diagram of the pre-splitting hole used in the pre-splitting hole type correction method provided in the embodiments of the present invention;

[0021] Figure 3 A mathematical model diagram of the pre-cutting hole correction method provided in this embodiment of the invention applied to the cutting hole in the steel rolling production process;

[0022] Figure 4 A mathematical model diagram of the pre-cutting hole correction method provided in this embodiment of the invention applied to the first forming hole in the steel rolling production process;

[0023] Figure 5 A mathematical model diagram of the pre-cutting hole correction method provided in this embodiment of the invention applied to the second forming hole in the steel rolling production process;

[0024] Figure 6 A mathematical model diagram of the pre-cutting hole correction method provided in this embodiment of the invention applied to the third forming hole in the steel rolling production process;

[0025] Figure 7 The mathematical model diagram of the pre-cutting hole correction method provided in the embodiment of the present invention applied to the fourth forming hole in the steel rolling production process. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] In the description of this invention, it should be noted that the terms "inner," "outer," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," "installed," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, features in the following embodiments can be combined with each other.

[0032] Please refer to the reference. Figures 1 to 7 This invention provides a method for correcting the shape of pre-cut holes, which can ensure that the weight of the product remains within a negative deviation range, reduce material costs, and improve production efficiency.

[0033] It should be noted that the pre-cutting pass correction method is applied to steel rolling production. In the steel rolling process, the workpiece is first rolled using a pre-cutting pass on the first roll to pre-cut it into multiple segments of the same size and shape, connected sequentially. Next, a cutting pass on the second roll is used to further cut these segments. Then, a forming pass on the third roll is used to roll each segment into a predetermined shape and size, resulting in the final product. The cutting pass and forming pass are collectively referred to as rolling passes. The pre-cutting pass correction method can correct the shape of the original pre-cutting passes to ensure that the weight of the final product remains consistently within a negative deviation range, thus reducing material costs.

[0034] Specifically, to ensure the product's weight remains consistently within a negative deviation range, the pre-cutting hole, slitting hole, or forming hole needs to be modified to reduce the hole area, thereby reducing the cross-sectional area of ​​the rolled piece passing through the hole and ultimately reducing the product's weight, thus ensuring a stable negative deviation in product weight. Specifically, since the elongation of the rolled piece has a limit, the area of ​​the forming hole cannot be reduced to ensure the formed product meets the preset shape and dimensions. Furthermore, since the elongation of the rolled piece passing through the slitting hole is very small, and the slitting hole only cuts the rolled piece, its area cannot be reduced. However, the pre-cutting hole plays a crucial role in shaping the material, and the elongation of the rolled piece passing through it is relatively large. Therefore, modifying the pre-cutting hole is the most effective way to ensure a stable negative deviation in product weight by reducing its area.

[0035] It is worth noting that the pre-cutting hole type correction method includes the following steps:

[0036] Step S110: Calculate the fluctuation difference between the negative weight deviation at the head and tail of the product. If the fluctuation difference is greater than 0.6%, reduce the tension between the rolling mills.

[0037] It should be noted that in step S110, the product produced by the original rolling mill is first measured to obtain the negative weight deviation at the head and tail of the product. Then, the negative weight deviation at the head and tail are subtracted and the absolute value is taken to obtain the fluctuation difference. Next, the fluctuation difference is judged. If the fluctuation difference is less than or equal to 0.6%, it means that the tension between the rolling mills is in a state of micro-tension, the weight fluctuation of the product strip is small, which meets the theoretical calculation requirements, and the pre-cutting pass correction method can be used for correction. If the fluctuation difference is greater than 0.6%, it means that the tension between the rolling mills is too large, and there is a forced extension, which affects the subsequent calculation. At this time, it is necessary to reduce the tension between the rolling mills until the fluctuation difference of the produced product is less than or equal to 0.6% before proceeding to the next step.

[0038] Step S120: Obtain the total elongation of the workpiece through the rolling hole.

[0039] In this embodiment, the rolling hole includes a slitting hole (such as...). Figure 3 (as shown in the figure) and forming holes, wherein the cutting holes are used to cut the rolled piece into multiple segments of rolled piece with the same size and shape, and the forming holes are used to roll each segment of rolled piece into a preset shape and size.

[0040] Specifically, step S120 includes three steps, namely:

[0041] Step S121: Obtain the first elongation of the rolled piece through the slitting hole.

[0042] It should be noted that in step S121, the first cross-sectional area of ​​the rolled piece before passing through the slitting hole and the second cross-sectional area of ​​the rolled piece after passing through the slitting hole are first measured; then the first cross-sectional area is divided by the second cross-sectional area to obtain the first elongation. Specifically, since the slitting hole divides the rolled piece into multiple segments, the second cross-sectional area after rolling is equal to the sum of the cross-sectional areas of the multiple segments of the rolled piece.

[0043] In this embodiment, according to the principle of constant volume, it can be known that the volume of the workpiece before rolling is equal to the volume after rolling. That is, the product of the first cross-sectional area and the first length of the workpiece before rolling is equal to the product of the second cross-sectional area and the second length of the workpiece after rolling. Therefore, the ratio of the first cross-sectional area to the second cross-sectional area is the first elongation, and the ratio of the second length to the first length is also the first elongation.

[0044] In other embodiments, the first length of the rolled piece before passing through the slitting hole and the second length of the rolled piece after passing through the slitting hole can be measured first, and then the second length can be divided by the first length to obtain the first elongation. The method of obtaining the first elongation is not specifically limited.

[0045] Step S122: Obtain the second elongation of the rolled piece through the forming hole.

[0046] It is worth noting that there are multiple forming holes. The rolled part passes through multiple forming holes in sequence, and the shape and size of each forming hole gradually change so that the final rolled product meets the preset shape and size.

[0047] Specifically, step S122 includes two steps, namely:

[0048] Step S1221: Obtain the partial elongation of the rolled piece through each forming hole.

[0049] It should be noted that in step S1221, the cross-sectional area of ​​the rolled piece before passing through the forming hole and the cross-sectional area of ​​the rolled piece after passing through the forming hole are first measured; then the cross-sectional area before passing through the forming hole is divided by the cross-sectional area after passing through the forming hole to obtain the partial elongation; this process is repeated to calculate the partial elongation of the rolled piece through each forming hole.

[0050] Step S1222: Multiply the multiple elongation rates together to obtain the second elongation rate.

[0051] It should be noted that in step S1222, multiple partial elongations are multiplied together to obtain the second elongation of the rolled piece as it passes through multiple forming holes in sequence.

[0052] In this embodiment, there are four forming holes, and four different elongation rates. The rolled piece passes through four forming holes sequentially, with the shape and size of each hole gradually changing to ensure the final rolled product meets the preset shape and size. Specifically, the rolled piece passes through the first forming hole (e.g., ... Figure 4 (as shown in the shape), the second forming hole (as shown in the shape) Figure 5 (as shown in the shape), the third forming hole (as shown in the shape) Figure 6 (as shown in the shape) and the fourth forming hole (as shown in the shape) Figure 7 As shown in the figure, the four forming holes roll the product step by step into the preset shape and size.

[0053] Step S123: Multiply the first elongation and the second elongation to obtain the total elongation.

[0054] It should be noted that in step S123, the first elongation and the second elongation are multiplied to obtain the total elongation of the rolled piece as it passes through the slitting hole and multiple forming holes in sequence.

[0055] Step S130: Obtain the nominal cross-sectional area of ​​the product.

[0056] It should be noted that in step S130, the nominal cross-sectional area of ​​the product according to national standard specifications is obtained by looking up a table.

[0057] Step S140: Calculate the difference between the negative deviation of the actual product weight and the negative deviation of the target weight.

[0058] It should be noted that in step S140, the average value of the negative deviation of the product head weight and the negative deviation of the product tail weight obtained in step S110 is first taken to obtain the actual negative deviation of the product weight; then, the target negative deviation is set according to the lower limit of the negative deviation of the product national standard and the error fluctuation of the existing equipment and process; then, the actual negative deviation of the product weight and the target negative deviation are subtracted to obtain the difference.

[0059] Step S150: Calculate the reduction in area of ​​the pre-cut holes based on the total elongation, nominal cross-sectional area, difference, and number of pre-cut holes.

[0060] It should be noted that in step S150, the area reduction value is calculated using the following formula: S1=S2×λ×a×n; where S1 is the area reduction value, S2 is the nominal cross-sectional area, λ is the total elongation, a is the difference, and n is the number of segments.

[0061] In this embodiment, the number of cuts is three: the pre-cutting hole can pre-cut the rolled piece into three rolled pieces of the same size and shape that are connected in sequence; the cutting hole can cut the three rolled pieces of the same size and shape apart; and the forming hole can roll each rolled piece into a product of a preset shape and size.

[0062] Step S160: Correct the hole shape parameters of the pre-cut holes according to the area reduction value.

[0063] It is worth noting that the hole profile parameters include the parallel circle spacing, groove bottom curvature, hole sidewall inclination angle, hole height, and groove opening radius. Adjusting these parameters can reduce the area of ​​the pre-cut holes without affecting normal production, thereby ensuring the product weight remains within the negative deviation range, reducing material costs, and improving production efficiency. For ease of understanding, let the parallel circle spacing be represented as A, the groove bottom curvature as B, the hole sidewall inclination angle as C, the hole height as D, and the groove opening radius as E.

[0064] It should be noted that in step S160, the hole parameters such as the parallel circle spacing, groove bottom curvature, hole sidewall inclination angle, hole height, and groove fillet are modified according to the area reduction value in order to reduce the area of ​​the original pre-cut hole and obtain a new pre-cut hole. The difference between the area of ​​the original pre-cut hole and the area of ​​the new pre-cut hole is the area reduction value.

[0065] Specifically, the methods for correcting the hole profile parameters include: reducing the parallel circle spacing; reducing the groove bottom curvature; reducing the hole profile sidewall inclination angle; reducing the hole profile height; and increasing the groove opening radius. These five correction methods have a specific order: in the process of correcting the hole profile parameters, the parallel circle spacing is reduced first to decrease the area of ​​the original pre-cut hole. If reducing the parallel circle spacing alone cannot precisely meet the area reduction requirement, or if the process does not meet the requirements, then the groove bottom curvature is reduced. If both reducing the parallel circle spacing and reducing the groove bottom curvature simultaneously cannot precisely meet the area reduction requirement, or if the process does not meet the requirements, then the hole profile sidewall inclination angle is reduced. Similarly, it is determined whether the hole profile height and groove opening radius need to be adjusted to ensure that the area of ​​the original pre-cut hole is reduced to obtain the area of ​​the new pre-cut hole, thereby ensuring that the product weight remains within the negative deviation range.

[0066] In this embodiment, taking the production of 16 mm diameter rebar as an example, pre-cutting hole correction is performed. First, the negative deviation of the head weight of the rebar produced by the original mill is measured to be -2.9%, and the negative deviation of the tail weight is -2.5%. The calculated fluctuation difference is 0.4% < 0.6%, meeting the theoretical calculation requirements. Then, the first elongation λ1 = 1.180 of the rolled piece passing through the cutting hole is obtained, and the second elongation λ2 = λ... is obtained as the rolled piece passes through the four forming holes sequentially. 分1 ×λ 分2 ×λ 分3 ×λ 分4 =1.231×1.318×1.132×1.196=2.197, and the total elongation λ=λ1×λ2=2.592 is calculated; then, by referring to the table, the nominal cross-sectional area of ​​the national standard 16 mm diameter rebar is obtained as 201.1 square millimeters; then, the average of the negative weight deviations of the head and tail of the rebar produced by the original rolling mill is taken as -2.7%, and the target negative weight deviation is set as -3.5%, and the difference is calculated to be 0.8%; finally, the area reduction value of the pre-cutting hole S1=S2×λ×a×n=201.1 is calculated. ×2.592×0.8%×3=12.5 square millimeters; Finally, based on the reduction in area, the hole parameters are corrected. The parallel circle spacing is adjusted from the original 27.8 mm to the current 27.6 mm, the groove bottom curvature is adjusted from 13.4 mm to 13.2 mm, and the hole sidewall inclination angle is adjusted from 127 degrees to 125 degrees. As a result, the hole area of ​​the pre-cut hole is reduced from the original 1621.02 square millimeters to 1608.52 square millimeters, so as to ensure that the negative deviation of the produced rebar is stable within the range of -3.5%±0.2%, thereby reducing material costs and improving production efficiency.

[0067] The pre-splitting hole correction method provided in this invention obtains the total elongation of the rolled piece passing through the rolling hole; obtains the nominal cross-sectional area of ​​the product; calculates the difference between the actual negative weight deviation and the target negative weight deviation of the product; calculates the area reduction of the pre-splitting hole based on the total elongation, nominal cross-sectional area, difference, and the number of pre-splitting holes; and corrects the hole shape parameters of the pre-splitting hole based on the area reduction value. Compared with the prior art, the pre-splitting hole correction method provided in this invention, by employing the step of correcting the hole shape parameters of the pre-splitting hole based on the area reduction value, can ensure that the product weight is stably within the negative deviation range, reduce material costs, and improve production efficiency.

[0068] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for pre-cutting and correcting hole patterns, characterized in that, include: Obtain the total elongation of the workpiece through the rolling hole; Obtain the nominal cross-sectional area of ​​the product; The difference between the negative deviation of the actual weight of the product and the negative deviation of the target weight is calculated. The area reduction of the pre-splitting hole is calculated based on the total elongation, the nominal cross-sectional area, the difference, and the number of pre-splitting holes. The hole shape parameters of the pre-cut holes are corrected based on the area reduction value.

2. The pre-cutting hole type correction method according to claim 1, characterized in that, Before the step of obtaining the total elongation of the workpiece through the rolling hole, the pre-cutting hole correction method further includes: The fluctuation difference between the negative weight deviation at the head and the negative weight deviation at the tail of the product is calculated. If the fluctuation difference is greater than 0.6%, the tension between the rolling mills is reduced.

3. The pre-cutting hole type correction method according to claim 1, characterized in that, The rolling hole includes a cutting hole and a forming hole, and the step of obtaining the total elongation of the rolled piece through the rolling hole includes: Obtain the first elongation of the rolled piece through the slitting hole; Obtain the second elongation of the rolled piece through the forming hole; Multiply the first elongation and the second elongation to obtain the total elongation.

4. The pre-cutting hole type correction method according to claim 3, characterized in that, The step of obtaining the first elongation of the rolled piece through the slitting hole includes: Measure the first cross-sectional area of ​​the rolled piece before it passes through the slitting hole; Measure the second cross-sectional area of ​​the rolled piece after passing through the slitting hole; Divide the first cross-sectional area by the second cross-sectional area to obtain the first elongation.

5. The pre-cutting hole type correction method according to claim 3, characterized in that, The step of obtaining the first elongation of the rolled piece through the slitting hole includes: Measure the first length of the rolled piece before it passes through the slitting hole; Measure the second length of the rolled piece after passing through the slitting hole; Divide the second length by the first length to obtain the first elongation.

6. The pre-cutting hole pattern correction method according to claim 3, characterized in that, The number of forming holes is multiple, and the step of obtaining the second elongation of the rolled piece through the forming holes includes: Obtain the partial elongation of the rolled piece through each of the forming holes; The second elongation is obtained by multiplying the multiple elongation ratios together.

7. The pre-cutting hole type correction method according to claim 1, characterized in that, The step of calculating the area reduction value of the pre-cut holes based on the total elongation, the nominal cross-sectional area, the difference, and the number of pre-cut holes includes: The reduction in area was calculated using a formula, which is: S1 = S2 × λ ​​× a × n; In the formula, S1 is the area reduction value, S2 is the nominal cross-sectional area, λ is the total elongation, a is the difference, and n is the number of segments.

8. The pre-cutting hole type correction method according to claim 1, characterized in that, In the step of calculating the area reduction value of the pre-splitting hole based on the total elongation, the nominal cross-sectional area, the difference, and the number of pre-splitting holes, the number of segments is three.

9. The pre-cutting hole type correction method according to claim 1, characterized in that, The hole shape parameters include the parallel circle spacing, the groove bottom curvature, and the hole sidewall inclination angle. The step of correcting the hole shape parameters of the pre-cut hole based on the area reduction value includes: Reduce the spacing between the parallel circles; Reduce the curvature of the groove bottom; The inclination angle of the hole sidewall is reduced.

10. The pre-cutting hole type correction method according to claim 9, characterized in that, The hole shape parameters also include hole height and groove radius, and the step of correcting the hole shape parameters of the pre-cut hole based on the area reduction value further includes: Reduce the height of the hole; Increase the radius of the groove.

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