Method, device and equipment for acquiring tension set value of cold-rolled strip steel

Abstract

The invention relates to the technical field of steel rolling, and discloses a method, device and equipment for acquiring a tension set value of cold-rolled strip steel. The method comprises the steps that rolling process parameters are obtained; setting an inlet tensile stress condition, an outlet tensile stress condition and a roll gap front sliding area proportion critical value based on rolling process parameters; calculating a roll gap front sliding area proportion under an inlet tensile stress condition and an outlet tensile stress condition; whether the roll gap front sliding area proportion reaches a preset roll gap front sliding area proportion critical value or not is judged; and when a preset roll gap front sliding area proportion critical value is reached, inlet tension and outlet tension are calculated according to the inlet tensile stress and the outlet tensile stress which are output through iterative updating. On the basis of the quantitative relation between the cold-rolled strip steel rolling inlet and outlet tensile stress and the roll gap front slip area proportion, the roll gap front slip area proportion is adjusted to the critical value by continuously iteratively optimizing the inlet and outlet tensile stress, iterative calculation is stable and rapid and is used for presetting calculation of inlet and outlet tension, it is guaranteed that the roll gap does not slip in the rolling process, and the rolling quality is improved. The production stability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of steel rolling, and in particular to a method, device and equipment for obtaining a tension setting value of a cold-rolled steel strip. Background Art

[0002] With the increase of cold rolling speed of strip steel, the temperature and friction conditions of the roll gap deformation zone will become very complicated, which will easily form hot slip damage and scratches on the surface of the strip steel, seriously reducing the surface quality and product grade of the product. This type of defect is caused by roll gap slip during rolling, that is, the linear speed of the roll exceeds the exit speed of the strip steel, and relative slip occurs between the strip steel and the roll. In essence, the roll gap deformation zone is completely replaced by the back slip zone, the front slip zone disappears, and the neutral surface appears outside the roll gap deformation zone. Therefore, in order to avoid roll gap slip during rolling, it is necessary to ensure that there is a certain proportion of front slip zone in the roll gap. The strip steel rolling entrance tension and exit tension are important factors affecting the formation of the roll gap front slip zone. After the relevant process parameters such as roll diameter, strip steel entrance thickness and exit thickness, roll gap lubrication state and other conditions are determined, it is necessary to consider the influence of strip steel tension on roll gap slip, and then determine the setting value of strip steel rolling entrance tension and exit tension. Summary of the invention

[0003] The main purpose of the present invention is to provide a method, device and equipment for obtaining the tension setting value of cold-rolled strip, aiming to solve at least one of the above-mentioned technical problems.

[0004] To achieve the above object, the present invention provides a method for obtaining a set value of tension of a cold-rolled strip, comprising:

[0005] Obtain rolling process parameters of cold-rolled strip steel;

[0006] Based on the rolling process parameters, an inlet tensile stress condition, an outlet tensile stress condition and a critical value of the ratio of the front slip zone of the roll gap are set;

[0007] Calculating the ratio of the front slip zone of the roller gap under the inlet tensile stress condition and the outlet tensile stress condition;

[0008] Determining whether the ratio of the front sliding area of ​​the roller gap reaches a preset critical value of the front sliding area of ​​the roller gap;

[0009] When the ratio of the front slip zone of the roll gap reaches a preset critical value of the front slip zone of the roll gap, the inlet tension and the outlet tension are calculated respectively according to the inlet tensile stress and the outlet tensile stress output by iterative updating.

[0010] In some embodiments, the setting of the entrance tensile stress condition, the exit tensile stress condition and the critical value of the ratio of the front slip zone of the roll gap based on the rolling process parameters includes:

[0011] Obtaining the inlet strip yield strength and the outlet strip yield strength according to the rolling process parameters;

[0012] Setting the initial value, minimum value and maximum value of the entrance tensile stress according to different preset multiples and the product of the entrance strip yield strength;

[0013] The initial value, minimum value and maximum value of the inlet tensile stress are used as inlet tensile stress conditions;

[0014] Setting the initial value, minimum value and maximum value of the outlet tensile stress according to different preset multiples and the product of the outlet strip yield strength;

[0015] The initial value, minimum value and maximum value of the outlet tensile stress are used as outlet tensile stress conditions;

[0016] Set the critical value of the roller gap front slip area ratio.

[0017] In some embodiments, the initial value of the entrance tensile stress is 0.1 times the entrance strip yield strength, the minimum value is 0.02 times the entrance strip yield strength, and the maximum value is 0.3 times the entrance strip yield strength; the initial value of the exit tensile stress is 0.1 times the exit strip yield strength, the minimum value is 0.02 times the exit strip yield strength, and the maximum value is 0.3 times the exit strip yield strength; the critical value of the roller gap front slip zone ratio ranges from 0.1 to 0.5.

[0018] In some embodiments, the calculating the ratio of the front sliding area of ​​the roller gap under the inlet tensile stress condition and the outlet tensile stress condition includes:

[0019] Setting an initial roll profile curve under the inlet tensile stress condition and the outlet tensile stress condition, and determining the inlet position of the rolled piece;

[0020] Calculate the unit pressure of each section of the rear sliding zone from the entrance to the exit based on the entrance position of the rolled piece;

[0021] Calculate the unit pressure of each section in the forward sliding zone from the outlet to the inlet;

[0022] Determine the unit pressure distribution of each section in the roll gap deformation zone according to the unit pressure of each section in the rear sliding zone and the unit pressure of each section in the front sliding zone;

[0023] Calculating the roll gap thickness distribution according to the unit pressure distribution of each section;

[0024] Determining whether the roll gap thickness distributions obtained from two adjacent calculations converge;

[0025] The roll gap thickness distribution is calculated when convergence occurs, otherwise the next round of iterative calculation is performed until the roll gap thickness distribution converges;

[0026] After the iteration converges, the ratio of the front sliding area of ​​the roll gap is obtained according to the unit pressure distribution of each section and the boundary section between the front sliding area and the rear sliding area.

[0027] In some embodiments, the determining whether the ratio of the front sliding area of ​​the roller gap reaches a preset critical value of the front sliding area of ​​the roller gap comprises:

[0028] Set the precision coefficient;

[0029] A judgment value is obtained according to the product of the accuracy coefficient and a preset roller gap front sliding area ratio critical value;

[0030] Calculating the difference between the roller gap front slip zone ratio and the preset roller gap front slip zone ratio critical value;

[0031] comparing the absolute value of the difference with the judgment value;

[0032] If the absolute value of the difference is less than or equal to the judgment value, it is determined that the ratio of the front slip area of ​​the roller gap reaches a preset critical value of the front slip area of ​​the roller gap.

[0033] In some embodiments, after determining whether the ratio of the front sliding area of ​​the roller gap reaches a preset critical value of the front sliding area of ​​the roller gap, the method further includes:

[0034] When the ratio of the front sliding area of ​​the roller gap does not reach a preset critical value of the front sliding area of ​​the roller gap, judging whether the current outlet tensile stress reaches the maximum value of the outlet tensile stress;

[0035] If the current outlet tensile stress does not reach the maximum outlet tensile stress value, the current outlet tensile stress is updated by using the secant method, and the step of calculating the ratio of the front slip zone of the roll gap under the conditions of the inlet tensile stress and the outlet tensile stress is returned to until the ratio of the front slip zone of the roll gap reaches a preset critical value of the ratio of the front slip zone of the roll gap;

[0036] If the current outlet tensile stress reaches the maximum value of the outlet tensile stress, the current outlet tensile stress is set as the maximum value of the outlet tensile stress, and the inlet tensile stress is updated by the secant method, and the step of calculating the ratio of the front slip area of ​​the roller gap under the inlet tensile stress condition and the outlet tensile stress condition is returned to until the ratio of the front slip area of ​​the roller gap reaches the preset critical value of the front slip area of ​​the roller gap.

[0037] In some embodiments, the updating of the current outlet tensile stress by using the secant method includes:

[0038] Setting proportional relationships based on the secant method;

[0039] Get the outlet tensile stress increment after iterative calculation;

[0040] The current outlet tensile stress is iteratively updated according to the outlet tensile stress increment and the proportional relationship to obtain a revised outlet tensile stress.

[0041] In some embodiments, the rolling process parameters include the inlet thickness of the strip, the outlet thickness of the strip, the width of the strip, the inlet strip yield strength, the outlet strip yield strength, the working roll diameter and the roll gap friction coefficient.

[0042] In addition, to achieve the above-mentioned purpose, the present invention also proposes a device for obtaining a set value of a tension of a cold-rolled strip, comprising:

[0043] A parameter acquisition module is used to obtain rolling process parameters of cold-rolled strip steel;

[0044] A condition setting module, used to set an inlet tensile stress condition, an outlet tensile stress condition and a critical value of the ratio of the front slip zone of the roll gap based on the rolling process parameters;

[0045] A ratio calculation module, used for calculating the ratio of the front sliding area of ​​the roller gap under the inlet tensile stress condition and the outlet tensile stress condition;

[0046] A critical judgment module is used to judge whether the ratio of the front slip zone of the roll gap reaches a preset critical value of the front slip zone of the roll gap;

[0047] The tension calculation module is used to calculate the inlet tension and the outlet tension respectively according to the inlet tensile stress and the outlet tensile stress output by iterative update when the ratio of the front slip area of ​​the roller gap reaches a preset critical value of the front slip area of ​​the roller gap.

[0048] In addition, to achieve the above-mentioned purpose, the present invention also proposes an electronic device, which includes: a memory, a processor, and a cold-rolled strip tension setting value acquisition program stored in the memory and runnable on the processor, wherein the cold-rolled strip tension setting value acquisition program is configured to implement the cold-rolled strip tension setting value acquisition method as described above.

[0049] The present invention provides a method for obtaining a tension setting value of a cold-rolled steel strip, comprising: obtaining rolling process parameters of the cold-rolled steel strip; setting an inlet tensile stress condition, an outlet tensile stress condition and a critical value of a ratio of a front slip zone of a roll gap based on the rolling process parameters; calculating a ratio of a front slip zone of a roll gap under the inlet tensile stress condition and the outlet tensile stress condition; judging whether the ratio of a front slip zone of a roll gap reaches a preset critical value of a ratio of a front slip zone of a roll gap; and when the ratio of a front slip zone of a roll gap reaches a preset critical value of a ratio of a front slip zone of a roll gap, respectively calculating an inlet tension and an outlet tension according to the inlet tensile stress and the outlet tensile stress outputted by iterative updating. In the present invention, based on the established quantitative relationship between the inlet tensile stress, the outlet tensile stress and the ratio of a front slip zone of a roll gap of a cold-rolled steel strip, the inlet tensile stress and the outlet tensile stress are continuously iterated to optimize, and the ratio of a front slip zone of a roll gap is adjusted to a critical value range, and the iterative calculation is stable and fast, and can be used for the preset calculation of the inlet tension and the outlet tension of a cold-rolled steel strip, thereby ensuring that the roll gap does not slip during the rolling process, and improving production stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A schematic diagram of the structure of an electronic device in a hardware operating environment involved in an embodiment of the present invention;

[0051] Figure 2 It is a flow chart of an embodiment of a method for obtaining a tension setting value of a cold-rolled steel strip according to the present invention;

[0052] Figure 3 This is an example flow chart of a method for obtaining a cold-rolled strip tension setting value according to an embodiment of the present invention;

[0053] Figure 4 A schematic diagram of the calculation principle of the secant method involved in the embodiment of the present invention;

[0054] Figure 5 It is a structural block diagram of an embodiment of a device for acquiring a tension setting value of a cold-rolled steel strip according to the present invention.

[0055] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0058] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0059] Reference Figure 1, Figure 1 The figure is a schematic diagram of the structure of an electronic device of the hardware operating environment involved in the embodiment of the present invention.

[0060] like Figure 1 As shown, the electronic device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a wireless fidelity (Wireless-Fidelity, Wi-Fi) interface). The memory 1005 may be a high-speed random access memory (Random Access Memory, RAM memory) or a stable non-volatile memory (Non-Volatile Memory, NVM), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0061] Those skilled in the art will understand that Figure 1 The structure shown in the figure does not constitute a limitation on the electronic device, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0062] like Figure 1 As shown, the memory 1005 as a storage medium may include an operating system, a network communication module, a user interface module, and a cold-rolled strip tension setting value acquisition program.

[0063] exist Figure 1 In the electronic device shown, the network interface 1004 is mainly used for data communication with a network server; the user interface 1003 is mainly used for data interaction with a user; the processor 1001 and the memory 1005 in the electronic device of the present invention can be set in the electronic device, and the electronic device calls the cold-rolled strip tension setting value acquisition program stored in the memory 1005 through the processor 1001, and executes the cold-rolled strip tension setting value acquisition method provided in an embodiment of the present invention.

[0064] The present invention provides a method, a device and equipment for obtaining a tension setting value of a cold-rolled steel strip.

[0065] The embodiment of the present invention provides a method for obtaining a set value of the tension of a cold-rolled steel strip, referring to Figure 2 , Figure 2It is a flow chart of an embodiment of a method for obtaining a tension setting value of a cold-rolled steel strip according to the present invention.

[0066] like Figure 2 As shown, the method for obtaining the cold-rolled strip tension setting value comprises:

[0067] Step S100: obtaining rolling process parameters of cold-rolled steel strip;

[0068] Step S200: setting an inlet tensile stress condition, an outlet tensile stress condition and a critical value of the ratio of the front slip zone of the roll gap based on the rolling process parameters;

[0069] Step S300: calculating the ratio of the front sliding area of ​​the roller gap under the inlet tensile stress condition and the outlet tensile stress condition;

[0070] Step S400: determining whether the ratio of the front sliding area of ​​the roller gap reaches a preset critical value of the front sliding area of ​​the roller gap;

[0071] Step S500: when the ratio of the front slip zone of the roll gap reaches a preset critical value of the front slip zone of the roll gap, the inlet tension and the outlet tension are calculated respectively according to the inlet tensile stress and the outlet tensile stress output by iterative updating.

[0072] It should be noted that the execution subject in this embodiment may be an electronic device, which may be a computer device with data processing functions, or other devices that can achieve the same or similar functions. This embodiment does not limit this. In this embodiment, a computer device is used as an example for explanation.

[0073] In one embodiment, rolling process parameters of the cold-rolled steel strip are obtained, including but not limited to strip inlet thickness, strip outlet thickness, strip width, inlet strip yield strength, outlet strip yield strength, working roll diameter, and roll gap friction coefficient.

[0074] Specifically, the rolling process parameters of the cold-rolled steel strip are obtained, including but not limited to the strip inlet thickness h 0 , outlet thickness h 1 , strip width B, inlet strip yield strength σ s0 , Export strip yield strength σ s1 , working roll diameter D and roll gap friction coefficient μ.

[0075] In one embodiment, an inlet tensile stress condition, an outlet tensile stress condition and a critical value of the ratio of the sliding zone before the roll gap are set based on the rolling process parameters, including: obtaining the inlet strip yield strength and the outlet strip yield strength according to the rolling process parameters; setting the initial value, minimum value and maximum value of the inlet tensile stress according to different preset multiples and the product of the inlet strip yield strength; using the initial value, minimum value and maximum value of the inlet tensile stress as the inlet tensile stress condition; setting the initial value, minimum value and maximum value of the outlet tensile stress according to different preset multiples and the product of the outlet strip yield strength; using the initial value, minimum value and maximum value of the outlet tensile stress as the outlet tensile stress condition; and setting the critical value of the ratio of the sliding zone before the roll gap.

[0076] In one embodiment, the initial value of the entrance tensile stress is 0.1 times the entrance strip yield strength, the minimum value is 0.02 times the entrance strip yield strength, and the maximum value is 0.3 times the entrance strip yield strength; the initial value of the exit tensile stress is 0.1 times the exit strip yield strength, the minimum value is 0.02 times the exit strip yield strength, and the maximum value is 0.3 times the exit strip yield strength; the critical value of the roller gap front slip zone ratio ranges from 0.1 to 0.5.

[0077] Specifically, the initial value of the inlet tensile stress is set Minimum value t 0min and the maximum value t 0max , the initial value of the outlet tensile stress Minimum value t 1min and the maximum value t 1max , and the critical value of the front slip zone ratio of the roller gap η 0 .

[0078] Exemplarily, the initial value of the inlet tensile stress is set to 0.1σ s0 , minimum value t 0min 0.02σ s0 , maximum value t 0max 0.3σ s0 , set the outlet tensile stress The initial value is 0.1σ s1 , minimum value t 1min 0.02σ s1 , maximum value t 1max 0.3σ s1 The critical value of the ratio of the front slip zone of the roll gap is η 0 The range is 0.1 to 0.5. In this embodiment, the critical value η of the ratio of the front sliding area of ​​the roller gap is set 0 Take 0.15 as an example for explanation.

[0079] In one embodiment, the ratio of the front slip zone of the roll gap is calculated under the inlet tensile stress condition and the outlet tensile stress condition, including: setting an initial roll profile curve under the inlet tensile stress condition and the outlet tensile stress condition, and determining the inlet position of the rolled piece; calculating the unit pressure of each section of the rear slip zone from the inlet to the outlet based on the inlet position of the rolled piece; calculating the unit pressure of each section of the front slip zone from the outlet to the inlet; determining the unit pressure distribution of each section of the roll gap deformation zone according to the unit pressure of each section of the rear slip zone and the unit pressure of each section of the front slip zone; calculating the roll gap thickness distribution according to the unit pressure distribution of each section; judging whether the roll gap thickness distribution obtained by two adjacent calculations converges; calculating the roll gap thickness distribution when converged, otherwise entering the next round of iterative calculation until the roll gap thickness distribution converges; after the iteration converges, obtaining the ratio of the front slip zone of the roll gap according to the unit pressure distribution of each section and the boundary section between the front slip zone and the rear slip zone.

[0080] Specifically, the ratio η of the front slip zone of the roll gap under the set inlet tensile stress and outlet tensile stress conditions is calculated.

[0081] It should be noted that the ratio of the slip zone before the roll gap refers to the ratio of the area where the metal undergoes plastic deformation before entering the roll gap relative to the entire roll gap length during the metal rolling process. This ratio is very important for controlling the rolling process and product quality. There are many ways to calculate the ratio of the slip zone before the roll gap. The following is an example calculation method for calculating the ratio of the slip zone before the roll gap.

[0082] In one example, step S300 includes:

[0083] S301, setting the initial roll profile curve and determining the entry position of the rolled piece.

[0084] Assume that the roller is not deformed and is in an arc shape, and δ(x) = 0. Discrete the deformation zone: divide the deformation zone into n segments (such as n = 1000), and the roll gap thickness model equation under the arc-shaped roller profile is: Where x(i) is the horizontal coordinate of the i-th section, h(i) is the thickness of the rolled piece in the i-th section, x(n) = 0, h(n) = h 1 ,therefore Discrete segment length R is the radius of the working roll, and R is half of the diameter D of the working roll.

[0085] S302, calculating the unit pressure of each section of the rear sliding area from the inlet to the outlet. Specifically:

[0086] Using the back-slip zone formula to calculate from the inlet to the outlet, the unit pressure of the inlet section (section 1) under sliding friction conditions is calculated as Use Aitken iteration method to solve p(1) b , where t 0is the entrance tensile stress (the entrance tensile stress updated by the current iteration), in MPa; K is the deformation resistance, in MPa; μ is the roller gap friction coefficient.

[0087] The stress differential equation of the rear sliding zone under the sliding friction condition is used to calculate the unit pressure of the second, third to nth sections in sequence. Specifically, the stress differential equation of the rear sliding zone under the sliding friction condition is written into a differential form:

[0088]

[0089] Arranged:

[0090]

[0091] The friction stress in the rear sliding zone under sliding friction conditions is: t(i) b _sli=μp(i) b _sli.

[0092] S303, calculating the unit pressure of each section of the front sliding zone from the exit to the entrance. Similar to the calculation method of the rear sliding zone, specifically: using the formula of the front sliding zone to calculate from the exit to the entrance, the unit rolling pressure of the exit section (nth section) under the sliding friction condition is calculated as Aitken iteration method is used to solve it; where t 1 is the outlet tensile stress (the outlet tensile stress updated by the current iteration), in MPa; K is the deformation resistance, in MPa; μ is the roller gap friction coefficient.

[0093] The stress differential equation of the front sliding zone under the sliding friction condition is used to calculate the unit pressure of the n-1 section, the n-2 section to the 1st section in sequence. Specifically, the stress differential equation of the front sliding zone under the sliding friction condition is written into a differential form:

[0094]

[0095] Arranged:

[0096]

[0097] Use Aitken iteration method to solve p(i) f _sli.

[0098] The friction stress in the front sliding zone under sliding friction conditions is: t(i) f _sli=-μp(i) f _sli, the negative sign indicates that the friction stress direction in the front slip zone is toward the entrance side (opposite to the rolling direction).

[0099] S304, determining the unit pressure of each section of the roll gap deformation zone.

[0100] Compare the two sets of unit pressures p(1) calculated using the front sliding zone formula and the rear sliding zone formula f 、p(2) f ...p(n) f and p(1) b 、p(2) b ...p(n) b , find the segment with the smallest difference (assuming it is the rth segment), then this segment is the boundary between the front slip zone and the back slip zone (i.e. the neutral surface), x(r) = x(1) + (r-1)ΔX. Keep p(1) f 、p(2) f ..., p(r-1) f 、p(r) f or p(r) b 、p(r+1) b ...p(n) b So far, the unit pressure distribution under the specified roll profile has been calculated, that is, p(1) = p(1) f 、p(2)=p(2) f ..., p(r-1) = p(r-1) f 、p(r)=p(r) f Or p(r)=p(r) b 、p(r+1)=p(r+1) b ...p(n)=p(n) b .

[0101] S305, calculating the roll gap thickness distribution based on the unit pressure distribution.

[0102] The roll gap thickness h(i) is calculated using the unit pressure distribution. However, in order to ensure convergence, a smoothing coefficient (relaxation factor) e is introduced here to make the unit pressure of each section calculated in the previous and next two iterations change smoothly.

[0103] That is, p m+1 (i) = ep(i) + (1-e)p m (i), 0<e<1

[0104] Where p(i) is the calculated unit pressure distribution under the specified roll profile; p m (i) is the unit pressure distribution used in the mth iteration; p m+1 (i) is the unit pressure distribution used in the m+1th iteration.

[0105] Using the relaxed unit pressure distribution p m+1 (i) Calculate the elastic flattening deformation of the roller δ(x(j)) and calculate the elastic flattening deformation of the roller at the horizontal coordinate x(j) by the cumulative summation method j=1,2,3…n,si The unit pressure p m +1 (i) Corresponding horizontal axis.

[0106] Then the distribution of the deformed roll profile curve is obtained as:

[0107]

[0108] The roll gap thickness distribution is:

[0109] In the formula, y(x(j)) min It is the ordinate corresponding to the lowest point of the deformed roller profile curve, in mm.

[0110] S306, judging whether the roll gap thickness distributions obtained by the two calculations converge.

[0111] S307, when convergence occurs, calculate and obtain the roll gap thickness distribution, otherwise enter the next round of iterative calculation until the roll gap thickness distribution converges.

[0112] Corresponding to the unit pressure distribution, the roll gap thickness is "relaxed", that is, h m+1 (j) = eh(j) + (1 - e)h m (j)

[0113] Where h(j) is the calculated roll gap thickness of each section; h m (j) is the thickness of each roll gap used in the mth iteration; h m+1 (j) is the thickness of each roll gap used in the m+1th iteration.

[0114] Then, using the new roll gap thickness distribution (h m+1 (j)) Use the same method as above to solve the unit pressure distribution and friction stress distribution under the roller profile again, and repeat this cycle until convergence. The convergence condition is: the difference between the corresponding roller gap thickness calculated twice before and after is less than the accuracy value, that is, h(j)-h m (j)≤ε×h(j), ε is the convergence accuracy, for example, ε=0.001.

[0115] S308, after the iteration converges, all the unit pressure distributions p(1), p(2), p(3), ... p(n) that meet the conditions have been calculated, and the boundary section between the front slip zone and the rear slip zone (the rth section, i.e., the neutral surface), x(r) = x(1) + (r-1) ΔX, then the ratio of the front slip zone

[0116] It can be understood that, in another example, the general steps for calculating the ratio of the front slip zone of the roll gap include: defining relevant parameters: such as the total length of the roll gap, the plastic deformation length of the metal in the roll gap, that is, the distance that the metal undergoes plastic deformation after entering the roll gap, the length of the metal in the front slip zone of the roll gap, etc.; calculating the length of the front slip zone: the length of the front slip zone can usually be obtained by measurement or calculation based on the plastic deformation characteristics of the material. For example, it can be assumed that the length of the front slip zone is related to factors such as the plasticity of the material, the roll gap pressure and the roll speed; calculating the ratio of the front slip zone based on the total length of the roll gap, the length of the front slip zone and the plastic deformation length of the metal in the roll gap.

[0117] In practical applications, the calculation method of the front slip zone ratio of the roll gap involves physical phenomena and mechanical principles in the metal rolling process. The calculation method of the front slip zone ratio of the roll gap includes but is not limited to: calculation based on the rolling force model: by establishing a mathematical model of the rolling force, factors such as the elasticity, plastic deformation and friction of the material can be considered to calculate the front slip zone ratio. Calculation based on the material flow law, according to the material flow law, such as the Coulomb friction model, the flow of metal in the roll gap can be calculated. Exemplarily, the method includes the following steps: calculating the equivalent plastic strain of the metal during the rolling process; determining the length of the front slip zone using the relationship with the roll gap length; calculating the front slip zone ratio. Empirical formula method: based on a large amount of experimental data, some empirical formulas can be summarized to estimate the front slip zone ratio, for example, the front slip zone ratio of the roll gap is calculated based on the thickness difference before and after rolling, the material thickness before rolling, and the empirical coefficient. Numerical simulation method: By using finite element analysis (FEA) or finite volume method (FVM) to numerically simulate the rolling process, the flow of metal in the roll gap can be obtained, thereby calculating the proportion of the front slip zone. For example, by simulating the rolling process with finite element software, the stress-strain field of the metal can be obtained, and the length of the front slip zone can be further calculated. Artificial intelligence method: Using machine learning or deep learning algorithms, based on a large amount of rolling data and corresponding test results, a model is trained to predict the proportion of the front slip zone. In practical applications, it may be necessary to combine multiple methods, or to improve and adjust a specific method to adapt to actual conditions, which is not limited in this embodiment.

[0118] Exemplarily, the Aitken iteration method (Aitken acceleration method) is used to accelerate the convergence of a linear sequence, especially to improve the speed of iterative convergence when solving equations in numerical analysis. This method is used to optimize the iterative process. When using the Aitken iteration method to solve a physical problem involving pressure, it is necessary to convert the mathematical model of the problem into a form that can be solved by the iterative method, so that the Aitken acceleration method can be used for iterative calculation.

[0119] In one embodiment, judging whether the ratio of the front slip area of ​​the roll gap reaches a preset critical value of the front slip area of ​​the roll gap, includes: setting an accuracy coefficient; obtaining a judgment value according to the product of the accuracy coefficient and the preset critical value of the front slip area of ​​the roll gap; calculating the difference between the ratio of the front slip area of ​​the roll gap and the preset critical value of the front slip area of ​​the roll gap; comparing the absolute value of the difference with the judgment value; if the absolute value of the difference is less than or equal to the judgment value, determining that the ratio of the front slip area of ​​the roll gap reaches the preset critical value of the front slip area of ​​the roll gap.

[0120] In one embodiment, after determining whether the ratio of the front slip zone of the roll gap has reached a preset critical value of the ratio of the front slip zone of the roll gap, the method further includes: when the ratio of the front slip zone of the roll gap has not reached a preset critical value of the ratio of the front slip zone of the roll gap, determining whether the current outlet tensile stress has reached a maximum value of the outlet tensile stress; if the current outlet tensile stress has not reached a maximum value of the outlet tensile stress, updating the current outlet tensile stress by the secant method, and returning to the step of calculating the ratio of the front slip zone of the roll gap under the conditions of the inlet tensile stress and the outlet tensile stress, until the ratio of the front slip zone of the roll gap reaches a preset critical value of the ratio of the front slip zone of the roll gap; if the current outlet tensile stress has reached a maximum value of the outlet tensile stress, setting the current outlet tensile stress as the maximum value of the outlet tensile stress, updating the inlet tensile stress by the secant method, and returning to the step of calculating the ratio of the front slip zone of the roll gap under the conditions of the inlet tensile stress and the outlet tensile stress, until the ratio of the front slip zone of the roll gap reaches a preset critical value of the ratio of the front slip zone of the roll gap.

[0121] Specifically, Figure 3 As shown, it is judged whether the calculated roller gap front slip area ratio η meets the set roller gap front slip area ratio critical value η 0 : If the condition is satisfied, the calculation ends; if not, it is determined whether the outlet tensile stress has reached the maximum value. If the outlet tensile stress value has not reached the maximum value, the outlet tensile stress is increased, and then the calculation is transferred to step S300 to recalculate until the above conditions are met. If the outlet tensile stress has reached the maximum value, the outlet tensile stress is set to the maximum value t 1max , and reduce the entrance tensile stress, and then go to step S300 to recalculate until the above conditions are met.

[0122] For example, it is determined whether the calculated roller gap front slip area ratio η satisfies the set roller gap front slip area ratio critical value η. 0 , specifically when η-η 0 |≤γ×η 0 This condition is considered to be satisfied when , where γ is the precision coefficient, which can be taken as γ = 0.001. Figure 3As shown, if the conditions are met, the calculation ends; if not, it is determined whether the outlet tensile stress has reached the maximum value. If the outlet tensile stress has not reached the maximum value, the outlet tensile stress is increased, specifically, the secant method is used to calculate a new outlet tensile stress value, and then the process proceeds to step S300 to recalculate until the above conditions are met. If the outlet tensile stress has reached the maximum value, the outlet tensile stress is set to the maximum value, and the inlet tensile stress is reduced, specifically, the secant method is used to calculate a new inlet tensile stress, and then the process proceeds to step S300 to recalculate until the above conditions are met.

[0123] In one embodiment, the current outlet tensile stress is updated using the secant method, including: setting a proportional relationship based on the secant method; obtaining an outlet tensile stress increment after iterative calculation; iteratively updating the current outlet tensile stress according to the outlet tensile stress increment and the proportional relationship to obtain a corrected outlet tensile stress.

[0124] It should be noted that the calculation principle of the secant method is as follows, taking the calculation of the iteratively updated outlet tensile stress as an example. Figure 4 As shown, from the proportional relationship we can know:

[0125]

[0126] Assume that the outlet tensile stress increment (correction) after the first iteration calculation of this iterative calculation cycle is Δt 1 (1) , for example, we can take Δt 1 (1) =5, from the above derivation we can know:

[0127] When m = 1, t 1 (2) =t 1 (1) +Δt 1 (1) ; When m ≥ 2,

[0128] Among them, η 0 is the critical value of the ratio of the front sliding area of ​​the roll gap; η (m) is the ratio of the front sliding area of ​​the roll gap calculated in the mth iteration; η (m-1) is the ratio of the front slip area of ​​the roller gap calculated in the m-1th iteration; Δt 1 (m-1) is the outlet tensile stress increment (correction) obtained after the m-1th iteration calculation; Δt 1 (m) is the outlet tensile stress increment (correction) obtained after the mth iteration calculation;

[0129] Then the new outlet tensile stress after correction is:

[0130] t1 =t 1 (m+1) =t 1 (m) +Δt 1 (m)

[0131] It should be noted that the principle of the secant method used to calculate the updated inlet tensile stress is the same as the above steps and will not be repeated here.

[0132] In one embodiment, the inlet tension and the outlet tension are calculated respectively according to the inlet tensile stress and the outlet tensile stress output by iterative updating.

[0133] Specifically, during continuous rolling or stretching, the material usually experiences tensile stress. Tensile stress refers to the force per unit area of ​​the material under tension. Tension is the total force acting on the entire cross-section of the material. Based on the tensile stress at the inlet and outlet, the corresponding tension can be calculated:

[0134] T=σ·A

[0135] Where T is tension; σ is tensile stress; and A is the cross-sectional area of ​​the material.

[0136] For example, according to the inlet tensile stress σ in and the outlet tensile stress σ out , and the cross-sectional area A of the material in and A out (The cross-sectional areas at the inlet and outlet may be different due to the stretching of the material), the inlet tension T can be calculated separately in and outlet tension T out .

[0137] It should be noted that the feasibility of the method described in this embodiment is further illustrated by two examples below. For example, the working roll diameters of the two examples are both 70 mm, the strip widths are both 1200 mm, and the strip inlet thickness, outlet thickness, roll gap friction coefficient, inlet strip yield strength, and outlet strip yield strength are shown in the 2nd to 6th columns of Table 1, respectively.

[0138] Table 1 Calculation parameters and iterative calculation results of two examples

[0139]

[0140] For the first example, the initial value of the inlet tensile stress is 54.6MPa, the initial value of the outlet tensile stress is 82.6MPa, and the calculated front slip zone ratio is 0.0348, which is less than the set critical value of 0.15. In the subsequent iterative calculation process, the outlet tensile stress is first increased. When the outlet tensile stress calculated by the secant method is 139MPa (less than the maximum value of the outlet tensile stress 247.8MPa), the further calculated front slip zone ratio is 0.1502, which meets the calculation requirements. In this way, the inlet tension of the example can be further calculated from the inlet tensile stress to be 151kN, and the outlet tension of the example can be further calculated from the outlet tensile stress to be 250kN.

[0141] For the second example, the initial value of the inlet tensile stress is 82.6MPa, the initial value of the outlet tensile stress is 101.2MPa, and the calculated front slip zone ratio is 0.0659, which is less than the set critical value of 0.15. In the subsequent iterative calculation process, the outlet tensile stress is first increased. When the outlet tensile stress calculated by the secant method is the maximum value of 303.6MPa, the further calculated front slip zone ratio is 0.136, which is still less than the set critical value of 0.15. Thereafter, the outlet tensile stress is set to the maximum value of 303.6MPa, and the inlet tensile stress is reduced. When the inlet tensile stress calculated by the secant method is 49.6MPa (greater than the minimum inlet tensile stress of 16.5MPa), the further calculated front slip zone ratio is 0.1512, which meets the calculation requirements. In this way, the inlet tension of the example can be further calculated from the inlet tensile stress to be 89kN, and the outlet tension of the example can be further calculated from the outlet tensile stress to be 357kN.

[0142] It can be understood that the purpose of this embodiment is to provide a method for obtaining a set value of tension for cold-rolled strip steel, which is used for the pre-setting calculation of the entrance tension and exit tension of cold-rolled strip steel rolling, so as to solve the problem of unstable production caused by roll gap slippage during rolling. The method described in this embodiment is based on the established quantitative relationship between the entrance tension and exit tension of cold-rolled strip steel rolling and the ratio of the front slip zone of the roll gap. By continuously iteratively optimizing the entrance tension and exit tension, the ratio value of the front slip zone of the roll gap is adjusted to the critical value range, thereby ensuring that the roll gap does not slip during rolling and improving production stability. The principle of the method described in this embodiment is clear and definite, and the iterative calculation is stable and fast, and can be used for the pre-setting calculation of the entrance tension and exit tension of cold-rolled strip steel rolling.

[0143] The present embodiment provides a method for obtaining a tension setting value of a cold-rolled steel strip, comprising: obtaining rolling process parameters of the cold-rolled steel strip; setting an inlet tensile stress condition, an outlet tensile stress condition, and a critical value of the ratio of the front slip zone of the roll gap based on the rolling process parameters; calculating the ratio of the front slip zone of the roll gap under the inlet tensile stress condition and the outlet tensile stress condition; judging whether the ratio of the front slip zone of the roll gap reaches a preset critical value of the ratio of the front slip zone of the roll gap; and when the ratio of the front slip zone of the roll gap reaches a preset critical value of the ratio of the front slip zone of the roll gap, respectively calculating the inlet tension and the outlet tension according to the inlet tensile stress and the outlet tensile stress outputted by iterative updating. In the present embodiment, based on the established quantitative relationship between the inlet tensile stress, the outlet tensile stress, and the ratio of the front slip zone of the roll gap of the cold-rolled steel strip, the ratio of the front slip zone of the roll gap is adjusted to the critical value range by continuously iteratively optimizing the inlet tensile stress and the outlet tensile stress, and the iterative calculation is stable and fast, and can be used for the preset calculation of the inlet tension and the outlet tension of the cold-rolled steel strip, thereby ensuring that the roll gap does not slip during the rolling process and improving the production stability.

[0144] In addition, an embodiment of the present invention also proposes a storage medium, on which a cold-rolled strip tension setting value acquisition program is stored. When the cold-rolled strip tension setting value acquisition program is executed by a processor, the steps of the cold-rolled strip tension setting value acquisition method described above are implemented.

[0145] Reference Figure 5 , Figure 5 It is a structural block diagram of an embodiment of a device for acquiring a tension setting value of a cold-rolled steel strip according to the present invention.

[0146] like Figure 5 As shown, the cold-rolled strip tension setting value acquisition device comprises:

[0147] The parameter acquisition module 10 is used to acquire the rolling process parameters of the cold-rolled steel strip;

[0148] A condition setting module 20, for setting an inlet tensile stress condition, an outlet tensile stress condition and a critical value of a ratio of a front slip zone of a roll gap based on the rolling process parameters;

[0149] A ratio calculation module 30, used for calculating the ratio of the front sliding area of ​​the roller gap under the inlet tensile stress condition and the outlet tensile stress condition;

[0150] A critical judgment module 40 is used to judge whether the ratio of the front slip zone of the roll gap reaches a preset critical value of the front slip zone of the roll gap;

[0151] The tension calculation module 50 is used to calculate the inlet tension and the outlet tension respectively according to the inlet tensile stress and the outlet tensile stress output by iterative updating when the ratio of the front slip area of ​​the roll gap reaches a preset critical value of the front slip area of ​​the roll gap.

[0152] The present embodiment provides a device for acquiring the tension setting value of a cold-rolled strip. In the present embodiment, based on the established quantitative relationship between the cold-rolled strip rolling entrance tensile stress, the exit tensile stress and the ratio of the front slip zone of the roll gap, the ratio of the front slip zone of the roll gap is adjusted to a critical value range by continuously iteratively optimizing the entrance tensile stress and the exit tensile stress. The iterative calculation is stable and fast, and can be used for the pre-setting calculation of the cold-rolled strip rolling entrance tension and the exit tension, thereby ensuring that the roll gap does not slip during the rolling process and improving production stability.

[0153] It should be noted that the technical details that are not described in detail in the embodiment of the cold-rolled strip tension setting value acquisition device can be found in the cold-rolled strip tension setting value acquisition method described above provided in any embodiment of the present invention, and will not be repeated here.

[0154] It should be understood that the above is only an example and does not constitute any limitation on the technical solution of the present invention. In specific applications, technicians in this field can make settings as needed, and the present invention does not limit this.

[0155] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of the present invention. In practical applications, technicians in this field can select part or all of them according to actual needs to achieve the purpose of the present embodiment, and no limitation is made here.

[0156] In addition, it should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system 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 system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0157] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0158] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory (ROM) / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0159] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for obtaining a set value of tension of a cold-rolled steel strip, characterized in that: include: Obtain rolling process parameters of cold-rolled strip steel; Based on the rolling process parameters, an inlet tensile stress condition, an outlet tensile stress condition and a critical value of the ratio of the front slip zone of the roll gap are set; Calculating the ratio of the front slip zone of the roller gap under the inlet tensile stress condition and the outlet tensile stress condition; Determining whether the ratio of the front sliding area of ​​the roller gap reaches a preset critical value of the front sliding area of ​​the roller gap; When the ratio of the front slip zone of the roll gap reaches a preset critical value of the front slip zone of the roll gap, the inlet tension and the outlet tension are calculated respectively according to the inlet tensile stress and the outlet tensile stress output by iterative updating.

2. The method according to claim 1, characterized in that The setting of the entrance tensile stress condition, the exit tensile stress condition and the critical value of the ratio of the front slip zone of the roll gap based on the rolling process parameters includes: Obtaining the inlet strip yield strength and the outlet strip yield strength according to the rolling process parameters; Setting the initial value, minimum value and maximum value of the entrance tensile stress according to different preset multiples and the product of the entrance strip yield strength; The initial value, minimum value and maximum value of the inlet tensile stress are used as inlet tensile stress conditions; Setting the initial value, minimum value and maximum value of the outlet tensile stress according to different preset multiples and the product of the outlet strip yield strength; The initial value, minimum value and maximum value of the outlet tensile stress are used as outlet tensile stress conditions; Set the critical value of the roller gap front slip area ratio.

3. The method according to claim 2, characterized in that The initial value of the entrance tensile stress is 0.1 times the entrance strip yield strength, the minimum value is 0.02 times the entrance strip yield strength, and the maximum value is 0.3 times the entrance strip yield strength; the initial value of the exit tensile stress is 0.1 times the exit strip yield strength, the minimum value is 0.02 times the exit strip yield strength, and the maximum value is 0.3 times the exit strip yield strength; the critical value of the roller gap front slip zone ratio ranges from 0.1 to 0.

5.

4. The method according to claim 1, characterized in that The calculating the ratio of the front sliding area of ​​the roller gap under the inlet tensile stress condition and the outlet tensile stress condition comprises: Setting an initial roll profile curve under the inlet tensile stress condition and the outlet tensile stress condition, and determining the inlet position of the rolled piece; Calculate the unit pressure of each section of the rear sliding zone from the entrance to the exit based on the entrance position of the rolled piece; Calculate the unit pressure of each section in the forward sliding zone from the outlet to the inlet; Determine the unit pressure distribution of each section in the roll gap deformation zone according to the unit pressure of each section in the rear sliding zone and the unit pressure of each section in the front sliding zone; Calculating the roll gap thickness distribution according to the unit pressure distribution of each section; Determining whether the roll gap thickness distributions obtained from two adjacent calculations converge; The roll gap thickness distribution is calculated when convergence occurs, otherwise the next round of iterative calculation is performed until the roll gap thickness distribution converges; After the iteration converges, the ratio of the front sliding area of ​​the roll gap is obtained according to the unit pressure distribution of each section and the boundary section between the front sliding area and the rear sliding area.

5. The method according to claim 1, characterized in that The determining whether the ratio of the front sliding area of ​​the roller gap reaches a preset critical value of the front sliding area of ​​the roller gap comprises: Set the precision coefficient; A judgment value is obtained according to the product of the accuracy coefficient and a preset roller gap front sliding area ratio critical value; Calculating the difference between the roller gap front slip zone ratio and the preset roller gap front slip zone ratio critical value; comparing the absolute value of the difference with the judgment value; If the absolute value of the difference is less than or equal to the judgment value, it is determined that the ratio of the front slip area of ​​the roller gap reaches a preset critical value of the front slip area of ​​the roller gap.

6. The method according to claim 1, characterized in that After determining whether the ratio of the front sliding area of ​​the roller gap reaches a preset critical value of the front sliding area of ​​the roller gap, the method further includes: When the ratio of the front sliding area of ​​the roller gap does not reach a preset critical value of the front sliding area of ​​the roller gap, judging whether the current outlet tensile stress reaches the maximum value of the outlet tensile stress; If the current outlet tensile stress does not reach the maximum outlet tensile stress value, the current outlet tensile stress is updated by using the secant method, and the step of calculating the ratio of the front slip zone of the roll gap under the conditions of the inlet tensile stress and the outlet tensile stress is returned to until the ratio of the front slip zone of the roll gap reaches a preset critical value of the ratio of the front slip zone of the roll gap; If the current outlet tensile stress reaches the maximum value of the outlet tensile stress, the current outlet tensile stress is set as the maximum value of the outlet tensile stress, and the inlet tensile stress is updated by the secant method, and the step of calculating the ratio of the front slip area of ​​the roller gap under the inlet tensile stress condition and the outlet tensile stress condition is returned to until the ratio of the front slip area of ​​the roller gap reaches the preset critical value of the front slip area of ​​the roller gap.

7. The method according to claim 6, characterized in that The method of updating the current outlet tensile stress by using the secant method includes: Setting proportional relationships based on the secant method; Get the outlet tensile stress increment after iterative calculation; The current outlet tensile stress is iteratively updated according to the outlet tensile stress increment and the proportional relationship to obtain a revised outlet tensile stress.

8. The method according to any one of claims 1 to 7, characterized in that The rolling process parameters include the inlet thickness of the strip, the outlet thickness of the strip, the width of the strip, the inlet yield strength of the strip, the outlet yield strength of the strip, the diameter of the working rolls and the friction coefficient of the roll gap.

9. A device for obtaining a set value of tension of a cold-rolled steel strip, characterized in that: include: A parameter acquisition module is used to obtain rolling process parameters of cold-rolled strip steel; A condition setting module, used to set an inlet tensile stress condition, an outlet tensile stress condition and a critical value of the ratio of the front slip zone of the roll gap based on the rolling process parameters; A ratio calculation module, used for calculating the ratio of the front sliding area of ​​the roller gap under the inlet tensile stress condition and the outlet tensile stress condition; A critical judgment module is used to judge whether the ratio of the front slip zone of the roll gap reaches a preset critical value of the front slip zone of the roll gap; The tension calculation module is used to calculate the inlet tension and the outlet tension respectively according to the inlet tensile stress and the outlet tensile stress output by iterative update when the ratio of the front slip area of ​​the roller gap reaches a preset critical value of the front slip area of ​​the roller gap.

10. An electronic device, characterized in that: The electronic device comprises: a memory, a processor and a cold-rolled strip tension setting value acquisition program stored in the memory and executable on the processor, wherein the cold-rolled strip tension setting value acquisition program is configured to implement a cold-rolled strip tension setting value acquisition method as described in any one of claims 1 to 8.

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