A micro-tension load distribution method and device for a continuous rolling mill

Abstract

The present application relates to a kind of micro-tension load distribution methods for continuous rolling mill group, the continuous rolling mill group includes several racks, including the following steps: the moment of force of the each rack is obtained, reduction ratio and roll diameter;According to the free load torque of the first end rack, the moment of force of the each rack, the reduction ratio of the each rack and the roll diameter of the each rack, the free load torque of the each rack except the first end rack is calculated;According to the free load torque of the each rack and the torque arm length of the each rack, the rolling load of the each rack is calculated;Based on free rolling torque, accurate and reasonable rolling load distribution is carried out, which ensures the stable tension rolling between the racks of continuous rolling mill group, effectively avoids the phenomenon of material stack pulling between the racks, thereby effectively improves the quality of product, and reduces the dependence on operator's technology.

Description

Technical Field

[0001] This invention relates to the field of continuous rolling mill technology, and more specifically to a micro-tension load distribution method and device for continuous rolling mills. Background Technology

[0002] Tension control is a technology for automatically controlling the tension on a workpiece that is either in continuous motion or stationary between two processing machines. Tension control is mainly applied in roughing and intermediate rolling mills. For hot strip rolling lines, the main issues can be summarized as follows:

[0003] From an application perspective, most methods employ head tension control, which can be described as a method that uses the head changes of free load rolling torque and non-free load rolling torque to calculate the changes in inter-stand tension and provide the upstream stand speed adjustment amount. Head tension control, to some extent, hinders the changes in inter-stand tension.

[0004] If the rolling load and speed regime are properly allocated, tension control adjustment is beneficial to the system. However, if the allocation is unreasonable, tension control adjustment will have the opposite effect. Therefore, the method of adjusting the speed simply by changing the tension has drawbacks, because it calculates the increment of the tension between the stands, not the tension between the stands.

[0005] Currently, in continuous rolling production, unreasonable distribution of rolling load often leads to material accumulation and pulling, affecting product quality. Therefore, the distribution of rolling load in continuous rolling mills is particularly important. Summary of the Invention

[0006] The purpose of this invention is to provide a micro-tension load distribution method and device for continuous rolling mills, aiming to solve the problem of low accuracy and rationality of rolling load distribution in the prior art, which leads to easy material accumulation and pulling.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] One approach provides a method for distributing micro-tension loads in a continuous rolling mill, the mill comprising several stands, and includes the following steps:

[0009] Obtain the resultant torque, reduction ratio, and roll diameter for each frame;

[0010] The free load torque of each frame other than the first frame is calculated based on the free load torque of the first frame, the resultant torque of each frame, the reduction ratio of each frame, and the roll diameter of each frame.

[0011] The rolling load of each stand is calculated based on the free load torque of each stand and the torque arm length of each stand.

[0012] More preferably, the resultant torque of each rack includes:

[0013] The sum of the free load torque of the frame and the tension torque of the frame;

[0014] The tension moment of the rack includes upstream tension moment and downstream tension moment, wherein the upstream tension moment is the tension moment generated by the tension between the two racks on the upstream rack, and the downstream tension moment is the tension moment generated by the tension between the two racks on the downstream rack.

[0015] More preferably, the resultant torque of each frame further includes:

[0016] The resultant torque of the first end frame is the sum of the free load torque of the first end frame and the upstream tension torque of the first end frame;

[0017] The resultant torque of the tail end frame is the sum of the free load torque of the tail end frame and the downstream tension torque of the tail end frame.

[0018] The resultant torque of each remaining frame, excluding the first and last frames, is the sum of the free load torque of each remaining frame minus the upstream tension torque of each remaining frame and the downstream tension torque of each remaining frame.

[0019] More preferably, the tension torque includes:

[0020] The tension between the two frames is multiplied by the diameter of the rolls of the frame and then divided by twice the reduction ratio of the frame.

[0021] More preferably, the calculation expression for the free load torque of each frame is shown in equation (1):

[0022]

[0023] Where i is a natural number greater than 1, m is a natural number satisfying 1 ≤ m ≤ i - 1; M 0i M represents the free load torque of the i-th frame; Σi This represents the resultant torque of the i-th frame;

[0024] In equation (1), a i The calculation expression is shown in equation (2):

[0025]

[0026] Among them, i iD represents the reduction ratio of the i-th frame; i This represents the diameter of the rolls in the i-th frame.

[0027] More preferably, the rolling load calculation expression for each stand is shown in equation (3):

[0028]

[0029] Where, r i This represents the torque arm length of the i-th frame.

[0030] More preferably, the expression for calculating the tension between the two frames is shown in equation (4):

[0031] f i(i+1) =f (i-1)i +a i (M Σi -M 0i ) = a i+1 (M Σ(i+1) -M 0(i+1) (4)

[0032] Among them, f i(i+1) This represents the tension between the i-th rack and the (i+1)-th rack.

[0033] More preferably, the method further includes:

[0034] Based on the minimum tension between the stands, the rolling load is distributed to the stands, and the expression for the rolling load distribution relationship of the stands is shown in equation (5):

[0035] f(b1, ..., b) i )=0 (5)

[0036] More preferably, the method further includes:

[0037] According to the inter-frame tension f i(i+1) Obtain the small tension f' between the frames i(i+1) Small tension range (β) <f’ i(i+1) <γ);

[0038] When the mill stands deviate from a steady state during rolling, the rolling load distribution of the mill stands is corrected within the small tension range.

[0039] According to the small tension range (β) <f' i(i+1) <γ) to obtain the small tension f' i(i+1) The margin range of steady-state changes;

[0040] When the tension between the racks changes in a trend, the load distribution of the racks is corrected within the range of the change margin.

[0041] The small tension f' is controlled based on the aforementioned variation margin range. i(i+1) Hysteresis interval;

[0042] When the small tension f' is increased i(i+1) During steady-state changes, the range of the hysteresis interval is reduced, and the small tension f' is slowed down. i(i+1) When the steady-state change occurs, the range of the hysteresis interval is increased.

[0043] On the other hand, a micro-tension load distribution system for a continuous rolling mill is provided, the load distribution system including at least one processor; and a memory storing instructions that, when executed by the at least one processor, implement the steps of the method described above.

[0044] The beneficial effects of this invention are that, based on the free rolling torque, the rolling load is accurately and reasonably distributed, ensuring stable tension rolling between the stands of the continuous rolling mill, effectively avoiding the phenomenon of material piling up between stands, thereby effectively improving product quality and reducing reliance on operator skills. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the load distribution system in this invention;

[0046] Figure 2 This is a schematic diagram of load distribution in this invention;

[0047] Figure 3 This is a schematic diagram of the load distribution steps in this invention;

[0048] Figure 4 This is a schematic diagram of the structure of a continuous rolling mill in the prior art of this invention. Detailed Implementation

[0049] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings and embodiments.

[0050] In the current technology, a schematic diagram of the operation of a continuous rolling mill is shown below. Figure 4As shown, the continuous rolling mill operates from left to right. Its main working principle is to roll raw materials of a certain length, width, and thickness into products of a certain length, width, and thickness by utilizing the equal flow rate of billets passing through the mills per second. Assuming the billet passing through F1 has a thickness of H1, a width of W1, and a speed of V1, the billet passing through F2 has a thickness of H2, a width of W2, and a speed of V2, and the billet passing through F3 has a thickness of H3, a width of W3, and a speed of V3, then the amount of material passing through mills F1, F2, and F3 per unit time is equal, meaning the flow rate per second is equal. This leads to the formula: W1*H1*V1=W2*H2*V2=W3*H3*V3. Using this theoretical basis, the load, roll gap, and speed of each mill can be determined based on the incoming material specifications, target specifications, and the number of mills.

[0051] Some embodiments of the present invention relate to a micro-tension load distribution system for continuous rolling mills, such as Figure 1 As shown, the load distribution system 1 includes at least one processor 2; and a memory 3 storing instructions that, when executed by at least one processor 2, are used to implement all the steps in the following method implementation.

[0052] Some embodiments of the present invention also relate to a method for distributing micro-tension loads in a continuous rolling mill, the continuous rolling mill comprising a plurality of stands, comprising the following steps:

[0053] Obtain the resultant torque, reduction ratio, and roll diameter for each frame;

[0054] The free load torque of each frame other than the first frame is calculated based on the free load torque of the first frame, the resultant torque of each frame, the reduction ratio of each frame, and the roll diameter of each frame.

[0055] The rolling load of each stand is calculated based on the free load torque of each stand and the torque arm length of each stand.

[0056] Normally, the load is evenly distributed or weighted according to the design and process requirements of the rolling equipment.

[0057] 1. Uniform Distribution: Distribute the remaining rolling load evenly across each stand. If there are n remaining stands, the load on each stand is the rolling load divided by the number of remaining stands.

[0058] 2. Weighting: Different weights are assigned to each rack based on its capacity and load-bearing capacity. Stronger racks bear more load, while weaker racks bear less load. Weights can be set according to actual needs.

[0059] There are generally two methods for verifying assignment relationships:

[0060] 1. Theoretical Calculation: Based on the load distribution relationship and the load-bearing capacity of the racks, the load borne by each rack can be theoretically calculated. The load of each rack can be calculated using load distribution formulas based on given loads and weights.

[0061] 2. Actual Measurement Verification: The load distribution relationship is verified by measuring the load on each rack during actual production. Sensors or pressure measuring instruments can be used to obtain load data for each rack, and the results are compared with theoretical calculations.

[0062] The above methods can be used to derive and verify the rolling load of the remaining stands, ensuring the rationality and accuracy of load allocation. It should be noted that the actual load allocation method may vary depending on specific circumstances and needs to be adjusted and optimized based on actual requirements and equipment parameters.

[0063] In some embodiments of the micro-tension load distribution method for continuous rolling mills, the resultant torque of each stand includes:

[0064] The sum of the free load torque of the frame and the tension torque of the frame;

[0065] The tension moment of the rack includes upstream tension moment and downstream tension moment, wherein the upstream tension moment is the tension moment generated by the tension between the two racks on the upstream rack, and the downstream tension moment is the tension moment generated by the tension between the two racks on the downstream rack.

[0066] In a continuous rolling mill, the load distribution of each stand is usually determined based on the principle of balancing working rolling forces.

[0067] In a continuous rolling mill, each stand bears a portion of the rolling force, which is transmitted from the upstream stand to the downstream stand. The goal of stand load distribution is to ensure that each stand bears a relatively balanced rolling force, thereby achieving continuous rolling of the material.

[0068] Specifically, the load distribution relationship of each rack can be determined by the following principle:

[0069] 1. Rolling Force Balance: In a continuous rolling mill, the rolling force transmitted from the upstream stand to the downstream stand should be equal to the rolling force of the downstream stand. This can be achieved by using a transfer device (such as a roller conveyor) between the stands.

[0070] 2. Torque balance: Free load torque M of each frame 0i With rolling load b i There is a certain relationship between them. Ideally, the free load torque of each rack should be zero.

[0071] In summary, the load distribution relationship of each stand in a continuous rolling mill can be expressed as a combination of a force balance equation and a moment balance equation, where the force balance equation ensures the balance of rolling forces and the moment balance equation ensures the balance of free load torques.

[0072] The specific load distribution formula can be determined based on the specific frame structure and operating parameters. Generally, factors such as the rigidity of the frame, the elasticity of the roller conveyor, and the deformation of the rolled piece need to be considered.

[0073] In some embodiments of the micro-tension load distribution method for continuous rolling mills, the resultant torque of each stand further includes:

[0074] The resultant torque of the first end frame is the sum of the free load torque of the first end frame and the upstream tension torque of the first end frame;

[0075] The resultant torque of the tail end frame is the sum of the free load torque of the tail end frame and the downstream tension torque of the tail end frame.

[0076] The resultant torque of each remaining frame, excluding the first and last frames, is the sum of the free load torque of each remaining frame minus the upstream tension torque of each remaining frame and the downstream tension torque of each remaining frame.

[0077] In some embodiments of the micro-tension load distribution method for continuous rolling mills, the tension torque includes:

[0078] The tension between the two frames is multiplied by the diameter of the rolls of the frame and then divided by twice the reduction ratio of the frame.

[0079] In some implementations of the micro-tension load distribution method for continuous rolling mills, the calculation expression for the free load torque of each stand is shown in equation (1):

[0080]

[0081] Where i is a natural number greater than 1, m is a natural number satisfying 1 ≤ m ≤ i - 1; M 0i M represents the free load torque of the i-th frame; Σi This represents the resultant torque of the i-th frame;

[0082] In equation (1), a i The calculation expression is shown in equation (2):

[0083]

[0084] Among them, i i D represents the reduction ratio of the i-th frame; i This represents the diameter of the rolls in the i-th frame.

[0085] In some implementations of the micro-tension load distribution method for continuous rolling mills, the calculation expression for the rolling load of each stand is shown in equation (3):

[0086]

[0087] Where, r i This represents the torque arm length of the i-th frame.

[0088] In some implementations of the micro-tension load distribution method for continuous rolling mills, the tension calculation expression between the two stands is shown in equation (4):

[0089] f i(i+1) =f (i-1)i +a i (M Σi -M 0i ) = a i+1 (M Σ(i+1) -M 0(i+1) (4)

[0090] Among them, f i(i+1) This represents the tension between the i-th rack and the (i+1)-th rack.

[0091] In some implementations of the micro-tension load distribution method for continuous rolling mills, the method further includes:

[0092] Based on the minimum tension between the stands, the rolling load is distributed to the stands, and the expression for the rolling load distribution relationship of the stands is shown in equation (5):

[0093] f(b1, ..., b) i )=0 (5)

[0094] In some implementations of the micro-tension load distribution method for continuous rolling mills, the method further includes:

[0095] According to the inter-frame tension f i(i+1) Obtain the small tension f' between the frames i(i+1) Small tension range (β) <f’ i(i+1) <γ);

[0096] When the mill stands deviate from a steady state during rolling, the rolling load distribution of the mill stands is corrected within the small tension range.

[0097] According to the small tension range (β) <f' i(i+1) <γ) to obtain the small tension f' i(i+1) The margin range of steady-state changes;

[0098] When the tension between the racks changes in a trend, the load distribution of the racks is corrected within the range of the change margin.

[0099] The small tension f' is controlled based on the aforementioned variation margin range. i(i+1) Hysteresis interval;

[0100] When the small tension f' is increased i(i+1) During steady-state changes, the range of the hysteresis interval is reduced, and the small tension f' is slowed down. i(i+1) When the steady-state change occurs, the range of the hysteresis interval is increased.

[0101] In some implementation methods for micro-tension load distribution in continuous rolling mills, the calculation principles for free rolling torque and inter-stand tension are as follows:

[0102] The effects of inter-rack tension on the upstream and downstream racks are opposite. Taking the upstream rack as the reference, the effect on the upstream rack is defined as a positive action (+), while the effect on the downstream rack is a negative action (-).

[0103] Let M Σi M is the sum of the torques of the i-th frame, which is the actual torque of the motor. i f is the free load moment of the i-th frame. i(i+1) For the tension between the i-th rack and the (i+1)-th rack, based on the relationship between the incremental tension torque and the tension between racks...

[0104]

[0105] In the case of a model, different numbers of continuous rolling mill stands can be considered separately. The tension torque generated by the tension between the upstream and downstream stands varies with the roll diameter and reduction ratio. That is, for different stands, the tension and tension torque are the same, but the tension torque is different. Therefore, it is more reasonable to express the tension torque in the equation system as an expression for the tension.

[0106] The calculation of free load torque is based on the free torque of the sampling stand (first stand). The following is the calculation of free rolling load torque, which is explained in four cases:

[0107] M 01 This is the measured value of the free load torque of the first stand before continuous rolling.

[0108] Case with 2 racks:

[0109]

[0110] In the formula, ΔM1 and ΔM2 represent the tension torques generated between the frames on the front and rear frames, where...

[0111]

[0112] Transforming the above equation yields f 12 =a1(M Σ1 -M 01 )=a2(M Σ2 -M 02 ), where defined

[0113] Thus, the free load torque M of the second frame can be obtained. 02

[0114]

[0115] After obtaining the free load torque of the second stand, the change in tension between the stands can be calculated based on the real-time change in rolling torque.

[0116] Case with 3 racks:

[0117] For the three-rack configuration, the following relationship holds:

[0118]

[0119] Calculation yields:

[0120] f 23 =f 12 +a2(M Σ2 -M 02 )=a1(M Σ1 -M 01 )+a2(M Σ2 -M 02 )

[0121] =a3(M Σ3 -M 03 )

[0122] The free load torque of the third frame can be obtained:

[0123]

[0124] Case with 4 racks:

[0125]

[0126] The calculation yields:

[0127] f 34 =f 23 +a3(M Σ3 -M 03 )=a4(M Σ4 -M 04 )

[0128] The free load torque of the fourth frame can be obtained:

[0129]

[0130] Similarly, we can calculate:

[0131]

[0132] In some implementations of the micro-tension load distribution method for continuous rolling mills, the correction of the process model load distribution is as follows:

[0133] Given the existence of a model, under the condition of free rolling on the first stand, the free rolling load torque of the remaining continuous rolling stands can be calculated by sampling the stands. Based on the load distribution relationship of each stand, the model rolling load of the remaining stands can be derived and verified, and the correction of the model rolling load can be given online to achieve the optimal load distribution relationship.

[0134] After the load is adjusted, the rolling load of a stand that forms a continuous rolling pattern with the upstream stand will change. After forming a continuous rolling pattern with the downstream stand, the rolling load will also change to reflect the tension relationship under different continuous rolling conditions.

[0135] A certain rolling load relationship corresponds to a defined tension between stands. If the minimum tension (zero tension) is used as the benchmark (cost function) for the load distribution of the rolling mill, the stacking tension relationship between stands will be minimized, resulting in excellent load distribution and minimal speed adjustment.

[0136] The expression for the tension between each frame is calculated by solving the system of equations. Under the condition of minimum tension, i.e., f i(i+1) =0

[0137] That is, the load distribution relationship under pressure satisfies f(b1, ..., b) i )=0 condition.

[0138] In some implementations of the micro-tension load distribution method for continuous rolling mills, the process control strategy is as follows:

[0139] Tension control is guided by two principles: the principle of minimum tension and the principle of stable rolling. Minimum tension implies the uniformity and optimality of the rolling load. If the principle of minimum tension is met, stable rolling will inevitably occur. Stable rolling indicates that the stacking relationship between the stands is appropriate, that is, the exit speed equals the inlet speed, which means the tension is zero. This indicates that stable rolling must be minimum tension rolling.

[0140] Of course, the rolling process is affected by many factors and is not static. The entire rolling process is a continuous transition from one steady-state range to another. If this transition cannot be completed, the rolling will become unstable rolling. When it leaves the stable tension range of rolling, it will cause serious steel piling or steel pulling, which will seriously affect the width and thickness of the product and may even cause scrap steel.

[0141] The purpose of tension control is to find a stable tension range for rolling. When rolling deviates from a stable state, the control quantity can promptly pull the tension between stands back into the stable tension range. This control approach avoids real-time adjustments while ensuring speed.

[0142] The prerequisite for tension control is the accurate judgment of the tension change trend between stands. When the tension does indeed change in a trend, the allowable margin for tension change is found, and the control quantity is given in a step-like manner according to this range to achieve the purpose of minimum tension rolling.

[0143] Setting a redundancy range for low-tension control can be called a hysteresis range. This range is set according to actual adjustment needs, indicating transitions in the direction of tension increase and decrease. If the steady-state change needs to be accelerated, the hysteresis range should be reduced; conversely, it should be increased. The main purpose of setting a hysteresis range is to improve control stability, which is beneficial for the stability of trend-based adjustments.

[0144] In some implementation methods for micro-tension load distribution in continuous rolling mills, the intelligent analysis of data is as follows:

[0145] The intelligent module for process control mainly accomplishes the following two tasks: first, establishing an expert experience database; and second, establishing a big data-driven model.

[0146] The expert experience integrates mature and effective field experience to form a library model system under different conditions. It integrates highly coupled relevant data, triggers corresponding solutions under different problem conditions, and provides a useful supplement to the process control system.

[0147] Big data-driven models provide reference corrections for the established models through the analysis of related data. The big data model adopts an online multiple linear regression algorithm, which effectively solves the model specification error and improves the model accuracy.

[0148] The embodiments and functional operations of the subject matter described in this specification can be implemented in the following ways: digital electronic circuits, tangibly implemented computer software or firmware, computer hardware, including the structures disclosed in this specification and their equivalents, or combinations thereof. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs, that is, one or more modules of computer program instructions encoded on one or more tangible non-transitory program carriers, for execution by a data processing device or to control the operation of the data processing device.

[0149] Alternatively or additionally, program instructions may be encoded on artificially generated propagation signals, such as machine-generated electrical, optical, or electromagnetic signals, which are then generated as coded information to be transmitted to an appropriate receiver device executed by data processing equipment. The computer storage medium may be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or one or more combinations of the above.

[0150] The term "data processing device" encompasses all kinds of devices, apparatuses, and machines used for processing data, including, for example, programmable processors, computers, or multiprocessor systems or multicomputer systems. Devices may include special-purpose logic circuitry, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits). In addition to hardware, devices may also include code that creates the execution environment for associated computer programs, such as processor firmware, protocol stacks, database management systems, operating systems, or combinations thereof.

Claims

1. A method for distributing micro-tension load in a continuous rolling mill, the continuous rolling mill comprising a plurality of stands, characterized in that, Includes the following steps: Obtain the resultant torque, reduction ratio, and roll diameter for each frame; The free load torque of each frame other than the first frame is calculated based on the free load torque of the first frame, the resultant torque of each frame, the reduction ratio of each frame, and the roll diameter of each frame. The rolling load of each stand is calculated based on the free load torque of each stand and the torque arm length of each stand; The free load torque of each frame is calculated as shown in equation (1): （1） in, For natural numbers greater than 1, are natural numbers and satisfy ; Indicates the first The free load torque of the frame; Indicates the first The resultant torque of the frame; In equation (1), The calculation expression is shown in equation (2): （2） in, Indicates the first The reduction ratio of the frame; Indicates the first The diameter of the rolls in the machine frame; The calculation expression for the rolling load of each stand is shown in equation (3): （3） in, Indicates the first The length of the torque arm of the frame; The expression for calculating the tension between the two frames is shown in equation (4): （4） in, Indicates the first rack and the Tension between frames; Based on the minimum tension between the stands, the rolling load is distributed to the stands, and the expression for the rolling load distribution relationship of the stands is shown in equation (5): （5） According to the inter-rack tension Obtain small tension between racks small tension range ; When the mill stands deviate from a steady state during rolling, the rolling load distribution of the mill stands is corrected within the small tension range. According to the aforementioned small tension range The small tension is obtained The margin range of steady-state changes; When the tension between the racks changes in a trend, the load distribution of the racks is corrected within the range of the change margin. The small tension is controlled based on the aforementioned variation margin range. Hysteresis interval; When the small tension is increased During steady-state changes, the range of the hysteresis interval is reduced, and the small tension is slowed down. When the steady-state change occurs, the range of the hysteresis interval is increased.

2. The method for micro-tension load distribution in a continuous rolling mill according to claim 1, characterized in that, The resultant torque of each rack includes: The sum of the free load torque of the frame and the tension torque of the frame; The tension moment of the rack includes upstream tension moment and downstream tension moment, wherein the upstream tension moment is the tension moment generated by the tension between two racks on the upstream rack, and the downstream tension moment is the tension moment generated by the tension between two racks on the downstream rack.

3. The method for micro-tension load distribution in a continuous rolling mill according to claim 2, characterized in that, The resultant torque of each rack also includes: The resultant torque of the first end frame is the sum of the free load torque of the first end frame and the upstream tension torque of the first end frame; The resultant torque of the tail end frame is the sum of the free load torque of the tail end frame and the downstream tension torque of the tail end frame; The resultant torque of each remaining frame, excluding the first and last frames, is the sum of the free load torque of each remaining frame minus the upstream tension torque of each remaining frame and the downstream tension torque of each remaining frame.

4. The method for micro-tension load distribution in a continuous rolling mill according to claim 3, characterized in that, The tension torque includes: The tension between the two frames is multiplied by the diameter of the rolls of the frame and then divided by twice the reduction ratio of the frame.

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