A method for predicting and controlling inner ring edge wave formation in a strip steel cold coiling process

Abstract

The present application relates to a kind of inner circle edge wave formation prediction and control method in strip steel cold coiling process, the method includes the following steps: step (1) coiler set tool parameters collection, step (2) strip and coiling process parameter collection, step (3) circumferential and radial stress calculation in coiling process, step (4) circumferential and radial stress calculation in drum removal process, step (5) strip inner circle malignant edge wave formation critical stress experimental verification, step (6) new coiling process and tool parameters, step (7) circumferential and radial stress calculation in coiling process, step (8) circumferential and radial stress calculation in drum removal process, step (9) stress and malignant edge wave critical stress comparison under new coiling condition, step (10) whether new coiling process leads to collapse, if so, feedback step (6), if not, control ends.The technical scheme provides guidance for the actual control and solution of strip steel inner circle coiling problem.

Description

TECHNICAL FIELD

[0001] The present application relates to a control method, in particular to a kind of inner circle edge wave formation prediction and control method in strip steel cold coiling process, belong to steel processing technical field. BACKGROUND

[0002] Steel material is the most widely used metal structural material at present, and plate is one of the most important forms of steel material application. Plate processing generally involves multiple passes of hot rolling, cold rolling and multiple intermediate annealing processes. In order to facilitate production and transportation, coiling is also involved in the processing of thin plates. Plate shape is one of the important indicators for evaluating plate quality. There have been a lot of basic and applied research on plate shape control during rolling, annealing and other processes. During coiling process, thin plate or strip is gradually wound on the reel under the action of certain tension, forming a certain coil weight (coiling number) of steel coil. During coiling process, as the number of coiling layers gradually increases, the circumferential stress of the inner circle strip (near the reel part) gradually changes from tensile stress to compressive stress. Along the width direction of the strip, the thickness, microstructure distribution and residual stress often show certain unevenness, such as the thickness of the strip often shows positive crown distribution, i.e. the thickness of the center part of the strip is thicker, and the thickness of the edge part is smaller. Therefore, due to the uneven thickness, superposition of residual stress and other factors, the circumferential compressive stress of the center part of the inner circle strip during coiling process may be significantly higher than the nominal compressive stress, exceeding its compressive yield strength, and then a certain compression deformation (circumferential shrinkage) occurs, while the stress on the edge part of the strip is smaller and no plastic deformation occurs, thus leading to the problem of uneven deformation during coiling process and the formation of edge wave phenomenon after uncoiling. At present, there is no good prediction and control method for the problem of inner circle edge wave during coiling process. Therefore, there is an urgent need for a new scheme to solve the above technical problems. SUMMARY

[0003] The present application is just for the problems existing in the prior art, and provides a kind of inner circle edge wave formation prediction and control method in strip steel cold coiling process, which provides guidance for the actual control and solution of strip steel inner circle coiling problem.

[0004] In order to achieve the above purpose, the technical scheme of the present application is as follows: a kind of inner circle edge wave formation prediction and control method in strip steel cold coiling process, characterized in that the method comprises the following steps:

[0005] Step (1) collecting coiling unit work die parameters,

[0006] Step (2) collecting strip and coiling process parameters,

[0007] Step (3) calculating circumferential and radial stress during coiling process,

[0008] Step (4) calculation of circumferential and radial stress during drum removal,

[0009] Step (5) experimental verification of the critical stress of the malignant edge wave in the inner coil of the strip,

[0010] Step (6) new coiling process and die parameters,

[0011] Step (7) calculation of circumferential and radial stress during coiling,

[0012] Step (8) calculation of circumferential and radial stress during drum removal,

[0013] Step (9) comparison of stress and critical stress of malignant edge wave under the new coiling condition,

[0014] Step (10) whether the new coiling process leads to collapse, if so, feedback step (6), if not, the control ends.

[0015] As an improvement of the present application, step (1) coiling unit die parameter collection, specifically as follows: for the strip coiling unit that has serious inner coil coiling failure (edge wave) problem, collect the inner and outer diameter of the strip drum and other die parameters; step (2) strip and coiling process parameter collection, for the strip coiling unit that has serious inner coil coiling failure (edge wave) problem, collect the strip thickness, coiling tension, and coiling layer (roll weight) parameters, to provide necessary data for stress distribution calculation in the coiling process.

[0016] As an improvement of the present application, step (3) calculation of circumferential and radial stress during coiling, specifically as follows:

[0017] 1) According to the relationship between the internal pressure and circumferential stress of thin-walled shell barrels, the relationship between the coiling tension, the thickness of the strip and the internal pressure stress of the strip, i.e. the radial stress during single-layer coiling process, is:

[0018]

[0019] Where σ T is the coiling tension of the strip, P is the radial pressure stress of the plate under the action of the coiling tension, r is the radius of the barrel, and t is the thickness of the strip;

[0020] 2) According to the theory of axisymmetric mechanical distribution:

[0021]

[0022]

[0023] σ rθ = 0

[0024] Where σθ is the circumferential (tangential stress) ; σ r is the radial stress; σ rθ is the shear stress; A and C are constants, which are mainly determined according to boundary conditions;

[0025] 3) assuming that the winding drum is a rigid object, and its inner radius is a m , the outer radius of the steel coil is b, p0 is the internal pressure stress when a layer is wound, and the radial and circumferential stresses satisfy:

[0026]

[0027]

[0028] 4) the forming process of the steel coil is a process of continuously increasing one coil after another, and then the stress distribution after winding can be calculated by cyclic iteration method according to all the equations of 1) - 3), including the circumferential stress and radial stress distribution.

[0029] As an improvement of the present application, step (4) calculation of circumferential and radial stresses during the removal of the winding drum: under the existing working conditions, the stress calculation during the removal of the winding drum can be considered to satisfy the following conditions: a normal stress is applied at the inner diameter of the steel coil, and its absolute value is exactly equal to the radial compressive stress at the inner diameter of the steel coil after winding is completed, while the radial stress at the outer diameter of the steel coil is zero (after winding is completed, the outer side of the steel coil is in a radial free state), and thus the stress distribution after the removal of the winding drum can be calculated;

[0030] Step (5) experimental verification of the formation of critical stress of the malignant edge wave of the inner coil of the strip: the malignant edge wave refers to the situation that the amplitude, period, etc. of the edge wave cannot meet the customer's requirements. According to the actual unwinding situation, the length of the inner coil of the strip with malignant edge wave under the existing winding working conditions is recorded, and the circumferential stress corresponding to the length of the malignant edge wave is recorded as σk according to the calculation of the stress distribution after the removal of the winding drum;

[0031] Step (6) new winding process and tool parameters: for the same specification of the strip, the winding tension, the size of the winding drum, the number of layers (coil weight), etc. are adjusted to form a set of new winding process and tool parameters.

[0032] As an improvement of the present application, step (7) calculation of circumferential and radial stresses during winding: according to the calculation method in step (3) and the new winding process and tool parameters in step (6), the winding tension distribution is recalculated;

[0033] Step (8) calculation of circumferential and radial stresses during the removal of the winding drum: based on the stress distribution during winding calculated in step (7), the stress distribution after the removal of the winding drum under the new winding process and tool parameters is calculated according to the calculation method in step (4).

[0034] As an improvement of the present application, the comparison between the stress under the new coiling condition of step (9) and the critical stress of the malignant edge wave: compare the stress obtained in step (8) with σk obtained in step (5), if the circumferential stress of the innermost coil under the new coiling process condition ≤ σk (absolute value comparison), it means that the new adjusted coiling process can obtain a steel coil without malignant edge wave, at this time the parameters formed in step (6) are the new coiling process and die parameters without malignant edge wave of the inner coil of the strip; if the circumferential stress of the innermost coil under the new coiling process condition > σk (absolute value comparison), it means that the coiling tension, coiling drum size, number of layers (coil weight) and other parameters need to be further adjusted, and the process starts again from step (6).

[0035] As an improvement of the present application, whether the new coiling process of step (10) leads to collapse, which is as follows:

[0036] If the "new coiling process and die parameters without malignant edge wave of the inner coil of the strip" are determined in step (9), the actual coiling is further carried out according to the die and process parameters, and it is observed whether the collapse phenomenon occurs, if not, the process parameters determined in step (9) are the new coiling process and die parameters balanced between the edge wave of the inner coil of the strip and the complete steel coil, and the prediction and control of the edge wave of the inner coil of the strip in the cold coiling process of the strip is ended; if the collapse occurs, the die and coiling process parameters need to be adjusted again, that is, back to step (6).

[0037] Compared with the prior art, the present application has the following advantages: the technical scheme can effectively guide the process adjustment and coiling drum size selection in the coiling site, thereby realizing effective control of the inner coil coiling defect in the cold coiling process of the strip, greatly reducing the material loss and return due to the inner coil coiling defect, and significantly reducing the processing and preparation cost of the strip. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The process flow chart for the prediction and control method of the edge wave of the inner coil of the strip in the coiling process of the steel strip is shown in the figure;

[0039] Figure 2 The simplified schematic diagram of the coiling process of the strip is shown in the figure;

[0040] Figure 3 The stress distribution diagram of the stress with the thickness of the steel coil (the distance from the center of the steel coil) is shown in the figure;

[0041] Figure 4 The key stress diagram of the formation of the malignant edge wave of the inner coil of the strip is shown in the figure;

[0042] Figure 5 The circumferential stress comparison diagram before and after the adjustment of the coiling tension is shown in the figure. DETAILED DESCRIPTION

[0043] In order to deepen the understanding of the present application, the following detailed description of the present embodiment is made in conjunction with the accompanying drawings.

[0044] Example 1: see Figure 1 — Figure 5 A method for predicting and controlling the formation of edge waves in the inner circle of a strip steel cold coiling process, the method comprising the following steps:

[0045] Step (1) collecting work die parameters of the coiler set, specifically as follows: for the strip coiler set where serious inner circle coiling failure (edge wave) problems occur, collecting work die parameters such as the inner and outer diameters of the strip coil;

[0046] Step (2) collecting strip and coiling process parameters, specifically as follows: for the strip coiler set where serious inner circle coiling failure (edge wave) problems occur, collecting parameters such as the thickness of the strip, the coiling tension, and the number of layers (coil weight) to provide necessary data for stress distribution calculation in the coiling process.

[0047] Step (3) calculating the circumferential and radial stresses in the coiling process, specifically as follows:

[0048] Step (4) calculating the circumferential and radial stresses in the process of removing the coil, specifically as follows:

[0049] Step (5) experimental verification of the critical stress of the formation of serious edge waves in the inner circle of the strip, specifically as follows:

[0050] Step (6) new coiling process and work die parameters, specifically as follows:

[0051] Step (7) calculating the circumferential and radial stresses in the coiling process, specifically as follows:

[0052] Step (8) calculating the circumferential and radial stresses in the process of removing the coil, specifically as follows:

[0053] Step (9) comparing the stresses under the new coiling condition with the critical stress of serious edge waves, specifically as follows:

[0054] Step (10) determining whether the new coiling process leads to coil collapse, if so, returning to step (6), if not, the control ends.

[0055] Step (1) collecting work die parameters of the coiler set, specifically as follows: for the strip coiler set where serious inner circle coiling failure (edge wave) problems occur, collecting work die parameters such as the inner and outer diameters of the strip coil;

[0056] Step (2) collecting strip and coiling process parameters, specifically as follows: for the strip coiler set where serious inner circle coiling failure (edge wave) problems occur, collecting parameters such as the thickness of the strip, the coiling tension, and the number of layers (coil weight) to provide necessary data for stress distribution calculation in the coiling process.

[0057] Step (3) calculating the circumferential and radial stresses in the coiling process, specifically as follows:

[0058] 1) According to the relationship between the internal pressure and the circumferential stress of a thin-walled shell type barrel, the relationship between the coiling tension and the thickness of the strip and the internal compressive stress of the strip, i.e. the radial stress in the single-layer coiling process, is as follows:

[0059]

[0060] where σ T is the winding tension, P is the radial compressive stress of the strip under the winding tension, r is the radius of the barrel, and t is the thickness of the strip;

[0061] 2) According to the axisymmetric mechanical distribution theory:

[0062]

[0063]

[0064] σ rθ = 0

[0065] where σ θ is the circumferential (tangential stress); σ r is the radial stress; σ rθ is the shear stress; A and C are constants, which are mainly determined according to the boundary conditions;

[0066] 3) Assuming that the winding drum is a rigid object, and its inner radius is a m , the outer radius of the steel coil is b, and p0 is the internal pressure stress when winding a layer, then the radial and circumferential stresses satisfy:

[0067]

[0068]

[0069] 4) The forming process of the steel coil is a process of continuously increasing the strip, and then the stress distribution after winding can be calculated by the iterative method according to all the equations of 1)-3), including the circumferential stress and the radial stress distribution.

[0070] Step (4) Calculation of circumferential and radial stresses during the removal of the winding drum: the stress calculation during the removal of the winding drum under the existing working conditions can be considered to satisfy the following conditions: a positive stress is applied at the inner diameter of the steel coil, and the absolute value is exactly equal to the radial compressive stress at the inner diameter of the steel coil after winding is completed, and the radial stress at the outer diameter of the steel coil is zero (after winding is completed, the outer side of the steel coil is in a radial free state), and thus the stress distribution after the removal of the winding drum can be calculated;

[0071] Step (5) Experimental verification of the critical stress of the malignant edge wave of the inner circle of the strip: the malignant edge wave refers to the situation that the amplitude, period, etc. of the edge wave cannot meet the customer's requirements. According to the actual unwinding situation, the length of the inner circle of the strip with malignant edge wave under the existing winding working conditions is recorded, and the stress distribution after the removal of the winding drum is calculated, and the circumferential stress corresponding to the length of the malignant edge wave is recorded as σk;

[0072] Step (6) New coiling process and die parameters: For the same specification of the strip, adjust the coiling tension, the size of the coiling drum, the number of layers (the weight of the coil) and other parameters to form a new coiling process and die parameters.

[0073] Step (7) Circumferential and radial stress calculation during the coiling process: according to the calculation method in step (3) and the new coiling process and die parameters in step (6), the coiling tension distribution is recalculated;

[0074] Step (8) Circumferential and radial stress calculation during the removal of the coiling drum: based on the stress distribution calculated in step (7) during the coiling process, according to the calculation method in step (4), the stress distribution after the removal of the coiling drum under the new coiling process and die parameters is calculated.

[0075] Step (9) Comparison of the stress under the new coiling condition and the critical stress of the malignant edge wave: the stress calculated in step (8) is compared with σk obtained in step (5), if the circumferential stress of the innermost circle of the strip under the new coiling process is ≤σk (absolute value comparison), it means that the new adjusted coiling process can obtain a steel coil without malignant edge wave, and the parameters formed in step (6) are the new coiling process and die parameters without malignant edge wave of the inner circle of the strip; if the circumferential stress of the innermost circle of the strip under the new coiling process is >σk (absolute value comparison), it means that the coiling tension, the size of the coiling drum, the number of layers (the weight of the coil) and other parameters need to be further adjusted, and the process starts again from step (6).

[0076] Step (10) Whether the new coiling process leads to collapse, which is as follows:

[0077] If the "new coiling process and die parameters without malignant edge wave of the inner circle of the strip" are determined in step (9), the actual coiling is further carried out according to the die and process parameters, and it is observed whether the collapse phenomenon occurs, if not, the process parameters determined in step (9) are the new coiling process and die parameters balanced between the edge wave of the inner circle of the strip and the complete steel coil, and the prediction and control of the edge wave of the inner circle of the strip in the cold coiling process of the strip is ended; if the collapse occurs, the die and coiling process parameters need to be adjusted again, i.e. back to step (6).

[0078] Specific embodiment: see Figures 1-5 , in the experimental stage, the cold coiling process of the aluminum-zinc plated strip in a certain steel plant is taken as an example to explain in detail the method for predicting and controlling the formation of the edge wave of the inner circle of the strip in the cold coiling process of the strip.

[0079] A method for predicting and controlling the formation of the edge wave of the inner circle of the strip in the cold coiling process of the strip, which comprises the following steps:

[0080] Prediction and control of the formation of the coiling edge wave of the inner circle:

[0081] Step (1) Die parameters collection of coiler set: inner diameter of coiler: 300mm, outer diameter of coiler: 508mm.

[0082] Step (2) Parameters collection of strip and coiling process: outer diameter of coil: 1948mm (coiling layers: 1600 layers), thickness of strip: 0.45mm, coiling tension: 37MPa.

[0083] Step (3) Circumferential and radial stress calculation during coiling process: the coiling process of strip is considered as a process of gradually increasing the thin-walled barrel with internal pressure to a cylinder, as shown in Figure 1, which is a schematic diagram of coiling n+1 layers. With each layer coiled, the stress in the coiled strip will change, i.e. when the n+1 layer is coiled, the stress in the n layers of coiled strip will change. The basic principles of stress calculation during coiling process include: Figure 2

[0084] 1) The relationship between coiling tension and thickness of strip and internal pressure of strip (radial stress during single layer coiling process) is:

[0085]

[0086] where σ T is the coiling tension of the strip, P is the radial pressure stress of the strip under the action of coiling tension, r is the radius of the barrel, t is the thickness of the strip (0.45mm);

[0087] 2) According to the theory of axisymmetric mechanical distribution:

[0088]

[0089]

[0090] σ rθ = 0

[0091] where σ θ is the circumferential (tangential stress); σ r is the radial stress; σ rθ is the shear stress; A and C are constants, which are mainly determined according to the boundary conditions.

[0092] 3) Assuming that the coiler is a rigid object and its inner radius is am=150mm, the outer diameter of the coil is b (the outer radius of the coil when the n layer is coiled), p0 is the internal pressure when a layer is coiled, then the radial and circumferential stresses satisfy:

[0093]

[0094]

[0095] ​4) The formation process of the steel coil involves the continuous increase of strip coils. Therefore, based on all the equations in 1)-3), the stress distribution after coiling, including circumferential and radial stress distributions, can be calculated using a cyclic iterative method. Figure 3 As shown. Step (4) Calculation of circumferential and radial stresses during the drum removal process: The drum removal process can be considered to satisfy the following conditions: A normal stress is applied at the inner diameter of the steel coil, the absolute value of which is exactly equal to the radial compressive stress at the inner diameter of the steel coil after winding. Figure 3 When the thickness of the steel coil is 0, the corresponding radial stress is -37.3 MPa, while the radial stress at the outer diameter of the steel coil is zero (after winding, the outer side of the steel coil is in a radially free state). Therefore, the stress distribution after the coil is removed can be calculated. Figure 3 As shown;

[0096] Step (5) Experimental verification of the critical stress for the formation of malignant edge waves in the inner ring of the strip: The malignant edge waves refer to the situation where the amplitude, period, etc. of the edge waves cannot meet the customer service requirements. Based on the actual situation after uncoiling, the length of the inner ring strip with malignant edge waves under the existing winding conditions is recorded (100m in this embodiment), and the stress distribution after the roll is removed is calculated by comparison. The circumferential stress corresponding to the length of the malignant edge waves is denoted as σ. k = -65MPa, such as Figure 4 As shown;

[0097] Step (6) New winding process and tooling parameters: For strip of the same specification, adjust the winding tension to 27MPa, and keep the other parameters unchanged, the same as steps (1) and (2);

[0098] Step (7) Calculation of circumferential and radial stress during the winding process: Based on the calculation method in step (3) and the new winding process and die parameters in step (5), recalculate the winding tension distribution;

[0099] Step (8) Calculation of circumferential and radial stress during the roll removal process: Based on the stress distribution during the winding process calculated in step (7), and according to the calculation method in step (4), calculate the stress distribution after roll removal under the new winding process and die parameter conditions, such as Figure 5 As shown.

[0100] Step (9) Comparison of stress under the new winding condition with critical stress of severe edge waves: Compare the stress calculated in step (8) with σk obtained in step (5), as follows: Figure 5 As shown, when the winding tension is adjusted to 27 MPa, the circumferential stress of the innermost strip is -61 MPa, and its absolute value is ≤ σ. k (Comparison of absolute values) shows that the newly adjusted coiling process can produce steel coils without severe edge waviness.

[0101] Step (10) whether the new coiling process leads to collapse: after adjusting the coiling tension (reduced by 27%), the actual coiling shows that the problem of poor coiling of the inner circle is significantly improved, the customer has no reaction to the coiling problem, and the steel coil will not collapse, which proves the rationality of the new coiling process.

[0102] It should be noted that the above examples are not intended to limit the scope of the present application, and any equivalent transformations or substitutions made on the basis of the above technical solutions fall within the scope of the claims of the present application.

Claims

1. A method for predicting and controlling the formation of inner loop edge waves in a strip steel cold coiling process, characterized in that, The method comprises the following steps: Step (1) collecting parameters of the work die of the coiling unit, Step (2) collecting parameters of the strip and the coiling process, Step (3) calculating circumferential and radial stresses in the coiling process, Step (4) calculating circumferential and radial stresses in the process of removing the coiling drum, Step (5) experimentally verifying the critical stress of the formation of the malignant edge wave of the inner circle of the strip, Step (6) new coiling process and work die parameters, Step (7) calculating circumferential and radial stresses in the coiling process, Step (8) calculating circumferential and radial stresses in the process of removing the coiling drum, Step (9) comparing the stress under the new coiling condition with the critical stress of the malignant edge wave, Step (10) determining whether the new coiling process causes the collapse of the coil, if yes, returning to step (6), and if no, ending the control. In step (5), the length of the inner circle of the strip with the malignant edge wave under the existing coiling condition is recorded according to the actual uncoiling situation, and the stress distribution after the removal of the coiling drum is obtained by comparison, and the circumferential stress corresponding to the length of the malignant edge wave is denoted as σk. In step (6), the coiling tension, the size of the coiling drum and the number of coiling layers are adjusted for the same specification of the strip to form a new set of coiling process and work die parameters. In step (9), the stress obtained in step (8) is compared with σk obtained in step (5), and if the circumferential stress of the innermost circle of the strip under the new coiling condition is less than or equal to σk in the absolute value, it is indicated that the new coiling process can obtain the steel coil without the malignant edge wave, and the parameters obtained in step (6) are the new coiling process and work die parameters without the malignant edge wave of the inner circle of the strip; if the circumferential stress of the innermost circle of the strip under the new coiling condition is greater than σk in the absolute value, it is indicated that the coiling tension, the size of the coiling drum and the number of coiling layers need to be further adjusted, and the process starts again from step (6).

2. The method of predicting and controlling inner ring edge wave formation in a strip steel cold coiling process according to claim 1, characterized in that, In step (1), the parameters of the work die of the coiling unit are collected as follows: the inner and outer diameters of the coiling drum of the coiling unit for the strip with the serious inner circle coiling failure, i.e., the edge wave problem, are collected. In step (2), the parameters of the strip and the coiling process are collected, and the thickness, the coiling tension and the number of coiling layers of the strip for the coiling unit with the serious inner circle coiling failure, i.e., the edge wave problem, are collected to provide necessary data for the calculation of the stress distribution in the coiling process.

3. The method of claim 2, wherein the method further comprises: determining a target inner diameter of the inner ring; and determining a target inner ring thickness of the inner ring. In step (3), the circumferential and radial stresses in the coiling process are calculated as follows: 1) according to the relationship between the internal pressure and the circumferential stress of the thin-walled shell type barrel, the relationship between the coiling tension and the thickness of the strip and the pressure stress of the strip, i.e., the radial stress in the single-layer coiling process, is: where σ T is the take-up tension experienced by the strip, P is the radial compressive stress induced in the strip by the take-up tension, r is the radius of the barrel, and t is the thickness of the strip. 2) according to the axisymmetric mechanical distribution theory: σ rθ = 0 where σ θ is the circumferential tangential stress; σ r is the radial stress; σ rθ is the shear stress; A and C are constants, determined primarily by the boundary conditions; 3) Assuming the roll is a rigid body, and its inner radius is a m , the outer radius of the steel roll is b, p0 is the internal pressure stress when winding a layer, the radial and circumferential stresses satisfy: 4) the formation process of the steel coil is a process of continuously increasing the strip, and the stress distribution after the coiling can be obtained by the cyclic iteration method according to all the equations of 1)-3), including the circumferential stress and the radial stress distribution.

4. The method of claim 3, wherein the method further comprises: determining a target inner diameter of the inner ring; and determining a target inner ring thickness of the inner ring. Step (4) calculation of circumferential and radial stress during removal of the mandrel: a normal stress is applied at the inner diameter of the coil, and its absolute value is equal to the radial compressive stress at the inner diameter of the coil after the coiling is completed, while the radial stress at the outer diameter of the coil is zero, i.e. the outer side of the coil is in a radial free state after the coiling is completed, and thus the stress distribution after removal of the mandrel can be calculated.

5. The method of inner ring edge wave formation prediction and control in a strip cold mill process according to claim 4, characterized in that, Step (7) calculation of circumferential and radial stress during coiling: according to the calculation method in step (3) and the new coiling process and die parameters in step (6), the coiling tension distribution is recalculated; Step (8) calculation of circumferential and radial stress during removal of the mandrel: based on the stress distribution during coiling calculated in step (7), the stress distribution after removal of the mandrel under the condition of the new coiling process and die parameters is calculated according to the calculation method in step (4).

6. The method of inner ring edge wave formation prediction and control in a strip cold mill process according to claim 5, characterized in that, Step (10) whether the new coiling process leads to coil collapse, which is as follows: If the "new coiling process and die parameters without malignant edge waves in the inner circle of the strip" are determined in step (9), the actual coiling is further carried out according to the die and process parameters, and it is observed whether the coil collapse phenomenon occurs. If no coil collapse occurs, the process parameters determined in step (9) are the new coiling process and die parameters balanced between the edge waves of the inner circle of the strip and the complete coil, and the prediction and control of the edge waves of the inner circle of the strip in the cold coiling process of the strip are ended. If the coil collapse occurs, the die and coiling process parameters need to be adjusted again, i.e. back to step (6).

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