Automatic control method for edge wave defect of cold continuous rolling steel coil

Abstract

The application discloses an automatic control method for cutting edge wave defects of a cold continuous rolling steel coil, which comprises the following steps: first, the strip steel of the steel coil is divided into n sections according to the length direction of the steel coil with unit length as the position interval, and the temperature data of the n sections of the strip steel in the hot rolling process are respectively output to form a steel coil hot rolling temperature data set T; then, the total work roll bending force correction set value in the cold continuous rolling process is calculated according to the steel coil hot rolling temperature data set T, and the total work roll bending force correction set value is distributed to the work roll and the intermediate roll; finally, it is judged whether the bending force needs to be compensated in the continuous rolling process, and if the compensation is needed, the bending force compensation is performed; since the application can automatically compensate the bending force set value in the cold continuous rolling process to match the actual rolling force of the hot rolling steel coil, the problem of the cutting edge wave defects can be automatically solved in the whole process, and meanwhile, since no new device is added and only the cold rolling control method is improved, the cost is saved.

Description

Technical Field

[0001] This invention relates to an automatic control method for shear edge waviness defects in cold-rolled steel coils, belonging to the field of cold rolling control technology. Background Technology

[0002] Before hot-rolled steel coils enter the cold rolling mill, operators calculate a preset cold rolling force based on the average deformation resistance of the hot-rolled steel coil. Based on this preset force, they set the bending roll force during the cold rolling process. After setting, the hot-rolled steel coil is rolled on the cold rolling mill. During the rolling process, it is observed that edge waviness defects appear when the tail strip of the hot-rolled steel coil enters the fifth stand of the cold rolling mill for shearing. Due to tension loss during the cold rolling shearing process, the shape detection is distorted, making it impossible to improve the edge waviness defects generated after shearing through shape feedback control. This results in irreparable shear edge waviness defects at the tail of the steel coil. Technicians discovered that the reason for the shear edge waviness defects at the tail of the hot-rolled steel coil during cold rolling is that the deformation resistance of the tail strip is greater than the average deformation resistance. This causes the set bending roll force during rolling of the tail strip on the cold rolling mill to be less than the actual required rolling force, thus resulting in edge waviness defects during shearing. Technicians also discovered that the high deformation resistance of the strip at the tail end of the hot-rolled steel coil is due to the fact that the final rolling temperature of a small section of strip at the tail end of the hot-rolled steel coil during the tail-end rolling process is significantly lower than the set final rolling temperature for hot rolling. This lower final rolling temperature at the tail end directly leads to coarser grain structure at the head end, resulting in a higher deformation resistance at that location compared to the average deformation resistance of the entire coil. Therefore, existing technologies mainly employ the following two methods to address shear edge waviness defects in steel coils during cold rolling: 1. Adding a heat preservation device during hot rolling to maintain the final rolling temperature of the strip at the tail end of the hot-rolled steel coil, ensuring that the deformation resistance of the strip at the tail end does not exceed the average deformation resistance. 2. Manually adjusting the bending roll force based on experience during cold continuous rolling to match the bending roll force for shearing the strip at the tail end of the hot-rolled steel coil with the required rolling force, thus avoiding shear edge waviness defects. The problem with existing technology one is that it requires adding new equipment during the hot rolling process, which is too costly. The problem with existing technology two is that manual compensation for bending roll force is only suitable for small-scale rolling at slow speeds, and it is difficult to perform manual compensation for bending roll force in large-scale cold continuous rolling. Summary of the Invention

[0003] The technical problem to be solved by this invention is: how to automatically adjust the bending roll force compensation value during the rolling process so that the bending roll force matches the actual rolling force, thereby solving the shear edge wave defect that occurs in steel coils during cold continuous rolling.

[0004] The technical solution proposed in this invention is: an automatic control method for shear edge waviness defects in cold-rolled steel coils, which collects the final rolling temperature setpoint T of the steel coil during the hot rolling process. z The strip width B of the steel coil, and the width influence coefficient of the strip width B. , adjustment coefficient of bending force compensation conversion , effective coefficient of bending force compensation conversion parameters, and performing the following steps:

[0005] Step 1: Before cold rolling, the strip of the steel coil is divided into n sections according to the length direction of the steel coil with unit length as the position interval, n is a natural number greater than 2; the temperature data of the n sections of the strip in the hot rolling process is output to form a steel coil hot rolling temperature data set T, as shown in the following formula (1),

[0006] (1),

[0007] In formula (1), is the temperature data of the first section of the strip of the steel coil in the hot rolling process; is the temperature data of the second section of the strip of the steel coil in the hot rolling process; is the temperature data of the last section of the strip of the steel coil in the hot rolling process;

[0008] The last A section of the strip in the length direction of the steel coil is selected as the tail section of the strip of the steel coil, A is a natural number greater than 0 and less than n;

[0009] The hot rolling tail average temperature output value T of the tail section of the strip is calculated by the following formula (2) w ,

[0010] (2);

[0011] Step 2: Set the bending force of the base work roll in the cold rolling process The total work roll bending force set value in the cold rolling process is calculated by the following formula (3) ,

[0012] (3),

[0013] In formula (3), k is the temperature difference proportion coefficient;

[0014] The total work roll bending force correction set value in the cold rolling process is calculated by the following formula (4) ,

[0015] (4),

[0016] The total work roll bending force correction set value is distributed to the work roll and the intermediate roll in the cold rolling process by the following formulas (5) and (6) to obtain the work roll bending force set value of the work roll and the intermediate roll bending force set value of the intermediate roll ,

[0017] (5),

[0018] In formula (5), a is the total work roll bending force correction setting value of the work roll, b is the total work roll bending force correction setting value of the intermediate roll;

[0019] (6),

[0020] In formula (6), c is the conversion ratio between the work roll bending force and the intermediate roll bending force;

[0021] According to the work roll bending force setting value of the work roll and the intermediate roll bending force setting value of the intermediate roll , the corresponding bending forces are output respectively for rolling;

[0022] Step 3: based on step 2, set a judgment period T, and divide the whole cold continuous rolling process into m judgment periods T by formula (7) below,

[0023] (7),

[0024] Judge the actual rolling force P of the fifth stand of the cold continuous rolling mill in the first judgment period T, and see whether the bending force compensation is needed, if needed, execute the following step 4; if not needed, judge the total rolling force P in all the following judgment periods T in turn;

[0025] The specific judgment process is as follows:

[0026] Step 3.1: collect the total rolling force of the fifth stand in the i-th judgment period T , and calculate the unit rolling force distributed in the width direction of the steel coil strip in the judgment period T by formula (8) below ,

[0027] (8);

[0028] Step 3.2: calculate the rolling force difference by formula (9) below ,

[0029] (9),

[0030] In formula (8), is the unit rolling force distributed in the width direction of the steel coil strip in the i-1-th judgment period T;

[0031] The judgment variable in the i-th judgment period T is obtained by the following formula (10) ,

[0032] (10),

[0033] In formula (10), is the judgment variable in the i-1-th judgment period T; is the intermediate variable in the i-th judgment period T, is the conversion coefficient;

[0034] If the judgment variable in the i-th judgment period T satisfies the following formula (11), it is considered that the bending roll force compensation is not needed, otherwise, it is considered that the bending roll force compensation is needed,

[0035] (11);

[0036] Step 4: The bending roll force compensation value for the bending roll force compensation is calculated by the following formula (12) ,

[0037] (12),

[0038] If the bending roll force compensation value is greater than 1 ton, the bending roll force compensation value is adjusted to 1T and output for the bending roll force compensation, if the bending roll force compensation value is less than 1 ton, the bending roll force compensation value is directly output for the bending roll force compensation.

[0039] The present application has the following advantages: the present application can automatically compensate the bending roll force set value to match the actual rolling force of the hot-rolled steel coil in the cold continuous rolling process, so that the problem of the shear edge wave defect of the hot-rolled steel coil in the existing cold continuous rolling process can be automatically solved, and since no new device is added and only the control method of the cold continuous rolling is improved, the cost is greatly saved. DETAILED DESCRIPTION

[0040] The present application will be further described below in combination with the specific embodiments

[0041] The present application is an automatic control method for the shear edge wave defect of a cold continuous rolling steel coil, which collects the finishing temperature set value T z of the steel coil in the hot rolling process, the strip width B of the steel coil, the width influence coefficient of the strip width B, and the adjustment coefficient of the bending roll force compensation conversion and effective coefficient of bending force compensation conversion parameters and performing the following steps:

[0042] Step 1: Before cold continuous rolling, the strip of the steel coil is divided into n sections according to the length direction of the steel coil with unit length as the position interval, n is a natural number greater than 2; the temperature data of the n sections of the strip in the hot rolling process is output to form a steel coil hot rolling temperature data set T, as shown in the following formula (1),

[0043] (1),

[0044] In formula (1), is the temperature data of the first section of the strip of the steel coil in the hot rolling process; is the temperature data of the second section of the strip of the steel coil in the hot rolling process; is the temperature data of the last section of the strip of the steel coil in the hot rolling process;

[0045] The last A section of the strip in the length direction of the steel coil is selected as the tail section of the strip of the steel coil, A is a natural number greater than 0 and less than n;

[0046] The hot rolling tail average temperature output value T of the tail section of the strip is calculated by the following formula (2) w ,

[0047] (2) ;

[0048] Step 2: Set the bending force of the base work roll in the cold continuous rolling process The total work roll bending force set value in the cold continuous rolling process is calculated by the following formula (3) ,

[0049] (3),

[0050] In formula (3), k is the temperature difference proportion coefficient;

[0051] The total work roll bending force correction set value in the cold continuous rolling process is calculated by the following formula (4) ,

[0052] (4),

[0053] The total work roll bending force correction set value is distributed to the work roll and the intermediate roll in the cold continuous rolling process by the following formulas (5) and (6) to obtain the work roll bending force set value of the work roll and the intermediate roll bending force set value of the intermediate roll ,

[0054] (5),

[0055] In formula (5), a is the total work roll bending force correction setting value the proportion of the work roll when the distribution is made, b is the total work roll bending force correction setting value the proportion of the intermediate roll when the distribution is made;

[0056] (6),

[0057] In formula (6), c is the conversion proportion between the work roll bending force and the intermediate roll bending force;

[0058] According to the work roll bending force setting value of the work roll and the intermediate roll bending force setting value of the intermediate roll corresponding bending forces are respectively output for rolling;

[0059] Step 3: on the basis of step 2, when rolling is performed, a judgment period T is set, and the whole cold continuous rolling process is divided into m judgment periods T by formula (7) below,

[0060] (7),

[0061] In formula (7), is the time for which cold continuous rolling is performed;

[0062] The actual rolling force P of the fifth stand of the cold continuous rolling mill in the first judgment period T is judged to see whether bending force compensation is needed, and if needed, the following step 4 is performed; if not needed, the total rolling force P in all the judgment periods T is sequentially judged;

[0063] The specific judgment process is as follows:

[0064] Step 3.1: the total rolling force P of the fifth stand in the i-th judgment period T is collected The unit rolling force distributed in the width direction of the steel coil strip in the judgment period T is calculated by formula (8) below ,

[0065] (8);

[0066] Step 3.2: the rolling force difference is calculated by formula (9) below ,

[0067] (9),

[0068] In formula (8), is a unit rolling force distributed in the steel coil strip width direction in the i-1th judgment period T;

[0069] The judgment variable in the i-th judgment period T is obtained by the following formula (10) ,

[0070] (10),

[0071] In formula (10), is the judgment variable in the i-1th judgment period T; is an intermediate variable in the i-th judgment period T, is a conversion coefficient;

[0072] If the judgment variable in the i-th judgment period T satisfies the following formula (11), it is considered that no bending roll force compensation is needed, otherwise, it is considered that bending roll force compensation is needed,

[0073] (11);

[0074] Step 4: The bending roll force compensation value for bending roll force compensation is calculated by the following formula (12) ,

[0075] (12),

[0076] If the bending roll force compensation value is greater than 1 ton, the bending roll force compensation value is adjusted to 1T and output for bending roll force compensation, if the bending roll force compensation value is less than 1 ton, the bending roll force compensation value is directly output for bending roll force compensation.

Claims

1. A method for automatic control of edge wave defects in a cold-rolled steel coil, characterized in that: collecting a finish rolling temperature setting value T of the steel coil in a hot rolling process z , a strip width B of the steel coil, a width influence coefficient of the strip width B , an adjustment coefficient of a bending roll force compensation conversion , and an effective coefficient of the bending roll force compensation conversion parameters, and performing the following steps: Step 1: before cold continuous rolling, the strip of the steel coil is divided into n sections according to the length direction of the steel coil with unit length as the position interval, n is a natural number greater than 2; the temperature data of the n sections of the strip in the hot rolling process are output to form a steel coil hot rolling temperature data set T, as shown in the following formula (1), （1）， In formula (1), is temperature data of a first section of strip steel of the steel coil in a hot rolling process; is temperature data of a second section of strip steel of the steel coil in a hot rolling process; is temperature data of a last section of strip steel of the steel coil in a hot rolling process; The last A section of the strip in the length direction of the steel coil is selected as the tail section of the strip of the steel coil, A is a natural number greater than 0 and less than n; The hot rolling tail average temperature output value T of the tail strip section is calculated by the following formula (2) w , （2）； Step 2: Setting the bending force of the work rolls in the cold continuous rolling process The total bending force setting value of the work rolls in the cold continuous rolling process is calculated by the following equation (3) , （3）， In formula (3), k is a temperature difference proportionality coefficient; The total work roll bending force correction set value in the cold continuous rolling process is calculated by the following formula (4) , （4）， The total work roll bending roll force correction set value is calculated by the following equations (5) and (6) The work roll bending roll force set value of the work roll and the intermediate roll in the cold continuous rolling process is sequentially allocated to obtain the work roll bending roll force set value of the work roll and the intermediate roll bending roll force set value of the intermediate roll , （5）， In formula (5), a is the total work roll bending force correction set value the proportion of the work roll in the distribution, b is the total work roll bending force correction set value the proportion of the intermediate roll in the distribution; （6）， In formula (6), c is a conversion proportionality between the bending force of the work roll and the bending force of the intermediate roll; a work roll bending force set value of the work roll a work roll bending force set value of the work roll respectively output corresponding bending forces for rolling; Step 3: when rolling on the basis of step 2, a judgment period T is set, and the whole cold continuous rolling process is divided into m judgment periods T by the following formula (7), （7）， In formula (7), is the time for cold continuous rolling; The actual rolling force P of the fifth stand of the cold continuous rolling mill in the first judgment period T is judged to see whether the bending force compensation is needed, if needed, step 4 is executed; if not needed, the total rolling force P in the following all judgment periods T is judged in turn; The specific judgment process is as follows: Step 3.1: Collect the total rolling force of the fifth stand in the i-th judgment period T The unit rolling force distributed in the steel strip width direction in the judgment period T is calculated by the following formula (8) , （8）； Step 3.2: Calculate the rolling force difference by the following formula (9) , （9）， In formula (8), is the unit rolling force in the width direction of the steel coil strip in the i-1th judgment period T. The judgment variable in the i-th judgment period T is obtained by the following equation (10) , （10）， In formula (10), is a judgment variable in the i-1th judgment period T; is an intermediate variable in the i-th judgment period T, is a conversion coefficient; If the judging variable in the i-th judging period T satisfies the following formula (11), it is considered that the bending roll force compensation is not needed, otherwise, it is considered that the bending roll force compensation is needed. If the judging variable in the i-th judging period T satisfies the following formula (11), it is considered that the bending roll force compensation is not needed, otherwise, it is considered that the bending roll force compensation is needed. （11）； Step 4: The bending roll force compensation value for bending roll force compensation is calculated by the following formula (12) , （12）， If the bending roll force compensation value is greater than 1 ton, the bending roll force compensation value is adjusted to 1 T and output for bending roll force compensation, if the bending roll force compensation value is less than 1 ton, the bending roll force compensation value is output directly for bending roll force compensation.

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