Method for controlling shearing edge wave defect of cold continuous rolling steel coil

Abstract

According to the control method for the shearing edge wave defect of the cold continuous rolling steel coil, the final rolling temperature set value Tz of the steel coil in the hot rolling process is collected, and the following steps are executed: firstly, strip steel of the steel coil is divided into n sections according to the length direction of the steel coil with the unit length as the position interval, respectively outputting the temperature data of the n sections of strip steel in the hot rolling process to form a steel coil hot rolling temperature data set T; then, according to the steel coil hot rolling temperature data set T, a total working roll bending force correction set value in the cold continuous rolling process is obtained through calculation, and the total working roll bending force correction set value is distributed to a working roll and an intermediate roll; the roll bending force set value in the cold rolling process is corrected according to the difference value between the actual rolling temperature of the steel coil in the hot rolling process and the set finish rolling temperature, so that the roll bending force in the cold continuous rolling process is matched with the rolling force required by the steel coil; and the problem of the shearing edge wave defect of the hot rolled steel coil in the existing cold continuous rolling process is greatly relieved.

Description

Technical Field

[0001] The invention relates to a method for controlling shear edge wave defects of a cold-rolled steel coil, and belongs to the technical field of cold-rolling control. Background Art

[0002] Before the hot-rolled steel coil is put into the cold rolling mill, the operator will calculate the preset cold rolling force according to the average deformation resistance of the hot-rolled steel coil, and set the bending roll force during the cold rolling process according to the preset cold rolling force. After the setting is completed, the hot-rolled steel coil is rolled in the cold rolling mill. During the rolling process, it is found that when the tail strip of the hot-rolled steel coil enters the fifth stand of the cold rolling mill for shearing, edge wave defects will appear. Due to the tension loss in the cold rolling shearing process, the plate shape detection is distorted, so that the edge wave defects generated after shearing cannot be improved by plate shape feedback control, resulting in irreparable shear edge wave defects at the tail of the steel coil. The technicians found that the reason why the shear edge wave defect occurs at the tail strip of the hot-rolled steel coil during cold rolling is that the deformation resistance of the tail strip of the hot-rolled steel coil is greater than the average deformation resistance, resulting in the bending roll force set when the cold rolling mill rolls the tail strip of the hot-rolled steel coil smaller than the actually required rolling force, so the edge wave defect occurs during shearing. The technicians also found that the reason why the deformation resistance of the tail strip of the hot-rolled steel coil is large is that the final rolling temperature of a small section of the strip at the tail of the hot-rolled steel coil during the tail-swinging rolling process is significantly lower than the final rolling temperature set for hot rolling. The lower final rolling temperature at the tail directly leads to the coarse grain structure of the head, and the deformation resistance of the material at the corresponding position is higher than the average deformation resistance of the entire coil of material. Therefore, there are mainly two methods in the prior art to solve the shear edge wave defects of steel coils during cold rolling: First, add a heat preservation device during the hot rolling process to maintain the final rolling temperature of the tail strip of the hot-rolled steel coil, so that the deformation resistance of the tail strip of the hot-rolled steel coil is not higher than the average deformation resistance. Second, manually adjust the bending roll force according to experience during the cold rolling process, so that the bending roll force of the shearing tail strip of the hot-rolled steel coil matches the required rolling force to avoid shear edge wave defects. The problem with the first prior art is that new equipment needs to be added during the hot rolling process, which is too costly. The problem with the second prior art is that manual compensation for the bending roll force is only applicable to small-scale and slow rolling situations, and it is difficult to manually compensate for the bending roll force in large-scale cold rolling. Summary of the invention

[0003] The technical problem to be solved by the present invention is: how to adjust the preset value of the bending roll force during the rolling process so that the bending roll force matches the actual rolling force, thereby solving the shear edge wave defect of the steel coil during the cold rolling process.

[0004] The technical solution proposed by the present invention is: a method for controlling the shear edge wave defects of cold rolled steel coils, collecting the final rolling temperature setting value T of the steel coils during the hot rolling process z , and perform the following steps:

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

[0006] T={T1, T2, ..., T n}(1),

[0007] In formula (1), T1 is the temperature data of the first strip of the steel coil during the hot rolling process; T2 is the temperature data of the second strip of the steel coil during the hot rolling process; T n is the temperature data of the last strip of the steel coil during the hot rolling process;

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

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

[0010] T w = (T n +T n-1 +T n-2 +...+T n-A ) / A (2);

[0011] Step 2: Set the base work roll bending force ΔWRB5 during cold rolling B The total working roll bending force setting value ΔWRB5 during cold rolling is calculated by the following formula (3): T ,

[0012]

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

[0014] The total work roll bending force correction setting value ΔWRB5' during the cold rolling process is calculated by the following formula (4):

[0015] ΔWRB5'=ΔWRB5 B +ΔWRB5 T (4)

[0016] The total work roll bending force correction setting value ΔWRB5' is distributed to the work rolls and the intermediate rolls in the cold rolling process in sequence through the following formulas (5) and (6) to obtain the work roll bending force setting value ΔWRB5 of the work roll and the intermediate roll bending force setting value ΔIRB5 of the intermediate roll.

[0017]

[0018] In formula (5), a is the proportion of the working rolls when the total working roll bending force correction setting value ΔWRB5' is distributed, and b is the proportion of the intermediate rolls when the total working roll bending force correction setting value ΔWRB5' is distributed;

[0019]

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

[0021] According to the working roll bending force setting value ΔWRB5 of the working roll and the intermediate roll bending force setting value ΔIRB5 of the intermediate roll, the corresponding bending forces are output respectively for rolling.

[0022] The beneficial effects of the present invention are as follows: the present invention corrects the setting value of the bending roll force in the cold rolling process according to the difference between the actual rolling temperature of the steel coil in the hot rolling process and the set final rolling temperature, so that the bending roll force in the cold rolling process matches the rolling force required by the steel coil, which greatly alleviates the problem of shear edge wave defects in the hot-rolled steel coil in the existing cold rolling process. DETAILED DESCRIPTION

[0023] The following is a further description of a method for controlling shear edge wave defects of a cold rolled steel coil according to the present invention in conjunction with a specific embodiment.

[0024] The present invention provides a method for controlling shear edge wave defects of cold rolled steel coils, firstly collecting the final rolling temperature setting value T of the steel coils during hot rolling. z , then follow these steps:

[0025] Step 1: Divide the strip of the steel coil into n sections according to the length direction of the steel coil at a unit length interval, where n is a natural number greater than 2; output the temperature data of the n sections of the strip during the hot rolling process to form a steel coil hot rolling temperature data set T, as shown in the following formula (1):

[0026] T={T1, T2, ..., T n}(1),

[0027] In formula (1), T1 is the temperature data of the first strip of the steel coil during the hot rolling process; T2 is the temperature data of the second strip of the steel coil during the hot rolling process; T n is the temperature data of the last strip of the steel coil during the hot rolling process;

[0028] The last A sections of strip steel in the length direction of the steel coil are selected as the tail strip steel section of the steel coil, where A is a natural number greater than 0 and less than n;

[0029] The average temperature output value T of the hot rolling tail of the tail strip section is calculated by the following formula (2): w ,

[0030] T w = (T n +T n-1 +T n-2 +...+T n-A ) / A (2);

[0031] Step 2: Set the base work roll bending force ΔWRB5 during cold rolling B The total working roll bending force setting value ΔWRB5 during cold rolling is calculated by the following formula (3): T ,

[0032]

[0033] In formula (3), k is the temperature difference proportional coefficient;

[0034] The total work roll bending force correction setting value ΔWRB5' during the cold rolling process is calculated by the following formula (4):

[0035] ΔWRB5'=ΔWRB5 B +ΔWRB5 T (4)

[0036] The total work roll bending force correction setting value ΔWRB5' is distributed to the work rolls and the intermediate rolls in the cold rolling process in sequence through the following formulas (5) and (6) to obtain the work roll bending force setting value ΔWRB5 of the work roll and the intermediate roll bending force setting value ΔIRB5 of the intermediate roll.

[0037]

[0038] In formula (5), a is the proportion of the working rolls when the total working roll bending force correction setting value ΔWRB5' is distributed, and b is the proportion of the intermediate rolls when the total working roll bending force correction setting value ΔWRB5' is distributed;

[0039]

[0040] In formula (6), c is the conversion ratio between the working roll bending force and the intermediate roll bending force;

[0041] According to the working roll bending force setting value ΔWRB5 of the working roll and the intermediate roll bending force setting value ΔIRB5 of the intermediate roll, the corresponding bending forces are output respectively for rolling.

Claims

1. A method for controlling shear edge wave defects of cold rolled steel coils, characterized in that: Collect the final rolling temperature setting value T of the steel coil during the hot rolling process z , and perform the following steps: Step 1: Divide the strip of the steel coil into n sections according to the length direction of the steel coil at unit length intervals, where n is a natural number greater than 2; output the temperature data of the n sections of the strip during the hot rolling process to form a steel coil hot rolling temperature data set T, as shown in the following formula (1): T={T1、T2、...、T n }(1), In formula (1), T1 is the temperature data of the first strip of the steel coil during the hot rolling process; T1 is the temperature data of the second strip of the steel coil during the hot rolling process; T n is the temperature data of the last strip of the steel coil during the hot rolling process; The last A sections of strip steel in the length direction of the steel coil are selected as the tail strip steel section of the steel coil, where A is a natural number greater than 0 and less than n; The average temperature output value T of the hot rolling tail of the tail strip section is calculated by the following formula (2): w , T w = (T n +T n-1 +T n-2 +...+T n-A ) / A (2); Step 2: Set the base work roll bending force ΔWRB5 during cold rolling B The total working roll bending force setting value ΔWRB5 during cold rolling is calculated by the following formula (3): T , In formula (3), k is the temperature difference proportional coefficient; The total work roll bending force correction setting value ΔWRB5' during the cold rolling process is calculated by the following formula (4): ΔWRB5' = ΔWRB5 B +ΔWRB5 T (4) The total work roll bending force correction setting value ΔWRB5' is distributed to the work rolls and the intermediate rolls in the cold rolling process in sequence through the following formulas (5) and (6) to obtain the work roll bending force setting value ΔWRB5 of the work roll and the intermediate roll bending force setting value ΔIRB5 of the intermediate roll. In formula (5), a is the proportion of the working rolls when the total working roll bending force correction setting value ΔWRB5' is distributed, and b is the proportion of the intermediate rolls when the total working roll bending force correction setting value ΔWRB5' is distributed; In formula (6), c is the conversion ratio between the working roll bending force and the intermediate roll bending force; According to the working roll bending force setting value ΔWRB5 of the working roll and the intermediate roll bending force setting value ΔIRB5 of the intermediate roll, the corresponding bending forces are output respectively for rolling.

Images