KR102514894B1 - Method for controlling leveler to improve flatness of plate after rolling - Google Patents

Abstract

The present invention relates to a leveler control method for improving the flatness of a plate after rolling. A roll gap control method of a leveler, wherein the leveler is positioned so that a plurality of upper and lower rolls overlap each other vertically in a zigzag shape, comprises the steps of: obtaining the tensile strength (Ts) of a plate; obtaining a material width (W) representing the width of the plate; obtaining a material thickness (t) representing the thickness of the plate; proceeding with a leveling operation by controlling RGE representing the height difference between the bottom of the upper roll and the top of the lower roll at a leveler entrance depending on the tensile strength, material width, and material thickness and RGD representing the height difference between the bottom of the upper roll and the top of the lower roll at a leveler exit; and obtaining a material temperature (T) by measuring the temperature of the plate at the front end of the leveler; and proceeds with the leveling operation by controlling the RGE and RGD depending on the material temperature. Accordingly, by providing a leveler control method to ensure flatness by controlling the gap between the upper and lower rolls in the leveler based on the strength, temperature, and width of the material, the quality of the plate can be improved by reducing a flatness deviation.

Description

Method for controlling leveler to improve flatness of plate after rolling}

The present invention relates to a leveler control method for improving the flatness of a plate after rolling.

In general, thick plates (or plates) after hot rolling can satisfy the customer's desired flatness by working conditions, material properties, and crowns (thermal crowns, roll crowns) of rolling mills. has a missing factor. Thick plate refers to a steel plate with a thickness of 6 mm or more, and is distinguished from a thin plate with a thickness of less than 3 mm.

In order to satisfy the flatness of the thick plate, the flatness is controlled through a plurality of levelers in the thick plate rolling mill. The leveler refers to a device that arranges upper and lower rolls in a zigzag pattern and flattens the steel sheet by passing the steel sheet between the rollers.

Levelers include pre-levelers used in accelerated coolants and hot plate levelers used in all thick plate materials.

When the leveler flattens the plate, the height difference between the upper and lower rolls at the entrance and the height difference between the upper and lower rolls at the exit are controlled according to the strength and width of the material, so that the flatness of the plate is set to the desired level. there is.

However, since the leveling work using the leveler depends on the know-how of the work site, it is difficult to standardize the work, and accordingly, it is difficult to satisfy the flatness of the plate desired by the customer.

Republic of Korea Patent No. 10-1453598

Therefore, the present invention was invented in view of the above circumstances, and to provide a leveler control method for securing the flatness of a plate through control of the gap between the upper roll and the lower roll in the leveler based on the strength, temperature, and width of the material. There is a purpose in

A method for controlling a roll gap of a leveler for improving the flatness of a plate after rolling according to the present invention for realizing the object as described above is such that a plurality of upper rolls and lower rolls overlap each other vertically in a zigzag form. positioned and obtaining the tensile strength (Ts) of the plate; Obtaining a material width (W) representing the width of the plate; Obtaining a material thickness (t) representing the thickness of the plate; Depending on the tensile strength, material width and material thickness, RGE representing the height difference between the lower end of the upper roll and the upper end of the lower roll at the leveler inlet, and the RGD representing the height difference between the lower end of the upper roll and the upper end of the lower roll at the leveler outlet are controlled. performing a flattening operation; includes

In addition, measuring the temperature of the plate in front of the leveler to obtain a material temperature (T); Further, the planarization operation is performed by controlling the RGE and RGD according to the temperature of the material.

In addition, the step of determining whether to compensate for the entrance to differently control the RGE at the time of entering the leveler and the RGE after entering the leveler according to the thickness of the material; If it is determined that entry compensation is to be performed, facilitating entry of the material by controlling the RGE when the material enters the leveler to be greater than the RGE after entry; more includes

In addition, controlling the speed at which the plate moves in the leveler and the moving speed when the plate enters the leveler differently; more includes

In addition, the step of performing the flattening operation may include preparing a calibration table describing the RGE and RGD according to the material temperature, tensile strength, material width, and material thickness; performing a flattening operation by controlling the RGE and RGD according to the calibration table; includes

According to the present invention, by providing a leveler control method for securing the flatness of the plate by controlling the gap between the upper and lower rolls in the leveler based on the strength, temperature, and width of the material, the flatness deviation is reduced and the quality of the plate is reduced. can improve

1 is a diagram showing the configuration of a leveler of the present invention.
2 is a view for explaining a method for controlling a roll gap of a leveler according to the present invention.
3 is a diagram showing a calibration table of a leveler according to an embodiment of the present invention.

Hereinafter, the configuration and operation of a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are marked with the same numerals as much as possible, even if they are displayed on different drawings.

1 is a diagram showing the configuration of a leveler of the present invention. 2 is a view for explaining a method for controlling a roll gap of a leveler according to the present invention. 3 is a diagram showing a calibration table of a leveler according to an embodiment of the present invention.

The leveler roll gap control method of the present invention improves the problem of the flattening work using a leveler after rolling a plate (or thick plate) depending on the know-how of the work site without a clear standard, thereby improving the strength, temperature, width, and thickness of the material It is to control the gap between the upper roll and the lower roll of the leveler based on the desired quality of plate flatness.

The leveler 100 includes a lower roll support 110, lower rolls 111, 112, 113, 114, 115, 116, an upper roll support 120, and an upper roll 121, 122, 123, 124, 125, 126 , a temperature sensor 140, and the like.

A plurality of lower rolls 111, 112, 113, 114, 115, and 116 are spaced apart and supported by the lower roll support 110 to be positioned horizontally.

A plurality of upper rolls 121, 122, 123, 124, 125, and 126 are spaced apart and disposed between the lower rolls 111, 112, 113, 114, 115, and 116, and are supported by the upper roll support 120. It is supported and positioned inclined upward.

The upper rolls 121, 122, 123, 124, 125, and 126 and the lower rolls 111, 112, 113, 114, 115, and 116 are arranged to overlap each other in a zigzag pattern. Here, the overlapping arrangement means that the lower ends of the upper rolls 121, 122, 123, 124, 125, and 126 are lower than the upper ends of the lower rolls 111, 112, 113, 114, 115, and 116. say

The flatness of the plate 10 is improved by the force received from the rolls while passing between the upper rolls 121, 122, 123, 124, 125, and 126 and the lower rolls 111, 112, 113, 114, 115, and 116. do. In general, the upper rolls 121, 122, 123, 124, 125, and 126 are inclined upward, so that the force applied to the plate 10 decreases from the inlet to the outlet of the leveler 100.

The temperature sensor 140 is disposed at the front end of the leveler 100 and measures the temperature of the plate 10 flowing into the leveler 100 .

In the present invention, in order to control the leveler 100, the tensile strength (Ts), width (or material width) (W), thickness (or material thickness) (t), temperature (or material temperature) (T) of the plate 10 ) is obtained, and thus RGE (Roll Gap Entry) representing the height difference between the lower end of the upper roll and the upper end of the lower roll at the entrance of the leveler 100 and the height difference between the lower end of the upper roll and the upper end of the lower roll at the exit of the leveler 100 RGD (Roll Gap Delivery) is controlled to planarize the plate 10 .

2, the height difference between the bottom of the upper roll 121 and the top of the lower roll 111 at the entrance of the leveler 100 is indicated by RGE, and the lower end of the upper roll 125 and the lower roll 116 at the exit of the leveler 100 ), the height difference at the top is denoted by RGD. 2 shows that 5 upper rolls and 6 lower rolls are disposed, however, depending on the leveler 100, 6 upper rolls and 5 lower rolls may be disposed.

To this end, prepare a calibration table describing RGE and RGD according to material temperature (T), tensile strength (Ts), material width (W) and material thickness (t), and control RGE and RGD according to this calibration table to carry out the leveling operation.

First, as shown in Table 1, a plurality of first groups are grouped according to the ranges of material temperature (T) and tensile strength (Ts).

600℃ > T 600 <= T <= 800 800 < T note Ts < 40 G2 G1 G1
G1-G6
G5: DQ Material Spare
G6: STS Spare 40 <= Ts < 50 G2 G2 G1 50 <= Ts < 60 G3 G2 G2 60 <= Ts < 70 G3 G3 G2 70 <= Ts G4 G3 G3

Here, T refers to the temperature of the plate 10 before entering the leveler 100 after the end of rolling, which can be measured by the temperature sensor 140 located at the front end of the leveler 100. Ts refers to the tensile strength (kgf/mm ² ) according to the material properties of the plate 10 .

In Table 1, when the plate 10 has a temperature of 600 to 800 ° C and a tensile strength of 70 or more, it is classified as a G3 group, and when a tensile strength is 40 or more and less than 50, it is classified as a G2 group.

In Table 1, they were classified into G1 to G4 groups according to the temperature and tensile strength of the plate 10, and classified into G5 for DQ material spares and G6 for STS spares.

Next, as shown in Table 2, the first group classified according to the material temperature (T) and the tensile strength (Ts) is divided into a plurality of second groups according to the width (W) of the plate 10.

Unit: mm Grade W<2500 2500 <= W <= 3500 W > 3500 G1 G11 G12 G13 G2 G21 G22 G23 G3 G31 G32 G33 G4 G41 G42 G43 G5 G51 G52 G53 G6 G61 G62 G63

In Table 2, if the classification of the first group is G1 and the width (W) of the plate 10 is 2500 to 3500 mm, it is classified into the G12 group, and if the width (W) exceeds 3500 mm, it is classified into the G13 group.

Next, in the second group, a calibration table for controlling RGE and RGD according to the thickness t of the plate 10 is made, and RGE and RGD of the leveler 100 are controlled accordingly.

Referring to FIG. 3 , when the width (W) of the plate 10 is 2500≤W≤3500, RGE and RGD according to the thickness (t) are digitized and presented in the second group. When the name of the second group is G12 and the thickness (t) of the plate 10 is 6≤t<7, RGE is controlled to -2.3mm and RGD is controlled to -0.3mm. Here, - in RGE and RGD means that the lower end of the upper roll is lower than the upper end of the lower roll.

Leveling speed and plate entry speed (Metal in speed) are also written in the calibration table, and the leveler 100 is controlled accordingly. The leveling speed refers to a speed at which the plate 10 moves in the leveler 100, and the plate entry speed refers to a moving speed when the plate 10 enters the leveler 100. For example, in the case of t≤6 in the G12 group, the leveling speed is 70 mpm and the metal in speed is 42 mpm.

In addition, the third entry compensation on/off from the right in the calibration table (or whether or not to enter compensation) (Metal in comp' on/off) is the RGE and entry at the time of entry to facilitate entry into the leveler in the case of a thick plate. It determines whether to make the subsequent RGE different. 0 means that there is no entry compensation, and 1 means that there is entry compensation.

In FIG. 3, in the case of the plate 10 having a thickness t of 25 mm or more, entry compensation on/off is displayed as 1, which means entry compensation, and in this case, the C-RGE value is additionally described in the calibration table When the plate 10 enters, it is set to C-RGE, and after entering, it is controlled by RGE. C-RGE means compensated RGE, and refers to RGE before the plate 10 enters the leveler, and generally, C-RGE is larger than RGE to facilitate entry of the plate 10.

As described above, in the leveler control method of the present invention, a calibration table in which RGE and RGD are described according to the strength, temperature, width, and thickness of the plate 10 is created, and calibration is performed according to the RGE and RGD specified in the calibration table. , It is possible to secure the optimal flatness at the level required by the customer regardless of the operator or the work site.

In addition, by optimally controlling the leveler according to the calibration table, there is an advantage in that unnecessary load on equipment is reduced, leveler control suitable for the characteristics of the material is performed, and even plate speed optimal for securing flatness can be specified and controlled.

In addition, if the thickness of the material is very thick, the entry compensation on/off function is given to control the RGE before and after entry of the material differently, thereby increasing the indentability of the material and solving the problem of equipment accidents if the material is an ultra-high strength material. there is.

The control unit judges the material information in the upper controller L1 (SCC or PC) even if the operator does not know the state of the material and controls it to indicate the work value to L2 (PLC) according to the calibration table, so that the plate is always optimally flat. It is possible to control the leveler to ensure.

It is obvious to those skilled in the art that the present invention is not limited to the above embodiments and can be variously modified or transformed without departing from the technical gist of the present invention. will be.

10: plate
100: leveler
110: lower roll support
111, 112, 113, 114, 115, 116: lower roll
120: upper roll support
121, 122, 123, 124, 125, 126: upper roll
140: temperature sensor

Claims (5)

In the roll gap control method of the leveler for improving the flatness of the plate after rolling,
The leveler is positioned so that a plurality of upper rolls and lower rolls overlap each other vertically in a zigzag form,
obtaining the tensile strength (Ts) of the plate;
Obtaining a material width (W) representing the width of the plate;
Obtaining a material thickness (t) representing the thickness of the plate;
Obtaining a material temperature (T) by measuring the temperature of the plate in front of the leveler;
RGE representing the height difference between the lower end of the upper roll and the upper end of the lower roll at the leveler inlet according to the tensile strength, the material width, the material thickness, and the material temperature, and a height difference between the lower end of the upper roll and the upper end of the lower roll at the leveler outlet Controlling RGD representing , performing a flattening operation;
including,
In the step of performing the planarization operation,
preparing a calibration table describing the RGE and RGD according to the material temperature, the tensile strength, the material width, and the material thickness;
performing a flattening operation by controlling the RGE and RGD according to the calibration table;
including,
The step of preparing the calibration table,
grouping the material into a plurality of first groups according to a range of temperature and tensile strength;
Dividing the first group into a plurality of second groups according to a range of plate widths;
creating a table describing RGE and RGD corresponding to each of the second group and the thickness of the plate according to the range of plate thicknesses in the second group;
Roll gap control method of the leveler comprising a. delete According to claim 1,
In the calibration table, whether or not to compensate for entry to differently control the RGE at the time of entry of the leveler and the RGE after entry in each thickness range of the plate is described. According to claim 3,
When entry compensation is described in the calibration table, each of the second groups has C-RGE representing RGE when entering the leveler, and when the plate enters the leveler, it is controlled by C-RGE and entered. A method for controlling the roll gap of the leveler, which can then proceed with the flattening operation by controlling the RGE. delete

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