KR101595032B1 - Dog-bone control method in plate rolling mill - Google Patents

Abstract

According to an embodiment of the present invention, a dog-bone control method for a thick plate comprises: a step of using a length ratio obtained by dividing the length of a plate by the length of a slab, and a broadsizing ratio obtained by dividing a width of the plate by the width of the slab to obtain a target crop length; a step of substituting a predetermined value for a side crop length in equation (1), and then substituting the length ratio and the broadsizing ratio to calculate a first thickness adjustment amount of a level rolling mill when sizing, and a second thickness adjustment amount of the level rolling mill when broadsizing, where equation (1) is given by the side crop length = -α1 - (β1 × the first thickness adjustment amount) + (γ1 × the second thickness adjustment amount) - (δ1 × the length ratio ÷ the broadsizing ratio) + (ε1 × the length ratio) + (ζ1 × the broadsizing ratio) + ψ1; a step of using the first thickness adjustment amount and the second thickness adjustment amount to obtain a dog-bone crop length; a step of obtaining a crop shape value (ΔC) by subtracting the dog-bone crop length from the target crop length; and a step of performing rolling work in accordance with the first thickness adjustment amount and the second thickness adjustment amount if the crop shape value is lower than or equal to zero, and obtaining the first thickness adjustment amount and the second thickness adjustment amount again in step (b) if the crop shape value exceeds zero.

Description

[0001] DOG-BONE CONTROL METHOD IN PLATE ROLLING MILL [0002]

The present invention relates to a dogbone control method for a heavy plate, and more particularly, to a dogbone control method for a heavy plate for improving the recovery rate of the heavy plate.

Rolling is carried out by using a plasticity of a metal to pass a hot or hot metal material between two rotating rolls to form various types of materials such as plates, rods, (Shape) or the like.

Among them, the thick plate is a thick plate having a thickness equal to or more than a certain thickness, and the hot slab produced by the continuous casting process is manufactured through the rolling process. Usually, the plate rolling is controlled by the sizing phase, the broadening phase and the finishing phase to control the width, length and thickness of the plate.

Specifically, the slab discharged from the heating furnace is supplied to the rolling apparatus, and rolling is carried out to match the width, length and thickness of the finally produced thick plate.

First, the slab supplied from the heating furnace to the rolling apparatus is subjected to a sizing phase to control the flatness of the steel plate.

Next, the thick plate subjected to the roughing rolling is subjected to a broadening phase while being rotated at 90 °. Such an extrusion rolling regulates the width of the desired thick plate.

Finally, the steel plate subjected to the extrusion rolling process is rotated to 90 ° and finishing phase is performed. Such longitudinal extrusion rolling regulates the thickness of the desired thick plate.

During the rolling operation, crops appearing on the leading and trailing edges of the plate are deformed abnormally. Such a crop has a problem of decreasing the recovery rate of the heavy plate by increasing the trimming loss.

Prior Art 1: Domestic Patent Registration Bulletin 10-0423747 (March, 2003)

SUMMARY OF THE INVENTION The present invention provides a method of controlling a dogbone of a thick plate to improve the recovery rate of the heavy plate.

According to an aspect of the present invention, there is provided a method of measuring a length of a slab, the method comprising: obtaining a target crest length by using a length ratio of a length of a slab divided by a length of a slab and a width ratio of a slab divided by a width of the slab; A predetermined value is substituted for the side crop length of the equation (1), and then the length ratio and the width ratio are substituted to calculate the first thickness adjustment amount of the horizontal rolling mill and the second thickness adjustment amount of the horizontal rolling mill at the time of rough rolling step; Side length of the side-crops = -α1- (β1 × the first thickness adjustment amount) + (γ1 × the second thickness adjustment amount) - (δ1 × length ratio ÷ width ratio) + (ε1 × length ratio) + ... (1) calculating a dog bone crop length using the first thickness adjustment amount and the second thickness adjustment amount; Obtaining a crop shape value (? C) obtained by subtracting the dog bone crop length from the target crop length; And if the crop shape value is less than 0, the rolling operation is performed according to the first thickness adjustment amount and the second thickness adjustment amount, and if the crop shape value exceeds 0, the first thickness adjustment amount And a second thickness control amount of the thick plate.

In one embodiment of the present invention, the target crop length may be obtained from the equation (2). Target crest length = -τ1 + (? 1 × length ratio / width ratio ratio) + (? 1 × length ratio) + (? 1 × width ratio ratio) Equation (2)

In one embodiment of the present invention, the dog bone crop length may be obtained from the equation (3). The first thickness regulating amount) - (? 2 × the second thickness regulating amount) - (the second thickness regulating amount) - (the second thickness regulating amount) - (the second thickness regulating amount) ) + (? 2 × length ratio / width ratio ratio) + (? 2 × length ratio) + (? 2 × width ratio) +? Equation (3)

In one embodiment of the present invention,? 1 in the side-crop length calculation formula may be obtained from the calculation formula (4). the length of the slab) + (the width of the slab) + (the width of the slab) - (r1 x W / T) + Equation (4)

In one embodiment of the present invention, in the dog bone cropping length calculation formula,? 2 may be obtained from the equation (5). the length of the slab) + (the width of the slab) + (the width of the slab) - (r2 x W / T) + (5)

In one embodiment of the present invention, the side crop length value may be negative.

The effect of the dogbone control method of the heavy plate according to the present invention described above is as follows.

According to the present invention, from the simple calculation formula, the operator can reduce the generation amount of the thick plate by selectively adjusting the horizontal rolling mill.

That is, the operator can increase the recovery rate of the heavy plate by selectively controlling the first thickness control amount of the horizontal rolling mill during the rolling and the second thickness control amount of the horizontal rolling mill during the extrusion rolling to reduce the amount of the cracks generated in the heavy plate.

In addition, the operator can quickly change the work setting state of the plate mill by using a simple calculation formula used in the rolling method of the heavy plate. Therefore, the operator can quickly set the first thickness adjustment amount of the horizontal rolling mill and the second thickness adjustment amount of the horizontal rolling mill at the time of rough rolling from the results obtained through the calculation formula, thereby increasing the productivity of the heavy plate.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exemplary view showing a crop generated in a blade according to an embodiment of the present invention; FIG.
2 is a flowchart illustrating a method of controlling a dogbone of a thick plate according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "indirectly connected" . Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an exemplary view showing crop marks generated on a blade plate according to an exemplary embodiment of the present invention, and FIG. 2 is a flowchart illustrating a dog bone control method of a heavy plate according to an exemplary embodiment of the present invention.

Generally, the slab guided to the furnace through the continuous casting process is manufactured as a final product through a rolling process, a cooling process, a flattening process and a cutting process.

At this time, the slab is heated at a temperature of 1100 to 1200 ° C. When the heating temperature is lower than 1100 ° C, it is difficult to secure strength. When the temperature exceeds 1200 ° C, the grain size of the initial austenite becomes large, It can not be ensured. Therefore, the heating furnace heats the slab at a temperature of 1100 to 1200 ° C. Here, the temperature of the heating furnace is not limited to a temperature of 1100 to 1200 ° C, and it is needless to say that the manufacturer can selectively control the temperature range of the heating furnace according to the manufactured thick plate.

Next, the heated slab can be scaled down. That is, when the slab is heated for a long time in the heating furnace, scale (iron oxide that occurs on the surface) is generated on the slab surface. When the slab is processed in such a scale, the scale of the slab surface is removed through the descaling process because the product is not finished. Such a scale removal operation scales the surface of the slab by various methods such as scaling by spraying high-pressure water on the surface of the slab.

Next, the slab to which the descaling operation has been performed can be manufactured as the blade 100 through the rolling operation. That is, the rolling operation produces the blade 100 having a predetermined length, a predetermined thickness, and a constant width from the slab.

Here, the rolling operation for adjusting the size of the blade 100 is performed by changing the width, length and thickness of the blade 100 manufactured through the sizing phase, the broadening phase, and the finishing phase .

Next, the blade 100 having been subjected to the rolling operation is manufactured as a thick plate provided to the consumer through a cooling operation, a flatness operation, a cutting operation, and the like.

Here, the blade 100 having been subjected to the cooling operation and the flatness work process can be manufactured as a heavy plate through a cutting operation process. That is, the thick plate can be manufactured by cutting both ends of the blade 100 and removing the crop portion through the width cutting. The thick plate with such a cut portion removed may be cut to a certain length and supplied to the consumer. As described above, the blade 100 refers to a plate material that has undergone the rolling process, the cooling process, the flatness process, and the last step, that is, the cutting process, until the removal of the crop portion.

As for the rolling process of the thick plate, the slab supplied from the heating furnace controls the flatness of the plate 100 through a sizing phase.

Next, the blade 100, which has been subjected to the roughing and rolling, is rotated at 90 degrees and then subjected to a broadening phase. This extrusion rolling adjusts the width of the target blade 100. That is, the blade 100 rotated 90 ° with respect to the moving direction of the blade 100 may be pressed by the horizontal mill to adjust the width of the blade 100.

Finally, the blade plate 100 having undergone the extrusion rolling process is rotated in the original moving direction through a rotation of 90 占 and finishing phase is performed. Such longitudinal extrusion rolling adjusts the length and thickness of the target blade 100.

At this time, in the course of performing the above-mentioned roughing rolling, extrusion rolling, and longitudinal rolling, a crop may be generated which exhibits abnormal deformation at the front end portion, rear end portion, and both side portions of the blade 100. Such a crop increases the trimming loss and reduces the recovery of the plate.

Referring to FIG. 1, a crop may be generated in the front end portion, the rear end portion, and both side portions of the blade 100 with respect to the longitudinal direction of the blade 100 through the rolling operation. The front end portion of the blade 100 refers to a portion positioned at a front portion with respect to the traveling direction in which the blade 100 is moved and the rear end portion refers to a portion positioned at a rear portion with respect to the traveling direction in which the blade 100 is moved, The term " portion " refers to a portion located on both sides with respect to the longitudinal direction from the front end portion to the rear end portion of the blade panel 100.

FIG. 1 shows a state in which the blade is viewed from a plane (upper side), and the shape of a crop formed at the tip end and the rear end of the blade 100 is a tongue-shaped crop 105 having a tongue shape or a fish tail- (101) < / RTI >

1 (a), when the fish tail curl 101 is formed at the front end and the rear end of the blade 100, the convex side crop 102 having the convex shape on both sides of the blade 100 is formed .

Referring to FIG. 1B, when the tongue-shaped crop 105 is formed at the front end and the rear end of the blade 100, the concave side crop 106 having concave both sides of the blade 100 is formed .

As described above, in the rolling process for manufacturing the blade 100 from the slab, the pressing force is not uniformly provided to the front end portion, the rear end portion, and both side portions of the blade 100, so that an abnormal formed crop can be generated.

The crops formed on the blades 100 are removed through the cutting process. The greater the amount of the crops formed on the blades 100, the less the recovery rate of the plate is, and the productivity of the plate is lowered.

FIG. 2 is a flowchart showing a method of controlling a dogbone of a heavy plate according to an embodiment of the present invention. In the method of controlling a dogbone of a heavy plate, a first thickness control amount of a horizontal rolling mill during a high- 2 It is possible to selectively increase the thickness control amount to reduce the amount of generated cracks in the plate and to increase the productivity of the plate.

The horizontal rolling mill is configured to press the upper and lower surfaces of the blade 100 moving upward and downward with respect to the direction in which the blade 100 moves.

As described above, the rolling apparatus selectively adjusts the width ratio and the length ratio according to the rolling method of the thick plate, thereby reducing the amount of generated cracks in the blade 100 and increasing the productivity.

Specifically, the dog bone control method of the heavy plate calculates the target crop length through the size of the slab 100 discharged from the heating furnace and supplied to the rolling device. Here, the target crop length refers to the sum of the crop length generated at the tip of the blade 100, the crop length generated at the rear end of the blade 100, and the total length of the crops formed at both sides of the blade 100.

The target crest length can be obtained by the equation (2). (S100)

Target crest length = -τ1 + (? 1 × length ratio / width ratio ratio) + (? 1 × length ratio) + (? 1 × width ratio ratio) Equation (2)

(the length of the blade / the length of the slab to be introduced into the rolling apparatus), the width ratio (width of the blade plate / width of the slab to be fed into the rolling apparatus), and the target The unit of the crest length is mm]

At this time, the slab data information (such as the size and thickness of the slab) may be provided through the main control unit, the image pickup device, or the like.

The main control unit is configured to selectively control each device such as a rolling device, a cooling device, and a flatness device. The main control unit controls each device such as a rolling control unit for controlling the rolling device and a cooling control unit for controlling the cooling device Respectively.

In other words, the rolling control unit provided in the main control unit can selectively control the rolling apparatus according to the working conditions. That is, the rolling control unit can selectively control the movement of the horizontal rolling mill, the roll gap, and the like.

The main control unit stores information on the slab guided to the heating furnace through the continuous casting process. When the slab heated in the heating furnace is supplied to the rolling apparatus, the main control unit controls the slabs supplied to the rolling apparatus Thereby providing slab data information.

Meanwhile, an image pickup device may be provided between the heating furnace and the rolling device to measure the size and thickness of the slab guided to the rolling device, and various methods of measuring the size and thickness of the slab may be performed.

In this way, the manufacturer can calculate the length ratio and the extrusion ratio through the data information of the blade 100 in a state where the data information of the slab is obtained. That is, the target crop length can be obtained by substituting the length ratio and the width ratio into the above-described calculation formula (2).

Next, in the state where the value of the side crop length is predetermined, the length ratio and the width ratio of the thick plate are substituted into the calculation formula (1), and the first thickness adjustment amount of the horizontal rolling mill and the second thickness adjustment amount of the horizontal rolling mill . (S200)

Side length of the side-crops = -α1- (β1 × the first thickness adjustment amount) + (γ1 × the second thickness adjustment amount) - (δ1 × length ratio ÷ width ratio) + (ε1 × length ratio) + ... Equation (1)

(the length of the blade / the length of the slab to be introduced into the rolling apparatus), the width ratio (the width of the blade plate / the slab to be fed into the rolling apparatus), and the length , And the unit of the side crop length is mm]

At this time, the side crop length having a predetermined value is set to a negative value to adjust the side crop length. For example, the value of the side crop length can be calculated by substituting a preset value according to the size and type of the slab, the size of the manufactured heavy plate, and the like, 2 thickness adjustment amount can be selectively controlled.

At this time, a preset value assigned to the side crop length value is made to have a negative value. When the side crop length value has a negative value, the concave side crop 106 having the concave shape of the side crop shape of the blade 100 is formed. That is, the length and width of the blade 100 are adjusted by selectively adjusting the first thickness adjustment amount and the second thickness adjustment amount of the horizontal rolling mill in accordance with the side crop length value having a predetermined negative value.

On the contrary, when the side crop length values have positive values, the convex side crops 102 having convex shapes are formed on both sides of the blade 100.

At this time, the shape of the side crops = the average width of the side crops formed at the central portion of the blade, {0.5 占 (the average width of the side crops formed at the tip of the blade and the average widths of the side crops formed at the rear end of the blade) The shape of the side crop 106 or the convex side crop 102 can be grasped.

That is, in the case of the concave side crop 106, the value of the side crop is calculated as a negative value, and in the case of the convex side crop 102, the value of the side crop is calculated as a positive value.

On the other hand, in the calculation formula (1),? 1 can be calculated by substituting the width, the length of the slab, and the width and length of the blade 100 to be manufactured. That is,? 1 can be obtained through the equation (4).

the length of the slab) + (the width of the slab) + (the width of the slab) - (r1 x W / T) + Equation (4)

[s1, s2, ι1, ι2, r1 represent regression coefficients, and W / T represents (width of slab ÷ thickness of slab)

In other words, the manufacturer can obtain the value of? 1 by substituting the value of the width and length of the slab obtained from the data information of the slab and the width and length of the blade 100 to be manufactured.

As such, the side-crop length can be selectively controlled from the combination of the equation (1) and the equation (4) to the first thickness control amount of the horizontal rolling mill and the second thickness control amount of the horizontal rolling mill at the time of rough rolling.

Side length of the side-crops = -α1- (β1 × first thickness adjustment amount) + (γ1 × second thickness adjustment amount) - (δ1 × length ratio ÷ width ratio) + (ε1 × length ratio) the length of the slab) + (the width of the slab) + (the width of the slab) - (r1 x W / T) +

Next, the dog bone crop length is obtained. (S300)

The dog bone crop length can be obtained from the equation (3) through substitution of the first thickness adjustment amount and the second thickness adjustment amount of the horizontal rolling mill obtained through the calculation of the side crop length.

The first thickness regulating amount) - (? 2 × the second thickness regulating amount) - (the second thickness regulating amount) - (the second thickness regulating amount) - (the second thickness regulating amount) ) + (? 2 × length ratio / width ratio ratio) + (? 2 × length ratio) + (? 2 × width ratio) +? Equation (3)

(the length of the blade / the length of the slab charged into the rolling device), the width ratio (the length of the blade), and the width ratio Width / width of the slab charged into the rolling apparatus), and the unit of the dog bone length is mm]

Here, the regression coefficients of τ1, η1, λ1, and ρ1 are the same as the regression coefficients of τ1, η1, λ1, and ρ1 used in the target crop length of equation (2).

In this case, in the calculation formula (3),? 2 can be calculated by substituting the width, the length of the slab, and the width and length of the blade 100 to be manufactured. That is, ψ2 can be obtained through the equation (5).

the length of the slab) + (the width of the slab) + (the width of the slab) - (r2 x W / T) + (5)

[s3, s4, ι3, ι4, r2 represent regression coefficients, and W / T represents (width of slab ÷ thickness of slab)

In other words, the manufacturer can obtain the value of? 2 by substituting the values of the width and length of the slab obtained from the data information of the slab and the width and length of the blade 100 to be manufactured.

Thus, the dog bone crop length can be calculated from the combined form of equation (3) and equation (5).

The first thickness regulating amount) - (? 2 × the second thickness regulating amount) - (the second thickness regulating amount) - (the second thickness regulating amount) - (the second thickness regulating amount) ) + (? 2 × length ratio / width ratio) + (? 2 × length ratio) + (? 2 × width ratio) + (-s3 × width of slab) - (r2 × W / T) + (s4 × length of slab) + (ι3 × width of blade) + (ι4 × length of blade)

Next, the shape value of the crop (? C) is obtained. (S400)

The cog shape value (? C) is the value obtained by subtracting the dog bone length from the target cog length.

ΔC = Target Crop Length - Dogbone Crop Length

Next, it is judged whether or not the rolling operation is proceeding from the calculated value of the crop shape value? C. (S500)

If the crop shape value? C is less than or equal to '0' (when the calculated value is found to be 0 and negative (-)), the rolling control unit applies the set value of the horizontal rolling mill obtained through the above- do.

Alternatively, if the crop shape value? C is greater than zero (i.e., the calculated value is found as positive (+)), the rolling control unit commands the readjustment of the setting value of the horizontal rolling mill.

That is, when the crop shape value? C is larger than 0, the first thickness adjustment amount and the second thickness adjustment amount of the horizontal rolling mill are adjusted again from the calculation formula (1) for calculating the side crop length, The shape value? C is calculated again.

In other words, the dogbone control method of the heavy plate is performed only when the crop shape value? C finally obtained through the first thickness adjustment amount and the second thickness adjustment amount of the horizontal rolling mill is equal to or less than '0' And the rolling of the slab is performed according to the second thickness adjustment amount. (S600)

In this way, the operator can easily adjust the first thickness control amount of the horizontal rolling mill and the second thickness control amount of the horizontal rolling mill at the time of rolling to increase the recovery rate of the heavy plate by reducing the amount of the cracks generated in the heavy plate have.

It should be understood, however, that the scope of the present invention is not limited by the scope of the present invention.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

100: blade

Claims (5)

a) obtaining a target crest length by using a length ratio of the length of the blades divided by the length of the slab and a width ratio of the blades divided by the width of the slab;

b) Substituting a predetermined value into the side crop length of the equation (1), substituting the length ratio and the width ratio, the first thickness adjustment amount of the horizontal rolling mill and the second thickness adjustment amount of the horizontal rolling mill at the time of rough rolling Calculating;
Side length of the side-crops = -α1- (β1 × the first thickness adjustment amount) + (γ1 × the second thickness adjustment amount) - (δ1 × length ratio ÷ width ratio) + (ε1 × length ratio) + ... Equation (1)
(the length of the blade / the length of the slab to be introduced into the rolling apparatus), the width ratio (the width of the blade plate / the slab to be fed into the rolling apparatus), and the length Quot;

c) obtaining a dog bone crop length using the first thickness adjustment amount and the second thickness adjustment amount;

d) obtaining a crop shape value (? C) obtained by subtracting the dog bone crop length from the target crop length; And
ΔC = Target Crop Length - Dogbone Crop Length

e) If the crop shape value is less than 0, the rolling operation is performed according to the first thickness adjustment amount and the second thickness adjustment amount, and if the crop shape value exceeds 0, the first thickness The adjustment amount and the second thickness adjustment amount are obtained again,

Wherein in the step (a), the target crop length is obtained from the equation (2).

Target crest length = -τ1 + (? 1 × length ratio / width ratio ratio) + (? 1 × length ratio) + (? 1 × width ratio ratio) Equation (2)
(the length of the blade / the length of the slab to be introduced into the rolling apparatus), the width ratio (width of the blade plate / width of the slab to be fed into the rolling apparatus) is represented by the following formula:
delete The method according to claim 1,
Wherein the dog bone crop length is obtained from the equation (3) in the step (c).

The first thickness regulating amount) - (? 2 × the second thickness regulating amount) - (the second thickness regulating amount) - (the second thickness regulating amount) - (the second thickness regulating amount) ) + (? 2 × length ratio / width ratio ratio) + (? 2 × length ratio) + (? 2 × width ratio) +? Equation (3)
(the length of the blade / length of the slab to be fed into the rolling device), the width ratio (the length of the blade), and the width ratio Width of the slab inserted into the rolling apparatus)
The method according to claim 1,
Wherein in step (b),? 1 is obtained from the equation (4).

the length of the slab) + (the width of the slab) + (the width of the slab) - (r1 x W / T) + Equation (4)
[s1, s2, ι1, ι2, r1 represent regression coefficients, and W / T represents (width of slab ÷ thickness of slab)
The method of claim 3,
Wherein in step (c), the? 2 is obtained from the equation (5).

the length of the slab) + (the width of the slab) + (the width of the slab) - (r2 x W / T) + (5)
[s3, s4, ι3, ι4, r2 represent regression coefficients, and W / T represents (width of slab ÷ thickness of slab)

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