JP2786771B2 - Camber control method in metal rolling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing and controlling camber generated in a metal material during rolling of the metal material.

[0002]

2. Description of the Related Art It is generally known that a basic concept of camber control in rolling is that a difference between a right and left rolling reduction rate and a right and left elongation rate difference have a fixed relationship. As a camber control means based on this concept, for example, as disclosed in JP-A-61-269914, to measure the camber of a metal material before rolling, and to eliminate the camber after rolling from the measurement result. Calculate the thickness difference required for
There is one that corrects the camber by adjusting the right and left rolling position.

[0003]

However, if the cause of the camber is a difference between the left and right plate thicknesses, such as a difference in the horizontal rolling position of the rolling mill, it is appropriate to control the camber by the above conventional means. It is conceivable that, when only the camber is generated without a difference in the thickness of the left and right plates, the above-described conventional means causes a difference in the thickness of the left and right plates, and consequently, in the next step of the process line that has been advanced. It becomes a cause of poor plate thickness accuracy in response to troubles and demands of users whose plate thickness accuracy in the width direction has become strict.

[0004] Fig. 11 shows the measurement results of the difference between the left and right plate thicknesses (wedge amount) and the camber (the widthwise center line profile of the material) of the material in which trouble has occurred due to the camber after rolling in actual rolling. There is little difference between left and right plate thicknesses or the drive side (DS) tends to be slightly thicker, but the camber is bent on the work side (WS). Until now, the phenomenon that only the camber has occurred without causing a difference in the thickness of the left and right plates has been intuitively said to be affected by the roll surface roughness, etc. behavior,
The mechanism was never specified.

The present invention is intended to solve such a problem. In a case where only a camber is generated without a difference between left and right plate thicknesses, the left and right rolling position of the rolling mill is not changed, that is, the left and right rolling positions are not changed. An object of the present invention is to provide a camber control method in metal material rolling, in which a camber can be reliably controlled without giving a difference in sheet thickness.

[0006]

In order to achieve the above object, a camber control method for rolling a metal material according to the present invention comprises a method of controlling a friction coefficient between a metal material rolled by a rolling mill and a work roll in the rolling mill. And a friction coefficient adjusting means capable of adjusting the width of the metal material on the entry side of the rolling mill in the width direction of the metal material, and when the metal material is cambered during rolling of the metal material by the rolling mill, Is characterized in that the friction coefficient adjusting means adjusts the friction coefficient in the outer region of the cambered metal material to be small.

Further, the friction coefficient adjusting means comprises a plurality of nozzles for supplying lubricating oil between the work roll and the metal material. The metal roll may be installed along the width direction of the metal material (claim 2), and the friction coefficient adjusting means may adjust the surface roughness of the work roll at an arbitrary position in the width direction of the metal material. A plurality of grinders may be installed along the width direction of the metal material.

[0008]

According to the above-described camber control method in the rolling of the metal material of the present invention (claim 1), when the metal material is rolled while restricting the movement of the metal material in the width direction on the entry side of the rolling mill, When camber occurs in the metal material, the friction coefficient adjusting means adjusts the friction coefficient between the outer region of the cambered metal material and the work roll of the rolling mill to be small.

In the method of claim 2, the friction coefficient adjusting means selects the type of the lubricating oil and the nozzle for supplying the lubricating oil so that the outer region of the cambered metal material and the work roll of the rolling mill are connected. The friction coefficient between them is appropriately adjusted.

Further, in the method according to the third aspect, the friction coefficient adjusting means selects a grinder at an appropriate position in the width direction of the metal material and adjusts the surface roughness of the work roll by the grinder to thereby adjust the cambered metal. The coefficient of friction between the outer region of the material and the work roll of the rolling mill is adjusted accordingly.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing embodiments of the present invention, the principle of the method of the present invention will be described. As described above, according to the conventional thinking, the difference between the right and left rolling reduction rates and the difference between the left and right elongation rates have a certain relationship. FIG. 5 shows the relationship between the left and right rolling position difference and the camber. The width expansion in rolling is based only on the consideration of the relaxation rate due to the lateral flow of the material, and furthermore, the influence on the camber is small. Therefore, as shown in FIG. 5, when a straight material 1 having a rectangular cross section is rolled by the work rolls 2 and 2 and a camber is generated, as shown in the middle and upper sections of FIG. ) Was also thought to occur at the same time. This deformation behavior could not explain the phenomenon of camber generation without a difference in thickness between the left and right plates due to roll surface roughness.

Therefore, the present inventors have accumulated experimental investigations and have obtained new knowledge on the relationship between roll surface roughness and camber. That is, camber is generated due to a difference in the width spread amount at each position in the material width direction. This simply explains the phenomenon that only the camber occurs without causing a difference between the left and right plate thicknesses, which cannot be explained by the conventional thinking. This phenomenon forms the basis of the present invention and will be described in detail below.

FIG. 6 schematically shows the above-mentioned phenomenon. As shown in FIG. 6A, the left and right two regions 1a and 1b of the material 1 before rolling are considered at the center of the plate width. FIG.
As shown in (b), assuming that the material 1 is individual on the left and right, if the width spread amounts W ₁ and W ₂ are different, the material length by rolling is smaller in width (W ₁ <in the figure). sign in W ₂ 1
a side) becomes longer. Actually, the metal material 1 is as shown in FIG.
Since the continuous body is not stretched individually in the width direction, a camber having no difference in thickness between left and right plates is generated by rolling.

The relationship between the width and the camber can be formulated as follows. In the following formulas, the subscripts W and D represent the left and right ends of the material 1, that is, the working side and the driving side, respectively. Equation (1) is derived from the constant volume law in rolling, and (2)
The equation represents the width spread rate, and the equation (3) represents the camber curvature.

[0015]

(Equation 1)

Where H is the thickness before rolling, h is the thickness after rolling, W ₀ is the width before rolling, W is the width after rolling, L is the length before rolling, l is the length after rolling, κ Is the camber curvature, ρ is the radius of curvature, and Ψ is the width spread rate.

When the equations (1) and (2) are substituted into the equation (3), the relationship between the width expansion ratio Ψ and the camber curvature κ is expressed by the following expression (4).

[0018]

(Equation 2)

Here, Ψ _W and Ψ _D represent the width expansion ratio at the left and right ends of the material 1, respectively.

By the way, the present inventors have confirmed through experiments that the width expansion ratio Ψ can be easily changed by the friction coefficient. 7 to 9 show the degree of influence on the width spread rate Ψ.
Shown in Here, the smaller the friction coefficient, the better the lubricity, and the neutral point is closer to the exit side of the work roll 2 by the balance formula of the rolling direction force between the work roll 2 and the material 1 in rolling. Become. Here, the neutral point is a position where the roll peripheral speed and the plate speed are equal. In other words, as the coefficient of friction is smaller, the range in which the plate speed is lower than the roll peripheral speed, the so-called reverse range, becomes larger, and the speed of the material 1 on the entry side of the work roll 2 becomes lower.

When the friction coefficient is different in the width direction, the speed of the material 1 on the entry side of the work roll 2 is smaller when the friction coefficient is smaller than when the friction coefficient is larger. Therefore, the material 1 is likely to rotate, but the movement of the material 1 in the lateral direction is usually restricted by an edger roll, a side guide, or the like on the entry side. As a result, a stress distribution in the rolling direction occurs at each position in the width direction of the material 1. This rolling direction stress distribution greatly affects the width expansion rate 広 が り, that is, in the case of the indentation stress state, the width expansion rate 大 き く increases,
In the case of a tensile stress state, the width expansion ratio Ψ becomes small.

FIG. 7 is a graph showing the relationship between the camber and the wedge when rolling is performed while changing the surface roughness of the work roll from left to right. As shown in FIG. If they are different, as a result of the left and right width spreading ratios of the plate materials being different, even when the difference between the left and right plate thicknesses is zero, a large camber is generated with the smooth side of the work roll inside. Further, it can be seen that as the roll roughness difference increases, the inclination of the straight line in FIG. 7 decreases, and the camber correction effect by adjusting the right and left pressing positions decreases. This indicates that the larger the coefficient of friction, the greater the effect of the present invention.

FIG. 8 is a graph showing the relationship between the difference in the lateral width spread ratio and the camber when the lubricating oil is supplied to one side portion corresponding to 側 to の of the plate width and rolled. FIG.
As can be seen from the results shown in FIG. 5, the same effect as in the case of the difference in roll roughness can be obtained by changing the lubricated portion along the width direction.

Therefore, in the camber control method according to the present invention, the width expansion ratio required for correcting the camber is determined from the measured camber curvature, and the rolling lubricating oil conditions and the roll surface roughness are determined.

Hereinafter, a camber control method in the rolling of metal material as one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an apparatus to which the present method is applied, and FIG. Front view showing the configuration of the width direction partial lubricating oil supply device as friction coefficient adjusting means,
FIG. 3 is a flowchart for explaining the operation of the apparatus of the present embodiment.

As shown in FIG. 1, 1 is a rolling mill 3A, 3B
2 is a pair of upper and lower work rolls provided in each rolling mill 3A, 3B, and 4 is each rolling mill 3
A side guide provided on the entrance side of A, 3B for restraining the movement of the metal material 1 in the width direction; 5 is a thickness gauge for measuring the width direction thickness of the metal material 1 rolled by each of the rolling mills 3A, 3B; Reference numeral 6 denotes a camber meter for measuring the camber of the metal material 1 rolled by each of the rolling mills 3A and 3B.

7 is a thickness gauge 5 and a camber gauge 6
Camber / thickness difference calculating device for calculating the camber and left / right plate thickness difference (wedge amount) of the metal material 1 on the exit side of the rolling mill 3A based on the data from the first and second rolling mills 3; The camber curvature and wedge ratio of the metal material 1 are calculated based on the rolling conditions (sheet thickness, sheet width, temperature, etc.), and the camber curvature component independent of the difference between the left and right sheet thicknesses is calculated to provide lubrication necessary for camber correction. A control arithmetic unit 9 for obtaining conditions (lubricant, lubrication width), a rolling oil supply unit 9 for supplying rolling oil (lubricating oil) based on the lubrication conditions from the control arithmetic unit 8, and a rolling oil supply unit 10 Width direction partial lubricating oil supply device capable of adjusting the friction coefficient between the outer region of the metal material 1 and the work roll 2 in the rolling mill 3B
(Friction coefficient adjusting means).

As shown in FIG. 2, the widthwise partial lubricating oil supply device 10 includes a plurality (11 in FIG. 2) of supplying lubricating oil between the work roll 2 and the metal material 1. The nozzle 10a is configured to be installed along the width direction of the metal material 1 on the entry side of the rolling mill 3B. When the camber occurs in the metal material, the selection of the type of the lubricating oil to be supplied from the nozzle 10a and the selection of the nozzle 10a to which the lubricating oil is to be supplied in the width direction partial lubricating oil supplying device 10 are controlled by the control arithmetic unit 8 According to the calculation result of the above, the rolling oil supply device 9 is configured to reduce the friction coefficient between the outer region of the cambered metal material 1 and the work roll 2 of the rolling mill 3B.

The operation of the apparatus configured as described above will be described with reference to the flowchart shown in FIG.
The thickness in the width direction and the camber of the metal material 1 rolled by the rolling mill 3A are measured by the thickness gauge 5 and the camber meter 6, respectively. Material 1 on the exit side of machine 3A
Of the camber and left and right plate thickness difference (wedge amount)
(Step S1).

Then, the control calculation device 8 receives the calculation result of the camber / thickness difference calculation device 7 and reads the rolling conditions (thickness, width, temperature, etc.) (step S).
2) Based on these data, the camber curvature and wedge ratio of the metal material 1 are calculated (step S3). Furthermore, calculate the camber curvature component that does not depend on the difference between the left and right plate thicknesses.
(Step S4) From the measured camber curvature, the average width spread rate necessary for correcting the camber is shown in FIGS.
The lubrication conditions (lubricant, lubrication width) required for camber correction are obtained from the data as shown in (5) (step S5).

The lubrication conditions calculated in this way are output to the rolling oil supply device 9 (step S6), and are selected by the rolling oil supply device 9 and the width direction partial lubrication oil supply device 10 based on the lubrication conditions. Is supplied between the metal material 1 and the work roll 2 from the nozzle 10a at the predetermined width direction position, and the coefficient of friction between the outer region of the metal material and the work roll of the rolling mill decreases. Is adjusted as follows.

As described above, according to the camber control method of the present embodiment, when the metal material 1 is being rolled while the movement in the width direction of the metal material 1 is restricted on the entrance side of the rolling mill 3B, When camber occurs in the metal material 1,
The friction coefficient between the outer region of the metal material 1 and the work roll 2 of the rolling mill 3B is adjusted so as to be small. Since the camber can be controlled accurately,
Rolling trouble in the rolling process can be significantly reduced,
It greatly contributes to the improvement of product quality.

Here, FIG. 10 shows before and after rolling when a lubricant A is applied to a metal material having a camber amount of less than 40 mm in a region of a half of the plate width outside the bend and rolled. FIG. 10 is a graph showing the camber amount. As is apparent from FIG. 10, it was confirmed that the camber amount after rolling was reduced to 5 mm and the control effect was large by applying the method of the present invention.

FIG. 10 shows the camber amount when the method of the present invention is applied in comparison with the conventional method for each rolling number. As is apparent from FIG. 10, once a camber has been generated once, a large camber has been continuously generated. However, in the case of the method of the present invention, it is about 50 times smaller than that of the conventional method.
It was confirmed that the camber amount was reduced by%.

In the above embodiment, the case where the width direction partial lubricating oil supply device 10 is used as the friction coefficient adjusting means has been described, but the work roll surface roughness adjusting device 11 as shown in FIG. Is also good. As shown in FIG. 4, the work roll surface roughness adjusting device 11 is a work roll 2 of a rolling mill 3 </ b> B at an arbitrary position in the width direction of the metal material 1.
A plurality of grinders 11a each for adjusting the surface roughness of the grinder 11 (upper and lower in FIG. 4) are provided.
1 a is provided along the width direction of the metal material 1.

By using such a work roll surface roughness adjusting device 11 to adjust the friction coefficient based on the data as shown in FIGS. 7 and 9, the same operation and effect as in the above embodiment can be obtained. can get. In addition, the width direction partial lubricating oil supply device 10 and the work roll surface roughness adjusting device 11 may be used in combination as friction coefficient adjusting means.

[0037]

As described above in detail, according to the camber control method in the rolling of the metal material of the present invention, the rolling of the metal material is performed in a state where the movement of the metal material in the width direction is restricted on the entry side of the rolling mill. When the metal material is cambered, by adjusting the coefficient of friction between the outer region of the cambered metal material and the work roll of the rolling mill in the rolling of the metal material, The camber of the metal material can be accurately controlled without making a difference between the left and right plate thicknesses, so that the rolling trouble in the rolling process can be significantly reduced and the product quality can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an apparatus to which a camber control method in metal material rolling as one embodiment of the present invention is applied.

FIG. 2 is a front view showing a configuration of a width direction partial lubricating oil supply device as a friction coefficient adjusting unit in the embodiment.

FIG. 3 is a flowchart for explaining the operation of the apparatus of the present embodiment.

FIG. 4 is a front view showing a configuration of a work roll surface roughness adjusting device as a friction coefficient adjusting unit in the present embodiment.

FIG. 5 is a schematic diagram for explaining a relationship between a left and right rolling position difference and a camber.

6 (a) to 6 (c) are perspective views for explaining the principle of camber generation due to the difference in width between the right and left sides.

FIG. 7 is a graph showing a relationship between a camber and a wedge when rolling is performed while changing the surface roughness of a work roll between left and right.

FIG. 8 is a graph showing the relationship between camber and the difference between the right and left width spread ratios when lubricating oil is supplied to one side portion corresponding to １ ／ to 板 of the plate width and rolled.

FIG. 9 is a graph showing specific camber control effects when the method of the present invention is applied to actual camber control.

FIG. 10 is a graph showing the camber amount when the method of the present invention is applied, in comparison with the conventional method for each rolling number.

FIG. 11 is a graph showing a measurement result of a wedge amount and a widthwise centerline profile of a material in which trouble due to a camber occurs after rolling in actual rolling.

[Explanation of symbols]

Reference Signs List 1 metal material 2 work roll 3A, 3B rolling mill 4 side guide 5 thickness gauge 6 camber meter 7 camber / thickness difference calculation device 8 control calculation device 9 rolling oil supply device 10 width direction partial lubrication oil supply device (friction coefficient adjustment Means) 10a Nozzle 11 Work roll surface roughness adjusting device (friction coefficient adjusting means) 11a Grinder

Continuation of the front page (56) References JP-A-60-250818 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21B 37/28-37/44

Claims (3)

(57) [Claims] A friction coefficient adjusting means for adjusting a friction coefficient between a metal material to be rolled by a rolling mill and a work roll in the rolling mill; and a width of the metal material on the entrance side of the rolling mill. When the movement in the direction is constrained and camber occurs in the metal material during rolling of the metal material by the rolling mill, the coefficient of friction in the outer region of the cambered metal material is reduced by the friction coefficient adjusting means. A method for controlling camber in metal material rolling, characterized in that the method is adjusted to: 2. The friction coefficient adjusting means comprises a plurality of nozzles for supplying lubricating oil between the work roll and a metal material, wherein the plurality of nozzles are provided on the rolling mill entrance side. The camber control method according to claim 1, wherein the camber is installed along a width direction of the metal material. 3. The friction coefficient adjusting means includes a plurality of grinders for adjusting a surface roughness of the work roll at an arbitrary position in a width direction of the metal material, and the plurality of grinders are provided on the metal material. The camber control method according to claim 1 or 2, wherein the camber is installed along the width direction of the material.