JPH05237528A - Camber control method in metal rolling - Google Patents

Abstract

PURPOSE:To surely control the camber without providing plate thickness differences between right and left by reducing the friction factor in the external side region of a metal cambered by a friction factor adjustment means when a camber is produced in the metal. CONSTITUTION:On the basis of the lubrication condition required for correcting the camber, the lubrication oil of the selected kind is supplied from a nozzle 10a located in the specified width direction between a metal 1 and a work roll 2 by a rolling oil supplying device 9 and a width direction part lubrication oil supplying device 10, and adjustment is executed so that the friction factor between the external region of the metal and work roll 2 of the rolling mill 3A may be reduced. Thus, when a camber is produced in the metal 1 while the metal 1 is rolled in the condition where the movement in the width direction of the metal is restricted on the inlet side of the rolling mill 3B, the external region of the metal 1 is adjusted so that the friction factor between the work roll of the rolling mill 3B may be reduced, leading to the control of the camber of the metal 1 with good precision.

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 metallic material during rolling of the metallic material.

[0002]

2. Description of the Related Art It is generally known that the basic concept of camber control in rolling is that the difference between the left and right rolling reductions and the difference between the left and right elongations have a fixed relationship. As a camber control means based on this idea, for example, as disclosed in Japanese Patent Laid-Open No. 61-269914, the camber of a metal material before rolling is measured, and the camber after rolling is eliminated from the measurement result. Calculate the plate thickness difference required for
There is one that corrects the camber by adjusting the left and right rolling positions.

[0003]

However, when the cause of the camber is a left-right plate thickness difference of the rolling mill such as a left-right rolling position difference, it is appropriate to control the camber by the above-mentioned conventional means. Although it is conceivable, when only the camber is generated without causing the left and right plate thickness difference, the above-mentioned conventional means causes the left and right plate thickness difference to the contrary, and the next process of the continuous process line is performed. This may cause troubles or poor plate thickness accuracy in response to the user's demands for which the plate thickness accuracy in the width direction becomes severe.

FIG. 11 shows the measurement results of the difference between the left and right plate thicknesses of the material (wedge amount) and the camber (the center line profile in the width direction of the material) in which troubles due to the camber occurred in the actual rolling after the rolling. There is almost no difference between the left and right plate thicknesses, or the drive side (DS) tends to be slightly thicker, but the camber is bent on the working side (WS). Regarding the phenomenon that only the camber occurs without causing the difference between the left and right plate thickness, it has been sensuously said that there is an influence of the rough surface of the roll, but it cannot be explained in the above-mentioned way of thinking. behavior,
The mechanism has never been specified.

The present invention is intended to solve such a problem, and in the case where only a camber is generated without causing a difference in plate thickness between left and right, the left and right rolling positions of the rolling mill are not changed, that is, the left and right rolling positions are changed. An object of the present invention is to provide a method for controlling a camber in rolling a metal material, which can surely control the camber without making a difference in plate thickness.

[0006]

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

Further, the friction coefficient adjusting means is composed of a plurality of nozzles for supplying lubricating oil between the work roll and the metal material, and the plurality of nozzles are provided on the inlet side of the rolling mill. It may be installed along the width direction of the metal material (Claim 2), and the friction coefficient adjusting means adjusts 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 provided, and the plurality of grinders may be installed along the width direction of the metal material (claim 3).

[0008]

According to the camber control method for metal material rolling of the present invention described above (Claim 1), when rolling the metal material while restraining the movement of the metal material in the width direction on the entrance 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.

Further, 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 selected. The friction coefficient between them is appropriately adjusted.

Further, in the method of claim 3, 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 cancel the cambered metal. The coefficient of friction between the outer region of the material and the work rolls of the rolling mill is adjusted accordingly.

[0011]

First, the principle of the method of the present invention will be described before the description of the embodiments of the present invention. As described above, the conventional thinking is that the difference between the left and right rolling reduction rates and the difference between the left and right elongation rates have a fixed relationship. FIG. 5 shows the relationship between the left and right rolled position difference and the camber. The width expansion in rolling only considers the relaxation rate due to the lateral flow of the material, and further has a small effect on the camber. 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, when a camber occurs, the difference between the left and right plate thicknesses (wedges) as shown in the middle and upper stages of FIG. ) Was also thought to occur at the same time. This deformation behavior could not explain the phenomenon of camber generation without the difference in plate thickness between left and right due to the rough surface of the roll.

Therefore, the present inventors have accumulated a number of experimental investigations and have obtained new knowledge about the relationship between the rough surface of the roll and the camber. That is, this is a phenomenon in which a camber is generated due to the difference in width expansion amount at each position in the material width direction. This is simply to explain the phenomenon that only the camber occurs without causing the left and right plate thickness difference that could not be explained by the conventional thinking. This phenomenon is 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 regions 1a and 1b of the material 1 before rolling are considered with the plate width center as a boundary. Figure 6
As shown in (b), assuming that the materials 1 are left and right individually, when the width expansion amounts W ₁ and W ₂ are different, the material length obtained by rolling is the one having the smaller width expansion (in the figure, W ₁ < Sign 1 for W ₂
a side) becomes longer. Actually, the metal material 1 is shown in FIG.
Since it is a continuous body as shown in (3) and is not individually stretched in the width direction, rolling causes a camber having no difference in left and right plate thickness.

The relationship between the width expansion amount and the camber can be formulated as follows. In the following formula, 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 law of constant volume in rolling, and (2)
Equation (3) represents the camber curvature, and Equation (3) represents the camber curvature.

[0015]

[Equation 1]

Here, 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, and κ. Is the camber curvature, ρ is the radius of curvature, and Ψ is the width expansion ratio.

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

[0018]

[Equation 2]

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

By the way, the present inventors have confirmed by experiments that the width expansion ratio Ψ can be easily changed by the friction coefficient. The degree of influence on the width spread rate Ψ is shown in FIGS.
Shown in. Here, the smaller the friction coefficient is, the better the lubricity is, and the neutral point is closer to the exit side of the work roll 2 due to 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 to each other. In other words, the smaller the coefficient of friction is, the larger the range in which the plate speed is slower than the peripheral speed of the roll, that is, the so-called reverse travel area, and the slower the speed of the material 1 on the entrance side of the work roll 2.

When the friction coefficient differs in the width direction, the smaller the friction coefficient is, the smaller the speed of the material 1 on the entrance side of the work roll 2 is. Therefore, although the material 1 tends to rotate, normally, the lateral movement of the material 1 is restricted by an edger roll, a side guide, or the like on the entrance side. Thereby, a stress distribution in the rolling direction occurs at each position in the width direction of the material 1. This rolling direction stress distribution has a great influence on the width expansion ratio Ψ, that is, in the case of the indentation stress state, the width expansion ratio Ψ becomes large,
In the tensile stress state, the width expansion ratio Ψ becomes small.

FIG. 7 is a graph showing the relation between the camber and the wedge when the surface roughness of the work roll is changed between the left and right. As shown in FIG. 7, the surface roughness of the work roll is If they are different, the left and right width expansion ratios of the plate materials are different. As a result, even if the difference between the left and right plate thicknesses is zero, a large camber occurs with the smooth side of the work roll inside. Further, it can be seen that the larger the roll roughness difference, the smaller the inclination of the straight line in FIG. 7 and the smaller the camber correction effect by the adjustment of the left and right rolling positions. 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 camber and the difference between the lateral spread ratios when lubricating oil is supplied to one side portion corresponding to 1/4 to 1/2 of the strip width and rolled. Figure 8
As is clear from the result shown in (1), changing the lubrication portion along the width direction also has the same effect as in the case of the difference in roll roughness.

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

A camber control method in metal material rolling as an embodiment of the present invention will be described below 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. A front view showing the configuration of a widthwise partial lubricating oil supply device as a friction coefficient adjusting means,
FIG. 3 is a flow chart for explaining the operation of the apparatus of this embodiment.

As shown in FIG. 1, 1 is a rolling mill 3A, 3B.
Metal material to be rolled by 2; a pair of upper and lower work rolls provided for each rolling mill 3A, 3B; 4 a rolling mill 3
Side guides 5 provided on the entrance sides of A and 3B for restraining the movement of the metal material 1 in the width direction, and 5 are plate thickness gauges for measuring the width direction plate thickness of the metal material 1 rolled by the rolling mills 3A and 3B, A camber gauge 6 measures the camber of the metal material 1 rolled by each of the rolling mills 3A and 3B.

And, 7 is a plate thickness gauge 5 and a camber gauge 6
Based on the data from the above, the camber / plate thickness difference calculation device for calculating the camber and left / right plate thickness difference (wedge amount) of the metal material 1 on the output side of the rolling mill 3A, 8 is the calculation result of the camber / plate thickness difference calculation device 7. And the rolling conditions (thickness, width, temperature, etc.) are used to calculate the camber curvature and wedge ratio of the metal material 1, and the camber curvature component that does not depend on the left and right plate thickness difference is calculated to provide the lubrication necessary for camber correction A control calculation device for obtaining conditions (lubricant, lubrication width), 9 is a rolling oil supply device for supplying rolling oil (lubrication oil) based on the lubrication condition from the control calculation device 8, and 10 is rolled by the rolling mill 3B. Widthwise partial lubricating oil supply device capable of adjusting the friction coefficient between the outer region of the metallic 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 comprises a plurality of (11 in FIG. 2, upper and lower) supplying lubricating oil between the work roll 2 and the metal material 1. It is composed of nozzles 10a, and these nozzles 10a are installed along the width direction of the metal material 1 on the entrance side of the rolling mill 3B. When a camber occurs in the metal material, the control arithmetic unit 8 selects the type of lubricating oil to be supplied from the nozzle 10a in the widthwise partial lubricating oil supply device 10 and the selection of the nozzle 10a to which the lubricating oil should be supplied. 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 in accordance with the calculation result of

The operation of the apparatus configured as described above will be described with reference to the flowchart shown in FIG.
The plate thickness gauge 5 and the camber gauge 6 measure the width direction plate thickness and the camber of the metal material 1 rolled by the rolling mill 3A, and based on the measurement results, the camber / plate thickness difference calculation device 8 performs rolling. Material 1 on the exit side of machine 3A
Calculate the camber and the thickness difference (wedge amount) between left and right
(Step S1).

Then, the control calculation device 8 receives the calculation result of the camber / plate thickness difference calculation device 7 and reads the rolling conditions (plate thickness, plate 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 left and right plate thickness difference.
(Step S4), from the measured camber curvature, the average width expansion ratio necessary for correcting the camber is shown in FIGS.
The lubrication condition (lubricant, lubrication width) required for camber correction is obtained from the data shown in (step S5).

The lubrication condition calculated in this way is output to the rolling oil supply device 9 (step S6), and selected by the rolling oil supply device 9 and the widthwise partial lubrication oil supply device 10 based on the lubrication condition. The specified type of lubricant 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 becomes small. Is adjusted.

As described above, according to the camber control method of this embodiment, when the metal material 1 is rolled while the movement of the metal material 1 in the width direction is restrained on the entrance side of the rolling mill 3B, When camber occurs in the metal material 1,
The coefficient of friction between the outer region of the metal material 1 and the work rolls 2 of the rolling mill 3B is adjusted to be small, and in the metal material rolling, there is no difference between the left and right plate thicknesses of the metal material 1. Since you can control the camber with high precision,
Rolling troubles in the rolling process can be significantly reduced,
It greatly contributes to the improvement of product quality.

Here, FIG. 10 shows a case where the lubricant A is applied to a metal material having a camber amount of less than 40 mm in an area of 1/2 of the plate width on the outside of the bend and rolling is performed before and after rolling. 11 is a graph showing the amount of camber, and as is clear from FIG. 10, it was confirmed that the amount of camber after rolling was reduced to 5 mm and the control effect was large by applying the method of the present invention.

Further, FIG. 10 shows the camber amount when the method of the present invention is applied in comparison with the conventional method for each number of rollings. As is apparent from FIG. 10, once the camber has once occurred, a large camber has occurred subsequently, but in the case of the method of the present invention, it is about 50 times larger than that of the conventional method.
It was confirmed that the camber amount was reduced by%.

In the above embodiment, the case where the widthwise partial lubricating oil supply device 10 is used as the friction coefficient adjusting means has been described, but a work roll surface roughness adjusting device 11 as shown in FIG. 4 is used. Good. The work roll surface roughness adjusting device 11 is, as shown in FIG. 4, a work roll 2 of the rolling mill 3B at an arbitrary position in the width direction of the metal material 1.
It is composed of a plurality of grinders 11a for adjusting the surface roughness of the grinders (upper and lower in FIG. 4).
1a is installed along the width direction of the metal material 1 and is configured.

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

[0037]

As described above in detail, according to the camber control method for rolling a metal material of the present invention, the rolling of the metal material is performed while restraining the movement of the metal material in the width direction on the entrance side of the rolling mill. When a camber occurs in the metal material during rolling, by adjusting so as to reduce the friction coefficient between the outer region of the cambered metal material and the work roll of the rolling mill, in the metal material rolling, There is an effect that the camber of the metal material can be accurately controlled without making a difference between left and right plate thicknesses, rolling troubles in the rolling process can be significantly reduced, and product quality can be significantly improved.

[Brief description of drawings]

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

FIG. 2 is a front view showing a configuration of a widthwise partial lubricating oil supply device as friction coefficient adjusting means in the present embodiment.

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

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

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

FIGS. 6A to 6C are perspective views for explaining the principle of camber generation due to the left-right difference in width expansion ratio.

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

FIG. 8 is a graph showing the relationship between the camber and the difference in the lateral spread ratio when the lubricating oil is supplied to one side portion corresponding to 1/4 to 1/2 of the plate width and rolled.

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

FIG. 10 is a graph showing the amount of camber 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 measurement results of a wedge amount of a material and a widthwise centerline profile of the material in which troubles due to a camber occurred after rolling in actual rolling.

[Explanation of symbols]

1 Metal Material 2 Work Rolls 3A, 3B Rolling Machine 4 Side Guide 5 Plate Thickness Meter 6 Camber Meter 7 Camber / Plate Thickness Difference Calculator 8 Control Calculator 9 Rolling Oil Supply Device 10 Width Partial Lubricating Oil Supply Device (Friction Coefficient Adjustment) Means) 10a Nozzle 11 Work roll surface roughness adjusting device (friction coefficient adjusting means) 11a Grinder

Claims (3)

[Claims] 1. A friction coefficient adjusting means capable of adjusting a friction coefficient between a metal material rolled by a rolling mill and a work roll in the rolling mill is provided, and a width of the metallic material is provided on an entrance side of the rolling mill. When the movement of the metal material is restricted by the rolling motion and a camber occurs in the metal material when the metal material is rolled by the rolling mill, the friction coefficient adjusting means reduces the friction coefficient of the outer region of the metal material. A method for controlling a camber in rolling of a metal material, characterized in that 2. The friction coefficient adjusting means comprises a plurality of nozzles for supplying lubricating oil between the work roll and the metal material, and the plurality of nozzles are provided on the rolling mill entrance side, The camber control method in metal material rolling according to claim 1, wherein the camber control method is installed along the width direction of the metal material. 3. The friction coefficient adjusting means is composed of a plurality of grinders for adjusting the surface roughness of the work roll at an arbitrary position in the width direction of the metal material, and the plurality of grinders are the metal grinders. The camber control method for rolling a metal material according to claim 1 or 2, wherein the method is provided along the width direction of the material.