JPH01205820A - Method for straightening camber of metallic plate - Google Patents

Abstract

PURPOSE:To effectively straighten camber by changing the quantity of indentation of a leveler roller in the width direction and giving a difference to the quantity of elongation of the metallic plate in the width direction. CONSTITUTION:In accordance with a radius of curvature of camber generated by rolling, the hydraulic pressure of right and left hydraulic rolling reduction devices 5, 5' in the width direction is changed respectively and the quantity of indentation of the roller leveler is controlled so that a field of stress most suitable to straighten the camber is formed is the width direction on the metallic plate 1. Besides, for a metallic plate provided with an unstable curvature of the camber, too, the camber can be straightened by controlling the hydraulic rolling reduction devices 5, 5' so that the quantity of indentation of the roller leveler is proportional to its curvature.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for correcting camber (lateral bending) of a metal plate.

<Conventional technology> In rolling metal plates such as steel plates, the biting position of the rolled material in the rolling mill is caused by various factors such as differences in deformation resistance in the width direction of the material to be rolled and differences in the left and right rigidity of the rolling mill. There is a problem in that the material to be rolled is curved in the width direction due to the phenomenon of deviation in the direction, resulting in camber.

When camber occurs, as shown in Figure 7,
In the camber-generated portion of the rolled material 1, the predetermined dimensions of the plate A cannot be obtained, resulting in a decrease in product yield.

Conventionally, as a measure against the occurrence of camber, camber control has been carried out by controlling the difference in opening between the left and right rolls of a rolling mill (see, for example, Japanese Patent Laid-Open No. 159911/1983).

<Problems to be Solved by the Invention> However, the above camber control method has not been able to provide sufficient control effects because heat crown, roll wear, etc. occur as disturbances as rolling progresses. Furthermore, no method of correcting camber after rolling has been implemented at present.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for effectively correcting camber generated in a rolled material.

<Means for solving IIS> The present invention, when correcting the flatness of a metal plate using a roller leveler, changes the leveler roller pushing amount in the width direction to make a difference in the amount of elongation of the metal plate in the width direction. The camber of the metal plate is corrected by giving the following.

Effect> As shown in Fig. 1, the camber produced by rolling has a radius of curvature ρ. It is a bend.

The strain caused in the steel plate at the edge in the width direction due to this bending is
When the plate width is W, elongation side: εr −w / 2ρ, ・・・−・・・
−・−・−(1) Shrinkage side: εz −−W / 2ρ,
・−・−・・・−・・・−・(2).

Figure 2 shows how the camber can be adjusted by the roller leveler of the present invention.
1 is an explanatory diagram of a method for correcting, where l indicates a metal plate, 2 indicates a leveler roller, e III indicates the interval between the upper and lower leveler rollers after pushing the leveler roller on the elongation side,
h8 is the top after pushing the leveler roller on the shrinking side,
This is the distance between the lower leveler rollers.

When hl and h8 are changed as shown in the figure, the stress distribution in the width direction of the metal plate l becomes as shown in Figure 3, a width direction stress field is formed, and the stress at the width direction ends of the metal plate 1 is If Young's modulus is E, elongation side: σ+−Eε, ...−・−Curve 1・
・(3) Contraction side: σ, = Et, ...
−・−・・−・・−・(4).

On the other hand, as shown in FIG.
A stress field in the plate thickness direction is formed, and the above-mentioned width direction stress is applied to this state. In FIG. 4, σ is the yield stress.

Figure 5 shows the internal strain change at the plate end (shrinking side) at this time, and the widthwise stress σ! shown in Figure 3 above! (Tension), the steel plate 1 receives a tensile strain of Δε8. Here, εa is the yield strain caused by the yield stress σ shown in FIG. 4, and t is the plate thickness. Similarly, the elongated end portion also receives a compressive strain of Δε1.

This results in a radius of curvature ρ due to rolling. camber of
The metal plate 1 where the curvature has occurred is corrected to the following radius of curvature.

Elongation side: ρ-W/2 (ε1-Δεl) -...= (5)
Shrinkage side: ρ−W/2 (−ε2+Δεriichi・−・−(6)
Therefore, in order to eliminate the strain on the elongation side of the metal plate 1, the compressive strain Δε1 applied to the elongation side of the metal plate 1 by a roller leveler should be equal to ε1, and the strain on the contraction side of the metal plate l should be eliminated. To do this, the tensile strain Δε is applied to the contracted side of the metal plate 1 using a roller leveler.

The leveler roller pushing amount can be set so that the distance between the leveler rollers after pushing the leveler roller in the width direction becomes hh□ so that ε is equal to ε. In many cases, the leveler rollers are configured by rows, and in this case, the leveler roller pushing amount may be set so that the compressive strain Δε1 and the tensile strain Δε8 accumulate to a predetermined amount between the roller rows.

<Example> An example of the roller leveler used in carrying out the present invention is shown in FIG. 6. In FIG. 6, l is a metal plate, 2 is a leveling roll, 3 is a backup roll, and 4.4' is a width. Hydraulic lowering devices on the left and right sides in the direction, and 5.5' indicate electric lowering devices on the left and right sides in the width direction.

Radius of curvature ρ of camber caused by rolling. Based on this, the hydraulic pressure of the left and right hydraulic pressure lowering devices 5.5' in the width direction is changed respectively, and the leveler roller pushing amount is controlled so that the optimal width direction stress field for camber correction is formed on the metal plate 1. do.

Incidentally, even for a metal plate where the curvature of the camber is not constant, the camber can be corrected by controlling the hydraulic pressure lowering device 5.5' so that the amount of push of the leveler roller corresponds to the curvature. .

<Effects of the Invention> The present invention can effectively correct camber in the post-rolling process, reduce downgrades due to camber, and achieve a significant improvement in yield.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the strain distribution in the board width direction due to camber. FIG. 2 is a detailed explanatory diagram of the present invention, and the second
Figure (a) is a side view, Figure 2 (b) is 1- of Figure 2 (a).
It is a 1-line sectional view. FIG. 3 is an explanatory diagram of the stress distribution occurring in the board width direction in FIG. 2. FIG. 4 is an explanatory diagram showing the stress distribution in the thickness direction of a metal plate that is being straightened by a roller leveler. FIG. 5 is a detailed explanatory diagram of the present invention, showing the strain distribution in the plate thickness direction. FIG. 6 shows an embodiment of the apparatus used to carry out the method of the present invention. is a side view, Fig. 6 etc.)
is a front view. FIG. 7 is an explanatory diagram showing the influence of camber on the product. DESCRIPTION OF SYMBOLS 1... Metal plate, 2... Leveler roller, 3... Backup roll, 4.4'... Hydraulic lowering device, 5.5'... Electric lowering device, A... Product. Patent applicant: Kawasaki Steel Corporation Figure 1 <a><b> Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] When correcting the flatness of a metal plate using a roller leveler, by changing the amount of push of the leveler roller in the width direction,
A method for correcting the camber of a metal plate, comprising correcting the camber of the metal plate by giving a difference in the amount of elongation of the metal plate in the width direction.