JPS5973119A - Setting method of crown and flatness of rolled material - Google Patents

Abstract

PURPOSE:To set safely and exactly the crown and flatness of a rolled material by bending and pulling a rolled material which is passed through a roll array in a longitudinal direction, bending the same in a transverse direction and adjusting the transverse bending and the longitudinal plastic elongation. CONSTITUTION:A rolled material 2 is passed in an array consisting of plural rolls which are disposed zigzag, and a bending tension is applied on the material 2 in its longitudinal direction. The gap between the rolls 11 in the horizontal direction in a part of the roll group in the above-described roll array is widened to deflect the roll shaft or to crown the rolls 11, thereby applying bending on the material 2 in its transverse direction. The transverse bending and longitudinal plastic elongation are adjusted according to the thickness distribution of the material 2 on the inlet side. The crown and flatness of the rolled material are thus safely exactly set.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for correcting the crown and flatness of a rolled material. Generally speaking, the flatness of a rolled material refers to shapes such as mid-elongation, edge elongation, undulation, etc. Or, it refers to warping over the entire width direction, and the rolling margin claran refers to the cross-sectional profile of the material.

In recent years, demands on the accuracy of crown and flatness of rolled products such as steel plates have become stricter. In a conventional rolling mill,
Although the thickness of the rolled material in the longitudinal direction can be controlled with relative precision by an automatic thickness control device, the thickness of the material in the width direction is controlled by a roll bender, so there is a limit to thickness control.

Therefore, rolling mills equipped with axially movable rolls and rolling mills equipped with variable crown rolls were developed to replace roll benders and improve the accuracy of the crown and shape of materials. .

The former rolling mill controls the upturn of the work rolls by moving intermediate rolls of six stacked rolls in opposite directions in the axial direction. The latter rolling mill provides a pressure receiving chamber between the ground of the roll and the sleeve, supplies a pressure medium to the pressure receiving chamber, and controls the amount of crown of the roll by adjusting the pressure of the medium.

All of these conventional techniques improve the rolling mill to improve the roll deflection control ability and reduce the crown of the material (thickness of 0.
It is quantitatively small in the range of about 5 to 2%. ) is as small as possible, but there is a limit to this, and a perfectly rectangular cross section cannot be achieved. Furthermore, if the crown of the material is made smaller during rolling, the material tends to meander, making the work unstable. Furthermore, in rolling mills, the crown of the material can be reduced to some extent by reducing the deflection of the rolls, but it is impossible to eliminate edge drops. Additionally, remodeling the rolling mill requires a large capital investment.

As an inexpensive method, it is possible to control the cross section of the rolled material into a rectangular shape by rolling down the middle and high parts in the thickness direction of the rolled material using light compaction rolling, but the shape of the rolled material deteriorates extremely and operation becomes impossible. Become.

In view of the above facts, the present invention is a completely new attempt to correct the crown of material generated in a rolling mill by bending and tensile plastic deformation.

Shape defects in rolled materials are caused by differences in longitudinal elongation of the material, and cannot be corrected unless plastic elongation is imparted to the material.

Roller leveler has poor warpage (especially warpage in the longitudinal direction)
It is designed to correct the shape and reduce residual stress, so its ability to correct shape defects is low.

In order to give plastic elongation to the material with rollers and shimata, it is necessary to actively apply axial force. With conventional roller levelers, the residual stress in the material and the frictional force generated between the roll and the material only act as a slight axial force, and basically they cannot impart plastic elongation, and their ability to correct shape defects is low. .

Tensions and levelers have been developed to correct shape defects in rolled materials. This tension/leveler applies bending and tension to the interest to correct shape defects. The difference in elongation length of materials due to rolling mills is usually about 0.1%, and this causes shape defects such as medium elongation and ear waves. If this is stretched by about 0.2 to 15% using a tension leveler, the material will become flat. For this reason, the maximum elongation rate of conventional tension levelers is about 1 to 1.5%.

However, since it is usually used at the minimum necessary elongation rate, the reduction in thickness and width of the material caused by the tension leveler is extremely small and is ignored in practice. After all, in the conventional method, there was no idea of using tension and stiffness to straighten the crown of rolled material.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for correcting the crown and flatness of a rolled material inexpensively and accurately by making maximum use of existing techniques.

Before explaining the present invention in detail, we will explain the crown (OR) S and edge top (ED) of the rolled material used here.
With reference to FIG. 1, s-e is defined as follows.

(OR) s=ho-hs (ED) s-e=bs-he However, h. : Thickness at the center of the cross section of a rolled material with a width of 2G 11S: Distance S from the edge of the cross section of the rolled material to the center side
Thickness at a distance ho: Thickness at a distance e from the edge of the cross section of the rolled material toward the center The method of the present invention involves passing the rolled material through a plurality of rows of rolls arranged in a staggered manner; applying bending tension in the longitudinal direction of the material, applying bending in the width direction of the material by some roll groups of the roll rows, and applying bending in the width direction and longitudinal direction according to the entrance thickness distribution of the material It is made by adjusting the plastic elongation in the direction.

The specific method of bending the rolled material in the width direction is as follows:
There are the following six.

First, the first method is to widen the horizontal roll spacing of some of the roll groups in the roll row, and to bend the roll shafts or provide crowns to the rolls.

A second method is to widen the horizontal roll spacing of some of the roll groups in the roll row, form a crown on one side of at least one pair of rolls among the roll groups, and set the crowns opposite to each other. and the pair of rolls are moved in opposite directions in the axial direction. This method can respond to changes in the width of the material and is highly effective for any size.

A sixth method is a combination of the first method and the second method, in which the paired rolls are moved in the axial direction, and at least one roll other than the paired rolls is moved. The shaft is deflected or the roll is crowned.

Next, the method of the present invention will be specifically explained with reference to the drawings. Bending tension was applied to the rolled material 2 using a conventional tension leveler 1 shown in FIG. 2, giving the material 2 a plastic elongation of 5%. This 5% plastic elongation is 0 in normal shape correction.
．． Since it is about 2 to 0.5%, it can be said to be an extremely large increase that cannot be expected from the concept of shape correction. The test rolled material 2 is a cold rolled steel strip, and its dimensions are 1. O
film x width 200M. tension leveler 1
The diameter of the rolls 11 is 50 mm and the number of rolls is 8.

FIG. 6 shows the cross-sectional profile of the rolled material 2 when bending tension is applied to the rolled material 2 under the above dispute.

In Figure 6, the solid line? 7Z is the base material (as it is a slit material made from a wide material, the thickness is uniform in the width direction).
The solid line f shows the case where roll bending was not performed, and the dotted line shows the case where roll bending was performed.

As can be seen from Figure 6, when an extremely large plastic elongation, which has never been applied before, is applied to a rolled material using a tension leveler, the thickness of the edge portion in the width direction of the material becomes thicker (hereinafter referred to as edge up). ) occurs.

The cause of this edge-up is currently under investigation, but it can be estimated as follows.

When a strong bending tension is applied to a rolled material, the edges of the material are bent in the longitudinal direction as well as in the width direction, resulting in a large strain in the width direction of the material and a decrease in the thickness of the edge. It is understood that this is because it becomes smaller.

In other words, the following equation is generally established according to the law of constant volume due to plastic deformation of materials.

(1) Regarding the central part of the material in the width direction with only longitudinal bending and no width bending, εθ + εb + εh =.

However, εe: Strain in the longitudinal direction at the center of the material εb: Strain in the width direction at the center of the material εh: Strain in the thickness direction at the center of the material (2) Regarding the widthwise edge of the material where longitudinal and widthwise bending coexist, ε′e+ε′b+ε′h−O However, ε′o: Strain in the longitudinal direction of the edge of the material ε′b: Strain in the width direction of the edge of the material ε′h: Strain in the thickness direction of the edge of the material In this example, εe - ε e, but the edge portion of the material generates a bending force in the width direction, which increases strain in the width direction, resulting in εb<ε'b. the result,
εh〉ε′h (edge up) is established. Note that this bending of the edge portion in the width direction is a phenomenon that occurs because the material is bent in the longitudinal direction, and the edge-up phenomenon does not occur simply by pulling.

In addition, ε. It should be noted that the flatness correction of the material is also achieved at the same time since =ε/e.

Therefore, if you use Edge Up, you will be able to eliminate Edge Drop. However, this is limited to the edges of the material, so if this edge up is developed to the center of the width of the material, in other words, the width direction bending is not only applied to the edges of the material, but also to the center of the width of the material. It can be easily inferred that if the material is penetrated to this level, it will be possible to control the material crown.

As a method of permeating the widthwise bending of the material from the edge of the material to the center of the width of the material, as shown in FIGS. Widen the roll spacing and deflect the roll shaft. Fourth
The reason for widening the roll interval as shown in the figure is to make it easier to bend the material in the width direction. The roll shaft can be deflected by using a hydraulic cylinder (Fig. 5), by using a split backup roll 12 IC (Fig. 6), or by supplying fluid to the pressure chamber formed between A, P and sleeve. A variable crown roll (not shown) may be used to change the crown of the roll.

A normal crown + d roll may also be used.

When a bending tension is applied to the material with the roll 11 bent, the thickness distribution in the width direction of the material becomes as shown by the dotted line in FIG. The more severe the bending, the more concave and round-sized the thickness distribution becomes.

Instead of deflecting the roll shaft, as shown in FIGS. 7 and 8, the horizontal distance between the rolls 11 on the upstream side of the level 1 is widened, and a crown is formed on one side of at least one pair of rolls 110. , the crowns may be provided on opposite sides and the pair of rolls may be moved axially in opposite directions.

When such a round roll is used, the thickness distribution in the width direction of the material is as shown by the curve shown by the dotted line in FIG. 6, as described above.

The above has mainly explained the case where the rolled material is a cold-rolled steel strip, but since the higher the temperature of the material, the greater the plastic elongation of the material at lower tensions, this also applies to hot-rolled materials. The method of the invention is fully applicable. For example, the method of the present invention can be effectively applied to hot rolling lines, continuous annealing lines, galvanizing lines, etc.

As a method of imparting tension to the rolled material, as shown in FIG. 9, a ply roll roll (A) and a pinch roll 4 (B
), or a rolling mill 5(C) or a combination thereof.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the rolled material. Figure 2 is an explanatory diagram of normal tension/shihau. FIG. 6 is a graph showing the cross-sectional profile of a rolled material when large plastic elongation is applied. FIG. 4 is an explanatory diagram of tension leveling to which the method of the present invention is applied. FIG. 5 is a front view taken along line ■-V in FIG. 4. FIG. 6 shows a modification of FIG. 5. FIG. 7 shows a modification of FIG. 4. FIG. 8 is a plan view taken from the ■-Vl line in FIG. 7. FIG. 9 is an explanatory diagram showing a method of applying tension to rolled material. 1: Roller leveler 2: Rolling material 11 leveler
Roll Procedure Amendment Book dated April 2, 1981, Case Description Patent Application No. 185271 of 1982 2, Name of Invention Method for Correcting Crown and Flatness of Rolled Material 3, Person Making Amendment Case and Relationship Patent Applicant Address Name (211) Sumitomo Metal Industries Co., Ltd. 4, Agent 6, Contents of Amendment (1) “It will be as follows” in line 16 of page 12-<- of the specification. is corrected as follows. The thickness distribution will vary greatly depending on whether the deflection shape or crown shape of the roll is convex, concave, or has a complex waveform. It was confirmed that not only convex crowns and concave crowns but also complex thickness distribution in the width direction can be achieved at the same time as flatness correction.'' (2) Specification No. 16R-G line 8 ``It is possible to...''. ” is corrected as follows. When the tension is low, the width is wide, the amount of deflection of the roll is large, and the amount of crown of the roll is large, the rolled material does not stick tightly to the roll over the entire width, and some parts of the material are lifted, causing the width to deteriorate. The bending in the direction may be small. In such a case, the effect of the present invention will be increased by achieving close contact using the method shown in FIG. 16
The method of applying pressure to the strip by applying pressure to the strip, and the method of applying pressure to the strip by using the roll 14 for changing the tension distribution installed before (after) the insulating roll 11.
The degree of adhesion can be increased by pressing down. Instead of applying pressure using the presser roll 16, it is also effective to apply pressure by spraying fluid. Even when the leveler roll and the rolled material are in perfect contact, it is possible to change the thickness distribution in the width direction by changing the tension distribution in the width direction using the tension distribution changing roll 14. Although the present invention describes a method in which bending and tensioning is performed using rolls arranged in a staggered manner, the same applies to bending and tensioning using a fixed tool other than rolls, and the present invention also includes a fixed tool method. included. ” (3) Specification letter 16 is written in lines 18 to 20 of “...”
An explanatory diagram showing...・・・・・・・・・・・・・11 Nilevera Roll” will be corrected as follows. Explanation and clear diagram showing ``...''. Figure 10 is an explanatory diagram showing a method for reducing poor adhesion between the roll and the rolled material. 1: Tension/Shihara 2: Rolled material 16: Presser roll 14: Roll for changing tension distribution (4) Attached Figure 10 is added.

Claims (4)

[Claims] (1) Passing the rolled material through a plurality of rows of rolls arranged in a staggered manner, and applying bending tension in the longitudinal direction of the material;
A rolled material comprising applying bending to the material in the width direction by some roll groups of the roll rows, and adjusting width direction bending and longitudinal direction plastic elongation according to the entrance thickness distribution of the material. Crown and flatness correction methods. (2) widening the horizontal roll spacing of some of the roll groups in the roll row and flexing the roll shaft;
The method according to claim 1, characterized in that the rolled material is bent in the width direction by providing a roll with a crown. (3) The horizontal roll spacing of some of the roll groups in the roll row is increased;
A crown is formed on one side of the pair of rolls, the crowns are provided on opposite sides, and the rolled material is bent in the width direction by moving the pair of rolls in opposite directions in the axial direction. Claim No. 1 (1)
) Method described in section. (4) The roll spacing in the horizontal direction of some of the roll groups in the roll row is increased, and
<A crown is formed on one side of a pair of rolls, the crowns are provided opposite to each other, and the pair of rolls are moved relative to each other in the axial direction, and five of the roll groups, excluding the rolls forming the pair, Claim (1) characterized in that the rolled material is bent in the width direction by deflecting at least one roll shaft or by applying a crown to the rolled material. The method described in section.