JPS62203603A - Method and apparatus for cross rolling down of steel strip - Google Patents

Abstract

PURPOSE:To improve the productivity of a product and to improve the surface quality thereof by rolling down the side faces of a steel strip with a pair of vertical edger rolls and bending the steel strip near the rolling down position. CONSTITUTION:The steel strip S descaled after hot rolling is bent by using a deflector roll D1 and a bending roll B1 and is then rolled down in the transverse direction by pinch rolls P and vertical rolls V. Since the buckling load to the rolling down in the transverse direction is increased, only the edge parts are effectively edged. The productivity of the product is improved and the edge drop of the steel strip is effectively prevented by the above-mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for width reduction of a steel strip.

(Prior art) In the process of cold rolling a steel strip, the roll flatness during rolling changes rapidly near both ends of the steel strip in the width direction, causing movement of the material in the width direction, causing the steel strip to Edge drops (
(thin wall part) occurs. For this reason, if it is not possible to roll a product with sufficient dimensional accuracy for the width and thickness tolerances of the product, a rotating round blade shear (side trimmer) is used during the finishing process.
The defective parts are removed and the product is collected.

However, in this side trimming, both edges of the steel strip are cut off over several nanometers to several tens of nanometers, which is undesirable because it leads to yield loss.

As a means to compensate for this point, Japanese Patent Application Laid-Open No. 58-184006 proposes a method and apparatus for controlling the width and thickness of a steel strip.

Figure 5 shows a basic unit of rolls constituting the invention, in which the left and right sides form a pair of vertical rolls V that press against both edges of the steel strip S, and the plate width is the same as the position where the vertical rolls V are pressed against the steel strip. A horizontal roll H that is located on the direction line and presses against the upper and lower surfaces of both edge approaches of the steel strip S, a buckling prevention roll B that is arranged between the left and right horizontal rolls, and a group of these rolls. It consists of a pair of upper and lower pine shear rolls M located slightly downstream of the pine shear roll M for correcting and rolling down the edge thickened by the width reduction K. Combining multiple sets of such devices has the effect of improving the thickness and width accuracy of the material, but with this method and device there is a limit to the width of the material plate that can be processed unless the pack ring prevention roll B = i is replaced. There was a flaw that I believed.

(Problems to be Solved by the Invention) An object of the present invention is to efficiently improve the edge drop of a steel strip, and to improve the efficiency of rolling mill 1v! The object of the present invention is to provide all practical means to achieve this without reducing the production efficiency, and to further improve quality and yield9.

(Means for Solving the Problems) The present invention provides a solution to bank ringing at the center of the steel strip due to width reduction when cold rolling a descaled steel strip after hot rolling. In order to prevent this, a vertical roll is used to roll the steel strip, and a bending roll is installed near the rolling position to apply a bend.
It is designed to roll down the width of the steel strip.

This was done based on the knowledge that when tension is applied in the longitudinal direction of the steel strip, the load that causes the central portion of the steel strip to buckle increases significantly near the bending rolls that are being bent. This buckling load varies depending on the thickness of the steel strip, the longitudinal tension of the steel strip, the distance between the bending rolls and the width reduction point, and the arrangement of the bending rolls with respect to the width reduction point, but by appropriately selecting the conditions, It is possible to obtain a buckling load greater than the width reduction load required to increase the plate thickness near the edge by width reduction.

(effect) Next, the present invention will be explained in detail using FIG.

The left and right sides form a pair of vertical rolls V that press against both edges of the steel strip S, and the vertical rolls V are located on the same sheet width direction line as the position where the vertical rolls V press and engage with the steel strip, and are closer to both edges of the steel strip. Pinch rolls P press and engage with the upper and lower surfaces of the steel strip S, and vertical rolls V are located upstream and downstream close to the position where they press and engage the steel strip S, and are in contact with the steel strip surface and bend the steel strip S. Bending rolls Bl and B2 and deflectors for changing direction
It consists of rolls DI and L)2.

The reason why bending the steel strip S in this way is advantageous in preventing buckling at the sides is as follows.

Conventionally, installing a presser roll on the rolling axis of the vertical roll V in Fig. 5 is equivalent to compressing a short column,
Frustrated 9! The theory is based on the known knowledge that shorter boards are less prone to buckling. On the other hand, there is a bending roll Bl near the vertical roll V in FIG.

In the B2i installation method, the restraint location is off the rolling axis, so it is thought that the buckling prevention effect will be reduced, but the inventors have found that this buckling preventing effect is reduced by the actual plate width shown in Figure 5. This occurs because the buckling mode of a narrow flat plate shifts to buckling mode of buckling a half-cylindrical plate due to bending.

In other words, the present invention uses the principle that compressing a cylinder is less likely to buckle than compressing a flat plate.

Therefore, simply placing the pinch upper and lower rolls pt in the positions of the bending rolls Bl and B2 in FIG. 2 of the present invention and simply sandwiching the plate without bending the plate will not produce the remarkable buckling prevention effect as in the uninvention, and This leads to a mere extension of the invention.

In addition, the present invention has the characteristic that the effect of buckling the bent object does not deteriorate even when the width is wide.

(Example) FIG. 2 shows the front view of FIG. 1.

That is, by providing the bending rolls Bl and B2'i, the bending is applied, so that the seat /l1flf attached to the widthwise reduction
Even if the weight increases and the entire edge width is reduced, the steel strip will not buckle and only the edge portion will be reduced in width.

Therefore, width reduction can be advantageously performed in the vicinity where the steel strip is bent in this manner.

FIG. 3 shows another embodiment, and the difference from FIG. 1 is that the vertical roll l is at the same position on the strip width direction line as the position where the steel strip S is pressed into contact with the steel strip S, and at the center in the strip width direction. A narrow pinch roll P is additionally arranged.

When the maximum plate width of the processed material is wide, or when bending rolls Bl, B
2 and the reassembled roll 1 cannot be made small enough,
Suitable for low tension.

Figure 4 shows an example installed between the stands of a tandem cold rolling mill, where V is a vertical roll that presses into the edge of the steel strip, P is a pinch roll, B1 is a bending roll, and Dl is a deflector roll. be.

Curved rolls are placed only on the upstream side of the vertical rolls, but are suitable when the tension in the steel strip is high, such as between the stands of a tandem rolling mill.

(Effects of the invention) According to the invention, 1- It is a simple mechanism, and there is no core wall for changing rolls when the plate width of the processed material changes, and edge drop of the steel strip due to width reduction can be effectively prevented. It is possible to do so.

[Brief explanation of drawings]

FIG. 1 is a plan view of the entire structure of the width reduction method and apparatus according to the present invention, FIG. 2 is a front view of FIG. 1, and FIGS. Figures 1 and 5 are explanatory diagrams showing a conventional width rolling method and device. Bl and B2 are bending rolls, DI and B2 are deflector rolls, P is a pinch roll, ■ is a vertical roll, and S is a steel strip.

Claims (2)

[Claims] (1) When cold rolling a descaled steel strip after hot rolling, a pair of vertical edger rolls rolls down the sides of the steel strip, and bends the steel strip near the rolling position. A method for width reduction of a steel strip characterized by the following. (2) When cold rolling a descaled steel strip after hot rolling, a pair of vertical edger rolls and a steel strip upper and lower surface pressing roll are combined at the same position in a device that rolls down the side surface of the steel strip. A steel strip width rolling device characterized in that a steel strip bending roll is arranged close to a rolling position by a vertical roll.