JPH0327284B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for uniformly controlling the width and thickness of a descaled steel strip.

During the rolling process of steel strip, it is inevitable that edge drops (thin walled parts) occur at both ends in the strip width direction. Side trimming is performed using blade shearing. However, in this side trimming, both edges of the steel strip are cut off over several millimeters to several tens of millimeters, so there is a drawback that it usually causes a yield loss of 1 to 2%. Depending on the properties, the edges of the product after cold rolling may become sawtooth-like, resulting in a deterioration in quality.

As a means to compensate for this drawback, the present inventors have descaled steel strip at the same time in the strip width direction and the strip thickness direction, for example, at the outlet side of a pickling line or at the inlet side of a cold rolling tandem mill. A method has already been developed for correcting the reduction in thickness and thereby obtaining the desired thickness without side trimming by shearing (Japanese Patent Application No. 47689/1983).

In this earlier application, the basic technical idea is that, as shown in Fig. 1A, a steel strip a of uneven width with edge drops b at both ends is first rolled by vertical rolls V as shown in Fig. 1B. Correct the width. At this time, a slight bulge d is generated at the edge of the steel strip a due to the reduction, resulting in a so-called dogbone shape, but at the same time the upper and lower horizontal rolls H This presses down the steel strip to prevent branch breakage and swinging, and at the same time, the bulge d of the edge portion is pressed toward the center and is made uniform across the entire width.

Therefore, in order to prevent the plate width W corrected at the time of width adjustment in Fig. 1B from being distorted at the time of vertical reduction shown in Fig. 1C, the correction reduction of the plate width and the correction reduction of the plate thickness are carried out. and in the same position, or
Or do it almost simultaneously at slightly different positions. When the amount of correction of the sheet width or thickness is large, the above-mentioned reduction correction process is performed at multiple consecutive positions to appropriately share the amount of correction, and the roll spacing of the final set is adjusted to the desired sheet thickness T and sheet width. Set each to W.

Rolling using such a control means is extremely effective as it can improve the width accuracy without causing trimming loss, but looking at the width of the material rolled using the method of this prior application, it is found that As shown in Figure 2, although the target value R is controlled over almost the entire length of the material in the longitudinal direction, there is a large error in a certain range between the top T and bottom B of the material, and it is not necessary to satisfy the target value R. This is not consistent with the control results.

Therefore, an object of the present invention is to provide a means for stably controlling the width and thickness of a material over the entire length of the material, including the top and bottom, by further improving the control means of the prior application. The aim is to further improve quality and yield.

In the present invention, the same roll configuration as in the previous application is used as a basic unit, and multiple sets are provided on the line.
The upstream side is selectively used as the width rough pressure lower part, and the downstream side is always used as the width tight pressure lower part.

As shown in Fig. 3, the basic units of rolls constituting the present invention are a pair of vertical rolls V that press against both edges of the steel strip a, and a position where the vertical rolls press and engage with the steel strip. A horizontal roll H that is located on the same line in the sheet width direction and press-fits into the upper and lower surfaces near both edges of the steel strip, a buckling prevention roll B that is placed between the left and right horizontal rolls, and these rolls. It consists of a pair of upper and lower masher rolls M that are located slightly downstream of the group and correct the edges that have been thickened by width reduction.

Next, a specific example of an apparatus for carrying out the method of the present invention is shown in FIG. Since this device is installed symmetrically opposite the positions of both edges of the running steel strip, only one side thereof will be described.

The roll housing 1 is integrally fixed to the sliding bed 11 and is movable in the width direction of the board, and also incorporates two horizontal rolls H and one vertical roll V, which form a pair of upper and lower sides. be. The three rolls are assembled on the same line in the width direction of the sheet at a position where they can be press-fitted and engaged with the steel strip a simultaneously from three directions (up, down, and lateral).

The upper horizontal roll H is movable in the vertical direction by a fluid pressure cylinder 21, supported so as to be able to adjust the amount of rolling down, and the rotation of the drive motor 22 is transmitted through a universal joint. Lower horizontal roll H
is an idle roll, and a bearing is fixed to the roll housing 1. Similarly, the vertical roll V is also made into an idle roll. The roll housing 1 incorporating these rolls is pressed toward the edge of the steel strip a by a hydraulic cylinder 5, causing the vertical rolls V to perform a desired rolling reduction.

A buckling prevention roll B is horizontally arranged between the left and right pair of roll housings 1 facing in the strip width direction, and presses the top and bottom surfaces of the steel strip as an idle roll.

A roll unit A and a masher roll M having the configuration shown in FIG. 4 are arranged one after another on a rolling line as shown in FIG. shall be. A plurality of units A and one masher roll M are arranged as a set on the downstream side, and this is used as the width tight compression lower part 20.

In the method of the present invention, after a target strip width value is set for the final set of roll units in the width compaction lower part 20, strip width and strip thickness are simultaneously rolled. The width roughening section 20 is constantly operated to perform rolling over the entire length of the steel strip a, but the width roughening section 10 is not used for rolling the normal section, and the top T and bottom B of the steel strip a are rolled. It is selectively used only when passing the sheet through, and the width roughening lower part 10 and the width tight rolling lower part 20 are used redundantly for rolling.

An example of the use of the device 100 of the present invention configured in this way is shown in FIGS. 6 and 7. The example in Figure 6 is
This device is installed next to the pickling tank 50 and winds up after correction reduction. The example shown in FIG. 7 is provided on the entry side of the cold rolling mill 60 to perform corrective rolling and then cold rolling. In either case, the edge drop of the steel strip is removed, the plate crown is also reduced, and the plate width accuracy is satisfied.

Next, specific examples according to the method of the present invention will be described. Plate width variation target value ±3mm, plate crown 60μ
Descaled pickled hot rolled steel strip (3.0mm x 1236mm x
25 tons) was passed through the installation line of this equipment, and by applying pressure in the board thickness direction and board width direction, we were able to make the board width uniform to 1232 mm. In this case, 14mm of the trimming allowance was conventionally cut off, so this amount was made into a finished product, resulting in an improvement in trim yield of 1.1%. Furthermore, the edge drop after cold rolling was reduced by 9μ compared to the method of the prior application. This eliminates the need for unnecessary thickening of 9μ compared to conventional products.
Yield improved by 0.9%.

As described above, according to the control method of the present invention, the reduction can be corrected simultaneously in the width direction and the thickness direction of the steel strip, and moreover, the reduction can be corrected to a uniform value over the entire length including the top and bottom parts. Width accuracy can be further improved without causing trimming loss. Therefore, it is extremely effective in improving the product yield.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing step by step the principle of the rolling correction process of the present invention. FIG. 2 is a diagram showing the board width control state before implementing the method of the present invention. FIG. 3 is a top view showing the configuration of the basic unit according to the present invention. FIG. 4 is a front view showing one embodiment of the device according to the present invention with one symmetrical side omitted. FIG. 5 is a perspective view of an embodiment of the device of the present invention.
FIGS. 6 and 7 are schematic explanatory diagrams showing an example of use of the apparatus of the present invention. I: roll, housing, H: horizontal roll,
V: Vertical roll, M: Masher roll, B: Buckling prevention roll, a: Steel strip, 10: Width rough pressure lower part, 20: Width density control part.

Claims (1)

[Scope of Claims] 1. In a line on which a hot-rolled and descaled steel strip runs, at least one pair of vertical rolls for width reduction provided in pairs on both sides of the running line; A basic unit having an edge rolling horizontal roll that presses and engages the upper and lower surfaces of the steel strip near both edges, and a pair of buckling prevention rolls that press and engage the upper and lower surfaces of the steel strip between the left and right horizontal rolls; Using a width roughening equipment consisting of a pair of masher rolls located downstream of the pressure-welding engagement position of the rolls and which corrects and rolls down edges that have increased in thickness due to width reduction, only the longitudinal ends of the steel strip are In contrast, a coarse control process for reducing the width and thickness of the steel strip, and a width-tight reduction equipment consisting of a plurality of sets of the basic units and a pair of masher rolls are used to reduce the overall length of the steel strip. A method for controlling the width and thickness of a steel strip, characterized in that a density control step of correcting the width and thickness of the strip is performed at least once each, so that the desired strip width and thickness can be obtained in the final reduction. . 2. At least one pair of vertical rolls for width reduction provided in left and right pairs on both sides of the steel strip running line;
An edge rolling horizontal roll that presses and engages the upper and lower surfaces near both edges of the steel strip at the same position on the sheet width direction line where the vertical roll presses and engages the steel strip, and a steel strip between the left and right horizontal rolls. a basic unit having a pair of buckling prevention rolls that press and engage with the upper and lower surfaces of the horizontal roll, and a pair of masher rolls that are located downstream of the press and engage position of the horizontal roll and correct the edge thickness increased by width reduction. A width and thickness control device for a steel strip, comprising a coarse width reduction facility comprising a plurality of sets of the aforementioned basic units and a pair of said masher rolls.