JP2818096B2 - Manufacturing method of steel plate with projections with excellent thickness accuracy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a steel sheet with projections having excellent thickness accuracy. More specifically, for example, the present invention relates to a method for rolling a steel sheet with projections supplied for the purpose of improving the bonding between a spiral steel pipe using the steel sheet and concrete or the like and reinforcing the same.

[0002]

2. Description of the Related Art Conventionally, in the production of a steel sheet with projections, a caliper is filled with a rolled material to obtain projections having a desired height. However, in order to obtain projections suitable for various purposes, there is a drawback that a caliber roll suitable for each purpose must be prepared.

[0003] In order to solve this drawback, a method of rolling by using a caliber roll having a caliper depth larger than the maximum value of the protrusion height obtained by rolling is disclosed in Japanese Patent Laid-Open No. No. 54502 is disclosed.

[0004]

The steel plate with projections obtained by these disclosed methods can certainly obtain the required projection height, but the accuracy of the portion without projections, that is, the so-called base plate thick portion, can be obtained. Not sure. That is,
There is no description of a method for properly maintaining a certain amount of reduction, and it is not possible to obtain a highly accurate sheet thickness over the entire length of the steel sheet only by this method. Therefore, in order to guarantee the required thickness over the entire length of the steel sheet, it is necessary to perform an operation of setting the actually rolled thickness to be larger than the required thickness. As a result,
It has the drawback of inferior yield.

[0005]

Means for Solving the Problems The present invention has been made to solve the above problems, and the gist of the present invention is as follows.
It is as follows.

(1) In rolling and manufacturing a steel sheet with projections using caliber rolls arranged in the sheet width direction, a signal obtained using a sheet thickness measuring device that can be swept in the sheet width direction and disposed after the final rolling stand. A method of manufacturing a steel sheet with projections, characterized in that the thickness of the steel sheet is controlled by the method.

(2) A projection characterized in that the thickness is controlled by using a signal obtained by limiting the traverse range of the thickness measuring device capable of sweeping in the width direction to a range narrower than the rolled steel plate. This is a method for manufacturing a coated steel sheet.

[0008]

Hereinafter, the contents of the present invention will be described in detail.

In general, plate thickness control is performed in a state where a measurement field of view is fixed at a center portion in a plate width direction, and automatic plate thickness control for feeding back to a reduction control, that is, so-called AGC (automatic thickness control).
A method of obtaining a good plate thickness by omatic gage control) has been adopted. However, when trying to measure the center sheet thickness in the sheet width direction with a steel sheet with protrusions, as is apparent from the cross-sectional shape in the sheet width direction of the steel sheet with protrusions shown in FIG. There are cases where the measurement field of view measures only the protrusion 1 of the steel plate with protrusions, the case where only the protrusion 2 is not measured, or the case where both are measured in the field of view. It can be seen that the plate thickness over a wide range from the protruding portion to the no-protrusion portion as shown in FIG. This phenomenon is due to a phenomenon in which the sheet shifts in the sheet width direction during the rolling, that is, a so-called meandering of the steel sheet relatively displaces the rolled material from the center of the rolling mill.

Therefore, when it is attempted to perform normal AGC control using the thickness signal measured by the conventional method, it is obvious that a hunting phenomenon occurs, and it is impossible to control the thickness.

Therefore, the inventors have conceived of controlling the thickness by using a thickness measuring device in the width direction which is usually used to measure a change in the thickness in the width direction, that is, a so-called plate profile.

FIG. 1 shows an example of a device arrangement for performing the above method. In the figure, reference numeral 3 denotes a steel sheet with projections to be rolled. 4,5,6
Is No. No. 1 stand, No. (Final-1) A stand and a final stand, in which a group of rolling mills is shown. In the case of this drawing, a caliber roll for rolling a steel plate with projections is arranged in the final rolling stand 6. On the downstream side of the final stand 6, a plate thickness measuring device 7 that can be swept in the plate width direction is arranged, and the signal is connected to a data processing device 8.

Next, FIG. 2 shows the thickness measurement results obtained by measuring the thickness of the steel plate with protrusions without any consideration by using the above-mentioned thickness measuring device capable of sweeping in the width direction of the steel plate. As is clear from the measurement results, the plate thicknesses of the protruding portions to the non-protruding portions are rather frequently recorded in the same manner as in the center plate thickness measurement used for normal plate thickness control. In the figure, reference numeral 10 denotes the thickness of the projection-less portion, and reference numeral 11 denotes the thickness of the projection portion.

However, the present inventors have devised a method of utilizing the frequent alternating characteristics. When measuring using a thickness measuring device in the width direction of the plate, since the protruding part to the non-protruding part are continuously measured positively, only the minimum value is subjected to data processing to make it continuous. It was noticed that the thickness of

That is, by removing the measured values above a certain threshold value and performing appropriate numerical processing, it is possible to obtain a continuous thickness of the portion without protrusions, and as a result, the normal thickness control can be applied without hunting. can do. FIG. 3 schematically shows the basic concept.

However, since a sheet thickness measuring apparatus capable of sweeping in the sheet width direction is mainly intended to measure the sheet thickness at the sheet edge, when the sheet is traversed in the sheet width direction, the sheet passes through the sheet edge and the sheetless portion is not measured. In most cases, the measurement range is up to the measurement range. As shown in FIG. 2, each time the measuring device traverses in the width direction of the plate, a portion with the plate (region A) and a portion without the plate (region B) are measured. Will do. However, when the above-mentioned AGC control is applied, when the measurement device traverses beyond the plate edge, the measured value decreases rapidly, resulting in control disturbance. Therefore, the inventors propose to solve the problem by limiting the traverse range to the width of the plate. That is, by limiting the measurement range in the plate width direction to only within the plate width range, it is possible to obtain a steel plate with projections having even better thickness accuracy.

The simplest method of limiting the measurement range is to let the width direction traverse drive control unit of the sheet thickness device control the traverse range according to the following equation (1). For example, an example is shown in which the coordinates in the plate width direction with the line center as the origin are taken.

[0018]

-W / 2 + α ≦ X ≦ W / 2−α, where X: traversable range of the measuring device W: rolling width of the steel plate with projections α: distance from the edge that limits the measuring range

[0019]

Embodiments of the present invention will be described below in detail.

The sizes of the steel sheet with projections on which the inventors have carried out the invention described above are as follows. The final rolling stand in this case was a fourth finishing mill. (1) Board thickness: 14.0 mm (2) Board width: 1850 mm

FIG. 4A shows the thickness distribution before the application of the present method.
FIG. 4B shows the thickness distribution after application. Clearly, the accuracy of the thickness has been improved, indicating that the effect of the thickness control has been exhibited.

[0022]

According to the present invention, as described in detail above,
Since there was no method for properly measuring the rolled thickness of the non-projected portion of the steel plate with projections, satisfactory thickness accuracy was not obtained and the yield was degraded. By using an unprecedented new method of controlling the sheet thickness by using the method described above, it is possible to obtain a good sheet thickness accuracy and widely apply the method to a method of rolling a steel sheet with projections, which is expected to improve the yield.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a device arrangement for realizing the present invention.

FIG. 2 is a graph showing an example in which the thickness of a steel plate with projections is measured by a width direction thickness measuring device.

FIG. 3 is a diagram schematically showing a basic concept for recognizing the thickness of a portion without a protrusion.

FIG. 4A is a graph showing an example of a thickness distribution before applying the present method, and FIG. 4B is a graph showing an example of a thickness distribution after the application.

FIG. 5 is a perspective view showing a cross-sectional shape of a steel sheet with projections.

FIG. 6 is a graph showing the results of measuring the center thickness of a general steel plate with a center fixed thickness gauge.

FIG. 7 is a graph showing the results of measuring a steel plate with projections with a center fixed thickness gauge.

[Explanation of symbols]

 1 Projection of steel plate with projection 2 Non-projection part of steel plate with projection 3 Steel plate with projection 4 No. 1 stand 5 (final-1) stand 6 final stand 7 plate thickness measuring device capable of sweeping in the plate width direction 8 data processing device 9 data flow 10 plate thickness without protrusion 11 plate thickness with protrusion A portion with plate B plate Part without

Claims (2)

(57) [Claims] When rolling a steel sheet with projections using caliber rolls arranged in the sheet width direction, a signal obtained by using a sheet thickness measuring device that can be swept in the sheet width direction and disposed after the final rolling stand is used. A method for manufacturing a steel sheet with projections, characterized by controlling the thickness. 2. The method according to claim 1, wherein the traverse range of the thickness measuring device capable of sweeping in the width direction is limited to a range narrower than the rolled steel plate, and the thickness is controlled using a signal obtained. Steel plate manufacturing method.