JPS61226107A - Method for discriminating shape of rolled steel plate - Google Patents

Abstract

PURPOSE:To prevent a rolling trouble by correcting a tension distribution signal by a gap signal to discriminate the potential shape of a steel plate and discriminating the sensible shape of the steel plate when the gap signal increases to a permissible value or above. CONSTITUTION:A magnetic permeability sensor 1 is installed to the bottom surface of the steel plate P and is traversed in the transverse direction of the steel plate. The shape of the steel plate is discriminated from the tension distribution signal S1 and the gap signal S2. The tension distribution signal S1 and the gap signal S2 are sampled. The signal S2 is nearly a square wave as shown by a solid line when the shape of the steel plate is potential. The signal is the wave shown by a broken line when, for example, the middle waviness is sensibly formed. The tension distribution signal S1 is corrected by the gap signal S2 and the potential shape is discriminated if the shape is potential. The sensible shape of the steel plate is discriminated when the gap signal S2 increases to the permissible value or above. The shape adjustment of rolls, etc. are executed from the results of such discrimination so that the results of the discrimination are reflected in the actual control.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for determining the shape of a rolled steel plate during cold rolling or the like.

<Prior Art and its Problems> In recent years, in rolled products such as steel plates, requirements have become stricter not only for plate thickness and plate width but also for plate shape. Among these shapes, various devices and methods have been devised to measure flatness such as mid-elongation and edge elongation.

In particular, a magnetic permeability sensor is used across the width of the steel plate as an effective means for measuring the shape of a steel plate, which is manufactured under high tension such as cold rolling, so that defective shapes usually become latent. There is a method that measures the tension distribution.

The output signal of this magnetic permeability type sensor includes one that detects the tension distribution in the width direction of the steel plate as a change in magnetic permeability (referred to as a tension distribution signal in this specification), and one that detects the distance change between the sensor and the steel plate when crossing the sensor. (herein referred to as a gap signal), which is effective for measuring latent shapes.

Of these two signals, the important one in determining the shape is the tension signal, and the 5-gear signal is normally used only to correct tension signal changes caused by gap fluctuations due to vibration of the steel plate. The shape of the is being determined.

However, if the gap variation becomes too large, this correction becomes difficult, so the range of gap variation that is effective for correction is minute, about ±11 or less. When applying this method, it is necessary to It is necessary to provide a mechanism to suppress vibrations.

However, in steady state, the unit tension is 3
Even if a high tension of ~5 Kf/wx2 is applied, the shape may not be completely hidden if the shape deteriorates considerably or the tension is temporarily reduced.

In such a case, the gear tooth variation force in the width direction of the steel plate mostly exceeds the above-mentioned allowable range, and the shape determined from the corrected tension signal does not match the actual shape.

This invention was proposed in view of these circumstances.
The purpose is to provide a method for determining the shape of a rolled steel plate that can determine whether or not the shape has become apparent and the shape that has become apparent by using the gap signal used only for correction.

<Means for Solving the Problems> The shape determination method according to the present invention corrects the tension distribution signal using the gap signal to determine the latent steel sheet shape, and when the gap signal exceeds a tolerance value, the shape is determined to be actualized. The revealed shape of the steel plate is determined and necessary processing is performed.

<Example> The present invention will be described below based on an illustrated embodiment.

As shown in Fig. 1, a magnetic permeability sensor 1 is attached to the bottom surface of the steel plate P.
is installed and made to cross in the width direction of the steel plate, and the shape is determined from the tension distribution signal S1 and gap signal S2.

The tension distribution signal S1 and the gap signal S2 are sampled, and when the steel plate shape is latent, the gap signal S2 becomes a rectangular wave as shown in the solid line as shown in Fig. When an elongated shape becomes apparent, it will be indicated by a broken line, so if the shape is made latent by the gap signal processing flow described later, the tension distribution signal S1 is corrected using the gap signal S2 to make the latent shape. When the gap signal S2 becomes equal to or greater than the allowable value, it is determined that the shape of the steel sheet has become apparent.

Based on these judgment results, we adjust the roll shape, etc.
Reflect in actual control.

FIG. 3 shows an example of a gap signal processing flow, in which a gap signal EG having a sampling number NW is processed as follows.

(a) Divide the entire board width into five parts: WS, WSS four center, Ds quarter, and DS. This division method can be divided into 5 equal parts, but quarter extension (2nd and 4th extension)
Empirically, N1 = Q, 2 NW, N2: 0.35 NWNs, as 2 is less important than middle extension 3 and ear extension 4 in terms of frequency of occurrence.
== 0.65 NW, N4= 0, 8 NW
to a certain degree.

In each range divided in this way, shape manifestation is determined by the following loop.

(b) For the sampling value KG, take the deviation from a certain value and compare it with the allowable value ΔL.

Here, L: Average level ΔL of the gap signal when the shape is revealed:
Both gap signal changes corresponding to the variation in the range in which gap correction is effective are constants and can be easily determined experimentally.

If we simply look at the gap signal, in the case of the broken line in Figure 2, there are two possibilities: overt mid-stretch and overt ear-stretch on both sides. can be determined.

(c) Count the number of samples in which the deviation at b exceeds the allowable value ΔL; (d) If this exceeds a certain value, determine whether it has manifested.

This is to prevent noise and erroneous detection of ritsu, dibuckle, etc. The value of k is determined by the sensor movement distance in the sampling period.

Here, it is not necessary to perform counting separately depending on the sign of the deviation from L. This means that, for example, when mid-elongation has become apparent, the pattern of the gap signal S2 will change to
This is because several cases are possible as shown in the figure.

Next, FIG. 7 shows an example of a chart when a shape is revealed. These are the gap signal S2 and the corrected tension distribution signal S11 when the edge elongation (unilateral elongation) gradually worsens and becomes obvious.

In the corrected tension distribution signal s, r, in case (Iiii), due to the large gap fluctuation due to manifestation, (1), (
Since the sharp peak indicating selvage elongation, such as the 0 portion of j), has disappeared, correct determination cannot be made, but it is possible to determine selvage elongation from the gap signal S2 by the above-described processing.

<Effects of the Invention> As described above, according to the present invention, it is possible to determine whether or not a shape has become apparent and the shape that has become manifest by using the gap signal that was used only for correction, and this determination result can be used in actual control. By reflecting this, for example, by accurately detecting deterioration in edge elongation in particular, rolling troubles in the mill such as drawing can be prevented. Furthermore, it is possible to improve controllability in the top and bottom portions of coils that are generally in poor shape, and to reduce devaluation and downgrading due to poor flatness.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the shape determination method according to the present invention, Fig. 2 is a schematic diagram showing the shape of the steel plate and the shape of the gap signal, Fig. 3 is a flowchart showing an example of the gap signal processing flow, and Fig. 4 is a schematic diagram showing the relationship between shape defects and sampling, Fig. 5 is a graph showing an example of change in gap signal, Fig. 6 is a graph showing change in gap signal due to change in line speed, Fig. 7 is gap signal This is a graph showing the corrected tension distribution signal.
Tension distribution signal, 82 (KG)... Gear knob signal Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) A method of determining the shape of a rolled steel plate by moving a magnetic permeability sensor across the width of the steel plate based on its tension distribution signal and gap signal, in which the tension distribution signal is corrected and made latent using the gap signal. 1. A method for determining the shape of a rolled steel plate, characterized in that the shape of the steel plate is determined, and when a gap signal exceeds a tolerance value, the shape of the steel plate is determined to have become apparent.