JPH04279209A - Method for detecting waving of strip - Google Patents

Abstract

PURPOSE:To directly and quickly detect waving of strip on the pass line with high accuracy without estimation. CONSTITUTION:When a steel strip (strip) 12 is transported on a line, a water column type ultrasonic range finder 22 is provided oppositely to the above- mentioned steel strip 12 and leaving a distance H0 that the range finder is not brought into contact with the waving of steel strip. The distance to the steel strip 12 is measured with that range finder 22 and the waving amount HW of the steel strip 12 is detected from the measured distance.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a method for detecting waving of a strip, and particularly to a method for detecting waving at the tip of a strip of steel strip, film, paper, etc. when the strip runs on a pass line. The present invention relates to a strip waving detection method suitable for use in the present invention.

0002

[Prior Art] In recent years, there has been a strong demand for thinner hot-rolled products, and it is important to ensure that the rolling temperature is appropriate to ensure quality.
Furthermore, it is desired to increase the rolling speed in order to improve productivity. However, as the rolling speed of thin steel strips is thinner and the rolling temperature is higher, a waving phenomenon occurs at the tip of the steel strip from the time it leaves the finishing mill until it reaches the coiler (winding device). Easy to occur. As a result, the winding ability of the coiler decreases, leading to insufficient winding and poor winding (
The risk of occurrence of miscoils increases.

[0003] Therefore, it is necessary to detect this waving and take appropriate waving prevention measures.

On the other hand, a method for detecting and absorbing waving occurring in a steel strip is disclosed in Japanese Patent Publication No. 2-420.
This is shown in Publication No. 0.

That is, as shown in FIG. 5, a hot finishing mill 1
When the steel strip 12 is rolled at 0 and conveyed in the direction of the arrow in the figure, the length of the tip of the steel strip 12 passing through the finishing mill 10, that is, the tracking length LH, is estimated. This tracking length LH can be estimated using, for example, the mill rotation speed, roll diameter,
Calculate from the advanced rate using the following formula (1).

LH=Σ{mill rotation speed)×(roll diameter)×π(
1 + advanced rate)}…(1)

[0007] Also, finishing mill 10
There is a steel strip 12 at a distance L downstream from the mill 10.
A sensor 14 is provided to detect the presence or absence of. If the sensor 14 does not turn on when the tracking length LH becomes equal to the distance L, it is determined that waving has occurred.

[0008]

However, the technique disclosed in the above publication has the following problems.

In estimating the tracking distance LH, the advancement rate is usually determined as a function of the mill rolling reduction rate, and since this rolling reduction rate cannot be actually measured, a calculated value is used. However, since the rolling reduction rate has an error of around 10%, erroneous determination is likely to occur.

[0010] Furthermore, in the hot run table at the exit side of the hot finishing mill, the environment in the water cooling zone is quite bad due to the influence of water vapor and water, making it difficult to accurately detect the steel strip with sensors. be.

Furthermore, even if the steel strip is detected accurately, waving can only be detected after the steel strip reaches the sensor, resulting in a delay in countermeasures.

The present invention has been made to solve the above-mentioned conventional problems, and it is possible to detect the waving of the strip directly and accurately on the line even on a hot run table in a poor measurement atmosphere. The present invention aims to provide a waving detection method.

[0013]

[Means for Solving the Problems] The present invention provides a method for transporting a stop on a pass line so that when the stop is conveyed on a pass line, a water column exceeding The above problem is solved by providing a sonic distance meter, measuring the distance to the strip using the water column ultrasonic distance meter, and detecting the amount of waving of the strip from the measured distance.

[0014]

[Operation] According to the water column ultrasonic distance meter, the distance to the strip can be detected in the water cooling zone of the hot run table without being affected by water vapor or water riding. The present inventor came up with the idea of employing such a water column ultrasonic distance meter for detecting the amount of strip waving.

In the present invention, as shown in FIG. 1, for example, a water column ultrasonic distance meter 22 is provided opposite the strip 12 and at a distance Ho such that it does not come into contact with the waving of the strip 12. The distance l to the strip is measured using the distance meter 22. The waving amount H of the strip 12 from the measured distance l to the strip
Detect w.

Therefore, the amount of waving of the strip can be directly detected without relying on estimation as in the above-mentioned Japanese Patent Publication No. 2-42005, and therefore the amount of waving can be detected with high accuracy.

[0017]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In this embodiment, the amount of waving Hw of a hot-rolled steel strip 12 is detected using a water column ultrasonic distance meter 22 configured as shown in FIG. In addition, in FIG. 1, the symbol T indicates the hot run table of the steel strip 12;
0 indicates that table roll.

As shown in FIG. 1, a water column ultrasonic distance meter 22
is provided facing the steel strip 12 on the line. In addition, in consideration of the threadability of the steel strip 12, they are provided at a distance so that they do not come into contact with each other due to the waving of the steel strip 12. In the embodiment, a water column ultrasonic distance meter 22 is provided at a distance Ho from the hot run table T.

The distance meter 22 also includes a nozzle 26 that emits a water column, and an ultrasonic probe that propagates ultrasonic waves into the water column and measures the distance from the reflected waves, as shown by the broken line in FIG. 24 are provided. This nozzle 26 has the ability to increase the flow velocity as much as possible in order to avoid the influence of disturbances such as splashing water, and also has the ability to radiate a constant water column over a long distance in consideration of the threadability of the steel strip 12. It is necessary. Therefore, in this embodiment, a nozzle 26 having a configuration as shown in FIG. 2 is provided in the water column ultrasonic distance meter 22.

As shown in FIG. 2, the ultrasonic distance meter 22
includes an ultrasonic probe 24 and a nozzle 26.

[0022] The nozzle 26 has a nozzle upper metal fitting 28A.
and a nozzle lower metal fitting 28B, a boss 30 concentrically arranged inside the nozzle cover, a rectifier plate 32, and a water supply pipe 34 fitted from the outside to the side surface of the nozzle cover 28. Equipped with.

Nozzle upper metal fitting 2 of the nozzle cover 28
8A is a cylindrical portion 29A into which the ultrasonic probe 24 is fitted so as to face into the nozzle cover 28;
A conical part 29B inclined toward the outer lower part from the lower end of A;
A second cylindrical portion 29C having a cylindrical shape and hanging downward from the outer end of the conical portion 29B is integrally formed with the conical portion 29B. Note that a water supply hole 29D is formed in the lower part of the second cylindrical portion 29C.
The water supply pipe 34 is fitted into D.

The nozzle lower metal fitting 28B is fixed to the lower end surface of the nozzle upper metal fitting 28A with, for example, a screw member 35 so as to close the lower end surface. Further, a water outlet 36 communicating with the boss 30 is formed in the center of the lower metal fitting 28B. Further, a boss support portion 30 is provided in the water outlet 36 for fitting and supporting the lower part of the boss 30.
A is formed.

The boss 30 has a substantially cylindrical hollow portion 30A formed in its center, with both ends facing the water outlet 36 and the emission side of the ultrasonic probe 24. The boss 30
is a first inclined surface 30B that is inclined outwardly and downwardly from the probe 24 side opening of the hollow portion 30A;
A second sloping surface 30C that slopes inward and downward from the lower end of the slanted surface 30B, and a third cylindrical portion 30D that extends vertically downward from the lower end of the second slanted surface 30C are formed. This third cylindrical portion 30D is connected to the boss support portion 30
Fits into A.

[0026] The baffle plate 32 is connected to the nozzle cover 28.
It is provided between the inner surface and the cylindrical portion 30D of the boss 30 to regulate the flow of water.

An orifice 38 is formed between the inner surface of the nozzle cover upper fitting 28A and the first inclined surface 30B of the boss 30. Further, a pressure equalizing chamber 40 is formed between the inner surface of the metal fitting 28A and the third cylindrical portion 30D.

Therefore, in this nozzle 26, water supplied from the water supply pipe 34 first flows toward the lower part of the pressure equalization chamber 40 through the water supply hole 29D, as shown by the arrow in FIG. After the pressure equalization chamber 40 is completely filled with water, the water is led to the upper orifice 38, turned over, and then injected from the water outlet 36 through the hollow part 30A. At this time, in the pressure equalization chamber 40 having a relatively large cross-sectional area, the pressure of the inflowing water in the circumferential direction is almost uniform, and the flow of water is relatively uniform on the way from the pressure equalization chamber 40 toward the hollow part 30A. By having a long path and passing through the small gap orifice 38, the circumferential pressure of the water is more uniform and laminar.

Therefore, water flows into the hollow portion 30A with uniform pressure in the circumferential direction. As a result, the water outlet 36
The water column injected toward the steel strip 12 has uniform pressure in the circumferential direction and is stable for a long time. Therefore, a desired distance can be maintained between the water column ultrasonic distance meter 22 and the steel strip 12. In addition, since the pressure equalizing chamber 40 is always completely filled with water in an amount commensurate with the amount of water jetted from the water outlet 36, air bubbles are less likely to be generated and it is possible to prevent air bubbles from being drawn into the water column. . Therefore, the ultrasonic probe 24 transmits,
The received ultrasonic signal is not disturbed by noise.

The operation of the embodiment will be explained below.

Using the ultrasonic distance meter 22 according to the embodiment,
As shown in FIG. 1, waving occurring at the tip of the steel strip 12 after hot rolling was detected.

The waving height Hw of the steel strip 12 has a relationship with the detection distance l (L) of the ultrasonic distance meter 22 as shown in FIG. Therefore, the height of the waving (corresponding to the amount of waving) Hw is calculated by the following formula (2
) can be calculated and detected.

[0033] Hw =Ho −l
......(2)

If there is a possibility that the detected waving height Hw may cause trouble in winding, increase the speed of the hot line table or decelerate the finish rolling mill side to flatten the tip and suppress the waving. Plan. As a result, the steel strip 12 is attached to the winding device (not shown).
can be wound normally, and the rolled appearance of the steel strip 12 can be made good.

Here, the relationship between the flow velocity V of the water column and the measurable distance lmax was investigated for each of the nozzle diameters d of 25, 30, and 35 (mm). The survey results are shown in Figure 3.

From this investigation, the nozzle diameter is 25 to 35 (m
It was found that a range of m) is desirable. This nozzle diameter d allows highly accurate waving amount detection within a certain tolerance range. In addition, in order to make the measurable distance 1500 (mm), the nozzle diameter is preferably in the range of 30 to 35 (mm).
In particular, in order to increase the flow velocity of the water column, the nozzle should be
(mm) is more effective. Also, the measurement distance is 1400
(mm) or more, a nozzle with a diameter of 35 (mm) can also be used.

Further, when waving occurs, the angular relationship between the water column and the steel strip is not always 90°, but has a certain inclination angle. The relationship between the inclination angle and measurement error is expressed as nozzle diameter d =
25, 30, and 35 (mm) were investigated. The survey results are shown in Figure 4. As a result of this investigation, the angle of inclination was 4
The nozzle diameter that could be measured up to 5° was only 30 (mm) in diameter. Moreover, the measurement error increased between 15 and 30 degrees of inclination angle.

In the above embodiment, the ultrasonic distance meter 22 was shown as having a nozzle 26 having the configuration shown in FIG. 2, but the configuration of the nozzle is not limited to that shown in the figure. Any nozzle that can spray a water column over a distance is not limited to the configuration shown in the figure. For example, a nozzle as shown in Japanese Patent Application No. 1-58195 filed by the applicant of the present application can be used. Further, a plurality of ultrasonic range finders 22 may be installed.

Furthermore, in the above embodiments, a steel strip was cited as an example of a strip, but the strip in which the amount of waving can be detected in the present invention is not limited to this steel strip. The present invention can also be employed when detecting the amount of waving of a metal strip.

[0040]

[Effects of the Invention] As explained above, according to the present invention, the amount of waving of a strip threaded on a line can be directly detected at high speed and with high precision without being affected by water vapor, water riding, etc. be able to. Therefore, excellent effects such as improved workability in threading, cooling, and winding of the strip, improved rolling efficiency, improved productivity, and improved yield can be obtained.

[0041] Further, the following effects were confirmed through investigation by the present inventor. That is, in the hot rolling line, the plate thickness is 2.0
Waving of a thin steel strip of less than mm was detected by the present invention. In this case, the water column ultrasonic distance meter has a measuring distance of 15
At 00mm, the measurement error is plus or minus 20mm.
Accuracy was obtained. In addition, the threading speed of the thin steel strip (2 mm or less) was set to 720 mpm to suppress waving, and the telescope amount at the tip at this time was 20 mm on average, but with the present invention, the detected waving amount was As a result of changing the threading speed according to the
pm, and the telescope amount was improved to within 10 mm, confirming the usefulness of the present invention in terms of accuracy and productivity.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a configuration in which an ultrasonic distance meter according to an embodiment of the present invention is arranged on a line.

FIG. 2 is a longitudinal sectional view showing the detailed configuration of the nozzle used in the ultrasonic distance meter of the embodiment.

FIG. 3 shows the following diagram for explaining the operation of the embodiment.
FIG. 3 is a diagram showing an example of the relationship between water column length and velocity at various nozzle diameters.

FIG. 4 is a diagram showing an example of the relationship between the error rate and the angle between the water column and the strip.

FIG. 5 is a layout diagram showing an example of a conventional waving detection method.

[Explanation of symbols]

12...Strip (steel strip), 22...Water column ultrasonic distance meter, 24...Ultrasonic probe, 26... Nozzle, 28... Nozzle cover, 28A...Nozzle upper metal fitting, 28B...Nozzle lower metal fitting, 29A...first cylindrical part, 29B...conical part, 29C...second cylindrical part, 29D...Water supply hole, 30...Boss, 30A...Hollow part, 30B...first inclined surface, 30C...second inclined surface, 30D...Third cylindrical part, 32... rectifying plate, 34... Water supply pipe, 36...Water outlet, 38...orifice, 40... pressure equalization chamber, T...Hot run table.

Claims (1)

[Claims] 1. A water column ultrasonic distance meter is provided on the line so as to face the strip when the strip is conveyed on the pass line, and at a distance from which the strip does not come in contact with the waving of the strip. A method for detecting waving of a strip, comprising: measuring the distance to the strip with an ultrasonic distance meter, and detecting the amount of waving of the strip from the measured distance.