JPH05149929A - Ultrasonic flaw detecting apparatus for band plate - Google Patents

Abstract

PURPOSE:To make it possible to perform high-speed scanning of ultrasonic probes without bending the pass line of a band plate. CONSTITUTION:Upper and lower sealing pinch rolls 32, which prevent liquid leakage, hold a band plate 10 and maintain the pass line of the plate approximately horizontally, are provided at the input side and the output side of a liquid tank 30. The band plate 10 is continuously submerged into the liquid in the water tank 30. At least the tips of ultrasonic probes 16 and 17 are dipped into the liquid in the water tank 30. Ultrasonic waves are cast into the direction of the thickness of the band plate 10, which is submerged into the same liquid, from the ultrasonic probes 16 and 17. The ultrasonic probes 16 and 17 are scanned in the direction of the thickness of the band plate 10 with scanning mechanisms 36 and 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flaw detector for a strip plate, and more particularly to a continuous flaw detector suitable for on-line ultrasonic flaw detection of a steel strip that is continuously passed. The present invention relates to an improvement of an ultrasonic flaw detector for a strip-shaped plate that performs flaw detection by injecting ultrasonic waves in the thickness direction of the strip-shaped plate to be formed.

[0002]

2. Description of the Related Art As a method for transmitting and receiving ultrasonic waves in the plate thickness direction of a steel strip which is continuously passed, as shown in FIG.
Water 14 is jetted toward the lower surface of the steel strip 10 to form a water column extending from the nozzle 12 to the lower surface of the steel strip 10, and ultrasonic waves are introduced into the water column from an ultrasonic probe 16 arranged upward in the nozzle 12. A method is known in which a beam 18 is incident and an ultrasonic wave is propagated to the steel strip 10.

According to the ultrasonic flaw detector using such a water column, ultrasonic waves can be efficiently transmitted / received to / from a continuously running steel strip.

[0004]

However, when the ultrasonic probe and the water column are scanned in the plate width direction for flaw detection, if the scanning speed is high, the shape of the water column is disturbed due to air resistance, etc. Ultrasonic waves may not be transmitted and received accurately. Therefore, there is a problem that the scanning speed is limited and high-speed scanning cannot be performed.

On the other hand, when detecting an individual plate instead of a strip, the plate is immersed in a water tank and ultrasonic waves are incident downward from an ultrasonic probe arranged above the plate. .

When this water immersion method is applied to ultrasonic flaw detection of a steel strip running online, as shown in FIG.
A part of the pass line of the steel strip 10 is bent downward by the deflector 22 and immersed in the water 14 in the water tank 20, and the ultrasonic probe 1 is arranged downward near the water surface of the water tank 20.
It is conceivable that the ultrasonic beam 18 is incident from the position 6.

However, with this method, it is necessary to change the pass line of the current line, and it is not easy to install it on the existing line. Furthermore, when the pass line is changed, tension is applied to the deflector roll 22, so a small-diameter roll cannot be used, and the horizontal distance between the deflector rolls 22 in the ultrasonic measurement portion becomes large, resulting in variation of the pass line. However, there is a problem in that high precision measurement cannot be performed.

The present invention has been made to solve the above-mentioned conventional problems, and suppresses the change of the pass line of the ultrasonic measurement portion without changing the pass line of the current line,
An object of the present invention is to provide an ultrasonic testing device for a strip-shaped plate, which enables high-accuracy online measurement while performing high-speed scanning.

[0009]

According to the present invention, liquid leakage is prevented in an ultrasonic flaw detection apparatus for a strip-shaped plate that performs flaw detection by injecting ultrasonic waves in the plate thickness direction of the strip-shaped plate that is continuously threaded. While sandwiching the strip plate, to keep the pass line substantially horizontal, upper and lower sealing pinch rolls are respectively provided on the inlet side and the outlet side, the strip plate is continuously immersed in the liquid. A liquid tank to be immersed, an ultrasonic probe at least the tip of which is immersed in the liquid in the liquid tank, and an ultrasonic probe for injecting ultrasonic waves in the plate thickness direction of the strip-shaped plate immersed in the same liquid; The above object is achieved by including a means for scanning the acoustic probe in the plate width direction of the strip plate.

[0010]

In the present invention, the inlet side and the outlet side of the strip plate are divided into two.
The book is pinched by a pinch roll for sealing to prevent liquid leakage from the liquid tank. Therefore, the strip plate can be continuously immersed in the liquid in the liquid tank without changing the pass line of the current line.

Therefore, at least the tip of the ultrasonic probe is
By immersing in the liquid in this liquid tank, ultrasonic waves can be transmitted and received efficiently.

Further, the ultrasonic probe can be scanned at high speed in the width direction of the strip plate.

Further, since it is not necessary to change the pass line of the current line, it can be easily installed on the existing line. Furthermore, since the pass line is almost horizontal, tension is not applied to the seal pinch rolls on the inlet side and the outlet side, it is possible to use a small diameter roll, and the distance between the pinch rolls can be shortened for ultrasonic measurement. It is possible to suppress the variation of the pass line in a part.

In particular, when the liquid tank is constantly filled with a liquid commensurate with the amount of leakage liquid from the periphery of the pinch roll to retain the liquid in the liquid tank, the sealing performance around the pinch roll is improved. Is not very expensive and is economical.

When an ultrasonic wave reflecting plate is provided on the bottom surface of the liquid tank, the ultrasonic waves that have passed through the band-shaped plate are re-incident on the band-shaped plate, and the intensity of multiple reflected waves can be increased.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

In the first embodiment of the present invention, as shown in FIG. 1, the inlet side and the outlet side of the steel strip 10 with respect to the water tank 30 are
Seal with two pinch rolls for sealing,
With respect to the lower portion and the end surface of the sealing pinch roll 32,
A water tank 30 having a gap of about 0.5 mm is installed.

By constantly injecting a water amount exceeding the amount of water leaking from the gap between the water tank 30 and the sealing pinch roll 32 into the water tank 30, the water level 30A in the water tank 30 is increased.
Hold.

As shown in FIG. 2, an ultrasonic reflection plate 34 is disposed on the bottom surface of the water tank 30. The ultrasonic beam 18 passing through the steel strip 10 is re-incident on the steel strip 10 to generate multiple reflected waves. It is designed to increase strength.

The ultrasonic probe 16 is provided on the water tank 30.
Is arranged so that the tip facing downward is immersed in the water in the water tank 30.

As shown in FIG. 3, the ultrasonic probe 16 is scanned by the scanning mechanism 36 over the entire measurement range in the plate width direction in consideration of the meandering of the steel strip 10.

The principle of flaw detection by the ultrasonic probe 16 is, for example, Japanese Patent Laid-Open No. 1-22 proposed by the applicant.
9962 can be used to measure the crystal grain orientation distribution of a silicon steel sheet.

In this case, the difference in crystal orientation can be determined by measuring the difference in intensity of the multiple reflected waves.

Next, the second embodiment of the present invention will be described in detail.

The second embodiment is similar to the first embodiment in that the ultrasonic probe 1 is scanned over the entire width of the steel strip 10.
6, an ultrasonic probe 17 for scanning the edge portion of the steel strip 10 at high speed in a small scanning range is added.

The ultrasonic probe 17 for the edge portion is scanned as shown in FIG. 5, for example.

In the present embodiment, since the edge portion of the steel strip 10 in which the abnormal portion is likely to exist in the steel strip 10 can be scanned at high speed, flaw detection of the abnormal portion can be performed with higher accuracy. it can.

In each of the examples, the ultrasonic waves were made to pass through water, but the type of liquid to be passed through the ultrasonic waves is not limited to this, and for example, other trace components may be added to water. It can be used as a pottery or other liquid can be used.

In each of the above examples, the crystal orientation of the steel sheet was measured, but the object to be measured is not limited to this, and when measuring other defects or abnormal parts of other strips. However, the present invention is applicable.

[0030]

As described above, according to the present invention, the liquid tank can be installed without changing the pass line of the strip plate, and the ultrasonic flaw detector can be easily installed on the existing line.

Further, since the pass line is substantially horizontal, it is possible to use a small diameter roll as the pinch roll for sealing.
Since the distance between the pinch rolls can be shortened, it is possible to suppress the pass line fluctuation in the ultrasonic measurement portion to be small. That is, in the online measurement, in order to ensure the measurement accuracy, it is necessary to prevent the sensitivity from decreasing, and for that purpose, it is necessary to suppress the fluctuation of the pass line and the inclination of the strip plate, but according to the present invention, it is sufficient. Can satisfy this.

Further, unlike the water column method, there is no influence of the turbulence of the water column due to scanning, so that high speed scanning is possible.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the configuration of the measurement system in the first embodiment.

FIG. 3 is a plan view showing a scanning pattern of the ultrasonic probe according to the first embodiment.

FIG. 4 is a perspective view showing a configuration of a second embodiment of the present invention.

FIG. 5 is a plan view showing a scanning pattern of an ultrasonic probe for edge measurement according to a second embodiment.

FIG. 6 is a cross-sectional view showing the configuration of a conventional water column type ultrasonic flaw detector.

FIG. 7 is a cross-sectional view showing an example in which a water tank is installed by bending a pass line of a strip plate.

[Explanation of symbols]

 10 ... Steel strip, 14 ... Water, 16, 17 ... Ultrasonic probe, 18 ... Ultrasonic beam, 30 ... Water tank, 30A ... Water level, 32 ... Sealing pinch roll, 34 ... Ultrasonic reflecting plate, 36, 37 ... scanning mechanism.

Claims (3)

[Claims] 1. An ultrasonic flaw detector for a strip-shaped plate, which performs ultrasonic flaw detection by injecting ultrasonic waves in the plate thickness direction of a strip-shaped plate that is continuously threaded, sandwiching the strip-shaped plate while preventing liquid leakage. , A liquid tank in which upper and lower sealing pinch rolls for holding the pass line substantially horizontally are provided on the inlet side and the outlet side, respectively, for continuously immersing the strip plate in the liquid, and at least the tip. Is immersed in the liquid in the liquid tank, and an ultrasonic probe for injecting ultrasonic waves in the plate thickness direction of the strip-shaped plate immersed in the same liquid; An ultrasonic flaw detector for a strip-shaped plate, comprising: means for scanning in the plate width direction. 2. The liquid according to claim 1, wherein a liquid corresponding to the amount of liquid leaked from the periphery of the pinch roll is constantly injected into the liquid tank,
An ultrasonic flaw detector for a strip-shaped plate, characterized in that the liquid level in the liquid tank is maintained. 3. An ultrasonic flaw detector for a strip plate according to claim 1, wherein an ultrasonic reflection plate is provided on the bottom surface of the liquid tank.