JPS6235257A - Ultrasonic flaw detector - Google Patents

Abstract

PURPOSE:To detect a flaw in a thin body, an end surface of a body to be inspected, etc., easily with high precision by making an ultrasonic wave on the body to be inspected at a desired angle of deflection. CONSTITUTION:An ultrasonic wave oscillator 3 delays the driving timing of a micro probe 1a... successively under the control of a delay time controller 7 to transmit ultrasonic waves 2a...2d at an angle alpha of deflection. Those ultrasonic waves enter the body 21 to be inspected from a contact medium 4, and are reflected by a reverse surface 21a, an end surface 21b, or a corner part 21 to enter the medium 4 again and received by the probes 1a.... Then, the ultrasonic waves 2a, 2b, and 2c are received and put together by the probe 1a..., and sent to an ultrasonic wave receiver 5. This receiver 5 performs delay addition 11 by controlling a delay time and the result is supplied to a CRT 13 and a signal processor 15; when there is a defect part, its position is found and the level of the reflected wave from the defect part is found, so that an alarm 19 is outputted by an alarm output device 19.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ultrasonic flaw detection device, and particularly to a device that can accurately and easily detect flaws on the end face of thin objects or plate materials.

[Technical background of the invention and its problems 1] Fig. 4 shows the principle of a conventional ultrasonic flaw detection device.

Ultrasonic waves transmitted from the ultrasonic probe 101 are perpendicularly incident on the object to be inspected 105 via the couplant (for example, water) 103, and if there are defects such as scratches or berries in the object to be inspected, the As shown in the figure, the defective part echo is received.

However, in the conventional device described above, the ultrasonic waves
5, the surface echo S and the back surface echo B
exist, and these surface echoes S.

Defects such as scratches and holes existing near the front surface or the back surface of the object to be inspected 105 cannot be detected by backside echo B, and flaw detection is particularly difficult for thin objects.

In addition, since the ultrasonic waves are perpendicularly incident on the object to be inspected 105,
It was impossible to detect flaws on the end face 107 of the object 105 to be inspected.

Furthermore, in the case of online flaw detection, a separate device is required to make the probe 101 follow the inspected object 105 in response to line fluctuations, and it is also necessary to process many channels in synchronization. The problem was that it was a large scale project.

[1] An object of the present invention is to provide an ultrasonic flaw detection device that can easily perform flaw detection on the end face of a thin object or an object to be inspected with high accuracy.

[Summary of the Invention] In order to achieve the above object, the present invention transmits ultrasonic waves from an ultrasonic probe to an object to be inspected, and detects flaws in the object by receiving reflected waves from the ultrasonic probe with the ultrasonic probe. The gist of the present invention is to provide an ultrasonic flaw detection device in which ultrasonic waves sent from the ultrasonic probe are deflected at a desired angle.

[Embodiment of the Invention] FIG. 1 is a block diagram showing the configuration of an embodiment of an apparatus according to the present invention.

The ultrasonic probe 1 consists of a large number of microprobes 1a, . . . arranged at a predetermined pitch, and a predetermined number of
81! The numbers F and Y are printed in the closed number group.

An ultrasonic oscillator 3 and an ultrasonic receiver 5 are connected to the microprobes 1a, . . . belonging to each of the above groups. These oscillators3. The delay time of the receiver 5 is controlled by a delay time controller 7. That is, under the control of the delay time controller 7, the ultrasonic oscillator 3 controls the microprobes la, .
. . . are sequentially driven with a time difference, so that one beam from each group is electronically deflected so as to transmit ultrasonic waves at a predetermined deflection angle α.

The counterwaves received by the ultrasonic receiver 5 are combined and amplified by an amplifier, and then supplied to a delay adder 11.

In the delay adder 11, the received data is delayed and added under the control of the delay time controller 7, and the added data is stored.

The added data is output to a cathode ray tube (CRT) 13 and a signal processor 15. The cathode ray tube 13 displays the added data in an A scope (A mode image), a B scope (B mode image), or a C scope (C mode image).

The signal processor 15 is configured with a known circuit equipped with a gate circuit, and can calculate the ultrasonic beam path length from the time difference between transmission and reception, the position of the defective part in the object to be inspected 21, and the distance from the defective part. Processing calculations are performed on the level of echoes (defect echoes).

The image display device 17 displays an image of the inspection result of the object to be inspected based on the signal processing result, and an alarm is output from the alarm output device 19 when a defect is detected. In addition,
In the figure, reference numeral 4 denotes a couplant, and a medium such as water or oil is appropriately selected to make it easier for the ultrasonic waves 28 to 2d to enter the object 21 to be inspected.

Next, its effect will be explained.

The ultrasonic oscillator 3 sequentially delays the driving timing of each microprobe 1a, . . . under the control of the delay time controller 7, and emits ultrasonic waves 28 to 28 at a deflection angle α as shown in FIG. 2
Send d. The maximum deflectable angle is determined by the wavelength of the ultrasonic wave in the couplant 4 and the element pitch of the microprobes la, . . . .

The transmitted ultrasonic wave is incident on the object to be inspected 21 at an incident angle β,
Propagates at refraction angle γ. When the ultrasound probe 1 and the test object 21 are arranged in parallel, Zα=Zβ. Further, in order to enhance the resolution function in the distance direction, the incident angle β is preferably selected such that only transverse waves exist in the object 21 to be inspected.

The ultrasonic waves transmitted from each of the probes 1a, . A series of routes are followed in which the signal is received by the probes 1a, . . . .

What is important here is that even if the transmitted ultrasonic waves are received on different paths, the path length is always constant unless there is a defect in the inspected object 21, that is, the propagation time from transmission to reception is constant. That's what it means. For example, ultrasonic waves 2a, 2b, and 2C in FIG. The sound waves 2a, 2b, and 2c are all the same.

Ultrasonic waves 2a, 2b, 2c are ultrasonic probes 1t1°...
・After being received and combined, it is supplied to the ultrasonic receiver 5.

In the ultrasonic receiver 5, the received signals are sequentially delayed under the control of the delay time controller 7, and after these delayed signals are amplified via the amplifier 9, they are supplied to the delay adder 11.

The delay adder 11 performs a delay adder on the received signal and stores it as adder data. The summed data of the received signal is supplied to the cathode ray tube 13 and the signal processor 15. The detection results based on the added data are displayed on the cathode ray tube 13 using a Δscope (A[-mode image), a B scope (B mode image), or a C scope (C mode image).

On the other hand, the signal processor 15 calculates the path length of the ultrasonic beam from the added data. Furthermore, if a defective portion exists, the defect position is determined. Furthermore, the level of reflected waves from the defective portion is determined. These performance results are then displayed on the image display 17. Further, if a defect is detected, an alarm is issued by the alarm output device row 19.

FIG. 3 shows the relationship between the beam path length and the level of the repulsive wave (echo). If there is no defect in the inspected object 21, a reflected wave is always detected at point A in the figure, as shown in FIG. 3 (1). However, if there are scratches or imperfections in the inspected object 21, due to the influence of these defects, the
, (:l) shows that 1-J is received at 8 points or 0 points, which are shifted from the input point. Therefore, if the signal processor 15 83 gates all the ultrasonic waves in the detection range in the object 21 evenly, defects can be detected uniformly.

As explained above, according to this embodiment, ultrasonic waves are obliquely incident on the object to be inspected 21 at a deflection angle α from the ultrasonic probe 1 consisting of a large number of micro probes arranged in an aligned manner to eliminate scratches in the object to be inspected. Since it is configured to detect defects such as cavities, there is no dead zone caused by surface echoes or backside echoes as in the conventional example, and extremely high-precision flaw detection is possible. In addition, a relatively low flaw detection frequency can be used, and the conventional problems such as the need to increase the flaw detection frequency or use a probe with a short pulse width to reduce the dead zone are eliminated.

In addition, by avoiding oblique incidence, the ultrasonic waves can also be emitted to the end surface 21b of the object to be inspected 21, making it easier to detect defects on the end surface 21b, which has been difficult in the past. Extremely effective for flaw detection of pipe plate materials.

Furthermore, by selecting the incident angle β of the ultrasonic waves, only the transverse waves are obliquely incident, so the sound velocity in the object 21 to be inspected becomes slow and the beam path length becomes long. It also becomes possible to perform flaw detection.

In addition, by keeping the deflection angle α of each transmitted ultrasonic wave constant, the propagation path lengths of all the ultrasonic waves become equal, so it is necessary to change the gate position of the gate circuit in the signal processor 15 for each beam. There is no.

In addition, since the reflected wave from the corner 21c of the object 21 to be inspected returns along the same path and is received by the same probe as the transmitting probe, by tracking this corner 21c, flaw detection that follows line fluctuations can be performed. It becomes extremely easy.

In this example, the ultrasonic waves were electronically deflected by controlling the OJ timing of each microprobe 1a of the ultrasonic probe 1. , the ultrasonic wave may be obliquely incident; in this case, the path of the ultrasonic wave may be corrected by the signal processing B 15.

Furthermore, although this embodiment shows a configuration in which a plurality of ultrasonic beams are processed simultaneously, it goes without saying that the same effect can be obtained even if the ultrasonic beams are processed one by one.

Furthermore, it may be a configuration in which electronic scanning is also used in order to improve the resolution.

[Effects of the Invention] As explained above, according to the present invention, since the ultrasonic waves are obliquely incident on the object to be inspected at a desired deflection angle, there is no dead zone caused by the influence of surface echoes or backside echoes. Flaw detection of thin objects and end surfaces of objects to be inspected can be performed easily and with high precision.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of an embodiment of the device according to the present invention, Figs. 2 and 3 are diagrams explaining the operation of the device, and Figs. It is a figure explaining an effect|action. 1... Ultrasonic probe 1a... Micro probe 3... Ultrasonic oscillator 5... Ultrasonic receiver 7... Delay time controller 11... Delay adder 15... Signal processor 21...Object to be inspected Fig. 1 21c 21 Fig. 2 Fig. 3 Fig. 4 View y valley Fig. 5

Claims (3)

[Claims] (1) Send ultrasonic waves from the ultrasonic probe to the object to be inspected,
An ultrasonic flaw detection device that detects flaws on an object to be inspected by receiving reflected waves from transmitted ultrasonic waves with the ultrasonic probe, characterized in that the ultrasonic waves transmitted from the ultrasonic probe are deflected at a desired angle. Sonic flaw detection equipment. (2) The ultrasonic flaw detection apparatus according to claim 1, wherein the ultrasonic probe is formed by dividing a large number of microprobes arranged in an array into groups of a predetermined number. (3) The ultrasonic flaw detection apparatus according to claims 1 and 2, wherein the deflection of the ultrasonic waves is obtained by sequentially delaying the driving timing of the microprobes.