JPS6157573B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ultrasonic flaw detection apparatus that performs ultrasonic flaw detection of defects in a material at high speed.

[Technical background of the invention and its problems]

Conventionally, there has been a flaw detection device that generates an ultrasonic beam by pulse-exciting multiple ultrasonic transducers with an appropriate time delay, and can arbitrarily control the radiation direction of the generated ultrasonic beam. be. When receiving reflected waves from within a material due to ultrasonic beam radiation using the same ultrasonic transducer used for transmitting the waves, this device uses The received reflected waves are added together and the signals are processed. Therefore, for the addition after the reflected waves are delayed, an analog addition method using a delay element or the like is usually used. However, in order to delay the ultrasonic waves reflected from within the material for an arbitrary period of time, it is necessary to combine a large number of delay elements, which inevitably complicates the circuit configuration. It is practically difficult to delay ultrasound for an arbitrary period of time.

[Purpose of the invention]

In view of the above-mentioned circumstances, the present invention provides an ultrasonic flaw detector that speeds up inspection of defects in materials and improves defect detection accuracy by controlling only the timing of ultrasonic wave transmission without delaying the reception of reflected waves. The purpose is to provide equipment.

[Summary of the invention]

The feature of the present invention is that it has a plurality of ultrasonic transducers arranged to form an ultrasonic probe, and any plurality of these transducers are pulse-excited with a delay time to generate ultrasonic waves. Equipped with an ultrasonic generator to
In an ultrasonic flaw detection device in which this ultrasonic wave is emitted in a preset direction within the tested material,
Simultaneous detection of reflected waves from inside the material to be tested using multiple ultrasonic transducers located at positions where they can receive reflected waves such that the propagation distance difference △ with respect to the wavelength λ of the reflected waves satisfies the condition △<λ/4. do what you can,
By controlling only the ultrasonic transmission timing, there is no delay time in receiving reflected waves, speeding up inspection of defects in materials and improving defect detection accuracy.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a configuration diagram according to an embodiment of the present invention. In the figure, an ultrasonic probe 1 includes a plurality of ultrasonic transducers 2 ₁ to 2 _o arranged at equal intervals.
It is integrally composed of. Each of the ultrasonic transducers 2 ₁ to 2 _o is connected to a radiation wave transmitter 3 ₁ to 3 _o for generating ultrasonic waves, and converts the signal from the transmitter 3 into an ultrasonic wave to transmit the material to be tested. send it inside. A trigger signal generator 8 is provided via a trigger signal changeover switch 9 to provide a trigger signal of a predetermined period to the transmitter 3 . This trigger signal generator 8 has an arbitrary delay time set by a control signal from a signal controller 10, and trigger signals generated according to the delay time are sequentially applied to a trigger signal changeover switch 9. This changeover switch 9 arbitrarily selects a trigger signal having a delay time based on the control signal of the signal controller 10 applied at the same time, and applies it to the corresponding arbitrary plurality of transmitters _{3 .} The transmitter 3 used at the time can be selected. In this way, an ultrasonic transmission system to the ultrasonic probe 1 is configured. Further, each of the ultrasonic transducers 2 ₁ to 2 _o is connected to limiters 4 ₁ to 4 _o , respectively. After the high voltage of the signal received by the vibrator 2 is cut off via a limiter 4, the signal is sent to a reception signal selector switch 5.
given to. This changeover switch 5 is simultaneously given a control signal from a signal controller 10, and by arbitrarily selecting the output of the limiter 4, can select a predetermined ultrasonic transducer 2 when receiving a corresponding ultrasonic wave. It is. The arbitrary number of limiter outputs selected by the changeover switch 5 are combined into one signal, and then given to the reflected wave receiver 6, where the signal is amplified. The signal amplified by the receiver 6 is given to a signal processor 7 to extract an electrical signal corresponding to the ultrasonic propagation distance, etc.
The dimensions of defects in the material are recorded and displayed. In this way, an ultrasonic reception system from the ultrasonic probe 1 is configured.

The present invention includes a signal controller 10, and the control signal output from the signal controller 10 is transmitted to the reception signal changeover switch 5 and the trigger provided at the input/output end positions of the ultrasonic reception and transmission system as described above. It is applied to the signal changeover switch 9 to control the signal selection operation by each switch, and is further applied to the signal processor 7, and the reflected wave signal processed by the signal processor 7 is sent to the recording display 11. It is characterized by controlling the transmission of signals at the same time.

Based on the ultrasonic flaw detection device configured as described above, Fig. 2 shows the ultrasonic wave generation in the transmitting system, and Fig. 3 shows the signal processing of reflected waves in the receiving system in relation to the transducer. be. Therefore, the first
An embodiment of the present invention will be described with reference to FIGS.

The signal controller 10 applies a control signal 22 to the trigger signal changeover switch 9 to select the radiation wave transmitters 3 ₁ to 3 _i , thereby selecting an arbitrary number of ultrasonic transducers 2 ₁ to 2 _o for wave transmission. Vibrators 2 ₁ to 2 _i are selected. Also, at this time, the signal controller 10 controls the delay time △
A control signal 23 having T ₁ to ΔT _j-1 is applied to the trigger signal generator 8 . This causes the trigger signal generator 8
is the frequency 1 ~ according to the delay time △T ₁ ~ △T _i-1
A group of trigger signals 15 (FIG. 2a) having a time interval of 10 KHz is generated. After these signals 15 are repeatedly sent to the wave transmitting transducers 2 1 to 2 _i via the trigger signal changeover switch 9 and the transmitters 3 _{1 to} 3 _i , the signals 15 are transmitted to the transducers 2 1 to ₂ i as shown in FIG. An ultrasonic beam 13 that can be focused on the internal defect 16 of the material 14 to be detected is emitted from ~ _2o . After the ultrasonic beam 13 is emitted in this way,
The ultrasonic waves reflected from the internal defect 16 can generally be received by the same transducers 2 ₁ to 2 _i as used for transmitting waves. However, when the oscillators 2 ₁ to 2 _i are used as receiving oscillators to receive reflected waves, the reflected waves 17 ₁ cause a phase shift 18 as shown in FIG. 3a.
~17 _i will be accepted with a delay time from each other. Therefore, in the present invention, a plurality of receiving transducers 2 are particularly selected from the transmitting transducers 2 ₁ to 2 _i to simultaneously receive reflected waves without delay time. be.

In the ultrasonic receiving system according to the present invention, the transducer 2 for receiving reflected waves is located at the center of the transducers 2 ₁ to 2 _i for transmitting waves, and the delay time of the reflected waves received between the transducers is That is, a plurality of transducers 2 with a small phase shift such that the propagation distance difference Δ is Δ<λ/4 or less with respect to the wavelength λ of the ultrasonic wave are selected. In particular, the signal controller 10 provides a control signal 24 corresponding to the ultrasonic flaw detection angle θ to the reception signal changeover switch 5 based on the preset inter-oscillator distance d and the wavelength λ. wave oscillator _2k
~ _2n is automatically selected. Therefore, the reflected waves 17 _k to 17 _n received by the oscillators 2 _k to 2 _n obtained via the limiters 4 _k to 4 _n are simultaneously added without any delay time, and the reflected waves 19 after addition are immediately added. can be formed into

The reflected waves 19 thus simultaneously added are amplified by the reflected wave receiver 6 and then sent to the signal processor 7. At this time, the signal controller 10 outputs a signal 25 corresponding to the angle of the emitted ultrasonic beam.
and a signal 26 corresponding to the positions of the selected wave receiving transducers _2k to _2n are given to the signal processor 7. As a result, the signal processor 7 selects a gate 20 in a range corresponding to the ultrasonic propagation time required to travel back and forth to the flaw detection area.
The threshold level 21 is selected, and the addition reflected wave 19 is calculated. As a result, a signal indicating the height and position of the reflected echo when the added reflected wave 19 exceeds the threshold level 21 is sent to the recording display 11. The recording display 11 displays the position, shape, and other dimensions of the internal defect 16 on a cathode ray tube or the like based on the signal from the processor 7, and also records it on a recording paper or the like.

In the above-mentioned embodiment, ultrasonic flaw detection related to the combination of the wave transmitting transducers 2 ₁ to 2 _i and the wave receiving transducers 2 _k to 2 _n was explained, but other wave transmitting and receiving transducers 2 Similarly, ultrasonic flaw detection can be carried out by changing the selection and combination of the above. A program related to the selection of the wave transmitting/receiving transducer 2 is set in the signal controller 10 in advance. Each time a flaw detection test using a set of vibrators 2 is completed, a completion signal 27 is sent from the signal processor 7 to the signal controller 10. As a result, the signal controller 10, for example, when the flaw detection inspection according to the above-described embodiment is completed, next transmits the transducers 2 ₂ to 2 _i+1 and receives the transducers 2 _k+
If new transducers are selected and combined by moving the wave transmitting/receiving vibration pieces 2 one by one, such as from ₁ to 2 _n+1 , the combinations can be sequentially switched and super Can be used for sonic flaw detection. Once the flaw detection has been completed for all the vibrators 2 ₁ to 2 _o in this manner, the flaw detection may be repeated again starting from the vibrators 2 ₁ to 2 _i . Furthermore, if a program for changing the ultrasonic radiation angle is set in advance in the signal controller 10, after the flaw detection test by switching the vibrator 2 is completed, the flaw detection test can be performed by changing the radiation angle. Therefore, by the above-described flaw detection inspection, internal defects in the material to be flawed can be detected more clearly and in detail.

In addition, although the above-mentioned Example demonstrated the case where the ultrasonic beam was focused and radiated, the present invention can also be applied to the case where the ultrasonic wave is emitted as a parallel beam for flaw detection. That is, if the defective surface is substantially orthogonal to the emitted parallel ultrasonic beam, the waves reflected by the defective surface will also become parallel beams and will be received with Δ=0.

Furthermore, if the program capacity of the signal controller is increased using a computer or the like, internal defects in the material, the shape of the back surface of the material, etc. can be detected by various flaw detection methods. For example, when a reflected echo from an internal defect in a material is detected, the focus of the ultrasonic wave is made to match the detection position of the reflected echo,
By inspecting the material from each direction, the accuracy of detecting the shape, size, etc. of internal defects can be further improved.

Furthermore, in the above-described embodiments of the present invention, the one-probe method was explained in which the transducer for transmitting and receiving is shared, but the transducer is divided into transducers for transmitting and receiving, and a dedicated vibrator is used for each. The present invention can also be applied to a device employing the so-called two-probe method in which subgroups are arranged.

〔Effect of the invention〕

As described above, the present invention uses a plurality of ultrasonic transducers arranged at equal intervals, and controls the ultrasonic transducers by considering only the timing of ultrasonic wave generation from the transducer. The ultrasonic waves received by the receiving transducers that are automatically selected according to various parameters are added simultaneously without any delay time, and the combination of the transmitting and receiving transducers can be combined simultaneously. Since the switching is performed electrically sequentially, there is no need for complex signal processing, and various types of ultrasonic flaw detection, such as changing the focal position of the ultrasonic beam and changing the ultrasonic radiation angle by switching the transducer, are made easier and faster. At the same time, it is possible to improve defect detection accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a configuration example according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating an embodiment of a transmission system according to the present invention. FIG. 3 is a diagram showing the radiation state of the ultrasonic beam, and FIG. 3 is a diagram explaining an embodiment of the receiving system according to the present invention, where a is the received signal between the transducers shown in FIG. 2 b, and b is the receiving vibration. A diagram explaining an example of child selection,
c is a diagram illustrating signal processing of reflected waves. 1... Ultrasonic probe, 2... Ultrasonic transducer, 13...
Ultrasonic beam, 14... Material to be tested, 15... Trigger signal group, 16... Defect in material, 17... Vibrator received signal,
18... Phase shift, 19... Added reflected wave signal, 20
...Gate, 21...Threshold level, 22-2
7...Control signal, △...Ultrasonic propagation distance difference, θ...Flaw detection angle, d...Distance between ultrasonic transducers.

Claims (1)

[Claims] 1. An ultrasonic probe has a plurality of ultrasonic transducers arranged to form an ultrasonic probe, and any plurality of these transducers are pulse-excited with a delay time to generate ultrasonic waves. In an ultrasonic flaw detection device that is equipped with an ultrasonic wave generator that generates an The ultrasonic transducer is characterized in that simultaneous detection is possible by a plurality of the ultrasonic transducers located at positions where the propagation distance difference Δ satisfies the condition that Δ<λ/4 for the wavelength λ. Sonic flaw detection equipment. 2. In the device according to claim 1,
The ultrasonic transducer for receiving reflected waves can be automatically selected based on parameters such as the ultrasonic flaw detection angle, the distance between the arranged ultrasonic transducers, and the wavelength of the ultrasonic waves. Sonic flaw detection equipment. 3. In the device according to claim 1,
The ultrasonic transducer used as a set for transmitting and receiving waves is characterized in that the combination is electrically switched sequentially to enable continuous ultrasonic flaw detection. Ultrasonic flaw detection equipment.