JPS61245055A - Ultrasonic flaw inspecting device - Google Patents

Abstract

PURPOSE:To execute the flaw inspection of various defects of a body to be inspected with high accuracy and at high speed by providing a non focusing type probe, a focusing type prove and an operating means, etc. CONSTITUTION:A defect 2 existing in the inside of a body to be inspected 1 is detected by a rough flaw inspection by the scan of a non-focusing type probe 3 first. At this time point, only the existence of a defect can be brought to a flaw inspection at the high speed. In this case, an ultrasonic beam emitted by a non-focusing type probe use transmitter-receiver 4 is reflected by the defect 2 and the time when it is received by the transmitter-receiver 4 is measured by a propagation time measuring circuit 5. From this propagation time and the sound speed of the ultrasonic wave of the body to be inspected 1, a distance extending from the surface of the body to be inspected 1 to the defect 2 is calculated by a data processor 6. Also, the device 6 calculates the direction and the position of a focus from a distance to the defect 2 and a position relation to the probe 3 of a focusing type probe. In this state, an ultrasonic wave is probe 3 of a focusing type probe. In this state, an ultrasonic wave is transmitted from a focusing type probe use transmitter-receiver 9 and it is received through a probe 7. In this case, by constituting the device so that the focal position of the ultrasonic wave covers a beam width by the probe 3, the defect 2 can be evaluated exactly.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an ultrasonic flaw detection device, and particularly to an ultrasonic flaw detection device suitable for detecting various defects in a specimen with high precision and at high speed. It is.

[Background of the invention]

Conventional ultrasonic flaw detection equipment uses either a non-focused probe or a focused probe (array transducer, etc.) depending on the purpose of rough or precise flaw detection. . Therefore, in the case of rough flaw detection, it was possible to perform flaw detection in a short time, although high precision cannot be expected in evaluating the size of defects. On the other hand, in the case of precision flaw detection, high-precision flaw detection can be expected, but it has the advantage and disadvantage of requiring a large amount of time for flaw detection, and cannot meet the demand for high-precision and high-speed flaw detection. could not.

In addition, as related to this type of device, for example, Japanese Patent Application Laid-Open No. 59-56159, Japanese Patent Application Laid-Open No. 59-60354,
There is a publication.

[Purpose of the invention]

The present invention has been made in view of the above, and its purpose is to provide an ultrasonic echo device No. 7 that can detect various defects in a specimen with high precision and high speed. be.

[Summary of the invention]

The present invention includes a non-focusing probe, a focusing probe, and a calculation means for calculating the position of a defect existing in a subject from the propagation time of an ultrasonic echo detected by the non-focusing probe. and a control means for focusing the focusing probe on the defect position, and the focused focusing probe↓receives the detected ultrasonic echo, and detects the above-mentioned object from this echo signal. and detection means for detecting the size and shape of the defect.

(Embodiments of the Invention) The present invention will be described in detail below with reference to the embodiments shown in FIGS. 1, 3FM, and 6, as well as FIGS. 2, 4, and 5.

FIG. 1 is a basic configuration diagram showing an embodiment of the ultrasonic flaw detection apparatus of the present invention. In FIG. 1, a defect 2 existing inside an object 1 is first detected by rough flaw detection by scanning with a non-focusing probe 3.

At this point, the beam from the unfocused probe 3 can be damaged. Here, the propagation time measurement circuit 5 measures the time from when the ultrasonic beam emitted by the non-focusing probe transceiver 4 is reflected by the defect 2 until it is received by the transceiver 4. The data processing device 6 calculates the distance from the surface of the object 1 to the defect 2 based on this propagation time and the sound speed of the ultrasonic wave of the object 1 . The data processing device 6 also calculates the distance to the defect 2 and the focusing probe (
The direction and position of the focal point are calculated based on the positional relationship of the non-focusing probe 3 (a -dimensional array transducer is used here), and the delay time for each probe of the focusing probe 7 (
τ1. τ2. ...τ, )8 is set. In this state, ultrasonic waves are transmitted from the focusing probe transceiver 9, and reflected ultrasonic waves are received via the focusing probe 7. When transmitting and receiving ultrasonic waves, if the delay time 8 is constantly changed so that the focal position of the ultrasonic waves covers the ultrasonic beam width by the non-focusing probe 8, and the ultrasonic waves are repeatedly transmitted and received, the shape of the defect 2 can be evaluated accurately.

Therefore, by using a non-focusing probe 3 with a somewhat wide beam width, it is possible to perform rough flaw detection at high speed. Evaluation can be carried out.

FIG. 2 is a diagram showing the time relationship between the transmitted signal and the reflected wave received signal in FIG. 1.

The distance from the unfocused probe 3 to the defect 2 obtained by rough flaw detection is determined by the propagation time T (second
(see figure) and the sound speed C in the object 1.

It can be calculated by The delay time T at this time can be measured, for example, by the propagation time measuring circuit 5 having the configuration of the embodiment shown in the third wR. In Fig. 3, 3 is a non-focusing type probe, 4 is a transceiver for a non-focusing type probe, and 5 is a propagation time measuring circuit, which defocuses the ultrasonic waves from the transceiver for a non-focusing type probe 4. At the time of transmission to the type probe 3, the counter circuit 51 starts counting the pulse signals from the clock pulse generation circuit 52, and the ultrasonic signal reflected from the defect 2 (see Fig. 1) is transmitted to the non-focused type probe 3. Probe transceiver 4
After that, AGC (Automatic Galn C)
control) circuit 53 and amplifies the signal to a predetermined amplitude, the reflected wave detection port l! 54, when the predetermined amplitude vt is exceeded, a counter stop signal is sent from the reflected wave detection circuit 54 to the counter circuit 5, causing the counter circuit 51 to stop counting clock pulses. By the propagation time measurement circuit 5 having such a configuration, the propagation time T of the ultrasonic wave is
A count value proportional to can be obtained. Note that the frequency of the clock pulse generated by the clock pulse generation circuit 52 is determined depending on the measurement accuracy of the distance from the non-focusing probe 3 to the defect 2.

FIG. 4 is a time chart of typical input/output signals of each part in FIG.
The amplified signal 53a, (a) of the reflected wave from the C circuit 53 is the counter stop signal 54a, (d) from the reflected wave detection circuit 54.
) is a clock pulse signal 52a from the clock pulse generation circuit 52. The counter circuit 51 starts counting the pulses of the clock pulse signal 52a from time t1 when the pulse of the count start signal 4a is input, and counts the clock pulses until time t2 when the pulse of the count stop signal 54a is input. .

If the distance from the non-focusing probe 3 to the defect 2 is determined by equation (1), then the distance between the non-focusing probe 3 and the focusing probe 7 is
Assuming that the positional relationship between and defect 2 is as shown in Figure 5, the delay time τ, (i = 1 to n) of each array transducer used in the focusing probe 7 is as follows. It can be determined as follows.

Here, the number of array transducers is n, the distance from the center of the focused probe 7 to the center of the non-focused probe 3 is D, the diameter of the non-focused probe 3 is d, and the focal position is P. , , the horizontal distance from the center of the focusing probe 7 to the focal point P is Xo, and the position of the array probe is x1 to X, respectively, with the center of the focusing probe 7 as zero. If the pitch interval is P, then i
The digit 1 of the th array transducer! The positions xll of xi, focal position IIP, and focal position IIP are expressed by the following equations.

X, = L tan θa −(3
) here, θ. ;Angle L between the perpendicular from the center of the focusing probe 7 and a line connecting the focal point MPF;Depending on the vertical distance from the center of the focusing probe 7 to the focal point Wt P F, the i-th array vibration The beam path length Q1 of the ultrasonic waves transmitted from the child in the subject 1 is nt=57τX,)
"+L"...Represented by (4). Therefore, if the beam path length of the first array transducer is used as a reference, the path length difference Δg, (i=1 to n) and delay time τ of each array transducer are as follows: ,Ha,
=! It is shown as Σ;-5〽a;...(5).

In this way, the vertical pressure JII to the focus position Pv of defect 2
L and the focal position of the defect 2 from the center of the focusing probe 7 [P,
Horizontal distance to X. From the relationship with the sound velocity C in the object 1, the ultrasonic beam can be set at the focal position 1 by setting the delay time τ for each array transducer determined by equation (6).
It is possible to focus on p v.

If the flaw detection direction is set to the right as shown in FIG. 5, the reflected wave is first received by the non-focusing probe 3 as
This almost corresponds to the leftmost edge of defect 2.

Therefore, the precision flaw detection range using the focusing probe 7 is as follows:
At the depth L of the object 1, the focal point P of the ultrasonic beam is X, <X<X, +ΔX+7).
The size and shape of the defect 2 can be precisely measured.

In this case, the non-focusing probe 3 and the focusing probe 7 are separated by an interval and scanned as a unit, and the non-focusing probe 3 is scanned without moving from the location where the defect 2 is detected. The method of scanning the ultrasonic beam using the one-dimensional array sensor of the focusing probe 7 has been described, but if the depth L of the defect 2 is small, the beam incidence angle θ by the focusing probe 7 will change. may become too large. In such a case,
After moving the center of the focusing probe 7 to the position where the defect 2 is detected, the ultrasonic beam is scanned in a fan shape within the range of focal length R < R < L + ΔL before flaw detection is performed. However, the focal length change range ΔL should be set in advance based on the expected size of the defect 2.

According to the embodiment of the present invention described above, there is an advantage that it is possible to evaluate defects 2 with high accuracy and at high speed even for the object 1 whose flaw detection area is wide.

In the above embodiment, a one-dimensional array transducer was used as the focusing probe 7, but the sixth embodiment
As shown in the figure, a plurality of focusing probes 71-7. each have a fixed focal length. As in the case of using an array transducer, the distance to defect 2 is calculated from the propagation time of the ultrasonic wave to defect 2 obtained by the non-focusing probe 3, and the distance to defect 2 is calculated based on the data. 7. A focusing probe with a focal length matching the distance to 7. The size, shape, etc. of the defect 2 may be detected with high precision by selecting the selected focusing probe 71 using the probe switching device 10 and positioning the selected focusing probe 71.

〔Effect of the invention〕

As explained above, according to the present invention, there is an effect that various defects in a test object can be detected with high precision and at high speed.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram showing an embodiment of the ultrasonic flaw detection device of the present invention, FIG. 2 is a diagram showing the time relationship between the transmitted signal and the reflected wave reception signal in FIG. 1, and FIG. Figure 4 is a time chart of typical input/output signals of each part in Figure 3. Figure 5 is a block diagram showing an example of the propagation time measurement circuit shown in Figure 3. FIG. 6 is a diagram illustrating the relationship among the probe, the defect, and the focal position of the ultrasonic beam, and is a basic configuration diagram illustrating another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Object, 2... Defect, 3... Unfocused probe, 4... Transmitter/receiver for non-focused probe, 5... Propagation time measurement circuit, 6... - Data processing device, 7... Focusing type probe, 8... Delay circuit, 9... Transmitter/receiver for focusing type probe. 10... Probe switching device, 51... Counter circuit, 5
2... Clock pulse generation circuit, 53... AGC circuit. 2nd opening '$ 3rd day + opening 'yfJs closing i

Claims (1)

[Claims] 1. In an ultrasonic flaw detection device for detecting various defects present in metal materials, there is a non-focusing probe, a focusing probe, and a defect detected by the non-focusing probe. a calculation means for calculating the position of a defect existing in the object from the propagation time of an ultrasonic echo; a control means for focusing the focusing probe on the defect position; and a focusing probe for focusing the focusing probe on the defect position. 1. An ultrasonic flaw detection apparatus comprising: a detecting means for receiving an ultrasonic echo detected by the above-described method, and detecting the size and shape of the defect in the object from the echo signal. 2. The focused probe uses a plurality of array transducers whose delay time can be changed depending on the propagation time of the ultrasonic echoes detected by the non-focused probe. Ultrasonic flaw detection equipment. 3. The focusing probe is composed of a plurality of focusing probes having different focuses, and the control means is configured to adjust the focusing probe according to the propagation time of the ultrasonic echo detected by the non-focusing probe. The ultrasonic flaw detection apparatus according to claim 1, further comprising probe switching means for switching between focusing probes.