JPH0343586B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for non-destructively inspecting the inside of a material using ultrasonic waves.

[Conventional technology]

As a means of finding defects in solid objects such as metals, ultrasonic waves are injected into the material, and the reflected waves from the defects (hereinafter referred to as echoes) are captured and displayed on a display such as a CRT to determine the size of the defect and the material. There is an ultrasonic flaw detector as a device for measuring the position of defects inside.

Conventionally, an ultrasonic flaw detection device as shown in FIG. 4 has been proposed as this type of device. In the figure 1
2 is a synchronization section that outputs synchronization signals necessary for each circuit;
3 is a transmitter that generates a transmission signal based on the output signal from the synchronizer 1, and 3 is a transmitter that generates an ultrasonic wave based on the transmitter signal from the transmitter 2 and makes the ultrasonic wave enter the material to be inspected. A probe captures an echo from the material and converts it into an electrical signal; 4 is a receiver that amplifies the electrical signal from the probe 3; and 5 is a display that displays the output signal of the receiver 4.

Since the conventional ultrasonic flaw detection apparatus is configured as described above, flaw detection is performed by applying a transmission signal from the transmitter 2 to the probe 3 at a fixed transmission frequency and transmission wave number.

[Problem that the invention seeks to solve]

Conventional ultrasonic flaw detection equipment only transmits at a fixed transmission frequency and wave number as mentioned above, so it uses only one arbitrary point that is limited to the frequency characteristics of the probe. It was not possible to transmit the optimum transmission frequency and transmission wave number for the material to be tested, so it was necessary to replace the probe using only the nominal frequency displayed on the probe as information. A probe with a nominal frequency close to the frequency was selected. However, there is no way to select the number of transmitted waves, and the main body of the ultrasonic flaw detection device that generates an arbitrary number of waves is converted, but there are limits to the types of probes and devices, and in reality, the number of waves is austenitic. Reflected waves from particles that occur during inspection of materials or flaw detection of materials with coarse particles (this is called a gory echo, which worsens the S/N on the display) degrades the S/N. ing.

This invention was made to solve these problems, and includes a frequency variable means and a wave number variable means to find the optimum frequency for the material to be inspected, transmit at the optimum frequency, and select the wave number to obtain the optimum frequency. NaS/
The purpose of this invention is to obtain an ultrasonic flaw detection device that can detect flaws using N.

[Means for solving problems]

The ultrasonic flaw detection apparatus according to the present invention is provided with a frequency variable circuit and frequency setting means for varying the transmission frequency, and a wave number variable circuit and wave number setting means for varying the number of transmitted waves.

[Effect]

In this invention, by varying the transmission frequency and the number of transmission waves and performing transmission optimally for the material to be inspected, it is possible to reduce the factors that cause blemish-like echoes, which worsen the S/N of flaw detection, and facilitate flaw detection. can be done.

〔Example〕

FIG. 1 is a diagram showing an embodiment of an ultrasonic flaw detection apparatus according to the present invention. In FIG. 1, 1 to 5 are the same as those shown in FIG. 6 is synchronous circuit 1
7 is a frequency setting means for outputting a control signal to the frequency variable circuit 6, and 8 is a frequency variable circuit for varying the pulse width to the transmitter 2 in synchronization with the output signal of the frequency variable circuit 6. A variable wave number circuit 9 is a wave number setting means for outputting a control signal to the variable wave number circuit 8.

Next, the operation of the above embodiment will be explained with reference to FIGS. 1 to 3. Based on the output signal of the synchronous circuit 1, the variable wave number circuit 8 outputs an operating time control signal CLT _o (CLT _o shown in FIG. 3) of the variable frequency circuit 6 in accordance with the set value set by the wave number setting means 9. do. The frequency variable circuit 6 is the output signal of the wave number variable circuit 8.
Frequency setting means 7 within the time controlled by CLT _o
A pulse (CLTW _no shown in FIG. 3) corresponding to the setting value set in is output to the transmitter 2. Transmitter 2
outputs a transmission signal corresponding to the output signal CLTW _no ) of the variable frequency circuit 6 to the probe 3. In this embodiment, the above operation is performed as CLTW _n as shown in FIG.
(m=1, 2, 3, . . .) in a certain time period {“n” in the wave _number (n= 1, 2, 3, . ” is the maximum (nt shown in Figure 2)} is fixed and the wave number “n” controlled by the output signal CLT _o of the variable wave number circuit 8 is increased sequentially, and the output signal of the variable frequency circuit 6 is Get CLTW _no . Further, when the wave number setting means 9 has finished setting the wave number "n" controlled by the output signal _CLTo of the wave number variable circuit 8, the wave number setting means 9 sets n=1. At the same time, the frequency setting means 7 sets the output signal CLTW _no of the frequency variable circuit 6 to m=2, and the frequency variable circuit 6 outputs CLT _w 21 shown in FIG.

By repeating the above operations, the frequency and wave number of the ultrasonic waves incident on the test material from the probe 3 are varied, and the ultrasound waves propagate through the test material. The propagated ultrasonic wave is again converted into an electric signal by the probe 3 and is displayed on the display 5 via the receiver 4. By monitoring the echo on the display 5, the frequency variable circuit 6 The optimum conditions for the output signal CLT _w of the test material (the value "n" set by the wave number setting means 9 and the value "m" set by the frequency setting means 7) are clarified, and the optimum conditions for the test material are determined. You can choose. Next, the operation of the variable wave number circuit 8 and the variable frequency circuit 6 will be explained with reference to the embodiment shown in FIG. Third
In Figure a, the variable wave number circuit 8 includes a mono multivibrator (hereinafter referred to as M/M) 10 and a resistor R _a1.
~R _ao (R _a1 <R _a2 <...<R _ao ), a selector A13 for switching the resistors R _a1 to R _ao , and a capacitor C _a . Also, the frequency variable circuit 6 is a resistor R _B1
~R _Bo (R _B1 < R _B2 <... < R _Bo ), selector B14 that switches resistance R _B1 ~ R _Bo , resistor R _c1 ~ R _co (R _c1 < R _c2
<...<R _co ), selector C15 that switches resistors R _c1 to R _co , capacitors C _B , C _c and M/MB, C1
It consists of 1 and 12.

M/MA 10 is selected by selector A 13 based on the control signal set by wave number setting means 9.
_{The third _}
An output signal CLT _o having a time width t _a shown in FIG. b is output. The M/MC 12 is synchronized with the output signal CLT _o of the M/MA 10, and is connected to a third circuit by predetermined resistors R _c1 to R _co selected by the selector C 15 based on the control signal set by the frequency setting means 7 and a capacitor C _c . Output signal with time width _tw shown in figure b
Output CLTW _no . M/MB11 is M/MC1
t shown in FIG. 3D is selected by the selector _B14 based on the control signal set by the frequency setting means 7 in synchronization with _one output signal _{CLTW no} of 2. An output signal CLD _w having a time width of _w is output to one input terminal of the M/MC 11 .

Since the variable wave number circuit 8 and the variable frequency circuit 6 are configured as described above, it is possible to output to the transmitter 2 a signal whose transmission frequency and number of transmission waves can be varied.

The transmitter 2 receives the output signal of the frequency variable circuit 6.
CLTW _no (CLTW1.1, CLTW1.2, shown in Figure 2)
...Generates a transmission signal based on CLTW _no ).
The probe 3 varies the transmission wave number n and the transmission frequency m based on the transmission signal from the transmitter 2 and injects the ultrasonic wave into the specimen, so the echo displayed on the display 5 is adjusted to the wave number setting means 9. By monitoring each set value set by the frequency setting means 7, it is possible to know and set the set values of the wave number setting means 9 and the frequency setting means 7 that have the best S/N for the material to be inspected. I can do it.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to set the optimum transmission frequency and transmission wave number for the material to be inspected without selecting the probe or the main body of the ultrasonic flaw detection apparatus. This enables flaw detection at the frequency and wave number with the best S/N for the material to be tested, as well as near the probe (near-field sound field).
It has the characteristics that it is possible to know the phase interference at , and it is also possible to avoid it by varying the frequency.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an ultrasonic flaw detection device according to the present invention, and FIG. 2 is an operation timing diagram of the present invention.
FIG. 3 is an explanatory diagram of a variable wave number circuit to a variable frequency circuit according to the present invention, and FIG. 4 is a block diagram of a conventional ultrasonic flaw detector. In the figure, 1 is a synchronizing section, 2 is a transmitting section, 3 is a probe, 4 is a receiving section, 5 is a display, 6 is a variable frequency circuit, 7 is a frequency setting means, 8 is a variable wave number circuit, 9
10 is a wave number setting means, 10 to 12 are mono multivibrators, and 13 to 15 are selectors. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1 a synchronization section that generates a predetermined repetition frequency;
a transmitting section that generates a transmission signal based on the output signal from the synchronizing section; a variable wave number circuit that varies the number of transmission waves of the transmitting section in synchronization with the output signal of the synchronizing section; A wave number setting means for setting a wave number, a frequency variable circuit for varying the transmission frequency of the transmitter based on an output signal of the variable wave number circuit, a frequency setting means for setting a frequency to the frequency variable circuit, A probe that converts the generated transmission signal into an ultrasonic signal and injects the ultrasonic wave into the test material and converts the reflected wave from the test material into an electrical signal, and a probe that increases the electrical signal from the probe. 1. An ultrasonic flaw detection device comprising: a wide receiver; and a display that displays a waveform of the receiver.