JPH0357956A - Ultrasonic flaw detection apparatus - Google Patents

Abstract

PURPOSE:To prevent the generation of the reading error due to parallax and to detect a flaw at a high speed with high efficiency by mounting a means generating a plurality of amplitude curves and an alarm means having a plurality of alarm levels and discriminating the magnitude of a flaw echo by a region to display the same by the alarm means. CONSTITUTION:The signal received by an ultrasonic probe 1 is amplified by a receiving and amplifying circuit 2 to be detected by a detection circuit 3 and further amplified by a vertical amplifying circuit 4 to be displayed on a CRT. This flaw detection waveform signal is also inputted to comparators 71 - 73. An amplitude curve signal is formed by a function generating circuit 6 and divided in voltage by resistors 61 - 63 to be inputted to the comparing input terminals of the comparators 71 - 73 and the outputs thereof are inputted to an encoder 8 to perform the lighting display of lamp display devices 91 - 93. When the amplitude curve (alarm level signal) from the circuit 6 is divided by the resistors 61 - 63 to be controlled so as to coincide with H, M, L lines of echo division lines, for example, when a flaw echo peak exceeds the L-line, output appears on the comparator 73 and the display device 93 lights. As mentioned above, the region to which a flaw echo peak belongs is displayed so as to be recognized at a glance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic flaw detection device, and more specifically, an ultrasonic flaw detection device having a function of automatically determining and displaying the size of a defect in a sample to be inspected. This relates to ultrasonic flaw detection equipment.

[Prior Art] For example, when performing ultrasonic flaw detection on a welded part of steel, a distance-amplitude characteristic curve showing the relationship between the position of the defect and the echo height as shown in Fig. 2 is used! II (hereinafter referred to as amplitude curve) is created and displayed by hand on the cathode ray tube surface of the ultrasonic flaw detection device. Furthermore, +
Auxiliary amplitude curves such as 6 dB, −6 dB, −12 dB, etc. are also created. Of this amplitude curve, the line corresponding to 40% or more of the vertical scale of the cathode ray tube is defined as the H line, and the lines below this are defined as the M line and the L line in sequence. These lines are called echo segmentation lines and are segmented as shown in Table 1. Furthermore, the size of the defect is classified into grades as shown in Table 2 based on defect indication length, plate thickness, etc.

Table 1 Area division of echo height These amplitude curves are examined on the specimen and drawn on the CRT surface before carrying out the flaw detection operation. Then, the echo height of the defect discovered during flaw detection falls into which range.
Determined by visual inspection by a flaw detector.

There is also a flaw detection device that has a function of automatically determining the echo height of such defects and issuing an alarm.

FIG. 3 is a block diagram showing an example of a conventional device of this type.
The signal received by the ultrasonic probe 1 is amplified to an appropriate level by a reception amplifier circuit 2, corrected to a constant amplitude by a DAC circuit IO, and then detected by a detection circuit 3. This detected flaw detection waveform signal is further amplified by the vertical amplifier circuit 4 and displayed as a flaw detection waveform on the CRT. On the other hand, the flaw detection waveform signal is also manually input to the alarm setting circuit {2. 11 is an alarm setting device.

In this device, the alarm level is always set at a constant level regardless of the position where the defective echo appears on the CRT. Therefore, in response to changes in the distance of this defect, the receiving circuit changes the amplification degree over time, and corrects it so that the echo height from a certain size defect remains constant regardless of the distance (commonly known as a DAC function). ).

Furthermore, as shown in FIG. 4, there is also an ultrasonic flaw detection device that changes one alarm level in accordance with the amplitude curve generated by the function generating circuit 6 to display only the presence or absence of a defect.

[Problems to be Solved by the Invention] The method of visually determining the defect echo height by having a flaw detector do the following: (1) In order to draw an amplitude curve (echo division line) on the CRT surface, the flaw detection waveform drawn on the inner surface of the CRT and the Since there is a distance between them, parallax occurs.

(2) The task of scanning the ultrasonic probe, stopping the waveform at the position where the height of the defective echo peaks, and reading the height of the defective echo requires skill and is subject to individual differences.

(3) Flaw detection work while watching a CRT is very tiring.

(4) Difficult to automate.

Furthermore, in the method of combining the DAC function and the alarm setting function, (1) it takes time to adjust the DAC circuit;

(2) There is a correction error in the DAC circuit, and it is difficult to keep the echo height constant.

There are problems such as.

Furthermore, in the method of changing one alarm level according to the amplitude curve, (1) Since the alarm level is one level, it is only possible to determine the presence or absence of a defective echo, but it is not possible to determine the size of the defective echo by region. .

There are problems such as.

[Means for Solving the Problems] An ultrasonic flaw detection device according to the present invention includes means for generating a plurality of amplitude curves and an alarm means having a plurality of alarm levels, and is capable of determining an area based on the size of a defect echo. The alarm is displayed by an alarm means.

[Operation] A plurality of amplitude curves generated by the means for generating amplitude curves are adjusted to match the H, M, and L lines of the echo dividing line, and are inputted to the alarm level input of the alarm means. The alarm means compares each alarm level with the flaw detection waveform, and displays the comparison results with a lamp or the like. At this time, the comparison is made with much higher precision than the precision read visually on the CRT screen, and is faster in terms of power. Also, if a lamp or the like is used as a display, it can be identified as ON/OFF.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention. A signal received by the ultrasonic probe 1 is amplified to an appropriate level by a reception amplifier circuit 2 and detected by a detection circuit 3. This detected flaw detection waveform signal is further amplified by the vertical amplifier circuit 4 and displayed as a flaw detection waveform on the CRT. on the other hand,
The flaw detection waveform signals are also input manually to comparators 71 to 73.

The amplitude curve signal is generated by the function generating circuit 6, further divided by the resistors 81-63, and input to the other comparison inputs of the comparators 7i-73. The outputs of the comparators 71 to 73 are input to the encoder 8, and the lamp indicators 91 to 93 are turned on and displayed. The amplitude curve signal (alarm level signal) from the function generating circuit 6, which is applied to the comparison power of the comparators 7l to 73, is divided by the resistors 61 to 63 to generate echo division lines H and M.
, L line, for example, when the defective echo height exceeds the L line, an output appears on the comparator 73, and the lamp indicator 93 lights up via the encoder 8. In this way, the area classification to which the defective echo height belongs is displayed so that it can be seen at a glance. It may also be indicated by sound, such as the pitch of the sound.

Although the above embodiment shows the case of an analog circuit, these functions can also be replaced with a digital circuit. Furthermore, it is also possible to achieve this on a program as microcomputer software.

[Effects of the Invention] As described above, the present invention includes a means for generating a plurality of amplitude curves and an alarm means having a plurality of alarm levels. Since the area divisions of the echo heights of the echoes are displayed, (1) reading errors due to parallax, which occur when reading defective echo heights from a CRT surface, do not occur.

(2) If the area classification is displayed by sound, the user can concentrate on scanning with the ultrasound probe.

(3) Since it is not necessary to perform flaw detection while constantly looking at the CRT, the fatigue of the flaw detection operator is reduced.

(4) Easy to automate.

(5) The amplitude curve can be monitored on a CRT and fine adjustments can be made, making adjustment work easier.

(6) If the alarm level is exceeded even momentarily, the alarm means is activated, so flaw detection can be performed faster and more efficiently.

Many other effects can be obtained.

Furthermore, if the present invention is utilized, a small and lightweight ultrasonic flaw detection device without a CRT can be realized using only a defect echo height area discrimination display lamp, and other derivative effects will also be produced.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing the relationship between the position of a defect and the height of an echo, and Fig. 3 is a diagram of a conventional technology consisting of a DAC circuit and an alarm setting device. Block Diagram FIG. 4 is a block diagram of another prior art. In the figure, 1 is an ultrasonic probe, 2 is a receiving amplifier circuit, and 3 is an ultrasonic probe.
is a detection circuit, 4 is a vertical amplifier circuit, 5 is a CRT, 6 is a function generation circuit that generates an amplitude curve, 61 to 63 are resistors, 7
1 to 73 are comparators, 8 is an encoder, and 9l to 93 are indicators.

Claims (1)

[Claims] An apparatus for ultrasonic flaw detection of steel billets, forgings, welded parts of steel materials, etc., comprising means for generating a plurality of amplitude curve signals and an alarm means having a plurality of alarm levels, An ultrasonic flaw detection apparatus characterized in that the size of the area is determined and displayed by the warning means.