JPH0437948B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a split vertical probe verification method for automatic ultrasonic flaw detection equipment for thick plates.

``Prior Art'' Automatic ultrasonic flaw detection equipment equipped with dozens or more vertical vertical probes is used to detect internal defects in thick steel plates. The configuration of this split vertical probe is as shown in FIG.

In the figure, an ultrasonic probe 1 containing a built-in transducer 2 that is responsible for transmitting and receiving ultrasonic waves is fixed to a probe holder 4, and a probe shoe 5 scans the surface of a steel plate 7. At this time, a certain amount of water film gap 6 is formed between the probe and the surface of the steel plate.

Automatic ultrasonic flaw detection equipment for thick plates generally includes a group of several dozen or more probes arranged in a dispersed manner over the entire width of the thick plate.

Note that 3 in the figure indicates the acoustic division plane.

As an ultrasonic flaw detection method using this probe, a sensitivity setting method based on the bottom echo of a test plate or a specific test piece is generally adopted.

That is, the size of an internal defect in a steel plate is evaluated by the ratio of the echo output reflected from the defect to the bottom echo output as a reference.

However, due to improper installation of the probe or uneven wear of the probe shoe, the probe may be attached at an angle with respect to the surface of the steel plate.

In other words, Fig. 3 shows the probe installed at an angle, and 8 in the figure is the inclination in the longitudinal direction of the transducer.
9 indicates the inclination of the vibrator in the width direction. on the other hand,
In automatic flaw detection, as described above, in order to control the flaw detection conditions of each probe to be constant, as shown in FIG. It is common to evaluate the size of a defect based on the output of a defect echo 14 (referred to as F) detected during flaw detection based on the echo height.

Therefore, as shown in FIG. 6, the characteristic of the probe mounted at an angle as shown in FIG. 3 is that F/BG becomes significantly large, resulting in overestimation of defects.

Such errors also occur due to deterioration of the probe itself (for example, due to damage to the diaphragm of the probe).

Therefore, if flaw detection is carried out under such conditions, it will not be possible to accurately evaluate defects, resulting in a lack of reliability.

Therefore, in order to control the number of probes and the accuracy of probe installation, a test piece 10 with an artificial flat-bottom drill hole 10a is used as shown in Fig. 4a, and each probe is The method used is to check each item one by one.

``Problems to be Solved by the Invention'' However, the method described above requires time and effort to align the scanning of the probe with the artificial flat-bottomed drill hole 10a, and is extremely inefficient. Yes, it required a lot of effort and time.

"Means for Solving the Problems" The present invention was made in view of the above circumstances, and its gist is that a plurality of long slits are provided in parallel at the bottom of the test piece, and By arranging a plurality of split vertical probes in the direction, and arranging the acoustic splitting surface of the probe in the direction perpendicular to the slit, the test piece and the probe are moved relative to each other for verification. It is possible to easily test a large number of probes at the same time by making the concave portion orthogonal to the acoustic splitting plane into a long slit.

"Effect", "Example" This will be explained in detail below based on the drawings.

The configuration of the present invention is shown in FIG. In other words, in order to detect internal defects in thick steel plates, automatic ultrasonic flaw detection equipment uses dozens or more vertical vertical probes, and the deterioration of each probe and the accuracy of probe installation are controlled. For the purpose of
As shown in FIG.
and the acoustic dividing surface 3 of the probe 1 and the test piece 11.
While moving the probe group or the test piece group orthogonally to the slit-shaped artificial defect 11a, the ultrasonic echo output reflected from the bottom of the test piece, the echo output from the defect in the test piece, and the output above a certain level are detected. This allows you to easily measure the distance and the F/BG and effective beam width of each probe.
This scanning is performed by driving either the probe group or the test piece group using hydraulic pressure, pneumatic pressure, or an electric motor.

During this scanning, the bottom echo output BG and defect echo output F from the ultrasonic flaw detector 17 are recorded by the recording device 18 (pen recorder) and the digital recorder 19.
This allows F/BG to be recorded using computers and printers. Furthermore, if there is a scanning distance signal at this time, it is also possible to measure the ultrasonic beam width shown at 16 in FIG. 5 at the same time.

According to the configuration described above, due to the characteristics of the split vertical probe, the split surface of the probe and the flat-bottomed slit-like defect 11a are necessarily orthogonal regardless of the installation position of the probe. This results in the same result as when drilling a hole with the corresponding slit width diameter.

In other words, the drill hole must be inspected. Moreover, multiple items can be used at the same time.

The ultrasonic characteristics in the test are shown in FIGS. 7a and 7b for normal and abnormal conditions.

In the figure, 15a and 15b are the reflected echo outputs from the bottom surface during normal and abnormal times, 14a and 14b are during normal times,
The reflected echo outputs from the defects at abnormal times are shown respectively.

Similar results can be obtained not only when the probe is tilted but also when the transducer is missing.

Therefore, 16a>16b (16a and 16b are measurement beam widths in normal and abnormal conditions), 14a/15a
Abnormality is determined with a measurement result of <14b/15b.

"Effects of the Invention" As described above, according to the present invention, the number of
It is possible to automatically check the health of as many as 10 probes, making it easy to maintain and manage flaw detection accuracy.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the configuration of the present invention;
Figures 2a and b are front and side views of the split vertical probe;
Figures 3a and b show the positive position of the probe mounted at an angle.
A diagram showing a side aspect, FIGS. 4a and 4b are a conventional test piece, a plan view and a front view of a test piece according to the present invention, and FIG. 5 is an explanatory diagram of a reflected echo output aspect during probe scanning.
FIG. 6 is a diagram showing the relationship between the probe inclination and the reflected echo output, and FIGS. 7a and 7b are diagrams showing changes in the reflected echo output during probe scanning. Explanation of symbols, 1... Split vertical probe, 2...
Ultrasonic transducer, 3... Acoustic dividing surface, 4... Probe holder, 5... Probe shoe, 6... Water film gap, 7... Test plate or test piece, 8... Vibrator Inclination in the length direction, 9...Inclination in the transducer width direction, 10
... Artificial defect flat-bottom drill hole, 11 ... Artificial defect slit-like defect, 14 ... Reflected echo from defect,
15... Echo reflected from the bottom, 16... Beam width, 17... Ultrasonic flaw detector, 18... Pen recorder, 19... Digital recorder.

Claims (1)

[Claims] 1. A means for testing a large number of ultrasonic probes, in which a plurality of long slits are provided in parallel at the bottom of a test piece, a plurality of split vertical probes are arranged in a direction perpendicular to the slits, and A split-type vertical detection of automatic ultrasonic flaw detection equipment for thick plates, characterized in that the acoustic splitting surface of the probe is also arranged in the direction perpendicular to the slit, and the test piece and the probe are moved relative to each other for verification. Tentacle test method.