JPS62144066A - Ultrasonic flaw detector - Google Patents

Abstract

PURPOSE:To enable highly accurate flaw detection with uniform sensitivity over the entire flaw detecting surface, by making a probe movable vertical to an object to be inspected follow up changes in the water distance. CONSTITUTION:A water distance measuring circuit 11 measures a distance to an object 2 to be inspected by an ultrasonic video signal (c) of a flaw detector (b) and set reference data to keep water distance constant on a compare circuit 12 beforehand. The circuit 12 compares measurement data (j) with the water distance reference data and when they differ, it outputs a differential signal (k) to a A axis control circuit 10 which outputs a Z axis control signal to move a Z axis scanner 6 in the direction of nullifying the difference. Thus, as the water distance between the surfaces of the object 2 being inspected is kept constant regardless of the state of the flaw detection surface, the probe 1 accomplish a high accurate flaw detection with uniform sensitivity over the entire flaw detecting surface.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an ultrasonic flaw detection device having a mechanism for scanning a probe in ultrasonic flaw detection using the water immersion method. The present invention relates to an ultrasonic flaw detection device suitable for water immersion flaw detection.

[Background of the invention]

Conventionally, regarding ultrasonic flaw detection using the water immersion method, there is a water immersion method in the document titled 1 Ultrasonic deep flaw method (revised new edition) H published by the Japan Society for the Promotion of Science and the Nikkan Kogyo Shimbun (July 30, 1972). As discussed in the immersion method page, it was necessary to consider the installation of the probe and the object to be inspected in order to keep the water distance between the object to be inspected, the probe, and the probe constant, and maintain flaw detection sensitivity. . but,
With conventional devices, once the water distance is set, it is fixed and cannot be tracked, so no consideration was given to keeping the water distance constant.

[Purpose of the invention]

The object of the present invention is to maintain a constant water distance between the probe and the surface of the object to be inspected, regardless of the depth or depth of the inspection surface, and to perform accurate flaw detection at a uniform angle of 1° over the entire flaw detection surface. The purpose of the present invention is to provide a sonic a flaw detection device.

[Essentials of invention]

The water distance between the probe and the surface of the object to be inspected changes depending on the surface shape of the object to be inspected. Even in such a case, the probe follows the water and always maintains a constant distance from the water.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 7 shows a block diagram of a conventional ultrasonic flaw detection system. The flaw detector synchronization signal d output from the processing device 7 synchronizes the flaw detector and drives the probe 1. Probe 1 is
Transmits ultrasonic waves and receives reflected waves from the object to be inspected. The flaw detector S inputs the probe transmitting/receiving signal C, and outputs an ultrasonic video signal C after amplifying, detecting, and detecting the signal. The scanner control device 5 sets a stroke to scan the flaw detection range of the inspected object 2, and controls the scanner 4 in the X direction and Y direction (outputs U e-f. Control signals e and f The scanner 4 scans the probe 1 in the X direction and the Y direction.The scanner control device 5 outputs a position signal gh in accordance with the scanning of the probe 1.The processing device 7 scans the probe 1 in the X direction and the Y direction. The signal gh and the ultrasonic video signal C are input to perform various processing.The recording device 8 inputs the processed signal i and records/records the processing results.
Show light.

FIG. 1 shows a block diagram of an ultrasonic flaw detection apparatus according to the present invention. The block shown in FIG. 1 is the block shown in FIG. 7 with a water distance measuring circuit 11 and a comparison circuit 12 added thereto. Using the ultrasonic video signal C, the water distance measuring circuit 11 measures the distance to the object to be inspected.

Standard data for keeping the water distance constant is set in the tightening comparison circuit 12. The comparison circuit 12 compares the water distance reference data and the measured data j, and if a difference is found, outputs a difference signal k to the two-axis control device 10. 2-axis control device 1
At o, if the difference between the water distance reference data and the measured data is (+), the two-axis scanner 9 moves in the direction of (0)K.
Outputs axis control signal l. Also, if the difference is (-),
A two-axis control signal l is output so that the two-axis scanner 9 moves in the direction of (0). In this way, the probe 1 can maintain the set water distance.

FIG. 2 shows an example of the operation of FIG. A, B, ClD
This shows the relationship between water distances at points, and since the water distances differ at each point, the flaw detection sensitivity also differs.

FIG. 3 shows an example of the operation of FIG. A, B, C.

This shows the relationship between the water distance at point D. Since the two-axis scanner 9 follows each point, the water distance is constant and the flaw detection sensitivity is also constant.

FIG. 4 is a timing chart and a block diagram of the water distance measuring circuit 11, in which the interval between the transmitted wave (T) of the ultrasonic video signal C from the detector 6 and the surface wave (81) is counted using a reference clock. For example, When the reference clock is lOMHz,
Since the sound speed of water is 1480 m/s, one clock count is equivalent to 0.074 mm. Water distance 4Qmm
In this case, the count is 541.

FIG. 5 is an explanatory diagram of the two-axis drive section. The Z-axis drive unit is
It is possible to move in the X-axis and Y-axis directions, and the vertical movement of Z41
Xhv'i, connected to the gear by motor 13, motor 1
3. Move the Z-axis up and down using the forward and reverse rotations.

FIG. 6 is an explanatory diagram of the water distance and the Z-axis control signal. Set the water distance at point A and move to point B. At point B, the water distance is measured and since it is different from the set water distance, a difference signal is output to the Z-axis control circuit. The Z-axis control circuit outputs a Z-axis control signal so that the motor rotates in the direction in which the Z-axis rises.
Rotate the motor to raise the Z-axis and follow changes in water distance. Also, at point 0, contrary to point B, ZOI]
rotates the motor in the downward direction to follow Z and ll1iI.

According to this embodiment, even if the water distance changes with respect to the established value, the Z-axis follows, so it is possible to maintain a constant water distance and flaw detection sensitivity.

〔Effect of the invention〕

According to the present invention, in ultrasonic flaw detection using the water immersion method, since the water distance can always be kept at a constant value, the flaw detection sensitivity can be averaged, so accurate flaw detection can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
A conventional explanatory diagram, FIG. 3 is an explanatory diagram of the present invention, and FIG. 4 is an explanatory diagram of the present invention.
Horizontal distance measurement timing chart and block diagram, Part 5
This figure is a mechanical diagram of the Z-axis, FIG. 6 is an explanatory diagram of a Z-axis control signal, and FIG. 7 is a block diagram of a conventional example. 9...Z-axis scanner, 10...Z-axis control signal, 11
...Water distance measurement circuit, 12...Comparison circuit, 13...
·motor.

Claims (1)

[Claims] 1. A water immersion probe that uses liquid as a couplant to detect defects in an object to be inspected using ultrasonic waves in a non-contact manner, and this probe is held and scans the flaw detection surface of the object to be inspected. a scanner having a scanning mechanism for controlling the scanning mechanism of the scanner and counting the position of the probe; and a scanner control device for controlling the scanning mechanism of the scanner and counting the position of the probe; A flaw detector that amplifies and detects a sound wave signal and displays it on the A scope; and a processing device that takes in the position signal of the probe from the scanner control device and the defect detection signal from the flaw detector and performs various processing. and a data output device for displaying and recording the processing results from the processing device. The part of the scanner that holds the probe is moved perpendicularly to the object to be inspected by a mechanism that moves in a direction perpendicular to the object to be inspected and a control signal from the water distance measuring circuit. An ultrasonic flaw detection device characterized by being equipped with a vertical direction control circuit that controls and maintains a constant water distance.