JPH0843360A - Method and device for ultrasonic angle beam flaw detection - Google Patents

Abstract

PURPOSE:To provide an ultrasonic flaw detection method and device for it which can shorten the scanning distance of an array probe. CONSTITUTION:In a probe 1 a specimen to be inspected and array vibrators 2 are incorporated, wherein the vibrators 2 have the same inclining angle to the probe contacting surface 1a as the specimen, are laid in parallel so that the ultrasonic wave transmitted direction is at a right angle to the beam control direction, and are divided into several groups. Pulse voltage is impressed on these groups one after another so that ultrasonic waves are generated, and movement is made when all groups are finished, followed by another cycle repeatedly, and thereby flaw detection is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting defects in a welded portion using ultrasonic waves.

[0002]

2. Description of the Related Art An ultrasonic oblique angle flaw detection method is known as a method for flaw detection of welded steel plates or welded portions of steel pipes. This ultrasonic bevel flaw detection method applies a pulse voltage to a transducer inside a probe to generate an ultrasonic wave, makes the ultrasonic wave enter a subject at a constant angle, and causes the reflected wave to pass through the transducer. It is a method of finding the position, size, etc. of a defect by receiving the signal in the above and analyzing the signal.

This probe for ultrasonic oblique angle flaw detection usually incorporates a single oscillator for ultrasonic wave generation, and while driving the oscillator, it is two-dimensionally front and rear and left and right along the welded portion. Since the method of inspecting with a simple movement is adopted, labor and time are required for the inspection. Therefore, a method of scanning the probe two-dimensionally by a mechanical means has been proposed, but in the case of such a mechanical method, not only the contact with the subject is unstable but also There is a problem that a measurement error occurs depending on the scanning speed.

Further, there is known a system in which a large number of array transducers are incorporated in a probe to perform scanning while controlling driving by an electronic system (Japanese Patent Laid-Open No. 64-57165).

[0005]

However, in the case of the above-mentioned probe scanning method, it takes a long time for inspection, and in the case of the electronic scanning method, it is difficult to control and the driving electronic circuit becomes complicated. There are drawbacks. It is an object of the present invention to propose an ultrasonic flaw detection method and its apparatus that require a short inspection time, are easy to control, and have simple drive electronic circuits.

[0006]

The structure of the ultrasonic bevel flaw detection method and its apparatus according to the present invention is as follows.

1. A number of array transducers with the same bevel angle are installed in parallel so that the propagation direction of ultrasonic waves and the beam control direction are at right angles, and a pulse voltage is applied to each group of array transducers. Ultrasonic bevel flaw detection method performed while generating ultrasonic waves for each.

2. An array probe in which a large number of array transducers having a certain oblique angle with respect to a contact surface with respect to a subject are installed in parallel so that the propagation direction of ultrasonic waves and the beam control direction are perpendicular to each other, and the array probe. An ultrasonic oblique-angle flaw detector comprising: an array flaw detector including a control circuit that applies a pulse voltage to each group of transducers to generate ultrasonic waves.

[0009]

The control circuit applies a pulse voltage to the array transducer for each group. As a result, the array transducer to which the voltage has been applied simultaneously generates ultrasonic waves, which are incident on the inside of the subject and are reflected by the defects and the bottom surface. This reflected wave enters the driven array transducer again. The incident reflected waves are converted into electric signals in the array transducer and enter into the CPU, where they are analyzed and displayed as a reflected waveform on the display means, for example.

The array transducers are driven by applying a pulse voltage in order for each group, and when all the groups have been driven, the array probe is moved in the two-dimensional direction to perform grouping in the same manner as above. Every time the array transducer is driven, the inspection target portion of the subject is thoroughly scanned.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, in which an array probe 1 has the same inclination with respect to a contact surface 1a with an object to be inspected. The array transducers 2 having angles and arranged in parallel so that the propagation direction of ultrasonic waves and the beam control direction are at right angles are incorporated.

Reference numeral 3 denotes a control circuit, which is composed of a pulse generator 4, an electronic switch 5, an amplifier 6, a gate circuit 7, an A / D conversion circuit 8, a CPU 9 and a display unit 10. The child 2 is divided into groups, and each group is controlled as follows.

The electronic switch 5 applies the pulse voltage generated by the pulse generator 4 to the array transducers 2 for each group (for example, 10 array transducers 2). The array transducers 2 to which the pulse voltage is applied at the same time simultaneously generate ultrasonic waves, and the ultrasonic waves are generated by the contact surface 1 of the array probe 1.
The ultrasonic wave that has entered the object 11 from a and is reflected by a flaw, a bottom surface, or the like is received again by the array transducer 2, converted into an electric signal, and converted by the gate circuit 7 to A / D-convert a desired range. It passes, is processed by the CPU 9, and is displayed as a waveform on the display 10. Next, the same operation is sequentially performed for each group of array transducers 2. The grouping in which the pulse voltage is applied and driven at the same time is created by shifting the array transducers 2 one by one.

In FIG. 2, A is a pulse generated by the pulse generator 4, B is a control signal of the electronic switch 5 which applies this pulse to the array transducer 2 for each group, and C is a reflected waveform (signal). The signal is a signal that has passed through the gate circuit 7 that extracts only the required waveform, and this signal enters the CPU 9 from the A / D conversion circuit 8, and the analyzed waveform is the display 1
Displayed at 0.

When the array probe 1 has finished driving the entire group, it is retracted by, for example, 1 mm, and the above-described operation (electronic left-right scanning) is performed. It is further retracted by 1 mm and the above operation is repeated, and the inspection is performed along the welded portion 12 of the subject 11 by two-dimensional movement.

[0016]

As described above, according to the present invention, the scanning distance of the probe can be greatly shortened by performing scanning while driving the array transducers in the array probe for each group.

For example, in the case where the number of array transducers is 21 and the front-back scanning is 50 mm and the left-right scanning is 55 mm, when a group of 10 transducers is used, a probe having one transducer normally used is used. 50 mm x 55 for tentacles
It is necessary to scan 2750 mm times, but according to the present invention, 50 mm × 5 times = 250 mm, and the scanning distance is 1/10 or less. The scanning distance can be further shortened by increasing the number of array transducers 2.

Therefore, the inspection time can be greatly shortened and the array transducers are driven for each group, so that the drive circuit can have a simple structure.

[Brief description of drawings]

FIG. 1 is an explanatory view of an ultrasonic bevel flaw detection method and an apparatus therefor according to the present invention.

FIG. 2 is an explanatory diagram of a control example for an array transducer.

[Explanation of symbols]

 1 Array Probe 2 Array Transducer 3 Control Circuit 4 Pulse Generator 5 Electronic Switch 6 Amplifier 7 Gate Circuit 8 A / D Conversion Circuit 9 CPU 10 Display

Claims (2)

[Claims] 1. A plurality of array transducers having the same oblique angle are laterally arranged in parallel, and a pulse voltage is applied to each group of the array transducers to generate an ultrasonic wave for each group. Ultrasonic bevel flaw detection method. 2. An array probe in which a large number of array transducers having a certain oblique angle with respect to a contact surface with respect to a subject are installed in parallel so that a propagation direction of an ultrasonic wave and a beam control direction are perpendicular to each other. And an array flaw detector including a control circuit that applies a pulse voltage to the array transducer of the array probe for each group to generate an ultrasonic wave, and an ultrasonic bevel flaw detector.