JP4884930B2 - Ultrasonic flaw detection apparatus and method - Google Patents

Description

  The present invention relates to an ultrasonic flaw detection method and apparatus, and more particularly to an ultrasonic flaw detection apparatus and method for detecting a defect present in a subject having a complicated surface shape.

  Various defects may occur in the welds of steel structures. That is, when mechanical stress or thermal stress is applied to such a steel structure, the welded portion is distorted and fatigue cracks are formed. The crack may spread.

  Ultrasonic testing (UT) has been known as a nondestructive inspection test method for defects such as scratches and cracks on the inside of an object or on the inner surface of an inaccessible object. The test results can be displayed immediately, and when a defect is detected, it can be dealt with immediately. It is widely used in various nondestructive inspection methods.

  In this ultrasonic flaw detection method, an ultrasonic wave is generated by applying a pulse voltage to a transducer in a probe (probe) arranged on the surface of an object, and is directed from the object surface to the inside of the subject or the inside of the subject. The state of the defect such as the size, type, and position is determined by receiving and analyzing the reflected ultrasonic wave with a probe.

However, in this ultrasonic flaw detection method, if there is air between the probe (probe) and the subject, the ultrasound does not reach the subject, but the surface of these welds is usually uneven, Specifically, the flaw detection is performed by filling the space between the probe and the subject surface by a water immersion method using water or oil as a coplant.
However, for example, when a pipe is penetrated through a steel plate and welded, there is a buildup around it, the inspection site is not flat, and the shape changes complicatedly, for example, it is difficult to inspect even with the water immersion method There was a problem. Particularly, as shown in FIG. 13, when the pipe 81 is penetrated at a certain angle in the steel plate 80, the build-up shape by welding around the pipe is, for example, 82 depending on the position where the pipe contacts the steel plate. , 83, and therefore, it becomes more difficult, and conventionally, such an inspection by an ultrasonic flaw detection method has not been performed.

That is, in such an ultrasonic flaw detection method, a time difference is given to ultrasonic waves generated by transducers arranged in a line or transducers arranged in a matrix, and the reflected waves are observed by focusing on a specific position. However, if the surface shape is not constant, for example, as indicated by 71 in FIG. 14A, the refraction direction of the ultrasonic wave that has entered the subject will be different from the intended direction, and the beam may spread. The problem arises that it does not converge where desired.
Therefore, as shown in FIG. 14B, surface irregularities are measured by initial transmission / reception from probes (probes) 72 arranged in a row, and as shown in FIG. There is an adaptive UT method (adaptive ultrasonic flaw detection method) that feeds back the results and corrects the influence of the unevenness in consideration of the delay time and converges the beam to a single point P.

  Further, Patent Document 1 is known as a technique for measuring a surface shape of an inspection object in advance and thereby performing an ultrasonic flaw by converging the focal point, and the ultrasonic flaw detection apparatus disclosed in Patent Document 1 is described below. In conventional ultrasonic flaw detection, ultrasonic waves are transmitted in the vertical direction on the assumption that there is a reflector on the front, and imaging with a specific depth of focus is performed. Since the focus has varied and high-accuracy imaging has been impossible, an image of the surface shape and internal state of the object to be inspected is synthesized based on the round-trip ultrasonic propagation time data using a matrix probe. It was designed to detect flaws.

JP 2005-241611 A

  However, the ultrasonic flaw detection apparatus disclosed in Patent Document 1 preliminarily synthesizes an image of the surface shape of the inspection target, thereby performing ultrasonic flaw detection while preventing variation in focus. It is intended for welds with beads on the surface, and it is accurate for flaw detection in parts where the built-up shape is more complicated, such as the welds of pipes that penetrate through steel plates at an angle as described above There is no suggestion of techniques for measuring surface shapes well.

Further, as described above, in the adaptive UT method, the surface shape result is fed back, the influence of the unevenness is corrected in consideration of the delay time, and the inspection is performed so that the beam converges to one point. Measurement accuracy is important for improving the accuracy of the adaptive UT method.
Furthermore, since the refraction angle between water and oil and the surface changes depending on the speed of sound in water or oil as well as the speed of sound in the inspection object as a coplant, there is a problem that the convergence position changes when the sound speed shifts. Therefore, accurate sound speed measurement is important for improving the accuracy of the adaptive UT method.

  The present invention has been made in view of the above points, and is an adaptive UT that performs flaw detection in a portion where the build-up shape is complicated, such as a welded portion of a pipe penetrated at a certain angle through a subject. It is an object of the present invention to provide an ultrasonic flaw detection apparatus and method capable of improving the flaw detection accuracy of a method and obtaining a reliable inspection result.

In order to solve the above problems, an ultrasonic flaw detection apparatus according to the present invention has a phased array probe in which a plurality of transducers that emit ultrasonic waves are arranged on a subject to face the subject, and based on the shape of the subject surface, The ultrasonic wave emission delay time of each transducer is calculated so that the ultrasonic wave emitted from each transducer is focused on a predetermined position inside the subject, and the ultrasonic wave is focused on the predetermined location inside the subject to detect flaws. an ultrasonic flaw detection apparatus which performs,
Transmission control means for supplying ultrasonic waves to the vibrator, reception control means for receiving ultrasonic waves reflected from the subject via the vibrator , and ultrasonic waves received from the reception control means for the transmission control is controlled by means and said reception control means with a plurality of calculating the surface shape data of a predetermined range of the subject, the surface shape calculating means for calculating the surface shape of the subject by synthesis of the surface shape data of the plurality of the equipped,
The surface shape calculation means controls the emission timing of the ultrasonic waves from the transmission control means to emit light at a plurality of angles to the subject, and a plurality of surface shapes obtained by signals emitted at the plurality of angles The surface shape of the subject is calculated by synthesizing the data, and the synthesis sets one of a plurality of surface shape data obtained at the emission of each angle as a reference surface shape, and the remaining surface shape data is When the reflection intensity is higher than the reference surface shape data, the surface shape is calculated by moving to the data having a high reflection intensity so as to form a smooth curve .

In the ultrasonic flaw detection method according to the present invention, a phased array probe in which a plurality of transducers that emit ultrasonic waves are arranged on a subject is opposed to the subject, and each of the transducers is based on the shape of the subject surface. The ultrasonic wave emission delay time of each transducer is calculated so that the ultrasonic wave emitted from the object is focused on a predetermined position inside the subject, and the ultrasonic wave is focused on the predetermined position inside the subject to perform flaw detection. a testing method,
By controlling the emission timing of the ultrasonic wave transmitted from each of the plurality of transducers to emit at a plurality of angles with respect to the subject, the light is emitted at the plurality of angles with respect to a predetermined range of the subject. A plurality of surface shape data are calculated from the obtained signals, and the surface shape of the subject is calculated by combining the plurality of surface shape data, and the combining is performed on a plurality of surfaces obtained at each angle of emission. Any one of the shape data is set as a reference surface shape, and when the remaining surface shape data has a higher reflection intensity than the reference surface shape data, the data having a higher reflection intensity is moved to form a smooth curve. Thus, the surface shape is calculated .

According to the ultrasonic flaw detection apparatus and method, for calculated by plurality of the surface shape data or we synthesis a predetermined range of the surface shape of the object, to improve the measurement accuracy of the surface shape of the object, As a result, the calculation accuracy of the ultrasonic wave emission delay time of each transducer is improved so as to focus on a predetermined position inside the subject, and the flaw detection accuracy is improved.

And, according to the engagement Ru invention, for testing a plurality of angles relative to the surface shape, that the surface to obtain a strong reflected signal hits from a direction close to the direction perpendicular to the inclined surface be inclined As a result, the measurement accuracy of the surface shape is improved.
Compared to the case where the surface shape is calculated by flaw detection perpendicular to the surface of the subject, the surface shape can be measured over a wide range because the light is emitted at a plurality of angles. A wider range of measurements for the child.

Further , according to the present invention, the synthesis is performed by synthesizing the reflection data obtained by extracting the maximum intensity at the emission of each angle to calculate the surface shape. Therefore, when the surface shape is estimated, the reflection intensity is high (surface The position where the angle and the flaw detection angle are close to a right angle) is given priority, and the accuracy of the surface shape is improved.

Further , according to the present invention, the synthesis sets any one of a plurality of surface shape data obtained at the emission of each angle as a reference surface shape, and the remaining surface shape data is higher than the data of the reference surface shape In the case of the reflection intensity, the surface shape is calculated by moving to the data with a high reflection intensity so as to form a smooth curve, so that an extremely strong reflection portion due to noise is not simply synthesized. By correcting the change to obtain a smooth shape, accurate and highly accurate surface shape data can be obtained.

In the present invention, preferably , the surface shape calculation means controls and processes the emission signal from the transmission control means and the reception signal from the reception control means by an aperture synthesis processing method, and uses a plurality of surface shape data as a subject. The surface shape is calculated.
Aperture synthesis processing method is to transmit an ultrasonic wave by one transducer among multiple transducers, receive it by all other transducers and combine them in consideration of the phase, and then transmit all of them. This is a technique for obtaining high measurement accuracy by performing the synthesis at the position of the vibrator.
Accordingly, in such an invention, by using such an aperture synthesis processing method, the transmission timing and the reception timing of a plurality of transducers are controlled by the transmission control means and the reception control means, respectively, and a highly accurate surface shape is obtained. Data can be obtained.

In the present invention, it is preferable that the surface shape calculating means arbitrarily sets the depth of the focused position of the outgoing beam for flaw detection, and changes the depth of the new focus position to the surface shape obtained as a result of the flaw detection. The surface shape is measured again, the surface shape data is compared again with the previously calculated surface shape data, and the depth of the focusing position is changed repeatedly until the surface shape does not change. The configuration is such that the shape when it disappears is calculated as the surface shape of the subject.
According to the invention, the surface shape can be easily calculated by repeating the flaw detection by installing at an arbitrary position without calculating the distance between the subject and the probe or specifying the installation position. The shape measurement accuracy is improved.

According to the present invention, in the apparatus in which the subject is a welded part having a build-up shape, transmission control means for supplying ultrasonic waves to the vibrator, and ultrasonic waves reflected from the subject are passed through the vibrator. Receiving control means for receiving the sound, sound speed correcting means for correcting the ultrasonic sound velocity in the object based on the temperature of the object at the welding site, and the transmission control of the ultrasonic wave corrected by the sound speed correcting means. is controlled by means and said reception control means with a plurality of calculating the surface shape data of a predetermined range of the subject, the surface shape calculating means for calculating the surface shape of the subject by synthesis of the surface shape data of the plurality of the equipped,
The surface shape calculation means controls the emission timing of the ultrasonic waves from the transmission control means to emit light at a plurality of angles to the subject, and a plurality of surface shapes obtained by signals emitted at the plurality of angles The surface shape of the subject is calculated by synthesizing the data, and the synthesis sets one of a plurality of surface shape data obtained at the emission of each angle as a reference surface shape, and the remaining surface shape data is invention wherein when the high reflection strength than the data in the reference surface shape, characterized in that the surface shape by moving to a smooth curve data with a high the reflection intensity is calculated (claim 2 wherein )

According to such an invention, in order to correct the sound velocity in the subject based on the temperature of the subject, the refractive index can be calculated using a precise sound velocity, and as a result, focused on a predetermined position inside the subject . Calculation accuracy of the ultrasonic wave emission delay time of each transducer is improved, and flaw detection accuracy is improved.

Further, the invention according to claim 5 is the invention of the ultrasonic flaw detection methods described above, transmits received from each of the plurality of transducers, the ultrasonic wave sound velocity corrected based on the temperature of the object of the welded section The plurality of surface shape data is calculated from signals emitted at a plurality of angles with respect to a predetermined range of the subject, and the plurality of surface shape data are calculated. The surface shape of the subject is calculated by synthesizing the surface shape data, and the synthesis sets one of the plurality of surface shape data obtained in the emission of each angle as the reference surface shape, and the remaining When the surface shape data has a reflection intensity higher than that of the reference surface shape data, the surface shape is calculated by moving to the data having a high reflection intensity so as to form a smooth curve. A.

According to the invention, since flaw detection is performed from a plurality of angles with respect to the surface shape, a strong reflected signal can be obtained by hitting from a direction close to a right angle to the inclined surface even if the surface is inclined. Therefore, the measurement accuracy of the surface shape is improved.
Compared to the case where the surface shape is calculated by flaw detection perpendicular to the surface of the subject, the surface shape can be measured over a wide range because the light is emitted at a plurality of angles. A wider range of measurements for the child.

  According to the invention, the surface shape can be easily calculated by repeating the flaw detection by installing at an arbitrary position without calculating the distance between the subject and the probe or specifying the installation position. The shape measurement accuracy is improved.

According to the second aspect of the present invention, since the sound velocity in the subject is corrected based on the temperature of the subject, the refractive index can be calculated using the accurate sound velocity, and as a result, the refractive index can be calculated at a predetermined position inside the subject. The calculation accuracy of the ultrasonic wave emission delay time of each transducer is improved so as to converge, and the flaw detection accuracy is improved.

  As described above, according to the ultrasonic flaw detection apparatus and method according to the present invention, flaw detection is performed on a portion where the build-up shape is complicated, such as a welded portion of a pipe that penetrates the subject at a certain angle. It is possible to improve the flaw detection accuracy of the adaptive UT method and obtain a reliable inspection result.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

FIG. 1 is a schematic explanatory view showing the installation state of the probe of the present invention, (A) shows a state in which a pipe penetrates perpendicularly to a steel sheet, and (B) shows a state in which the pipe penetrates obliquely through the steel sheet. A cross-sectional view is shown. FIG. 2 is a block diagram of the control device in the first embodiment, FIG. 3 is an explanatory diagram showing an ultrasonic beam state of the first embodiment, and FIG. 4 is a flowchart showing a synthesis method of the first embodiment. FIG. 5 is an explanatory diagram showing the ultrasonic beam state of the second embodiment, FIG. 6 is a flowchart showing the synthesis method of the second embodiment, and FIG. 7 shows the ultrasonic beam state of the third embodiment. FIG. 8 is a flowchart showing the calculation of the surface shape of the third embodiment, FIG. 9 is an explanatory diagram showing the ultrasonic beam state of the fourth embodiment, and FIG. 10 is the calculation of the surface shape of the fourth embodiment. FIG. 11 is an overall control block diagram showing the fifth embodiment, and FIG. 12 is an explanatory diagram showing sound speed measuring means in the fifth embodiment.
(First embodiment)

  As shown in FIG. 1 (A), the ultrasonic flaw detection apparatus and method according to the first embodiment of the present invention penetrate a pipe 5 through a steel plate 3, weld the penetration position, and connect the welded portion 7 to a subject. As flaw detection. In particular, as shown in FIG. 1B, when the pipe 5 is inclined and penetrates the steel plate 3, the welded portion 7 has a complicated weld shape. The flaw detection is performed by an array-type probe 11 in which a plurality of transducers 9 that emit ultrasonic waves to the subject 7 are arranged in a line.

The probe 11 is attached to the welded part 7 at a fixed distance, and water as a coplant is interposed between the probe 11 and the welded part 7, and the adaptive UT method by the water immersion method. Detect flaws by (adaptive ultrasonic flaw detection method).
That is, the probe 11 in which a plurality of transducers 9 that emit ultrasonic waves are arranged on the subject 7 is opposed to the subject 7 through water of the coplanar, and each of the above-mentioned each is determined based on the surface shape of the subject 7. The ultrasonic wave emission delay time of each vibrator 9 is calculated so that the ultrasonic wave emitted from the vibrator 9 is focused at a predetermined position inside the subject, and the ultrasonic wave emitted by the calculated emission delay time is used. Perform flaw detection.

  The calculation of the surface shape information will be described in detail later, but in general, the distance from the probe 1 to the surface of the subject 7 is determined by the ultrasonic waves emitted from the probe 1 and reflected from the surface of the subject 7. Calculate and measure the surface shape. In calculating the delay time for each transducer 9 so that the ultrasonic beam is focused at a predetermined position inside the subject 7, it is important to accurately measure the surface shape information.

The control device 10 of the ultrasonic flaw detector will be described with reference to the block diagram shown in FIG.
The control device 10 includes a transmission control unit 15 that supplies ultrasonic waves to the transducer 9 of the probe 11, a reception control unit 17 that receives ultrasonic waves reflected from the subject 7 via the transducer 9, and transmission control. Shape data calculating means 19 for controlling the emission timing from each transducer 9 by means 15 and controlling the reception timing by reception control means 17 to calculate a plurality of surface shape data in a predetermined range of the subject 7; And a shape calculation unit 21 for calculating the surface shape of the subject 7 by comparing or synthesizing the surface shape data. The shape data calculating unit 19 and the shape calculating unit 21 constitute a surface shape calculating unit 22.
Further, it has a delay calculation means 20 for calculating the delay time of the ultrasonic wave emission of each vibrator 9 so that the ultrasonic wave emitted from each vibrator 9 is focused at a predetermined position inside the subject.

  Further, the control device 10 includes a shape memory 23 that stores the surface shape data of the subject 7 calculated by the shape calculation unit 21, a waveform memory 25 that stores a waveform of the reception signal received via the vibrator 9, and a waveform memory A data display calculation means 31 for displaying the flaw detection result inside the subject 7 on the monitor 27 and the data recording device 29 from the waveform stored in 25 is provided.

  In the first embodiment, the probe 11 composed of a plurality of transducers 9 is a phased array type probe, and the transmission delay time is set for the ultrasonic beam transmitted from each transducer 9. Thus, the beam angle emitted from the probe 11 can be set to an arbitrary angle other than vertical.

  The surface shape calculation means 22 controls the operation of the transmission control means 15 and the reception control means 17, thereby measuring the surface at the flaw detection angle X1 (for example, 10 degree flaw detection) shown in FIG. 3A, and shown in FIG. Ultrasonic beams are emitted at a plurality of angles so as to perform vertical surface measurement and surface measurement at a flaw detection angle X2 (for example, −10 degree flaw detection) shown in FIG. The reflection data is received by the reception control means 17 and stored in the waveform memory 25.

  From the reflection data stored in the waveform memory 25, a plurality of surface shape data of a predetermined range of the subject 7 is calculated by the shape data calculation means 19 according to the emission angle. Then, the surface shape data is synthesized by the shape calculation unit 21. By synthesizing, the shape in the range shown in FIG. 3D is measured. Further, the surface shape data at the respective angles are combined, and as a result, the combined surface shape data as shown in FIG. 3E is calculated.

  FIG. 4 shows a composition control flow chart in the shape calculation unit 21. As shown in FIG. 4, first, in step S1, the maximum intensity of the beam is extracted from the flaw detection result at each angle. That is, it can be used for grasping a position inclined in a direction close to a right angle with respect to the emission angle, and can be used as a reference when designating the overlapping range. In other words, it is possible to measure the surface shape with higher accuracy by overlapping ranges in which the maximum intensities of the flaw detection results are included.

In step S3, a range to be overlapped is designated. In step S5, the overlapping position is designated within the overlapping range. In step S7, the number of reflection data existing at the designated position is determined.
If the number is 0 (zero), the process proceeds to step S9, and the value of the position is none. If the number is 1, the process proceeds to step S11. The value of the position uses the reflection data of the beam. Advances to step S13 and adopts the value of the reflection data with the maximum intensity between the flaw detection results at each angle. Then, it is determined whether or not all the overlapping positions in the range designated in the next step S15 have been viewed. If not, the process returns to step S5 to specify the remaining positions and repeat steps S7 to S15. It ends when it sees.

  As described above, according to the first embodiment, since the surface shape of the predetermined range of the subject is calculated by combining a plurality of surface shape data, the measurement accuracy of the surface shape of the subject is improved, and as a result As described above, the calculation accuracy of the ultrasonic wave emission delay time of each transducer is improved so as to be focused at a predetermined position inside the subject, and the flaw detection accuracy is improved.

In other words, since the surface shape is calculated by flaw detection from a plurality of angles with respect to the surface shape, a strong reflected signal with respect to an ultrasonic beam hit from a direction close to a direction perpendicular to the inclined surface even if the surface is inclined Therefore, the measurement accuracy of the surface shape is improved.
Compared to the case where the surface shape is calculated by flaw detection only in one direction perpendicular to the surface of the subject, since the surface shape is emitted at a plurality of angles, a wide range of surface shapes can be measured at one time. spread.

Furthermore, since the surface shape is calculated by combining the flaw detection results using the reflection data of the beam with the maximum intensity extracted at each angle of emission, the surface has a high reflection intensity when estimating the surface shape (surface Therefore, the surface shape accuracy is improved.
As a result, the calculation accuracy of the ultrasonic wave emission delay time of each transducer 9 is improved so as to focus at a predetermined position inside the subject 7, and the flaw detection accuracy is improved.

(Second Embodiment)
Next, with respect to the synthesis method described in the first embodiment, a second embodiment of a different method will be described with reference to FIGS.
The surface shape calculation means 22 controls the operation of the transmission control means 15 and the reception control means 17 so that the surface measurement based on the flaw detection angle X1 (for example, 10 degree flaw detection) as shown in FIG. The ultrasonic beam is emitted at a plurality of angles so that the surface measurement by the vertical shown in FIG. 5 and the surface measurement by the flaw detection angle X2 (for example, −10 degree flaw detection) shown in FIG. The reflection data is received by the reception control means 17 and stored in the waveform memory 25. This configuration is the same as that of the first embodiment.

Then, as shown in the control flow diagram of FIG. 6, first, in step S21, the surface shape is measured at a typical flaw detection angle. For example, the vertical surface measurement result in FIG. 5B is set as the reference surface shape. In the next step S23, the surface is adjusted and corrected so that the surface becomes a smooth curve. That is, an extreme signal due to noise or the like is corrected to obtain a smooth curve.
Next, in step S25, when the surface shape data based on the remaining flaw detection angle has a reflection intensity higher than that of the reference surface shape data, the data moves to a data having a high reflection intensity so as to form a smooth curve. B ′) surface shape data is calculated. Next, in step S27, the convergence is determined, and if not converged, the process returns to step S23, and steps S23 and S25 are repeated until convergence.

The convergence of step S27 is performed by performing steps S23 and S25 to determine whether or not the change in the surface shape data is small.
And when it determines with the determination result of step S27 having converged, the result is output as surface shape data of FIG.5 (D). When the reference surface shape is set as FIG. 5 (A), steps S23 and S25 are performed in the same manner as described above to calculate the surface shape of FIG. 5 (A ′), and the reference surface shape is shown in FIG. 5 (C). Is set, step S23 and S25 are performed to calculate the surface shape of FIG.

  Thus, according to the second embodiment, the synthesis of the surface shape data for each flaw detection angle is set with the measurement result of any flaw detection angle as the reference surface shape, and the remaining surface shape data is the reference surface shape. When the reflection intensity is higher than the above data, the surface shape is calculated by moving to the high reflection intensity data so as to form a smooth curve. Therefore, the reflection is extremely strong due to noise without simply synthesizing the surface shape data. By correcting the change in the portion and synthesizing with a smooth shape, accurate and highly accurate surface shape data can be obtained.

  Furthermore, each surface shape data at each flaw detection angle is set as a reference surface shape, and correction and movement are repeated with other surface shape data to calculate the surface shape data and determine whether each surface shape data has converged. Thus, it is possible to obtain a highly accurate surface shape reflecting a plurality of surface shape data obtained by a plurality of emission angles.

(Third embodiment)
Next, instead of controlling and processing the plurality of vibrators 9 described in the first embodiment by the phased array method, the surface shape calculation unit 22 controls the output and reception signals by the aperture synthesis processing method. A third embodiment for calculating the surface shape will be described with reference to FIGS.
In the aperture synthesis processing method, an ultrasonic beam is transmitted by one transducer 9 among a plurality of transducers 9 and received by all the other transducers 9 and synthesized in consideration of the phase. Furthermore, this is a technique for obtaining high measurement accuracy by performing transmission at the positions of all the transducers 9 and combining them.

  FIG. 7 shows an outline of emission and reflection of an ultrasonic beam when the aperture synthesis processing method is used, and FIG. 8 shows a control flow diagram. As shown in FIG. 8, first, in step S31, one transducer is selected and an ultrasonic wave is transmitted. As shown in FIG. 7, the transmission beam spreads from the vibrator 9 and is emitted. In the next step S33, the reflected beam is received by all other receiving transducers, and data is acquired. In step S35, it is determined whether or not ultrasonic waves have been transmitted by all transducers. If not, the flow returns to step S31 to transmit ultrasonic waves and repeats until ultrasonic waves are transmitted by all transducers. That is, as shown in FIGS. 7A, 7 </ b> B, and 7 </ b> C, the transmission vibrator is moved and repeated until all the vibrators transmit. Note that transmission / reception control of the transmission vibrator and the reception vibrator is performed by the transmission control means 15 and the reception control means 17.

  When ultrasonic waves are transmitted by all the transducers, a range to be imaged is designated at step S37, and a point to be imaged within the range is designated at step S39. In the next step S41, one transmitting transducer is selected and the distance to the imaging point is calculated. In step S43, one receiving transducer is selected and the distance to the imaging point is calculated. In step S45, the propagation time is calculated from the two distances and the sound speed, and the data is added. That is, the data acquired by other receiving transducers are added together.

In step S47, it is determined whether all reception transducers have been selected and added. If not, the process returns to step S43 and repeats.
If all the receiving transducers have been selected in step S47, the process proceeds to step S49 to determine whether all the transmitting transducers have been selected. If not, the procedure returns to step S41 and repeats.
If all the transmitting transducers have been selected in step S49, the process proceeds to step S51 to determine whether images have been imaged at all positions. If not, the process returns to step S39 and repeats, and at all positions in step S51. If it has been imaged, the process ends and the image data is adopted as surface shape data.

  As described above, according to the third embodiment, the transmission timing and the reception timing of each of the plurality of transducers are controlled by the aperture synthesis processing method, and a plurality of images are acquired and the data is added to obtain the accuracy. High surface shape data can be calculated.

(Fourth embodiment)
Next, a fourth embodiment in which the surface shape is calculated by the surface shape calculating means 22 will be described with reference to FIGS.
FIG. 9 shows an outline of the emission and reflection of the ultrasonic beam. A plurality of transducers 9 are controlled by a phased array method to form a plurality of vertical beams.

FIG. 10 shows a control flow diagram. As shown in FIG. 10, first, in step S61, ultrasonic waves are transmitted with a plurality of vertical beams focused at positions at arbitrary depths from the surface. That is, the transmission beam is emitted from the vibrator 9 as shown in FIG.
In the next step S63, the surface shape obtained as a flaw detection result is measured as shown in FIG. 9B.
Next, in step S65, as shown in FIG. 9C, the focusing position is changed to the surface position obtained in the previous step S63, and in step S67, flaw detection is performed at the changed focusing position.
In step S69, as shown in FIG. 9D, the surface shape obtained as the flaw detection result is measured.
Next, in step S71, when the surface shape data at the time of the previous flaw detection and the surface shape data at the time of the current flaw detection are compared and it is determined that they have converged and matched, the processing ends and the surface shape data is adopted.
If it is determined that the images do not match and have not converged, the process returns to step S65, the focus position is changed based on the surface position of the previous measurement, flaw detection is performed again, and the process is repeated until the surface shape data converge and match. .

As described above, according to the fourth embodiment, it is easy to calculate the distance between the subject 7 and the transducer 9 or to repeat the flaw detection by installing the sensor at an arbitrary position without specifying the installation position. The surface shape can be calculated and the measurement accuracy of the surface shape is improved.
In the fourth embodiment, a surface shape with higher accuracy can be calculated by combining with the first embodiment. That is, although the vertical beam has been described in the fourth embodiment, a surface shape with higher accuracy can be calculated by using beams from a plurality of angles.

(Fifth embodiment)
Next, a fifth embodiment for improving the accuracy of the surface shape of the present invention will be described with reference to FIGS.
In order to focus the ultrasonic beam on a predetermined position inside the subject 7, it is necessary to calculate the delay time for operating the transducer 9 constituting the probe 11 with high accuracy. Is calculated using Snell's law based on the speed of sound in water, the speed of sound in the subject, the incident angle of the ultrasonic wave on the surface boundary position of the subject, and the refraction angle.

  In the fifth embodiment, as shown in FIG. 11, the metal temperature of the molten metal part at the welded portion of the specimen 7 is detected by the specimen temperature detecting means 52 and the inside of the molten metal part based on the detected temperature. And a sound speed measuring means 56 for actually measuring the sound speed in water, the sound speed value in the molten metal from the sound speed correcting means 54 and the sound speed value in water. Is input to the delay calculation means 20.

  Specifically, as shown in FIG. 12, the sound velocity measuring means 56 attaches a flat plate 58 to a position where the distance from the vibrator 9 is known, and measures the sound velocity from the propagation time in water.

  As described above, according to the fifth embodiment, the sound speed in the metal whose sound speed is likely to change depending on the temperature is corrected by the sound speed correcting means 54 based on the temperature. Since the measurement result is measured by the sound velocity measuring means 56 and the result is used, the refractive index can be calculated using the accurate sound velocity, and the ultrasonic emission delay time of each transducer is calculated so as to be focused at a predetermined position inside the subject. The accuracy is improved, and the flaw detection accuracy by the adaptive UT method is improved.

  According to the present invention, the accuracy of the adaptive UT method in which flaw detection is performed on a portion where the overlay shape is complicated, such as a welded portion of a pipe that penetrates the subject at a certain angle, improves reliability. Therefore, it is useful when applied to an ultrasonic flaw detector or a flaw detection method for a complicated shape such as a welded portion between a reactor vessel and a nozzle.

It is a schematic explanatory drawing which shows the installation state of the probe of this invention, (A) shows the state which the pipe | tube penetrated perpendicularly to the steel plate, (B) is sectional drawing of the state which the pipe | tube penetrated diagonally to the steel plate. is there. It is a block diagram of the control device in the first embodiment. It is explanatory drawing which shows the state of the ultrasonic beam of 1st Embodiment. It is a flowchart which shows the synthesis | combining method of 1st Embodiment. It is explanatory drawing which shows the state of the ultrasonic beam of 2nd Embodiment. It is a flowchart which shows the synthesis | combining method of 2nd Embodiment. It is explanatory drawing which shows the state of the ultrasonic beam of 3rd Embodiment. It is a flowchart which shows surface shape calculation of 3rd Embodiment. It is explanatory drawing which shows the state of the ultrasonic beam of 4th Embodiment. It is a flowchart of surface shape calculation of 4th Embodiment. FIG. 10 is an overall control block diagram illustrating a fifth embodiment. It is explanatory drawing which shows the sound speed measurement means in 5th Embodiment. It is explanatory drawing which shows the circumference | surroundings of a pipe | tube when a pipe | tube is penetrated with a certain angle in a steel plate. (A) Explanatory drawing showing that the refraction direction of the ultrasonic wave entering the subject is different from the intended direction, and (B) and (C) are explanatory diagrams of the adaptive UT method (adaptive ultrasonic flaw detection method).

Explanation of symbols

7 Welded part (subject)
9 transducer 10 control device 11 probe 15 transmission control means 17 reception control means 19 shape data calculation means 20 delay calculation means 21 shape calculation unit 22 surface shape calculation means 23 shape memory 25 waveform memory 52 subject temperature detection means 54 sound speed Correction means 56 Sound speed measurement means

Claims (5)

A phased array probe in which a plurality of transducers that emit ultrasonic waves are arranged on the subject is opposed to the subject, and the ultrasonic waves emitted from the transducers are predetermined inside the subject based on the shape of the subject surface. calculates the ultrasonic emission delay time of each transducer to focus on the position, the an ultrasonic flaw detection apparatus which performs flaw detection by focused ultrasound at a predetermined position of the subject,
Transmission control means for supplying ultrasonic waves to the vibrator, reception control means for receiving ultrasonic waves reflected from the subject via the vibrator , and ultrasonic waves received from the reception control means for the transmission control is controlled by means and said reception control means with a plurality of calculating the surface shape data of a predetermined range of the subject, the surface shape calculating means for calculating the surface shape of the subject by synthesis of the surface shape data of the plurality of the equipped,
The surface shape calculation means controls the emission timing of the ultrasonic waves from the transmission control means to emit light at a plurality of angles to the subject, and a plurality of surface shapes obtained by signals emitted at the plurality of angles The surface shape of the subject is calculated by synthesizing the data, and the synthesis sets one of a plurality of surface shape data obtained at the emission of each angle as a reference surface shape, and the remaining surface shape data is The ultrasonic flaw detector according to claim 1, wherein when the reflection intensity is higher than the reference surface shape data, the surface shape is calculated by moving to the data having a high reflection intensity so as to form a smooth curve . The ultrasonic flaw detector according to claim 1, wherein the subject is a welded portion having a built-up shape .
Transmission control means for supplying ultrasonic waves to the vibrator, reception control means for receiving ultrasonic waves reflected from the subject via the vibrator, and the inside of the subject based on the temperature of the subject at the welding site A plurality of surface shape data in a predetermined range of the subject by controlling the ultrasonic velocity corrected by the ultrasonic velocity and the ultrasonic wave corrected by the sound velocity correcting unit by the transmission control unit and the reception control unit. as well as, it comprises a surface shape calculating means for calculating the surface shape of the subject by synthesis of the surface shape data of the plurality of,
The surface shape calculation means controls the emission timing of the ultrasonic waves from the transmission control means to emit light at a plurality of angles to the subject, and a plurality of surface shapes obtained by signals emitted at the plurality of angles The surface shape of the subject is calculated by synthesizing the data, and the synthesis sets one of a plurality of surface shape data obtained at the emission of each angle as a reference surface shape, and the remaining surface shape data is The ultrasonic flaw detector according to claim 1, wherein when the reflection intensity is higher than the reference surface shape data, the surface shape is calculated by moving to the data having a high reflection intensity so as to form a smooth curve . The surface shape calculation means calculates and calculates the surface shape of the subject from a plurality of surface shape data by controlling and processing the emission signal from the transmission control means and the reception signal from the reception control means by an aperture synthesis processing method. The ultrasonic flaw detector according to claim 1 or 2 . The surface shape calculation means arbitrarily sets the depth of the focused position of the outgoing beam for flaw detection, changes the depth of the new focus position to the surface shape obtained as a result of the flaw detection, performs flaw detection, and again sets the surface shape. Measure, compare the surface shape data again with the previously calculated surface shape data, repeat the change of the depth of the focusing position until the surface shape no longer changes, and determine the shape when the change no longer occurs ultrasonic flaw detector according to claim 1 or 2, wherein the composed configured to calculate as the surface shape of. A phased array probe in which a plurality of transducers that emit ultrasonic waves are arranged on the subject is opposed to the subject, and the ultrasonic waves emitted from the transducers are predetermined inside the subject based on the shape of the subject surface. calculates the ultrasonic emission delay time of each transducer to focus on the position, the an ultrasonic flaw detection method for performing flaw detection by focused ultrasound at a predetermined position of the subject,
By controlling the emission timing of the ultrasonic wave transmitted from each of the plurality of transducers to emit at a plurality of angles with respect to the subject, the light is emitted at the plurality of angles with respect to a predetermined range of the subject. A plurality of surface shape data are calculated from the obtained signals, and the surface shape of the subject is calculated by combining the plurality of surface shape data, and the combining is performed on a plurality of surfaces obtained at each angle of emission. Any one of the shape data is set as a reference surface shape, and when the remaining surface shape data has a higher reflection intensity than the reference surface shape data, the data having a higher reflection intensity is moved to form a smooth curve. An ultrasonic flaw detection method characterized in that the surface shape is calculated .

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