JP5840910B2 - Ultrasonic flaw detection method - Google Patents

Description

The present invention relates to an ultrasonic flaw detection how, in particular, using a remote scanning mechanism and the array probe, relates to suitable ultrasonic flaw detection methods from performing ultrasonic flaw detection, such as weld metal material.

  In order to evaluate the soundness of a structure, an ultrasonic flaw detection method is widely used as a nondestructive inspection method for the surface and the inside of a structure (for example, a welded portion of a metal material). When it is difficult to directly access the structure to be examined, a remote scanning mechanism such as a scanner, manipulator, or vehicle is used, and this remote scanning mechanism automatically scans the position of the ultrasonic probe (AUT: Automated Ultrasonic Testing).

  Between the ultrasonic probe and the normal subject, the structure is inspected via an intermediate medium in order to improve the transmission of ultrasonic waves. As an intermediate medium, a liquid (for example, glycerin, machine oil, water, etc.) is widely used. In special cases, a gas or a highly viscous gel substance may be used as the intermediate medium. In particular, when there is a change in shape such as curvature or swell on the surface of the subject, a flaw detection method called “water immersion method” through an intermediate medium such as water is applied.

  Here, the sound speed of the subject is about 6000 m / s when the subject is, for example, a steel material, and the sound speed of the intermediate medium is about 1500 m / s, for example, when the subject is water. The sound speed of the medium is slow. For this reason, when the surface is a curved surface, the refraction phenomenon of the ultrasonic wave on the surface of the subject shape may cause a decrease in sensitivity.

  Therefore, in order to mitigate this effect, it is known to provide an acoustic lens with a material having a sound speed between that of the subject and that of the intermediate medium (for example, a synthetic resin such as acrylic having a sound speed of about 2700 m / s). (For example, refer to Patent Document 1).

  When inspecting a structure that is an object using an ultrasonic probe equipped with an acoustic lens, a part of the acoustic lens installed on the ultrasonic probe is in contact with the object at the inspection stage. The inspection is performed while keeping the distance between the subject and the ultrasonic probe.

  However, in the process up to the contact between the subject and the acoustic lens, it is necessary to use the remote scanning mechanism to bring the acoustic lens installed on the ultrasound probe closer to the subject surface (position adjustment). It becomes.

On the other hand, as a kind of ultrasonic flaw detection method, there is a so-called phased array type ultrasonic flaw detection method. Here, the phased array system, also called a scan type or electronic scanning method, for example, a plurality of ultrasonic sound Namioku receiving element probe arranged in an array composed of a piezoelectric element, a so-called array probe Using the electrical signal that triggers the generation of ultrasonic waves to each element of the array probe with a predetermined time delay, the ultrasonic waves generated from each element are superimposed to form a composite wave, Conditions such as the transmission angle and reception angle of ultrasonic waves to the inspected object, the transmission position and reception position, or the position where the combined wave interferes and strengthens energy, that is, the focal position, are changed at high speed by electrical control. It is an ultrasonic flaw detection method that made it possible. Here, a predetermined combination of delays given to each element is referred to as a delay pattern.

  The reason for electrically scanning the flaw detection conditions using the array probe in this way is that the ultrasonic transmission / reception angular position and focus can be freely changed over a wide inspection range. This is because by selecting an angle, a position, and a focal point at which a reflected wave from a body reflection source (such as a defect) can be received more strongly, a defect that is a reflection source can be easily found. As a typical combination of delay patterns, there is a sector scan method in which the transmission angle and the reception angle are changed. The sector scan method is characterized in that it can be visualized as a cross-sectional image of a subject from signals obtained at different angles, and it is easy to identify the position and properties of a reflection source.

  Thus, in order to obtain a more accurate and reliable flaw detection result, among the positional relationship between the array probe and the subject, in particular, the ultrasonic incident position (the array probe and the subject surface) on the subject. It is necessary to adjust the angle between the two.

  In order to perform mutual position adjustment between the array probe and the object surface, position adjustment in a state where the acoustic lens and the object surface are not in contact is necessary. The reason for this is to avoid interference between the inspection device such as the probe and the inspection object in consideration of the possibility that the accurate positional relationship of the object cannot be grasped when inspecting the object with the remote scanning mechanism. In addition, the inspection apparatus is installed in a positional relationship that does not sufficiently contact as an initial position.

  When an ultrasonic probe equipped with an acoustic lens is brought into contact with the subject and scanned by a remote control mechanism, the condition of the ultrasonic wave incident on the subject (angle of the probe relative to the subject surface, Before the probe is pressed against the subject surface in a state where the distance) is constant, a means for adjusting the positional relationship of the ultrasonic probe with the subject surface is required.

  For example, according to Patent Document 1, when an internal probe is used to detect an object with an array probe including an acoustic lens, an element group used for transmission is used to avoid reverberation due to multiple reflected waves in the acoustic lens. A transmission / reception division method is used in which element groups used for reception are separately used.

  Regarding the position adjustment of the ultrasonic probe, for example, it is input and stored in advance as shape data of the curved surface shape of the subject, and the position and direction of the ultrasonic probe are detected based on the stored data. An ultrasonic flaw detection method is known in which an incident point on the surface of a specimen is held at a constant angle and a constant distance (see, for example, Patent Document 2).

  Further, in order to maintain the distance and angle between the subject and the ultrasonic probe, an automatic ultrasonic flaw detector that measures the shape of the subject with a distance measuring probe in advance is used, and the subject and the ultrasonic probe are included therein. A probe for ultrasonic flaw detection is known as a distance sensor for measuring the distance of the probe (see, for example, Patent Document 3).

  Also, in ultrasonic flaw detection using an array probe, the surface shape of the subject is measured using the array probe, the delay time given to the array probe is calculated from the surface shape data, and the complex shape portion However, a flaw detection apparatus that focuses at a predetermined position is known (see, for example, Patent Document 4).

JP 2010-281843 A JP-A 63-309853 JP-A-1-292248 JP 2008-122209 A

  However, when the inside of a subject is flawed with an array probe having an acoustic lens described in Patent Document 1, when the position of the subject surface and the array probe is adjusted, the probe is installed on the array probe. The acoustic lens thus made is not in contact with the subject surface. For this reason, the propagation path cannot be received by the receiving array probe after the ultrasonic wave transmitted from the transmitting array probe is reflected on the surface of the subject. Therefore, there may be a case where the position of the array probe that is not in contact with the subject surface cannot be adjusted using the reflected wave from the subject surface. Therefore, in this case, the position of the subject surface and the array probe cannot be adjusted.

  Moreover, in the thing of patent document 2 and patent document 3, although there exists description regarding the prior setting for keeping the positional relationship (angle and distance) of a test object and an ultrasonic probe constant, how is it by actual flaw detection? It is impossible to specify whether or not the positional relationship has been established.

  Further, in Patent Document 4, there is a description regarding setting of flaw detection conditions in consideration of the surface shape of the subject. However, in automatic flaw detection (AUT), the positional relationship between the array probe and the subject (angle and distance). Cannot be specified.

The object of the present invention is to propagate an ultrasonic wave through an intermediate medium such as water using an array probe provided with an acoustic lens, and bring a part of the array probe into contact with the surface of the subject. Using the phased array method, when the ultrasonic probe is scanned by the remote scanning mechanism for ultrasonic flaw detection, the flaw detection inside the subject and the positional adjustment that accurately identifies the positional relationship between the array probe and the subject are performed. by both, small deviation of the positional relationship of the array probe and the object is to provide a more capable accurate ultrasonic flaw ultrasonic testing how.

( 1 ) In order to achieve the above object, the present invention propagates an ultrasonic wave transmitted from an ultrasonic probe including an array probe to a subject via an acoustic lens and a medium, and a remote scanning mechanism. An ultrasonic flaw detection method for scanning the ultrasonic probe using an ultrasonic probe, and capable of scanning the ultrasonic probe with respect to the subject at a predetermined distance and angle using an ultrasonic transmission / reception device Teaching of the probe position is performed so that the teaching transmits ultrasonic waves to the medium, receives a reflected wave from the surface of the subject as a first received signal, the flaw detection image by the received signal, and displayed and recorded as a first acoustic image using the acoustic velocity of the medium, the so as to obtain the surface profile of the object, the surface of the subject obtained by the teaching favorable profile Based on Le, said to keep the ultrasound probe to the subject at a predetermined distance and angle by the drive control unit, the flaw detection of the subject was performed using the ultrasonic transmitting and receiving apparatus, the object to be In the specimen flaw detection, an ultrasonic wave is transmitted to the inside of the subject through the medium, a reflected wave from the inside of the subject is received as a second reception signal, and a flaw detection image by the second reception signal is received. Is recorded and displayed as a second acoustic image using the sound velocity of the subject, and simultaneously with or switching, a reflected wave from the surface of the subject is received as a first received signal, and the first A flaw detection image based on one received signal is displayed as a first acoustic image using the speed of sound of the medium .
By this method, both the flaw detection inside the subject and the position adjustment for accurately identifying the positional relationship between the array probe and the subject are achieved, and the positional relationship between the array probe and the subject is less misaligned and more accurate. Ultrasonic flaw detection becomes possible.

( 2 ) In the above ( 1 ), preferably, the array probe includes first and second array probes each including two element groups, and at least one of the first and second array probes. One side is used for both transmission and reception, a reflected wave from the surface of the subject is received as a first reception signal, displayed as the first acoustic image, and one of the first and second array probes for transmission to Kano one, and set the other as a receiver, receives a reflected wave from the inside of the subject as a second reception signal is obtained by the displayed as the second acoustic image.

According to the present invention, both the flaw detection inside the subject and the positional adjustment for accurately specifying the positional relationship between the array probe and the subject are compatible, and the positional relationship between the array probe and the subject is small. More accurate ultrasonic flaw detection is possible.

It is a block diagram of the ultrasonic flaw detector by one Embodiment of this invention. It is operation | movement explanatory drawing of the remote scanning mechanism used for the ultrasonic flaw detector by one Embodiment of this invention. It is a block diagram which shows the structure of the ultrasonic transmitter / receiver used for the ultrasonic flaw detector by one Embodiment of this invention. It is explanatory drawing of a structure of the array probe used for the ultrasonic flaw detector by one Embodiment of this invention. It is explanatory drawing of the flaw detection method by the ultrasonic flaw detector by one Embodiment of this invention. It is explanatory drawing at the time of implementing an ultrasonic flaw detection method by a phased array method through intermediate media, such as water, with the array probe which installed the acoustic lens. It is explanatory drawing of the flaw detection method by the ultrasonic flaw detector by one Embodiment of this invention. 1 is an overall configuration diagram of an ultrasonic flaw detection system using an ultrasonic flaw detection apparatus according to an embodiment of the present invention. It is a flowchart which shows the content of the ultrasonic flaw detection method by the ultrasonic flaw detector by one Embodiment of this invention. It is a flowchart which shows the content of the ultrasonic flaw detection method for depth sizing by the ultrasonic flaw detector by one Embodiment of this invention. It is explanatory drawing of the setting method of the teaching data in the ultrasonic flaw detection method by one Embodiment of this invention. It is explanatory drawing of the relationship between the sensor and the subject in the ultrasonic flaw detection method. It is explanatory drawing of the relationship between the sensor and the subject in the ultrasonic flaw detection method. It is explanatory drawing of the relationship between the sensor and the subject in the ultrasonic flaw detection method. It is explanatory drawing of the relationship between the sensor and the subject in the ultrasonic flaw detection method. It is explanatory drawing at the time of implementing an ultrasonic flaw detection method by a phased array method through intermediate media, such as water, with the array probe which installed the acoustic lens. It is explanatory drawing at the time of implementing an ultrasonic flaw detection method by a phased array method through intermediate media, such as water, with the array probe which installed the acoustic lens.

  Hereinafter, the contents of an ultrasonic flaw detection method using the ultrasonic flaw detection apparatus according to an embodiment of the present invention will be described with reference to FIGS. Here, an example using the sector scan method among the phased array method using the array probe will be described.

First, the configuration of the ultrasonic flaw detector according to the present embodiment will be described with reference to FIG.
FIG. 1 is a configuration diagram of an ultrasonic flaw detector according to an embodiment of the present invention.

  The subject 101 shows an example of a welded portion having a complex shape portion, and is obtained by penetrating a tube 101B through a steel plate 101A at a predetermined angle. The periphery of the pipe 101B where the pipe 101B and the steel plate 101A are close to each other is welded to form a welded part 101C.

  The subject 101 is disposed in the container CH, and water is stored in the container. That is, the subject 101 is placed in water. Accordingly, water is used as a medium for propagating ultrasonic waves from the array probe 100 as ultrasonic transmission / reception means to the subject 101, and inspection of the presence or absence of scratches on the welded portion 101C by ultrasonic flaw detection using a water immersion method. Measure the dimensions of the wound.

  Here, the shape of the welded part 101C changes three-dimensionally depending on the angle in the circumferential direction of the tube 101B, and has a feature of a saddle shape in which concave and convex surfaces are combined, and the ultrasonic wave is accurately applied to the target position. It has a shape that is difficult to enter.

  Here, the application destination of this example is, for example, a defect in a welded portion 101C (for example, a control rod drive mechanism stub tube, an in-core instrumentation nozzle housing, a shroud support, a shroud, etc.) of a reactor internal structure of a nuclear power plant. Non-destructive inspection for detection and dimensional measurement. In addition, the method and procedure described in this example can be similarly applied to a pipe or a plate-shaped inspection object in addition to the curved surface characteristic of the in-furnace structure.

Array probe 100, liquid above the inspection surface of the object 101 (e.g., water) is placed through the, by a drive signal supplied from the ultrasonic transmitting and receiving apparatus 104, the ultrasonic wave transmitting and receiving surface or al ultrasound It is generated and propagated toward the subject 101, a reflected wave appearing from the surface or inside of the subject 101 is detected, and a received signal is input to the ultrasonic transmission / reception apparatus 104.

  The array probe 100 is divided into a first array probe 100A and a second array probe 100B. Furthermore, the ultrasonic transmission surfaces of both the array probes 100A and 100B are provided on the ultrasonic transmission surfaces. An acoustic lens 100C is provided.

  When the reflection source 103 such as a crack exists in the welded part 101 </ b> C, the reflected wave from the crack 103 is received by the array probe 100.

  The array probe 100 is connected to the ultrasonic transmission / reception device 104 and is displayed as flaw detection result information on the acoustic image display means 105. The array probe 100 is attached to the remote scanning mechanism 102 and moves to a predetermined position to perform flaw detection.

The acoustic image display means 105 includes a display unit 105A and a display unit 105B. The display image of the display unit 105A will be described later with reference to FIG. 5, but a reflection image from the subject surface 101D is obtained and information on the surface profile of the welded part 101C is obtained. The display image of the display unit 105B will be described later with reference to FIG.

  The drive control device 110 controls the remote scanning mechanism 102 based on the surface profile information of the welded portion 101C detected by the ultrasonic transmitting / receiving device 104, so that the array probe 100 is applied to the surface of the welded portion 101C. Thus, a predetermined angle is set at a predetermined distance.

Next, the operation of the remote scanning mechanism 102 used in the ultrasonic flaw detector according to the present embodiment will be described with reference to FIG.
FIG. 2 is an explanatory view of the operation of the remote scanning mechanism used in the ultrasonic flaw detector according to one embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts.

  In order to scan the array probe 100 three-dimensionally, for example, a remote scanning mechanism 102 having six or more control axes used for an automatic robot, a manipulator, or the like is used.

  The remote scanning mechanism 102 is, for example, a head having three rotation axes of θx, θy, and θz that rotates about the array probe 104 as rotation axes in the directions of the X, Y, and Z axes. Consists of a part 102A and three axes Z, R, and φ, which are seated on the pipe 101B and move the entire head unit 102A, up and down (H axis), radial direction (R axis), and rotation axis (φ axis) Is done. The array probe 100 can be moved by the remote scanning mechanism 102.

Next, the configuration of the ultrasonic transmission / reception apparatus 104 used in the ultrasonic flaw detection apparatus according to the present embodiment will be described with reference to FIG.
FIG. 3 is a block diagram showing a configuration of an ultrasonic transmission / reception apparatus used in the ultrasonic flaw detection apparatus according to the embodiment of the present invention.

  The transmission / reception device 104 includes a computer 104A, a time control unit 104B, a pulsar 104C, a receiver 104D, a data recording unit 104E, and a storage unit 104F. The pulser 104C supplies a drive signal to the array probe 100 shown in FIG. 1, and a receiver 104D processes a reception signal input from the array probe 100.

  Here, the computer 104A controls the time control unit 104B, the pulsar 104C, the receiver 104D, and the data recording unit 104E so as to obtain necessary operations.

  First, the element group setting unit 104G sets one of transmission-only, reception-only, and transmission / reception for the two element groups 100A and 100B into which the array probe is divided. The time control unit 104B controls the timing of the drive signal output from the pulser 104C and also controls the input timing of the reception signal by the receiver 104D. Thus, the reception signal from the receiver 104C is sequentially stored in the data recording unit 104E in synchronization with the transmission signal.

  The data recording unit 104E functions to process the received signal supplied from the receiver 104D and supply it to the acoustic image display unit 105. Here, the operation of the acoustic image display unit 105 will be described in detail later.

  The storage unit 104F stores, for example, a delay pattern of a delay time for sector scanning.

Next, the configuration of the array probe 100 used in the ultrasonic flaw detector according to the present embodiment will be described with reference to FIG.
FIG. 4 is an explanatory diagram of the configuration of the array probe used in the ultrasonic flaw detector according to one embodiment of the present invention. 4A is a bottom view, FIG. 4B is a front view, and FIG. 4C is a side view.

  FIG. 4 schematically shows the most basic configuration of the array probe 100. The array probe 100 includes an array probe 100A of the first element group and an array probe 100B of the second element group, and each element group is an ultrasonic transmission / reception arrayed in a line. An element 1202 is used.

  The ultrasonic transmission / reception element 1202 includes a piezoelectric conversion element such as a piezoelectric ceramic, a piezoelectric polymer, or a piezoelectric composite material. The ultrasonic transmission / reception element 1202 includes a front plate 1203 for protecting the ultrasonic transmission / reception element and adjusting acoustic matching by multiple reflection, and is in contact with the acoustic lens 100C outside. The outside of the array probes 100A and 100B and the acoustic lens 100C is filled with a medium (water or the like). The center position 1201 of the ultrasonic transmission / reception surface is treated as a representative point as a transmission / reception point of the array probe as necessary during display or evaluation. The array probe 100 is connected to the transmission / reception device 104 shown in FIG. 1 by a cable.

  The material of the acoustic lens 100C is, for example, a synthetic resin (acrylic, polyimide, polystyrene, etc.), and the subject (stainless steel, sonic velocity Vs = 5800 m / s) and the surrounding medium (water, sonic velocity Vw = 1500 m / s). ) Has a sound speed of 2000 to 3000 m / s, which is the middle of the above.

For this reason, when an ultrasonic wave is directly incident on a subject (metal) such as stainless steel from a medium such as water, the sound velocity ratio is large. Therefore, as shown in the following equation (1), the incident angle θw from the medium However, the ultrasonic wave is greatly refracted in the subject, and the angle θw inside the subject changes greatly.

θs = sin ⁻¹ (sin θw × Vs / Vw) (1)

As shown in Patent Document 1, the acoustic lens has a function of relaxing the refraction phenomenon between the medium and the subject. In particular, when the subject surface has a concave surface, the energy of ultrasonic waves is concentrated on the subject surface. This has the effect of alleviating the effect and propagating ultrasonic waves to the inside of the subject.

  However, if an acoustic lens is installed on the array probe, ultrasonic waves are multiple-reflected in the acoustic lens, and the reverberation remains, which may reduce the signal-to-noise ratio of the reflected wave signal from the inside of the subject to be originally obtained. is there. Therefore, when an acoustic lens that relieves the refraction phenomenon caused by a curved surface is adopted, the acoustic lens is divided into two regions by a sound insulating plate 1204 such as cork or rubber, and the array probe is also divided into two regions. Dividing into element groups, one element group (and acoustic lens) is used for transmission, and the other element group (and acoustic lens) is used for reception, reducing the reverberation in the acoustic lens and improving the S / N ratio. The reflected wave from the inside of the subject can be received.

Next, the flaw detection method using the ultrasonic flaw detector according to the present embodiment will be described with reference to FIGS.
5 and 7 are explanatory diagrams of a flaw detection method using an ultrasonic flaw detector according to an embodiment of the present invention. FIG. 5 is a flaw detection screen using the sound speed of the medium. FIG. 7 is a flaw detection screen using the sound speed of the subject. FIG. 6 is an explanatory diagram in a case where an ultrasonic flaw detection method is performed by a phased array method through an intermediate medium such as water by an array probe in which an acoustic lens is installed.

  First, according to FIG. 5, the subject and the array probe at the stage of adjusting the position of the array probe in a state where the surface of the subject is not in contact with the acoustic lens provided in the array probe. The flaw detection screen using the sound speed of the medium (water in the water immersion method) will be described.

An ultrasonic wave 1301 is transmitted from the array probe 100 into a medium such as water. A delay pattern is set so that the propagation angle (incident angle) with respect to the medium changes from the array probe 100 to the subject 101, and ultrasonic waves are transmitted while changing the incident angle θi. For example, the range of change in incident angle is set to a 1 ° pitch (total of 121 angles) from −60 ° to + 60 °.

  Here, at least one of the element groups 100A and 100B constituting the array probe 100 is set to be used for both transmission and reception.

  The reason for setting for both transmission and reception will be described with reference to FIG.

  As shown in FIG. 6A, when the acoustic lens 100C is attached, two array probes are provided so that multiple reflected waves of ultrasonic waves in the acoustic lens do not affect the flaw detection signal. Is used for transmission and the other 100B is used for reception. At this time, the acoustic lens 100C is also divided into two areas of the transmission side and the reception side, and a sound insulating plate 100D made of cork or rubber is provided to acoustically cut off the transmission side and the reception side.

  When the array probes 100A and 100B on which the acoustic lens 100C is installed are in contact with the surface 601 of the subject, the sound insulating plate 104D functions effectively with respect to the reflected wave from the reflection source 602 inside the subject. Thus, it is possible to receive a reflected wave with a high S / N ratio with few multiple reflections.

  On the other hand, as shown in FIG. 6B, when adjusting the position of the subject surface and the array probe, the acoustic lens 100C installed on the array probes 100A and 100B is connected to the subject surface 601. It is in a non-contact state. For this reason, as indicated by the propagation path 603, the ultrasonic wave transmitted from the transmitting array probe 100A is not easily received by the receiving array probe 100B after being reflected by the subject surface 601. The ultrasonic wave received by the receiving array probe 100B is weak. Therefore, it is difficult to adjust the position of the array probe in a non-contact state with the subject surface using the reflected wave from the subject surface 601.

  Therefore, when adjusting the position of the subject surface and the array probe, at least one of the element groups 100A and 100B constituting the array probe 100 is set to be used for both transmission and reception.

  The following two methods will be described as examples of the method for setting for both transmission and reception.

  First, consider a case where N (total 2N) piezoelectric elements are arranged in each of the element group 100A and the element group 100B. Element numbers 1 to N are assigned as the element group 100A, and element numbers N + 1 to 2N are assigned as the element group 100B. When assigning an element group for both transmission and reception, the element number setting unit 104G sets the element number used for transmission to 1 to 2N, and sets the element number used for reception to 1 to 2N. This corresponds to a case where both the element groups 100A and 100B are set to be used for both transmission and reception. This first example is an example in which a transmission pulser and a reception receiver can drive a maximum of 2N piezoelectric elements.

  Second, for the element group 100A and the element group 100B, a signal φ_AA transmitted by the element group 100A and received by the element group 100A, a signal φ_AB transmitted by the element group 100A and received by the element group 100B, and the element group 100B The signal φ_BA transmitted by the element group 100A and received by the element group 100B and the signal φ_BB transmitted by the element group 100B and received by the element group 100B are added together, and transmitted simultaneously by the element group (A + B). A + B) is a method of synthesizing a waveform equivalent to the waveform received simultaneously. The signal φ_AB transmitted by the element group 100A and received by the element group 100B and the signal φ_BA transmitted by the element group 100B and received by the element group 100A are weak, but can be used when four signals are combined. This second example is an example in which a transmission pulser and a reception receiver can drive a maximum of N piezoelectric elements. Compared to the first case, the number of pulsers and receivers used can be halved. The switching between transmission and reception is the same as in the first example in that switching is performed by setting the element number in the element group setting unit 104G.

  The ultrasonic wave 1301 transmitted from the element group of the array probe 100 (both or one of the element groups 100A and 100B) is reflected by the object surface 101D and received by the array probe 100 again.

  At this time, if the element group used for transmission / reception is separated, as described with reference to FIG. 9, it is difficult to receive the reflected wave from the subject surface by the other element group that is not for transmission. . Therefore, at the stage of position adjustment, it is necessary to set an element group for both transmission and reception.

  The received signal is recorded in the data recording unit 104E of FIG. 3 as one waveform for each incident angle θi. The amplitude value of the point 1302B of the one-way propagation time T1 in the medium such as water obtained by subtracting the one-way propagation time T0 in the acoustic lens from the one-way propagation time of the reflected wave of the subject surface 101D is A (T1; θi). 1 is displayed in a fan shape with an angle θ1 and a propagation path (the product of the time T1 and the sound velocity of the medium) as shaded black and white or color pixels with the intensity of the amplitude value, so that the display unit 105A in FIG. As shown in FIG. 5, a flaw detection image 106A and a reflection image 106E from the subject surface 101D can be obtained.

  Since the thickness of the acoustic lens is known, the one-way propagation time T0 in the acoustic lens is also a known value.

Furthermore, the shape of the subject surface 101D can be identified from the image 106C of the waveform rising point 1302A among the reflected waves of the subject surface 101D.
Further, the distance between the array probe and the subject can be specified from the image 106C of the subject surface shape, from the distance 106D in the direction immediately below the sensor.

  In this way, by identifying the distance between the subject surface and the array probe and the shape of the subject surface below the array probe, while confirming the positional relationship between the subject surface and the array probe, The array probe can be brought into contact with the subject surface.

  By pressing the array probe against the subject using the automatic drive mechanism, the array probe can be brought closer to the subject surface while maintaining the positional relationship between the array probe and the subject surface facing each other. .

  Next, referring to FIG. 7, the surface of the subject and the acoustic lens provided in the array probe come into contact (or include a state where they are close to each other within a few millimeters that can be regarded as contact) to detect the inside of the subject. The flaw detection screen using the sound speed of the subject in the stage will be described.

  The flaw detection based on the sound speed of the subject and the flaw detection based on the sound speed of the medium (water, etc.) are set by, for example, switching the delay pattern based on the sound speed of the subject and the delay pattern based on the sound speed of the medium at the same time or switching. It can be realized.

  In the flaw detection using the sound velocity of the subject, one of the array probes 100A and 100B is dedicated to transmission and the other is dedicated to reception. This is because the surface of the subject is in contact with the acoustic lens provided in the array probe, so that the reflected wave of the ultrasonic wave transmitted from one array probe can be received by the other array probe. Because. Here, for example, the array probe 100A is used exclusively for transmission and the array probe 100B is used exclusively for reception. As a result, reverberation in the acoustic lens is reduced, and a reflected wave from the inside of the subject with improved SN ratio can be received.

  Ultrasonic waves 1401 are transmitted from the array probe 100A into a medium such as water via the acoustic lens 100C. From the array probe 100A, a delay pattern is installed so as to change the propagation angle (refraction angle) in the subject to the subject 100, and an ultrasonic wave having a changed refraction angle θj is transmitted. Note that the incident angle θj ′ from the array probe to the medium when propagating to the subject at θj is given by sin θj ′ = sin θj × (V ′ / V) according to Snell's law similar to Equation 1. . V ′ is the sound speed of a medium such as water, and V is the sound speed of the subject.

  The ultrasonic wave 1401 transmitted from the array probe 100A is refracted to the inside of the subject by the subject surface 101D, propagates into the subject, and is reflected when the reflection source 103 such as a defect exists in the subject. The signal reflected by the source 103 is refracted by the subject surface 101D and received by the array probe 100B.

  The received signal is recorded in the data recording unit 104E of FIG. 3 as one waveform for each refraction angle θj.

One-way propagation time obtained by subtracting one-way propagation time T0 in the acoustic lens out of the propagation time of the ultrasonic wave from the reflected wave of the reflection source 103 inside the subject in a state where the object surface and the acoustic lens are in contact with each other. Assuming that the amplitude value of the point 1402 of T2 is A (T2; θj), the angle θj and the propagation path (the product of the time T1 and the sound velocity of the subject) are used as a shaded black and white or color pixel having the amplitude value intensity. by displaying the fan, the display unit 105B of FIG. 1, it is possible, as shown in FIG. 7, to obtain a flaw detection image 106B corresponding to the cross section of the object.

When performing an automatic ultrasonic flaw detection (AUT) while controlling the position of the array probe (100A and 100B) with the remote scanning mechanism 102, for example, using a robot having six or more axes as shown in FIG. The probe position is scanned so that the angle and distance between the array probe and the subject are constant. Note that an acoustic lens exists between the array probe and the subject, and the distance between the array probe and the subject is set to the thickness of the acoustic lens, for example, about 10 to 20 mm.

  As described above, in the present embodiment, when an array probe including an acoustic lens is brought into contact with a curved object surface, the position adjustment of the array probe prior to the flaw detection inside the object is performed. In this stage, the two element groups constituting the array probe are switched for transmission and reception, and flaw detection at the sound velocity of the medium (water, etc.) existing between the array probe and the subject is performed simultaneously (or By switching, the reflected wave from the object surface can be received, the distance between the array probe and the object is specified, and the object shape directly under the array probe is specified. After specifying the object shape, after adjusting the positional relationship between the array probe and the object surface, the array probe can be brought into contact with the object surface, and two elements constituting the array probe It is also possible to divide the group into a transmitter and a receiver and perform ultrasonic flaw detection inside the subject by using the subject sound velocity that has been performed in the conventional ultrasonic examination.

  Thus, by identifying the mutual positional relationship of the array probe with respect to the subject surface, it becomes possible to more accurately evaluate the position of the reflection source, the measurement accuracy of the reflection source position, and the reflection source position. It is possible to provide a highly reliable inspection with high dimensional measurement accuracy.

Next, a specific example of the ultrasonic flaw detection method using the ultrasonic flaw detector according to one embodiment of the present invention will be described with reference to FIGS.
First, the overall configuration of the ultrasonic flaw detection system using the ultrasonic flaw detection apparatus according to the present embodiment will be described with reference to FIG.
FIG. 8 is an overall configuration diagram of an ultrasonic flaw detection system using an ultrasonic flaw detection apparatus according to an embodiment of the present invention.

  Here, as an example of the application target, an overall configuration of an ultrasonic flaw detection system in the case of applying to inspection of a welded portion of a reactor internal structure of a nuclear power plant is shown.

The objects to be inspected are various weld joints of the shroud 702 that is a structure in the reactor pressure vessel 701, a through-pipe welded portion 101B such as a control rod drive mechanism stub tube, and the like. On the operation floor 703, a work carriage 704 for ascending and descending equipment such as a multi-axis manipulator control device 705, an ultrasonic flaw detector 706, and various cables 707, which are the remote scanning mechanism 102, is installed. . The array probe 100 is installed in front of the multi-axis manipulator 102, and the probe is scanned by the multi-axis manipulator 102 so as to cover the examination region of the subject, and automatic flaw detection is performed.

  The ultrasonic flaw detector 706 includes the transmission / reception device 104 and the acoustic image display means 105 shown in FIG. The manipulator control device 705 includes the drive control device 110 shown in FIG.

Next, the contents of the ultrasonic flaw detection method using the ultrasonic flaw detector according to the present embodiment will be described with reference to FIG.
FIG. 9 is a flowchart showing the contents of the ultrasonic flaw detection method by the ultrasonic flaw detection apparatus according to the embodiment of the present invention.

  Here, the case of the inspection of the in-core structure weld of the nuclear reactor shown in FIG. 8 will be described.

  First, in step S101, the inspector performs a visual inspection with an underwater camera for the purpose of detecting a defect instruction.

  Thereafter, in step S102, the inspector performs an eddy current flaw detection as necessary to measure the opening length of the defect.

  Further, in step S103, the inspector uses the ultrasonic flaw detector according to the present embodiment to perform ultrasonic inspection (UT) for the purpose of depth measurement (depth sizing) of the detected defect. To implement.

  Thereafter, in step S104, the inspector performs defect progress evaluation, and in step S105, repairs and replacements are performed as necessary.

  The ultrasonic flaw detection method according to the present embodiment is applied by the depth sizing in step S103.

Next, the contents of the ultrasonic flaw detection method for depth sizing by the ultrasonic flaw detector according to the present embodiment will be described with reference to FIG.
FIG. 10 is a flowchart showing the contents of an ultrasonic flaw detection method for depth sizing by the ultrasonic flaw detector according to one embodiment of the present invention.

  First, calibration before flaw detection (step S201) is performed, and sensitivity, time axis, and the like are adjusted. Next, the apparatus is installed in the furnace (step S202), and the apparatus position (such as the origin of each axis) is initialized (step S203).

  Next, teaching of the position of the array probe (teaching of the initial value of the set value) is performed (step S204).

Next, a confirmation scan for confirming the teaching data is performed (step S205), whether there is any interference between the device or the like and the inspection device (remote drive device, probe, cable, etc.) positional relationship between the subject confirms whether it is appropriate, until the positional relationship between coherence confirmed probe and the object of the device is in a state no problem, teaching (step S204) and confirms the scan (step S205) is repeated.

  After confirming that there is no problem, the probe is moved to the flaw detection start position (step S206). After confirming the sensor installation state at the start position (step S207), flaw detection is started (step S208).

  During the flaw detection, it is confirmed whether there is any abnormality in the test data (step S209), the positional relationship between the probe and the subject (step S210), and finally whether the flaw detection range is covered. Confirmation (step S211) and if there is no problem, the flaw detection is terminated (step S212).

  After completion of the flaw detection, the apparatus is uninstalled from the furnace (step S213), and calibration after the flaw detection is completed (step S214).

  Here, for example, in the steps during the flaw detection (steps S208 to S212), when the positional relationship between the array probe and the subject is confirmed (step S210), the normal flaw detection using the subject sound velocity is performed. At the same time, the distance and angle (inclination of the subject) between the array probe and the subject are confirmed using the speed of sound of the medium (such as water) between the array probe and the subject.

  At this time, an acoustic image based on the sound velocity of the subject and an acoustic image based on the sound velocity of the medium (water, etc.) are displayed simultaneously (or switched), so that the positional relationship is confirmed while flaw detection is performed. By recording, the positional relationship can be recorded.

  By recording the positional relationship between the array probe and the subject, for example, after flaw detection, the distance and angle between the array probe and the subject can be specified, and when there is a deviation from the assumed value, It can be corrected and evaluated, and a highly reliable ultrasonic flaw detection can be provided.

  Further, for example, in teaching (step S204), which is a step before the flaw detection, simultaneously with the normal flaw detection using the object sound velocity, the sound velocity of the medium (water etc.) between the array probe and the object is used. As described above, appropriate teaching data (initial value) can be set while confirming the distance and angle (inclination of the subject) between the array probe and the subject.

  On the other hand, it is also important to record the positional relationship between the array probe and the subject. For example, when performing flaw detection without performing teaching (step S204), the positional relationship between the array probe and the subject can be recorded. In this case, there is little unevenness on the surface of the subject, and flaw detection can be performed without performing teaching (step S204). In this case, flaw detection is performed without performing teaching (step S204), and on the other hand, as a result of checking flaw detection data after the flaw detection is completed by recording the positional relationship between the array probe and the subject, the flaw detection data is suspicious. When there is an uncertain location, it is possible to confirm whether there is no abnormality in the distance and angle between the array probe and the subject by confirming the positional relationship between the array probe and the subject already recorded. When there is no abnormality in the angular distance, the data of the suspicious part can be considered as data due to defects inside the subject.

Next, a teaching data setting method in the ultrasonic flaw detection method according to the present embodiment will be described with reference to FIG.
FIG. 11 is an explanatory diagram of a teaching data setting method in the ultrasonic flaw detection method according to the embodiment of the present invention.

  The array probe 100 transmits an ultrasonic wave 2101 in a direction directly below it.

  The waveform reflected from the subject surface 101D is recorded in the data recording unit 104E in FIG. This waveform data includes information on the distance between the array probe 100 and the subject 101 and information on the angle between the array probe 100 and the subject 101.

As a received waveform, when the propagation time is taken on the horizontal axis and the absolute value of the amplitude is taken on the vertical axis, the maximum amplitude MAX_A (θx) of the reflected echo group 2105 from the subject surface 101D can be obtained. Here, θx represents the rotation axis of the remote scanning mechanism. θx is an example for explanation, and any of the drive shafts may be used in addition to the other rotation axes θy and θz.

  When the rotation axis θx is changed, the maximum amplitude MAX_A (θx) changes with respect to θx. At this time, when the maximum amplitude value is the maximum value (in the case of the sensor rotation angle 2102 in the display on the display unit 105C), it is confirmed that the array probe and the subject are facing each other (incident angle is 0 degree). Therefore, the value θx of the rotation axis that gives the directly facing condition where the ultrasonic wave is incident on the subject most efficiently can be obtained and set as the teaching value.

  Furthermore, since the position of the array probe in the normal direction (facing relationship) on the surface of the subject can be specified as necessary, the angle between the array probe and the subject can be adjusted.

Similarly, when the propagation time is taken on the horizontal axis and the absolute value of the amplitude is taken on the vertical axis as the received waveform, the speed of sound of the medium (water, etc.) is calculated during the one-way propagation time until the reflection echo group 2105 rises from the subject surface. Is multiplied by the distance R (θx). The rise of the echo can be automatically obtained as the intersection of the time gate signal 2106 and the waveform 2105. Θx represents the rotation axis of the remote scanning mechanism. θx is an example for explanation, and any of the drive shafts may be used in addition to the other rotation axes θy and θz.

  When the rotation axis θx is changed, the distance R (θx) changes with respect to θx. For example, when it is desired to set the distance R0, the value of the distance R (θx) closest to the distance R0 (in the case of the sensor rotation angle 2103 in the display on the display unit 105D) or the difference between the distance R0 and the distance R (θx) The θx at which the absolute value is the minimum value can be set as the teaching value.

  Thus, by setting a highly accurate teaching value at the teaching stage, the deviation from the setting value in the confirmation at the time of flaw detection (step S210) can be reduced in advance, and flaw detection is performed more efficiently in a short time. It becomes possible.

  Here, the relationship between the sensor and the subject will be described with reference to FIGS.

  12 to 15 are explanatory diagrams of the relationship between the sensor and the subject in the ultrasonic flaw detection method.

  Hereinafter, in the case where ultrasonic waves are transmitted to a structure that is a subject via an intermediate medium, a change in the positional relationship between the ultrasonic waves and the subject in the case of the water immersion method will be described as an example.

  As shown in FIG. 12, a case is considered where the surface 210 of the subject 101 has a curved surface, and the probe is scanned so that the ultrasonic incident point changes from point A to point B. At point A, the probe 202A is installed at an angle θA with respect to the normal line orthogonal to the tangent line 204A of the ultrasonic incident point 203A. By arranging in this way, the ultrasonic wave 208A enters the incident point 203A on the subject at an angle θA, and is refracted at an angle θA ′ on the surface of the subject, whereby the oblique ultrasonic wave 209A propagating in the steel material is generated. can get.

  FIG. 12 shows an example of probe scanning not considering flaw detection conditions. When the ultrasonic probe is simply translated from the position 202A and scanned to the position 202B, the ultrasonic wave 208B is incident at an angle θB with respect to the normal perpendicular to the tangent line 204B with respect to the incident point 203B. The light is refracted at an angle θB ′ and propagates as an oblique supersonic wave 209B.

  At this time, the refraction angle θA ′ with respect to the subject at point A and the refraction angle θB ′ with respect to the subject at point B are different. It is not possible to confirm whether or not there has been a deviation in angle during ultrasonic flaw detection, and if it is evaluated that there has been no deviation, an accurate evaluation cannot be performed because the actual refraction angle is different. For this reason, in general, in an ultrasonic examination, it is required to inspect an object (or a reflection source inside the object) while maintaining the same angle (for example, 45 °), and a change in refraction angle is required. It is necessary to move the probe so that there is no.

Comparing the propagation speed of longitudinal ultrasonic waves for the intermediate medium (water) used in the water immersion method and the subject (for example, steel), the sound velocity of water V1 = 1500 m / s and the sound velocity of steel V2 = 6000 m / s. Quad sound speed is different. For this reason, the relationship of the following formula | equation (2) is materialized by the incident angle (theta) 1 from water, and the refraction angle (theta) 2 to steel materials from Snell's law.

sin θ2 = sin θ1 × (V2 / V1) (2)

That is, the greater the sound speed ratio (V2 / V1), the greater the angular change due to refraction. For example, if the incident angle is deviated by a small angle Δθ from θ1 = 0 °, when evaluating the ultrasonic flaw detection result, if the deviation amount cannot be grasped, the sound speed ratio V2 / Since V1 = 4, the refraction angle in the steel material has a large deviation of 4Δθ.

  Further, the distance from the point 207A to the point 203A and the distance from the point 207B to the point 203B are also different with respect to the distance (water distance) between the point where the ultrasonic wave is transmitted from the probe and the ultrasonic incident point on the subject. .

  Therefore, when the ultrasonic wave reception waveforms at the points A and B are compared, as shown in FIGS. 13A and 13B, the signals (301A and 301B) from the subject surface and the signals (302A and 302A) from the inside of the subject are obtained. 302B), the reception time is different by the time difference Δt. In ultrasonic inspection, the position and properties of the reflection source are specified according to the time of the received signal. Therefore, the probe position is moved so that the reception time of the signal from the reflection source does not vary depending on the probe position. There is a need.

With respect to the time lag of the received signal, if the propagation distance in water is D1 and the propagation distance in steel is D2, the one-way propagation time T is expressed by Equation (3).

T = (D1 / V1) + (D2 / V2) (3)

Here, since the ultrasonic flaw detector generally uses the sound velocity V2 of the subject and displays the propagation time converted into the propagation distance, the propagation time of the equation (2) is expressed as the propagation in the steel material. When converted into the distance W, it can be expressed as equation (4).

W = D1 × (V2 / V1) + D2 (4)

Accordingly, if the propagation distance D1 in water is deviated by ΔD, the sound velocity ratio V2 / V1 = 4. Therefore, when the ultrasonic wave flaw detection cannot be performed, the one-way propagation displayed on the ultrasonic flaw detector The path W is displayed as a large deviation of 4ΔD, which causes an error in the evaluation result.

  In this way, in ultrasonic inspection through a medium such as the water immersion method, it is possible to correctly set the angle of the probe position and the distance to the subject, and to grasp the actual positional relationship at the time of flaw detection, Necessary for accurate evaluation.

  Next, an example of probe scanning in consideration of flaw detection conditions will be described with reference to FIG. When scanning the ultrasonic probe from the position 202A to the position 402B, the ultrasonic wave 406B is incident at an angle 406B equal to the angle θB with respect to the normal line orthogonal to the tangent line 204B with respect to the incident point 203B. If the angle of the probe is set, it is refracted at an angle 410B equal to the angle 210A on the surface of the subject and propagates as an oblique supersonic wave 409B.

  Accordingly, the angle between the probe and the subject surface is set to be constant, and the probe is moved in the vertical direction 408B of the probe surface at the probe position 402B, as shown in FIG. Thus, the probe surface 201 can be brought into contact with the subject surface 201 by moving the probe on which the acoustic lens is installed to the position 407C while maintaining the refraction angle with respect to the subject.

  Until the probe contacts the subject, the distance to the subject surface can be measured from the propagation time 303 of the reflected wave from the subject surface.

If the propagation distance in the acoustic lens is D0 (sonic velocity V0), the propagation distance in water is D1, and the propagation distance in steel is D2, the one-way propagation time T can be written as in the following equation (5).

T = (D0 / V0) + (D1 / V1) + (D2 / V2) (5)

Since the ultrasonic flaw detector generally uses the sound velocity V2 of the subject to display the propagation time converted into the propagation distance, the propagation time of the equation (5) is set to the propagation distance W in the steel material. When converted, it can be written as equation (6).

W = D0 × (V2 / V0) + D1 × (V2 / V1) + D2 (6)

In the contact state, only the propagation distance W0 (formula (7)) by the acoustic lens is present, and therefore the distance to the contact can be evaluated based on the difference in distance from the propagation distance W to W0.

W0 = D0 × (V2 / V0) (7)

At this time, the propagation distance may be converted by the sound velocity of water as an intermediate medium, or the acoustic lens propagation distance W0 may be subtracted from the propagation distance W in advance for evaluation.

Next, a case where an ultrasonic flaw detection method is performed by a phased array method through an intermediate medium such as water with an array probe provided with an acoustic lens will be described with reference to FIGS.
FIGS. 16 to 17 are explanatory diagrams when the ultrasonic flaw detection method is performed by the phased array method through an intermediate medium such as water with an array probe in which an acoustic lens is installed.

  In the middle of the process until the array probe is brought into contact with the subject surface, the pitch lens and the subject surface are not in contact. Therefore, when the positional relationship between the array probe and the surface of the subject is not properly set, that is, when the array probe is brought into contact with the subject without facing it, the subject and the array probe come into contact with each other. Even in such a case, a state of not facing directly is maintained.

  For example, it is assumed that the array probes 100A and 100B and the subject 101 face each other at a certain probe position. FIG. 16 is a schematic diagram of an array probe and a subject when facing each other. Here, the term “facing” means, for example, that the lower surface 706 of the array probe and the tangent plane 701 of the subject directly below the center 702 of the lower surface of the array probe are parallel. In this case, an ultrasonic wave is transmitted from the transmission point 702 of the array probe 101A, refracted into the subject from the incident point position 703 on the subject, and the ultrasonic wave propagates in the direction of the point 704 in the subject. If the reflection source is located at the position 704, the ultrasonic wave propagates in the opposite direction to the transmission, that is, the reflection source position 704, the incident point position 703, and the transmission point (= reception point) 702, and the array probe. Received by the child 100B.

  The intensity of the received signal is characterized by black and white or color, and the received signal is displayed on the propagation path. In addition, since the ultrasonic wave transmitted from the array probe can change the transmission and reception angles according to the delay pattern, the obtained image is a fan-shaped region 705A inside the subject, and the received waveform The intensity map is displayed in black and white or color.

  Here, it is assumed that the array probe position is moved to another point by AUT, and the facing relationship cannot be maintained. The positional relationship between the array probe and the subject at this time is shown in FIG. When the array probe and the subject are not in direct alignment, the ultrasonic waves transmitted from the transmission points 802 of the array probes 100A and 100B are incident on the incident point position 803 on the subject and refracted. Then, it propagates toward the point 804 in the subject. At this time, when the positional relationship between the array probe and the subject is different from one point (FIG. 16) to another point (FIG. 17), the angles of the ultrasonic waves transmitted from the array probe are the same. However, since the incident angle of the ultrasonic wave with respect to the subject is different, the refraction angle is different. In practice, an area to be displayed as a cross-sectional image such as the area 805 is inspected. However, when a change in the positional relationship is not assumed, the refraction angle of the ultrasonic wave to the subject is assumed to be a right-to-face display. Will be displayed. Thus, if the positional relationship between the array probe and the subject is not controlled due to the shift of the cross-sectional view, an accurate flaw detection result (cross-sectional view) may not be obtained.

  Thus, in order to obtain a more accurate and reliable flaw detection result, among the positional relationship between the array probe and the subject, in particular, the ultrasonic incident position (the array probe and the subject surface) on the subject. It is necessary to adjust the angle between the two.

  In order to perform mutual position adjustment between the array probe and the subject surface, position adjustment is required in a state where the acoustic lens 100C and the subject surface 601 are not in contact with each other. The reason for this is to avoid interference between the inspection device such as the probe and the inspection object in consideration of the possibility that the accurate positional relationship of the object cannot be grasped when inspecting the object with the remote scanning mechanism. In addition, the inspection apparatus is installed in a positional relationship that does not sufficiently contact as an initial position.

  In the present embodiment, the mutual position adjustment between the array probe and the subject surface can be performed by teaching the shape of the subject surface as described with reference to FIG. By performing mutual positional adjustment between the array probe and the subject surface, the subject having a complicated surface shape can be detected as described with reference to FIG.

  As described above, according to the present embodiment, the array probe including the acoustic lens is set so that the two element groups constituting the array probe are dedicated to transmission and reception, respectively. By reducing noise due to multiple reflections in the inside, a reflected wave from the inside of the subject can be received, and flaw detection can be performed at the sound speed of the subject.

  Further, in addition to the flaw detection based on the sound velocity of the subject that is normally performed, the subject is divided into two element groups constituting the array probe, and at least one of the two element groups is set to be used for both transmission and reception. The reflected wave from the surface can be received, and the surface shape of the subject can be specified by performing flaw detection at the sound velocity of the medium existing between the array probe and the subject. The distance of the subject can be specified.

  Further, it is possible to set the array probe and the subject at the directly facing position according to the intensity of the signal from the subject surface.

  Therefore, in the flaw detection method based on the direct contact method in which the object and the acoustic lens are brought into contact with the array probe having the acoustic lens, the positions of both in the initial state where the array probe and the object surface are not in contact with each other. The relationship can be specified, and even if there is a deviation in the positional relationship, the distance and angle between the array probe and the subject can be specified from the flaw detection result based on the sound velocity of the medium. Therefore, the position adjustment can be performed so that the array probe is brought into contact with the surface of the subject, and an accurate flaw detection result with accurate position accuracy can be provided.

  In addition, in the teaching performed before flaw detection, an array probe is used by combining the image of the reflected wave from the surface of the subject using the sound velocity of the medium and the signal from the inside of the subject using the sound velocity of the subject. It is possible to provide more accurate teaching points with respect to the child positions, to reduce the positional deviation during flaw detection, and to provide flaw detection results with accurate position accuracy.

  In addition, if there is teaching information for automatic scanning performed prior to flaw detection in teaching performed prior to flaw detection, this information can be used to provide teaching points for the position of the array probe more accurately. In addition, it is possible to reduce the deviation of the positional relationship at the time of flaw detection, and it is possible to provide an accurate flaw detection result.

In addition, the defect image can be inspected by displaying the acoustic image based on the sound velocity of the subject, and the positional relationship between the array probe and the subject can be specified by displaying the acoustic image based on the sound velocity of the medium. The position of the array probe relative to the surface of the specimen can be adjusted, and the measurement position accuracy of the reflection source position and the accuracy of the defect dimension measurement are improved in the acoustic image of the flaw detection result obtained by the sound velocity of the subject performed after contacting the surface of the specimen. .

100, 100A, 100B ... Array probe 100C ... Acoustic lens 101 ... Subject 102 ... Remote scanning mechanism 104 ... Ultrasonic transceiver 105 ... Ultrasonic image display means

Claims (2)

An ultrasonic wave transmitted from an ultrasonic probe comprising an array probe to an object via an acoustic lens and a medium and scanning the ultrasonic probe using a remote scanning mechanism A flaw detection method,
Using an ultrasonic transmitter / receiver, teaching the probe position to enable scanning to keep the ultrasonic probe at a predetermined distance and angle with respect to the subject,
The teaching transmits ultrasonic waves to the medium, receives a reflected wave from the surface of the subject as a first reception signal, and uses the sound speed of the medium to detect a flaw detection image based on the first reception signal. Recording and displaying as a first acoustic image so as to obtain the surface profile of the subject,
Based on the surface profile of the subject obtained by the teaching, the ultrasonic probe with respect to the subject is maintained at a predetermined distance and angle by a drive control device, and the ultrasonic transmitting / receiving device is used. Conducting a test of the subject ,
The inspection of the subject transmits ultrasonic waves to the inside of the subject through the medium, receives a reflected wave from the inside of the subject as a second reception signal, and uses the second reception signal. A flaw detection image is recorded and displayed as a second acoustic image using the sound velocity of the subject, and simultaneously or switching, a reflected wave from the surface of the subject is received as a first received signal, An ultrasonic flaw detection method comprising displaying a flaw detection image based on the first reception signal as a first acoustic image using a sound speed of the medium . The ultrasonic flaw detection method according to claim 1,
The array probe comprises first and second array probes comprising two element groups;
Wherein at least one of the first and second arrays probe and both transmission and reception, the received reflected waves from the surface of the object as a first reception signal, and displayed as the first acoustic image,
One of the first and second array search unit, sets the one of the one for transmission and the other for the reception, receives the reflected waves from the inside of the subject as a second reception signal, wherein An ultrasonic flaw detection method characterized by displaying as a second acoustic image.

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