JP7091191B2 - Ultrasonic flaw detector and ultrasonic flaw detector method - Google Patents

Description

Embodiments of the present invention relate to an ultrasonic flaw detector and an ultrasonic flaw detector.

Ultrasonic testing (UT) is a technology that can confirm the soundness of structural materials by exploring defects on the surface and inside of structural materials in a non-destructive manner, and is an indispensable inspection technology in various fields. It has become. Phased array ultrasonic flaw detection test that can form an arbitrary waveform by arranging piezoelectric elements as small ultrasonic elements for transmitting and receiving ultrasonic waves and transmitting ultrasonic waves by shifting the timing (delay time) for each piezoelectric element. (PAUT: Phased Array UT) is also widely used in industrial applications. Compared to monocular probes that can emit ultrasonic waves only at a predetermined angle, phased array ultrasonic flaw detection technology can detect a wide range with a single flaw detection, detect flaws at multiple angles, and handle complex shapes. There is a possibility that it can be done. For this reason, the phased array ultrasonic flaw detection technique is very attractive in that it can reduce the work man-hours during inspection.

Japanese Patent No. 5797375

In recent years, large-scale power plants such as nuclear power plants and thermal power plants and social infrastructure equipment have become older, and the parts to be inspected and the types of defects to be detected have been expanded compared to the past.

For defects with continuous long interfaces such as cracks and wall thinning that have been sought so far, it is common to use time information of ultrasonic waveforms for position identification and shape identification. On the other hand, when measuring volume defects close to a sphere such as fusion defects and blow holes caused by so-called welding and casting by ultrasonic waves, time information is often used for position identification, and ultrasonic echo intensity is often used for shape identification.

In the determination using the time information, the position can be uniquely determined by referring to the speed of sound in the object to be inspected. On the other hand, in the determination using the intensity, the defect shape is determined by comparing it with a comparison target such as a signal intensity database according to the defect diameter.

However, since the shape of the volume defect is not uniform, there may be a discrepancy between the defect shape determined by the database and the actual defect shape. Further, when a plurality of small defects exist as a group, it is extremely difficult to distinguish between a large single defect and a defect group.

For example, a device for detecting group defects occurring on a joint surface in the manufacture of electrosewn steel pipes is known, but this is a configuration on the premise that group defects occur at the interface to the last, and is a large unit. It is not a technique for distinguishing between defects and group defects.

Therefore, an embodiment of the present invention aims to perform a highly accurate flaw detection inspection such as discriminating between a single defect and a group defect in ultrasonic flaw detection.

In order to achieve the above object, the ultrasonic flaw detector according to the present embodiment is a plurality of ultrasonic elements arranged in a predetermined direction that transmit ultrasonic waves to an inspection target and receive ultrasonic waves reflected by the inspection target. The ultrasonic array probe having the above and the plurality of the ultrasonic elements constituting the driven element group are selected, and the delay time for shifting the timing of transmission / reception of ultrasonic waves by each of the selected ultrasonic elements is calculated. A calculation unit for determining the existence status of defects inherent in the inspection target based on the ultrasonic waves transmitted and received based on the calculated delay time is provided, and the calculation unit is provided with a predetermined unit in the inspection target. The ultrasonic beam is configured to be able to switch between a first condition such that the mode of the ultrasonic beam to the position is the first mode and a second condition such that the mode of the ultrasonic beam is different from the first mode. The first aspect and the second aspect are different in beam diameter, and the calculation unit further includes a beam diameter setting switching unit for switching the beam diameter .

Further, in the ultrasonic flaw detector method according to the present embodiment, each of the plurality of ultrasonic elements constituting the driven element group of the ultrasonic array probe transmits ultrasonic waves to the inspection target, and the plurality of ultrasonic elements are used. The first aspect is an ultrasonic beam in which the ultrasonic receiving / transmitting step for receiving the reflected wave from the inspection target and the setting switching unit are formed by ultrasonic waves transmitted from each of the plurality of ultrasonic elements. The setting step for setting the first condition and the second condition, which is a second aspect different from the first aspect, and the defect discriminating unit are the first reflected signal of the ultrasonic beam of the first aspect and the said. The second aspect comprises a defect determination step of determining a defect based on the second reflected signal of the ultrasonic beam, and the first aspect and the second aspect of the ultrasonic beam are of the ultrasonic beam. It is characterized by further having a beam diameter switching step in which the beam diameter is different and the beam diameter is changed .

According to the embodiment of the present invention, high-precision inspection is possible in ultrasonic flaw detection.

It is a block diagram which shows the structure of the ultrasonic flaw detector which concerns on embodiment. It is a flow figure which shows the procedure of the ultrasonic flaw detection method which concerns on embodiment. The state of each transmission and reception of ultrasonic waves in the ultrasonic flaw detection method according to the embodiment is shown, (a) is a system diagram, and (b) is a reception signal in each ultrasonic element when transmitted from the first ultrasonic element. It is a figure which shows. The state of each transmission and reception of ultrasonic waves in the ultrasonic flaw detection method according to the embodiment is shown, (a) is a system diagram, and (b) is a reception signal in each ultrasonic element when transmitted from the second ultrasonic element. It is a figure which shows. The state of each transmission and reception of ultrasonic waves in the ultrasonic flaw detection method according to the embodiment is shown, (a) is a system diagram, and (b) is a reception signal in each ultrasonic element when transmitted from the Nth ultrasonic element. It is a figure which shows. It is a conceptual block diagram explaining the delay time calculation in the ultrasonic flaw detection method which concerns on embodiment. It is a 1st graph explaining the estimated delay time calculation in the ultrasonic flaw detection method which concerns on embodiment. It is a 2nd graph explaining the estimated delay time calculation in the ultrasonic flaw detection method which concerns on embodiment. It is a figure explaining the arrival time calculation in the ultrasonic flaw detection method which concerns on embodiment, (a) is a system diagram, (b) is each ultrasonic wave when it is transmitted from the 1st to 3rd ultrasonic element. It is a figure which shows the received signal in an element. It is a figure which shows the received signal in each ultrasonic element which considered the delay time in the ultrasonic flaw detection method which concerns on embodiment. It is a figure which shows the synthetic waveform obtained by the ultrasonic flaw detection method which concerns on embodiment. It is a conceptual cross-sectional view explaining the influence of the focal depth in the ultrasonic flaw detection method which concerns on embodiment, and shows the case where the focal depth is larger than the measured coordinate depth. It is a conceptual cross-sectional view explaining the influence of the focal depth in the ultrasonic flaw detection method which concerns on embodiment, and shows the case where the focal depth is equal to the measured coordinate depth. It is a conceptual cross-sectional view explaining the influence of the focal depth in the ultrasonic flaw detection method which concerns on embodiment, and shows the case where the focal depth is smaller than the measured coordinate depth. It is a conceptual sectional view explaining the influence of the number of driven elements of a driven element group in the ultrasonic flaw detection method which concerns on embodiment, and shows the case where the number of driven elements of a driven element group is eight. .. It is a conceptual sectional view explaining the influence of the number of driven elements of a driven element group in the ultrasonic flaw detection method which concerns on embodiment, and shows the case where the number of driven elements of a driven element group is four. .. In the ultrasonic flaw detection method according to the embodiment, it is a conceptual cross-sectional view explaining the difference between two beam diameters, and shows the case where a single defect is present and the beam diameter is small. In the ultrasonic flaw detection method according to the embodiment, it is a conceptual cross-sectional view explaining the difference between two beam diameters, and shows the case where a single defect is present and the beam diameter is large. It is a conceptual cross-sectional view explaining the difference between two beam diameters in the ultrasonic flaw detection method according to the embodiment, and the number of driven elements in the driven element group is 8 even when two small defects are present. The case of pieces is shown. It is a conceptual cross-sectional view explaining the difference between two beam diameters in the ultrasonic flaw detection method according to the embodiment, and the number of driven elements in the driven element group is 4 even when two small defects are present. The case of pieces is shown. It is a conceptual cross-sectional view explaining the difference between two beam diameters in the ultrasonic flaw detection method which concerns on embodiment, and it is the case where there is one small defect, and the number of driven elements of a driven element group is eight. Show the case. It is a conceptual cross-sectional view explaining the difference between two beam diameters in the ultrasonic flaw detection method which concerns on embodiment, and it is the case where there is one small defect, and the number of driven elements of a driven element group is eight. Show the case. It is a graph which shows the change of the normalized signal intensity when the beam diameter is changed in the ultrasonic flaw detection method which concerns on embodiment. In the ultrasonic flaw detection method according to the embodiment, it is a conceptual cross-sectional view explaining the difference depending on the measurement position at the first beam diameter when two small defects are present, and is a conceptual cross-sectional view of the first measurement position. Show the case. In the ultrasonic flaw detection method according to the embodiment, it is a conceptual cross-sectional view explaining the difference depending on the measurement position at the first beam diameter when two small defects are present, and is the second measurement position. Show the case. In the ultrasonic flaw detection method according to the embodiment, it is a conceptual cross-sectional view explaining the difference depending on the measurement position at the second beam diameter when two small defects are present, and is a conceptual cross-sectional view of the first measurement position. Show the case. In the ultrasonic flaw detection method according to the embodiment, it is a conceptual cross-sectional view explaining the difference depending on the measurement position at the second beam diameter when two small defects are present, and is a conceptual cross-sectional view of the second measurement position. Show the case. It is a graph which shows the change of the normalized signal strength with respect to the change of the measurement coordinates when two small defects are present in the ultrasonic flaw detection method which concerns on embodiment. It is a graph which shows the change of the normalized signal strength with respect to the change of the measurement coordinates when one big defect exists in the ultrasonic flaw detection method which concerns on embodiment.

Hereinafter, the ultrasonic flaw detector and the ultrasonic flaw detector according to the embodiment of the present invention will be described with reference to the drawings. Here, common reference numerals are given to parts that are the same as or similar to each other, and the description of superimposition will be omitted.

FIG. 1 is a block diagram showing a configuration of an ultrasonic flaw detector according to an embodiment. Further, FIG. 2 is a flow diagram showing the procedure of the ultrasonic flaw detection method according to the embodiment.

The ultrasonic flaw detector 100 non-destructively detects the defect 2 inherent in the inspection target 1 by ultrasonic waves. As shown in FIG. 1, the ultrasonic flaw detector 100 includes a test board 110, an ultrasonic array probe 10, and a moving drive unit 15 for driving the ultrasonic array probe 10.

The ultrasonic array probe 10 has a plurality of ultrasonic elements 11 and a holding portion 12 for holding them. The ultrasonic element 11 is a piezoelectric element made of ceramics or a composite material that can transmit and receive ultrasonic waves due to its piezoelectric effect, a piezoelectric element made of a polymer film, or an element that can transmit and receive ultrasonic waves other than that. Each ultrasonic element 11 may have a damping member for damping ultrasonic waves and a front plate attached to the front surface, for example, generally called an ultrasonic probe.

In the ultrasonic array probe 10, N (N: natural number) ultrasonic elements 11 that transmit ultrasonic waves to the inspection target 1 and receive the ultrasonic waves reflected and scattered by the inspection target 1 and the defect 2 are positioned at predetermined positions. It is arranged in.

In the following, in the ultrasonic array probe 10, when the ultrasonic element 11 is arranged at a predetermined position, it is generally called a linear array probe, that is, the ultrasonic element 11 is one-dimensional in the first direction. The case where they are arranged in is shown as an example, but the present invention is not limited to this. The ultrasonic array probe 10 may be an array probe having another type of configuration, as long as it is arranged at a predetermined position. Alternatively, so-called tandem flaw detection may be performed in which a plurality of types are used in combination.

Other types include a 1.5-dimensional array probe in which the ultrasonic element is divided into non-uniform sizes in the depth direction of the linear array probe (the second method perpendicular to the first direction), and the ultrasonic element 11. Matrix array probes two-dimensionally arranged in different first and second directions, and ultrasonic elements 11 having a ring shape in the first direction and a radial direction in the second direction are arranged concentrically. There are a ring array probe, a split type ring array probe in which a plurality of ultrasonic elements 11 of the ring array probe are divided in the circumferential direction, and the like. Further, a non-uniform array probe in which the ultrasonic element 11 is non-uniformly arranged, an arc-shaped array probe in which the first direction is arcuate and the ultrasonic element 11 is arranged at the circumferential position thereof, and a super on the surface of the spherical surface. Examples thereof include a spherical array probe in which the ultrasonic element 11 is arranged.

The ultrasonic array probe 10 includes those that can be used regardless of the air environment or the liquid environment by using caulking or packing.

The mobile drive unit 15 moves and drives the ultrasonic array probe 10 around the inspection target 1, for example, while gripping the holding unit 12 or accommodating a part of the holding unit 12.

A wedge (not shown) may be used to inject ultrasonic waves into the inspection target 1 at a high directivity angle. For the wedge, an isotropic material such as acrylic, polyimide, gel, or other polymer, which can propagate ultrasonic waves and whose acoustic impedance can be grasped, is used. Further, the wedge may be made of a material having an acoustic impedance close to or the same as that of the front plate. Alternatively, the wedge may be made of a material having an acoustic impedance close to or the same as that of the inspection target 1. Further, a composite material may be used in which the acoustic impedance is gradually or gradually changed.

Furthermore, it has a mechanism to reduce multiple reflections by arranging damping materials inside and outside the wedge, providing a mountain-shaped wave-dissipating member, so that the multiple reflection waves in the wedge do not affect the flaw detection result. It may be that. In the following description, the description and illustration of the wedge when the ultrasonic wave is incident from the ultrasonic array probe 10 to the inspection target 1 are omitted.

The acoustic contact medium 5 acoustically couples, that is, almost acoustically, between the ultrasonic array probe 10 and the wedge, between the wedge and the inspection target 1, or between the ultrasonic array probe 10 and the inspection target 1. The entire amount can be passed. The acoustic contact medium 5 is, for example, water, glycerin, machine oil, castor oil, acrylic, polystyrene, gel, or the like, but other media can be used as long as they can propagate ultrasonic waves. In the following description, the description of the acoustic contact medium 5 may be omitted when the ultrasonic waves are incident on the inspection target 1 from the ultrasonic array probe 10.

The test board 110 includes a transmission / reception unit 20, a calculation unit 30, a storage unit 40, a control unit 50, a display unit 60, and an input unit 70. The test board 110 includes a device having a function of performing general-purpose calculation and data communication such as a so-called PC (Personal Computer), and includes each mounted part or can be connected by a communication cable. be.

The transmitting / receiving unit 20 includes a potential difference applying unit 21, a switching unit 22, and an AD conversion unit 23.

The potential difference application unit 21 can apply a potential difference that causes vibration to the ultrasonic element 11. The switching unit 22 makes the selected ultrasonic element 11 and the potential difference applying unit 21 conductive and non-conducting, that is, a state in which the potential difference is applied to the ultrasonic element 11 and a state in which the potential difference is not applied. Make a switch.

The potential difference applying unit 21 applies a voltage having an arbitrary waveform to the ultrasonic element 11 which has been brought into a conductive state by the switching unit 22. The waveform of the applied voltage includes a sine wave, a serrated wave, a square wave, a spike pulse, and the like, and may be a so-called bipolar waveform having both positive and negative pole values, or a unipolar waveform having either positive or negative polarity. Moreover, either positive or negative offset may be added. Further, the waveform may be a single pulse, a burst, a continuous wave, or the like, and the application time or the number of repeated waves may be increased or decreased.

Hereinafter, the ultrasonic element 11 which is in a conductive state and is applied with a voltage is referred to as a driven element, and a plurality of ultrasonic elements 11 driven so as to form the same focal point are referred to as a driven element group. It shall be called. It should be noted that the ultrasonic elements 11 constituting a certain driven element group may be driven at the same time as each other with a delay time described later and may be focused. Alternatively, if they are actually driven at the same time, ultrasonic waves are individually transmitted to the plurality of ultrasonic elements 11 that connect a predetermined focus, and the reflected waves are stored in the signal processing information storage unit 41 as data. As will be described later, these plurality of ultrasonic element 11s when the reflected wave data is synthesized in consideration of the respective delay times are also referred to as a driven element group.

The reflected wave received by the ultrasonic element 11 is an analog signal, that is, a signal continuous with time. Therefore, the AD conversion unit 23 converts the analog signal into a digital signal, and enables the arithmetic unit 30 to perform digital processing.

The input unit 70 accepts an input from the outside. The inputs include information on the attributes of the inspection target 1 such as the shape, dimensions, and materials of the inspection target 1, and information on the state of the inspection target 1 such as the temperature of the inspection target 1. Further, the selection instruction of the ultrasonic element 11 used for transmission and the ultrasonic element 11 used for reception is also input. Further, although the details will be described later, an external input of characteristic data grasped in advance by using an object different from the inspection target 1 in advance is accepted.

The display unit 60 plans the information required for the inspector and the like based on the progress order, including the image of the inspection result, based on the information from the transmission / reception unit 20, the calculation unit 30, and the storage unit 40. Display as requested or as requested. The display unit 60 may be a liquid crystal display device, a projector, a cathode ray tube, or the like, as long as it can display digital data. Further, the display unit 60 may have a user interface function of generating an alarm by sound or light emission according to a set condition or inputting an operation as a touch panel.

The storage unit 40 has a signal processing information storage unit 41 and a dependent characteristic storage unit 42.

The signal processing information storage unit 41 is the information of the reflected wave after the AD conversion unit 23 of the transmission / reception unit 20 AD-converts the reflected wave received by the ultrasonic array probe 10, that is, the digital data of the reflected wave, and the calculation unit 30. The result of arithmetic processing in each element is saved in.

The dependent characteristic storage unit 42 has the intensity of the reflected wave with respect to the beam diameter d at the measurement coordinates P (FIG. 15) when a plurality of defects 2 are present at close distances to each other or when a single defect is present. Each of the dependent characteristics of the above is grasped in advance using an object different from the inspection target 1 and converted into data, which is received and stored via the input unit 70. Further, as described below, the dependent characteristic of the intensity of the reflected wave with respect to the beam diameter d or the measurement coordinate P obtained as a result of the flaw detection performed on the inspection target 1 is stored.

Here, the ultrasonic beam is a band-shaped or rod-shaped region formed by overlapping ultrasonic waves transmitted from a plurality of ultrasonic elements 11, that is, each ultrasonic wave is synthesized by a method described later. It shall refer to a spatial set of things. Further, the beam diameter refers to a typical width of a cross section of the ultrasonic beam at each position in the traveling direction of the ultrasonic beam. The typical width is, for example, a diameter if it is circular, a major axis or minor axis if it is elliptical, and a long side or short edge length if it is almost rectangular.

The ultrasonic beam does not have to be actually realized. That is, when each reflected wave by ultrasonic waves individually transmitted from each ultrasonic element 11 forming the driven element group is collected as reflected wave data in advance, the delay time, that is, each ultrasonic element It may be an ultrasonic beam virtually obtained by calculating from the relationship between 11 and the measurement coordinate P and synthesizing in consideration of the delay time assigned to each ultrasonic element 11.

The control unit 50 monitors the progress state of each component in the test board 110 so that each process in each component in the test board 110 can proceed while maintaining consistency as a whole, and the timing of each process. Etc. are controlled.

As shown in FIG. 2, in the ultrasonic flaw detection method, first, ultrasonic waves are individually emitted from the ultrasonic elements 11 of the driven element group, and the signal processing information storage unit 41 stores the reflected wave data. (Step S01).

3 to 5 are diagrams showing the state of each transmission / reception of ultrasonic waves in the ultrasonic flaw detection method according to the present embodiment, (a) is a system diagram, and (b) is a diagram showing a reception signal in each ultrasonic element. 3, FIG. 3 shows a case where the first ultrasonic wave element, FIG. 4 shows the case where the second ultrasonic wave element is transmitted, and FIG. 5 shows the case where the sound wave is transmitted from the Nth ultrasonic wave element. The ultrasonic flaw detector 100 is installed with the direction in which the ultrasonic elements 11 are arranged in the x direction as the longitudinal direction. From each ultrasonic element 11, ultrasonic waves are transmitted in the depth direction (z direction) of the inspection target 1, and the transmitted ultrasonic waves spread with time.

In the ultrasonic flaw detector 100, in this case, a set of three ultrasonic elements 11 is, for example, first (1,2,3), then (2,3,4), and then (3). , 4, 5), ..., (N-2, N-1, N) are sequentially shifted by one to scan in the longitudinal direction (x direction).

In each (b), the display of Uf (i, j) is the waveform of the reflected wave transmitted from the i-th ultrasonic element 11 and received by the j-th ultrasonic element 11. Represent. Further, in the following, Uf (i, j) may be expressed as Ufi, j.

In the above ultrasonic transmission / reception, one ultrasonic element transmits ultrasonic waves, a plurality of ultrasonic elements receive ultrasonic waves, and each ultrasonic element is independent and has an ultrasonic waveform Uf (i, j). ). When an ultrasonic array probe composed of N ultrasonic elements is used, the ultrasonic waveform of a maximum N × N pattern is recorded by changing the transmitting element. Here, it is also possible to have a plurality of elements used for transmission while maintaining the function of holding the waveform independently for each piezoelectric element. In this case, the ultrasonic waves can be made into a plane wave, focused, diffused, or the like over a delay time.

The calculation unit 30 determines the timing of transmission of ultrasonic waves from the ultrasonic element 11, and creates composite image data based on the received waveform. The calculation unit 30 includes a measurement coordinate setting switching unit 31, a delay time calculation unit 32, a synthesis calculation unit 33, a flaw detection image drawing unit 34, a beam diameter setting switching unit 35, a standardized signal intensity calculation unit 36, and a defect determination unit 37. Have.

The measurement coordinate setting switching unit 31 and the beam diameter setting switching unit 35 form a setting switching unit. The setting switching unit switches the mode of the ultrasonic beam described later. As an embodiment of the ultrasonic beam, for example, there are measurement coordinates set and changed by the measurement coordinate setting switching unit 31, or a beam diameter set and changed by the beam diameter setting switching unit 35.

The measurement coordinate setting switching unit 31 sets or changes the coordinate position of the measurement coordinate P as the position of interest in the inspection target 1. The measured coordinates P may be, for example, in the form of coordinates in the xz plane or coordinates in a three-dimensional space, or after being divided into meshes, all of them are sequentially assigned consistent numbers and expressed one-dimensionally. It may be a thing.

As shown in FIG. 2, in the ultrasonic flaw detection method, the measurement coordinate setting switching unit 31 of the setting switching units next selects the measurement coordinate P (step S02).

The delay time calculation unit 32 calculates the delay time for shifting the transmission / reception timing, which is necessary for the ultrasonic waves transmitted from the respective ultrasonic elements 11 to be focused on the focal point 3 (FIG. 3). do.

As shown in FIG. 2, in the ultrasonic flaw detection method, the delay time calculation unit 32 next calculates the delay time (step S03). FIG. 6 is a conceptual configuration diagram illustrating a delay time operation. FIG. 7 is a first graph illustrating the estimated delay time operation, and FIG. 8 is a second graph.

The delay time is calculated from the positional relationship between the center C (FIG. 12) and the focal point F (FIG. 6) of the driven element group. Here, the focal point F is a coordinate that reaches a certain depth from the center C of the driven element group for forming the composite waveform M through the path of the incident angle α and the refraction angle β. By dividing the linear distance from the center C of the driven element group to the focal point F by the speed of sound of the object to be inspected, the ultrasonic waves emitted from each ultrasonic element as shown in FIG. 7 propagate until the focal point F is reached. You get each time. As shown in FIG. 8, the propagation time of all the ultrasonic elements 11 is subtracted by the longest propagation time, and the positive / negative inverted time is the delay time added to each ultrasonic element 11.

For example, in the case of actually transmitting ultrasonic waves to converge on the focal point, if the ultrasonic waves are transmitted from each ultrasonic element 11 with a delay by the delay time of the transmitting side assigned to each, the result is predetermined. Will converge to the focus of. That is, the ultrasonic waves transmitted from each ultrasonic element 11 constituting the driven element group in consideration of the delay time on the transmitting side pass through the focal point at the same timing.

When the acoustic contact medium 5 is provided between the ultrasonic array probe 10 and the inspection target 1, the point at which the ultrasonic wave is incident on the inspection target 1 from each ultrasonic element 11 is calculated using Snell's law, and the acoustic contact medium 5 is provided. Using the sound waves of 5 and the sound wave of the inspection target 1, the propagation time required for each propagation is calculated, and then the delay time is calculated.

The delay time is calculated on both the transmit and receive paths. The surface shape of the inspection target 1 used at this time is not limited to a general flat surface or an inclined flat surface, and even if there is a curvature or uneven portion, geometric calculation can be performed in consideration of the curvature or uneven portion. This is possible by reflecting the angle information (tangential angle) of the point on the surface on which the ultrasonic wave is incident when calculating the incident point using Snell's law. The surface shape of the inspection target 1 may be calculated using the propagation time of the ultrasonic wave emitted from the ultrasonic array probe 10, or shape data such as an existing drawing may be read. Further, a means for measuring the surface shape of the inspection target 1 such as a camera or a laser range finder may be attached to the ultrasonic array probe 10 or separately provided near the ultrasonic array probe 10.

The synthesis calculation unit 33 shifts the received signal obtained by each of the received ultrasonic elements 11 in the time axis direction by the delay time, and synthesizes the signals of the shifted ultrasonic elements 11 at the same time. A synthetic waveform M is obtained. The specific contents will be described below.

9A and 9B are diagrams for explaining the arrival time calculation in the ultrasonic flaw detection method according to the embodiment, in which FIG. 9A is a body diagram and FIG. 9B is a case where the first to third ultrasonic elements are used for transmission. It is a figure which shows the received signal in each ultrasonic element of. As shown in FIG. 9, ultrasonic waves are sequentially transmitted from each of the first to third ultrasonic elements 11, and for each transmission, each of the first to third ultrasonic elements 11 receives ultrasonic waves. do. As a result, nine types of waveforms can be obtained by combining the ultrasonic element 11 on the transmitting side (i = 1 to 3) and the ultrasonic element 11 on the receiving side (j = 1 to 3).

FIG. 9B shows the basic waveforms of the ultrasonic signals Ufi and j in which the transmission timings from the ultrasonic elements 11 on the transmitting side are matched. In each waveform, the portion reflected by the defect 2 appears as a significant shape. Significant reflection occurs not only in the defect 2 but also in the discontinuous portion forming the outer shape such as the bottom surface of the inspection target 1. In the reflected wave, the portion due to such significant reflection is hereinafter referred to as a shape reflection portion.

FIG. 10 is a diagram showing a reception signal in each ultrasonic element in consideration of the delay time in the ultrasonic flaw detection method according to the embodiment. The lateral length of the rectangle filled with diagonal lines indicates the transmission delay time, that is, the time difference in the arrival time from each ultrasonic element 11 to the focal point 3 or the defect 2. The lateral length of the white rectangle indicates the reception delay time, that is, the time difference in the arrival time from the focal point 3 or the defect 2 to each ultrasonic element 11. When the delay time is taken into consideration in this way, the timings of the shape-reflected portions in the ultrasonic signals Ufi and j of the respective reflected waves are almost the same.

As described above, the synthesis calculation unit 33 shifts the ultrasonic signals Ufi, j obtained by the received ultrasonic elements 11 in the time axis direction by the delay time, and then sets the ultrasonic signals Ufi, j to 1. Combine into two composite waveforms M. Here, the synthesis is performed by, for example, addition or averaging of each signal level, but other methods may be used.

FIG. 11 is a diagram showing a synthetic waveform obtained by the ultrasonic flaw detection method according to the embodiment. In the composite waveform M obtained as a result of the composite calculation by the composite calculation unit 33, the shape reflection portion is emphasized and the existence is clarified. Further, it is possible to specify the range of the position of the reflection that caused the shape reflection portion from the occurrence time Tr of the shape reflection portion.

The flaw detection image drawing unit 34 uses the waveforms obtained at the installation positions of the ultrasonic array probe 10 for the inspection target 1 in the x direction for an image of each xz cross section, that is, depth flaw detection in the longitudinal direction. Calculate the data for the image. Imaging is a method generally called B-scan or S-scan. This image is reconstructed by the refraction angle and the refraction angle for flaw detection according to the flaw detection conditions at the time of flaw detection.

As shown in FIG. 2, in the ultrasonic flaw detection method, next, the beam diameter setting switching unit 35 of the setting switching units sets the beam diameter, which is one aspect of the ultrasonic beam (step S04).

The beam diameter setting switching unit 35 changes the beam diameter d (m, n) of the ultrasonic wave at the measurement coordinate P to change the mode of the ultrasonic beam passing through a predetermined position in the inspection target 1, according to the first aspect. And it is configured so that it can be switched to the second aspect different from the first aspect. Here, m represents the number of the beam diameter, and n represents the number of the measurement coordinate P. The number n of the measurement coordinate P (hereinafter referred to as the measurement coordinate number n) is, for example, a two-dimensional mesh division of the xz plane (two-dimensional plane), and all of them are sequentially assigned consistent numbers to 1 It is a three-dimensional expression. Instead of n, the coordinates may be represented two-dimensionally, for example, (k, l).

The beam diameter that defines the embodiment of the ultrasonic beam in a measurement is made possible by controlling the delay time and / or the number of driven elements. That is, in the beam diameter setting switching unit 35 of the calculation unit 30 in the present embodiment, the mode (beam diameter) of the ultrasonic beam to a predetermined position in the inspection target 1 is the first mode (first beam diameter). A second mode (second beam diameter) in which the mode (beam diameter) of the ultrasonic beam to a predetermined position in the inspection target 1 is different from the first mode (first beam diameter). The second condition is set by at least one of the selection of the ultrasonic element 11 constituting the driven element group and the delay time for each of the selected plurality of ultrasonic elements 11.

First, the case where the ultrasonic beam diameter is controlled by the delay time is shown with reference to FIGS. 12 to 14.

FIG. 12 is a conceptual cross-sectional view illustrating the effect of the focal depth in the ultrasonic flaw detection method according to the embodiment, and when the focal depth is larger than the measured coordinate depth, FIG. 13 shows the focal depth measured. If it is equal to the coordinate depth, and FIG. 14 shows the case where the focal depth is smaller than the measured coordinate depth.

That is, the position of the measurement coordinate P is fixed and the position of the focal point 3 is changed. The position of the focal point 3 can be adjusted by setting the delay time corresponding to this.

As shown in FIGS. 12 to 14, when the depth position of the focal point 3 is the same as the depth position of the measurement coordinate P (FIG. 13), the beam diameter d of the ultrasonic beam at the measurement coordinate P is the minimum, and the focal point is the focal point. The beam diameter d becomes large regardless of whether the depth position of 3 is deeper or shallower than this. In this way, the beam diameter d of the ultrasonic beam at the measurement coordinate P can be adjusted by changing the depth of the focal point 3 with reference to the depth of the measurement coordinate P.

Next, with reference to FIGS. 15 and 16, a case where the beam diameter d is controlled by the number of driven elements, that is, the number of ultrasonic elements 11 constituting the driven element group will be shown. FIG. 15 is a conceptual cross-sectional view illustrating the influence of the number of driven elements in the ultrasonic flaw detection method according to the embodiment, and shows a case where the number of driven elements is eight, and FIG. 16 shows a case where the number of driven elements is eight. The case where the number is four is shown.

The beam diameter d of the ultrasonic beam at the focal point 3 is obtained by the following equation (1).
d = k ・ Lf ・ λ / D ・ ・ ・ (1)
Here, Lf is the focal length, λ is the wavelength of the ultrasonic wave, and D is the effective aperture, which is proportional to the diameter of the driven element group or the number of driven elements. That is, the larger the number of driven elements, the larger the effective opening and the better the convergence. In this way, the ultrasonic beam diameter d is inversely proportional to the number of driven elements.

The ultrasonic beam shown in FIG. 15 and the ultrasonic beam shown in FIG. 16 have the focal length 3 set at the same depth, and the focal length Lf is the same for both. Therefore, a smaller beam diameter d can be obtained when the number of driven elements shown in FIG. 15 is 8 as compared with the case where the number of driven elements shown in FIG. 16 is 4.

FIG. 17 is a conceptual cross-sectional view illustrating the difference between the two beam diameters in the ultrasonic flaw detection method according to the embodiment, in the case where a large single defect is present and the beam diameter is small. , FIG. 18 shows a case where the beam diameter is large. That is, an example is shown in which the beam diameter is changed during the measurement focusing on the large single defect 2a.

In both cases where the beam diameter d of the ultrasonic beam is small (FIG. 17) and large (FIG. 18), when the large single defect 2a is larger than the cross section of the ultrasonic beam, all of the ultrasonic beams are large single defects. Since it is within the range of 2a, basically all the ultrasonic waves are reflected and scattered in the large single defect 2a.

The normalized signal intensity calculation unit 36 calculates the normalized signal intensity R (m, n) based on the reflected wave of the ultrasonic beam. Specifically, the intensity of the reflected wave of the ultrasonic beam or the intensity of the combined wave of the reflected wave reflected by the ultrasonic elements 11 constituting the driven element group is applied to the driven element group. The standardized signal strength R (m, n) divided by the number of ultrasonic elements 11 to which the ultrasonic element belongs is calculated.

When the normalized signal intensity is calculated by the normalized signal intensity calculation unit 36 (step S05), the sound pressure applied to the single defect 2a is different due to the difference in the number of driven elements. However, in each case, since all ultrasonic waves are reflected and scattered in the single defect 2a, the standard corresponding to the ultrasonic beam having the calculated beam diameter number 1 by dividing by the number of driven element groups and standardizing. It is considered that the standardized signal intensity R (1, n) corresponding to the ultrasonic beam having the beam diameter number 2 and the standardized signal intensity R (2, n) take almost the same value. In FIGS. 17 and 18, the value of the normalized signal intensity R (i, n) shows the difference between the positive peak and the negative peak, but each of them may be obtained by one of the peaks or by the integrated value of the waveform. You may.

Next, an example will be shown in which the beam diameter d is changed during the measurement focusing on the two small defects 2b (FIGS. 19 and 20). That is, FIG. 19 is a conceptual cross-sectional view illustrating the difference between the two beam diameters in the ultrasonic flaw detection method according to the embodiment, and the number of driven elements is 8 in the case where two small defects are present. A case of four is shown, and FIG. 20 shows a case where the number of driven elements is four.

In the case where the ultrasonic beam is narrowed down and the beam diameter d (1, n) of the ultrasonic beam having the beam diameter number 1 is shown in FIG. 19, most of the ultrasonic beam passes between the two small defects 2b. Therefore, the normalized signal intensity R (1, n) of the reflected wave is significantly lowered as compared with the case of the large single defect 2a shown in FIG.

On the other hand, in the beam diameter d (2, n) of the ultrasonic beam having the beam diameter number 2 in the case where the ultrasonic beam is not so narrowed down, most of the spread ultrasonic beams irradiate both small defects 2b. Therefore, a reflected wave having a certain standardized signal intensity R (2, n) can be obtained.

Next, an example will be shown in which the beam diameter d is changed during the measurement focusing on one small defect 2c (FIGS. 21 and 22). That is, FIG. 21 is a conceptual cross-sectional view illustrating the difference between the two beam diameters in the ultrasonic flaw detection method according to the embodiment, and the number of driven elements is 8 even when one small defect is present. A case of four is shown, and FIG. 22 shows a case where the number of driven elements is four.

When the beam diameter d shown in FIG. 21 is small and has substantially the same size as the small defect 2c, almost the entire amount of the ultrasonic beam is reflected. On the other hand, when the beam diameter d shown in FIG. 22 is large and larger than the small defect 2c, the ultrasonic beam reflected by the small defect 2c is only a part of the total amount of the ultrasonic beam, and the other parts pass through the small defect 2c. Resulting in. Therefore, in the case of normalization, in the case of the small defect 2c, when the beam diameter d is small, the standardized signal intensity R (1, n) of the reflected wave is larger than when the beam diameter d is large.

FIG. 23 is a graph showing the change in the normalized signal intensity when the beam diameter is changed in the ultrasonic flaw detection method according to the embodiment. The horizontal axis is the ultrasonic beam diameter d (m, n), and the vertical axis is the normalized signal intensity R (m, n). As described above, m represents the beam diameter number, and n represents the measurement coordinate P number (measurement coordinate number).

The solid line A is the case of a large single defect 2a (FIGS. 17 and 18). In the case of the small beam diameter d (m1, n) of the beam diameter number m1 shown in FIG. 17 and the case of the large beam diameter d (m2, n) of the beam diameter number m2 shown in FIG. Since the entire amount of the ultrasonic beam is reflected, the standardized signal intensities R (m1, n) and the normalized signal intensities R (m2, n) are almost equal values.

The broken line B is the case of two small defects 2b (FIG. 19 and 20). In the case of the small beam diameter d (m1, n) shown in FIG. 19, most of the ultrasonic beam passes between the two small defects 2b, so that the normalized signal intensity R (m1, n) becomes small. On the other hand, in the case of the large beam diameter d (m2, n) shown in FIG. 20, since most of the ultrasonic beam is reflected, the normalized signal intensity R (m2, n) has a small beam diameter d (m2, n). It is larger than the standardized signal strength R (m1, n) in the case of m1, n).

The dotted line G is the case of one small defect 2c (FIG. 21 and 22). In the case of the small beam diameter d (m1, n) shown in FIG. 21, the normalized signal intensity R (m1, n) is large because most of the ultrasonic beam is reflected by the small defect 2c. On the other hand, in the case of the large beam diameter d (m1, n) shown in FIG. 22, a part of the ultrasonic beam is reflected, but most of it passes outside the small defect 2c, so that the normalized signal intensity R (m2). , N) becomes smaller.

As shown in FIG. 2, in the ultrasonic flaw detection method, it is next determined whether or not the measurement for all the beam diameters in the change range of the predetermined beam diameter is completed (step S06). If it is determined that the process has not been completed (step S06 NO), steps S04 to S06 are repeated. If it is determined that the process has been completed (YES in step S06), the process proceeds to the next step.

Next, the dependency characteristic storage unit 42 acquires the dependence of the normalized signal intensity R on the beam diameter d (step S07). That is, the relationship between each beam diameter d and the normalized signal intensity R at each beam diameter d is stored in a predetermined format.

As shown above, in each case of the large single defect 2a, the two small defects 2b, and the one small defect 2c, for example, the small beam diameter d (m1, n) and the large beam diameter d (m2, m2). As in n), the result is that the dependence of the normalized signal intensity R (m, n) on the beam diameter d of the ultrasonic wave is different. That is, as shown in FIG. 23, the characteristics of the normalized signal intensity R (m, n) with respect to the beam diameter d (m, n) do not change in the case of the large single defect 2a, and in the case of the two small defects 2b. It has the characteristics of increasing and decreasing in the case of one small defect 2c.

As described above, the characteristic of the normalized signal intensity R (m, n) with respect to the beam diameter d (m, n) can be used as test data in advance by assuming the size of the defect 2 or by using it as a parameter. It can be collected. Further, FIG. 23 shows the characteristics of a large defect and a small defect of a certain size, but if the diameter of the defect 2 is further refined, a characteristic curve corresponding to each can be obtained.

The dependent characteristic data collected in advance and the dependent characteristic data collected in the flaw detection test are accepted as external inputs via the input unit 70, and are stored in the dependent characteristic storage unit 42 as a dependent characteristic database. The dependent characteristic database may be a set of two-dimensional data (R, d), or may be a function format that approximates the characteristic curve as shown in FIG. 23 by polynomial approximation or the like.

As shown in FIG. 2, in the ultrasonic flaw detection method, it is next to determine whether or not the measurement of the measurement coordinate range is completed (step S08). That is, when the flaw detection is performed on a plurality of measurement coordinates P, it is determined whether or not the flaw detection is completed for all the measurement coordinates P. If it is determined that the process has not been completed (step S08 NO), steps S02 to S08 are repeated.

When it is determined that the flaw detection has been completed for all the measured coordinates P (step S08 YES), the dependent characteristic storage unit 42 further determines the dependent characteristic of the normalized signal strength R (m2, n) to the measured coordinates P. Is saved (step S09). The details of step S09 will be described after the description of the next step S10.

Finally, the defect determination unit 37 determines the defect (step S10).

The defect discrimination unit 37 normalizes the signal intensity R (m, n) of each reflected wave by the ultrasonic beam having a plurality of beam diameters d (m, n) switched by the beam diameter setting switching unit 35, or standardizes the signal intensity R (m, n). The relative value of the signal intensity R (m, n) is collated with the beam diameter dependence database stored in the dependency characteristic storage unit 42, and the situation of the defect 2, that is, the size of the defect 2 and the like are determined.

At this time, for example, the characteristic data acquired for the inspection target 1 and stored in the dependent characteristic storage unit 42 and the characteristic data in the characteristic database that the dependent characteristic storage unit 42 accepts and stores in advance via the input unit 70. The correspondence between the characteristic data may be determined by, for example, pattern recognition. Alternatively, for example, the closest characteristic data in the characteristic database may be selected by the least squares method.

The defect discrimination unit 37 may discriminate defects from the tendency of the normalized signal intensity R (m, n) to change with respect to the change in the beam diameter d (m, n).

As shown in FIG. 23, the magnitude of the defect depends on the change in the normalized signal intensity R (m, n) with respect to the change in the beam diameter d, that is, the dependent characteristic of the normalized signal intensity R (m, n) on the beam diameter d. Can be determined.

The above is the determination method based on the change in the normalized signal intensity R (m, n) due to the switching of the beam diameter d by the beam diameter setting switching unit 35. The method according to the above may be used. That is, as described below, the measurement coordinate setting switching unit 31 switches the measurement coordinate number n in addition to the switching of the beam diameter d, and the determination method based on the change in the normalized signal intensity R (m, n) due to this switching. Is.

That is, in the present embodiment, when the measurement coordinate setting switching unit 31 of the calculation unit 30 switches the measurement coordinate number n, the measurement coordinate number n, which is an aspect of the ultrasonic beam passing through the predetermined position in the inspection target 1, is The first condition such that the first measurement coordinate number n1 and the measurement coordinate number n, which is an aspect of the ultrasonic beam passing through a predetermined position in the inspection target 1, are different from the first measurement coordinate number n1. It is also possible to set a second condition such that the measurement coordinate number n2 of 2 is obtained.

The switching of the measurement coordinate number n by the measurement coordinate setting switching unit 31 is set by at least one of the selection of the ultrasonic element 11 constituting the driven element group and the delay time for each of the selected plurality of ultrasonic elements 11. It is possible.

Instead of switching the measurement coordinate number n, the measurement coordinate setting switching unit 31 may scan the entire ultrasonic array probe 10 or may change the driven element group as in the linear array. ..

FIG. 24 is a conceptual cross-sectional view illustrating the difference between the first beam diameter and the measurement position in the case where two small defects are present in the ultrasonic flaw detection method according to the embodiment. The case of the measurement position Pa of the above is shown, and FIG. 25 shows the case of the second measurement position Pb. The case where two small defects 2b are present is shown as an example.

Further, FIG. 26 is a conceptual cross-sectional view illustrating the difference between the second beam diameter and the measurement position in the case where two small defects are present in the ultrasonic flaw detection method according to the embodiment. The case of the first measurement position Pa is shown, and FIG. 27 shows the case of the second measurement position Pb.

The beam diameters d (m1, n1) and d (m1, n2) of the ultrasonic beam having the beam diameter number m1 shown in FIGS. 24 and 25 are the ultrasonic beams having the beam diameter number m2 shown in FIGS. 26 and 27. It is smaller than the beam diameters d (m1, n1) and d (m1, n2).

First, the case of the beam diameter number m1 having the smaller beam diameter shown in FIGS. 24 and 25 will be described. Now, as shown in FIG. 24, at the first measurement coordinate number n1, the beam diameter d (m1, n1) is substantially equal to the size of one of the two small defects 2b, and almost the entire amount of the ultrasonic beam is reflected. To. On the other hand, as shown in FIG. 25, at the measurement coordinate number n2, the ultrasonic beam deviates from the center of one of the small defects 2b, so that only a small part is reflected. If the measurement coordinate number n is further deviated, reflection occurs in another small defect 2c, so that the normalized signal intensity R (m1, n1) increases again.

Therefore, in the case of the beam diameter d (m1, n1) of the ultrasonic beam having the beam diameter number m1, the normalized signal intensity R (m1, n1) in the case of the measurement coordinate number n1 is the standard in the case of the measurement coordinate number n2. Normalized signal strength R (m1, n2) is larger.

Next, the case of the beam diameter number m2 having a large beam diameter shown in FIGS. 26 and 27 will be described. Now, as shown in FIG. 26, at the first measurement coordinate number n1, the beam diameter d (m2, n1) is substantially equal to the size of one of the two small defects 2b, and almost the entire amount of the ultrasonic beam is reflected. To. On the other hand, as shown in FIG. 27, at the measurement coordinate number n2, the ultrasonic beam does not cover all the small defects 2b on one side, but covers a part of the small defects 2b on the other side. Therefore, the total of the reflections from each of the two small defects 2b is almost constant.

Therefore, in the case of an ultrasonic beam having a beam diameter d (m1, n1), that is, a beam diameter number m1, the normalized signal intensity R (m1, n1) in the case of the measurement coordinate number n1 is the case of the measurement coordinate number n2. It is larger than the standardized signal strength R (m1, n2).

FIG. 28 is a graph showing a change in normalized signal strength with respect to a change in measurement coordinates when two small defects are present in the ultrasonic flaw detection method according to the embodiment. The horizontal axis is the coordinate value (measurement coordinate number) n of the measurement coordinate P, and the vertical axis is the normalized signal strength R (m, n).

In the solid line curve E, when the ultrasonic beam diameter d (1, n) is about the same as the respective diameters of the small defects 2b, in the dotted line curve F, the ultrasonic wave beam diameter d (2, n) is the small defect 2b. The case where it is larger than each diameter of is shown.

When the beam diameter d (1, n) of the ultrasonic wave is about the same as the diameter of each of the small defects 2b, the amount of reflection gradually increases as the value n of the measurement coordinates P approaches the value corresponding to one position of the small defect 2b. Will increase. Further, when the value corresponds to one position of the small defect 2b, almost the entire amount of the ultrasonic beam is reflected. When the coordinates n are further changed, the ultrasonic beam passes between the two small defects 2b, so that the reflection component is reduced. Further, when the value corresponds to the other position of the small defect 2b, almost the entire amount of the ultrasonic beam is reflected again. If the position is further displaced, the amount of reflection decreases.

From the above changes, two peaks are generated in the normalized signal intensity R (m, n) with respect to the change in the measurement coordinate P on the horizontal axis.

On the other hand, when the beam diameter d (2, n) of the ultrasonic wave is larger than the range in which the two small defects 2b exist and covers the two small defects 2b, in the range covering these, the range is covered. Even if the measured coordinates change, the reflected wave intensity hardly changes, so that one peak has a wide width.

FIG. 29 is a graph showing a change in normalized signal strength with respect to a change in measurement coordinates when one major defect is present in the ultrasonic flaw detection method according to the embodiment. That is, it is a graph showing a change in the normalized signal strength when the measurement coordinates are changed, and is a case of a single defect. Similar to FIG. 28, the horizontal axis is the measurement coordinate P, and the vertical axis is the normalized signal strength R (m, n). Further, in the solid line curve E, when the ultrasonic beam diameter d (1, n) is about the same as the diameter of the large defect 2a (FIG. 17), the dotted line curve F is the ultrasonic wave beam diameter d (2, n). Is larger than the diameter of the large defect 2a.

29 shows the case where the defect is two small defects 2c in FIG. 28, whereas FIG. 29 shows the case where one large defect 2a is present.

When the beam diameter d is large, the signal intensity does not change significantly as shown in FIG. 29. This is because the size of the defect 2a is larger than the beam diameter d, so that the ultrasonic beam is irradiated to somewhere in the defect 2a and almost the entire amount is reflected.

After step S09, as described above, the defect determination unit 37 determines the defect (step S10).

The defect determination unit 37 has a standardized signal intensity R (m, n) or a standardized signal intensity R (m, n) of each reflected wave by the ultrasonic beam for a plurality of measurement coordinates P switched by the measurement coordinate setting switching unit 31. The relative values of m and n) are collated with the beam diameter dependence database stored in the dependency characteristic storage unit 42 to determine the situation of the defect 2, that is, the size of the defect 2.

As described above, the magnitude of the defect is discriminated by the change in the normalized signal strength R (m, n) with respect to the change in the measured coordinate P, that is, the dependent characteristic of the normalized signal strength R (m, n) depending on the measured coordinate. Is possible.

As described above, according to the present embodiment, highly accurate flaw detection inspection is possible, such as distinguishing between single defects and group defects in ultrasonic flaw detection.

[Other embodiments]
Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention.

For example, in the embodiment, ultrasonic waves are individually transmitted from each of the ultrasonic elements 11 constituting the driven element group, the reflected waves are individually collected, and then synthesized as signal processing to be virtual. It is treated as forming an ultrasonic beam, but is not limited to this. That is, the ultrasonic element 11 constituting the driven element group may be actually transmitted in consideration of the delay time of each, and an ultrasonic beam may be actually formed to obtain a reflected wave.

Further, as shown by the above equation (1), since the ultrasonic beam diameter d is proportional to (Lf · λ / D), the ultrasonic beam diameter d can be changed by changing the wavelength λ of the ultrasonic wave. You may use the method of preparing. The wavelength λ can be changed by changing the area or thickness of the vibrator of the ultrasonic element 11, and there is a method of exchanging these with an ultrasonic array probe having the changed ultrasonic element 11.

In addition, the embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 ... Inspection target, 2 ... Defect, 2a ... Single defect, 2b, 2c ... Small defect, 3 ... Focus, 5 ... Acoustic contact medium, 10 ... Ultrasonic array probe, 11 ... Ultrasonic element, 12 ... Holding part, 15 ... Moving drive unit, 20 ... Transmission / reception unit, 21 ... Potential difference application unit, 22 ... Switching unit, 23 ... AD conversion unit, 30 ... Calculation unit, 31 ... Measurement coordinate setting switching unit (setting switching unit), 32 ... Delay time Calculation unit, 33 ... Composite calculation unit, 34 ... Damage detection image drawing unit, 35 ... Beam diameter setting switching unit (setting switching unit), 36 ... Standardized signal strength calculation unit, 37 ... Defect discrimination unit, 40 ... Storage unit, 41 ... Signal processing information storage unit, 42 ... Dependent characteristic storage unit, 50 ... Control unit, 60 ... Display unit, 70 ... Input unit, 100 ... Ultrasonic flaw detector, 110 ... Test board, C ... Center of driven element group, P ... Measurement coordinates

Claims (5)

An ultrasonic array probe having a plurality of ultrasonic elements arranged in a predetermined direction for transmitting ultrasonic waves to the inspection target and receiving the ultrasonic waves reflected by the inspection target.
A plurality of the ultrasonic elements constituting the driven element group are selected, a delay time for mutually shifting the timing of transmission / reception of ultrasonic waves by each of the selected ultrasonic elements is calculated, and the calculated delay time is set to the calculated delay time. A calculation unit that determines the existence status of defects inherent in the inspection target based on the ultrasonic waves transmitted and received based on the above.
Equipped with
The calculation unit has a first condition in which the mode of the ultrasonic beam to a predetermined position in the inspection target is the first mode, and a second condition in which the mode is different from the first mode. Is configured to be switchable ,
The ultrasonic flaw detector is characterized in that the beam diameter is different from the first aspect and the second aspect of the ultrasonic beam, and the calculation unit further includes a beam diameter setting switching unit for switching the beam diameter . The ultrasonic flaw detector according to claim 1, wherein the beam diameter setting switching unit sets the beam diameter according to the number of ultrasonic elements constituting the driven element group . The ultrasonic flaw detector according to claim 1 , wherein the beam diameter setting switching unit sets the beam diameter by changing the focal depth of the ultrasonic beam . The first aspect and the second aspect of the ultrasonic beam are characterized in that the measurement coordinates for irradiating the ultrasonic beam are different and the measurement coordinate setting switching unit for setting and switching the measurement coordinates is further provided. The ultrasonic flaw detector according to 1 . Each of the plurality of ultrasonic elements constituting the driven element group of the ultrasonic array probe transmits ultrasonic waves to the inspection target, and the plurality of the ultrasonic elements receive the reflected waves from the inspection target. Steps and
The setting switching unit has a first condition in which the mode of the ultrasonic beam formed by ultrasonic waves transmitted from each of the plurality of ultrasonic elements is the first mode, and a second mode different from the first mode. The setting step to set the second condition and
The defect discriminating unit determines the defect based on the first reflected signal of the ultrasonic beam of the first aspect and the second reflected signal of the ultrasonic beam of the second aspect, and a defect discriminating step.
Have,
The first aspect and the second aspect of the ultrasonic beam have different beam diameters of the ultrasonic beam, and further include a beam diameter switching step for changing the beam diameter.
An ultrasonic flaw detection method characterized by this.

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