JP3615942B2 - Ultrasonic flaw detection apparatus and ultrasonic flaw detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method used for inspection of a welded portion and inspection of plate materials, pipe materials, and the like. In particular, the present invention relates to an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method that employ a so-called “ultrasonic oblique flaw detection method” that uses ultrasonic waves that travel at an inclined angle with respect to the flaw detection surface of a specimen.
[0002]
[Prior art]
Conventionally, for this type of ultrasonic flaw detection method, for example, “ultrasonic flaw detection method (revised new edition)”, edited by Japan Society for the Promotion of Science and Steelmaking 19th Committee, Nikkan Kogyo Shimbun, July 30, 1974 This is described in detail in “Issuance of a revised Japanese edition”, “December 20, 1978, issue of a revised 3rd edition”, pages 180 to 199 (hereinafter referred to as “Document A”).
[0003]
A conventional ultrasonic flaw detector and ultrasonic flaw detection method will be described with reference to the drawings. FIG. 11 is a diagram showing a conventional ultrasonic oblique angle flaw detection method disclosed in Document A, for example.
[0004]
In FIG. 11, the test body 1 has a base material part 2 and a welded part 5. 3 is the surface of the test body 1, and 4 is the bottom surface of the test body 1. Reference numeral 6 denotes an acoustic discontinuity existing in the test body 1. Further, a probe 7 is placed on the surface 3 of the test body 1.
[0005]
There are various acoustic discontinuities 6 such as cracks in the first layer weld during welding, crater cracks at the beginning of welding, poor fusion, poor penetration, slag entrainment, blow holes, worm holes, hot cracks, There are material differences from the surrounding medium due to foreign matter contamination. In addition, a mixed foreign material portion, a crack, a flaw, or the like that already exists in the material itself without being related to the welding operation corresponds to the acoustic discontinuity portion 6. Hereinafter, these acoustic discontinuities 6 will be referred to as defects 6 for the sake of simplicity.
[0006]
An ultrasonic pulse is transmitted to the inside of the test body 1 from the probe 7 placed on the surface 3 of the test body 1 corresponding to the flaw detection surface. In the figure, the propagation direction of the ultrasonic pulse is indicated by a solid line with an arrow, and the angle “θ” is the refraction angle of the ultrasonic beam. The ultrasonic pulse irradiated to the defect 6 and reflected by the defect 6 is received as an echo by the probe 7.
[0007]
In FIG. 11, the ultrasonic pulse transmitted from the probe 7 is reflected once by the bottom surface 4 of the test body 1 and then irradiated to the defect 6, and the ultrasonic pulse reflected by the defect 6 is tested. A case is shown in which the probe 7 receives the signal as an echo after being reflected once by the bottom surface 4 of the body 1. Such a method involving a single reflection at the bottom surface 4 of the test body 1 is called a “single reflection method”. There is also used a method in which an ultrasonic pulse is directly applied to the defect 6 from the probe 7 without being reflected by the bottom surface 4 and the ultrasonic pulse reflected by the defect 6 is directly received by the probe 7. This method is called a “direct shot method”.
[0008]
The position of the defect 6 is estimated as follows. Although not shown, the time difference between the time when the ultrasonic pulse is transmitted from the probe 7 and the time when the echo is received by the ultrasonic flaw detector electrically connected to the probe 7, that is, the ultrasonic The time required for the sound wave pulse to propagate through the specimen 1 is measured. Since this time is the time required for the ultrasonic pulse to travel back and forth from the probe 7 to the defect 6, it is divided by 2 to obtain the one-way time, and the one-way time is calculated from this time and the speed of sound in the specimen 1. Find the beam path.
[0009]
This beam path is indicated by “Wy” in the figure. Using the beam path “Wy”, the refraction angle “θ”, and the thickness “t” of the specimen 1, the position of the defect 6, that is, the depth “from the surface 3 of the specimen 1 to the defect 6”. d ”and the horizontal distance“ y ”to the probe 7 and the defect 6 are estimated. Note that, in the case of the above-described direct irradiation method, the thickness “t” of the specimen 1 is not required to estimate the position of the defect 6.
[0010]
In the method of estimating the position of the defect 6 described above, the ultrasonic beam travels straight along a straight line as if it were light. That is, the expansion of the ultrasonic beam due to diffraction is negligible. However, in practice, the transducer constituting the probe 7 as a sound source and a reception source has a finite aperture area, so that the ultrasonic beam expands due to diffraction. Therefore, if the position of the defect 6 is estimated by ignoring the spread of the ultrasonic beam due to diffraction by simply relying on the refraction angle “θ” and the beam path length “Wy”, the estimated position and the actual position There may be a difference between them. In particular, when the opening area of the transducer constituting the probe 7 is small or when the refraction angle “θ” is large even with the same opening area, the equivalent opening area becomes small. The difference between the positions is not negligible. That is, the estimation method described above has a problem that the estimation accuracy of the position of the defect 6 is poor.
[0011]
On the other hand, there is an attempt to improve the estimation accuracy of the position of the defect 6 by actively using the spread due to diffraction of the ultrasonic beam. For example, a method to which aperture synthetic signal processing disclosed in JP-A-2-278149, JP-A-2-248855, or JP-A-5-172789 is applied corresponds to this.
[0012]
In the aperture synthetic signal processing, information on the propagation delay time of the ultrasonic wave propagating between the equivalent transmission / reception point of the ultrasonic beam transmitted from the probe 7 and the image reproduction point is necessary. This information is required for each image reproduction point. Therefore, it is necessary to accurately grasp the equivalent transmission / reception point of the ultrasonic beam and the propagation delay time of the ultrasonic wave. However, in the above-mentioned patent publication, there is no description about these.
[0013]
Apparent oscillator theory is known as a theory regarding an ultrasonic beam transmitted and received by the oblique probe 7 used in the ultrasonic oblique flaw detection method. As for apparent oscillator theory, for example, “New Nondestructive Inspection Handbook”, edited by Japan Nondestructive Inspection Association, Nikkan Kogyo Shimbun, October 15, 1992, first edition, 1st edition, pages 291 to 292 Page (hereinafter abbreviated as “Document B”).
[0014]
FIG. 12 is a diagram for explaining the apparent oscillator theory cited from the document B. In addition, although the figure shown in FIG. 12 and the figure shown by the said literature B have reversed right and left, there is no influence on the following description. The apparent oscillator theory will be described below with reference to FIG.
[0015]
In FIG. 12, “α” and “θ” are the incident angle and the refraction angle of the probe 7, respectively. The probe 7 includes a wedge 71 and a vibrator 72. Reference numeral 72 is an actual vibrator, and reference numeral 73 is an apparent vibrator. The actual center of the vibrator 72 and the center of the apparent vibrator 73 are indicated by P and P1, respectively. In the drawing, the opening lengths of the actual vibrator 72 and the apparent vibrator 73 are represented by H and H, respectively._RIs shown. Further, the actual distance from the center P of the vibrator to the incident point O and the distance from the apparent vibrator center P1 to the incident point O are indicated as l1 and l2, respectively.
[0016]
The incident point is a point where a straight line passing through the point P perpendicular to the actual opening of the vibrator 72 intersects the surface 3 of the specimen 1. This incident point is a point on the boundary surface where the wedge 71 and the specimen 1 are in contact. In this sense, it is also a point on the surface 3 of the test body 1, in other words, a point on the surface where the wedge 71 is in contact with the surface 3. As described above, a point belonging to the specimen 1 side is also called an incident point, but here, a point belonging to the probe 7 is called an incident point.
[0017]
The ultrasonic wave transmitted from the actual vibrator 72 propagates in the wedge 71, is refracted by the surface 3 of the test body 1, and propagates into the test body 1. At this time, if the wedge 71 is regarded as the same material as that of the test body 1 and an ultrasonic beam, that is, a sound field created by the probe 7 can be considered, handling of the sound field created by the probe 7 is easy. It becomes. Thus, the theory that simply describes the sound field created by the probe 7 by regarding the material of the wedge 71 as the same material as that of the test body 1 is the apparent oscillator theory.
[0018]
According to the apparent oscillator theory, the distance l1 from the center P of the actual oscillator 72 to the incident point O and the distance l2 from the center P1 of the apparent oscillator 73 to the incident point O are as follows. There is a relationship as shown in Equation 1.
[0019]
l2 = l1 × tan (α) / tan (θ) Expression 1
[0020]
Propagation of ultrasonic waves between this transmission / reception point and the image reproduction point, assuming that the center P1 of the apparent transducer 73 located at the distance l2 given by the above equation 1 is an equivalent transmission / reception point of the ultrasonic beam. A method of performing aperture synthesis signal processing using a delay time is described in detail in International Publication No. WO 97/36175.
[0021]
We tried various image reproduction experiments by changing the test conditions according to the method disclosed in the above-mentioned International Publication No. WO97 / 36175. In these image reproductions, for simplicity, the ultrasonic pulse transmitted from the probe 7 is irradiated directly on the defect 6, and the ultrasonic pulse reflected by the defect 6 is reflected on the bottom surface 4. First, it is assumed that the signal is received directly by the probe 7.
[0022]
The results shown in FIG. 13 to FIG. 15 are examples of experimental results, and show reproduced images obtained in the experiment. The test conditions are as follows. The test body 1 was a steel material having a thickness of 60 mm, and a slit having a height of 5 mm and a width of 1 mm was provided by machining at a distance of 5 mm from the bottom surface 4. The slit was regarded as a defect 6 and an image was reproduced. As the probe 7, a wide-band probe 7 having a frequency of 2 MHz and a refraction angle of 74 ° and a wide bandwidth was used.
[0023]
13 to 15, white squares denoted by reference numerals 8 to 10 indicate actual slit positions and slit outlines. Reference numeral 4 denotes a bottom surface of the test body 1. As can be seen from these drawings, the slit 8 used in the experiment shown in FIG. 13 is perpendicular to the bottom surface 4 of the test body 1. Further, the slit 9 used in the experiment shown in FIG. 14 is inclined 15 ° toward the probe 7. Further, the slit 10 used in the experiment shown in FIG. 15 is inclined by 15 ° on the opposite side to the probe 7. In each figure, an arrow is attached to indicate a direction when the slits 8 to 10 are viewed from the probe 7.
[0024]
As can be seen from FIG. 13, the position of the reproduced image is considerably different from the actual position of the slit 8 and is reproduced at a position shifted in the direction opposite to the probe 7. Similarly in FIGS. 14 and 15, the position of the reproduced image is considerably shifted in the direction opposite to the probe 7 from the actual slits 9 and 10. Further, the position of the reproduced image is also shifted in the vertical direction as compared with the actual positions of the slits 8 to 11.
[0025]
As described above, when the image reproduction is performed by using the apparent oscillator theory and regarding the center P1 of the apparent oscillator 73 as an equivalent transmission / reception point, the actual defect 6 and the reproduced image are located at positions that are considerably separated from each other. It turned out that it may become. Further, it was found that the difference between the two positions is small when the distance l1 shown in FIG. 12 in the wedge 71 of the probe 7 is short, but increases when the distance l1 is long.
[0026]
[Problems to be solved by the invention]
As described above, using the conventional apparent oscillator theory, if the center P1 of the apparent oscillator 73 is regarded as an equivalent transmission / reception point and aperture synthetic signal processing is performed to reproduce the image of the defect 6, the defect It has been found that there is a problem that the position estimation accuracy of 6 is not very good.
[0027]
The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method that can further improve the accuracy of a reproduced image as compared with the conventional technique. .
[0028]
[Means for Solving the Problems]
An ultrasonic flaw detection apparatus according to the present invention includes a wedge and a vibrator, and is driven by a transmission signal to transmit an ultrasonic pulse obliquely with respect to the flaw detection surface of the test specimen. A probe that receives the ultrasonic pulse reflected by the unit as an echo, and a scanning mechanism that moves the probe over a predetermined scanning range of the test body and outputs a spatial position of the probe And the transmission signal generated and output to the probe, the echo received from the probe is input and stored, and the probe when the echo is received from the scanning mechanism unit The spatial position of the child is input and stored, and a transmission / reception point equivalent to the ultrasonic transmission / reception surface of the probe is taken at the center of the actual transducer, and from the equivalent transmission / reception pointOpenAs a path through which the ultrasonic wave propagates to the image reproduction point, which is a point for obtaining the acoustic discontinuity as an image by mouth synthesis signal processing, the equivalent transmission / reception point through the probe incident point is used as the path. A path to the image reproduction point is obtained, and a time required for the ultrasonic wave to propagate along the path is a propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point. None, the distance from the center of the actual vibrator to the incident point is l₁, L is the distance from the incident point to the image reproduction point, and V is the sound velocity of the ultrasonic wave at the wedge.₁, The sound velocity of the ultrasonic wave in the specimen is V₂Then, the propagation delay time τThe,formulaτ = l₁/ V₁+ L / V₂ Calculate fromA transmission / reception device that reproduces an image of the acoustic discontinuity by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe It is.
[0029]
An ultrasonic flaw detection apparatus according to the present invention includes a wedge and a vibrator, and is driven by a transmission signal to transmit an ultrasonic pulse obliquely with respect to the flaw detection surface of the test specimen. A probe that receives the ultrasonic pulse reflected by the unit as an echo, and a scanning mechanism that moves the probe over a predetermined scanning range of the test body and outputs a spatial position of the probe And the transmission signal generated and output to the probe, the echo received from the probe is input and stored, and the probe when the echo is received from the scanning mechanism unit The spatial position of the child is input and stored, and a transmission / reception point equivalent to the ultrasonic transmission / reception surface of the probe is taken at the center of the actual transducer, and from the equivalent transmission / reception pointOpenA path along the sound ray that satisfies Snell's refraction law is obtained as a path through which the ultrasonic wave propagates to the image reproduction point, which is a point for obtaining the acoustic discontinuity as an image by mouth synthesis signal processing. The time required for the ultrasonic wave to propagate along the transmission line is defined as a propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point. Is the distance to the intersection where the surface intersects the surface of the specimen_R, The distance from the intersection to the image reproduction point is L_R, The sound velocity of the ultrasonic wave in the wedge is V₁, The sound velocity of the ultrasonic wave in the specimen is V₂Then, the propagation delay time τThe,formulaτ = l_R/ V₁+ L_R/ V₂ Calculate fromA transmission / reception device that reproduces an image of the acoustic discontinuity by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe It is.
[0030]
In the ultrasonic flaw detection apparatus according to the present invention, the probe is driven by a transmission signal to transmit an ultrasonic pulse at a transmission angle inclined with respect to the flaw detection surface of the test specimen, and the acoustic wave in the test specimen is also transmitted. The ultrasonic pulse reflected by the discontinuous portion is received as an echo at a reception angle that is different from the transmission angle with respect to the flaw detection surface.
[0031]
Furthermore, in the ultrasonic flaw detection apparatus according to the present invention, the probe is driven by a transmission signal and transmits an ultrasonic pulse at a transmission angle inclined with respect to the flaw detection surface of the test specimen, and the acoustic wave in the test specimen is also transmitted. The ultrasonic pulse reflected by the discontinuous portion is received as an echo at a reception angle that is inclined with respect to the flaw detection surface as the transmission angle.
[0032]
In the ultrasonic flaw detection method according to the present invention, the scanning mechanism unit moves the probe composed of the wedge and the transducer over a predetermined scanning range of the specimen, and generates a transmission signal to generate the probe. Transmitting to the probe, and transmitting the ultrasonic pulse obliquely with respect to the flaw detection surface of the specimen by the probe, and reflected by the acoustic discontinuity in the specimen by the probe A reception step of receiving the ultrasonic pulse as an echo; and a spatial position of the probe when the echo received from the probe is input and stored and the echo is stored from the scanning mechanism unit A storage step for inputting and storing, and a transmission / reception point equivalent to the ultrasonic transmission / reception surface of the probe, at the center of the actual transducer, from the equivalent transmission / reception pointOpenAs a path through which the ultrasonic wave propagates to the image reproduction point, which is a point for obtaining the acoustic discontinuity as an image by mouth synthesis signal processing, the equivalent transmission / reception point through the probe incident point is used as the path. A path to the image reproduction point is obtained, and a time required for the ultrasonic wave to propagate along the path is a propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point. None, the distance from the center of the actual vibrator to the incident point is l₁, L is the distance from the incident point to the image reproduction point, and V is the sound velocity of the ultrasonic wave at the wedge.₁, The sound velocity of the ultrasonic wave in the specimen is V₂Then, the propagation delay time τThe,formulaτ = l₁/ V₁+ L / V₂ Calculate from, And a signal processing step of reproducing the image of the acoustic discontinuity portion by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe. .
[0033]
In the ultrasonic flaw detection method according to the present invention, the scanning mechanism unit moves the probe composed of the wedge and the transducer over a predetermined scanning range of the specimen, and generates a transmission signal to generate the probe. Transmitting to the probe, and transmitting the ultrasonic pulse obliquely with respect to the flaw detection surface of the specimen by the probe, and reflected by the acoustic discontinuity in the specimen by the probe A reception step of receiving the ultrasonic pulse as an echo; and a spatial position of the probe when the echo received from the probe is input and stored and the echo is stored from the scanning mechanism unit A storage step for inputting and storing, and a transmission / reception point equivalent to the ultrasonic transmission / reception surface of the probe, at the center of the actual transducer, from the equivalent transmission / reception pointOpenA path along the sound ray that satisfies Snell's refraction law is obtained as a path through which the ultrasonic wave propagates to the image reproduction point, which is a point for obtaining the acoustic discontinuity as an image by mouth synthesis signal processing. The time required for the ultrasonic wave to propagate along the transmission line is defined as a propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point. Is the distance to the intersection where the surface intersects the surface of the specimen_R, The distance from the intersection to the image reproduction point is L_R, The sound velocity of the ultrasonic wave in the wedge is V₁, The sound velocity of the ultrasonic wave in the specimen is V₂Then, the propagation delay time τThe,formulaτ = l_R/ V₁+ L_R/ V₂ Calculate from, And a signal processing step of reproducing the image of the acoustic discontinuity portion by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe. .
[0034]
In the ultrasonic flaw detection method according to the present invention, the transmission step generates a transmission signal and outputs the transmission signal to the probe, and the ultrasonic pulse is inclined with respect to the flaw detection surface of the specimen by the probe. The ultrasonic wave reflected by the acoustic discontinuity in the specimen by the probe is tilted different from the transmission angle with respect to the flaw detection surface. It is received as an echo at the reception angle.
[0035]
Furthermore, in the ultrasonic flaw detection method according to the present invention, the transmission step generates a transmission signal and outputs it to the probe, and the ultrasonic pulse is tilted with respect to the flaw detection surface of the specimen by the probe. The ultrasonic wave reflected by the acoustic discontinuity in the test body by the probe is received with the same inclination as the transmission angle with respect to the flaw detection surface. Received as an echo at an angle.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
An ultrasonic flaw detector and an ultrasonic flaw detection method according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an ultrasonic flaw detector using an ultrasonic oblique flaw detection method according to Embodiment 1 of the present invention. In addition, in each figure, the same code | symbol shows the same or equivalent part.
[0037]
In FIG. 1, 1 is a test body, 3 is the surface of the test body 1, 4 is the bottom surface of the test body 1, and 6 is a defect. The ultrasonic flaw detector includes a probe 7 placed on the test body 1, a transmission / reception device 80 connected to the probe 7, and a scanning mechanism unit 90 that scans and drives the probe 7.
[0038]
In the figure, the transmission / reception device 80 includes a control unit 81, a transmission unit 82, a reception unit 83, a signal processing unit 84, and a position detection unit 85 of the probe 7. The scanning mechanism unit 90 includes a position detection sensor for the probe 7 (not shown).
[0039]
Further, in the same figure, the probe 7 is connected to a transmission unit 82 and a reception unit 83 by signal lines. The receiving unit 83 is connected to the signal processing unit 84. The position detection unit 85 is connected to the signal processing unit 84. The control unit 81 is connected to the transmission unit 82, the reception unit 83, the signal processing unit 84, the position detection unit 85, and the scanning mechanism unit 90.
[0040]
Further, in the figure, the scanning mechanism unit 90 is connected to a position detection unit 85. An output signal from the position detection sensor of the scanning mechanism unit 90 is input to the position detection unit 85. Information on the position of the probe 7 detected by the position detector 85 is input to the signal processor 84.
[0041]
If the position information of the probe 7 can be obtained only by the signal from the control unit 81 without using the information from the position detection unit 85, the information from the control unit 81 is used. Position information may be input to the signal processing unit 84 using only.
[0042]
Further, the signal processing unit 84 has a memory therein, although not shown. In this memory, various results calculated and calculated in the signal processing unit 84 are appropriately stored, and input signals input to the signal processing unit 84 are appropriately stored.
[0043]
Although not shown, a signal indicating the processing status is appropriately input to the control unit 81 from the signal processing unit 84. Based on the input signal, the control unit 81 outputs control signals to the transmission unit 82, the reception unit 83, the signal processing unit 84, the position detection unit 85, and the scanning mechanism unit 90 to control them.
[0044]
Next, the operation of the ultrasonic flaw detector according to Embodiment 1 described above will be described with reference to the drawings. 2 and 3 are diagrams showing the operation of the ultrasonic flaw detector according to Embodiment 1 of the present invention.
[0045]
First, the operation of the ultrasonic flaw detector shown in FIG. 1 will be described. In FIG. 1, an excitation signal is transmitted from the transmitter 82 to the probe 7. With this excitation signal, an ultrasonic pulse is transmitted from the probe 7, and the ultrasonic pulse propagates into the test body 1. The ultrasonic pulse propagating through the specimen 1 is reflected by the defect 6, propagates again through the specimen 1, and is received as an echo by the probe 7. The echo signal is amplified by the receiving unit 83 and then transmitted to the signal processing unit 84.
[0046]
On the other hand, as described above, the position information of the probe 7 that has transmitted the ultrasonic pulse and received the echo is input to the signal processing unit 84.
[0047]
These operations are executed while the probe 7 scans the probe 7 over a predetermined scanning range.
[0048]
In the signal processing unit 84, aperture synthesis signal processing is executed based on the echo and the position information of the probe 7, and signal processing for image reproduction of the defect 6 is performed. In this signal processing, details of the signal processing when the equivalent transmission / reception point of the probe 7 is set to the center P1 of the apparent transducer 73 is disclosed in International Publication No. WO 97/36175.
[0049]
The present application discloses that an equivalent transmission / reception point of the probe 7 in this signal processing is set to a point different from the center P1 of the apparent transducer 73. This will be described below with reference to FIGS.
[0050]
In FIG. 2, P indicates the center of the actual vibrator 72, and O indicates the incident point. In FIG. 2, the distance from the center P of the actual vibrator 72 to the incident point O is indicated as l1, and the distance from the incident point O to the image reproduction point Q is indicated as L.
[0051]
When the image reproduction point Q is in the far field, the ultrasonic wave propagation delay time τ from the actual center P of the transducer 72 to the image reproduction point Q can be expressed by the following equation 2. V₁And V₂Are the sound speeds of the ultrasonic waves in the wedge 71 and the test body 1, respectively.
[0052]
τ = l₁/ V₁+ L / V₂                                    ... Formula 2
[0053]
The first term on the right side of Equation 2 is a propagation delay time caused by the propagation of the ultrasonic pulse from the center P of the vibrator 72 to the incident point O. Further, the second term on the right side of Equation 2 is a propagation delay time caused by the propagation of the ultrasonic pulse at the incident point O to the image reproduction point Q.
[0054]
Equation 2 assumes that the material of the wedge 71 is the same material as that of the test body 1, and when the image reproduction point Q and the incident point O are connected by a straight line, the equivalent transmission / reception point is the position of the image reproduction point Q. It is suggested that it changes. This is shown in FIG. As shown in FIG. 3, for example, when the image reproduction point Q is at the position 6a, the equivalent transmission / reception point is (l1 / V) from the incident point O on the straight line connecting 6a and the incident point O.₁) V₂, The point Pa is located at a distance apart. As another example, when the image reproduction point Q is at the position 6b, the equivalent transmission / reception point is (l1 / V) from the incident point O on the straight line connecting 6b and the incident point O.₁) V₂, The point Pb is at a distance apart by. Thus, an equivalent transmission / reception point changes depending on the position of the image reproduction point Q.
[0055]
Instead of the center P1 of the apparent transducer 73, the equivalent transmission / reception point shown above, that is, the equivalent transmission / reception point of the probe 7 is used as the center of the actual transducer 72 constituting the probe 7. In addition, as a path for ultrasonic waves to propagate from this equivalent transmission / reception point to the image reproduction point Q, from the equivalent transmission / reception point to the image reproduction point Q via the incident point O of the probe 7. The time required for the ultrasonic wave to propagate along the path is determined as the propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point Q. Based on the delay time, image reproduction was performed by experiment by applying to the signal processing procedure disclosed in International Publication No. WO 97/36175.
[0056]
The test conditions were the same as those shown in FIGS. 4 to 6 show reproduced images obtained by the method shown in the first embodiment. 4 to 6 correspond to FIGS. 13 to 15, respectively. In these drawings, white squares and arrows have the same meaning as in FIGS. In these image reproductions, for the sake of simplicity, the ultrasonic pulse transmitted from the probe 7 is directly irradiated on the defect 6, reflected by the defect 6, and directly reflected without being reflected by the bottom surface 4. , And received by the probe 7.
[0057]
Comparing FIG. 4 with FIG. 13, comparing FIG. 5 with FIG. 14, and further comparing FIG. 6 with FIG. 15, it is actually better to reproduce an image using the equivalent transmission / reception point according to the first embodiment. It can be seen that the image is reproduced near the position where the slits exist. As described above, when aperture synthetic signal processing is performed using the equivalent transmission / reception point shown in the first embodiment and the image of the defect 6 is reproduced, a clear reproduction image with higher accuracy can be obtained and the position of the position can be obtained. It can be seen that the effect of improving the estimation accuracy and the measurement accuracy can be obtained.
[0058]
In the first embodiment shown here, the case where the single probe method in which only one probe 7 is used for transmission / reception of ultrasonic waves is applied has been described, but transmission and reception are separately performed. Also in the case of applying the two-probe method using the probe 7, equivalent transmission points and reception points for each probe 7 are obtained in the same manner as in the first embodiment, and these equivalents are obtained. Applying the signal processing procedure shown in International Publication No. WO97 / 36175 using a transmission point and an equivalent reception pointAperture synthesis signal processingIf the image is reproduced by this, the effect of improving the estimation accuracy and measurement accuracy of the position of the defect 6 can be obtained as in the first embodiment. The same applies to a case where transmission is performed using a large number of probes 7 and reception is performed by a large number of probes 7.
[0059]
Further, in the case where separate probes 7 are used for transmission and reception, the refraction angle of the ultrasonic beam in transmission and the refraction angle of the ultrasonic beam in reception are different, even if they are the same angle. It doesn't matter. Further, the transmitting probe 7 and the receiving probe 7 may be the same type of probe 7 or different types of probes 7.
[0060]
Embodiment 2. FIG.
An ultrasonic flaw detector and an ultrasonic flaw detection method according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 7 is a diagram showing the operation of the ultrasonic flaw detector according to Embodiment 2 of the present invention.
[0061]
The configuration of the ultrasonic flaw detector according to Embodiment 2 is the same as that of Embodiment 1 shown in FIG. The second embodiment is different from the first embodiment in the handling of equivalent transmission / reception points and ultrasonic propagation delay times in the signal processing unit 84. This will be described with reference to FIG.
[0062]
In FIG. 7, a point Q is an image reproduction point, and a point P is the actual center of the vibrator 72. The thick solid line shown in the figure is a sound ray, and the point P and the point Q are connected to the surface 3 of the test body 1 so as to satisfy Snell's law of refraction. A point where the sound ray intersects the surface 3 is indicated by R.
[0063]
In the second embodiment, an equivalent transmission / reception point is set at the center P of the actual vibrator 72, and the ultrasonic propagation delay time τ between the equivalent transmission / reception point P and the image reproduction point Q is set as follows. It is given as shown in Equation 3. V₁And V₂Are the sound speeds of the ultrasonic waves in the wedge 71 and the test body 1, respectively. Also, l_RIs the distance between the actual center P of the vibrator 72 and the point R described above. L_RIs the distance between the point R and the image reproduction point Q.
[0064]
τ = l_R/ V₁+ L_R/ V₂                                  ... Formula 3
[0065]
The first term on the right side of Equation 3 is a propagation delay time caused by the propagation of the ultrasonic pulse from the center P of the actual transducer 72 to the point R. Further, the second term on the right side of Equation 3 is a propagation delay time caused by the propagation of the ultrasonic pulse at the point R to the image reproduction point Q.
[0066]
The propagation delay time is obtained by Equation 3, that is, the equivalent transmission / reception point of the probe 7 is taken as the center P of the actual transducer 72 constituting the probe 7, and image reproduction is performed from this equivalent transmission / reception point. As a path through which the ultrasonic wave propagates to the point Q, a path along a sound ray satisfying Snell's law of refraction is obtained, and the time required for the ultrasonic wave to propagate along the path is calculated from the equivalent transmission / reception point. The propagation delay time required for the ultrasonic wave to propagate to the image reproduction point Q is defined. Based on this propagation delay time, the image is experimentally applied to the signal processing procedure disclosed in International Publication No. WO 97/36175. I tried to play it.
[0067]
The test conditions were the same as those shown in FIGS. 8 to 10 show reproduced images obtained by the method shown in the second embodiment. 8 to 10 correspond to FIGS. 13 to 15, respectively. In these drawings, white squares and arrows have the same meaning as in FIGS. In these image reproductions, for the sake of simplicity, the ultrasonic pulse transmitted from the probe 7 is directly irradiated on the defect 6, reflected by the defect 6, and directly reflected without being reflected by the bottom surface 4. , And received by the probe 7.
[0068]
FIG. 8 is compared with FIG. 13, FIG. 9 is compared with FIG. 14, and FIG. 10 is compared with FIG. 15, and image reproduction is performed using the equivalent transmission / reception point and propagation delay time according to the second embodiment. It can be seen that the image is reproduced near the position where the actual slit exists. As described above, when the aperture synthetic signal processing is performed using the equivalent transmission / reception point and the propagation delay time shown in the second embodiment and the image of the defect 6 is reproduced, a more accurate and clear reproduced image is obtained. It can be seen that the effect of improving the position estimation accuracy and the measurement accuracy can be obtained.
[0069]
Further, comparing FIG. 8 with FIG. 4, comparing FIG. 9 with FIG. 5, and further comparing FIG. 10 with FIG. 6, the image reproduced according to the second embodiment and the reproduction according to the first embodiment. It can be seen that almost the same reproduced image is obtained under these test conditions.
[0070]
In the second embodiment shown here, the case where the single probe method in which only one probe 7 is used for transmission / reception of ultrasonic waves is applied has been described, but transmission and reception are separately performed. Even when the two-probe method using the probe 7 is applied, the same transmission point and reception point are taken for each probe 7 as in the second embodiment, and it is equivalent to the image reproduction point. The propagation delay time with respect to a typical transmission point is obtained in the same manner as in the second embodiment, and the propagation delay time between the image reproduction point and an equivalent reception point is obtained in the same manner as in the second embodiment. By using the delay time and applying the signal processing procedure disclosed in International Publication No. WO 97/36175 to reproduce an image by aperture synthesis signal processing, the position of the defect 6 can be determined as in the second embodiment. The effect of improving estimation accuracy and measurement accuracy is obtained. . The same applies to a case where transmission is performed using a large number of probes 7 and reception is performed by a large number of probes 7.
[0071]
Further, in the case where separate probes 7 are used for transmission and reception, the refraction angle of the ultrasonic beam in transmission and the refraction angle of the ultrasonic beam in reception are different, even if they are the same angle. It doesn't matter. Further, the transmitting probe 7 and the receiving probe 7 may be the same type of probe 7 or different types of probes 7.
[0072]
In the first and second embodiments, the probe 7 and the test body 1 are in contact with each other through an acoustic coupling medium layer that is very thin compared to the wavelength, that is, the so-called direct contact method. The case where the method called is used was demonstrated. In this case, the influence of the acoustic coupling medium layer is virtually negligible. In the case where there is a relatively thick acoustic coupling medium layer such as a water film as an acoustic coupling medium between the probe 7 and the test body 1, it can be implemented by determining the propagation delay time of the ultrasonic wave as follows. The same operations and effects as those described in the first and second embodiments are obtained.
[0073]
That is, in the case of the above-described first embodiment, the equivalent transmission / reception point of the probe 7 is set at the center P of the actual vibrator 72 constituting the probe 7. As a path through which the ultrasonic wave propagates from this equivalent transmission / reception point to the image reproduction point Q, the next path is obtained. First, consider a path that emanates from the equivalent transmission / reception point and reaches the incident point O of the probe 7 along a straight line. The sound ray along this path enters the boundary surface between the wedge 71 and the acoustic coupling medium layer from the wedge 71 side at the incident point O. At this time, the sound ray is refracted and propagated in the layer of the acoustic coupling medium at the incident point O according to Snell's law of refraction. This refraction-propagating sound ray also propagates in the layer of the acoustic coupling medium along a straight line.
[0074]
Next, the sound ray enters the boundary surface between the acoustic coupling medium layer and the surface 3 of the test body 1 from the acoustic coupling medium layer side. Let S be the point where this incident sound ray intersects the boundary surface between the layer of the acoustic coupling medium and the surface 3 of the specimen 1. Finally, consider a path along a straight line connecting the point S and the image reproduction point Q. As described above, it was possible to determine one path from the equivalent transmission / reception point, passing through the incident point O, and then passing through the point S to the image reproduction point Q. The transmission / reception time required for the ultrasonic wave to propagate along the path determined as described above from the transmission / reception point of the probe 7 to the image reproduction point Q from the transmission / reception point is obtained. If the signal processing related to image reproduction is executed in the same manner as in the first embodiment, the same operation and effect as in the first embodiment can be obtained.
[0075]
In the case of the second embodiment, the equivalent transmission / reception point of the probe 7 is set at the center P of the actual transducer 72 constituting the probe 7. As a path through which the ultrasonic wave propagates from this equivalent transmission / reception point to the image reproduction point Q, the next path is obtained. That is, considering the sound ray from the equivalent transmission / reception point to the image reproduction point Q, the sound ray passes through two different boundary surfaces. One is a boundary surface between the wedge 71 and the acoustic coupling medium layer, and the other is a boundary surface between the layer of the acoustic coupling medium and the surface 3 of the specimen 1. The sound ray passes through these two boundary surfaces, and is emitted from the equivalent transmission / reception point on the condition that the Snell's law of refraction is satisfied at each of the two boundary surfaces, and reaches the image reproduction point Q. Find the route to go. This route is fixed to one. Obtain the transmission / reception point of the probe 7 described above and the propagation delay time required for the ultrasonic wave to propagate from the transmission / reception point to the image reproduction point Q along the path determined as described above. If signal processing related to image reproduction is executed in the same manner as in the second embodiment, the same actions and effects as in the second embodiment can be obtained.
[0076]
【The invention's effect】
As described above, the ultrasonic flaw detection apparatus according to the present invention includes a wedge and a vibrator, and is driven by a transmission signal to transmit an ultrasonic pulse obliquely with respect to the flaw detection surface of the test specimen. A probe for receiving the ultrasonic pulse reflected by the acoustic discontinuity as an echo, and moving the probe over a predetermined scanning range of the specimen, and a spatial position of the probe And a scanning mechanism unit that outputs and outputs the transmission signal to the probe, and inputs and stores the echo received from the probe and receives the echo from the scanning mechanism unit The spatial position of the probe is input and stored, and a transmission / reception point equivalent to the ultrasonic transmission / reception surface of the probe is taken as the center of the actual transducer, and the equivalent transmission / reception point FromOpenAs a path through which the ultrasonic wave propagates to the image reproduction point, which is a point for obtaining the acoustic discontinuity as an image by mouth synthesis signal processing, the equivalent transmission / reception point through the probe incident point is used as the path. A path to the image reproduction point is obtained, and a time required for the ultrasonic wave to propagate along the path is a propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point. None, the distance from the center of the actual vibrator to the incident point is l₁, L is the distance from the incident point to the image reproduction point, and V is the sound velocity of the ultrasonic wave at the wedge.₁, The sound velocity of the ultrasonic wave in the specimen is V₂Then, the propagation delay time τThe,formulaτ = l₁/ V₁+ L / V₂ Calculate fromA transmission / reception device that reproduces an image of the acoustic discontinuity portion by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe. As a result, a clear reproduced image with higher accuracy can be obtained, and the defect position estimation accuracy and measurement accuracy can be improved.
[0077]
As described above, the ultrasonic flaw detection apparatus according to the present invention includes a wedge and a vibrator, and is driven by a transmission signal to transmit an ultrasonic pulse obliquely with respect to the flaw detection surface of the test specimen. A probe for receiving the ultrasonic pulse reflected by the acoustic discontinuity as an echo, and moving the probe over a predetermined scanning range of the specimen, and a spatial position of the probe And a scanning mechanism unit that outputs and outputs the transmission signal to the probe, and inputs and stores the echo received from the probe and receives the echo from the scanning mechanism unit The spatial position of the probe is input and stored, and a transmission / reception point equivalent to the ultrasonic transmission / reception surface of the probe is taken as the center of the actual transducer, and the equivalent transmission / reception point FromOpenA path along the sound ray that satisfies Snell's refraction law is obtained as a path through which the ultrasonic wave propagates to the image reproduction point, which is a point for obtaining the acoustic discontinuity as an image by mouth synthesis signal processing. The time required for the ultrasonic wave to propagate along the transmission line is defined as a propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point. Is the distance to the intersection where the surface intersects the surface of the specimen_R, The distance from the intersection to the image reproduction point is L_R, The sound velocity of the ultrasonic wave in the wedge is V₁, The sound velocity of the ultrasonic wave in the specimen is V₂Then, the propagation delay time τThe,formulaτ = l_R/ V₁+ L_R/ V₂ Calculate fromA transmission / reception device that reproduces an image of the acoustic discontinuity portion by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe. As a result, a clear reproduced image with higher accuracy can be obtained, and the defect position estimation accuracy and measurement accuracy can be improved.
[0078]
In addition, as described above, the ultrasonic flaw detection apparatus according to the present invention transmits the ultrasonic pulse at a transmission angle inclined with respect to the flaw detection surface of the test body driven by the transmission signal, as described above. Since the ultrasonic pulse reflected by the acoustic discontinuity in the test body is received as an echo at an angle of reception different from the transmission angle with respect to the flaw detection surface, a more accurate and clear reproduced image can be obtained. As a result, the defect position estimation accuracy and measurement accuracy are improved.
[0079]
Further, in the ultrasonic flaw detection apparatus according to the present invention, as described above, the probe is driven by a transmission signal and transmits an ultrasonic pulse at a transmission angle inclined with respect to the flaw detection surface of the specimen, and Since the ultrasonic pulse reflected by the acoustic discontinuity in the specimen is received as an echo at a reception angle that is the same as the transmission angle with respect to the flaw detection surface, a clear reproduction image with higher accuracy can be obtained. As a result, the defect position estimation accuracy and measurement accuracy are improved.
[0080]
In the ultrasonic flaw detection method according to the present invention, as described above, the scanning mechanism unit moves the probe composed of the wedge and the transducer over the predetermined scanning range of the test body, and generates a transmission signal. And transmitting to the probe, and transmitting the ultrasonic pulse obliquely with respect to the flaw detection surface of the specimen by the probe, and acoustic discontinuity in the specimen by the probe. A reception step of receiving the ultrasonic pulse reflected by the unit as an echo; and the probe when the echo received from the probe is input and stored and the echo is stored from the scanning mechanism unit A storage step for inputting and storing the spatial position of the child, and a transmission / reception point equivalent to the ultrasonic transmission / reception surface of the probe is taken at the center of the actual transducer, and from the equivalent transmission / reception pointOpenAs a path through which the ultrasonic wave propagates to the image reproduction point, which is a point for obtaining the acoustic discontinuity as an image by mouth synthesis signal processing, the equivalent transmission / reception point through the probe incident point is used as the path. A path to the image reproduction point is obtained, and a time required for the ultrasonic wave to propagate along the path is a propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point. None, the distance from the center of the actual vibrator to the incident point is l₁, L is the distance from the incident point to the image reproduction point, and V is the sound velocity of the ultrasonic wave at the wedge.₁, The sound velocity of the ultrasonic wave in the specimen is V₂Then, the propagation delay time τThe,formulaτ = l₁/ V₁+ L / V₂ Calculate fromAnd a signal processing step of reproducing an image of the acoustic discontinuity portion by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe. As a result, a clear reproduced image with higher accuracy can be obtained, and the defect position estimation accuracy and measurement accuracy can be improved.
[0081]
In the ultrasonic flaw detection method according to the present invention, as described above, the scanning mechanism unit moves the probe composed of the wedge and the transducer over the predetermined scanning range of the test body, and generates a transmission signal. And transmitting to the probe, and transmitting the ultrasonic pulse obliquely with respect to the flaw detection surface of the specimen by the probe, and acoustic discontinuity in the specimen by the probe. A reception step of receiving the ultrasonic pulse reflected by the unit as an echo; and the probe when the echo received from the probe is input and stored and the echo is stored from the scanning mechanism unit A storage step for inputting and storing the spatial position of the child, and a transmission / reception point equivalent to the ultrasonic transmission / reception surface of the probe is taken at the center of the actual transducer, and from the equivalent transmission / reception pointOpenA path along the sound ray that satisfies Snell's refraction law is obtained as a path through which the ultrasonic wave propagates to the image reproduction point, which is a point for obtaining the acoustic discontinuity as an image by mouth synthesis signal processing. The time required for the ultrasonic wave to propagate along the transmission line is defined as a propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point. Is the distance to the intersection where the surface intersects the surface of the specimen_R, The distance from the intersection to the image reproduction point is L_R, The sound velocity of the ultrasonic wave in the wedge is V₁, The sound velocity of the ultrasonic wave in the specimen is V₂Then, the propagation delay time τThe,formulaτ = l_R/ V₁+ L_R/ V₂ Calculate fromAnd a signal processing step of reproducing an image of the acoustic discontinuity portion by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe. As a result, a clear reproduced image with higher accuracy can be obtained, and the defect position estimation accuracy and measurement accuracy can be improved.
[0082]
In the ultrasonic flaw detection method according to the present invention, as described above, in the transmission step, a transmission signal is generated and output to the probe, and an ultrasonic pulse is detected by the probe. Transmitting at a transmission angle inclined with respect to a surface, and in the reception step, the ultrasonic pulse reflected by an acoustic discontinuity in the specimen by the probe is transmitted with respect to the flaw detection surface. Since it is received as an echo at an inclined reception angle different from the above, a clear reproduction image with higher accuracy can be obtained, and the defect position estimation accuracy and measurement accuracy can be improved.
[0083]
Furthermore, in the ultrasonic flaw detection method according to the present invention, as described above, the transmission step generates a transmission signal and outputs the transmission signal to the probe, and the ultrasonic pulse is detected by the probe. Transmitting at a transmission angle inclined with respect to a surface, and in the reception step, the ultrasonic pulse reflected by an acoustic discontinuity in the specimen by the probe is transmitted with respect to the flaw detection surface. Therefore, a clear reproduced image with higher accuracy can be obtained, and the defect position estimation accuracy and measurement accuracy can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an ultrasonic flaw detector according to Embodiment 1 of the present invention.
FIG. 2 is a diagram showing an operation of the ultrasonic flaw detector according to Embodiment 1 of the present invention.
FIG. 3 is a diagram showing an operation of the ultrasonic flaw detector according to Embodiment 1 of the present invention.
FIG. 4 is a diagram showing an operation of the ultrasonic flaw detector according to Embodiment 1 of the present invention.
FIG. 5 is a diagram showing the operation of the ultrasonic flaw detector according to Embodiment 1 of the present invention.
FIG. 6 is a diagram showing an operation of the ultrasonic flaw detector according to Embodiment 1 of the present invention.
FIG. 7 is a diagram showing an operation of an ultrasonic flaw detector according to Embodiment 2 of the present invention.
FIG. 8 is a diagram showing an operation of an ultrasonic flaw detector according to Embodiment 2 of the present invention.
FIG. 9 is a diagram showing the operation of the ultrasonic flaw detector according to Embodiment 2 of the present invention.
FIG. 10 is a diagram showing the operation of the ultrasonic flaw detector according to Embodiment 2 of the present invention.
FIG. 11 is a diagram showing the operation of a conventional ultrasonic flaw detector.
FIG. 12 is a diagram showing the operation of a conventional ultrasonic flaw detector.
FIG. 13 is a diagram showing the operation of a conventional ultrasonic flaw detector.
FIG. 14 is a diagram showing the operation of a conventional ultrasonic flaw detector.
FIG. 15 is a diagram showing the operation of a conventional ultrasonic flaw detector.
[Explanation of symbols]
1 test body, 2 base material part, 3 surface of test body 1, 4 bottom surface of test body 1, 5 weld, 6 defect, 7 probe, 71 wedge, 72 actual vibrator, 73 apparent vibrator, 8, 9, 10 slit, 80 transmission / reception device, 81 control unit, 82 transmission unit, 83 reception unit, 84 signal processing unit, 85 position detection unit, 90 scanning mechanism unit.

Claims (8)

It is composed of a wedge and a vibrator, and is driven by a transmission signal to transmit an ultrasonic pulse obliquely with respect to the flaw detection surface of the test specimen, and the ultrasonic pulse reflected by the acoustic discontinuity in the test specimen A probe to receive as an echo,
A scanning mechanism for moving the probe over a predetermined scanning range of the specimen and outputting a spatial position of the probe;
Generate the transmission signal and output to the probe,
Input and store the echo received from the probe, and input and store the spatial position of the probe when the echo is received from the scanning mechanism unit,
The ultrasonic transmitting and receiving surface and equivalent transceiver points of the probe are taken up in the center of the actual in the transducer, from the equivalent transceiver point, the acoustic discontinuity as an image by apertures combined signal processing As a path through which the ultrasonic wave propagates to the image reproduction point, which is a point to be obtained, a path from the equivalent transmission / reception point to the image reproduction point via the incident point of the probe is obtained, and along the path The time required for the ultrasonic wave to propagate is the propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point,
The distance from the center of the actual vibrator to the incident point is l ₁ , the distance from the incident point to the image reproduction point is L, the sound velocity of the ultrasonic wave at the wedge is V ₁ , and the ultrasonic wave velocity at the test body is If the speed of sound is V ₂ , the propagation delay time τ is
Calculated from the formula τ = l ₁ / V ₁ + L / V ₂ ,
A transmission / reception device that reproduces an image of the acoustic discontinuity by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe. A featured ultrasonic flaw detector. It is composed of a wedge and a vibrator, and is driven by a transmission signal to transmit an ultrasonic pulse obliquely with respect to the flaw detection surface of the test specimen, and the ultrasonic pulse reflected by the acoustic discontinuity in the test specimen A probe to receive as an echo,
A scanning mechanism for moving the probe over a predetermined scanning range of the specimen and outputting a spatial position of the probe;
Generate the transmission signal and output to the probe,
Input and store the echo received from the probe, and input and store the spatial position of the probe when the echo is received from the scanning mechanism unit,
The ultrasonic transmitting and receiving surface and equivalent transceiver points of the probe are taken up in the center of the actual in the transducer, from the equivalent transceiver point, the acoustic discontinuity as an image by apertures combined signal processing A path along which the ultrasonic wave propagates to Snell's refraction law is obtained as a path through which the ultrasonic wave propagates to the image reproduction point, and the time required for the ultrasonic wave to propagate along the path is calculated as follows. No propagation delay time required for ultrasonic waves to propagate from an equivalent transmission / reception point to the image reproduction point,
The distance from the center of the actual transducer to the intersection where the sound ray intersects the surface of the specimen is l _R , the distance from the intersection to the image reproduction point is L _R , and the ultrasonic sound velocity at the wedge is V ₁ , where the velocity of ultrasonic waves in the specimen is V ₂ , the propagation delay time τ is
Calculated from the formula τ = l _R / V ₁ + L _R / V ₂ ,
A transmission / reception device that reproduces an image of the acoustic discontinuity by a direct method in the aperture synthetic signal processing based on the propagation delay time, the echo, and the spatial position of the probe. A featured ultrasonic flaw detector. The probe is driven by a transmission signal to transmit an ultrasonic pulse at a transmission angle inclined with respect to a flaw detection surface of the test specimen, and the ultrasonic pulse reflected by an acoustic discontinuity in the test specimen. The ultrasonic flaw detector according to claim 1, wherein the ultrasonic flaw detector is received as an echo at a reception angle that is different from the transmission angle with respect to the flaw detection surface. The probe is driven by a transmission signal to transmit an ultrasonic pulse at a transmission angle inclined with respect to a flaw detection surface of the test specimen, and the ultrasonic pulse reflected by an acoustic discontinuity in the test specimen. The ultrasonic flaw detector according to claim 1, wherein the ultrasonic flaw detector is received as an echo at a reception angle inclined with respect to the flaw detection surface as the transmission angle. A moving step of moving a probe composed of a wedge and a transducer over a predetermined scanning range of the specimen by the scanning mechanism;
A transmission step of generating a transmission signal and outputting it to the probe, and transmitting an ultrasonic pulse obliquely with respect to the flaw detection surface of the specimen by the probe;
A receiving step of receiving, as an echo, the ultrasonic pulse reflected by an acoustic discontinuity in the specimen by the probe;
A storage step of inputting and storing the echo received from the probe and inputting and storing a spatial position of the probe when the echo is stored from the scanning mechanism unit;
The ultrasonic transmitting and receiving surface and equivalent transceiver points of the probe are taken up in the center of the actual in the transducer, from the equivalent transceiver point, the acoustic discontinuity as an image by apertures combined signal processing A path from which the ultrasonic wave propagates to the image reproduction point, which is a point to be obtained, is obtained from the equivalent transmission / reception point to the image reproduction point via the incident point of the probe, and along the path The time required for the ultrasonic wave to propagate is the propagation delay time required for the ultrasonic wave to propagate from the equivalent transmission / reception point to the image reproduction point, and from the center of the actual transducer to the incident point. , L _{1 is} the distance from the incident point to the image reproduction point, V _{1 is} the sound velocity of the ultrasonic wave at the wedge, and V ₂ is the sound velocity of the ultrasonic wave at the specimen. a total of from equation _{τ = l 1 / V 1 +} L / V 2 And, the propagation delay time, the echo, and on the basis of the spatial position of the probe, the direct method in the aperture synthesis signal processing, and a signal processing step of reproducing the image of the acoustic discontinuities An ultrasonic flaw detection method characterized by the above. A moving step of moving a probe composed of a wedge and a transducer over a predetermined scanning range of the specimen by the scanning mechanism;
A transmission step of generating a transmission signal and outputting it to the probe, and transmitting an ultrasonic pulse obliquely with respect to the flaw detection surface of the specimen by the probe;
A receiving step of receiving, as an echo, the ultrasonic pulse reflected by an acoustic discontinuity in the specimen by the probe;
A storage step of inputting and storing the echo received from the probe and inputting and storing a spatial position of the probe when the echo is stored from the scanning mechanism unit;
The ultrasonic transmitting and receiving surface and equivalent transceiver points of the probe are taken up in the center of the actual in the transducer, from the equivalent transceiver point, the acoustic discontinuity as an image by apertures combined signal processing A path along which the ultrasonic wave propagates to Snell's refraction law is obtained as a path through which the ultrasonic wave propagates to the image reproduction point, and the time required for the ultrasonic wave to propagate along the path is calculated as follows. This is the propagation delay time required for ultrasonic waves to propagate from the equivalent transmission / reception point to the image reproduction point, and the distance from the center of the actual transducer to the intersection where the sound ray intersects the surface of the specimen is l. _{When R 1 is} the distance from the intersection to the image reproduction point L _R , the ultrasonic sound velocity at the wedge is V ₁ , and the ultrasonic sound velocity at the specimen is V ₂ , the propagation delay time τ is expressed by the equation τ from _{= l R / V 1 + L} R / V 2 meter And, the propagation delay time, the echo, and on the basis of the spatial position of the probe, the direct method in the aperture synthesis signal processing, and a signal processing step of reproducing the image of the acoustic discontinuities An ultrasonic flaw detection method characterized by the above. In the transmission step, a transmission signal is generated and output to the probe, and an ultrasonic pulse is transmitted by the probe at a transmission angle inclined with respect to a flaw detection surface of the test body,
In the receiving step, the ultrasonic pulse reflected by the probe by an acoustic discontinuity in the specimen is received as an echo at an angle of reception different from the transmission angle with respect to the flaw detection surface. The ultrasonic flaw detection method according to claim 5 or 6. In the transmission step, a transmission signal is generated and output to the probe, and an ultrasonic pulse is transmitted by the probe at a transmission angle inclined with respect to a flaw detection surface of the test body,
In the receiving step, the ultrasonic pulse reflected by an acoustic discontinuity in the specimen by the probe is received as an echo at a reception angle that is inclined with respect to the flaw detection surface as the transmission angle. The ultrasonic flaw detection method according to claim 5 or 6.

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