JP2018119848A - Ultrasonic flaw detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic flaw detector with which, of a simple structure though, it is possible to perform highly accurate ultrasonic flaw detection.SOLUTION: An ultrasonic flaw detector 10 comprises an array probe 19a and a control unit 110. The array probe 19a transmits an ultrasonic wave toward a test piece 30. The control unit 110 causes a plurality of position detection scanlines for detecting the position of the test piece 30 to be transmitted as an ultrasonic wave by the array probe 19a. The control unit 110 causes each of the position detection scanlines reflected on the surface of the test piece 30 to be received by the array probe 19a. The control unit 110 thereby calculates the point-to-point distance between the known transmitted position of each position detection scanline and the reflection position on the surface of the test piece 30. The control unit 110 determines the test piece position of the test piece 30 relative to the array probe 19a on the basis of a plurality of transmitted positions and the point-to-point distance corresponding to the transmitted positions, and determines, in accordance with the test piece position, the transmit/receive conditions of flaw detection scanlines for flaw detection that are transmitted/received by the array probe 19a.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an ultrasonic flaw detector using an array probe.

  Claim 1 of Patent Document 1 states that “a first array probe and a second array probe among a plurality of array probes irradiate ultrasonic beams orthogonal to each other, and Based on the eccentricity of the specimen based on the first distance calculated using the reflected wave echo of the ultrasonic beam irradiated by the array probe, the excitation condition of the second array probe is determined. In other words, the first array probe performs irradiation by changing the direction of the ultrasonic beam, and the first array probe calculated using the reflected wave echo of the ultrasonic beam irradiated by the second array probe. Based on the amount of eccentricity of the test body based on the distance, the ultrasonic wave is irradiated by changing the excitation condition of the first array probe and changing the direction of the ultrasonic beam of the first array probe. "Automatic flaw detector" is described.

Japanese Patent No. 54644949

In the case of Patent Document 1, it is necessary to arrange each array probe with high accuracy. For example, there is a problem that the relative displacement between the array probes affects the flaw detection.
In the case of Patent Document 1, the transmission condition of the other array probe is corrected using the measurement result of one array probe. For this reason, in Patent Document 1, as shown in FIG. 3, each array probe is offset with respect to the transport direction of the specimen, so that one array probe and the other in the traveling direction of the specimen. When the specimen is bent with the array probe, there is a problem that the correction amount is affected by the bending and the correction accuracy may be lowered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic flaw detection apparatus capable of performing high-accuracy ultrasonic flaw detection with a simple configuration.

The ultrasonic flaw detector of the present invention is
An array probe that transmits and receives ultrasonic waves toward a test body having a longitudinal shape and conveyed in the longitudinal direction;
A plurality of position detection scanning lines for detecting the position of the test body are transmitted to the array probe as the ultrasonic wave, and each position detection scanning line reflected on the surface of the test body is transmitted to the array probe. By calculating the distance between two points between the known transmission position of each of the position detection scanning lines and the reflection position of the surface of the specimen,
Based on a plurality of the transmission positions and the distance between the two points corresponding to each of the transmission positions, determine a specimen position indicating the position of the specimen relative to the array probe;
A control unit that determines transmission / reception conditions indicating transmission conditions and reception conditions of a flaw detection scanning line that is the ultrasonic wave for flaw detection transmitted and received by the array probe according to the determined position of the specimen.

  According to the present invention, it is possible to provide an ultrasonic flaw detection apparatus capable of performing high-accuracy ultrasonic flaw detection with a simple configuration.

FIG. 3 is a side view showing the positional relationship between the test body and the array probe in the first embodiment. FIG. 3 is a diagram illustrating the hardware configuration of the ultrasonic flaw detector according to the first embodiment. FIG. 3 is a diagram of the first embodiment and shows a vertical scanning line. FIG. 3 is a diagram illustrating the oblique scanning line in the first embodiment. FIG. 3 is a diagram of the first embodiment and shows a relationship between scans and steps in a flaw detection process. FIG. 3 is a flowchart of the operation of the control unit in the first embodiment. FIG. 3 is a diagram of the first embodiment, and shows distance detection with a round bar by position detection scanning lines. FIG. 4 is another diagram showing detection of a round bar position by the position detection scanning line in the diagram of the first embodiment. FIG. 5 is a diagram of the first embodiment, and shows a detection result by a position detection scanning line. FIG. 5 is a diagram of the first embodiment, showing a relationship between a step of detecting a correction amount and other steps. FIG. 5 is a diagram of the first embodiment, and shows a step of obtaining a round bar position from a detection result by a position detection scanning line. The figure of Embodiment 1 is a figure which shows the misalignment amount table. The figure of Embodiment 1 is a figure which illustrates typically the case where a control part calculates | requires transmission / reception conditions by calculation. The figure of Embodiment 1 is a figure which shows a transmission / reception condition table. The figure of Embodiment 1 is a figure explaining the case where a control part calculates | requires misalignment amount by calculation. FIG. 5 is another diagram for explaining the case where the control unit obtains the misalignment amount by calculation in the diagram of the first embodiment. The figure of Embodiment 1 is a figure which shows the case where a test body is a square. FIG. 3 is a diagram of the first embodiment, and is a diagram illustrating distance detection with a square member using a position detection scanning line.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the part which is the same or it corresponds in each figure. In the description of the embodiments, the description of the same or corresponding parts will be omitted or simplified as appropriate.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a positional relationship between the test body 30 and the array probe 19a and the like. The left side of FIG. 2 shows the X direction arrow view of the array probe 19a and the like and the test body 30 viewed from the X direction of FIG. 1, and the right side of FIG. 2 shows the hardware configuration of the ultrasonic flaw detector 10. 1 corresponds to a side view, and the left side of FIG. 2 corresponds to a front view. As shown in FIG. 2, the plurality of array probes 19 a and the like are arranged around the test body 30. The plurality of array probes 19a and the like emit ultrasonic beams (scanning lines). In FIG. 1, the array probes 19b and 19d are omitted.

  As shown in FIG. 1, the test body 30 has a longitudinal shape and is conveyed in the longitudinal direction. The test body 30 is, for example, a circular rod-shaped body or a quadrangular columnar body with a cross section having a longitudinal direction as a normal direction. The conveyance direction 41 is the longitudinal direction of the test body 30. The array probes 19a to 19d are installed in a probe holder 25 fixed to a gantry 40 that supports a structure. The gantry 40 may be filled with water or the like for the purpose of promoting the transmission of ultrasonic waves.

*** Explanation of configuration ***
As shown in FIG. 2, the plurality of array probes 19 a and the like are arranged around the test body 30. The ultrasonic flaw detector 10 includes a processor 11, a main storage device 12, an auxiliary storage device 13, a transmission / reception unit 14, and array probes 19a, 19b, 19c, and 19d as hardware configurations. The processor 11, the main storage device 12, the auxiliary storage device 13, and the transmission / reception unit 14 are connected by a bus 15.

  The array probe 19 a and the like are connected to the transmission / reception unit 14 by a signal line 18. The array probe 19 a and the like transmit and receive ultrasonic waves toward the test body 30. That is, the array probe 19a transmits an ultrasonic wave toward the test body 30, and receives a reflected wave reflected by the test body 30 among the ultrasonic waves transmitted by the user. The array probes 19b, 19c, and 19d are the same as the array probe 19a. The array probe 19a and the like have a plurality of transducers. The transmission / reception unit 14 transmits / receives an ultrasonic beam (also referred to as a scanning line or simply a beam) via the array probe 19a or the like.

  The ultrasonic flaw detector 10 includes a control unit 110 and an alarm unit 111 as functional elements. A program for realizing the control unit 110 and the alarm unit 111 is stored in the auxiliary storage device 13, and this program is read into the main storage device 12 by the processor 11, and the processor 11 reads out from the main storage device 12 and executes it. Thus, the functions of the control unit 110 and the alarm unit 111 are realized.

The control unit 110 controls the ultrasonic beam. The control unit 110 determines the reference position of the test object and the plurality of array probes from the measurement result of the reflection time of the ultrasonic beam oscillated from each transducer (element) such as the array probe 19a. The relative position deviation with respect to the probe is calculated, and the correction is automatically performed so that the irradiation direction of the ultrasonic beam to be irradiated next by the array probe becomes the specimen reference position.
The control unit 110 transmits a plurality of position detection scanning lines (described later in step S11) for detecting the position of the test object as ultrasonic waves to the array probe and reflects each position detection scan reflected on the surface of the test object. By causing the array probe to receive the line, the distance between two points between the known transmission position of each position detection scanning line and the reflection position of the surface of the specimen is calculated. Then, the control unit 110 determines a test body position indicating the position of the test body with respect to the array probe based on the plurality of transmission positions and the distance between the two points corresponding to each transmission position. The control unit 110 determines transmission / reception conditions indicating transmission conditions and reception conditions for the flaw detection scanning lines, which are ultrasonic waves for flaw detection transmitted / received by the array probe, in accordance with the determined specimen position.

*** Explanation of operation ***
With reference to FIGS. 3 to 17, calculation of the misalignment amount of the test body 30 and the correction method for the transmission / reception conditions of the flaw detection scanning line by the control unit 110 of the ultrasonic flaw detection apparatus 10 will be described. In the array probe, one scanning line is formed in accordance with selection of transmission / reception elements and various transmission / reception settings by the control unit 110. In accordance with the specified flaw detection method, flaw detection scanning lines such as the vertical scanning line shown in FIG. 3 used for vertical flaw detection and the oblique scanning line shown in FIG. 4 used for oblique flaw detection are detected from the array probe. It is transmitted and ultrasonic flaw detection is performed.
FIG. 5 is a diagram illustrating the relationship between scanning and steps. In the present embodiment, one scan refers to one cycle in which a plurality of scanning lines are sequentially transmitted in one array probe. FIG. 5 shows an example in which the scanning line A → the scanning line B → the scanning line C → the scanning line D is completed. The contents of the scanning line A and the scanning line B are the flaw detection scanning line 1 and the flaw detection scanning line 2, respectively. The contents of the scanning line C and the scanning line D are respectively the flaw detection scanning line 3 and the position detection scanning line X. , A position detection scanning line Y. The next one scan is the next one scan, and the next one scan is a cycle of scanning line A → scanning line B → scanning line C → scanning line D. In this way, a round of scanning lines (scanning line A to scanning line D) is referred to as scanning, and flaw detection by each scanning line during scanning is referred to as a step. 5 includes a step <3> for transmitting both the flaw detection scanning line 3 and the position detection scanning line X and a step <4> for transmitting only the position detection scanning line Y as described above. One scan may include both a step of transmitting both the flaw detection scanning line and the position detection scanning line and a step of transmitting only the position detection scanning line, or only one of them exists. Also good. When both the flaw detection scanning line 3 and the position detection scanning line X are transmitted as in step <3>, the element that generates the flaw detection scanning line 3 is usually used as the element used for the position detection scanning line X. do not do.
As in the example of FIG. 5, step <1> is a step of generating one flaw detection scanning line 1 by controlling transmission of 20 elements 1 to 20. Step <2> is a step of generating one flaw detection scanning line 2 by controlling transmission of the elements 21 to 40. Step <3> is a process of generating one flaw detection scanning line 3 by controlling transmission of the elements 41 to 60 and generating one position detection scanning line X by controlling transmission of the element 20. It is. Step <4> is a step of generating one position detection scanning line Y by controlling transmission of the element d.

A method of calculating the misalignment amount executed by the control unit 110 in the present embodiment will be described. The process flow will be described with reference to the flowchart of FIG.
(1) The control unit 110 corrects the transmission / reception conditions of each array probe independently of the other array probes. For this reason, in the following description, the array probe is referred to as an array probe 19a. The description of the array probe 19a also applies to the array probes 19b to 19d.
(2) In the following description, the specimen 30 is a round bar 31 unless otherwise specified.
(3) The main body of the operation in FIG. In addition, transmission / reception of an ultrasonic wave is performed by the control unit 110 via the transmission / reception unit 14 and the array probe 19a.

<Step S11>
In the ultrasonic flaw detector 10, a position detection scan line for specifying the relative positional relationship between the array probe 19 a and the round bar 31 is used in addition to the flaw detection scan lines for performing various vertical and oblique flaw detection flaws. As described in the explanation of FIG. 5, the position detection scanning line is transmitted / received at the step of the flaw detection scanning line during one scan, or is transmitted / received at the single step of the position scanning line. Regarding the position detection scan line, the control unit 110 adjusts the element for transmitting and receiving the position detection scan line and the transmission / reception timing of the position detection scan line so that they do not affect each other ultrasonically with the flaw detection scan line. Then, the control unit 110 transmits and receives position detection scanning lines independently of the flaw detection scanning lines. In the present embodiment, the control unit 110 transmits / receives the position detection scanning line with only one element, but is not limited thereto.

<Step S12>
As shown in FIG. 7, from the material surface echo (position detection scanning line ED) obtained by the position detection scanning line, the position of the excited element (transmission position) and the presence or absence of the misalignment amount of the round bar 31 are obtained. The propagation time corresponding to the path equal to the line segment between the element and the material surface on the straight line connecting the centers of the round bars 31 is obtained. This is because when the element is vibrated, the ultrasonic wave propagates as a spherical wave with a wide directivity. As a result, the component passing through the center of the round bar 31 has the shortest propagation time.
On the other hand, a flaw detection scanning line used for flaw detection is generated by simultaneously driving a plurality of elements. In this case, the flaw detection scanning line has a narrow directivity. The directivity angle is obtained by the following formula.
Directional angle = Kλ / D
K: Directional angle coefficient
λ: wavelength.
D: Element dimensions.
From the above propagation time, the distance between the element and the surface of the round bar 31 on the straight line connecting the element position (transmission position) and the center of the round bar 31 is known.

The present embodiment is characterized in that the transmission / reception condition of the flaw detection scanning line is corrected for one array probe.
8 and 9 are diagrams showing detection of misalignment of the round bar 31 with respect to one array probe. The result of FIG. 9 is acquired by using a plurality (n) of position detection scanning lines as shown in FIG. 8 for one array probe. FIG. 9A shows a case where the round bar 31 is not misaligned, and FIG. 9B shows a case where the round bar 31 is misaligned. 9A and 9B, the horizontal axis indicates the position detection scanning line, and the vertical axis indicates the distance between the element position (transmission position) for transmitting and receiving the position detection scanning line and the reflection position at the round bar 31. Indicates. From the result of FIG. 9, the relative position (center misalignment) of the round bar 31 with respect to one array probe can be obtained by numerical calculation or misalignment amount table 13a.

In the calculation of the misalignment amount performed by the control unit 110, the position detection scanning line echo ED existing for one scan is used retrospectively from any step in the scan.
FIG. 10 shows a case where one scan is traced back from the current step (scanning line A (i + 5)) for calculating the misalignment amount. One scan is the same as in FIG. That is, the scanning line D is transmitted from the scanning line A in one scan. In FIG. 10, the current step (scan line A (i + 5)) is traced back from the scan line D to the scan line A by 4 steps. Assume that a plurality of position detection scanning line echoes ED are acquired in one scan. Assume that at least two different position detection scanning line echoes ED are acquired.

  In step S12, it is assumed that N position detection scanning line echoes ED for one scan are obtained. As described above, N is 2 or more. The N elements from which N data are acquired (one element is transmitted by the position detection scanning line) are covered by the control unit 110 so that the misalignment amount can be accurately calculated. It is selected so as to cover the entire range of angles. Further, the N number is a sufficient number of data to keep the accuracy of the misalignment amount.

<Step S13>
The control unit 110 determines whether to calculate the misalignment amount from calculation or to determine the misalignment amount using the misalignment amount table 13a. The control unit 110 determines as follows. The control unit 110 makes a determination from the condition code specified before the start of flaw detection. The condition code is a code that specifies whether the misalignment amount is obtained by calculation or by using the misalignment amount table 13a. A condition code is preset in the control unit 110.
Alternatively, as another determination method, a speed measuring device that measures the passing speed (conveying speed) of the round bar 31 (test body) is arranged in front of the flaw detection apparatus. The control unit 110 receives the speed of the round bar 31 measured by the speed measuring device, compares the speed with a preset threshold value, and calculates the misalignment amount from the calculation when the speed is equal to or less than the threshold value. When the speed exceeds the threshold, the misalignment amount table 13a is used to determine the misalignment amount.

<If YES in Step S13 → Step S14a>
The control unit 110 obtains the misalignment amount from the calculation. As shown in FIG. 11, the positional relationship between the N position detection scanning line echoes ED and the round bar 31 is centered on the position of the element that has transmitted and received the position detection scanning line, and the radius r is the position detection scanning line echo ED. The round bar 31 (circle of the cross section of the round bar 31) is positioned so as to circumscribe the circle. Using this positional relationship, the control unit 110 can perform numerical calculations and obtain the misalignment amounts (Δx, Δy) from the numerical calculations. The radius r1 or the like is a distance between two points between the transmission position of each element and the reflection position of the surface of the round bar 31. In this example, the misalignment amount (Δx, Δy) is the actual round bar when the center as the known normal position of the round bar 31 with respect to the array probe 19a is the coordinate (0, 0). 31 center coordinates. That is, the coordinates of the center of the cross section in the normal position of the round bar 31 at the normal position of the round bar 31 with respect to the array probe 19a is (0, 0). With respect to the coordinate (0, 0), the center of the round bar 31 detected by the array probe 19a is the coordinate (Δx, Δy), and this coordinate indicates the misalignment amount. In this case, the coordinates (Δx, Δy) are the test body position, which is the amount of positional deviation from the normal position of the test body.

<If NO in Step S13 → Step S14b>
The control unit 110 obtains the misalignment amount (Δx, Δy) using the misalignment amount table 13a which is an example of the misalignment amount table.
FIG. 12 shows the misalignment amount table 13a. The misalignment amount table 13 a is stored in the auxiliary storage device 13. ED1 to EDN in the uppermost row indicate distances between two points between the position of the element and the reflection position of the round bar 31 with respect to the position detection scanning line 1 to the position detection scanning line N. Note that ED1 to EDN may be the time from the transmission time to the reception time of each of the position detection scanning lines 1 to N instead of the distance between the two points. Below the second row, the correspondence between each range of ED1 to EDN and the misalignment amount (Δx, Δy) is shown. a, b, etc. indicate numerical values. For example, in the second line, when each of ED1 to EDN belongs to the ranges of a to b, c to d, and ef, the misalignment amount (Δx, Δy) becomes (Δx1, Δy2). The third line indicates that the misalignment amount (Δx, Δy) is (Δx2, Δy) when each of ED1 to EDN belongs to the ranges of g to h, i to j, and k to l. y2). The control unit 110 obtains the values of ED1 to EDN from the position detection scanning line ED acquired in step S12, and refers to the misalignment amount table 13a of FIG. ). The control unit 110 issues an alarm using the alarm unit 111 when the misalignment amount (Δx, Δy) obtained in step S14a or step S14b exceeds a threshold value.

<Step S15>
The control unit 110 determines whether the correction amount of the transmission / reception condition of the flaw detection scanning line is obtained by calculation using the obtained misalignment amount, or is obtained using the transmission / reception condition table 13b using the obtained misalignment amount. . The determination method is the same as in step S13. The condition code and the threshold value may be the same as those in Step S13, or a condition code and a threshold value unique to Step S15 may be used. The controller 110 corrects the vertical scanning line and the oblique scanning line according to the misalignment amount (Δx, Δy) by using the misalignment amount (Δx, Δy). Control unit 110 obtains a correction amount (delay time described later) by calculation using misalignment amounts (Δx, Δy), or transmission / reception condition table 13b from which a correction amount is obtained from misalignment amounts (Δx, Δy). Is used to obtain the correction amount (delay time) regardless of the calculation.

  When there is a misalignment amount (Δx, Δy), various flaw detection scanning lines do not have the propagation path as set, which causes a decrease in echo level and a deterioration in S / N of the flaw echo. Therefore, the control unit 110 reflects the misalignment amount (Δx, Δy) in the flaw detection scanning line setting (scanning line transmission / reception conditions). By reflecting the misalignment amount (Δx, Δy) in the flaw detection scanning line setting, even when the misalignment amount (Δx, Δy) is present, the ultrasonic beam is set to have the set refraction angle. Can be controlled.

<If YES at step S15 → Step S16a>
The control unit 110 obtains a delay time for beam control, which is a correction amount for transmission / reception conditions, by numerical calculation.
FIG. 13 is a diagram schematically illustrating a case where the control unit 110 obtains a transmission / reception condition by calculation. Step 16a will be described with reference to FIG. When the round bar 31 has a misalignment amount, a distance difference ΔR is generated in the distance from each scanning line to the target position. FIG. 13 shows five scanning lines, and the distance difference ΔR _i and the distance difference ΔR _i−1 are shown for the two scanning lines. In FIG. 13, the solid circle is the normal position of the round bar 31 (no misalignment). A broken-line circle indicates the round bar 31 at the misalignment position. The center of the regular round bar 31 is also the center of curvature of the surface 19a-1 of the array probe 19a. The alternate long and short dash line 19a-2 corresponds to the surface 19a-1 when viewed from the round bar 31 at the misalignment position. Therefore, the distance between the center 31a of the round bar 31 at the misalignment position and the one-dot chain line 19a-2 is equal to R. The distance between the center 31a and the arrow tip of each scanning line is R. A distance difference ΔR between the scanning lines is obtained by subtracting R from the distance between the center 31a and the surface 19a-1. The distance difference between the scanning lines is assumed to be ΔR _i , ΔR _i−1 , ΔR _i−2 .
The control unit 110 obtains the transmission delay time in the transmission / reception conditions, for example, using the following formula.
Transmission delay time = (ΔR _k −ΔR _k−1 ) / sound speed.
Here, (ΔR _k −ΔR _k−1 ) means a difference in distance difference ΔR between adjacent scanning lines. For example, (ΔR _i −ΔR _i−1 ) or (ΔR _i-1 -ΔR _i-2 ). The reception delay time can use the same value as the transmission delay time.

<If NO in Step S15 → Step S16b>
The delay time for beam control is generally obtained by numerical calculation, but in order to increase the processing speed, the delay time for beam control (scan line control) with respect to the misalignment amount (Δx, Δy) in advance. Is used for the transmission / reception condition table 13b. The transmission / reception condition table 13 b is stored in the auxiliary storage device 13.
FIG. 14 is a diagram showing the transmission / reception condition table 13b. The transmission / reception condition table 13b indicates correspondence between misalignment amounts (Δx, Δy) and transmission / reception conditions. A, B, etc. indicate transmission / reception conditions. For example, when the misalignment amount (Δx, Δy) is (0.5 mm, 0 mm), the transmission / reception condition is B. In the transmission / reception condition B, transmission delay time and reception delay time are defined for each element forming each flaw detection scanning line. In the transmission / reception condition B in the transmission / reception condition table 13b, for example, the transmission delay time and the reception delay time of the elements 1 to 0 for the elements 1 to 20 that form the flaw detection scanning line 1 described in FIG. * 20 and ** 1 to ** 20 are defined. * 1, ** 1, etc. indicate numerical values. The same applies to the elements 21 to 40 and the elements 41 to 60 forming the flaw detection scanning line 2 and the flaw detection scanning line 3 described with reference to FIG. The control unit 110 determines the transmission / reception conditions using the transmission / reception condition table 13b from the misalignment amount (Δx, Δy) acquired in step S16a or step S16b. The control unit 110 can select an appropriate transmission / reception condition (delay time) for the misalignment amount (Δx, Δy) at high speed by using the transmission / reception condition table 13b.

<Step S17>
The control unit 110 reflects the beam control condition (delay time) obtained in step S16a or step S16b in the beam control condition of the next step after that step as described with reference to FIG.

With reference to FIG. 15 and FIG. 16, the calculation method by the control part 110 in step S14a of FIG. 6 is demonstrated.
FIG. 15 shows the case of Calculation Example 1. In FIG. 15, the solid circle indicates the position of the regular round bar 31, and the alternate long and short dash line indicates the round bar 31 when misaligned. A circle including a broken line indicates a circle whose radius is the curvature radius R of the array probe, and the center of this circle coincides with the center of the regular round bar 31.
FIG. 16 shows the case of Calculation Example 2. 15 and 16 show examples of calculation methods for obtaining the misalignment amount (Δx, Δy).

<Calculation Example 1>
First, FIG. 15 will be described. The virtual center (Δx, Δy) of the round bar 31 at the time of eccentricity is obtained as follows. The virtual center point (Δx, Δy) becomes the misalignment amount (Δx, Δy). Ultrasound is transmitted and received at any two or three predetermined points (points with clear coordinates). These points are the transmission positions of the respective elements that transmit and receive the position detection scanning line. The control unit 110 acquires the distance L1 and the distance L2 (in the case of three points, the distance L3) from the transmission / reception result. The distance L1 or the like is a distance between two points between the element and the surface of the round bar 31. The control unit 110 identifies the quadrant of the virtual center point (Δx, Δy). The control unit 110 calculates the center coordinates (eccentricity) of the round bar 31 from simultaneous equations of the following formulas 1 and 2 (further formula 3 in the case of 3 points). The case where the misalignment amount table 13a and the transmission / reception condition table 13b are used is as follows. The control unit 110 searches the misalignment amount table 13a and the transmission / reception condition table 13b. The control unit 110 automatically sets preset data (without misalignment) in the transmission / reception condition table 13b in the transmission / reception unit 14, and the transmission / reception unit 14 updates the transmission / reception condition (irradiation direction) at the next transmission / reception timing (next step). Send and receive.

^{(R + L2) 2 = (} X + △ x) 2 + (Y + △ y) 2 ( Equation 1)
^{(R + L1) 2 = (} X- △ x) 2 + (Y + △ y) 2 ( Equation 2)
^{(R + L3) 2 = (} △ x) 2 + (Y + Y '+ △ y) 2 ( Equation 3)
Where Y ′ = R−Y,
The origin (0, 0) of the coordinate axis is the center of the round bar 31 at the normal position of the round bar 31 with respect to the array probe.
L1, L2, L3: distance between each element and the surface of the round bar 31,
r: radius of the round bar 31,
X and Y: the position of each element,
R: radius of curvature of the surface of the array probe.
(1) When the radius r of the round bar 31 is known The control unit 110 obtains two unknowns Δx and Δy based on the simultaneous expression of Expression 1 and Expression 2.
(2) When the radius r of the round bar 31 is unknown, the control unit 110 obtains three unknowns Δx, Δy, and r by simultaneous equations 1 to 3.

<Calculation Example 2>
Calculation Example 2 will be described with reference to FIG. In FIG. 16, the solid circle indicates the position of the regular round bar 31, and the alternate long and short dash line circle indicates the round bar 31 at the time of misalignment. A circle including a broken line indicates a circle whose radius is the curvature radius R of the array probe, and the center of this circle coincides with the center of the regular round bar 31. With respect to the position detection scanning line m of the third element m from the top in FIG. 16, the horizontal distance and vertical distance to the element m as viewed from the center of the round bar 31 at the time of misalignment are
<Δx + Rcos θm, Δy + Rsin θm>.
When the position detection scanning line m intersects the surface of the round bar 31 at the time of misalignment, the horizontal distance and the vertical distance from the point intersecting the center of the round bar 31 at the time of misalignment are
<R × cosφm, r × sinφm>
It is. here,
If θm ≒ φm,
<R × cos θm, r × sin θm> can be written.
Therefore, applying the three square theorem to the right triangle mbc,
(Lm) ² = (Δx + (R−r) cos θm) ² + (Δy + (R−r) sin θm) ² (Formula 4)
Is established. The control unit 110 can determine the unknowns (Δx, Δy, r) from the three equations by establishing Equation 4 for the three elements with different Lm and θm.
Lm: a detection distance between the element a and the surface of the round bar 31 at the time of misalignment,
φm: angle formed by the element a and the center of the round bar 31 at the time of misalignment,
θm: angle formed by the element a and the center of the round bar 31 at the normal position,
r: radius of the round bar 31

<Example of other specimen 30>
As an example other than the round bar 31, a case where a square member 32 having a square cross section is described as the test body 30 will be described.
17 and 18 are diagrams for explaining the case of the square member 32. FIG. In the case of the square member 32 shown in FIG. 17, the position detection scanning line is not a spherical wave, but a narrow directivity similar to the flaw detection scanning line is used.
As shown in FIG. 17, in the array probe 33, the surface on which a plurality of elements are arranged is not a curved surface but a flat surface. FIG. 18 shows a detection result by the array probe 33 and corresponds to (a) or (b) of FIG. FIG. 18 shows the distance in the vertical direction (Y direction) between the arrangement surface 33a where a plurality of elements are arranged in the array probe 33 and the square member surface 32a with respect to the arrangement surface 33a. The control unit 110 can determine the transmission / reception conditions of the flaw detection scanning line using the detection result of FIG.

*** Effects of Embodiment 1 ***
(1) The ultrasonic flaw detector 10 corrects transmission / reception conditions for each array probe. Therefore, the ultrasonic flaw detector 10 is not affected by the relative positional deviation of the array probe due to the arrangement of the plurality of array probes and the manufacturing error of the curvature radius R of the curved surface on which the elements are arranged in the array probe. Can be flawed.
(2) The ultrasonic flaw detector 10 corrects the transmission / reception conditions for each array probe. Therefore, even when the test body 30 is bent, the correction of the transmission / reception conditions is not affected by the bend. In other words, transmission / reception conditions that reflect the influence of bending can be corrected.
(3) The ultrasonic flaw detector 10 can determine the diameter of the round bar 31 by numerical calculation. Therefore, in this case, the manufacturing error of the round bar 31 is not affected by the misalignment calculation.
(4) When a single array probe is used and the round bar 31 is conveyed while being rotated and a single array probe is used for flaw detection, a plurality of array probes are circumferentially arranged around the round bar 31. It can perform flaw detection similar to flaw detection where a child is placed. Even in this case, misalignment correction can be performed.

  DESCRIPTION OF SYMBOLS 10 Ultrasonic flaw detector, 11 Processor, 110 Control part, 111 Alarm part, 12 Main memory, 13 Auxiliary memory, 13a Misalignment amount table, 13b Transmission / reception condition table, 14 Transmission / reception part, 15 Bus, 18 Signal line, 19a , 19b, 19c, 19d Array probe, 19a-1 surface, 21b ultrasonic beam, 26 probe holder, 30 specimen, 31 round bar, 31a center, 32 square member, 32a square member surface, 33 array probe , 33a Arrangement surface, 40 frame, 41 Transport direction.

Claims (8)

An array probe that transmits and receives ultrasonic waves toward a test body having a longitudinal shape and conveyed in the longitudinal direction;
A plurality of position detection scanning lines for detecting the position of the test body are transmitted to the array probe as the ultrasonic wave, and each position detection scanning line reflected on the surface of the test body is transmitted to the array probe. By calculating the distance between two points between the known transmission position of each of the position detection scanning lines and the reflection position of the surface of the specimen,
Based on a plurality of the transmission positions and the distance between the two points corresponding to each of the transmission positions, determine a specimen position indicating the position of the specimen relative to the array probe;
In accordance with the determined position of the test body, an ultrasonic flaw detection device comprising a control unit for determining a transmission / reception condition indicating a transmission condition and a reception condition of a flaw detection scanning line that is the ultrasonic wave for flaw detection transmitted / received by the array probe. apparatus. The array probe has a plurality of elements,
The controller is
The ultrasonic flaw detector according to claim 1, wherein each of the position detection scanning lines is transmitted and received by one element. The controller is
Determining the amount of displacement of the specimen from a known normal position of the specimen relative to the array probe as the specimen position;
The ultrasonic flaw detection apparatus according to claim 1, wherein the transmission / reception condition of the flaw detection scanning line is determined according to the determined amount of displacement. The controller is
The ultrasonic flaw detection apparatus according to claim 3, wherein the displacement amount is determined and determined from a calculation using a plurality of distances between the two points. The controller is
The ultrasonic flaw detector according to claim 3 or 4, wherein the transmission / reception condition is determined by calculation based on a calculation using the positional deviation amount. The controller is
The ultrasonic flaw detection apparatus according to claim 3, wherein the positional deviation amount is determined using a positional deviation amount table capable of determining the positional deviation amount from a plurality of distances between the two points. The controller is
The ultrasonic flaw detection apparatus according to claim 3 or 6, wherein the transmission / reception condition is determined using a transmission / reception condition table capable of determining the transmission / reception condition from the positional deviation amount.   The ultrasonic flaw detector according to any one of claims 3 to 7, further comprising an alarm unit that outputs an alarm when the positional deviation amount determined by the control unit exceeds a threshold value.

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