JP2010190794A - Thinning detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thinning detection method for determining the presence or absence of a thinned part which has occurred in a section to be inspected even when the section to be inspected is not exposed due to a deposit such as a support member and a reinforcing member. <P>SOLUTION: The thinning detection method includes a first process for arranging an ultrasonic transmission-side probe 11 and an ultrasonic reception-side probe 12 at a prescribed interval in the surface of a specimen 36 having a sound thickness of a section to be inspected 14 to receive ultrasonic waves entering the specimen 36 from the transmission-side probe 11, skipping a plurality of times in such a way as to be reflected at its back and surface, and reaching the reception-side probe 12 and to obtain echoes of a sound part; a second process for arranging the transmission-side probe 11 and the reception-side probe 12 at a prescribed interval on both sides of the section to be inspected 14 to receive ultrasonic waves entering the section to be inspected 14 from the transmission-side probe 11, skipping a plurality of times, and reaching the reception-side probe 14 and to obtain echoes of the section to be inspected; and a third process for comparing the locations of occurrence of the echoes of the sound part obtained in the first process with the echoes of the section to be inspected obtained in the second process and determining the presence or absence of a thinned part 17 which has occurred in the section to be inspected 14 on the basis of their difference. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a thinning detection method for inspecting the presence or absence of a thinning portion generated due to corrosion or the like in plate materials and pipe materials of various plants.

Inspection of thinning caused by corrosion or the like in plate materials and pipe materials of various plants is performed using, for example, an ultrasonic vertical probe (ultrasonic vertical flaw detection test). However, in the method using the ultrasonic vertical probe, the ultrasonic vertical probe is operated by bringing the ultrasonic vertical probe into contact with the surface of the examination site, and therefore, the ultrasonic vertical probe is operated above the examination site of the subject. Space is required. For this reason, for example, when the pipe is supported by an H-shaped steel called a rack, the contact part between the pipe and the rack, the part where the backing plate (reinforcement plate) or support material is welded with the plate, the surface of the inspection site The ultrasonic vertical probe could not be brought into contact with, and the inspection could not be performed.

Therefore, as shown in FIG. 12 (A), when inspecting the presence / absence of the thinned portion 103 occurring in the inspection region 102 with the portion immediately below the plate member 100 welded to the plate 101 as the inspection region 102, The ultrasonic wave sending and receiving elements 104 and 105 are arranged at a certain distance WA so as to straddle the plate 101 on the surface of the plate material 100, and the sending and receiving elements 104 and 105 are arranged between the sending and receiving elements 104 and 105. As shown in FIG. 12 (B), the surface wave R is moved from the transmitter 104 to the inspection region while the distance WA is kept constant and is moved in the direction orthogonal to the line connecting the transmitter and receiver 104, 105. The propagation time until it passes through 102 and reaches the receiver 105 is measured, and the reference propagation time t _{WA of the} surface wave determined in accordance with the distance WA between the transmission and the receivers 104 and 105 obtained in advance (that is, , Thinning part 103 Surface wave testing area no health condition is compared with the propagation time) as it passes. Here, when the thinned portion 103 is generated in the inspection region 102, the surface wave travels along the surface of the thinned portion 103, and therefore the surface wave travel becomes long, and the propagation time _tWB of the surface wave is Since it is longer than the reference propagation time, a surface wave transmission method has been proposed in which the presence or absence of the thinned portion 103 occurring in the examination region 102 is determined from the presence or absence of the surface wave propagation time difference Δt (for example, , See Patent Document 1).

Further, as shown in FIG. 13A, when inspecting the thinned portion 109 generated on the back side of the inspection site 108, the portion where the plate 107 is welded to the plate material 106 is used as the inspection site 108. The ultrasonic wave sending and receiving elements 110 and 111 are arranged on the surface of the plate material 106 so as to straddle the contact plate 107, and the distance between the sending and receiving elements 110 and 111 is kept constant between the sending and receiving elements 110 and 111. As shown in FIG. 13B, the ultrasonic wave S is transmitted from the transmitter 110 to the examination site 108 at a constant incident angle while moving in a direction orthogonal to the line segment connecting the transmitter and receiver 110 and 111. The transmitted echo height H ′ obtained by reaching the receiver 111 after being entered and reflected several times on the back and front of the examination site 108 is obtained. Here, when the thinned portion 109 occurs in the inspection site 108, the ultrasonic wave incident on the thinned portion 109 is reflected on the bottom surface of the thinned portion 109 and the process changes and does not reach the receiver 111. The intensity of the ultrasonic wave received by the receiver 111 is lowered. For this reason, the transmission echo height H ′ is compared with the reference transmission echo height H determined in accordance with the transmission, the distance between the receivers 110 and 111 and the thickness of the examination site 108, which are obtained in advance. There has also been proposed an oblique transmission method that determines that the thinned portion 109 is present at the examination site 108 when an echo height difference ΔH occurs between the echo height H ′ and the reference transmission echo height H.

JP 2002-5905 A

However, in the surface wave transmission method, when the surface of the examination site (subject) is greatly rough, the surface wave is greatly attenuated and measurement becomes difficult, and the measurement accuracy is greatly affected by the surface properties of the examination site. There is. Further, since the difference in propagation time (propagation distance) of the surface wave is obtained, there is a problem that only the thinned portion generated on the surface of the examination site can be inspected.
On the other hand, in the oblique transmission method, the ultrasonic wave reaching the receiver after being reflected multiple times on the back and front of the examination site is received and the transmission echo height is obtained. Therefore, the measurement accuracy depends on the surface properties of the front and back sides of the examination site. There is a problem of being greatly influenced.

The present invention has been made in view of such circumstances, and a thinning detection method capable of determining the presence or absence of a thinned portion generated in an examination site even when the examination site is not exposed due to an adherent such as a support member or a reinforcing member. The purpose is to provide.

The thinning detection method according to the present invention that meets the above-described object is characterized in that a transverse wave oblique angle probe that forms a pair that becomes a transmitting probe and a receiving probe of an ultrasonic wave with a predetermined interval is used as an inspection site. Placed on the surface of a specimen having a healthy thickness of the ultrasonic wave that enters the specimen from the transmitter probe and performs multiple skips that are reflected from the back and front, and reaches the receiver probe. A first step of receiving and obtaining a healthy part echo;
The transmitting probe and the receiving probe are arranged on both sides of the inspection region with the interval, and a plurality of light beams that enter the inspection region from the transmitting probe and reflect on the back and front sides. A second step of skipping times and receiving an ultrasonic wave reaching the receiving probe to obtain an inspection portion echo;
Compare the occurrence position of the healthy part echo obtained in the first step and the inspection part echo obtained in the second step, and determine the presence or absence of a thinned part occurring in the examination site from the difference And a third step.

In the thinning detection method according to the present invention, in the determination of the presence or absence of the thinning portion in the third step, in addition to the difference in the generation position of the healthy portion echo and the inspection portion echo, the height of the inspection portion echo is also determined. It is preferable to take this into consideration.

In the thinning detection method according to the present invention, it is preferable that the thinning portion is detected at a central portion of the transmitting probe and the receiving probe.
Here, the interval may be set to a distance at which the ultrasonic wave reaches the receiving probe through the odd number of skips, and the thinned portion generated on the back surface of the examination site may be detected. .
Moreover, the said thinning part currently generate | occur | produced on the surface of the said test | inspection site | part may be detected by setting the said space | interval to the distance which an ultrasonic wave reaches the said reception side probe through the said skip of the even number of times.

In the thinning detection method according to the present invention, the depth of the thinning portion can be obtained from a difference between occurrence positions of the healthy portion echo and the inspection portion echo.

In the thinning detection method according to the present invention, it is preferable that the transmission side probe and the reception side probe have the same incident angle, and those of 45 degrees or more and 75 degrees or less are used.

In the thinning detection method according to the present invention, the transmitting probe and the receiving probe are kept constant on the surface of the inspection site, and the transmitting probe and the receiving probe are kept constant. The range of the thinned portion can be measured by moving the probe in a direction orthogonal to the line segment connecting the probes.

In the thinning detection method according to the present invention, the transverse wave oblique angle probe which is a pair that becomes a transmitting side probe and a receiving side probe of the ultrasonic wave having a predetermined interval is disposed, so that the support member Inspection can be carried out even when deposits such as reinforcing members are present on the surface of the inspection site and the inspection site is not exposed. In addition, since the ultrasonic wave reaching the receiving probe is received by performing a plurality of skips that enter the inspection site from the transmitting probe and reflect on the back and front, the inspection site can be set in a wide range. Furthermore, since the presence or absence of the thinned portion occurring in the examination part is determined from the difference by comparing the occurrence position of the healthy part echo and the examination part echo, it is difficult to be affected by the surface properties of the front and back surfaces of the examination part, It is possible to accurately determine the presence or absence of a thinned portion occurring at the examination site.

In the thinning detection method according to the present invention, in the case where the determination of the presence or absence of the thinning portion in the third step is performed in consideration of the height of the inspection portion echo in addition to the difference in the position where the sound portion echo and the inspection portion echo are generated. Therefore, it is possible to reliably detect the thinned portion generated between the transmission side probe and the reception side probe.

In the thinning detection method according to the present invention, when the thinning portion is detected at the center of the transmitting side probe and the receiving side probe, the presence or absence of the thinning portion is determined as the occurrence position of the healthy portion echo and the inspection portion echo. It can be judged from the difference.
Here, when an interval is set to the distance that the ultrasonic wave reaches the receiving probe through an odd number of skips and a thinned portion occurring on the back surface (bottom surface) of the examination site is detected, the sound part echo A part of the process of the ultrasonic wave forming can be replaced with a process of reflecting the ultrasonic wave between the back surface of the thinned portion and the surface of the inspection site. In addition, when an interval is set to the distance at which the ultrasonic waves reach the receiving probe through even-numbered skips, and a thinned portion generated on the surface of the examination site is detected, an ultrasonic wave that forms a sound portion echo is formed. A part of the sound wave process can be replaced with the process of reflection of ultrasonic waves between the bottom surface of the thinned portion and the back surface of the inspection site, and the inspection part echo can be generated in the immediate vicinity of the sound part echo.

In the thinning detection method according to the present invention, when the depth of the thinned portion is obtained from the difference between the occurrence positions of the sound portion echo and the inspection portion echo, the depth of the thinned portion can be accurately and easily obtained.

In the thinning detection method according to the present invention, when the transmission side probe and the reception side probe have the same incident angle and are 45 degrees or more and 75 degrees or less, respectively, the transmission and reception side probes are used. The sound part echo and the inspection part echo can be easily obtained according to the interval between the tentacles and the thickness of the inspection part.

In the thinning detection method according to the present invention, the transmitting probe and the receiving probe are connected to each other at a constant interval on the surface of the inspection site, and the transmitting probe and the receiving probe are connected to each other. When the range of the thinned portion is measured by moving in the direction orthogonal to the line segment, the distribution of the thinned portion in the examination site can be easily obtained.

It is explanatory drawing of the thinning detection apparatus used with the thinning detection method which concerns on the 1st Embodiment of this invention. (A) is explanatory drawing which shows generation | occurrence | production of a sound part echo, (B) is a schematic diagram which shows the generation | occurrence | production position of sound part echo. (A), (B) is explanatory drawing which shows the movement method of the transmission side probe in a 2nd process, and a receiving side probe. (A) is explanatory drawing of the path | route of an ultrasonic wave when a thinning part exists, (B) is a model which shows the relationship of the generation | occurrence | production position of the test | inspection part echo and healthy part echo which are obtained when a thinning part exists. FIG. In (A), the interval between the transmitting probe and the receiving probe is adjusted so that the number of skips is an even number, with the thinned portion being the central portion of the transmitting probe and the receiving probe. FIG. 6B is a schematic diagram showing the relationship between the generation positions of the examination part echo and the healthy part echo. It is explanatory drawing when the path length of an ultrasonic wave changes with a thinning part. (A), (B), (C) are respectively a front view, a partially omitted plan view of a measurement jig of a thinning detection device used in the thinning detection method according to the second embodiment of the present invention, FIG. (A), (B) is explanatory drawing of the thinning detection of Example 1. FIG. (A), (B) is explanatory drawing of the transmission echo of Example 1, (C) is a two-dimensional distribution map of a thinning part. (A), (B) is explanatory drawing of the thinning detection of Example 2. FIG. (A), (B) is explanatory drawing of the transmission echo of Example 2, (C) is a two-dimensional distribution map of a thinning part. (A) is explanatory drawing of the thinning detection method based on a prior art example, (B) is explanatory drawing which shows the change of the propagation time of a surface wave. (A) is explanatory drawing of the thinning detection method which concerns on a prior art example, (B) is explanatory drawing which shows the change of the transmitted echo height.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.

As shown in FIG. 1, a thinning detection apparatus 10 used in the thinning detection method according to the first embodiment of the present invention is an ultrasonic transmission side probe comprising a pair of transverse wave oblique angle probes. The probe 11 and the receiving probe 12, and the transmitting probe 11 and the receiving probe 12 are arranged with a predetermined interval Ys on both sides of the inspection site 14 of the plate 13 which is an example of the subject. At the same time, the transmission side probe 11 and the reception side probe 12 are kept on the surface of the inspection site 14 while keeping the distance Ys between the transmission side probe 11 and the reception side probe 12 constant. A measurement jig 15 that moves in a direction orthogonal to a line segment connecting the transmission side probe 11 and the reception side probe 12 and a drive signal that causes a transverse wave to enter the inspection site 14 from the transmission side probe 11 are transmitted. Input to the side probe 11 and skip multiple times to reflect on the back and front of the test site 14 and receive side probe And a ultrasonic flaw detector 16 to take out the echo signal output from the receiving side probe 12 when the ultrasound is received reaching the 12. Since a conventional ultrasonic flaw detector can be used as the ultrasonic flaw detector 16, a detailed description is omitted.

Further, as shown in FIG. 2 (A), the thinning detection apparatus 10 has a predetermined interval Ys on the surface of a plate-like test body 36 that is the same material as the plate material 13 and has the same thickness as the healthy thickness of the inspection site 14. The transmission side probe 11 and the reception side probe 12 are arranged to pass through the test body 36 from the transmission side probe 11 and reach the reception side probe 12 via the ultrasonic flaw detector 16. A sound portion echo storage function for obtaining and storing sound portion echoes from the echo signals extracted in this manner, the transmitting side probe 11 and the receiving side probe 12 having an interval Ys disposed at the inspection site 14 of the plate 13. An inspection part echo detection function for obtaining an inspection part echo from an echo signal that has passed through the inspection part 14 from the transmission side probe 11 and reached the reception side probe 12 and taken out via the ultrasonic flaw detector 16; Comparison of the location of the echo of the head and the test part査部 position has analysis means 18 having a first wall thinning determination function determines the presence or absence of thinning portion occurring on 14.

Here, the measuring jig 15 is provided on each side of the bar member 19 that can be expanded and contracted and can be fixed to an arbitrary length, and on both sides of the bar member 19, and the transmission side probe 11 and the reception side probe 12 are respectively connected. Probe holders 20a and 20b that hold and urge the contact surfaces 24a and 24b of the transmitting probe 11 and the receiving probe 12 toward the surface of the inspection site 14 of the plate 13 with a constant pressing force. And a pair of wheels 21 which are attached to positions on both sides of the rod member 19 so as not to interfere with the probe holders 20a and 20b, and whose axle direction is oriented parallel to the axial direction of the rod member 19, and one wheel. And an encoder 22 that measures the moving distance of the bar member 19 from the number of rotations 21 and outputs a measurement signal to the analysis means 18.

With such a configuration, the contact surfaces 24a and 24b of the transmitting probe 11 and the receiving probe 12 are contacted with the contact medium (for example, water, glycerin, grease, etc.) on the surface of the inspection site 14 of the plate 13. The transmission side probe 11 and the reception side probe 12 on the surface of the inspection site 14, and the transmission side probe 11 and reception. The distance Ys between the side probes 12 can be kept constant and can be moved in the direction orthogonal to the line segment connecting the transmission side probe 11 and the reception side probe 12.

The transmission side probe 11 and the reception side probe 12 are in contact with the ultrasonic vibration elements A and B to which signal input / output signal cables 23a and 23b are connected, respectively, and the ultrasonic vibration elements A and B. A waveguide member (not shown) for taking out transverse waves emitted from the ultrasonic vibration elements A and B; a contact surface 24a in which one surface is in contact with the waveguide member and the other surface is in contact with the surface of the inspection site 14 of the plate 13; 24b, contact portions (not shown), ultrasonic vibration elements A and B, waveguide members, and probe cases 25a and 25b that house the contact portions. Here, the frequency of the ultrasonic vibration elements A and B is 3 MHz or more, preferably 3.5 MHz or more, 7 MHz or less, preferably 5 MHz or less. Further, when the ultrasonic vibration elements A and B are circular, the diameter thereof is 4 mm or more, preferably 6 mm or more, 15 mm or less, preferably 13 mm from the point of the flaw detection cover range (two-dimensional size of the thinned portion 17). The following is recommended.

In the transmitting probe 11, when the transmitting probe 11 is brought into contact with the test site 14, the test site 14 is set at a certain incident angle, for example, the contact surface 24a via the contact surface 24a. The angle θ with the perpendicular is 45 ° or more, preferably 50 ° or more, 75 ° or less, and preferably 70 ° or less, and the ultrasonic vibration elements A and B in the probe case 25a are guided. The angle and position of the wave member are adjusted. In the receiving probe 12, when the receiving probe 12 is brought into contact with the inspection site 14, a constant incident angle, for example, on the contact surface 24 b, is incident on the contact surface 24 b through the surface of the inspection site 14. The ultrasonic vibration elements A and B in the probe case 25b so that the angle φ with respect to the standing perpendicular is 45 ° or more, preferably 50 ° or more, and 75 ° or less, preferably 70 ° or less. The angle and position of the waveguide member are adjusted.

Further, the analysis means 18 includes a second thinning determination function for determining the presence or absence of the thinning portion 17 based on the difference in the generation position of the healthy portion echo and the inspection portion echo and the height of the inspection portion echo, and the healthy portion echo. Based on the difference between the detection position of the inspection portion echo and the thickness of the thinning portion 17 for obtaining the depth of the thinning portion 17, the measurement signal of the movement distance of the bar member 19 output from the encoder 22, and the inspection portion echo. A thinning portion distribution measuring function for measuring the range of the meat portion 17 is provided. The analysis means 18 can be formed, for example, by mounting a program that expresses each of the above functions on a microcomputer.

The thinning detection method according to the first embodiment of the present invention uses a measurement jig 15 shown in FIG. 1 and has a predetermined interval Ys as shown in FIG. The sound wave transmitting side probe 11 and the receiving side probe 12 are arranged on the surface of the test body 36 having a sound thickness of the inspection site 14 of the plate member 13 and enter the test body 36 from the transmission side probe 11. The first step of obtaining the sound part echo by receiving the ultrasonic wave reaching the receiving side probe 12 by skipping a plurality of times reflected on the back and front, and using the measuring jig 15 as shown in FIG. The transmission side probe 11 and the reception side probe 12 are arranged at the inspection site 14 of the plate 13 with a predetermined interval Ys, and enter the inspection site 14 from the transmission side probe 11 to enter the back side and the front side. The second step is to obtain the inspection part echo by receiving the ultrasonic wave that reaches the receiving probe 12 by skipping multiple times reflected by Degree and, and a third step of determining whether the thinning portion occurring on the test site 14 from the difference by comparing the occurrence position of the inspection unit echo a healthy section echoes. Details will be described below.

(First step)
As shown in FIG. 2 (A), the transmitting probe 11 has a constant incident angle θ (at an angle of 45 ° or more with a perpendicular standing on the contact surface 24a of the transmitting probe 11) on the specimen 36. The ultrasonic wave enters at an angle range of preferably 50 ° or more and 75 ° or less, and preferably 70 ° or less. On the other hand, the receiving probe 12 has a certain incident angle φ (receiving probe) on the contact surface 24b of the receiving probe 12 in the ultrasonic wave reflected from the back surface of the test body 36 and directed to the surface. The incident ultrasonic wave is received at an angle of 45 ° or more, preferably 50 ° or more, and 75 ° or less, preferably 70 ° or less) with respect to a perpendicular standing on the contact surface 24b of the child 12. The incident angles θ and φ are the same.

Here, as shown in FIG. 2A, the process of entering the surface of the specimen 36 (thickness t) from the transmitting probe 11 at an angle θ, reflecting on the back surface, and returning to the surface is referred to as one skip. When the ultrasonic wave that has entered the specimen 36 from the transmission side probe 11 skips S times and enters the reception side probe 12 at an incident angle φ (= θ), the transmission side probe 11 The S skip distance Ws that is fired and reaches the receiving probe 12 and the interval Ys between the transmitting probes 11 and 12 satisfy the following relationship.
Ws = S · 2t / cos θ
Ys = S · 2t · tanθ

Further, as shown in FIG. 2A, the ultrasonic wave is incident on the test body 36 from the transmitting probe 11 in the front and rear angle ranges around the incident angle θ, and the incident angle is Since ultrasonic waves are incident on the transmitting probe 12 in the front and rear angle range with φ (= θ) as the center, ultrasonic waves having a path other than the path Ws are also received by the receiving probe 12. Here, when the transmitter probe 11 enters the surface of the test body 36 at an angle θ _sn and skips Sn times reflected from the back surface and the surface, the light enters the receiver probe 12 at an incident angle θ _sn. The following relationship is obtained.
Wns = Sn · 2t / cos θ _sn
θ _sn = tan ⁻¹ (Ys / 2t · Sn)

Therefore, when the number of skips S is set, that is, the interval Ys is determined and the transmitting probe 11 and the receiving probe 12 are arranged on the surface of the test body 36, the sound part echo composed of a plurality of transmitted echoes is generated. can get. The healthy part echoes Ws and Wns obtained from the echo signal output from the receiving probe 12 are collectively shown in FIG. In FIG. 2 (B), a healthy part echo generated on the short beam path side with respect to Ws having the maximum echo height is generated on the long beam path side with respect to W _−1s , W _−2s , and Ws. The _partial echoes are W _{+ 1s} , W _{+ 2s} , and W _{+ 3s} in order.

Here, the thickness t of the test body 36 (plate material 13) is preferably 4 mm or more so that a plurality of transmitted echoes are obtained separately as the sound part echo. In addition, although the maximum value of the thickness t of the test body 36 (plate material 13) is decided by the strength of the transverse wave to be used, it becomes about 20 mm when using a commercially available ultrasonic flaw detector.
Further, when the number of skips S is set, that is, when the transmission side probe 11 and the reception side probe 12 are arranged with the interval Ys determined, the measurement range in which the presence or absence of the thinning portion 17 can be determined is On the line segment connecting the probes 11 and 12, the range is from the point Ys / 2S to the point Ys−Ys / 2S starting from the transmitting probe 11. Here, the maximum length of the measurement range that can be determined is determined by the strength of the ultrasonic wave to be used, but is about 400 mm when a commercially available ultrasonic flaw detector is used.

Here, when the width of the inspection site 14 for determining whether or not the thinned portion 17 is generated is set, the incident angle θ of the ultrasonic wave incident on the test body 36 from the transmitting probe 11 and the test body 36 are set. Since the incident angle φ (= θ) of the ultrasonic wave incident on the receiving probe 12 is determined, the number of skips S is determined as a condition for obtaining a healthy part echo, and the transmitting probe 11 and the receiving probe An interval Ys between the touch elements 12 is determined. In addition, when it is going to detect the thinning part 17 which has generate | occur | produced in the back surface of the test | inspection site | part 14, the space | interval Ys between the transmission side probes 11 and 12 is set so that the skip number S may be 3 times or more. Therefore, it is desirable to obtain the healthy part echo at that time. In addition, when trying to detect the thinned portion 17 generated on the surface of the examination site 14, the interval Ys between the transmitting side probes 11 and 12 is set so that the skip number S is 4 times or more. Therefore, it is desirable to obtain the healthy part echo at that time.

(Second step)
As shown in FIG. 1, the transmitting probe 11 and the receiving probe 12 are arranged on the surface of the inspection site 14 of the plate member 13, and the distance between the transmitting probe 11 and the receiving probe 12 ( The flaw detection (movement) is performed while keeping the distance between the probes Ys constant. At this time, the range from one end of the measurement range where the transmission side probe 11 is arranged to Ys / S in the inner (reception side probe 12 side) direction and the reception side probe 12 are arranged. With respect to the range from the other end of the measurement range to Ys / S in the outward (non-transmission side probe 11 side) direction, the transmission side probe 11 and the reception side probe 12 are each in the flaw detection (moving) cover range. Are scanned so that they overlap.

For example, as shown in FIG. 3 (A), the transmission side probe 11 and the reception side probe 12 respectively arranged on one side of the examination range of the examination region 14 are replaced with the transmission side probe 11 and the reception side probe. After simultaneously moving Ys / S in the direction from the transmitting probe 11 to the receiving probe 12 along the line connecting the probes 12, the transmitting probe 11 and the receiving probe A line segment connecting between the transmission-side probe 11 and the reception-side probe 12 after simultaneously moving a predetermined distance toward the other side of the inspection range along a direction orthogonal to the line segment connecting the two. Are simultaneously moved in the direction from the receiving probe 12 toward the transmitting probe 11 by Ys / S, and further orthogonal to the line segment connecting the transmitting probe 11 and the receiving probe 12. A unit run that moves simultaneously along the direction toward the other side of the inspection range by a preset distance The repeated until the transmission side probe 11 and the reception-side probe 12 reaches the other side of the inspection range of the inspection site 14.

Alternatively, as shown in FIG. 3B, the transmitting probe 11 and the receiving probe 12 respectively arranged on one side of the inspection range of the inspection region 14 are replaced with the transmitting probe 11 and the receiving probe. After simultaneously moving to the other side of the inspection range along the direction orthogonal to the line segment connecting the transducers 12, the transmission side along the line segment connecting the transmitter probe 11 and the receiver probe 12 The distance between the probe 11 and the receiving probe 12 is changed to a line segment connecting the transmitting probe 11 and the receiving probe 12 after moving by a preset distance, for example, Ys / 2S, in the direction from the probe 11 to the receiving probe 12 at the same time. A line that connects the transmission side probe 11 and the reception side probe 12 between the transmission side probe 11 and the reception side probe 12 is moved to one side of the inspection range at the same time along the orthogonal direction. At the same time in the direction from the transmitting probe 11 to the receiving probe 12 Distance was, for example, after moving only Ys / 2S, further moves to the other side of simultaneously testing a range along the direction perpendicular to the line segment connecting between the transmission side probe 11 and the reception-side probe 12.

As a result, a position that is Ys / 2S from the receiving probe 12 and a position that is Ys / 2S from the receiving probe 12 (a position that is Ys-Ys / 2S from the transmitting probe 11). ) Can be detected without overlooking the thinned portion 17 existing in the range up to. Then, the ultrasonic wave reaching the reception side probe 12 is received by performing a plurality of skips that enter the inspection site 14 from the transmission side probe 11 and reflected on the back and front, and through the ultrasonic flaw detector 16. The output transverse echo signal is input to the analysis means 18 at regular time intervals. In addition, a measurement signal of the movement distance of the transmission side probes 11 and 12 is input from the encoder 22 to the analysis unit 18.

(Third step)
In the analysis means 18, the inspection part echo is obtained by receiving the ultrasonic wave that reaches the reception side probe 12 by performing a plurality of skips that enter the inspection site 14 from the transmission side probe 11 and reflect on the back and front. Then, a comparison is made between the generation position of the examination part echo and the stored position of the healthy part echo. When the thinning portion 17 does not exist on the path of the ultrasonic wave transmitted from the transmission side probe 11 and passed through the inspection site 14 and received by the reception side probe 12, the reception side probe 12 receives the signal. The inspection part echo generation position obtained in this manner matches the sound part echo generation position. On the other hand, as shown in FIG. 4A, on the back surface of the inspection site 14 on the path of ultrasonic waves transmitted from the transmission side probe 11, passing through the inspection site 14 and received by the reception side probe 12. When the thinned portion 17 is present, ultrasonic waves are reflected between the bottom surface of the thinned portion 17 and the surface of the inspection site 14, and an inspection portion echo is generated at a position different from the healthy portion echo. FIG. 4B shows the inspection part echo in contrast to the healthy part echo. And when the test | inspection part echo generate | occur | produces in the position different from the healthy part echo, it determines with the thinning part 17 existing in the test | inspection site | part 14. FIG.

Further, the two-dimensional distribution of the amplitude of the inspection portion echo is obtained from the relationship between the amplitude value of the inspection portion echo that changes corresponding to the movement distance of the transmission side probes 11 and 12 and the movement distance of the transmission side probes 11 and 12. Ask for. If the thinned portion 17 does not exist in the examination site 14, the two-dimensional distribution of the amplitude of the examination portion echo becomes the two-dimensional distribution of the amplitude of the healthy portion echo. If the thinning portion 17 exists in the examination site 14, the inspection portion echo The two-dimensional amplitude distribution is different from the two-dimensional amplitude distribution of the sound part echo. Accordingly, the distribution (two-dimensional distribution) of the thinned portion 17 is obtained from the change in the two-dimensional distribution of the amplitude of the inspection portion echo within the inspection portion 14.
In order to obtain the distribution (two-dimensional distribution) of the thinned portion 17, it is necessary to scan the ultrasonic probes 11 and 12 in at least two orthogonal directions on the surface of the inspection site 14 of the plate material 13. That is, the scanning direction of the ultrasonic probes 11 and 12 on the surface of the inspection site 14 of the plate material 13 is determined, the first to third steps are executed, and the X direction measurement is performed. The transmission side probe 11 and the reception side probe 12 are arranged so that the direction of the line connecting the reception side probe 12 and the scanning direction of the ultrasonic probes 11 and 12 in the X direction measurement is parallel. The Y-direction measurement is performed by performing the first to third steps so that the scanning direction of the ultrasonic probes 11 and 12 is arranged on the surface of the inspection site 14 and is orthogonal to the scanning direction in the X-direction measurement. And the distribution (two-dimensional distribution) of the thinning part 17 is calculated | required by superimposing the result of a X direction measurement, and the result of a Y direction measurement. In the X direction measurement and the Y direction measurement, if the distance Ys between the transmission side probe 11 and the reception side probe 12 is the same, the first step in the Y direction measurement can be omitted.

Here, when the transmission side probe 11 and the reception side probe 12 are arranged on the surface of the inspection site 14, the thinning portion 17 becomes the central portion of the transmission side probe 11 and the reception side probe 12. In this manner, the positions of the transmission side probe 11 and the reception side probe 12 are adjusted so that the thinning portion 17 is generated (whether the thinning portion 17 exists on the front side or the back side of the inspection site 14). ) And the case of measuring the thinning depth will be described. For example, as shown in FIG. 4A, when the thinned portion 17 exists on the back surface of the examination site 14, as shown in FIG. 5A, the transmission side is set so that the skip count S is an even number. Even if the interval Ys between the probe 11 and the receiving probe 12 is adjusted, as shown in FIG. 5 (B), the inspection part echo hardly occurs between Ws and W _−1s of the healthy part echo. As shown in FIG. 4A, when the interval Ys between the transmitting probe 11 and the receiving probe 12 is adjusted so that the number of skips is an odd number, as shown in FIG. Since the inspection portion echo is generated between Ws and W _−1s of the healthy portion echo, the generation position of the _thinned portion 17 can be determined.

For example, as shown in FIG. 6, the depth d is formed on the back surface of the inspection site 14 on the path of ultrasonic waves transmitted from the transmission side probe 11 and received by the reception side probe 12 through the inspection site 14. When the thinned portion 17 is present, the ultrasonic wave reflected on the surface of the examination site 14 is incident on the back surface of the examination site 14 at the reflection angle θ and reflected on the surface of the examination site 14 at the reflection angle θ. The skip is an alternative to skipping the ultrasonic wave that is reflected on the surface of the examination site 14 and is incident on the bottom surface of the thinned portion 17 at the reflection angle θ ′ and reflected on the surface of the examination site 14 at the reflection angle θ ′. At this time, the path of the inspection part echo is shortened by 2 t / cos θ−2 (t−d) / cos θ ′ with respect to the path of the healthy part echo. The difference is the difference Δ between the occurrence position of the examination part echo and the occurrence position of the healthy part echo. The thickness t is a known value, the values of Δ are obtained from the measurement, and θ and θ ′ are values determined by the path length Ws (the number of skips S) and the interval Ys, so the depth d of the thinned portion 17 is d = (1-cos θ ′ / cos θ) t−Δcos θ ′ / 2
Can be obtained from

As shown in FIGS. 7A, 7B, and 7C, the thinning detection device 26 used in the thinning detection method according to the second embodiment of the present invention is a tube material that is an example of a subject. The configuration of the measuring jig 29 is compared with the thinning detection apparatus 10 used in the thinning detection method according to the first embodiment. Are different. For this reason, only the measurement jig 29 will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.

The measurement jig 29 is provided on each side of the arm 30 that can be refracted at the center and can be fixed at an arbitrary refraction angle, and holds the transmitting probe 11 and the receiving probe 12. A probe holder 31 for urging the contact surfaces 24a and 24b of the transmitting probe 11 and the receiving probe 12 toward the surface of the inspection site 28 of the tube material 27 with a constant pressing force, and each probe A pair of wheels 32 which are attached to the side of the holder 31 and have their axles oriented in a direction parallel to a line segment connecting the transmitting probe 11 and the receiving probe 12, and the rotational speed of one of the wheels 32 And an encoder (not shown) for measuring the movement distance of the arm 30 and outputting a measurement signal to the analysis means 18.

Here, each probe holder 31 has a probe holding portion 33 for holding the transmission side probe 11 (reception side probe 12) in the central portion, and each probe holding portion 33 in the central portion. A V block 34 that is rotatably accommodated and has both side portions in contact with the surface of the inspection site 28 of the tube material 27 and both sides of the arm 30, and the probe holding portion 33 faces the surface of the inspection site 28 of the tube material 27. And an urging mechanism 35 that abuts the contact surface 24a of the transmission-side probe 11 (contact surface 24b of the reception-side probe 12) on the surface of the inspection site 28 by urging with a constant pressing force. is doing.

With such a configuration, the transmission side probe 11 and the reception side probe 12 can be held in contact with the surface of the inspection site 28 of the tube material 27 via the contact medium, and the inspection site 28 is also provided. A line segment connecting the transmitter-side probes 11 and 12 with the transmitter-side probe 11 and the receiver-side probe 12 maintained at a constant distance between the transmitter-side probes 11 and 12. It is possible to move in a direction orthogonal to.

Further, one of the transmission side probe 11 and the reception side probe 12 shown in FIG. 7, for example, a probe holder 31 holding the reception side probe 12, is used as a reference, and the transmission side probe 11. When the V block 34 of the probe holder 31 holding the probe is moved on the surface of the inspection site 28, the arm 30 also rotates with reference to the probe holder 31 holding the receiving probe 12 As the arm 30 rotates, the probe holder 33 attached to both sides of the arm 30 via the biasing mechanism 35 also rotates. For this reason, the directions of the transmitting probe 11 and the receiving probe 12 can be changed in accordance with the movement of the probe holder 31.

Thereby, the transmission side probe 11 and the reception side probe 12 are arranged so that the line segment connecting the transmission side probe 11 and the reception side probe 12 is parallel to the axial direction of the tube material 27, The transmission side probe 11 and the reception side probe 12 can be moved in the circumferential direction of the tube material 27, and it can be determined whether or not a thinned portion is generated in the circumferential direction of the tube material 27. Further, the transmission side probe 11 and the reception side probe 12 are arranged so that the line segment connecting the transmission side probe 11 and the reception side probe 12 is orthogonal to the axial direction of the tube material 27, and the transmission side probe The probe 11 and the receiving probe 12 can be moved in the axial direction of the tube material 27, and it can be determined whether or not a thinned portion is generated in the axial direction of the tube material 27. Further, the transmission side probe 11 and the reception side probe 12 are arranged so that the line segment connecting the transmission side probe 11 and the reception side probe 12 intersects the axial direction of the tube material 27, and the transmission side probe By moving the probe 11 and the receiving probe 12 in a spiral manner on the surface of the tube material 27, the tube material 27 can be inspected simultaneously in the circumferential direction and the axial direction to determine whether or not a thinned portion has occurred.
The thinning detection method according to the second embodiment of the present invention can be performed in the same manner as the thinning detection method according to the first embodiment, and thus detailed description thereof is omitted.

Example 1
As shown in FIG. 8 (A), an artificial thinning portion having a diameter of 4 mm and a depth of 4 mm was formed in the central portion on the back side of a plate member having a length of 400 mm, a width of 100 mm, and a thickness of 15 mm. Then, as shown in FIG. 8 (A), a pair of transverse wave oblique probes that are 300 mm apart from each other along the longitudinal direction are arranged at one position 1 in the width direction of the plate material on the surface of the plate material. Using the transverse wave oblique angle probe as the transmitting side probe and the other transverse wave oblique angle probe as the receiving side probe, as shown in FIG. The sound part echo was obtained by skipping the number of times and receiving the ultrasonic wave reaching the receiving probe.

Next, on the surface of the plate material, the transmission side probe and the reception side probe are kept at a constant distance between the transmission side probe and the reception side probe from position 1 to position 4 in FIG. Ultrasonic waves that enter the plate from the transmitter probe and propagate through the plate while moving and moving in the direction perpendicular to the line connecting the transmitter and receiver probes (width direction of the plate) Was received by the probe on the receiving side, and the inspection part echo was obtained.
Obtained while the transmitting probe and the receiving probe move from position 1 to the position before position 2 in FIG. 8A and through position 2 to position 4 on the surface of the plate. The generation position of the inspection part echo to be obtained coincides with the generation position of the healthy part echo obtained at position 1, and the generation of the inspection part echo obtained when the transmission side probe and the reception side probe reach position 2 Only the position was different. FIG. 9 (A) shows the inspection portion echo obtained when the transmitting side probe and the receiving side probe are arranged at position 2 in FIG. 8 (A) superimposed on the healthy portion echo. Further, FIG. 9B shows the inspection portion echo obtained when the transmission side probe and the reception side probe are arranged at position 3 in FIG. 8A and superimposed on the healthy portion echo. FIG. 9C shows a two-dimensional distribution of the amplitude of the inspection portion echo.

From FIG. 9A, when a thinned portion exists on the ultrasonic path reaching the receiving probe from the transmitting probe, the inspection echo is generated at a position different from the position where the sound echo is generated. I understand that On the other hand, from FIG. 9B, it can be seen that if the thinning portion does not exist on the path of the ultrasonic wave that reaches the receiving probe from the transmitting probe, the inspection echo and the healthy echo match. . Further, from the distribution diagram of FIG. 9C, the striped pattern corresponding to the inspection part echo in the place where the thinned part does not exist is the same as the striped pattern corresponding to the healthy part echo, and the thinned part exists in the place. The occurrence of a striped pattern is observed at a location different from the striped pattern corresponding to the sound part echo. Therefore, a sound part echo determined in advance corresponding to the thickness of the examination part is obtained, and compared with the examination part echo obtained by the examination of the examination part, if the occurrence position of the examination part echo is different, the thinned part in the examination part is reduced. It can be determined that there is a part.

(Example 2)
As shown in FIG. 10 (A), an artificial thinning portion having a diameter of 8 mm and a depth of 8 mm was formed at the center of the back side of a plate member having a length of 400 mm, a width of 100 mm, and a thickness of 15 mm.
Then, as shown in FIG. 10 (A), a pair of transverse wave oblique angle probes is arranged at a position 1 on one side of the plate material in the width direction on the surface of the plate material at a distance of 300 mm along the longitudinal direction. Using the transverse wave oblique angle probe as the transmitting side probe and the other transverse wave oblique angle probe as the receiving side probe, as shown in FIG. The sound part echo was obtained by skipping the number of times and receiving the ultrasonic wave reaching the receiving probe.

Next, the distance between the transmitting probe and the receiving probe is kept constant from position 1 to position 4 in FIG. Ultrasonic waves that enter the plate from the transmitter probe and propagate through the plate while moving and moving in the direction perpendicular to the line connecting the transmitter and receiver probes (width direction of the plate) Was received by the probe on the receiving side, and the inspection part echo was obtained.
It is obtained while the transmitting side probe and the receiving side probe move from the position 1 to the position before the position 2 in FIG. The generation position of the inspection section echo coincides with the generation position of the healthy section echo obtained at position 1, and the generation position of the inspection section echo obtained when the transmission side probe and the reception side probe reach position 2. Only different. FIG. 11 (A) shows the inspection portion echo obtained when the transmitting side probe and the receiving side probe are arranged at position 2 in FIG. 10 (A) superimposed on the healthy portion echo. Further, FIG. 11B shows the inspection portion echo obtained when the transmitting side probe and the receiving side probe are arranged at position 3 in FIG. 10A and superimposed on the healthy portion echo. FIG. 11C shows a two-dimensional distribution of the amplitude of the inspection portion echo.

From FIG. 11A, when a thinned portion exists on the ultrasonic path from the transmitting probe to the receiving probe, the inspection unit echo is generated at a position different from the position where the sound portion echo is generated. I understand that On the other hand, from FIG. 11B, it can be seen that if there is no thinning part on the ultrasonic path from the transmitting probe to the receiving probe, the inspection part echo matches the sound part echo. . Also, from the distribution diagram of FIG. 11C, the striped pattern corresponding to the inspection part echo in the place where the thinned part does not exist is the same as the striped pattern corresponding to the healthy part echo, and the thinned part exists in the place. The occurrence of a striped pattern is observed at a location different from the striped pattern corresponding to the sound part echo. Therefore, a sound part echo determined in advance corresponding to the thickness of the examination part is obtained, and compared with the examination part echo obtained by the examination of the examination part, if the occurrence position of the examination part echo is different, the thinned part in the examination part is reduced. It can be determined that there is a part.

Further, from the comparison between FIG. 9A and FIG. 11A and the comparison between FIG. 9C and FIG. 11C, the healthy part echo and the inspection part echo in the case where the thinned part having a depth of 4 mm exists. It can be seen that the difference in the generation position is smaller than the difference in the generation position between the sound part echo and the inspection part echo when the thinned portion having a depth of 8 mm exists. Therefore, it can be seen that the depth of the thinned portion can be known by obtaining the difference between the occurrence positions of the sound portion echo and the inspection portion echo.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above-described embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included.
For example, the difference in the occurrence position of the healthy part echo and the inspection part echo was used for the determination of the presence or absence of the thinned part in the third step. In addition to the difference in the generation position, the height of the inspection part echo can be taken into consideration. Thereby, it can be determined that the thinned portion is present at a place other than the central portion of the receiving side probe from the transmitting side probe, and that the thickness of the inspection site is thin as a whole.

10: Thinning detector, 11: Transmitter probe, 12: Receiver probe, 13: Plate material, 14: Inspection site, 15: Measuring jig, 16: Ultrasonic flaw detector, 17: Thinning part , 18: analysis means, 19: rod member, 20a, 20b: probe holder, 21: wheel, 22: encoder, 23a, 23b: signal cable, 24a, 24b: contact surface, 25a, 25b: probe case , 26: thinning detection device, 27: tube material, 28: inspection site, 29: measurement jig, 30: arm, 31: probe holder, 32: wheel, 33: probe holding unit, 34: V block , 35: biasing mechanism, 36: specimen

Claims (8)

A transverse wave oblique angle probe, which becomes a pair of ultrasonic transmitting and receiving probes with a predetermined interval, is disposed on the surface of a test body having a healthy thickness of an inspection site, and A first step of obtaining a sound portion echo by receiving ultrasonic waves reaching the receiving probe by performing a plurality of skips that enter the specimen from the transmitting probe and reflect on the back and front;
The transmitting probe and the receiving probe are arranged on both sides of the inspection region with the interval, and a plurality of light beams that enter the inspection region from the transmitting probe and reflect on the back and front sides. A second step of skipping times and receiving an ultrasonic wave reaching the receiving probe to obtain an inspection portion echo;
Compare the occurrence position of the healthy part echo obtained in the first step and the inspection part echo obtained in the second step, and determine the presence or absence of a thinned part occurring in the examination site from the difference A thinning detection method, comprising: a third step. 2. The thinning detection method according to claim 1, wherein in the determination of the presence or absence of a thinned portion in the third step, in addition to the difference in the occurrence position of the healthy portion echo and the inspection portion echo, the height of the inspection portion echo is high. The thinning detection method characterized by performing also in consideration. The thinning detection method according to any one of claims 1 and 2, wherein the thinning portion is detected at a central portion of the transmitting probe and the receiving probe. Meat detection method. 4. The thinning detection method according to claim 3, wherein the interval is set to a distance at which an ultrasonic wave reaches the receiving probe through the odd number of skips, and the reduction occurring on the back surface of the inspection site. A thinning detection method characterized by detecting a meat part. The thinning detection method according to claim 3, wherein the interval is set to a distance at which an ultrasonic wave reaches the receiving probe through the skip of the even number of times, and the reduction occurring on the surface of the inspection site is performed. A thinning detection method characterized by detecting a meat part. In the thinning detection method of any one of Claims 1-5, the depth of the said thinning part is calculated | required from the difference of the generation | occurrence | production position of the said healthy part echo and the said test | inspection part echo. Detection method. The thinning detection method according to any one of claims 1 to 3, wherein incident angles of the transmitting probe and the receiving probe are the same, and are 45 degrees or more and 75 degrees or less, respectively. A method for detecting thinning, characterized by using an object. In the thinning detection method according to any one of claims 1 to 7, the transmitting probe and the receiving probe on the surface of the inspection site, the spacing being kept constant, A thinning detection method, wherein the range of the thinning portion is measured by moving in a direction orthogonal to a line segment connecting between the transmitting side probe and the receiving side probe.

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