JP7300383B2 - LAMINATED PEELING INSPECTION METHOD AND PEELING INSPECTION APPARATUS - Google Patents

Description

The present invention relates to a peel inspection method and a peel inspection apparatus for a laminate. More specifically, an ultrasonic wave is incident on the laminate from a transducer of a probe arranged on one side of the laminate in which a plurality of members are laminated, and multiple reflected waves from the laminate are received. The present invention relates to a laminate peel inspection method and peel inspection apparatus for inspecting the presence or absence of delamination by evaluating reflected waves.

Conventionally, many of the laminates to be inspected for peeling as described above are pipes, containers, etc. At the time of inspection, a person enters the inside of the pipes, containers, etc., and visual inspection, hammering inspection, pinhole inspection, etc. are performed from the inside. was normal. Therefore, a lot of time was required for the inspection.

Therefore, the applicant of the present application invented a peeling inspection method as described in Patent Document 1. This method obtains the echo height fluctuation range for each number of reflections of multiple reflected waves, including fluctuations due to various factors that cause echo height fluctuations, in each of the sound part and the simulated peeling part of the laminate, and determines the soundness of the obtained sound. A region where the variation ranges of the part and the simulated peeling part do not overlap is obtained, the number of reflections of the reflected wave that is greater than the minimum number of reflections in the obtained region and the height of the region is a predetermined value or more is obtained, and the laminate is obtained. The presence or absence of delamination is inspected by comparing the echo height of the reflected wave of the predetermined number of reflections in the inspected portion with the echo height of the reflected wave of the same number of reflections in the healthy portion.

By the way, the size of delamination to be detected is generally larger than the area (diameter) of the transducer of the probe to be used. However, when detecting flaking smaller than the area of the vibrator, Patent Document 1 does not mention the size of flaking to be detected, and does not disclose any method for detecting flaking smaller than the area of the vibrator. not In addition, in fields such as semiconductors, there is an increasing need for detecting delamination that is smaller than the vibrator size.

Japanese Patent No. 5624250

In view of such conventional circumstances, it is an object of the present invention to provide a peel inspection method and a peel inspection apparatus for a laminate that can detect even a peel having a size smaller than the vibrator size.

In order to achieve the above object, the peeling inspection method for a laminate according to the present invention is characterized in that an ultrasonic wave is incident on the laminate from a transducer of a probe arranged on one side of the laminate in which a plurality of members are laminated. In addition, in the method of inspecting the presence or absence of delamination by receiving multiple reflected waves from the laminate and evaluating the received multiple reflected waves, the method includes: A separation echo height of a reflected wave reflected at a predetermined number of times is obtained, and a relative sound echo height to the separation echo height in a sound portion of the laminate is obtained, and the relative sound echo height and the area of the vibrator are calculated. Based on the relationship, a relative echo height corresponding to the size of the delamination to be detected is obtained, a reference echo height of the delamination is set based on the relative echo height, and the probe uses Multiple reflected waves are received in the inspection section of the laminate, and the echo height of the reflected waves of the predetermined number of reflections in the multiple reflection waves in the inspection section is compared with the reference echo height to determine the delamination. It is to inspect the presence or absence of

If the area of the peeled portion is equal to the area of the transducer of the probe used (100% peeled), the echo height of the peeled portion of the laminate can be said to be entirely due to the peeled portion. On the other hand, since there is no peeled portion (0% peeled) in the sound portion of the laminate, the echo height is not caused by the peeled portion. Since the echo height of the reflected ultrasonic wave is proportional to the reflection area, the echo height (relative echo height) in the healthy portion with respect to the echo height in the peeled portion and the area of the vibrator are given in FIG. There is a correlation as shown in b).
According to the above configuration, the peel echo height of the reflected wave reflected at the predetermined number of reflections among the multiple reflected waves at the peeled portion of the laminate is obtained in advance, and the relative soundness to the peel echo height at the healthy portion of the laminate is obtained. Obtain the echo height, obtain the relative echo height corresponding to the size of the delamination to be detected based on the relationship between the relative sound echo height and the area of the transducer, and determine the delamination based on the relative echo height. Since the reference echo height is set, it is possible to set the size (minimum dimension for detection) of the peeled portion to be detected. Then, since the echo height of the reflected wave of the predetermined number of reflections in the inspection part and the set reference echo height are compared, even delamination smaller than the area (diameter) of the vibrator can be evaluated. be able to.

By the way, the inside of the delamination to be detected may be filled with gas such as air. Therefore, in the above configuration, the peeled portion is a portion in which a gap formed at the interface between adjacent members is filled with gas, and the peel echo height is based on the reflected wave from the interface with the gas. should be When the cleaved portion is filled with gas, almost 100% of the reflected wave (echo height) at the cleaved portion is reflected, so that it is hardly attenuated by reflection. On the other hand, in the sound portion, part of the ultrasonic wave is transmitted through the laminate, and the reflected wave (echo height) is attenuated by reflection. Therefore, it is possible to evaluate delamination that is smaller than the area (diameter) of a vibrator filled with gas such as air.

In this case, if the member located on the side away from the probe among the adjacent members in the sound portion is regarded as a liquid, and the relative sound echo height is based on the reflected wave from the interface with the liquid good. As shown in FIG. 4, since the attenuation of water is smaller than that of other materials, the difference in relative echo height between a liquid such as water and a gas such as air is the smallest. Therefore, assuming that the material of the sound portion is a liquid such as water, the echo height of the reflected wave from the interface with the liquid is obtained as the relative healthy echo height with respect to the separation echo height of the reflected wave from the interface with the gas. This relative sound echo height has a smaller difference from the separation echo height than the relative sound echo heights of other materials. Therefore, as shown in FIG. 8, the detection level can be increased by reducing the difference between the relative healthy echo height and the separation echo height.

In any one of the above configurations, before the multiple reflected waves are received by the inspection unit, the plate thickness of the laminate is measured over the entire surface of the inspection unit to identify the corroded portion, and the corroded portion is detected by the inspection unit. It is preferable to set the part excluding the part as the part to be inspected. As a result, it is possible to detect (specify) in advance a small corroded portion (a portion where the wall thickness is reduced) that is difficult to clearly detect with the echo of the reflected wave of the predetermined number of reflections among the multiple reflected waves. can improve the accuracy of the entire inspection.

On the other hand, the delamination to be detected may be filled with a liquid such as water rather than a gas such as air. Therefore, in the above configuration, the separation portion is a portion in which a gap formed at the interface between adjacent members is filled with liquid, and the separation echo height is based on the reflected wave from the interface with the liquid. should be By determining the separation echo height based on the reflected wave from the interface with the liquid, it is possible to determine the presence or absence of delamination even in a portion where the gap is filled with the liquid (for example, a corroded portion).

Preferably, the probe is scanned along the one side, and a scanned image is generated based on echo heights of the reflected waves of the predetermined number of reflections in the inspection section. As described above, attention is paid to the reflected wave that has been reflected a predetermined number of times, so that the scanned image can be easily generated and the inspection efficiency can be improved.

In order to achieve the above object, the laminate peel inspection apparatus according to the present invention is characterized in that an ultrasonic wave is incident on the laminate from one side of the laminate in which a plurality of members are laminated, and multiple reflections from the laminate are performed. In a configuration that includes a probe having a transducer that receives waves and a signal processing device that evaluates received multiple reflected waves, and inspects for the presence or absence of delamination by evaluating the received multiple reflected waves, the signal The processing device obtains in advance the peeling echo height of the reflected wave reflected by a predetermined number of times among the multiple reflected waves at the peeled portion of the laminate, and compares the peeling echo height at the healthy portion of the laminate. Obtaining a relative sound echo height, obtaining a relative echo height corresponding to the size of the delamination to be detected based on the relationship between the relative sound echo height and the area of the transducer, and obtaining the relative echo height The reference echo height of the delamination is set based on, the probe receives multiple reflected waves at the inspection portion of the laminate, and the predetermined number of reflections of the multiple reflected waves at the inspection portion The present invention is to inspect the presence or absence of the delamination by comparing the echo height of the reflected wave of (1) with the reference echo height.

The signal processing device may generate a scanned image from multiple reflected waves received by scanning the probe. Examples of scanned images include B-scan images and C-scan images. Further, the probe may be a single transducer type probe, or may be a dual transducer type probe. Also, it is possible to use a water immersion probe using a water tank for peeling inspection of small parts.

According to the characteristics of the peel inspection method and the peel inspection apparatus for a laminate according to the present invention, it is possible to detect even peel with dimensions smaller than the dimensions of the vibrator.

Other objects, configurations and effects of the present invention will become apparent from the following detailed description of the invention.

1 is a schematic diagram of a peel inspection apparatus according to the present invention; FIG. It is a figure explaining the behavior of the ultrasonic wave with respect to each layer of a laminated body, (a) is a sound part, (b) is a figure which shows peeling in a 1st interface, (c) is a figure which shows peeling in a 2nd interface. FIG. 4 is a diagram schematically showing variations in echo height in a healthy portion, a peeled portion, and a corroded portion; FIG. 4 is a diagram showing changes in sound pressure reflectance of multiple reflected waves; It is a figure explaining comparison of the peak time of a reflected wave, and a peak value. FIG. 4 is a diagram for explaining setting of a peeling area to be detected, in which (a) is a diagram showing changes in the sound pressure reflectance of multiple reflected waves, and (b) is a diagram showing the relationship between the peeling area and the relative echo height. . It is a figure equivalent to Drawing 6 in a second embodiment. FIG. 6B is a view equivalent to FIG. 6B for explaining a modified example of the first embodiment;

Next, the first embodiment of the invention will be described in more detail with reference to FIGS. 1-6.

(Inspection device configuration)
As shown in FIG. 1, a peel inspection apparatus 1 according to the present invention generally includes a first member 20 and a second member 30 as a plurality of members, which are laminated on one side 11 of a laminate 10 with a thin layer 40 interposed therebetween. A probe 2 equipped with a transducer 2a for injecting an ultrasonic wave from the laminate 10 into the laminate 10 and receiving multiple reflected waves from the laminate 10, and a signal processing device 3 for processing and evaluating the received multiple reflected waves. Prepare. A position detector 2b such as an encoder for detecting the scanning position is attached to the probe 2 and connected to the signal processing device 3 . The signal processing device 3 may be configured by a personal computer, for example.

The signal processing device 3 causes the probe 2 to generate ultrasonic pulses by controlling the pulser 4a. The transmitted ultrasonic pulse passes through (or passes through) the first and second members 20 and 30 and the thin layer 40 and is reflected by the interfaces F1 and F2 and received by the probe 2 . The received multiple reflected waves are amplified by the receiver 4b and the preamplifier 5, and converted into digital signals by the A/D converter 7 after noise is removed by the filter 6. FIG. Then, the signal is processed by the signal processing device 3 and displayed on the display 8 . The display 8 displays, for example, a graph in which the horizontal axis is the time axis representing the propagation distance and the vertical axis is the intensity of the reflected wave. Note that these can also be implemented as the flaw detector 9 .

In addition, the signal processing device 3 processes the received signal together with the scanning position data of the probe 2 detected by the position detector 2b, generates a scanning image such as a B-scan image or a C-scan image, and displays it on the display 8. display. Furthermore, the signal processing device 3 further comprises a warning device 3a for warning the presence of delamination.

(Laminate structure)
In this embodiment, as shown in FIGS. 1 and 2, the laminate 10 to be inspected is roughly composed of a plate material as a first member 20 and an adhesive layer made of an adhesive as a thin layer 40 on the plate material 20. and a lining material as the second member 30 that is adhered via. A coating film 50 is formed on the surface 21 of the plate material 20 (one side 11 of the laminate 10).

The film thickness of the coating film 50 may vary by, for example, several tens to several hundreds of μm depending on the state of construction and aging. Regardless of the material of the coating film, the greater the film thickness, the greater the decrease in the echo height.

Furthermore, the factor that causes the echo height of the reflected wave to fluctuate is not limited to the film thickness of the coating film 50 . For example, the state of contact of the probe 2 with the laminated body 10 is also a factor that causes the echo height to fluctuate. The contact state is a concept that includes the inclination and pressing force of the probe with respect to the object, the thickness and type of the couplant, and the like. In addition, there are other fluctuation factors such as roughness of the surface and interface of the layered product and contents in the peeled portion.

FIG. 3 schematically shows variations in echo height including the above variation factors. As described above, the signal of the reflected wave includes a range of variation due to the above various factors. As the number of reflections increases between the sound portion and the peeled portion, the difference between the reflection signal fluctuation range R0 of the sound portion and the reflection signal fluctuation range R1 of the peeled portion increases. This is because the sound pressure reflectance of the air present in the peeled part is almost 1 and does not change much, but in the sound part the sound pressure reflectance at the interface is less than 1. This is because they are accumulated and become large. The difference in the variation range (the height d1 of the region where the variation range R0 of the healthy portion and the variation range R1 of the peeled portion do not overlap) excludes the variation due to the above factors. Therefore, by obtaining the number of reflections N, which is the difference in the variation range of a predetermined value or more, and focusing on the echo height of the reflected wave of the number of reflections N, the influence of the above-mentioned variation factors can be eliminated, and the peeled portion and the healthy portion can be separated. signals can be clearly distinguished, and detection accuracy is improved.

By the way, since the ultrasonic wave is scattered on the corroded surface, the more the corrosion progresses (the larger the surface roughness), the greater the attenuation, and the echo height becomes smaller than that of the sound portion. The signal of the corroded portion (thickened portion whose thickness is reduced by corrosion) also includes fluctuations due to the above factors. Therefore, in the corroded portion, similarly to the above, the number of reflections N that results in a difference in the variation range of a predetermined value or more (the height d2 of the region where the variation range R0 of the healthy portion and the variation range R2 of the corroded portion do not overlap) is obtained, Attention should be paid to the echo height of the reflected wave of the number N of reflections. Details of the determination of the number of reflections are disclosed in Japanese Patent No. 5624250 of the present applicant.

(Behavior of multiple reflected waves)
Here, the relationship between the behavior of ultrasonic waves and the reflected waveform will be described.
FIG. 2(a) shows the behavior of reflection in a sound portion where the plate material 20, the lining material 30 and the adhesive layer 40 are in close contact with each other and there is no peeling. Ultrasonic waves incident from the probe 2 into the inside of the plate member 20 from the upper surface 21 are partially formed at the second interface F2, which is the interface between the lower surface 22 of the plate member 20 and the upper surface 41 of the adhesive layer 40, as indicated by P2. reflect.

On the other hand, the ultrasonic wave transmitted through the second interface F2 propagates through the adhesive layer 40 and reaches the first interface F1, which is the interface between the lower surface 42 of the adhesive layer 40 and the upper surface 31 of the lining material 30 . Here, when the acoustic impedances of the lining material 30 and the adhesive layer 40 are similar (the difference in acoustic impedance between the lining material 30 and the adhesive layer 40 is small), little reflection occurs at the first interface F1. Therefore, the reflected wave indicated by symbol P1 is hardly received. Therefore, the received waveform due to multiple reflections in the sound portion is mainly formed by the reflected wave P2 from the second interface F2.

FIG. 2(b) shows behavior of reflection when peeling occurs at the first interface F1. Since the peeled portion D1 is irrelevant to the reflection at the second interface F2, it reflects at the second interface F2 as indicated by P2 in the same manner as the healthy portion. On the other hand, an interface between the adhesive layer 40 and the air A is formed at the separation portion D1. Therefore, unlike the sound portion, most of the ultrasonic waves transmitted through the second interface F2 are reflected at the interface between the adhesive layer 40 and the air A as indicated by P1'. Therefore, the received waveform due to multiple reflection when the peeled portion D1 exists is a waveform obtained by adding the reflected wave P1' from the peeled portion D1 and the reflected wave P2 from the second interface F2.

FIG. 2(c) shows behavior of reflection when peeling occurs at the second interface F2. An interface between the plate member 20 and the air A is formed at the separation portion D2. Therefore, most of the ultrasonic waves reaching the second interface F2 are reflected at the interface between the plate member 20 and the air A as indicated by P2', and no reflected waves are generated at the first interface F1. Therefore, the received waveform due to multiple reflection when the peeled portion D2 exists is almost formed by the reflected wave P2' from the peeled portion D2. Here, the sound pressure reflectance of the air A between the plate member 20 and the peeled portion D2 is approximately 1, and does not change much even if the reflection is repeated. On the other hand, the reflected wave P2 from the sound portion is attenuated by reflection at the second interface F2 because the sound pressure reflectance between the plate member 20 and the adhesive layer 40 forming the second interface F2 is less than 1.

FIG. 4 shows variations in sound pressure reflectance of various materials. The vertical axis represents the relative echo height (dB) (difference in intensity of the echo from the healthy portion with respect to the echo from the peeled portion), and the horizontal axis represents the number of reflections. Although the sound pressure reflectance varies depending on the material, it is smaller than the sound pressure reflectance of air, which is 1, and the difference increases as the number of reflections increases. In other words, by using the difference between the sound pressure reflectance of air and the sound pressure reflectance of various materials (the sound pressure reflectance of air is 1 and that of other materials is smaller), it is possible to detect the presence or absence of delamination. be.

(Difference in received waveform)
Here, the difference in received waveforms between the healthy portion and the peeled portions D1 and D2 will be described.
The tendency of attenuation (attenuation coefficient) due to multiple reflections is as follows: the second peel test piece TP2 having the configuration as shown in FIG. 2(c); ) is larger in the order of sound test specimen TP0 having the configuration shown in FIG. Further, when the attenuation tendency of the sound test sample TP0 is used as a reference, the second peel test sample TP2 has a larger difference in sensitivity than the first peel test sample TP1, and the difference in attenuation due to multiple reflection is larger.

The reflected wave P2 of the healthy test piece TP0 is attenuated by reflection at the second interface F2 and transmission through the adhesive layer 40. FIG. On the other hand, since almost 100% of the reflected wave P2' of the second peel test piece TP2 is reflected at the interface with the air A of the peeled portion D2, attenuation due to transmission does not occur unlike the normal test piece TP0. In addition, since the second peel test piece TP2 does not pass through the adhesive layer 40, it is not affected by attenuation due to the adhesive layer 40. FIG. Therefore, attenuation due to reflection at the interface of the second peel test piece TP2 (peeled portion D2) is smaller than that of the sound test piece TP0. As shown in FIG. 5, the echo height H2 in the signal waveform S2 caused by the peeled portion D2 of the second interface F2 is significantly larger than the echo height H0 of the signal waveform S0 in the healthy portion. Therefore, the peeled portion D2 can be detected by comparing the peak values (echo heights) of the reflected waves reflected multiple times.

On the other hand, the waveform of the first peel test piece TP1 is the sum of both the reflected wave P1' from the peeled portion D1 and the reflected wave P2 from the second interface F2. Since the reflected wave P1' of the first peel test piece TP1 is reflected by the air A in the peeled portion D1, the influence of attenuation due to reflection is small. However, since the reflected wave P1' is transmitted through the adhesive layer 40 and is attenuated thereby, it is smaller than the peak value (echo height) of the waveform of the second peel test piece TP2 but larger than the waveform of the sound test piece TP0. As shown in FIG. 5, the echo height H1 in the signal waveform S1 caused by the peeled portion D2 of the second interface F2 is greater than the echo height H0 of the signal waveform S0 in the healthy portion. Therefore, by comparing the peak values (echo heights) of the reflected waves reflected multiple times, the peeled portion D1 can also be detected.

In the case of the peeled portion D1 of the first interface F1, the peak time T1 of the reflected wave that repeats the predetermined number of reflections in the signal waveform S1 is the peak time T1 of the reflected wave that repeats the same number of reflections in the signal waveform S0 of the healthy portion. It appears later than the peak time T0, resulting in a time lag ΔT. This is because attenuation due to reflection at the interface of the sound portion is greater than that of the peeled portion D1, so that when the reflection is repeated a plurality of times, the reflected wave from the peeled portion D1 becomes relatively large, and the waveform of the sound portion is timed. This is because the waveform is deviated. On the other hand, in the case of the peeled portion D2 of the second interface F2, the peak time T2 in the signal waveform S2 is substantially the same as the peak time T0 of the healthy portion. This is because both reflected waves are reflected at the second interface F2. Therefore, the peeled portion D1 can also be detected by comparing the propagation times of the reflected waves reflected multiple times. Details of the peeled portion detection based on the peak time shift ΔT are disclosed in Japanese Patent No. 5735706 of the present applicant.

(Oscillator area and echo height)
By the way, the echo height H of the reflected wave described above is based on the premise that the peeled portion D is larger than the diameter L (area) of the transducer 2a of the probe 2, and the size of the peeled portion D is taken into consideration. not However, delamination smaller than the diameter L of the vibrator 2a may exist in the inspection area E. In the case of such a small detachment, it cannot be correctly evaluated simply by comparing the echo heights.

Here, for example, when the reflected wave is reflected 15 times at the interface, point A in FIG. 6A represents the reflectance at the interface between steel and air. This corresponds to the second interface F2 between the plate material 20 and the air in the peeled portion D2 where the plate material 20 and the lining material 30 are separated, as shown in FIG. . On the other hand, point B in the figure represents the reflectance at the interface between steel and polyethylene. This corresponds to the first interface F1 of the sound portion where the plate material 20 and the lining material 30 are in close contact with each other, and shows the reflectance in the state of 0% peeling.

When the transducer 2a with a diameter of 10 mm is used as the probe 2, the peeled area of 100% peeling at point A is the peeled diameter of 10 mm, which is the same as the area of the transducer 2a. On the other hand, point B is 0% peeling and the peeling area is zero. Since the reflected echo height of the ultrasonic wave is proportional to the reflection area, if the horizontal axis is the reflection area (exfoliation area) and the vertical axis is the relative echo height at points A and B, the correlation shown in FIG. indicates

As shown in FIG. 6B, when the transducer 2a with a diameter of 20 mm is used as the probe 2, the peeling area that gives the echo height of 100% peeling is a peeling with a diameter of 20 mm. Therefore, for example, when a peeling with a diameter of 10 mm or more is to be detected by the transducer 2a with a diameter of 20 mm, the relative echo height caused by the peeling with a diameter of 10 mm can be known from the above correlation. By setting the reference echo height of delamination based on this relative echo height K, it is possible to set the size of the delaminated portion to be detected (minimum dimension for detection). Even a small peeled portion can be detected with high accuracy. Since the reference echo height can be set according to the relative echo height K, the size of the peeling to be detected can be arbitrarily set. Although the figure shows an example of 15 reflections, the same applies to other reflections. Moreover, the same applies not only to polyethylene but also to other materials.

(Evaluation method)
Next, a peeling inspection method (evaluation of interlayer peeling) of the laminate 10 will be described below.
First, the size of the delamination portion to be detected (minimum dimension for detection) is determined in advance, and as shown in FIG. (A in the figure) and relative healthy echo height (B in the figure) to the separation echo height in the sound portion of the laminate 10 are obtained. Then, based on the relationship between the obtained relative sound echo height B and the diameter of the transducer 2, a relative echo height (K in the figure) corresponding to the size of the delamination to be detected is obtained. Based on the echo height K, a reference echo height for delamination is set. These results are stored in the signal processing device 3 .

As the predetermined number of reflections, for example, as described above, it is preferable to use the number of reflections N at which the height d1 of the region where the variation range R0 of the sound portion and the variation range R1 of the peeled portion do not overlap is equal to or greater than a predetermined value. . Here, the echo height (attenuation curve) of the multiple-reflected waves in the healthy portion differs depending on the material of the lining material 30 . Therefore, when the material of the lining material 30 is unknown or when the lining material 30 has been changed (changed) due to repair or the like, the number of times of reflection N may not be set accurately.

As shown in FIG. 4, since water has less attenuation than other materials, the difference in relative echo height between water and air is the smallest. Therefore, regarding water as a lining material, the variation range of the reflected signal due to the interface (healthy portion) between the plate 20 and the water 30 and the variation range of the reflected signal due to the interface (peeled portion) between the plate 20 and the air are It is preferable to obtain the number of reflections N at which the height d of the region where the two do not overlap is equal to or greater than a predetermined value. As a result, the number of reflections N can be set without considering the material of the lining material 30, and the detection accuracy of the peeled portion is also improved.

In determining the number of reflections, for example, a portion corresponding to the healthy portion and a portion corresponding to the peeled portion in the laminate 10 are selected. In addition, the "healthy part" and the "peeled part" may be the sound test body TP0, the first peel test body TP1, and the second peel test body TP2 as described above, or other devices or other devices corresponding to these test bodies. can also be used. Furthermore, for example, a simulated peel test piece (comparative test piece) prepared by simulating a peeled portion may be compared with a portion selected as a portion corresponding to a healthy portion in the laminate. In this way, since both the "healthy part" and the "peeled part" are "parts", they include "an arbitrary part of the laminate 10 to be inspected" and "a test separate from the laminate 10". Both "body (piece) and other equivalent devices or members" are included. In addition to the above method, for example, in the case of a laminate having a curvature, an echo height correction value corresponding to the curvature may be obtained to correct the sensitivity.

Next, prior to the inspection of the predetermined inspection portion E of the laminate 10, the thickness of the plate material 20 is measured over the entire surface of the inspection portion E. As shown in FIG. For example, the plate thickness of the plate 20 is measured by applying ultrasonic waves to the plate 20 from the surface 21 and scanning the probe 2 to measure the ultrasonic wave propagation time to the second interface F2 of the plate 20. The thickness measurement method is not particularly limited, but by using ultrasonic flaw detection, the peel inspection apparatus can be used in common and the inspection efficiency is good. Furthermore, by performing plate thickness measurement before peeling detection, the portion where the thickness of the plate material 20 is reduced first can be specified as a corroded portion (thickness portion), and can be evaluated separately from the peeled portion. Inspection accuracy is also improved. In particular, it is possible to detect and evaluate even small corrosion that is difficult to detect and flat thinned portions with smooth spreads such as mortar linings as corroded portions. In the case of an object to be inspected in which such a corroded portion (a portion where the thickness is reduced) does not occur, the plate thickness measurement may be omitted.

Next, in the inspection section E excluding the portion specified as the corroded portion in the previous plate thickness measurement, the probe 2 is scanned along the surface 21 of the plate material 20 and ultrasonic waves are incident to receive multiple reflected waves. Then, the echo height of the reflected wave that repeats the same number of reflections as the set number of reflections in the multiple reflected waves is obtained. Then, the echo height is compared with the previously set reference echo height, and if the echo height is greater than the reference echo height, it is evaluated that there is a dissection portion having a size equal to or larger than the set detection minimum dimension.

In addition, the peak time T as the propagation time of the reflected wave that repeats the same number of reflections as the number of reflections set above is also obtained. Then, by comparing the peak time and the reference peak time, peeling at the first interface F1 between the lining material 30 and the adhesive layer 40 or peeling at the second interface F2 between the plate material 20 and the adhesive layer 40 is determined.

Further, a predetermined threshold value (amplitude) is set in the signal processing device 3 in advance with respect to the reference echo height (peak value), and when the peak value exceeds the predetermined value, the warning device 3a warns. good too. Furthermore, the multiple reflected waves may be processed together with the scanning position data of the probe 2 of the position detector 2b to generate a scanning image such as a B-scan image or a C-scan image together with the signal waveform or independently. These images may indicate the presence or absence of peeling. In the conventional method of focusing on the attenuation curve of the multiple reflected waves, it is difficult to distinguish between the signals of the healthy portion and the exfoliated portion because the multiplexed signal changes with the movement of the probe. Further, in the method of analyzing data after scanning, the analysis processing is enormous and various factors affect the signal, so the accuracy is also lowered. On the other hand, since the present invention focuses on the echo height of the reflected wave of the predetermined number of times of reflection, the signal can be easily generated with simple signal processing.

Here, when comparing the peak time and echo height, the above-mentioned predetermined number of times is set to the number of times that allows comparison of the peak time and echo height with respect to the waveform in the healthy part, taking into account the attenuation coefficient. As described above, the attenuation tendency in the sound portion differs from the attenuation tendency in the case where the peeled portion D exists. Therefore, for example, in the signal processing device 3, the number of times may be set so that the echo height of the reflected wave in a healthy portion such as a test piece is displayed with an intensity of about 20% of 100% amplitude display, as shown in FIG. As a result, each reflected echo from the peeled portion of the first and second interfaces F1 and F2 in the inspected portion E can be distinguished from the healthy portion. Of course, the sensitivity may be adjusted as appropriate.

Next, a second embodiment of the invention will be described with reference to FIG. In addition, the same code|symbol is attached|subjected to the member similar to the said embodiment.
In the above-described first embodiment, the case where the peeling portions D1 and D2 are filled with air (gas) has been described as an example, but the peeling portions may be filled with water (liquid).

Therefore, in the present embodiment, unlike the first embodiment, the separation echo height at the separation portion of the laminate 10 is not reflected by the interface with air (A in FIG. 6), but is reflected from the interface with water. (C in FIG. 7). For example, B' in FIG. Then, a reference echo height for delamination is set based on the healthy echo height K'. As a result, even when the inside of the peeled portion is filled with water, it can be detected as a peeled portion by distinguishing it from a healthy portion. Therefore, for example, in a situation where the object to be inspected is a tank, pipe, or the like that is in operation (operating) and water may enter the peeled portion, inspection can be performed during operation. Even if the interior of the thinned portion whose thickness has been reduced due to corrosion or the like is filled with a liquid such as water, the thinned portion can be similarly detected.

However, since the relative echo height of polyethylene (B in FIG. 6) is closer to the relative echo height of water (C in the figure) compared to other materials, the peeled portion filled with water and the healthy portion It becomes difficult to distinguish the echo height of Therefore, the second embodiment can be preferably carried out if the material (for example, fluororesin, hard rubber, etc.) has a relative echo height that can be distinguished from the relative echo height of water.

Finally, the possibilities of other embodiments of the invention will be discussed.
In the above-described first embodiment, the separation echo height (A in FIG. 6) at the peeled portion of the laminate 10 is obtained, and the relative healthy echo height ( B) was sought. However, as shown in FIG. 8, the relative sound echo height (B in FIG. 8) is obtained by using water (liquid) as the lining material 30 (second member) and its sound portion (first member 20 and water). The relative sound echo height (C in the figure) with respect to the separation echo height in the state of close contact with each other may be obtained. As shown in the figure, when the relative echo height is K'', the detectable peeling area with water in the φ20 oscillator is φ10, but it is larger than φ10 in polyethylene. By regarding the lining material 30 (second member) as water (liquid) in this way, the peeling inspection can be performed even if the lining material 30 (second member) is unknown, for example. In addition, there is no need to prepare sound test pieces depending on the object to be inspected, and convenience (inspection efficiency) is also improved.

In each of the above-described embodiments, the probe 2 is a single-element probe that also serves for transmission and reception. However, a dual transducer type probe in which transmission and reception are separate units may be used. Further, in each of the above-described embodiments, ultrasonic waves are transmitted and received by directly pressing the probe 2 against the surface 21 of the first member 20, but the water immersion method is also applicable.

In the above embodiment, the material (material) of the first member (plate material) 20 of the laminate 10 to be inspected is not particularly limited. Any material can be used. Moreover, the laminated body 10 to be inspected may be a container such as a tank or a container, or may be a constituent part of a pipe. Furthermore, the material of the second member (lining material) 30, like the first member 20, is not particularly limited as long as it is a transmitting substance of ultrasonic waves. It can be applied to various lining materials such as resin. Of course, it is not limited to the lining material. That is, the plurality of members may be any combination of dissimilar materials and homogeneous materials.

Moreover, in the above embodiment, the laminate 10 is formed by laminating the first and second members 20 and 30 with the adhesive layer 40 interposed therebetween. However, the number of members to be laminated is not particularly limited, and may be three or more layers. In addition, the adhesive layer 40 may be interposed at least partially between the plurality of members constituting the laminate 10. For example, the adhesive layer 40 may be a brazing agent for brazing or a surface layer portion of one of the adjacent members. It may be a denatured portion or the like obtained by denaturing a portion. It is possible to detect peeling of the upper and lower surfaces 41 and 42 of the adhesive layer 40 . As the material of the adhesive layer 40, a material that approximates the acoustic impedance of a member located adjacent to the adhesive layer 40 and away from the incident position of the ultrasonic waves can be selected. In the sound portion, if the reflected wave P1 from the interface F1 between the member and the adhesive layer 40 is close enough to be difficult to detect, it is possible to detect the presence or absence of peeling by comparing the propagation time with the sound portion. Because it becomes On the other hand, unlike the former, it is possible to select a material for the adhesive layer 40 whose acoustic impedance does not approximate. In such a case, a difference in the attenuation of the reflected wave at the interface of the adhesive layer 40 is likely to occur, and the presence or absence of peeling can be detected by comparing the echo height with that of the healthy portion.

Further, in each of the above-described embodiments, a substantially flat flaw detection surface has been described as an example, but the present invention can also be applied to a laminate having a curved surface. In the case of a curved surface, since ultrasonic waves are scattered and reflected on the surface and interface of the laminate, attenuation increases as the number of reflections increases. However, if both the healthy portion and the inspected portion are curved surfaces having the same curvature, the influence of the curvature will be canceled out. Therefore, it is possible to detect the presence or absence of peeling in a member having a curved surface such as a pipe.

In each of the embodiments described above, the laminate 10 having the coating film 50 has been described as an example. However, as described above, the variation in the thickness of the coating film 50 is only one example of the variation factor of the echo height of the reflected wave. Therefore, the laminate 10 to be inspected is not limited to those having the coating film 50 , and even the laminate 10 without the coating film 50 can be similarly inspected.

Although the embodiments of the present invention are configured as described above, more comprehensively, the peel inspection method and peel inspection apparatus for a laminate may have the following configurations.

In the peeling inspection method described in the above-mentioned Patent Document 1, the echo height of the reflected wave of the number of reflections obtained in advance in the inspection part of the laminate is compared with the echo height of the reflected wave of the same number of reflections in the healthy part. Existence of delamination is inspected. Therefore, it is necessary to obtain the reference echo height of the sound portion for each type of lining material, which is complicated. In addition, in the conventional method, when there is a corroded part (thickness part) where the thickness (plate thickness) of the member is reduced due to corrosion, etc., the ultrasonic wave is scattered and reflected by the corroded surface, so the sound part that serves as a reference Corrosion was determined to exist when the echo height of the inspected portion was smaller than the echo height. However, depending on the shape of the corrosion, the echo height of the inspected portion may not always be smaller than the echo height of the healthy portion, and there is a possibility that the corrosion cannot be detected.

In view of the above-described conventional circumstances, an object of the invention having the configuration described below is to provide a peel inspection method and peel inspection apparatus for a laminate that can further improve the detection accuracy of the peeled portion.

In order to achieve the above object, the peeling inspection method for a laminate is characterized in that an ultrasonic wave is incident on the laminate from a transducer of a probe arranged on one side of the laminate in which a plurality of members are laminated, and the laminate A peeling inspection method for a laminate for inspecting the presence or absence of delamination by receiving multiple reflected waves from a body and evaluating the received multiple reflected waves, Reflected waves are received respectively, and in each of the sound portion and the peeled portion, a variation range of echo height is obtained for each reflection number of multiple reflected waves including variation due to various factors that cause variations in echo height, and these variations The number of times of reflection of the reflected wave in which the height of the area where the ranges do not overlap is a predetermined value or more is obtained, and the first member positioned on one side of the laminate is detected by the probe in the inspection unit of the laminate. Receive ultrasonic waves from the first member and receive reflected waves from the first member, measure the plate thickness of the first member from the propagation time of the reflected waves, and reduce the thickness of the first member A thinned portion is specified, and then multiple reflected waves are received by the probe at an inspection portion excluding the thinned portion from the inspection portion of the laminate, and the number of times of reflection of the multiple reflected waves is determined. A peeling inspection method for a laminate for inspecting the presence or absence of the interlayer peeling based on the echo height of a reflected wave.

By the way, the echo height (signal intensity) of the reflected wave reflected at the interface of the laminate to be inspected depends on, for example, the presence or absence of a coating film, its thickness, the contact state of the probe with the flaw detection surface, the flaw detection surface and interface It fluctuates depending on factors such as the surface roughness of the peeled portion and the substance in the peeled portion. Therefore, focusing only on the attenuation rate and attenuation curve of the entire multiple-reflected wave, it may be difficult to clearly distinguish between the signal from the sound portion and the signal from the peeled portion due to fluctuations due to the above factors.
For example, as shown in FIG. 3, the echo height of the reflected wave includes variations (variations) due to the various factors described above. According to the above configuration, the multiple reflected waves are received in advance at the healthy portion and the peeled portion of the laminate, respectively, and the multiple reflected waves including fluctuations due to various factors that cause variations in the echo height are received in each of the healthy portion and the peeled portion. In addition to determining the echo height variation range for each number of times of reflection, the number of reflections of the reflected wave in which the height of the area where the variation ranges do not overlap is equal to or greater than a predetermined value is determined. Since the presence or absence of delamination is inspected based on the echo height of the reflected wave of the inspection portion of the obtained number of reflections, fluctuations due to the above factors can be eliminated, and the presence or absence of delamination can be detected with high accuracy.
Moreover, in the inspection part of the laminate, the ultrasonic wave is made incident on the first member located on one side of the laminate by the probe, and the reflected wave from the first member is received, and from the propagation time of the reflected wave The plate thickness of the first member is measured to identify corroded portions where the thickness of the first member is reduced. As a result, the thinned portion can be specified before the inspection for the presence or absence of delamination, and can be evaluated separately from the delamination, thereby improving the inspection accuracy. In addition, it is possible to detect small thickness reductions that are difficult to detect, as well as flat thickness reduction portions that spread smoothly, improving inspection accuracy.

In the above configuration, the echo height of the reflected wave of the same number of times of reflection among the multiple reflected waves at the inspection portion of the laminate body excluding the reduced thickness portion is the echo height of the reflected wave of the same number of reflections at the peeled portion. The presence or absence of the delamination may be inspected by comparing with the echo height. Since the echo height of the peeled portion is used as a reference, there is no need to change the test piece or test sensitivity for each material of the members of the laminate, and the inspection accuracy is improved.

In this case, the variation range of the echo height of the multiple reflected waves in the healthy portion is based on the reflected waves from water, and the variation range of the echo height of the multiple reflected waves in the peeled portion is based on the reflected waves from the air. It should be based on As shown in FIG. 4, since the attenuation of water is smaller than that of other materials, the difference in echo height between water and the peeled portion is the smallest. Therefore, by assuming that the sound portion is water as in the above configuration, there is no need to change the test piece and test sensitivity for each material of the members of the laminate, and the inspection accuracy is improved. Further, for example, delamination can be detected regardless of whether or not the lining material is difficult to identify or whether or not the lining material has been repaired.

Further, in the above configuration, the separation echo height of the reflected wave reflected at the number of times of reflection among the multiple reflected waves at the peeled portion of the laminate is obtained in advance, and the separation echo height at the healthy portion of the laminate is obtained. a relative echo height corresponding to the size of the delamination to be detected is obtained based on the relationship between the relative sound echo height and the area of the transducer, and the relative echo height The reference echo height of the delamination is set based on the thickness, and the echo of the reflected wave of the number of times of reflection among the multiple reflected waves at the inspection portion excluding the thinned portion from the inspection portion of the laminate. The presence or absence of the delamination may be inspected by comparing the height with the reference echo height.

According to the above configuration, the peel echo height of the reflected wave reflected at the predetermined number of reflections among the multiple reflected waves at the peeled portion of the laminate is obtained in advance, and the relative soundness to the peel echo height at the healthy portion of the laminate is obtained. Obtain the echo height, obtain the relative echo height corresponding to the size of the delamination to be detected based on the relationship between the relative sound echo height and the area of the transducer, and determine the delamination based on the relative echo height. Since the reference echo height is set, it is possible to set the size (minimum dimension for detection) of the peeled portion to be detected. Since the echo height of the reflected wave of the predetermined number of times among the multiple reflected waves in the inspection section is compared with the set reference echo height, even if the delamination is smaller than the area (diameter) of the vibrator, the accuracy is high. can be evaluated.

In any one of the above configurations, it is preferable to scan the probe along the one side and generate a scanned image based on echo heights of the reflected waves of the number of reflections in the inspection section. Focusing attention on the reflected wave that has been reflected a predetermined number of times, it is possible to easily generate a scanned image and improve the inspection efficiency.

In order to achieve the above object, the laminate peel inspection apparatus according to the present invention is characterized in that an ultrasonic wave is incident on the laminate from a transducer of a probe arranged on one side of the laminate in which a plurality of members are laminated. In addition, a peeling inspection apparatus for a laminate for inspecting the presence or absence of delamination by receiving multiple reflected waves from the laminate and evaluating the received multiple reflected waves, wherein the signal processing apparatus is provided in advance with the Multireflected waves are received at the sound portion and the peeled portion of the laminated body, respectively, and each of the sound portion and the peeled portion echoes each time the multiple reflected waves are reflected, including variations due to various factors that cause variations in echo height. In addition to obtaining the height variation range, the number of reflections of the reflected wave in which the height of the area where these variation ranges do not overlap is a predetermined value or more is obtained. An ultrasonic wave is incident on a first member located on the side and a reflected wave from the first member is received, the plate thickness of the first member is measured from the propagation time of the reflected wave, and the first Identify the thinned portion where the thickness of the member is reduced, and then receive multiple reflected waves at the inspection portion excluding the thinned portion from the inspection portion of the laminate with the probe, and the multiple reflection A peeling inspection apparatus for a laminate that inspects the presence or absence of the interlayer peeling based on the echo height of the reflected wave of the number of reflections in the wave.

In the above configuration, the signal processing device may generate a scanned image from multiple reflected waves received by scanning the probe. Examples of scanned images include B-scan images and C-scan images. Further, the probe may be a single transducer type probe, or may be a dual transducer type probe.

INDUSTRIAL APPLICABILITY The present invention can be used, for example, as a laminate peel inspection method and apparatus for inspecting peeling at each interface of thin layers interposed between members in a storage container or pipe as a laminate in which a plurality of members are laminated. can do. For example, it can be applied to detect delamination in different material laminates such as adhesion between CFRP material and aluminum and adhesion between aluminum and copper. Furthermore, it can be applied to brazing aluminum and steel, brazing turbine blades and stellite (heat-resistant alloy), soldering aluminum to aluminum, and the like.

1: peeling inspection device, 2: probe, 2a: vibrator, 2b: position detector, 3: signal processing device, 3a: warning device, 4a: pulser, 4b: receiver, 5: preamplifier, 6: filter, 7: A/D converter, 8: display, 9: flaw detector, 10: laminate, 11: one side, 12: other side, 20: first member (plate material), 21: upper surface, 22: lower surface, 30 : second member (lining material), 31: upper surface, 32: lower surface, 40: thin layer (adhesive layer), 41: upper surface, 42: lower surface, 50: coating film, A: peeling echo height, B: relative soundness Echo height, d1, 2: height of region, D1, 2: separation part, E: inspection part, F1: first interface, F2: second interface, H0 to 2: echo height (peak value), K : relative echo height, L: transducer diameter, P1, 2, P1', 2': ultrasonic waves, S0-2: signal waveform, T0-2: peak time, ΔT: time shift, R0: fluctuation of healthy part Range, R1: Variation range of peeled portion, R2: Variation range of corroded portion

Claims (8)

An ultrasonic wave is incident on the laminate from the transducer of the probe arranged on one side of the laminate in which a plurality of members are laminated, and the multiple reflected waves from the laminate are received, and the received multiple reflected waves are evaluated. A laminate peel inspection method for inspecting the presence or absence of delamination by
In advance, the separation echo height of the reflected wave reflected at a predetermined number of times among the multiple reflected waves at the peeled portion of the laminate is obtained, and the relative sound echo height with respect to the separation echo height at the sound portion of the laminate is obtained. looking for
Obtaining a relative echo height corresponding to the size of the delamination to be detected based on the relationship between the relative healthy echo height and the area of the transducer,
setting a reference echo height of the delamination based on the relative echo height;
receiving multiple reflected waves at the inspection portion of the laminate with the probe;
A peeling inspection method for a laminate, wherein the presence or absence of the interlayer peeling is inspected by comparing the echo height of the reflected wave of the predetermined number of reflections in the inspecting section with the reference echo height. 2. A separation echo height is based on a reflected wave from the interface with the gas, wherein the separation portion is a portion in which a gap formed at an interface between adjacent members is filled with gas. A method for inspecting peeling of a laminate. 2. A member positioned away from said probe among adjacent members in said sound portion is regarded as a liquid, and said relative sound echo height is based on a reflected wave from an interface with said liquid. A method for inspecting peeling of a laminate described above. 2. The peeling portion is a portion in which a gap formed at an interface between adjacent members is filled with a liquid, and the peeling echo height is based on a reflected wave from the interface with the liquid. A method for inspecting peeling of a laminate. Before the multiple reflected waves are received by the inspection unit, the plate thickness of the laminate is measured over the entire surface of the inspection unit to identify the corroded portion, and the portion of the inspection unit excluding the corroded portion is inspected. The peel inspection method for a laminate according to any one of claims 1 to 4, wherein the peel inspection method is a target portion. 6. The scanning image according to any one of claims 1 to 5, wherein the probe is scanned along the one side, and the scanning image is generated based on the echo height of the reflected wave of the predetermined number of reflections in the inspection section. A peel inspection method for a laminate. A probe having a vibrator for injecting an ultrasonic wave from one side of a laminated body in which a plurality of members are laminated into the laminated body and receiving multiple reflected waves from the laminated body, and evaluating the received multiple reflected waves A delamination inspection device for a laminate that inspects the presence or absence of delamination by evaluating the received multiple reflected waves, comprising a signal processing device that
The signal processing device obtains in advance a peeling echo height of a reflected wave reflected at a predetermined number of times among the multiple reflected waves at the peeled portion of the laminate, and obtains the peeling echo height at the healthy portion of the laminate. Find the relative sound echo height to the height,
Obtaining a relative echo height corresponding to the size of the delamination to be detected based on the relationship between the relative healthy echo height and the area of the transducer,
setting a reference echo height of the delamination based on the relative echo height;
The probe receives multiple reflected waves at the inspection portion of the laminate, and compares the echo height of the reflected waves of the predetermined number of reflections among the multiple reflected waves at the inspection portion with the reference echo height. A delamination inspection apparatus for a laminate for inspecting the presence or absence of the delamination. 8. A laminate peeling inspection apparatus according to claim 7, wherein said signal processing device generates a scanning image from multiple reflected waves received by scanning said probe.

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