JP2015099164A - Ultrasonic test equipment and ultrasonic flaw detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic test equipment with which the detection result can be obtained with high accuracy even if the surface of an object to be inspected is formed to have complicated shape.SOLUTION: An ultrasonic test equipment has an ultrasonic wave probe 1 for making ultrasonic wave enter an object 2 to be inspected by driving a plurality of ultrasonic wave elements and receiving the reflective ultrasonic wave from the object 2 to be inspected and analysis means 7 for analyzing reception signals receiving the reflective ultrasonic wave by the ultrasonic wave probe 1 and calculates the result of test. The analysis means 7 calculates the result of test by using a transmission route of ultrasonic wave determined based on the surface information of the object 2 to be inspected in which the ultrasonic wave is incident.

Description

The present invention relates to an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method for confirming the soundness of an inspection object in a nondestructive manner.

In general, the ultrasonic flaw detection technique is a technique that can confirm the soundness of a structural material that is a non-destructive inspection target, and is used as an indispensable technique in various fields. In particular, in recent years, there is a demand for inspection even for a structure in which a surface to be inspected has a complicated shape portion such as a curved surface shape, and the demand for ultrasonic flaw detection technology is increasing.

On the other hand, when a complicated shape such as a curved surface is formed on the surface of the inspection object, there is a problem that ultrasonic waves cannot be incident on the inspection object appropriately. Incidentally, in the weld line and its heat-affected zone, distortion and umbrella breakage due to heat input of welding, convex shape after depositing molten metal, etc., complex parts such as curved surfaces where the design is flat Are often formed.

In addition, for example, various pipes typified by nozzle nozzles of nuclear power plants and thermal power plants, and platform sections of turbine blades are designed to have complicated shapes such as curved surfaces, and there are many places where inspection is difficult. Existing. Under the present circumstances, there is a problem that an ultrasonic wave cannot be incident on an inspection object, or even if it can be incident, a target flaw detection refraction angle may not be achieved. Also, phased array (PA) and matrix array (
When MA) is used, the shape of the surface may be different for each incident position of each element.

As means for solving such a problem, there is a technique described in Patent Document 1, for example. This technique describes a method of measuring the surface shape of an inspection object with an ultrasonic probe and optimizing the transmission delay time of the phased array (PA) in accordance with the measured shape.

JP 2007-170877 A "Ultrasonic Flaw Detection Apparatus and Method"

Ultrasonic defect dimension measurement -New development of nondestructive inspection-

However, the technique described in Patent Document 1 described above depends on the surface shape of the inspection target,
It only mentions optimizing the ultrasound delay time conditions. Specifically, by entering ultrasonic waves according to the surface shape, it is possible to cope with the problem that the incident angle of the ultrasonic waves changes, but when displaying the flaw detection results, If the flaw detection result is displayed without considering the influence, an instruction echo of a defect is detected at a location different from the actual flaw detection position.

If the position of this indication echo is not corrected for the flaw detection result considering the influence of the surface shape separately,
An accurate defect position cannot be detected, an error in the detected position occurs, and only ultrasonic flaw detection with low accuracy can be performed. In addition, there is a problem that the instruction echo becomes unclear.

The present invention has been made in consideration of the above-described circumstances, and provides an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method capable of obtaining a highly accurate detection result even when the surface of an inspection object is formed in a complicated shape. The purpose is to do.

In order to achieve the above object, an ultrasonic flaw detection apparatus according to the present invention drives a plurality of ultrasonic elements, and calculates the incident angle calculated in advance based on the positional relationship between the ultrasonic probe and the inspection object and the condition to be flawed. The ultrasonic probe that injects ultrasonic waves into the inspection object and receives the reflected ultrasonic waves from the inspection object, and the analysis that calculates the flaw detection result by analyzing the reception signal that the ultrasonic probe receives the reflected ultrasonic waves An ultrasonic flaw detection apparatus comprising: the inspection object on which the ultrasonic wave is incident separately from the pre-calculated incident angle of the ultrasonic wave by the ultrasonic element. An incident angle that is actually incident is calculated based on the surface shape information, and a flaw detection result is calculated using the propagation path of the ultrasonic wave according to the incident angle that is actually incident.

In addition, the ultrasonic flaw detection method according to the present invention is calculated in advance by driving a plurality of ultrasonic elements of the ultrasonic probe and calculating in advance based on the positional relationship between the ultrasonic probe and the inspection object and the condition to be flawed. An ultrasonic wave incident step for injecting ultrasonic waves to the inspection object at an incident angle, an ultrasonic wave reception step for receiving reflected ultrasonic waves from the inspection object after the ultrasonic wave incident step, and an ultrasonic wave reception step And an analysis step of calculating a flaw detection result by analyzing a reception signal when the ultrasonic probe receives the reflected ultrasonic wave, wherein the analysis step includes the ultrasonic element using the ultrasonic element. Separately from the pre-calculated incident angle of the sound wave, the incident angle that is actually incident is calculated based on the surface shape information of the inspection object on which the ultrasonic wave is incident. And calculating the flaw detection results by using the ultrasonic wave propagation path due to the incident angle is.

According to the present invention, even when the surface to be inspected is formed in a complicated shape, a highly accurate detection result can be obtained, and accurate ultrasonic flaw detection can be performed.

1 is a block diagram showing an embodiment of an ultrasonic flaw detector according to the present invention. It is explanatory drawing which shows the example of a general flaw detection. It is explanatory drawing which shows the example which reconfigure | reconstructs a general flaw detection result. It is a flowchart which shows the general flaw detection method. It is explanatory drawing which shows the propagation path of the ultrasonic wave whose surface to be examined is non-planar. It is explanatory drawing which shows the reconstruction method which does not consider the surface shape of a test object. It is explanatory drawing which shows the reconstruction method which considered the surface shape of test object. It is a flowchart which shows the case where a surface shape is measured and a flaw detection result is reconfigure | reconstructed. It is a flowchart which shows the case where a flaw detection result is reconfigure | reconstructed according to the surface shape read from design data. It is explanatory drawing which shows the state which the ultrasonic wave oscillated in this embodiment propagates inside test object. It is explanatory drawing which shows the case where an actual incident angle and a flaw detection refraction angle are calculated using surface inclination (theta) of a test object. 6 is a flowchart for associating a received signal with inspection target position information. It is explanatory drawing for calculating | requiring the surface inclination of a test object. It is explanatory drawing for calculating | requiring the surface inclination of a test object by another method. It is a figure which shows the image of the example which performed the reconstruction which did not consider the surface shape of a test object. It is a figure which shows the image of the example reconfigure | reconstructed in consideration of the surface shape of a test object. It is a figure which shows the intensity | strength of an ultrasonic wave by sound field simulation. It is a figure which shows the intensity | strength of an ultrasonic wave by sound field simulation. It is a figure which shows the image of the result of having reconfigure | reconstructed without considering the influence of the curved surface shape of a surface. It is a figure which shows the image of the result reconfigure | reconstructed in consideration of the influence of the curved surface shape of the surface.

  Embodiments of an ultrasonic flaw detector according to the present invention will be described below with reference to the drawings.

The ultrasonic probe in the present embodiment refers to a piezoelectric element that can generate ultrasonic waves by a piezoelectric effect using a ceramic, its composite material, or other materials, a piezoelectric element using a polymer film, or other ultrasonic waves. A structure consisting of any of a mechanism capable of generating vibration, a damping material for damping ultrasonic waves, and a front plate attached to an ultrasonic transmission surface, or a combination of these, and a general ultrasonic probe It shall be called a child.

In this embodiment, a case where a so-called array sensor in which piezoelectric elements are arranged one-dimensionally is applied will be described. However, a matrix sensor arranged two-dimensionally may be applied.

The acoustic contact medium in the present embodiment is a medium capable of propagating ultrasonic waves, such as water, glycerin, machine oil, acrylic or polystyrene gel. In the present embodiment, the description of the acoustic contact medium may be omitted when ultrasonic waves are incident on the inspection object from the ultrasonic probe. The details of the flaw detection method using ultrasonic transmission / reception delay control by using a plurality of piezoelectric elements such as a general phased array are well-known techniques described in Non-Patent Document 1 and the like, and thus the description thereof is omitted.

  Hereinafter, a specific configuration of the ultrasonic flaw detector according to the present embodiment will be described.

FIG. 1 is a block diagram showing an embodiment of an ultrasonic flaw detector according to the present invention. FIG. 2 is an explanatory diagram showing a general flaw detection example. FIG. 3 is an explanatory diagram showing an example of reconstructing a general flaw detection result. FIG. 4 is a flowchart showing a general flaw detection method. FIG. 5 is an explanatory diagram showing an ultrasonic propagation path whose surface to be inspected is non-planar.

In the following description, a case will be described in which a pipe is an inspection target and a defective portion of the pipe is flaw-detected by ultrasonic waves. Moreover, in FIG. 1, the center of piping is shown with the dashed-dotted line.

As shown in FIG. 1, the ultrasonic flaw detector has an ultrasonic probe 1. The ultrasonic probe 1 drives a plurality of ultrasonic elements, enters ultrasonic waves through the acoustic contact medium 3 into a pipe that is the inspection object 2, and receives reflected ultrasonic waves from the inspection object 2.

Further, the ultrasonic flaw detection apparatus has an ultrasonic transmission / reception unit 4 for transmitting / receiving ultrasonic waves with the ultrasonic probe 1 and a drive element control for controlling an ultrasonic element actually driven by the ultrasonic transmission / reception unit 4. Unit 5, a signal recording unit 6 as a storage means for recording a reception signal (ultrasonic signal) received by the ultrasonic probe 1, and a received signal recorded in the signal recording unit 6 is analyzed to obtain a flaw detection result. An analysis unit 7 to calculate, a display unit 8 for displaying a flaw detection result obtained by the analysis unit 7, and a design database 9 in which data on the surface shape of the inspection object 2 at the design stage are recorded in advance. Prepare.

The drive element control unit 5 includes a transmission / reception sensitivity adjustment unit 5a that adjusts transmission / reception sensitivity, and constitutes delay means for oscillating each of the plurality of ultrasonic elements at an arbitrary time. The signal recording unit 6
Storage means for storing the ultrasonic signal received by the drive element control unit 5 is configured.

The analysis unit 7 constitutes an analysis unit that calculates a flaw detection result based on the propagation path of the ultrasonic wave obtained based on the surface information of the inspection object 2 on which the ultrasonic wave is incident. That is, the analysis unit 7 obtains the ultrasonic wave propagation path using the relative angle between the surface of the inspection object 2 at the position where the ultrasonic wave is incident and the ultrasonic probe 1.

The ultrasonic flaw detection apparatus shown in FIG. 1 may have another configuration as long as it has a mechanism for providing a delay time to the ultrasonic probe 1 composed of a plurality of piezoelectric elements and controlling transmission and reception. .

Next, a flaw detection method using a general phased array (PA) will be described with reference to FIGS.

As shown in FIG. 2, in order to make an ultrasonic wave enter the inspection object 2 at an arbitrary flaw detection refraction angle,
By applying an appropriate time delay to a plurality of ultrasonic elements (hereinafter also referred to as piezoelectric elements) provided in the ultrasonic probe 1 of the phased array (PA), the direction and focus of the ultrasonic waves are oscillated. Position control is possible. In the present embodiment, a case where the linear scan method is applied will be described as a representative. However, various flaw detection methods such as sector scan may be used.

When the ultrasonic wave incident on the inspection object 2 has a reflection source such as a defect inside the inspection object 2,
The ultrasonic waves are reflected and scattered, and the reflected waves are received by the piezoelectric element of the ultrasonic probe 1. The ultrasonic waveform obtained in this way depends on the set ultrasonic incident angle α and flaw detection refraction angle β.
It is possible to image in the electronic scan direction. This imaging is generally called B-scan or S-scan. This imaging is reconstructed with the incident angle α and the flaw detection refraction angle β according to the flaw detection conditions at the time of flaw detection as shown in FIG. In the following embodiments, B-
This will be described using scan.

  Such a general flaw detection method will be described with reference to FIG.

As shown in FIG. 4, the delay time is calculated based on the flaw detection conditions such as the flaw detection refraction angle β and the focal position with respect to the inspection object 2 (step S1), and the ultrasonic probe 1 is installed at a position where the inspection object 2 exists. (Step S2), and after inspection of the inspection object 2 (step S3), the inspection refraction angle β
The ultrasound data obtained according to the above is reconstructed to create a B-scan (step S4).
Thereafter, the inspection position of the inspection object 2 is changed again, and the processes in steps S3 and S4 are repeated.

However, for example, when the surface of the inspection object 2 has a weld metal surplus or waviness (partial curved surface) formed by grinding, or when the inspection object 2 is originally non-planar, FIG. Flaw detection and reconstruction of the results under the flaw detection conditions assumed in FIG.
When 4) is performed, there is a problem that an error occurs in the inspection result.

This problem will be described with reference to FIG. FIG. 5 shows a curved surface 2 a such as a wave on the surface of the inspection object 2.
It is a case where it inspects about the case where is formed. Here, when the flaw detection conditions are calculated under the condition of a plane as shown in FIG. 2, flaw detection is performed from any position of the ultrasonic probe 1 with the incident angle α. Therefore, when the surface of the inspection object 2 is incident on the portion formed on the curved surface 2a, the flaw detection refraction angle β is not fixed due to Snell's law, and various changes occur depending on the incident position. Therefore, when reconstruction is performed based on the ultrasonic wave reception signal, unless the surface shape of the inspection object 2 is taken into consideration, the flaw detection refraction angle β of the reconstruction condition is different from the actual flaw detection refraction angle β. Therefore, reconstruction is performed under conditions different from those of the ultrasonic wave propagation path.

  This point will be described in more detail with reference to FIGS.

FIG. 6 is an explanatory diagram showing a reconstruction method that does not consider the surface shape of the inspection object. FIG. 7 is an explanatory diagram showing a reconstruction method in consideration of the surface shape of the inspection object. Specifically, FIG. 6 and FIG.
Each of the flaw detection results is shown in B-scan, and the ultrasonic wave propagation path used for reconstruction calculation is shown. FIG. 6 shows an example in which the surface shape of the inspection object 2 is not considered, and FIG. 7 shows an example in which the surface shape of the inspection object is considered.

The example shown in FIG. 6 is an ultrasonic wave propagation path that assumes a planar shape to the last, and is reconfigured without reflecting the actual flaw detection refraction angle β in the inspection object 2. That is, since reconstruction is performed using an ultrasonic propagation path different from the actual one, the defect position obtained by the reconstruction causes an error with respect to the position of the defect actually occurring in the inspection object 2. .

On the other hand, as shown in FIG. 7, if reconstruction is performed using an ultrasonic propagation path that takes into account the actual surface shape of the inspection object 2 (that is, an actual ultrasonic propagation path), Such an error does not occur. Accordingly, the propagation path of the ultrasonic wave shown in FIG.
The flaw detection refraction angle β can be calculated from the incident angle α.

As described above, in the present embodiment, the flaw detection refraction angle β is calculated at each position of the incident point, and the flaw detection result is reconstructed according to the angle, thereby reflecting the actual ultrasonic flaw detection result, the position error, etc. This makes it possible to perform inspections without any problems.

Next, two processes for reconstructing the flaw detection result in consideration of the surface shape of the inspection object 2 are shown in FIG.
A description will be given with reference to FIG.

FIG. 8 is a flowchart showing a case where the surface shape is measured to reconstruct the flaw detection result. FIG. 9 is a flowchart showing a case where the flaw detection result is reconstructed according to the surface shape read from the design data.

In FIG. 8, in step S <b> 11, the ultrasonic probe 1 is placed on the inspection object 2 and the acoustic contact medium 3.
The inspection object 2 is scanned by installing via Next, in step S12, the surface shape of the inspection object 2 is measured. Then, ultrasonic flaw detection processing is executed by the ultrasonic probe 1 (step S).
13) After that, a reconstruction process of the flaw detection result according to the surface shape of the inspection object 2 measured in step S12 is performed (step S14).

In FIG. 9, in step S <b> 21, the ultrasonic probe 1 is placed on the inspection object 2 and the acoustic contact medium 3.
The inspection object 2 is scanned by installing via Next, in step S <b> 22, ultrasonic flaw detection processing is executed by the ultrasonic probe 1. And after performing the process (step S23) which reads the surface shape of the test object 2 previously recorded on the design database 9, the reconstruction process of the flaw detection result according to the surface shape is performed (step S24).

  Next, a method for calculating the flaw detection refraction angle β will be described with reference to FIGS.

FIG. 10 is an explanatory diagram showing a state in which the ultrasonic wave oscillated in the present embodiment propagates inside the inspection object. FIG. 11 is an explanatory diagram showing a case where the actual incident angle and flaw detection refraction angle are calculated using the surface inclination θ of the inspection object. FIG. 12 is a flowchart for associating the received signal with the inspection target position information.

As shown in FIG. 10, the positional relationship between the ultrasonic probe 1 and the inspection object 2 and the condition for flaw detection (the propagation direction of the ultrasonic wave inside the inspection object 2 and the ultrasonic wave are focused from the center position Em of the simultaneously transmitting elements. And the acoustic contact medium 3 is propagated at the incident angle αi calculated in advance by the information), and reaches the surface of the inspection object 2. The incident angle αi corresponds to the incident angle α shown in FIGS. 6 and 7, in other words, an angle at which ultrasonic waves are transmitted from the ultrasonic probe 1 to the inspection object 2. When the surface shape is not flat, the incident angle αi is different from the actual incident angle. Here, the center position Em of the element is position information of the ultrasonic element, and the incident angle α
i is an ultrasonic transmission angle.

As shown in FIGS. 10 and 12, first, coordinates S1 to S1 are formed on the surface of the inspection object 2 based on the result of measuring the surface shape of the inspection object 2 in advance or design information recorded in advance in the design database 9. Information on Sn is set. In addition, since this embodiment demonstrates the case where a phased array probe is used, each coordinate information is two-dimensional (S (x, z)), but when using a matrix array probe, it is tertiary. Set in the original (S (x, y, z)). (Step S
31)
Next, the center position Em of the ultrasonic element and the incident angle αi of the ultrasonic wave transmitted from each ultrasonic element
From this, it is possible to calculate the incident position (hereinafter also referred to as the incident point) Sm (x, z) of the ultrasonic wave transmitted from the center position Em of the ultrasonic element. (Step S32)
Here, as shown in FIG. 11, by using the surface inclination θ of the inspection object at the coordinates of the incident position Sm (x, z), the actual incident angle αm and the actual flaw detection refraction angle βm are calculated from Snell's law. Is possible. Note that the surface inclination θ is an inclination with respect to the surface of the inspection object 2 assumed to be a plane, in other words, a relative angle between the actual surface of the inspection object 2 and the ultrasonic probe 1 at the ultrasonic incident position. A method for calculating the surface inclination θ will be described later. (Steps S33, S34, S35)
As a result, the propagation distance Em from the center position Em of the transmitted ultrasonic element to the incident position Sm
Sm, a position Smmm (x, z) in the inspection object 2 from the incident position Sm, and the inspection object 2
Since the propagation direction of the ultrasonic wave can be known, the actual propagation path of the ultrasonic wave can be obtained.

Since the sound velocity of each of the acoustic contact medium 3 and the inspection object 2 is known, in the data of the ultrasonic signal Um transmitted and received from the element center position Em, each time of the ultrasonic signal is measured. It is possible to calculate which position in the inspection object corresponds to.
In addition, although illustration is abbreviate | omitted, the ultrasonic signal Um is a signal waveform which took signal amplitude on the vertical axis and time on the horizontal axis. (Step S36)
By repetitively executing this series of processes for all element positions where ultrasonic flaw detection is performed, reconstruction in consideration of the surface shape of the inspection object 2 can be performed.

Next, a method for obtaining the surface inclination θ of the inspection object 2 at the coordinate Sm described above will be described. FIG. 13 is an explanatory diagram for obtaining the surface inclination of the inspection object. FIG. 14 is an explanatory diagram for obtaining the surface inclination of the inspection object by another method. This surface inclination θ is a relative angle between the ultrasonic probe 1 and the inspection object 2.

As shown in FIG. 13, the surface inclination θ at the ultrasonic incident point Sm can be calculated from the coordinate point Sm−1 and the coordinate point Sm + 1 adjacent to the ultrasonic incident point Sm. It is also possible to calculate using the coordinate point Sm-a and the coordinate point Sm + a apart from the ultrasonic incident point Sm, not the adjacent coordinates.

Further, it is also possible to use a method of obtaining the inclination by using each point from the coordinate point Sm-a to the coordinate point Sm + a and performing linear approximation by a method such as a least square method so as to pass through each point. Further, as shown in FIG. 14, since there may be noise in the shape measurement result, the coordinate point Sm-a
The surface inclination θ may be calculated by removing data points having large variations among a plurality of points from the coordinate point Sm + a to the coordinate point Sm + a.

When the incident point Sm is specified from the center position Em of the ultrasonic element and the position Smmm in the inspection object 2, the surface inclination θ at each position of the surface shape function S is calculated first, The coordinates Sn to the coordinates Sn with respect to the position Em and a position Smmm in the inspection object 2
It is also possible to calculate by the Snell's law, and to calculate the value at which the absolute value of the calculation result is the minimum as the incident point Sm in the positional relationship between the center position Em and a certain position Smmm in the inspection object 2.

Further, the flaw detection result reconstruction area M (x, z) shown in FIG. 10 is created by calculating the position from the ultrasonic signal Um to the flaw detection result M and from the coordinate point of the flaw detection result M to each coordinate. Both methods of calculating the position of the corresponding ultrasonic signal Um can be applied.

Next, with regard to the reconstruction that does not consider the surface shape and the reconstruction that considers the surface shape, using the result of performing the flaw detection on the specimen to which the defect was actually given and reconstructing the obtained flaw detection signal Comparison will be described. FIG. 15 shows an example in which reconstruction is performed without considering the surface shape of the inspection object 2.
FIG. 16 shows an example in which reconstruction is performed in consideration of the surface shape of the inspection object 2. In these examples, flaw detection is performed under the condition that ultrasonic waves are transmitted from the curved surface (waviness) 2 a existing on the flaw detection surface of the inspection object 2 to the defect given to the inspection object 2.

FIG. 15 shows a result of flaw detection performed on the inspection object 2 having a swell under the condition that ultrasonic waves are incident on a plane at 45 degrees, and the flaw detection result is reconstructed without considering the influence of the curved surface shape.

In the example shown in FIG. 15, the peak indicating the corner echo portion (echo from the defect opening portion on the opposite side of the inspection surface of the inspection object 2) is located on the inner side of the surface opposite to the inspection surface. I understand that In addition, the defect end echo (echo from the end on the inner side of the defect inspection target)
Does not show a clear peak.

On the other hand, in the example shown in FIG. 16, it can be seen that the peak of the corner echo portion is located on the surface opposite to the flaw detection surface. Also, the end echo shows a clear peak.

Further, comparing FIG. 15 with FIG. 16, it can be seen that in the example shown in FIG. 15, a region showing an echo appears at a position where no defect or the like on the left side exists on the paper surface of the defect position.

As described above, in the reconstruction without considering the surface shape, the indication of the corner echo and the end echo of the defect given to the inside of the inspection object 2 affected by the curved surface is unclear and the position of the indication is actually given. It can be seen that an error is generated with respect to the defect position.

On the other hand, in the reconstruction result in consideration of the influence of the curved surface shape of the surface, the indication of the corner echo and the end echo of the defect is clearly shown as compared with FIG. 15, and the indication position of the defect is also accurate. It has been found.

By the way, in this embodiment mentioned above, there exists a problem that the flaw detection refraction angle (beta) changes with the positions of the ultrasonic wave which injects into the test object 2. FIG. Further, for example, when the curvature of the surface of the inspection object 2 as shown in FIGS. 10 to 14 is large, the flaw detection refraction angle β greatly changes, and thus there is a problem that ultrasonic waves cannot be incident on the region to be inspected. .

17 and 18 show an ultrasonic probe calculated under the condition that the flaw detection refraction angle β is 45 degrees and the ultrasonic focus is formed at 3 / 4t with respect to the inspection object thickness t when the inspection object is a plane. It is the result which showed the intensity | strength of the ultrasonic wave at the time of injecting an ultrasonic wave into a curved surface on 1 transmission delay conditions by sound field simulation.

As shown in FIG. 17, it is possible to confirm that the ultrasonic waves are not accurately incident from the curved surface although the ultrasonic waves are incident on the inside of the inspection object 2 from a part of the flat surface portion. . On the other hand, when an ultrasonic wave is incident under a transmission delay condition corresponding to a curved surface as shown in FIG.
It can be confirmed that ultrasonic waves are also incident into the inspection object 2 from the curved surface.

In this way, the flaw detection conditions inside the inspection object 2 are made constant by controlling the incident angle at each position so that the flaw detection conditions inside the inspection object 2 are equivalent according to the surface shape of the inspection object 2. An ultrasonic wave can be incident on a position where the flaw cannot be detected.

Also in the present embodiment, when the flaw detection result is reconstructed as described above, it is necessary to perform reconstruction according to the surface shape. For example, FIG. 19 shows a result of calculating a delay time condition for ultrasonic transmission in consideration of the shape of a curved surface and reconstructing the flaw detection result without considering the influence of the curved surface shape of the surface.

According to FIG. 19, the corner echo portion is a position affected by the curved surface, but the instruction of the corner echo extends in an arc shape, and the peak indication position slightly deviates from the actual corner position. It can be confirmed.

On the other hand, FIG. 20 shows the result of reconstruction in consideration of the influence of the curved surface shape. It can be confirmed that the corner echo instruction is clarified as compared with FIG. 19, and the error of the peak instruction position is also eliminated. The defect position is also equivalent to the defect position that is actually given.

As described above, according to the present embodiment, an ultrasonic wave with high detection accuracy is obtained for the surface of the inspection object 2 formed in a complicated shape by reconstructing the flaw detection result according to the surface shape of the inspection object 2. It becomes possible to provide a flaw detection apparatus and an ultrasonic flaw detection method. As a result, accurate ultrasonic flaw detection can be performed, and the reliability of the apparatus can be improved.

In addition, this embodiment is not only when flaw detection is performed under a transmission delay condition that does not consider the surface shape,
The present invention can also be applied to a case where flaw detection is performed under a transmission delay condition in consideration of the shape. Also,
In the above embodiment, the inspection object 2 has been described with respect to a non-planar shape. However, the inspection object is a flat surface, but the positional relationship between the ultrasonic probe 1 and the inspection object 2 is non-parallel or the positional relationship is parallel. However, it is also effective when it is desired to perform accurate measurement by removing the influence of the installation error of the distance from the ultrasonic probe 1 to the surface of the inspection object 2 as much as possible. That is, inspection object 2
It is possible to improve the flaw detection accuracy by reconstruction using surface information such as the surface shape and relative angle at the position where ultrasonic waves are incident on the surface.

Furthermore, although the embodiment of the present invention has been described as described above, this embodiment is presented only as an example, and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention.

For example, in the above-described embodiment, it has been described that the surface shape information is acquired from the design data or the surface shape is measured during the inspection, but may be measured in advance before the inspection.

In the above-described embodiment, the incident point Sm is specified using the center position Em of the element and the incident angle αi of the ultrasonic wave. For example, the surface inclination θ at each position of the surface coordinate S is first determined. Calculation is performed according to Snell's law from the coordinates S1 to the coordinates Sn with respect to the center position Em and a certain position Smmm in the inspection object 2, and the value that minimizes the absolute value of the calculation result is incident in the positional relationship between Em and Smmm Calculation with the point Sm is also possible.

Here, the coordinate where the calculation result is 0 is a true incident point, but depending on the number of coordinates S set, the coordinate may not be set at the true incident point. The coordinate S that minimizes the value may be adopted as the incident position.

These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic probe 2 ... Test object 3 ... Acoustic contact medium 4 ... Ultrasonic transmission / reception part 5 ... Drive element control part (delay means)
6 ... Signal recording section (storage means)
7. Analysis unit (analysis means)
8 ... Display 9 ... Design database

Claims (2)

By driving multiple ultrasonic elements, ultrasonic waves are incident on the inspection object at an incident angle calculated in advance based on the positional relationship between the ultrasonic probe and the inspection object and the conditions to be detected, and the reflected ultrasound from the inspection object is reflected. An ultrasonic probe for receiving sound waves;
An ultrasonic flaw detection apparatus comprising: analysis means for analyzing a reception signal when the ultrasonic probe receives reflected ultrasonic waves and calculating a flaw detection result;
In addition to the pre-calculated incident angle of the ultrasonic wave by the ultrasonic element, the analyzing means is incident on the basis of the surface shape information of the inspection object on which the ultrasonic wave is incident. An ultrasonic flaw detector which calculates an angle and calculates a flaw detection result using the propagation path of the ultrasonic wave according to the actually incident angle. By driving multiple ultrasonic elements of the ultrasonic probe, the ultrasonic wave is incident on the inspection object at the pre-calculated incident angle calculated in advance based on the positional relationship between the ultrasonic probe and the inspection object and the condition to be detected. An ultrasonic incident step,
After the ultrasonic wave incident step, an ultrasonic wave receiving step of receiving reflected ultrasonic waves from the inspection object;
After the ultrasonic reception step, an analysis step of calculating a flaw detection result by analyzing a reception signal when the ultrasonic probe receives reflected ultrasonic waves, and an ultrasonic flaw detection method comprising:
In the analysis step, the incident light that is actually incident based on the surface shape information of the inspection object on which the ultrasonic wave is incident, separately from the pre-calculated incident angle of the ultrasonic wave by the ultrasonic element. An ultrasonic flaw detection method characterized by calculating an angle and calculating a flaw detection result using the propagation path of the ultrasonic wave according to the actually incident angle.

Images