JP2018004522A - Ultrasonic flaw detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve detection sensitivity.SOLUTION: An ultrasonic flaw detection device comprises: an array probe 110 that is configured to include a transmission unit 120 composed of a plurality of oscillators transmitting an ultrasonic to an interior of an inspection object 10, and a reception unit 130 composed of the plurality of oscillators receiving the ultrasonic reflected inside the inspection object 10; and a delay material 150 that is disposed between the inspection object 10 and the array probe 110, and has a first layer 170, and a second layer 180 disposed on an array probe 110 side relative to the first layer 170, and composed of a substance having an ultrasonic propagation velocity different from that of the first layer 170.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an ultrasonic flaw detection apparatus that flaws an inspection object using ultrasonic waves transmitted from an array probe.

  2. Description of the Related Art Conventionally, an ultrasonic flaw detector is used when inspecting defects such as scratches, cracks, and poor bonding of inspection objects. The ultrasonic flaw detection apparatus includes a transmission unit that transmits ultrasonic waves inside the inspection target and a reception unit that receives ultrasonic waves reflected in the inspection target, and the ultrasonic waves received by the reception unit Is detected to detect the presence / absence of a defect, the position and size of the defect, and the like.

  As the ultrasonic flaw detection apparatus, for example, an array probe having a plurality of transducers functioning as a transmission unit and a plurality of transducers functioning as a reception unit is provided, and each transducer constituting the transmission unit transmits ultrasonic signals. Controls the transmission time (delay time) of the sound wave to focus each ultrasonic wave, and selectively receives the reflected wave of the focused ultrasonic wave by controlling the reception time of each transducer constituting the receiver. The technique to do is disclosed (for example, patent document 1). In an ultrasonic flaw detector having such an array probe, the shape and size of a defect can be detected by moving (scanning) the focal position of the ultrasonic wave.

JP 2012-117875 A

  Since the array probe as described in Patent Document 1 electronically controls the focusing of the ultrasonic wave, the ultrasonic focusing density is set to some extent in the vicinity of the array probe on the inspection object. However, there is a limit to the improvement of defect detection sensitivity. For this reason, development of the technique which improves the detection sensitivity of a defect more is calculated | required.

  In view of such a problem, an object of the present invention is to provide an ultrasonic flaw detector capable of improving detection sensitivity.

  In order to solve the above-described problem, an ultrasonic flaw detection apparatus according to the present invention includes a transmission unit including a plurality of transducers that transmit ultrasonic waves into an inspection object, and an ultrasonic wave reflected in the inspection object. An array probe configured to include a receiving unit composed of a plurality of transducers that receive sound waves, a first layer disposed between the inspection object and the array probe, A delay material that is disposed closer to the array probe than the first layer and has a first layer and a second layer made of a material having a different propagation speed of ultrasonic waves.

  The ultrasonic transmission surface in the transmission unit and the ultrasonic reception surface in the reception unit may be arranged in the same plane.

  The second layer is stacked on the first layer and has a probe contact surface that contacts the array probe, and an interface between the first layer and the second layer is the probe. In the cross section orthogonal to the probe contact surface, the distance from the probe contact surface gradually increases toward the center, and the first layer is made of a material having a higher ultrasonic wave propagation speed than the second layer. It is good.

  The second layer is stacked on the first layer and has a probe contact surface that contacts the array probe, and an interface between the first layer and the second layer is the probe. In the cross section orthogonal to the probe contact surface, the distance from the probe contact surface gradually decreases toward the center, and the first layer is made of a material having a lower ultrasonic wave propagation speed than the second layer. It is good.

  The first layer may be made of a material having a higher scratch hardness than the second layer.

  The retarder may be composed of one or a plurality selected from the group of resin, metal, and liquid.

  According to the present invention, detection sensitivity can be improved.

It is a figure explaining an ultrasonic flaw detector. It is a figure explaining the focusing of the ultrasonic wave by an array probe. It is a 1st figure explaining a delay material. It is a 2nd figure explaining a delay material. It is a figure explaining a part of parameter calculation procedure.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Ultrasonic flaw detector 100)
FIG. 1 is a diagram for explaining an ultrasonic flaw detector 100. In the following drawings including FIG. 1 of the present embodiment, an X axis (horizontal direction), a Y axis (horizontal direction), and a Z axis (vertical direction) that intersect perpendicularly are defined as illustrated.

  As shown in FIG. 1A, the ultrasonic flaw detector 100 includes an array probe 110 and a delay material 150. As shown in FIGS. 1A and 1B, the array probe 110 includes a transmission unit 120 that transmits ultrasonic waves in response to a control command from a control unit (not shown), and a control command from the control unit. And a receiving unit 130 that receives ultrasonic waves. Then, the ultrasonic wave transmitted from the transmission unit 120 of the array probe 110 (indicated by a dashed arrow in FIG. 1B) passes through the delay material 150 and enters the inspection object 10 to be inspected. The ultrasonic wave reflected in the object 10 passes through the delay material 150 and reaches the receiving unit 130.

  In addition, although mentioned later in detail, the sound shielding material 152 comprised by the cork etc. which hardly transmits an ultrasonic wave is provided in the location corresponding to the boundary of the transmission part 120 and the receiving part 130 in the delay material 150. . With the configuration including the sound blocking material 152, it is possible to avoid a situation in which the ultrasonic wave transmitted from the transmission unit 120 reaches the reception unit 130 directly, and noise can be reduced.

  As shown in FIG. 1C, the array probe 110 according to the present embodiment includes a plurality of (in this case, 16) transducers 114 in a matrix shape (4 ×× 4) in a rectangular parallelepiped housing 112. 4), a so-called matrix type array probe. In the array probe 110 of the present embodiment, a plurality of transducers 114 are arranged in the same plane within the housing 112.

  In the array probe 110 of the present embodiment, among the plurality of transducers 114, eight transducers 114 (2 × 4, arranged in the right side in FIG. 1C) in FIG. 1C. , Indicated by white fill) function as the transmission unit 120, and eight transducers 114 (2 × 4, indicated by hatching in FIG. 2) arranged on the left side in FIG. It functions as 130. Therefore, in the array probe 110, the transmission unit 120 and the reception unit 130 are adjacent to each other, and the ultrasonic transmission surface 122 of the transmission unit 120 and the ultrasonic reception surface 132 of the reception unit 130 are in the same plane. Will be arranged.

  FIG. 2 is a diagram for explaining focusing of ultrasonic waves by the array probe 110. As shown in FIG. 2A, in the array probe 110, the transmission time of the ultrasonic waves transmitted by the transducers 114 constituting the transmission unit 120 is controlled to focus the ultrasonic waves (FIG. 2 ( a) Indicated by cross-hatching). Then, by controlling the reception time of each transducer 114 constituting the receiving unit 130, the reflected reflected wave of the ultrasonic wave is selectively received. Thus, the presence or absence of a defect is detected by analyzing the received reflected wave. In the array probe 110, the shape and size of the defect can be detected by moving the focus position of the ultrasonic wave.

  However, in the array probe 110, since focusing of ultrasonic waves is electronically controlled, as shown in FIG. 2 (b), when a conventional delay member 50 composed of one substance is used, In the vicinity 12 of the delay material 50 in the inspection object 10, the focused density of the ultrasonic wave can be increased only to a certain extent. For this reason, noise is increased, and there is a limit to the improvement of defect detection sensitivity.

  Therefore, as shown in FIG. 2C, a configuration using two array probes 110 has been developed. More specifically, one array probe 110 functions as the transmission unit 120 and the other array probe 110 functions as the reception unit 130, and the angle formed by the transmission surface 122 and the reception surface 132 is 180. Install so that it is less than °°. In this configuration, since the ultrasonic waves can be refracted by the inclination angle between the transmission surface 122 and the reception surface 132, one array probe 110 is used as shown in FIGS. 2 (c) and 2 (d). Compared to the case, even when the conventional delay member 60 is used, the focusing density of the ultrasonic wave can be increased in the vicinity 12 of the delay member 50 in the inspection object 10.

  However, when two array probes 110 are used, it is necessary to increase the delay material 60 as compared with the case where one array probe 110 is used, and the ground contact area of the delay material 60 in the inspection target 10 is large. growing. If it does so, there exists a problem that installation of the delay material 60 becomes difficult when the test object 10 is small or the surface of the test object 10 is uneven. In addition, since the ground contact area increases, there is a problem that noise increases depending on the surface shape of the inspection object 10.

  Therefore, the ultrasonic flaw detection apparatus 100 according to the present embodiment devises the delay member 150 so that the ultrasonic focusing density in the vicinity of the delay member 150 in the inspection target 10 can be achieved even with one array probe 110. The detection sensitivity of defects can be improved. Hereinafter, the retarder 150 will be described in detail.

  3 and 4 are diagrams for explaining the delay member 150, FIG. 3 (a) shows a perspective view of the delay member 150, and FIG. 3 (b) shows a side view of the delay member 150. FIG. 4 shows a sectional view taken along line IV in FIG. 3B (a sectional view perpendicular to the probe contact surface 164).

  As shown in FIGS. 3A and 3B, the delay member 150 includes an object contact surface 160 that contacts the inspection object 10, a parallel surface 162 that is parallel to the object contact surface 160, and an object contact surface. And a probe contact surface 164 having an acute angle with 160. As shown in FIG. 4, the array probe 110 is installed on the delay member 150 so that the transmission surface 122 and the reception surface 132 are in contact with the probe contact surface 164.

  The retarder 150 includes a first layer 170 having an object contact surface 160 and a second layer 180 laminated on the first layer 170 and having a probe contact surface 164. Note that the sound blocking material 152 is provided at the center of the delay material 150 so that the first layer 170 and the second layer 180 are divided into two.

  In the present embodiment, the first layer 170 is made of a material having a higher scratch hardness (scratch hardness) than the second layer 180. Since the object contact surface 160 is provided on the first layer 170, the object contacts the inspection object 10. Therefore, it is possible to suppress damage to the retarder 150 (target object contact surface 160) by configuring the first layer 170 with a material having a relatively high scratch hardness.

  Further, the first layer 170 and the second layer 180 are made of materials having different ultrasonic propagation speeds. In the present embodiment, the first layer 170 is more sensitive to ultrasonic propagation speed than the second layer 180. Is composed of a large substance. For example, the first layer 170 is made of acrylic, and the second layer 180 is made of polystyrene.

  Therefore, the ultrasonic wave transmitted from the transmission unit 120 (transmission surface 122) passes through the second layer 180 and the first layer 170 in this order, and then enters the inspection object 10. By configuring the first layer 170 and the second layer 180 with materials having different propagation speeds of ultrasonic waves, the ultrasonic waves are refracted at the interface 190 between the first layer 170 and the second layer 180 (Snell's). law).

  In the ultrasonic flaw detector 100 of the present embodiment, the array probe 110 is installed on the sound blocking material 152 so that the boundary between the transmission surface 122 and the reception surface 132 is disposed. A cross section in which the interface 190 between the first layer 170 and the second layer 180 is orthogonal to the probe contact surface 164 (specifically, orthogonal to the probe contact surface 164 and the transmission surface 122 and the reception surface). 132, the distance from the probe contact surface 164 gradually increases toward the center (sound blocking material 152) from the one end 190a and the other end 190b at the boundary (cross section orthogonal to the sound blocking material 152) (object). The first layer 170 and the second layer 180 are formed so that the distance from the contact surface 160 gradually decreases. That is, the first layer 170 and the second layer 180 are formed so that the interface 190 is V-shaped in a cross section orthogonal to the probe contact surface 164.

  By configuring the interface 190 as described above, it is possible to refract the ultrasonic wave transmitted from the transmission unit 120 toward the acoustic blocking material 152 side (reception unit 130 side) at the interface 190. In addition, it is possible to refract the ultrasonic wave reflected in the inspection object 10 toward the acoustic blocking material 152 side (transmission unit 120 side) at the interface 190.

  Thereby, even in the vicinity of the delay member 150 (array probe 110) in the inspection object 10, the focusing density of the ultrasonic wave can be increased, and the defect detection sensitivity can be improved.

(Determination of the angle of the interface 190 and calculation of parameters)
In general, the software used by the control unit that drives the ultrasonic flaw detector uses the two array probes 110 and the conventional delay member 60 to set the ultrasonic transmission time (delay time). It is configured to be able to selectively receive reflected waves of the focused ultrasonic waves by controlling and focusing each ultrasonic wave or by controlling the reception time of each transducer 114 constituting the receiving unit 130. ing.

  Therefore, the angle of the interface 190 is set so that the ultrasonic flaw detector 100 of this embodiment can be driven using the software used when the two array probes 110 and the conventional delay member 60 are used as they are. Determine and calculate the parameters.

  First, a roof angle (an angle formed by the transmission surface 122 and the reception surface 132) necessary for focusing the ultrasonic wave at a desired position, and an angle (a refraction angle) at which the ultrasonic wave can be refracted by the conventional delay material 60. ) Is determined using simulation. It is assumed that the delay material 60 is made of the same material as the second layer 180.

  Next, the interface 190 is determined so that the angle sα of the ultrasonic wave incident on the inspection object 10 from the first layer 170 becomes the roof angle.

FIG. 5 is a diagram for explaining a part of the parameter calculation procedure. As shown in FIG. 5A, the angle formed by the propagation direction of the ultrasonic wave transmitted from the transmission unit 120 and the perpendicular of the interface 190 is α, the propagation direction of the ultrasonic wave in the first layer 170, and the interface 190 If the angle formed with the perpendicular is β, the angle sα can be derived from the following equations (1) and (2).
v2 / sin α = v1 / sin β (1)
sα = β−α Equation (2)
Here, v1 is an ultrasonic wave propagation speed in the first layer 170, and v2 is an ultrasonic wave propagation speed in the second layer 180.

  The retarder 150 is created by determining the angle of the interface 190 to be the angle sα thus derived.

Subsequently, the parameter L4 is derived using the following equation (3), and the parameter L6 is derived using the following equation (4).
L4 = ((k / 4−t / 2) × tan (α) + h) ÷ cos (sα) + (j− (k / 4−t / 2) × tan (α)) × v1 / v2 (formula ( 3)
L6 = k / 4 + (j− (k / 4−t / 2) × tan (α)) × v1 / v2 × sin (sα) −k / 4 × cos (sα) (4)
Here, as shown in FIG. 5B, k is the width of the transmitter 120, and j is the distance from the probe contact surface 164 to the position closest to the object contact surface 160 in the interface 190. , H is the distance from the position closest to the object contact surface 160 in the interface 190 to the object contact surface 160, and t is the width (thickness) of the sound blocking material 152.

  The parameter L4 derived in this way is substituted into the propagation distance of the ultrasonic wave in the delay material 60 in the software, and the parameter L6 is substituted into the half value (× 0.5) of the separation distance between the transmission unit 120 and the reception unit 130. Thus, ultrasonic flaw detection can be performed using existing software without developing software dedicated to the ultrasonic flaw detection apparatus 100.

  As described above, according to the ultrasonic flaw detector 100 according to the present embodiment, not only the ultrasonic wave is refracted electronically but also the delay material 150 is configured with a simple configuration in which the delay material 150 is devised. The ultrasonic wave can be refracted by the difference in ultrasonic wave propagation speed (sound speed) between the first layer 170 and the second layer 180. As a result, even with the array probe 110, it is possible to increase the focusing density of the ultrasonic wave in the vicinity of the delay member 150 in the inspection target 10, and to reduce noise.

  For example, when the retarder 150 is used and when the retarder 50 made of only polystyrene is compared, it has been experimentally confirmed that the S / N ratio is about 8 times higher. That is, it has been found that the presence or absence of a defect can be detected even if the detection sensitivity is lowered by about 8 times.

  Further, as described above, by using one array probe 110, it is possible to reduce the delay material 150 as compared with the case where two array probes 110 are used. It is possible to reduce the ground contact area (object contact surface 160) of the material 150. Therefore, even if the inspection object 10 is small or the surface of the inspection object 10 is uneven, the object contact surface 160 can be easily installed. In addition, since the object contact surface 160 is reduced, it is possible to reduce the influence of noise due to the surface shape of the inspection object 10.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above-described embodiment, the ultrasonic flaw detector 100 has been described by taking as an example a configuration in which the array probe 110 and the delay member 150 are provided. However, the two array probes 110 and the delay material 150 may be combined. In this case, the focusing density can be further increased in the vicinity of the retarder 150 in the inspection object 10 (that is, in the vicinity of the surface of the inspection object 10).

  Moreover, in the said embodiment, the 1st layer 170 mentioned and demonstrated as an example the delay material 150 comprised with the material whose propagation speed of an ultrasonic wave is larger than the 2nd layer 180. FIG. However, it is also possible to provide the delay material 150 in which the first layer 170 is made of a material having a lower ultrasonic wave propagation speed than the second layer 180. In this case, the interface 190 between the first layer 170 and the second layer 180 may have an inverted V-shaped cross section perpendicular to the probe contact surface 164. More specifically, in this case, the distance between the interface 190 and the probe contact surface 164 gradually decreases from the one end portion 190a and the other end portion 190b toward the center (sound shielding material 152) (with the object contact surface 160). The first layer 170 and the second layer 180 are preferably formed so that the distance increases gradually.

  Moreover, in the said embodiment, the case where the interface 190 was comprised by the plane (specifically two planes) was mentioned as an example, and was demonstrated. However, the interface 190 may be a hemispherical surface.

  Moreover, in the said embodiment, the angle | corner which the interface 190 and the sound blocker 152 which are distribute | arranged to the transmission part 120 side make, and the angle which the interface 190 and the sound blocker 152 which are distribute | arranged to the receiving part side make are substantial. The case where it is equal to is described as an example. However, the angle formed by the interface 190 and the sound blocking material 152 disposed on the transmitting unit 120 side may be different from the angle formed by the interface 190 and the sound blocking material 152 disposed on the receiving unit 130 side.

  Moreover, in the said embodiment, the case where the retarder 150 was comprised by the 1st layer 170 and the 2nd layer 180 was mentioned as an example, and was demonstrated. However, the retarder 150 may be composed of three or more layers. For example, the first layer has an object contact surface 160, the second layer is laminated on the first layer, the third layer is laminated on the second layer, and the retardation material has the probe contact surface 164. May be. In this configuration, for example, the interface between the first layer and the second layer and the interface between the second layer and the third layer are V-shaped, and the phases of both interfaces are shifted by 90 °. May be.

  Moreover, in the said embodiment, the case where the 1st layer 170 was comprised with acryl and the 2nd layer 180 was comprised with polystyrene was mentioned as an example, and was demonstrated. However, the first layer 170 only needs to be made of a material having an ultrasonic wave propagation speed lower than that of the inspection object 10. Therefore, the first layer 170 and the second layer 180 are composed of one or more selected from the group of metals (for example, gold, silver), resins (for example, polyimide), and liquids (for example, water, oil, glycerin). It only has to be done.

  INDUSTRIAL APPLICABILITY The present invention can be used for an ultrasonic flaw detection apparatus that flaws an inspection target using ultrasonic waves transmitted from an array probe.

DESCRIPTION OF SYMBOLS 10 Inspection object 100 Ultrasonic flaw detector 110 Array probe 120 Transmission part 122 Transmission surface 130 Reception part 132 Reception surface 150 Delay material 160 Object contact surface 164 Probe contact surface 170 First layer 180 Second layer 190 Interface

Claims (6)

A transmission unit configured by a plurality of transducers that transmit ultrasonic waves inside the inspection target; and a reception unit configured by a plurality of transducers that receive ultrasonic waves reflected in the inspection target. An array probe comprising:
Disposed between the inspection object and the array probe, disposed on the first layer, and closer to the array probe than the first layer, and having a different ultrasonic wave propagation speed from the first layer A retarder having a second layer comprising:
An ultrasonic flaw detector comprising:   The ultrasonic flaw detection apparatus according to claim 1, wherein the ultrasonic transmission surface of the transmission unit and the ultrasonic reception surface of the reception unit are arranged in the same plane. The second layer has a probe contact surface that is stacked on the first layer and contacts the array probe;
In the cross section orthogonal to the probe contact surface, the interface between the first layer and the second layer gradually increases in distance from the probe contact surface toward the center,
3. The ultrasonic flaw detector according to claim 1, wherein the first layer is made of a material having a higher ultrasonic propagation velocity than the second layer. The second layer has a probe contact surface that is stacked on the first layer and contacts the array probe;
The interface between the first layer and the second layer is gradually reduced in distance from the probe contact surface toward the center in a cross section orthogonal to the probe contact surface.
3. The ultrasonic flaw detector according to claim 1, wherein the first layer is made of a material having an ultrasonic propagation velocity smaller than that of the second layer.   The ultrasonic flaw detector according to any one of claims 1 to 4, wherein the first layer is made of a material having a scratch hardness higher than that of the second layer.   The ultrasonic flaw detector according to any one of claims 1 to 5, wherein the delay material is composed of one or a plurality selected from a group of resin, metal, and liquid.

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