JP2019132748A - Ultrasonic probe - Google Patents

Abstract

To provide an ultrasonic probe with which it is possible to inspect a defect present not just in the inside area but also in the surface area of an inspection object.SOLUTION: Provided is an ultrasonic probe (1) comprising a transmission oscillator (10), a first reception oscillator (20), a second reception oscillator (30), an acoustic isolation unit (40), and a wedge (50). The wedge (50) includes: a transmission oscillator holding unit (51) for holding the transmission oscillator (10) at an angle at which a longitudinal wave transmitted from the transmission oscillator (10) enters an inspection object (T) as a traverse wave and a creeping wave is generated when the traverse wave enters the inspection object (T); a first reception oscillator holding unit (52) for holding the first reception oscillator (20) at an angle at which a reflected ultrasonic wave is receivable by the first reception oscillator (20); an acoustic insulation unit holding unit (54); and a second reception oscillator holding unit (53) for holding the second reception oscillator (30) at an angle at which a reflected creeping wave is receivable by the second reception oscillator (30).SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultrasonic probe for inspecting a defect to be inspected.

  Conventionally, a so-called two-vibrator vertical probe is known as one of means for inspecting a defect that is non-destructive and exists in an inspection target such as a steel material. For example, Patent Document 1 discloses an ultrasonic probe including a transmission transducer, a transmission acoustic delay material, a reception transducer, a reception acoustic delay material, and an acoustic separator ( A dual element vertical probe) is disclosed.

JP 2003-302388 A

  In an ultrasonic probe as described in Patent Document 1, it is possible to detect a defect existing inside an inspection target, but a defect in a surface region (surface or a region in the vicinity thereof) of the inspection target is detected. It cannot be inspected.

  An object of the present invention is to provide an ultrasonic probe capable of inspecting defects existing in a surface region in addition to an internal region to be inspected.

  In order to solve the above-mentioned problems, the present inventors have focused on the fact that creeping waves are generated when inspecting defects with a so-called two-vibrator vertical probe. The creeping wave is an ultrasonic wave that is generated when an ultrasonic wave (longitudinal wave) transmitted from the transmission vibrator is incident on the inspection object as a transverse wave, and is a longitudinal wave that propagates through the surface region of the inspection object. By using this creeping wave, it has been thought that it is possible to detect defects present in the surface area of the inspection object.

  The present invention has been made based on such a viewpoint. Specifically, the present invention absorbs ultrasonic waves, a transmission transducer that transmits longitudinal waves as ultrasonic waves, a first reception transducer that receives ultrasonic waves, a second reception transducer that receives ultrasonic waves, and the like. An acoustic isolating unit; and a wedge that holds the transmitting transducer, the first receiving transducer, the second receiving transducer, and the acoustic isolating unit, wherein the wedge is a longitudinal axis transmitted from the transmitting transducer. A transmission vibrator holding that holds the transmission vibrator at an angle that causes a wave to enter the inspection object as a transverse wave and generate a creeping wave that propagates through the surface region of the inspection object when the transverse wave enters the inspection object. And the reflected wave generated by reflection of a transverse wave propagating in the inspection object by a defect existing in the internal region of the inspection object at an angle at which the first reception transducer can receive the first reception. First received vibration holding the vibrator A holding unit, an acoustic isolation unit holding unit that holds the acoustic isolation unit between the transmission transducer holding unit and the first reception transducer holding unit, and the creeping wave is present in the surface region of the inspection object An ultrasonic wave having a second receiving transducer holding unit that holds the second receiving transducer at an angle at which the second receiving transducer can receive a reflected creeping wave generated by reflecting with a defect that Provide a probe.

  In this ultrasonic probe, a first receiving transducer that receives reflected ultrasonic waves generated by reflection of a transverse wave that has been transmitted from the transmitting transducer and entered the inspection target is reflected by a defect present in the inner region of the inspection target. And a reflection creeping wave generated by reflecting a creeping wave generated when the longitudinal wave transmitted from the transmission vibrator is incident on the inspection target by a defect existing in the surface region of the inspection target. In addition to the defects present in the internal area to be inspected, the defects present in the surface area can also be detected. The surface region means a region corresponding to a depth of several wavelengths of creeping waves from the surface to be inspected.

  Further, it is preferable that the second receiving transducer holding unit is provided between the acoustic isolation unit holding unit and the first receiving transducer holding unit.

  This prevents the second receiving transducer from receiving the longitudinal wave transmitted from the transmitting transducer, so the SN of the signal generated when the second receiving transducer receives the ultrasonic wave. The ratio increases.

  Further, the second receiving transducer holding unit holds the second receiving transducer such that an angle formed by the first receiving transducer and the second receiving transducer is 70 degrees or more and 110 degrees or less. Preferably it is.

  In this way, it is possible to suppress the second receiving transducer from receiving the reflected ultrasonic wave generated at the time of reflection at the defect existing in the internal region to be inspected. Specifically, since the reflected ultrasonic wave (transverse wave) becomes a longitudinal wave when entering the wedge again, the angle formed by the first receiving transducer and the second receiving transducer that receives the longitudinal wave is 70. By setting the angle to be not less than 110 degrees and not more than 110 degrees, the longitudinal wave is suppressed from being received by the second receiving transducer.

  The ultrasonic probe further includes a third receiving transducer that receives ultrasonic waves, and the wedge has an angle at which the third receiving transducer can receive the reflected creeping wave. A third receiving transducer holding unit that holds the transmitting transducer in a direction connecting the transmitting transducer holding unit and the first receiving transducer holding unit. It is preferable that it is provided on the opposite side to the sound isolation part holding part with respect to the holding part.

  If it does in this way, the defect which exists directly under the side by which the transmission vibrator is arrange | positioned rather than the acoustic isolation part among wedges, and the side by which the 1st receiving vibrator is arrange | positioned rather than the acoustic isolation part among wedges It is possible to discriminate from a defect that exists immediately below.

  The transmitting vibrator is preferably a broadband vibrator. Note that the broadband vibrator refers to a vibrator that generates an ultrasonic pulse of about one wave or two waves.

  In this aspect, it is possible to detect a defect existing in the surface region to be inspected by the transmitting vibrator and the first receiving vibrator. Specifically, since the ultrasonic wave transmitted from the broadband transducer has a small number of waves, the reception signal of the reflected ultrasonic wave generated by the reflection on the surface of the inspection target at the first receiving transducer, It is possible to distinguish a reflected ultrasonic wave generated by reflecting a defect existing in the surface region from a received signal at the first receiving transducer.

  As described above, according to the present invention, it is possible to provide an ultrasonic probe capable of inspecting defects existing in a surface region in addition to an internal region to be inspected.

It is a figure which shows the outline | summary of the ultrasonic probe of 1st Embodiment of this invention. It is a figure which shows the example of the received signal received with a 1st receiving vibrator when a wideband vibrator is used as a transmitting vibrator. It is a figure which shows the example of the received signal received with a 1st receiving vibrator, when a narrowband vibrator is used as a transmitting vibrator. It is a figure which shows the outline | summary of the ultrasonic probe of 2nd Embodiment of this invention. FIG. 5 is a perspective view of the ultrasonic probe shown in FIG. 4. It is a figure which shows the modification of the ultrasonic probe of 1st Embodiment. It is a figure which shows the example of the defect detection signal by a creeping wave.

(First embodiment)
An ultrasonic probe 1 according to a first embodiment of the present invention will be described with reference to FIG. In addition to the defect f1 existing in the inner region of the inspection target T (steel material in the present embodiment), the ultrasonic probe 1 is applied to the surface of the inspection target T or a region in the vicinity thereof (hereinafter referred to as “surface region”). The existing defect f2 can also be inspected. Specifically, the ultrasonic probe 1 includes a transmission transducer 10, a first reception transducer 20, a second reception transducer 30, an acoustic isolation unit 40, and a wedge 50.

  The transmission vibrator 10 transmits a longitudinal wave L as an ultrasonic wave. Specifically, it is preferable to use a broadband transducer (a transducer that generates an ultrasonic pulse of about 1 wave or 2 waves) as the transmission transducer 10.

  The first receiving transducer 20 and the second receiving transducer 30 each receive an ultrasonic wave and generate a signal corresponding to the ultrasonic wave. This signal is sent to a flaw detection apparatus (not shown) via a cable.

  The acoustic isolator 40 absorbs ultrasonic waves. In the present embodiment, the sound isolation unit 40 is made of cork, rubber, or the like.

  The wedge 50 holds the vibrators 10 and 20 and the sound isolating unit 40. Specifically, the wedge 50 includes a first acoustic delay material 50A and a second acoustic delay material 50B. In the present embodiment, the first acoustic delay member 50 </ b> A includes a transmission transducer holding unit 51 that holds the transmission transducer 10 and an acoustic isolation unit holding unit 54 that holds the acoustic isolation unit 40. The second acoustic delay member 50 </ b> B includes a first reception transducer holding unit 52 that holds the first reception transducer 20 and a second reception transducer holding unit 53 that holds the second reception transducer 30. Yes.

  The transmission vibrator holding unit 51 causes the longitudinal wave L transmitted from the transmission vibrator 10 to be incident on the inspection target T as the transverse wave S, and the surface region of the inspection target T when the transverse wave S is incident on the inspection target T. The transmitting vibrator 10 is held at an angle that generates a propagating creeping wave C. Specifically, the transmission vibrator holding unit 51 includes a straight line perpendicular to the surface of the inspection target T and a transmission direction of the longitudinal wave L transmitted from the transmission vibrator 10 (a direction perpendicular to the transmission vibrator 10). The transmission vibrator 10 is held so that the formed angle θ1 becomes an angle near the critical angle of the longitudinal wave L transmitted from the transmission vibrator 10. Here, the “angle near the critical angle” is the critical angle ± 5 degrees, and preferably the critical angle ± 3 degrees. The surface region means a region corresponding to a depth of several wavelengths of the creeping wave C from the surface of the inspection target T.

  The first reception transducer holding unit 52 is configured so that the first reception transducer 20 generates reflected ultrasonic waves generated by reflecting the transverse wave S propagating through the inspection target T by the defect f1 existing in the inner region of the inspection target T. The first receiving transducer 20 is held at a receivable angle. The reflected ultrasonic wave becomes a longitudinal wave L when entering the second acoustic delay material 50B of the wedge 50 from the inspection target T. A signal generated when the first reception transducer 20 receives the reflected ultrasonic wave (longitudinal wave L) is sent from the first reception transducer 20 to the flaw detection apparatus. That is, the defect f1 existing in the inner region of the inspection target T is detected by the transmission transducer 10 and the first reception transducer 20.

  The acoustic isolation unit holding unit 54 holds the acoustic isolation unit 40 between the transmission transducer holding unit 51 and the first reception transducer holding unit 52. The acoustic isolation unit 40 is held by the acoustic isolation unit holding unit 54, so that the ultrasonic wave transmitted from the transmission transducer 10 into the first acoustic delay member 50A does not pass through the inspection target T, and the first reception transducer. 20 is suppressed.

  The second receiving vibrator holding unit 53 is an angle at which the second receiving vibrator 30 can receive the reflected creeping wave generated by the reflection of the creeping wave C by the defect f2 existing in the surface region of the inspection target T. The second receiving transducer 30 is held. A signal generated when the second receiving transducer 30 receives the reflected creeping wave is sent from the second receiving transducer 30 to the flaw detection apparatus. That is, the defect f2 existing in the surface region of the inspection target T is detected by the transmission transducer 10 and the second reception transducer 30. In the present embodiment, the second reception transducer holding unit 53 is provided between the acoustic isolation unit holding unit 54 and the first reception transducer holding unit 52. The second receiving vibrator holding unit 53 holds the second receiving vibrator 30 so that the angle θ2 formed by the first receiving vibrator 20 and the second receiving vibrator 30 is 70 degrees or more and 110 degrees or less. Is preferred. In the present embodiment, the second receiving vibrator holding unit 53 holds the second receiving vibrator 30 so that the angle θ2 is 90 degrees.

  As described above, in the ultrasonic probe 1 of the present embodiment, the transverse wave S transmitted from the transmission transducer 10 and entering the inspection target T is reflected by the defect f1 existing in the inner region of the inspection target T. The first receiving transducer 20 that receives the reflected ultrasonic wave generated by this, and the creeping wave C generated when the longitudinal wave transmitted from the transmitting transducer 10 enters the inspection target T is the surface region of the inspection target T. In addition to the defect f1 existing in the internal region of the inspection target T, the second receiving vibrator 30 that receives the reflected creeping wave generated by reflecting with the defect f2 existing in the surface is provided. A defect f2 existing in the region can also be detected.

  In addition, since the second receiving transducer holding unit 53 is provided between the acoustic isolation unit holding unit 54 and the first receiving transducer holding unit 52, the longitudinal wave L transmitted from the transmitting transducer 10 is transmitted to the first receiving transducer holding unit 53. 2 The reception by the receiving transducer 30 is avoided. Therefore, the SN ratio of the signal generated when the second receiving transducer 30 receives the ultrasonic wave increases.

  Furthermore, since the second receiving transducer holding unit 53 holds the second receiving transducer 30 so that the angle θ2 formed by the first receiving transducer 20 and the second receiving transducer 30 is 90 degrees, The second receiving transducer 30 is prevented from receiving reflected ultrasonic waves generated at the time of reflection at the defect f1 existing in the inner region of the inspection target T. Specifically, the reflected ultrasonic wave (transverse wave S) becomes a longitudinal wave L when entering the second acoustic delay material 50B of the wedge 50 again, and therefore the first receiving vibrator 20 that receives the longitudinal wave L. And the second receiving transducer 30 are set to 90 degrees, the reception of the longitudinal wave L by the second receiving transducer 30 is suppressed.

  Furthermore, by using the wideband vibrator as the transmission vibrator 10, one of the parts of the surface region of the inspection target T that overlaps the wedge 50 (below the wedge) by the transmission vibrator 10 and the first reception vibrator 20 is used. It is possible to detect the defect f2 ′ present in the portion (directly below the acoustic isolation portion 40). Specifically, since the ultrasonic wave transmitted from the broadband transducer has a small number of waves, the first reception of the reflected ultrasonic wave generated by reflecting on the surface of the inspection target T as shown in FIG. It is possible to distinguish between the reception signal A1 at the transducer 20 and the reception signal A2 at the first reception transducer 20 of the reflected ultrasonic wave generated by being reflected by the defect f2 ′. On the other hand, when a narrow-band transducer is used as the transmitting transducer 10, as shown in FIG. 3, the reflected ultrasonic wave generated by reflecting on the surface of the inspection target T at the first receiving transducer 20 It is difficult to discriminate between the reception signal a1 and the reception signal a2 of the reflected ultrasonic wave generated by reflection at the defect f2 ′ at the first reception transducer 20. In any case, the reception signals A3 and a3 of the reflected ultrasonic waves generated by the reflection by the defect f1 at the first reception transducer 20 can be clearly distinguished from other reception signals.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, only parts different from the first embodiment will be described, and the description of the same structure, operation, and effect as in the first embodiment will be omitted.

  The ultrasonic probe 1 of the present embodiment further includes a third reception transducer 35, and the wedge 50 further includes a third reception transducer holding unit 55 that holds the third reception transducer 35.

  The third receiving transducer 35 receives an ultrasonic wave and generates a signal corresponding to the ultrasonic wave. This signal is sent to the flaw detector via a cable.

  The third reception transducer holding unit 55 holds the third reception transducer 35 at an angle at which the third reception transducer 35 can receive the reflected creeping wave. The third receiving transducer holding unit 55 is an acoustic isolating unit with respect to the direction connecting the transmitting transducer holding unit 51 and the first receiving transducer holding unit 52 (left-right direction in FIG. 4) with the transmitting transducer holding unit 51 as a reference. It is provided on the side opposite to the holding portion 54.

  In the present embodiment, it is possible to distinguish between a defect present immediately below the first acoustic delay material 50A and a defect present directly below the second acoustic delay material 50B.

  Further, as shown in FIG. 5, a portion of the surface of the first acoustic delay member 50 </ b> A excluding the lower surface of the first acoustic delay member 50 </ b> A (a portion indicated by hatching in FIG. 5) An absorber 60 that absorbs sound waves is provided. For this reason, the longitudinal wave L transmitted from the transmission transducer 10 is suppressed from being received by the third reception transducer 35. In addition, illustration of the absorption part 60 is abbreviate | omitted in FIG.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first embodiment, an example in which the second reception transducer holding part 53 that holds the second reception transducer 30 is provided in the second acoustic delay member 50B is shown, but as shown in FIG. The second receiving vibrator holding unit 53 may be provided on the first acoustic delay material 50A. In this case, similarly to the second embodiment, it is preferable that the absorbing portion 60 is provided in the first acoustic delay material 50A.

  Next, verification by simulation was implemented about the said embodiment. In this embodiment, the ultrasonic probe 1 in which the frequency of the transmission vibrator 10 is set to 5 MHz, the angle θ1 is set to 27 degrees, and the angle θ2 is set to 90 degrees is used. Further, as the inspection target T, a steel material having a defect f2 having a size of 1 mm × 1 mm on the surface was used.

  FIG. 7 shows a signal obtained from the second receiving transducer 30 when the inspection target T is inspected by the ultrasonic probe 1. As shown in FIG. 7, the signal B generated when the second receiving transducer 30 receives the reflected creeping wave was clearly confirmed. Although not shown in the figure, the signal generated when the first receiving transducer 20 receives the reflected ultrasonic wave was also clearly confirmed. Thus, in this example, it was confirmed that in addition to the defect f1 existing in the internal region of the inspection target T, the defect f2 existing in the surface region can also be detected.

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 10 Transmitting transducer 20 First receiving transducer 30 Second receiving transducer 35 Third receiving transducer 40 Acoustic isolation unit 50 Wedge 50A First acoustic delay material 50B Second acoustic delay material 51 Transmitting transducer holding unit 52 First receiving vibrator holding section 53 Second receiving vibrator holding section 54 Absorbing section holding section 55 Third receiving vibrator holding section 60 Absorbing section C Creeping wave L Longitudinal wave S Transverse wave

Claims (5)

A transmission transducer that transmits longitudinal waves as ultrasonic waves;
A first receiving transducer for receiving ultrasonic waves;
A second receiving transducer for receiving ultrasonic waves;
An acoustic isolator that absorbs ultrasound,
A wedge for holding the transmission vibrator, the first reception vibrator, the second reception vibrator, and the acoustic isolation unit;
The wedge is
The longitudinal wave transmitted from the transmission vibrator is incident on the inspection object as a transverse wave, and the transmission is generated at an angle that generates a creeping wave propagating through the surface region of the inspection object when the transverse wave is incident on the inspection object. A transmission vibrator holding section for holding a vibrator;
The first receiving transducer is moved at an angle at which the first receiving transducer can receive reflected ultrasonic waves generated by reflection of a transverse wave propagating in the inspection subject by a defect existing in an inner region of the inspection subject. A first receiving vibrator holding unit for holding;
An acoustic isolation unit holding unit that holds the acoustic isolation unit between the transmission transducer holding unit and the first reception transducer holding unit;
The second receiving transducer is held at an angle at which the second receiving transducer can receive the reflected creeping wave generated by reflecting the creeping wave with a defect present in the surface region of the inspection object. And an ultrasonic probe. The ultrasonic probe according to claim 1,
The second receiving transducer holding unit is an ultrasonic probe provided between the acoustic isolation unit holding unit and the first receiving transducer holding unit. The ultrasonic probe according to claim 2,
The second reception transducer holding unit holds the second reception transducer such that an angle formed by the first reception transducer and the second reception transducer is 70 degrees or more and 110 degrees or less. Ultrasonic probe. The ultrasonic probe according to claim 2 or 3,
A third receiving transducer for receiving ultrasonic waves;
The wedge has a third receiving vibrator holding unit that holds the third receiving vibrator at an angle at which the third receiving vibrator can receive the reflected creeping wave;
The third receiving transducer holding unit is opposite to the acoustic isolation unit holding unit with respect to the direction connecting the transmitting transducer holding unit and the first receiving transducer holding unit with respect to the transmitting transducer holding unit. An ultrasonic probe is provided. The ultrasonic probe according to any one of claims 1 to 4,
The transmitting transducer is an ultrasonic probe, which is a broadband transducer.

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