JP2605396B2 - Ultrasonic probe - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe for performing a vertical flaw detection of a round bar and a pipe by a water immersion method using, for example, a pulse reflection method.

[Conventional technology]

FIG. 6 is a diagram of an ultrasonic flaw detector using a conventional ultrasonic probe disclosed in, for example, an ultrasonic flaw detection method (published by Nikkan Kogyo Shimbun, 1974). FIG. 6 (a) is a view of the round bar or the steel tube viewed from the axial direction, and FIG. 6 (b) is a view of the round bar or the steel tube viewed from the circumferential direction. In the figure (11)
Is an ultrasonic probe, (12) is an acoustic lens inside the ultrasonic probe (11), (2) is water as an acoustic coupling material, (3) is a round bar steel or steel pipe material, and (4) is Defects in the round bar or steel pipe (3), (5) is the ultrasonic beam, (6) is the effective width of the ultrasonic beam (5), S is the surface reflected wave of the round bar or steel pipe (3), F Is a defect reflected wave inside the round steel bar or the steel pipe (3), and B is a bottom reflected wave of the round steel bar or the steel pipe (3).

An ultrasonic flaw detector using a conventional ultrasonic probe is configured as described above, and the ultrasonic waves generated inside the ultrasonic probe (11) are converged by an acoustic lens (12) and are condensed by an acoustic coupling material. The water passes through a certain water (2) and propagates inside the round bar or the steel pipe (3).

FIG. 7 shows a flaw detection pattern by an ultrasonic flaw detector using a conventional ultrasonic probe (11). In the figure, (10) is a flaw detection gate for flaw detection of round bar steel or steel pipe (3), and T1 is the first flaw detection gate.
The second transmission pulse, T2 is the second transmission pulse, and Tn is the nth transmission pulse.
The first transmission pulse, t is the repetition time of the transmission pulse, S1 is the first surface reflected wave of round bar steel or steel pipe (3) with respect to the transmission pulse T1, and S2, S3, S4, S5,. 2nd, 3rd, 4th, 5th,..., Nth surface reflected wave, B1-S1 is the first bottom surface reflection of round bar steel or steel pipe (3) to surface reflected wave S1 Wave, B2−S1,
... Bn-S1 is the second, n-th bottom reflected wave of the round bar steel or steel pipe (3) with respect to the surface reflected wave S1, B1-S2, B2
-S2, ... Bn-S2, B1-S3, ... Bn-S3, B1-S4, ... Bn-S4, Bn
-S5,... Bn-Sn are the round bar steel for the nth surface reflected wave Sn or the nth bottom surface reflected wave of the steel pipe material (3), F is the round bar steel for the first surface reflected wave S1 or The defect reflected wave inside the steel pipe material (3), F ', is a defect reflected wave inside the round bar steel or the steel pipe material (3) with respect to the second surface reflected wave S2. As shown in the figure, multiple echoes of the surface reflected wave of the round bar steel or the steel pipe (3) in the first transmission pulse T1
S1, S2,... Sn, and defect reflected waves F, F ′ inside round bar steel or steel pipe (3) and their respective surface reflected waves S1, S2,.
Many reflected waves such as multiple echoes B1, S1, B2-S1,... Bn-Sn of the bottom reflected wave of the round bar steel or the steel pipe material (3) with respect to n appear. The multiple echoes S1,... Bn, B1−S1,.
n−Sn is the repetition time t for each transmission pulse T1, T2,.
Appear at the same interval.

The ultrasonic flaw detector using the conventional ultrasonic probe (11) is configured as described above, and repeatedly transmits a transmission pulse T when it is automated, and uses a round bar or a steel pipe (3) or an ultrasonic probe. By operating the child (11), ultrasonic flaw detection is performed over the entire surface of the round bar steel or the steel pipe (3).
Further, the repetition time t of the transmission pulse T is determined according to the relative moving speed of the ultrasonic probe (11) and the round bar or the steel pipe (3). That is, in order to increase the flaw detection processing capability of the round bar steel or the steel pipe material (3), the repetition time t of the transmission pulse T must be shortened, so that the surface reflected wave S1 generated by the first transmission pulse T1 is generated. Before the second and subsequent transmission pulses T2 to Tn appear, the surface reflected wave Sn and the bottom surface reflected wave BnSn appear before to Sn and the bottom reflected waves B1-S1 to Bn-Sn do not completely disappear. Therefore, the surface reflected wave Sn and the bottom surface reflected wave Bn-Sn are erroneously detected as the defective reflected waves F.

[Problems to be solved by the invention]

As described above, in the ultrasonic flaw detector using the conventional ultrasonic probe (11) to perform vertical flaw detection of a round bar steel or a steel pipe material (3) by a water immersion method, the surface of the round bar steel or the steel pipe material (3) The reflected wave S at the probe is about 95% reflected, and about 60% reflected at the surface of the ultrasonic probe (11), so that there is a gap between the ultrasonic probe (11) and the round bar or steel pipe (3). Only about 5 to 6 dB is attenuated for each round trip. For this reason, when the amount of decrease in the reverberation echoes Sn and Bn-Sn with respect to the first surface reflected wave S1 is calculated from the defect detection capability normally required (for example, S / N ≧ 20 dB for a φ1 side hole defect), it is about -60 dB or less. There is a need to. That is, the distance between the ultrasonic probe (11) and the round bar or the steel pipe (3) is set to 10
If the second transmission pulse T2 is generated before the time to reciprocate up to 12 times elapses, Sn and Bn
A problem appears as a -Sn pseudo defect echo F. In particular, this problem is a fatal defect in an automatic flaw detection apparatus having a high flaw detection processing speed.

The present invention has been made to solve such a problem, and has as its object to prevent reverberation echo and shorten the repetition time of a transmission pulse.

[Means for solving the problem]

According to the ultrasonic probe of the present invention, the ultrasonic transducer for transmitting and receiving the ultrasonic wave has a curvature in the circumferential direction of the round bar steel or the steel pipe material, and the ultrasonic transducer and the water as the acoustic coupling material are connected to each other. An attachment having an attachment whose outer surface is not parallel to the axial outer surface of the round bar or the steel tube material.

An ultrasonic probe according to another aspect of the present invention has an attachment outer surface between an ultrasonic transducer for transmitting and receiving ultrasonic waves and water as an acoustic coupling material, which is made of round bar steel or steel pipe material. It has an attachment that is not parallel to the outer surface in the axial direction but has a curvature in the circumferential direction.

[Action]

In the present invention, the ultrasonic transducer for transmitting and receiving the ultrasonic wave inside the ultrasonic probe has a curvature in the circumferential direction of the round bar steel or the steel pipe material, and the ultrasonic transducer and the water which is an acoustic coupling material. By using an attachment whose outer surface is not parallel to the axial outer surface of the round bar or the steel pipe, the attenuation of the ultrasonic wave passing through the attachment is used to shorten the repetition time of the transmission pulse. It is possible to do. In another aspect of the present invention, the outer surface of the attachment between the ultrasonic transducer for transmitting and receiving the ultrasonic wave inside the ultrasonic ultrasonic probe and the water as the acoustic coupling material has a round bar steel or steel pipe material. By providing an attachment having a curvature in the circumferential direction, not parallel to the outer surface in the axial direction, it is possible to shorten the repetition time of a transmission pulse by using the attenuation of the ultrasonic wave passing through the attachment. It is.

〔Example〕

FIG. 1 is a view showing one embodiment of an ultrasonic flaw detector using an ultrasonic probe according to the present invention. FIG. 1 (a) is a view of the round bar or the steel tube viewed from the axial direction, and FIG. 1 (b) is a view of the round bar or the steel tube viewed from the circumferential direction.
In the figure, (1) is an ultrasonic probe according to the present invention,
Symbols S, B, and F in (2) to (6) and in the figure are exactly the same as those shown in FIG. FIG. 2 is a detailed view of the ultrasonic probe (1) according to the present invention. FIG. 2 (a) is a view of the round bar steel or the steel tube material viewed from the axial direction,
FIG. 2 (b) is a view of the round bar steel or the steel pipe material as viewed from the circumferential direction. In the figure, (7) is an attachment, (8) is an outer surface of the attachment (7), (9) is an ultrasonic vibrator, and X
1 is an ultrasonic transducer (9) and the outer surface of the attachment (8)
The ultrasonic beam inside the attachment (7) propagating between the attachment and (7), x2 is the ultrasonic beam in the acoustic coupling material (2) propagating between the outside surface of the attachment (8) and the round bar or steel pipe (3). , x3 are the ultrasonic beams where the ultrasonic beam x1 is reflected on the outer surface of the attachment (8), x4 is the ultrasonic beam where the ultrasonic beam x2 is reflected on the outer surface of the attachment (8), α is the ultrasonic beam x1 The angle between the attachment outer surface (8), β is the angle between the ultrasonic beam x2 and the attachment outer surface (8), and θ is the round bar steel or the outer surface of the attachment (8) of the steel pipe (3). Is the corner. FIG. 3 shows a vertical flaw detection of a round bar steel or a steel pipe material (3) by a water immersion method using a pulse reflection method in an ultrasonic flaw detector using the ultrasonic probe (1) configured as described above. Is a flaw detection figure in the case where is performed. In the figure,
(10) and the symbols S1, S2, B1-S1,...
It is exactly the same as that shown in the figure. In the ultrasonic probe (1) configured as described above, the ultrasonic vibrator (9) that transmits and receives ultrasonic waves inside the ultrasonic probe (1) is a round bar steel or a steel pipe (3). ) Has a curvature in the circumferential direction, and the attachment outer surface (8) between the ultrasonic vibrator (9) and the water as the acoustic coupling material (2) is formed of a round bar steel or steel pipe material (3). The attachment (7) which is not parallel to the outer surface in the direction, that is, the attachment (7) which forms the angle θ between the axial outer surface of the round bar steel or the steel pipe (3) and the attachment outer surface (8); The ultrasonic beam (5) generated by the ultrasonic transducer (6) in the axial direction of the round bar steel or the steel pipe (3) can be distinguished into x1, x2, x3, and x4. Here, assuming that the sound velocity v _{1 of} water as the acoustic coupling material (2) and the sound velocity v ₂ of the attachment (7),
In order for the ultrasonic beam X2 to be perpendicularly incident on the surface of the round bar steel or the steel pipe material (3), the following equations (1) and (2) hold between α, β, and θ.

β = θ (2) That is, if the equations (1) and (2) are satisfied, the ultrasonic wave is applied to the round bar steel or the steel pipe (3) regardless of the material of the attachment (7). Can be incident perpendicularly.

Next, regarding the levels of x3 and x4, which are reflected waves on the outer surface of the attachment (8), the acoustic impedance of water is Z1, and the acoustic impedance of the attachment (7) is Z2.
Assuming that 2, the reflectance r is obtained from the equation (3).

For example, if an acrylic resin is used as the material of the attachment (7) and θ = 10 °, x3, x
The reflectance of 4 is about 15%. In other words, about 8 of the ultrasonic beam x1
5% travels along with two ultrasonic beams. Ultrasonic beams x1, x2 of reflected waves from round bar steel or steel pipe material (3)
Is also the same as above.

The ultrasonic beam (5) in the circumferential direction of the round bar or the steel pipe (3) is generated by the ultrasonic vibrator (9) having a curvature in the circumferential direction of the round bar or the steel pipe (3). The effective width (6) of the beam (5) can be converged.

Next, the attenuation of the ultrasonic beam (5) will be described. The ultrasonic beam x1 is propagating inside the attachment (7). Therefore, when the attenuation of the ultrasonic wave propagating in water and the attenuation of the ultrasonic wave propagating inside the attachment (7) are compared, the attenuation constant of the material of the attachment (7) and the ultrasonic wave propagating inside the attachment (7) are naturally determined. Sound beam x1
Varies depending on the propagation distance. For example, if acrylic resin is used as the material of the attachment (7), and the propagation distance of the ultrasonic beam x1 propagating inside the attachment (7) is about 10 mm, the attenuation is about 10 dB, and the propagation in the acrylic material is attenuated. Becomes larger.

According to the above description, the ultrasonic vibrator (9) has a curvature in the circumferential direction of the round bar steel or the steel pipe material (3), and the ultrasonic vibrator (9) and the water as the acoustic coupling material (2) have a curvature. Has an attachment (7) that is not parallel to the axially outer surface of the round bar or steel pipe (3), the following is possible.

(I) The ultrasonic beam (5) is perpendicularly incident on the surface of the round bar or the steel pipe (3).

(II) By changing the material of the attachment (7) and the propagation distance of the ultrasonic beam x1 propagating inside the attachment (7), the sound pressure level is reduced by about 2 to 20 dB each time the attachment (7) is passed once. It is possible to lower the degree.

(III) Since the ultrasonic vibrator (9) has a curvature in the circumferential direction of the round bar or the steel tube (3), it is possible to converge the ultrasonic beam (5) inside the round bar or the steel tube (3). it can. This leads to an improvement in the flaw detection performance of the round bar steel or the steel pipe material (3).

According to the above (I), (II), and (III), the present invention does not lower the conventional flaw detection performance, and reflects the test material (3) by the first transmission pulse T1 as shown in FIG. This makes it possible to reduce the number of multiple echoes of the wave and shorten the repetition time t of the transmission pulse T.

In this embodiment, the attachment (7) is made of an acrylic resin. However, the same effects can be obtained with other resins and plastics, so that the present invention is inevitably applied.

FIG. 4 is a diagram showing another embodiment of the ultrasonic flaw detector using the ultrasonic probe according to the present invention. FIG. 4 (a) is a view of the round bar steel or the steel tube material as viewed from the axial direction.
FIG. 4 (b) is a view of the round bar steel or the steel pipe material as viewed from the circumferential direction.

In the figure, (1) is an ultrasonic probe according to the present invention,
Symbols S, B, and F in (2) to (6) and in the figure are exactly the same as those shown in FIG. FIG. 5 is a detailed view of the ultrasonic probe (1) shown in FIG. FIG. 5 (a) is a view of the round bar steel or the steel tube material viewed from the axial direction,
FIG. 5 (b) is a view of the round bar steel or the steel pipe material as viewed from the circumferential direction. In the figure, (7) is an attachment, (8) is an outer surface of the attachment (7), (9) is an ultrasonic transducer for transmitting and receiving ultrasonic waves inside the ultrasonic probe (1), x
1 is an ultrasonic transducer (9) and the outer surface of the attachment (8)
The ultrasonic beam inside the attachment (7) propagating between the attachment and (7), x2 is the ultrasonic beam in the acoustic coupling material (2) propagating between the outside surface of the attachment (8) and the round bar or steel pipe (3). , x3 are the ultrasonic beams where the ultrasonic beam x1 is reflected on the outer surface of the attachment (8), x4 is the ultrasonic beam where the ultrasonic beam x2 is reflected on the outer surface of the attachment (8), α is the ultrasonic beam x1 The angle between the attachment outer surface (8), β is the angle between the ultrasonic beam x2 and the attachment outer surface (8), and θ is the round bar steel or steel pipe material (3) surface and the attachment outer surface (8). Is the corner.

In the ultrasonic probe (1) configured as described above, an ultrasonic transducer (9) for transmitting and receiving ultrasonic waves inside the ultrasonic probe (1) and an acoustic coupling material (2). An attachment (7) whose outer surface (8) between a certain water is not parallel to the axial outer surface of the round bar or steel tube (3) but has a curvature in the circumferential direction, that is, a round bar or steel tube When an attachment (7) having a curvature in the circumferential direction and converging the ultrasonic beam (5) is formed at an angle θ between the outer surface in the axial direction of (3) and the outer surface of the attachment (8), In the axial direction of the steel bar or steel pipe (3),
The ultrasonic beam (5) generated by the ultrasonic transducer (6) can be distinguished into x1, x2, x3, and x4. Assuming that the sound velocity of water as the acoustic coupling material (2) is v ₁ and the sound velocity of the attachment (7) is v ₂ , in order to make the ultrasonic beam x2 perpendicularly incident on the surface of the round bar steel or the steel pipe (3) , Α,
Equations (1) and (2) hold between β and θ.

That is, if the expressions (1) and (2) are satisfied, the ultrasonic wave can be vertically incident on the round bar steel or the steel pipe material (3) whatever the material of the attachment (7). .

Next, regarding the levels of x3 and x4, which are reflected waves on the outer surface of the attachment (8), the acoustic impedance of water is Z1, and the acoustic impedance of the attachment (7) is Z
Assuming that 2, the reflectance r is obtained from the above equation (3).

For example, if an acrylic resin is used as the material of the attachment (7) and θ = 10 °, x3, x
The reflectance of 4 is about 15%. In other words, about 8 of the ultrasonic beam x1
5% travels along with two ultrasonic beams. Ultrasonic beams x1, x2 of reflected waves from round bar steel or steel pipe material (3)
Is also the same as above.

Next, the attenuation of the ultrasonic beam (5) will be described. The ultrasonic beam x1 is propagating inside the attachment (7). Therefore, when the attenuation of the ultrasonic wave propagating in water and the attenuation of the ultrasonic wave propagating inside the attachment (7) are compared, the attenuation constant of the material of the attachment (7) and the ultrasonic wave propagating inside the attachment (7) are naturally determined. Sound beam x1
Varies depending on the propagation distance. For example, if an acrylic resin is used as the material of the attachment (7) and the propagation distance of the ultrasonic beam x1 propagating inside the attachment (7) is about 10 mm, it is about 10 dB, and attenuation when propagating in the acrylic material is attenuated. Becomes larger.

According to the above description, the attachment outer surface (8) between the ultrasonic transducer (9) and the water as the acoustic coupling material (2) is parallel to the axial outer surface of the round bar steel or the steel pipe (3). Instead, the following can be achieved by providing an attachment (7) having a curvature in the circumferential direction.

(I) The ultrasonic beam (5) is perpendicularly incident on the surface of the round bar or the steel pipe (3).

(II) By changing the material of the attachment (7) and the propagation distance of the ultrasonic beam x1 propagating inside the attachment (7), the sound pressure level is reduced by about 2 to 20 dB each time the attachment (7) is passed once. It is possible to lower the degree.

(III) The outer beam (8) of the attachment has a curvature in the circumferential direction of the round bar or the steel pipe (3), so that the ultrasonic beam (5) inside the round bar or the steel pipe (3) can be focused. . This is a round bar or steel pipe (3)
This leads to improved flaw detection performance.

According to the above (I), (II), and (III), the present invention does not lower the conventional flaw detection performance, and reflects the test material (3) by the first transmission pulse T1 as shown in FIG. This makes it possible to reduce the number of multiple echoes of the wave and shorten the repetition time t of the transmission pulse T.

In the above other embodiments, the material of the attachment (7) is made of acrylic resin. However, the same effects can be obtained with other resins and plastics, so that the application of the present invention is inevitable.

〔The invention's effect〕

As described above, according to the present invention, the ultrasonic vibrator has a curvature in the circumferential direction of the round bar or the pipe material, and the outer surface of the attachment between the ultrasonic vibrator and the water as the acoustic coupling material has a round bar or a round bar. By providing an attachment that is not parallel to the axial outer surface of the tube, it is possible to shorten the repetition time t of the transmission pulse T without lowering the conventional flaw detection performance, shorten the processing time for the test material, and This has the effect of increasing the flaw detection density.

According to another aspect of the present invention, as described above, the outer surface of the attachment between the ultrasonic vibrator and the water as the acoustic coupling material is not parallel to the axially outer surface of the round bar or the tube, and Equipped with an attachment having a curvature in the circumferential direction of the round bar or the tube material, it is possible to shorten the repetition time t of the transmission pulse T without lowering the conventional flaw detection performance, and to shorten the processing time for the test material. ,
This also has the effect of increasing the flaw detection density and enabling high-speed flaw detection and density flaw detection.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an ultrasonic flaw detector using the ultrasonic probe of the present invention, FIG. 2 is an enlarged view of the ultrasonic probe of the present invention, and FIG. FIG. 4 is a diagram showing another embodiment of the present invention, FIG. 5 is an enlarged view of the ultrasonic probe of FIG. 4, and FIG. 6 is an ultrasonic probe using a conventional ultrasonic probe. FIG. 7 shows an ultrasonic flaw detector, and FIG. 7 shows a flaw detection pattern in an ultrasonic flaw detector using a conventional ultrasonic probe. In the figure, (1) is an ultrasonic stylus, (2) is an acoustic coupling material, (3) is a round bar steel or steel pipe material, (4) is a defect inside the test material, (5) is an ultrasonic beam, (6) is an effective width of the ultrasonic beam (5), (7) is an attachment, (8) is an outer surface of the attachment, (9) is an ultrasonic oscillator, and (10) is a flaw detection gate. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

(57) [Claims] An ultrasonic probe for vertically flaw detecting a round bar or a tube by a water immersion method, wherein the ultrasonic transducer for transmitting and receiving ultrasonic waves inside the ultrasonic probe is the round bar or the ultrasonic probe. Attachment having a curvature in the circumferential direction of the pipe material, the attachment outer surface of which is not parallel to the axial outer surface of the round bar or the pipe material, between the ultrasonic vibrator and water which is an acoustic coupling material in the water immersion method. An ultrasonic probe characterized by having an equipped octopus. 2. An ultrasonic probe for detecting flaws on a round bar or a pipe vertically by a water immersion method, comprising: an ultrasonic transducer for transmitting and receiving ultrasonic waves inside the ultrasonic probe; The outer surface of the attachment between the water and the acoustic coupling material is not parallel to the outer surface of the round bar or the tube in the axial direction, and has an attachment having a curvature in the circumferential direction of the round bar or the tube. An ultrasonic probe characterized by the following.