JPS59148866A - Ultrasonic flaw detecting method of round steel bar - Google Patents

Abstract

PURPOSE:To simplify a flaw detecting mechanism and to improve flaw detection efficiency by fitting a tapered array probe concentrically around a round steel bar as a material to be detected, and transmitting and receiving an ultrasonic wave which slants to the axial center of a round steel bar by rectangular oscillation element of the probe and making an electron scan. CONSTITUTION:The tapered array probe 1 where rectangular oscillation elements 3 are arranged annularly so that the internal surface is a tapered surface with a specific angle alpha is fitted around concentrically around the round steel bar 4 as the material to be detected; a specific predetermined number M of elements 3 among the elements 3 of the probe 1 are used and the ultrasonic wave converged with specific delay time T is transmitted and received by every element. Then, the transmitting/receiving position is shifted at predetermined scanning pitch P and the round steel bar 4 is moved straight to perform the surface wave flaw detection of a defect over the entire surface of the round steel bar 4. Consequently, the flaw detection mechanism is simplified to improve to improve the flaw detection efficiency.

Description

[Detailed description of the invention] The present invention relates to an ultrasonic flaw detection method for round bars.

Conventionally, magnetic flaw detection has been used for surface flaw detection of round bars, ultrasonic angle flaw detection has been used for surface layer flaw detection, and ultrasonic vertical flaw detection has been used for internal flaw detection. In these methods, in order to detect surface defects and surface layer defects over the entire circumference of the round bar,
The flaw detection heads of surface defect flaw detection devices and surface layer flaw detection devices must be fixed and the material to be inspected must be fed in a spiral manner, or the flaw detection head must be rotated to move the material to be inspected straight. Furthermore, in the ultrasonic angle flaw detection of the surface layer, it is necessary to take the directionality of the defect into account and apply ultrasonic waves from two directions, which requires two probes. To detect internal defects over the entire length, a flaw detection head with multiple vertical probes is fixed and moved straight through the material to be inspected, or a flaw detection head with one or more vertical probes is It was necessary to rotate the flaw detection head or feed the material to be tested in a spiral manner.

' In the conventional flaw detection method described above, high-speed scanning is impossible because mechanical scanning is performed by rotating the flaw detection head, spiral feeding of the test material, etc., and the structure of the flaw detection apparatus becomes complicated. In addition, when changing the size (diameter, etc.) of the material to be tested, in conventional flaw detection methods, the size range that can be handled with one type of probe holder is narrow, and in order to detect flaws in a wide range of sizes, multiple types of probes are required. It was necessary to prepare a secondary holder, and it took time to reassemble the flaw detection head.

Furthermore, surface flaw detection, surface layer flaw detection, and four-part flaw detection cannot be performed using the same probe, and scanning must be performed using each device.

Therefore, in order to solve the above-mentioned problems, the applicant of the present application previously proposed the use of an electronic scanning type annular array probe in Japanese Patent Application No. 8198/1983.

However, since the annular array probe injects ultrasonic waves parallel to the cross section of the round bar, it is difficult to detect defects having a direction perpendicular to the longitudinal force of syncope.

Therefore, the present invention is an improvement on the previously proposed invention, and is capable of detecting defects in any direction, and eliminates the need to rotate the flaw detection head or round bar by electronic scanning. The purpose of this test is to simplify the device mechanism, improve inspection efficiency by enabling high-speed scanning and composite flaw detection, and facilitate handling when changing the size of the test material.

In order to achieve the above object, the present invention is characterized in that a tapered array probe in which rectangular vibrating elements are arranged in an annular manner so that the inner surface has a tapered surface at a predetermined angle is used on a material to be examined. The purpose of this method is to detect flaws in a round bar by fitting it concentrically through the outside of a round bar and electronically scanning it by sending and receiving ultrasonic waves tilted to the axis of the bar using the element of the probe.

First, the Dever-shaped array probe used in the wood invention will be explained.

As shown in FIGS. 1 to 8, the tapered array rod (1) has rectangular vibration elements (3) arranged in an annular manner on the inner surface of a cylinder (2). The rectangular vibrating element (3) is arranged so as to form a tapered surface of the probe (with the inner surface of the probe at a predetermined angle). The round bar marked with d in the figure is the test material (
4), D indicates the small inner diameter of the probe (1),
W indicates the width of the vibrating element (3), day indicates the space between each element (3), and L indicates the length of the element (3).

The tapered array probe (1) is fitted concentrically through the round bar (4), and electronic scanning is performed over a wide area of the round bar (4) by moving the round bar (4) in a straight line. It is possible to detect flaws over a period of time.

Next, we will first explain the ultrasonic beam based on the principle of electronic scanning used in the present invention. As shown in FIG. The beam is transmitted and received by adjusting the timing of the transmission and reception of the beam using a delay time control circuit. Figure 4 (a
), if the delay time is not set, a wavefront (5) equivalent to the wavefront from a single large-diameter transducer is formed, but depending on the method of setting the delay time (T), the wavefront as a whole of the transducer The beam can be tilted (Figure 4 (1)), narrowed (Figure 4 (C)), or narrowed and tilted (Figure 4 (d)).
))be able to.

Such an electronic scanning transducer has a variety of elements (3) in one
Since they are operated simultaneously as a set, the whole is the same as a large-diameter vibrator, and has sharp directivity.

Furthermore, by giving a predetermined delay time to the transmitted and received signals, the electronic scanning transducer can narrow the beam and increase the resolution, similar to concave transducers and lens-equipped transducers. Since this focal length can be set arbitrarily, by converging the beam on the flaw detection area in the test material, it is possible to improve the accuracy of detecting minute defects, and at the same time, the accuracy of estimating the defect position is also improved.

Note that the beam used for the wood invention is
These are the beams shown in Figures (a) and 4(C).

Next, the direction in which the beam is emitted will be explained. As shown in FIG. 5, the beam is emitted at a predetermined angle of inclination with respect to the axis of the round bar (4). If the beam is emitted parallel to the cross section of the round bar (4), as shown by the imaginary line in FIG. 6, it will be difficult to detect defects (6) in a direction perpendicular to the axial direction. Therefore, in the present invention, in order to eliminate this drawback, the beam is transmitted at an angle to the axis. For this purpose, the vibrating element (3) is arranged in a tapered shape.

The taper angle (→) differs depending on the surface flaw detection, surface layer flaw detection, and internal flaw detection described below.

Next, scanning for detecting flaws on the entire surface or expanded cross section of the round bar (4), which is the test material, which is fitted inside the tapered array probe (1) K concentrically will be explained.

This scanning is performed according to the principle of electronic linear scanning shown in FIG. The figure shows a linear array probe (1) with a total of 64 elements and a linear array probe (3) with a total of 16 elements.
This shows the principle of linear scanning as a set, and #! FIG. 6(a) shows the initial state, and FIG. 6(b) shows the state where the transmitting/receiving element (3) is shifted by one. In the figure, (7) indicates a transmitter/receiver, (8) a delay circuit, and (9) a reed relay circuit (changeover switch). As is clear from FIG. 6, electronic linear scanning uses the delay time control circuit (
In addition to step 8), the ultrasonic beam is scanned at a predetermined pitch by sequentially shifting the transmitting and receiving elements (3) using a changeover switch (9).

Therefore, by shifting the transmitting/receiving bare hand position at a predetermined scanning pitch, it is equivalent to moving the element over the entire inner part of the tapered array probe (1). Area can be scanned at high speed.Round bar (
4), the round bar (4) is moved straight in the axial direction.

The tapered array probe (1) can perform either surface flaw detection, surface layer flaw detection, or internal flaw detection of the material to be tested (4), as well as a combination of surface layer flaw detection and internal flaw detection. Composite flaw detection can also be performed simultaneously using one annular array probe (11).

In other words, in order to perform complex flaw detection, the characteristic of array type probes, which is the ability to freely perform ultrasonic beam forming, is applied.
As shown in FIG. 7, the settings of the excitation element position, number, and delay time of each element for each excitation pulse DI are as follows:
For example, by alternating the setting pulse (11) for surface layer flaw detection and the setting pulse α2 for internal flaw detection, it is possible to simultaneously perform flaw detection on the surface layer (Fig. 8) and inside (Fig. 9) using the same probe. .

Next, each embodiment of the present invention will be described.

<First Example> In this first example, a tapered array probe (1) in which rectangular vibrating elements (3) are arranged in an annular shape so that the inner surface has a tapered surface with a predetermined angle (α) is used. Round bar (4) to be inspected
A predetermined number of elements (3) are used among the elements (3) of the probe (1), and a predetermined delay time (T) is used for each element. ) to transmit and receive converged ultrasonic waves, shift the transmitting and receiving element position at a predetermined scanning pitch (P), push the round bar (4) straight, and press the round bar (
4), defects on the entire surface are detected using surface waves.

The tapered array probe (1) has a frequency of 5 MH
2.

Probe inner diameter D =: 15QllN, element width W = 1.0
space between elements S = 0.05g, element length n = 2
I am using one from 0.

According to Figure 10, the taper angle (c) of the probe (1)
To explain this, the refraction angle of the round bar (4) (therefore, the taper angle (b) of the probe (1) when introducing sound waves) can be determined by the following equation.

αko2X grn −” (”subθ) ・・・・・・・・・
...■2 C1; Sound speed of the incident side medium C2; Sound speed of the refracting side medium Therefore, in the case of surface wave flaw detection in this first embodiment,
The conditions for surface waves to occur are when the refraction angle is 90 degrees, and if the water immersion method is used, the underwater sound velocity is 01 = 1.
481*/μ, so the surface wave sound velocity of steel is 0z=2.
Using the equation 98/μ, we get the formula ■Stever angle (b)
α=:2sin-' (objective image 90°) = 59.6°2.98.

Next, the flaw detection size that can be detected by the probe (1), that is, the diameter (d) of the round bar (4) will be explained.

The diameter (, i) of the round bar (4) is limited by the following conditions.

(1) +St echo appears beyond the flaw detection range.

(!l) The flaw detection range must be within the directivity angle of each element.

First, if we apply the condition (1) to the case of surface wave flaw detection according to Fig. 11, since surface waves are highly attenuated in water, the flaw detection range is δ-10 to 15 fl from the sound wave incidence point of the test material (4). Then, the water distance (H) is □=δ5-knee15
×18=,MC! , 2.98 or more is required. Therefore, the diameter (d) of the round bar is d≦2
X (T -H Masho 1) = 2 rivals -1507, 4 fish 29.8 °)
=187ho1; Must be the angle of incidence.

Next, it would be difficult to apply condition (II), but this condition is related to the number of elements used (b), that is, the number of elements in the vibrator (B) shown in FIG. 12.

On the other hand, in flaw detection, a convergent beam is used to detect minute defects with good S'/N. The number of elements to be used (b) must be selected so that n=F/2 in terms of conversion distance.

Now, the directivity angle φ) of 8 dB down for a single element is 〒-
It is expressed as β≦1.89. Focus point is 8dB of each element (3)
To be within the directivity angle of down, there must be −=−β two people.

Further, xo; near-field sound field limit distance 1.85; since this is a correction coefficient for changing the circular vibrator to a rectangular vibrator, eL < 185 mm. (See Fig. 11 φ Fig. 12) That is, the diameter (a) of the tapered array probe (round bar (4) capable of surface wave flaw detection with 1 inch is the diameter (a) of the above (+) (1)
Based on the conditions, the d product is 20mm to 180mm, and the same probe (1) can be used over a very wide range of round rods (4).
can be detected.

Therefore, there is no need to change the flaw detection heads in different ways depending on the flaw detection size, as in the past.

Next, to explain the length of one element (3), let us assume that the standardized distance is n''F 1, and in Fig. 11, f=x6
Then L can be found in the same manner as when B was found above. According to this, L=9.4-8.7ff (d=20-180+lf*).

Next, in this surface wave flaw detection, the predetermined number (b) of elements (3) used in electronic scanning, that is, the aforementioned probes as one set, is determined as follows.

As mentioned above, in order to detect minute defects with a good /N (signal to noise ratio), a focused beam (the beam shown in Figure 4 (0)) is used, and in order to obtain a focused beam in the flaw detection area (■), Focus on the center of the flaw detection area (3). For this purpose, the number of elements used (
assets).

Therefore, the required transducer width (element width of one set) B is: B = 12.6 mm (a = 201ffi) ~ 7.0 Wf
f (d, = 180) and p1 Therefore, W = 1.0
Since it is MM, the number of elements used (6) is M = 12 (tl = 20) to 7 (cl = 1).
80 order).

Next, the predetermined scanning pitch (P) is indicated by the shift amount of the used element position, and since surface waves are highly attenuated in water, the scanning pitch (P) is determined in advance within a range of IBg ~ 15 m from the point of incidence of the sound wave on the test material (4). If the flaw detection area is 8 dB down and the beam width is 8 dB down, the shift amount N is 1 element/shift (220 to 180 flaws).

That is, by performing electron jJ near scanning at the above scanning pitch (P=N), the entire circumferential area can be inspected, and by moving the round bar (4) straight, it is possible to detect flaws on the entire surface of the round bar (4). Defects can be detected.

Here, to explain the reason why surface waves are used for surface flaw detection, the energy of surface waves is concentrated in several wavelengths below the surface, so it is suitable for detecting open flaws (surface defects) on the surface. This is because there is no other method for detecting only surface defects using ultrasonic flaw detection.

As described in detail above, according to the first embodiment of the present invention, since the tapered array probe (1) having a predetermined angle (B) is used, it is inclined with respect to the axis of the round bar (4). Since the flaws are detected using an ultrasonic beam, it is excellent in detecting surface defects perpendicular to the longitudinal direction of the round bar (4). Because of the twisted electronic scanning, there is no need to mechanically rotate the flaw detection head and the test material, and it is only necessary to move the round bar (4) straight, so the flaw detection apparatus can be simplified.

Furthermore, since there is no mechanical scanning, high-speed scanning is possible.
This will improve flaw detection efficiency. Also, the same probe, child (1
) has an extremely wide range of flaw detection sizes, so it is possible to
Even if the diameter (d) of 4) is changed, the same probe (1)
You can respond with

<Second Example> In this second example, surface defects on a round bar (4) are detected by surface waves using the tapered array probe (1) shown in the fourteenth example. However, the electronic scanning method is
- This is different from the first embodiment.

That is, the electronic scanning of this second embodiment uses a predetermined specific number (b) of the elements (3) of the probe (1), and a predetermined delay time (T) for each element. ) is transmitted and focused ultrasonic waves are received by all elements (3), and flaw detection is performed by shifting the transmitting element position at a predetermined scanning pitch ψ).

The predetermined numerical value of the element (3)) and the scanning pitch (P) are the same as in the first embodiment.

According to this second embodiment, as shown in FIG. 18, since reception is performed by all the elements (3), surface defects that are tilted to some extent from the direction perpendicular to the longitudinal direction of the round bar (4) are also eliminated. When it is detected, it can be detected. Other effects are the same as those of the first embodiment.

Eighth Example In this eighth example, a tapered array probe (1) is used to perform oblique angle detection of minute defects (subcutaneous defects) in the surface layer of a round bar. Electronic scanning of the probe (1) is performed in the same manner as in the first embodiment.

Taper angle ol of probe (1) for surface layer flaw detection
= 1.48-litre (underwater sound speed), Oz = 8jl l
Since it is ug/p sec (transverse wave sound velocity in steel), it is determined as follows from the above formula (■). .

α= 2 m-” (-dn 45°) = 88j!
'8.2 Therefore, the taper angle (b)) of the probe J:F-(1) is different between the surface wave flaw detection described above and the surface layer flaw detection of this eighth embodiment. . However, the probe inner diameter D
"150 m, element width W = 1.0 m, inter-element space s = 0.05 vg, and frequency 5 MHz are the same as those described above.

Next, the diameter (11) of the test material (4) that can be detected in the case of surface layer flaw detection is determined. Applying the condition (1) above, "Echo should come out beyond the flaw detection range."
During surface layer flaw detection, transverse wave oblique angle flaw detection is performed with a refraction angle θ = 45°, so according to Fig. 14, ゛ = "°°" 7 doors), °, d≦67fl.

According to the above-mentioned condition (I), -β=B/2 people. Therefore, calculation can be made in the same manner as in the first embodiment, and d≦150 m.

Therefore, according to the conditions of (1) and (1), d = 20 to 65 fi.9, with the same probe (1), the round bar (4)
can be detected.

Next, to explain the element length L), if calculations are made in the same manner as in the first embodiment described above, and f is in accordance with FIG. 14, then L = 11.7 zw ~ 15.2
sw (cl = 20-66g111).

The predetermined number of elements (b) for electronic scanning can be found in the same manner as in the first embodiment, as follows: B = is, 1f
f((1=2011) ~18.71g(d=65ff
) M=16 to 18.

If the scanning pitch (P) is also determined in the same manner as in the first embodiment, the shift amount N=1 element/shift (a=2 osrg) to 8 elements/shift (cl=65 sheaths).

By performing electronic linear scanning at the above scanning pitch (P=N), the entire surface layer of the round bar in the circumferential direction can be inspected for flaws.

Here, the reason why the transverse wave angle method is used for surface layer flaw detection will be explained.

Conventionally, the vertical ultrasonic flaw detection method has been applied to detect internal defects in round bars.
Bl), the area near the surface becomes a dead zone. However, when using the angle angle flaw detection method, as shown in Figure 16, the reflected echo from the ultrasonic incident surface (El t) remains considerably, but the reflected echo from the side surface of the round bar propagates downward. Therefore, there is no dead zone caused by reflected echoes on the sides.

Therefore, defects in the surface layer in a cross section can be detected by performing oblique flaw detection by converging the ultrasonic beam.

Although FIGS. 15 and 16 are explained using cross sections perpendicular to the axis, the same applies to cross sections including the axis in the present invention.

The reason why a transverse wave is used at a refraction angle of 45° is as follows.

As shown in Fig. 16, the detection area during surface layer flaw detection is near the first reflection point (point F), and echoes due to minute irregularities on the surface of the steel bar are returned from point F. Echoes become noise during surface layer flaw detection. The results of measuring the relationship between such noise and the refraction angle show that when the refraction angle is 85° or less, noise due to the surface shape increases rapidly, but when the refraction angle is 40° or more, the twin echo is low and remains almost constant. By the way, in order to increase the refraction angle, it is necessary to increase the oscillation p angle α, which is limited by the directivity angle of the p1 single element, so the appropriate refraction angle is about 45°.

With a refraction angle of 46°, to generate a longitudinal wave, the incident angle is 1002°, and to generate a transverse wave, the incident angle is 19.1°.
must be done. Incidentally, the smaller the angle of incidence, the larger the surface echo, and the smaller the angle of incidence, the greater the influence of the spread 9 of the surface echo due to surface roughness. Therefore, we adopted transverse waves to reduce the surface dead zone caused by the spread of surface echoes.

According to the eighth embodiment, since the tapered array probe (1) at a predetermined angle (→) is used, flaws are detected with an ultrasonic beam tilted with respect to the axis of the round bar (4). Round bar(
4) Excellent in detecting surface layer defects perpendicular to the longitudinal direction. Further, since electronic scanning is performed, there is no need to mechanically rotate the flaw detection head and the test material, and it is only necessary to move the round bar (4) straight, so the flaw detection apparatus can be simplified. Furthermore, since mechanical scanning is not performed, high-speed scanning is possible and flaw detection efficiency is improved. In addition, since the same probe (1) can detect a wide range of flaw sizes, the same probe (1) can handle changes in the diameter ((1) of the material to be tested (4). In addition, because it performs transverse wave oblique angle flaw detection, flaw detection can be performed without a dead zone.

<Fourth Example> This fourth example detects internal defects in a round bar (4), and the scanning method is substantially the same as that of the eighth example.

The difference from the eighth embodiment is the range of the diameter (d) of the round bar (4) that can be detected with the same probe (1), the number of elements (b) predetermined in electronic scanning, and the scanning pitch (t). ), and the long ribs of the element.

First, as shown in Fig. 17, the diameter (d) of the round bar (4) that can be detected is (C1 = 1.4811! l/μ.O, = 8.24). V
μ. D = 150 fins.

1=19.1°) Yes, d≦92.

Also, according to the above condition (1), -β=/2A kW.

One measurement β≦1.89 Therefore, d≦150 silk.

Therefore, the condition of (+) (I), 9 d ~ 20 ~ 9
It becomes 011111.

The length L) of the element is L=11.9~x4j! am(a=
20~g□rg).

Next, the predetermined number of elements (goods) is: s = i8j! , wg (a=2om) ~10.5
srm (d, = 9otxm), so M = 18 pieces ('d = 20ml) ~ 10 pieces ((1 = 9
0ff).

The scanning pitch (P) is as follows: shift amount N=1 element/shift (a=2om) to 8 elements/shift (d=90ffff).

<Fifth Example> In this example, a tapered array probe (1) in which rectangular vibrating elements (3) are arranged in an annular shape so that the inner surface has a tapered surface at a predetermined angle (α) is used with a material to be tested. A round bar (4) is fitted concentrically through the outside, and ultrasonic waves are transmitted and received by all the vibrating elements (3) from a direction inclined to the axis, and defects inside the round bar (4) are removed at an oblique angle. It is used for flaw detection.

The tapered array probe used for this, the fourth
This is the same as the example. If we take the specifications as 1, D=150ffff, W=1.0W, S=0.05
1'l.

α=88.2° L=11.9-142.

According to this fifth embodiment', as shown in FIG. 18, when there is an internal defect (6) perpendicular to the axis, all the elements (3) transmit and receive ultrasonic waves, The reception sensitivity is better than in the fourth embodiment, and defects can be detected reliably.

In the case of detecting an internal defect, since estimation of its position is not important, it is sufficient to detect only whether or not a defect exists by transmitting and receiving signals from all elements. However, in surface and surface layer defect detection, since detection of the position is important, the positional relationship between the transmitting element and the receiving element is required, so it is not preferable that all elements transmit and receive. but,
If only the presence or absence of a defect is to be detected, the Kinio side can also be applied to the above-mentioned surface and surface layer defect detection.

<Sixth Example> C17) The sixth example is a composite flaw detection in which one tapered array probe (1) is used to simultaneously perform surface layer flaw detection and internal flaw detection.

In this case, flaw detection by electronic scanning uses a predetermined number of elements (3) of the elements (3) of the probe (1), and a predetermined delay time (T) for each element. A probe (1) that transmits and receives converged ultrasonic waves by giving a certain amount of force and shifts the transmitting and receiving element position at a predetermined scanning pitch (P), and performs oblique angle flaw detection on the surface layer of a round bar; Using a predetermined specific number (b) of the elements (3), converged ultrasonic waves are transmitted and received with a predetermined delay time (T) given to each element, and a predetermined scanning pitch ( By shifting the position of the transmitting and receiving element in P), performing oblique angle detection of defects inside the round bar (4); By repeating in a predetermined sequence, all defects can be detected with one probe (1). This is a composite flaw detection method that performs cross-sectional flaw detection.

That is, the electronic scanning according to the eighth embodiment and the fourth embodiment are repeated in a predetermined sequence.

According to the sixth embodiment, flaw detection can be performed on the surface layer and inside at the same time using one probe (1), and the flaw detection efficiency is improved.

<Seventh Example> This is a single tapered play by repeating the surface layer flaw detection according to the eighth example and the internal flaw detection using all the elements according to the fifth example in a predetermined sequence. The probe (1) performs surface layer flaw detection and internal flaw detection simultaneously.

<Eighth Example> As shown in FIG. 19, this eighth example uses the surface defect detection probe (1
) and the surface layer defect detection probe (1) of the eighth embodiment are arranged in series, and each probe (1) (13K) is used to detect surface defects and surface defects of the round bar (4). This is a composite flaw detection method that detects layer defects and then differentiates between surface defects and surface subcutaneous defects based on the flaw detection results.

Generally, when the surface layer is detected by angle angle flaw detection, surface defects are also detected, so it is difficult to determine whether the detected defect is a subcutaneous defect.
It is difficult to determine whether it is a surface defect. Therefore, the surface defect is detected by the surface defect detection probe (1) according to the first embodiment or the second large flow example, and the detection information 03 and the surface layer defect detection probe (1) according to the eighth embodiment are used. By subtracting the detection information α→ of the surface layer defect+subcutaneous defect detected in (1) using the arithmetic processing unit α9, only the subcutaneous defect can be discriminated and detected.

<Ninth Example> As shown in FIG. 20, a surface wave flaw detection probe (1) according to either the first or second example and an internal flaw detection probe (1) according to the fourth example are used. This is a composite flaw detection method in which surface flaw detection and internal flaw detection are performed simultaneously by arranging 1) in series.

<Tenth Example> As shown in FIG. 21, the surface wave flaw detection probe (1) according to either the first example or the second example and the surface wave flaw detection probe (1) according to the sixth example or the seventh example Layer + internal flaw detection probe (1)
are arranged in series, and the entire cross section of the round bar (4) is inspected for flaws.
Based on the flaw detection results, surface defects, surface subcutaneous defects, and internal defects are discriminated and detected.

Note that the present invention is not limited to each of the above embodiments.

According to the present invention, the flaw detection device mechanism can be simplified and the flaw detection efficiency can be improved. These effects become even greater during complex flaw detection. Furthermore, in terms of flaw detection performance, it is excellent in detecting minute defects, especially defects perpendicular to the longitudinal direction.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the tapered array probe used in the present invention, Fig. 2 is a view taken along the ■-■ arrow in Fig. 1, Fig. 8 is an enlarged view of the ■ part in Fig. 2, and Fig. The figure is an explanatory diagram showing the principle of electronic scanning, Fig. 5 is an explanatory diagram showing the emission direction of the ultrasonic beam, and Fig. 6 is an explanatory diagram showing the emission direction of the ultrasonic beam.
The figure is an explanatory diagram showing the principle of electronic linear scanning, Fig. 7 is an explanatory diagram showing the relationship between complex flaw detection and pulses, Fig. 8 is a conceptual diagram showing surface layer flaw detection-1, and Fig. 9 is a conceptual diagram showing internal flaw detection. 10th
The figure is an explanatory diagram of the taper angle setting of a tapered array probe, Figures 11 and 12 are explanatory diagrams for determining the diameter of a round bar in surface flaw detection, and Figure 18 is a circumferential development diagram of the round bar. Fig. 14 is an explanatory diagram for determining the diameter of a round bar in surface layer flaw detection, Figs. FIG. 18 is a diagram for explaining the effects of the fifth embodiment, and FIGS. 19 to 21 are block diagrams showing the eighth to tenth embodiments, respectively. (1)...Tapered array probe, (3)...Element, (4)...Round bar, (→...Taper angle, (c)
)...Number of elements in 1 set, ψ)...Scanning pitch. Figure 3 ・ Figure 6 □ Figure 4 □ (a) (b) (C)
(d) Figure 7 Figure 8 Figure 9 Figure 5 Procedures Amendment (voluntary) March 1, 1980 Mr. Commissioner of the Japan Patent Office 1, Indication of the case 1982 41゛ Patent application No. 23528 2 Invention Name: Round bar ultrasonic detection S method 3, relationship with 111 amendments Patent applicant/1 agent Address: 1013 Mikuriya, Higashiosaka 1r, Osaka Telephone: Osaka 40
617R21 (! Bi K! Showa year month
(Voluntary) 6 The target bow of the supplementary iE is m-1 C'-Tobimachi 7H7, Contents of the amendment 11) ``Proposed first...'' on page 6, lines 10-12 of the specification. ...can be corrected to ``can detect defects (such as cuppy cracks and chevron cracks) tilted from the longitudinal direction of round bars, which are difficult to detect with the previously proposed invention.'' (21, page 7, line 12, “small inner diameter”; “center inner diameter”)
(3) Same, page 16, lines 3 to 9, "Next...
...becomes. ” to be deleted. (4) Same, 22nd member, lines 1 to 4, “Next...
...becomes... ” to be deleted. (6) Same, page 25, lines 15-16, [and the length of the element] are deleted. (61, page 26, lines 6-7 from the bottom, "The length D of the element is in the order of L = 11.9-14.2 (d〒20-90
Fight) yell. ” to be deleted. (7) Same, page 27, line 16, “L=11.9~
Correct it as 14°2 tm J tr L = 20wjRJ. 181 Corrections will be made as shown in the appendix for Figures 3, 5, 11, 14, and 17 of the drawings.

Claims (1)

[Claims] 1. A tapered array probe in which rectangular vibrating elements are arranged in an annular shape so that the inner surface is tapered at a predetermined angle,
The rod is fitted concentrically through the round rod to be inspected, and the element of the probe sends and receives ultrasonic waves tilted to the axis of the rod to perform electronic scanning, thereby detecting flaws in the rod. Ultrasonic flaw detection method for round bars. 2. Flaw detection by electronic scanning uses a predetermined number of elements among the elements of the probe, transmits and receives ultrasonic waves that are converged with a predetermined delay time given to each element, and performs a predetermined scan. The ultrasonic flaw detection method for a round bar according to claim 1, wherein defects on the entire surface of the round bar are detected by surface waves by shifting the positions of the transmitting and receiving elements at pitches. 8. Flaw detection by electronic scanning, using a predetermined number of elements among the elements of the probe, transmitting focused ultrasonic waves for each element (given a predetermined delay time), The round bar according to claim 1, wherein defects on the entire surface of the round bar are detected by surface waves by receiving signals and shifting the position of the transmitting element at a predetermined scanning pitch. Ultrasonic flaw detection method. 4. Flaw detection by electronic scanning uses a predetermined number of elements in the probe, and transmits and receives focused ultrasonic waves with a predetermined delay time for each element. The round bar according to claim 1, wherein fine defects on the entire surface layer of the round bar are detected at an oblique angle by shifting the transmitting/receiving element position at a predetermined scanning pitch. Ultrasonic flaw detection method for rods. 5. Flaw detection by electronic scanning uses a predetermined number of elements in the probe, and sends focused ultrasonic waves with a predetermined delay time for each element. Claim 1 is characterized in that the present invention is characterized in that the device transmits and receives data and shifts the position of the transmitting and receiving elements at a predetermined scanning pitch, thereby detecting defects inside a round bar at an oblique angle. Ultrasonic flaw detection method for round bars. 6. A patent characterized in that electronic scanning flaw detection involves transmitting and receiving ultrasonic waves with all elements of the probe to detect defects inside the round bar at an oblique angle. Ultrasonic flaw detection method for a round bar according to claim 1. 7. Flaw detection by electronic scanning uses a predetermined number of elements among the elements of the probe, and a predetermined delay time for each element. The surface layer of a round bar is inspected at an oblique angle by transmitting and receiving focused ultrasonic waves at a predetermined scanning pitch and by shifting the transmitting and receiving element position at a predetermined scanning pitch; Using a specific number of elements, each element transmits and receives focused ultrasonic waves with a predetermined delay time, and by shifting the positions of the transmitting and receiving elements at a predetermined scanning pitch, defects inside the round bar can be detected. The round bar according to claim 1, characterized in that it is a composite flaw detection in which flaw detection is performed on the entire cross section with one probe by repeating the following in a predetermined sequence: Ultrasonic flaw detection method. 8. Flaw detection using electronic scanning uses a predetermined number of elements in the probe, and transmits and receives focused ultrasonic waves with a predetermined delay time for each element. By shifting the position of the transmitting and receiving elements at a predetermined scanning pitch, defects in the surface layer of the round bar are detected at an angle; The method according to claim 1 is characterized in that it is a composite flaw detection in which the entire cross section is detected with one probe by repeating the following steps in a predetermined sequence: Ultrasonic flaw detection method for round bars.