JP2922508B1 - Automatic ultrasonic flaw detector - Google Patents

Abstract

The present invention is used in a steel line for inspecting the entire cross section of a test material such as a round bar, and particularly for accurately detecting the depth and the circumferential position of a defect existing immediately below a surface. It is an object of the present invention to provide an automatic ultrasonic flaw detector. SOLUTION: A pair of oblique probes arranged on both sides of a vertical probe, a transmission / reception control unit for controlling a transmission / reception unit of each probe, and a vertical probe of the oblique probe A sound absorbing material is provided on the side where the main beam of the probe passes, and the oblique plate on the side of the vertical probe facing the test material, around the area other than the area where the main beam of the vertical probe of the diagonal plate passes It is provided with a sound absorbing material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an automatic ultrasonic flaw detector for online inspection of flaws existing in a billet, a bar or the like having a columnar cross section in a steel line. .

[0002]

2. Description of the Related Art FIG. 5 (a) is an axially sectional view of a round bar showing a probe arrangement of a probe holder portion in a conventional automatic ultrasonic flaw detector, and FIG. 5 (b) is a probe holder. 5 (c) is a circumferential cross-sectional view of a first angle beam probe part of the probe holder part, and FIG. 5 (d) is a probe holder. FIG. 7 is a circumferential cross-sectional view of a second oblique probe section of the section. In the figure, 1 is a test material such as a round bar, 2 is a vertical probe that transmits and receives ultrasonic waves to and from the center of the test material 1, and 3 is an oblique direction in a direction opposite to the rotation direction B of the test material 1. A first angle beam probe for transmitting and receiving ultrasonic waves, 4 is a second angle beam probe for transmitting and receiving ultrasonic waves obliquely in the same direction as the rotation direction B of the test material 1, and 5 is the vertical probe. A probe holder for fixing the probe 2 and the angled probes 3 and 4 at predetermined positions;
And a shoe provided on the facing surface and abutting against the surface of the test material 1;
7 is a couplant made of water or the like, 8 is a defect existing substantially at the center of the test material 1, 9 is a defect existing near the surface of the test material 1,
10 is a flaw detection pattern obtained by the vertical probe 2, 11 is a flaw detection pattern obtained by the first angle beam probe 3, 12 is a flaw detection pattern obtained by the second angle beam probe 4, and GI is a vertical pattern. A gate for limiting an area to be detected by the probe 2, a gate GA1 for limiting an area to be detected by the first oblique probe 3, and a GA2 for an area to be detected by the second oblique probe 3. , TI is a transmission pulse of the vertical probe 2, SI is a surface echo from the surface of the test material 1 in the vertical probe 2, and FI is a defect echo from a defect 8 existing substantially at the center of the test material 1. , BI is the test material 1
, TA1 is the transmission pulse of the first oblique probe 2, SA1 is the surface echo from the surface of the test piece 1 at the first oblique probe, and TA2 is the second oblique. A transmission pulse of the angle probe, SA2 is a surface echo from the surface of the test piece 1 in the second oblique probe, FA is a defect echo from a defect 9 existing near the surface of the test piece 1, and A is An end non-detection area generated by the vertical probe 2, an end non-detection area generated by the first angle probe 3, and an end undetection area generated by the second angle probe. is there.

[0003] A conventional automatic ultrasonic flaw detector is configured as shown in FIG. 5 (a), and comprises a vertical probe 2, an oblique probe 3,
The vertical probe 2 and the first oblique probe 3 are so arranged that the respective incident points 4 are on the same line on the surface of the test material 1 in the axial direction.
And the second angled probe 4 are respectively fixed to the probe holder 5, and the shoe 6 provided on the surface of the probe holder 5 facing the test material 1 has a diameter of the test material 1. By exchanging accordingly, the position of the incident point of each of the probes 2, 3, and 4 does not significantly change. When the probe holder 5 performs the flaw detection test while moving in the direction of the arrow A on the surface of the test piece 1 under the arrangement conditions of the probes 2, 3, and 4 shown above, for example, When the probe holder 5 is brought into contact with the end of the test material 1 on the tip side of the material 1, the vertical probe 2 slightly has an end undetected flaw area A, and the first angle beam probe 3 has an end undetected area B wider than the end undetected area A, and the second oblique probe 4 has an end undetected area C wider than the end undetected area B. That is, the test material 1
The undetected area c in which the flaw cannot be detected over the entire cross section occurs on both the front end side and the rear end side of the test sample 1.
Further, since the vertical probe 2, the first oblique probe 3, and the second oblique probe 4 are arranged in the axial direction of the test material 1 and have large dimensions, the test material is large. A state in which the shoe 6 provided on the probe holder 5 cannot adhere to irregularities or bends on the surface in the axial direction often occurs, and the flaw detection result becomes unstable.

Further, the conventional automatic ultrasonic flaw detector is configured as described above, and the ultrasonic wave transmitted from the vertical probe 2 reaches the surface of the test material 1 via the couplant 7, A part of the ultrasonic wave is reflected by the vertical probe 2 and received as a surface echo SI, and the ultrasonic wave transmitted inside the test material 1 propagates toward the bottom surface of the test material 1, and a defect 8 exists on a path along the way. In this case, the reflected wave from the defect 8 is received by the vertical probe 2 as a defect echo FI, and the further advanced ultrasonic wave reaches the bottom surface of the test piece 1 and is received by the vertical probe 2 as a bottom surface echo BI. You. At this time, the detection range of the defect signal is determined by the setting of the gate GI.
The inside range excluding a dimension corresponding to about 10% of the diameter from the surface side is defined as the inspection range. On the other hand, bevel probe 3,
The ultrasonic wave transmitted from the probe 4 reaches the surface of the test material 1 via the couplant 7 and a part of the ultrasonic wave is reflected on the oblique probes 3 and 4 and received as surface echoes SA1 and SA2. The ultrasonic wave transmitted inside the material 1 propagates toward the side surface of the test material 1,
When the defect 9 is present on the way along the way, the reflected wave from the defect 9 is received by the second angle beam probe 4 as a defect echo FA. The gates GA1 and GA2 of the first angle beam probe 3 and the second angle beam probe 4 are set so that only the vicinity of the surface outside the inspection range of the vertical probe 2 becomes the inspection range. . Further, the first angle beam probe 3 and the second angle beam probe 4 are arranged so that the directions of incidence of ultrasonic waves to the test material 1 are different from each other. Defect 9 can be reliably detected by one of the oblique probes 3 and 4 even if the reflection characteristics of the laser beam are biased. The vertical probe 2, the first oblique probe 3, and the second oblique probe 4 are arranged so as to be shifted from each other in the axial direction of the test sample 1. Since there is no interference, transmission and reception can be performed simultaneously.

[0005]

In the conventional automatic ultrasonic flaw detector, the existence positions of the defects 8 and 9 are roughly identified by using the defect echo FI received by the vertical probe 2 as the inside of the test material 1. Echoes FA received by the angle probes 3 and 4
Is only near the surface, and especially in the vicinity of the surface, it is necessary to know the depth of the defect at a depth of several mm below the surface, and to determine the quantitative dimensions and the position on the circumferential cross section.
However, there is a problem that the grinder in the next step cannot be efficiently maintained because the ultrasonic wave cannot be spread accurately.

Further, since the vertical probe 2 and the oblique probes 3 and 4 are arranged side by side in the axial direction of the test material 1, the length of the probe holder 5 becomes longer. There is a problem that it is difficult to stably maintain the posture of each of the probes 2, 3, and 4 with respect to unevenness and bending in the axial direction of the test material 1.

Further, since the vertical probe 2 and the oblique probes 3 and 4 are arranged side by side in the axial direction of the test material 1, the length of the probe holder 5 becomes longer. There is a problem that the end undetected area c at the front end and the rear end of the test material 1 does not become small.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and can accurately detect the depth of a defect existing near the surface of a test material and the position on a circumferential cross section. It is an object of the present invention to provide an automatic ultrasonic flaw detector that reduces the length of each probe, thereby reducing the stability of the posture of each probe and the undetected end area at the front and rear ends of the test sample 1.

[0009]

In the automatic ultrasonic flaw detector according to the present invention, the test piece is disposed at a position on the same circumferential cross section of the test piece having a water distance of not less than a quarter of the diameter of the test piece. A vertical probe, a first bevel probe and a second bevel probe on both sides of a main beam of the vertical probe, and a transmitting / receiving unit connected to the vertical probe, A transmission / reception unit connected to the first angle beam probe, a transmission / reception unit connected to the second angle beam probe, and a transmission / reception control unit for controlling the respective transmission / reception units are provided.

In addition, a sound absorbing material is provided on a surface of the vertical probe of the first angle beam probe and the second angle beam probe facing the main beam side.

Further, an oblique plate made of an acrylic material provided with a sound absorbing material is provided on the side of the vertical probe facing the surface of the test piece, in addition to the main beam passage area of the vertical probe.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 1 and 2 and Table 1 are diagrams and tables showing an automatic ultrasonic flaw detector according to Embodiment 1 of the present invention. FIG. 1 shows the arrangement of a probe holder and a probe and a transmission / reception control unit. FIG. FIG. 2A is a diagram showing transmission / reception timing of each probe and a flaw detection pattern. FIG. 2B is a diagram showing a two-probe method using a vertical probe and an oblique probe. Table 1 is a table showing the operation status of the transmission unit and the reception unit connected to each probe. In the figure, 1 to 12 are the same as those of the conventional apparatus, 13 is a vertical transmission unit for the vertical probe 2, 14 is a vertical reception unit for the vertical probe 2, and 15 is a first angle beam probe. A first bevel transmitting unit for 3; 16 a first bevel receiving unit for the first bevel probe 3; 17 a second bevel transmitting unit for the second bevel probe 4; Reference numeral 18 denotes a second oblique angle receiving unit for the second oblique angle probe 4, and 19 denotes each of the transmitting / receiving units 13 to 18.
, 20 is the main beam of the vertical probe 2, 21 is the first timing, 22 is the second timing, and 23 is between the vertical probe 2 and the first oblique probe 3. Figure 24 shows the flaw detection pattern by the two probe method,
Flaws detected by the two-probe method between the oblique probes 4 of FIG.
IA is a defect echo detected by the two-probe method, GIA
Reference numeral 1 denotes a gate for limiting a flaw detection range between the vertical probe 2 and the first oblique probe 3 by the two-probe method, and GIA2 denotes a gate between the vertical probe 2 and the second oblique probe 4. This is a gate that limits the flaw detection range by the two-probe method.

In the automatic ultrasonic flaw detector constructed as described above, the vertical probe 2 is mounted on the upper surface of the probe holder 5 in the same manner as the conventional apparatus, but the first angle beam probe is used. Since the probe 3 and the second oblique probe 4 are mounted on both sides of the probe holder 5 and in the same cross section as the vertical probe 2, the probe holder 5 is attached to the test piece 1. In the position where the probe has contacted, the end undetected area a of the end of the test material 1 generated on each of the probes 2, 3, and 4 is the same for any of the probes 2, 3, and 4, and on the tip side. However, it can be minimized at the rear end. However, as described above, the vertical probe 2 and the oblique probes 3, 4
When the probes 2, 3, and 4 are simultaneously transmitted and received in a state in which they are arranged in the same cross section, the ultrasonic waves transmitted from the vertical probe 2 are received by the oblique probes 3, 4 or conversely. In order to prevent the ultrasonic waves transmitted by the angled probes 3 and 4 from being received by the vertical probe 2 and to detect the defects 8 and 9 erroneously, the above-described erroneous detection is prevented. A transmission / reception control unit 19 is provided.

That is, as shown in Table 1 and FIG. 2A, at the first timing 21, the first oblique transmission unit 15 and the first oblique reception unit connected to the first oblique probe 3 are used. The second oblique angle transmitting section 17 and the second oblique angle receiving section 18 connected to the section 16 and the second oblique angle probe 4 are put into an operating state,
The vertical probe 2 is in a stopped state during the transmission and reception by the probe 4, and the ultrasonic waves transmitted from the oblique probes 3 and 4 transmit
The transmission and reception control unit 19 stops transmission and reception of the oblique probes 3 and 4 after a lapse of time required to reach the side surface of the oblique probes 3 and 4 and to receive the signals again. Output a signal. Next, at the second timing 22, the vertical transmission unit 13 and the vertical reception unit 14 connected to the vertical probe 2 are put into the operating state, and the first angle transmission unit connected to the first angle probe 3 is set. 1
5 and the second bevel transmitter 1 connected to the second bevel probe 4
The transmission / reception control unit 19 outputs a signal so that 7 is in a stopped state.

Further, the vertical probe 2 is provided with a distance of at least about one-fourth of the diameter of the test material 1 and the probe holder 5.
The space between the vertical probe 2 and the test material 1 is filled with a couplant 7 such as water. Since the velocity of the ultrasonic wave propagating through the couplant 7 such as water is about a quarter of that of the test material 1 (material: steel), the distance between the surfaces of the vertical probe 2 and the test material 1 is By providing a distance of about one-quarter or more of the diameter of the test material 1, a second surface echo SI2 from the surface of the test material 1 is generated behind the time when the bottom echo BI is generated, and the second test is performed. Does not occur in the gate GI. When the vertical probe 2 is in the transmission / reception state, the first bevel receiver 16 is in contact with the first bevel probe 3 and the second bevel receiver is connected to the second bevel probe 4. When a signal for bringing the unit 18 into the receiving state is output from the transmission / reception control unit, the vertical probe 2 and the first oblique probe 3 and the vertical probe 2 and the second oblique probe 4 The operating conditions of the two-probe method are respectively satisfied between them. The feature of the two-probe method is that the level and the duration of the surface echoes SIA1 and SIA2 can be greatly reduced.
The defect 9 can be detected from a distance of about mm. Also,
Since the first angle beam probe and the second angle beam probe have a gap of only a few mm between the surface of the test piece 1 and the defect 9
Can be received at a position where the reflected wave from the probe does not greatly diffuse, and the conditions that can be received by the above-described two-probe method are a little from the point directly below the vertical probe 2 to the incident point of each of the oblique probes 3 and 4. It is possible to accurately detect not only the depth of the defect 9 near the surface but also the circumferential position of the test material 1.

Embodiment 2 FIG. 3 is a sectional view of a probe and a probe holder of an automatic flaw detector according to a second embodiment of the present invention. In the figure, reference numerals 1 to 7 are the same as those in the related art. 25 is a side lobe emitted from the vertical probe 2,
26 is a rubber-like sound absorbing material.

The position where the oblique probes 3 and 4 are attached to the probe holder 5 according to the present invention is in the couplant 7 through which the ultrasonic beam of the vertical probe 2 passes, and the main position of the vertical probe 2 is Even if it is arranged outside the beam 20, it is possible to prevent a low level ultrasonic component such as the side lobe 25 from reaching the surfaces of the oblique probes 3, 4 arranged on both sides of the vertical probe 2. Can not. The reflected waves from the oblique probes 3 and 4 are reflected by the vertical probe 2
A sound absorbing material 26 made of a rubber-like elastic body for preventing ultrasonic waves from being reflected is provided on the surfaces of the oblique probes 3 and 4 because the noise sources are fixed to the transmission / reception conditions. It is provided. Therefore, even if the vertical probe is operated under this condition, the oblique probes 3 and 4 do not become a noise source and the S / N
High flaw detection conditions can be secured.

Embodiment 3 FIG. 4 is a sectional view of a probe and a probe holder of an automatic flaw detector according to a third embodiment of the present invention. In the figure, reference numerals 1 to 7 are the same as those in the related art. 27 is a diagonal plate made of acrylic, and 28 is a sound absorbing material provided on the diagonal plate.

In the arrangement of the vertical probe 2 and the oblique probes 3 and 4 according to the present invention, since the respective probes 2, 3 and 4 cannot be transmitted and received simultaneously as described above, the transmission repetition frequency is increased. There is a restriction that it cannot be done. Above all, in the vertical probe 2, the multiple reflection wave of the surface echo SI that appears to be reciprocated many times in the couplant 7 where the ultrasonic wave is less attenuated is the maximum constraint condition. An oblique plate 27 made of an acrylic resin for forcibly lowering the level is provided in a range where the main beam 20 of the vertical probe 2 passes. The ultrasonic wave passing through the diagonal plate 27 has an angle of about 45 ° with respect to the axis from which the ultrasonic wave is radiated to the test piece 1 under the condition that only the transverse wave passes without passing the longitudinal wave. A sound absorbing material 28 made of a rubber-like elastic body is provided at a portion other than the width of the vertical probe 2 other than the main beam 20 and fixed to the probe holder 5. Therefore, the side lobe 25 of the ultrasonic wave radiated from the vertical probe 2,
The main beam 20 is reflected from the surface of the test material 1 and
4 and returns to the vertical probe 2 again, thereby preventing interference echo.

[0020]

Since the present invention is configured as described above, it has the following effects.

The vertical probe, the first oblique probe, and the second oblique probe in the probe head are arranged in the same cross section of the test piece, and each probe is By including a transmission and reception control unit that controls the operation status of the connected transmission and reception unit, it is possible to reduce the end undetected areas at the front and rear ends of the test material,
Furthermore, by realizing the two-probe method between the vertical probe and the oblique probe, it is possible to accurately detect the depth and circumferential position of a defect existing immediately below the surface, and as a result, It is possible to efficiently perform grinder care for removing surface defects and defects existing immediately below the surface.

Further, since the sound absorbing material is provided on each surface of the first angle beam probe and the second angle beam probe facing the region where the main beam of the vertical probe passes, Reflected waves and the like of side lobes emitted from the probe do not become disturbing echoes, thereby enabling a flaw detection test with a high S / N ratio.

In addition, since an oblique plate is provided in a region where the ultrasonic beam of the vertical probe passes, and a sound absorbing material is provided outside a range where the main beam of the vertical probe of the oblique plate passes, By greatly reducing the number of multiple reflections of the surface echo on the surface of the test material obtained by the vertical probe and increasing the transmission repetition frequency, high-speed flaw detection can be performed and at the same time, side lobes other than the main beam are reduced. Since it can be absorbed by the sound absorbing material provided on the oblique plate, the S / N ratio can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an arrangement of a probe and a transmission / reception control unit of an automatic ultrasonic flaw detector according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing transmission / reception timings of each probe and a flaw detection pattern in the automatic ultrasonic flaw detector according to Embodiment 1 of the present invention;

FIG. 3 is a sectional view showing an automatic ultrasonic flaw detector according to Embodiment 2 of the present invention;

FIG. 4 is a sectional view showing an automatic ultrasonic flaw detector according to Embodiment 3 of the present invention.

FIG. 5 is a cross-sectional view showing a conventional automatic ultrasonic flaw detector.

[Table 1]

[Explanation of symbols]

1 test material, 2 vertical probe, 1st angle beam probe,
4 second oblique probe, 13 vertical transmitting section, 14 vertical receiving section, 15 first oblique transmitting section, 16 first oblique receiving section, 17 second oblique transmitting section, 18 second oblique receiving section Part 1
9 Transmission / reception control unit, 26 bevel probe sound absorbing material, 27 diagonal plate, 28 diagonal plate sound absorbing material.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshimi Fukutaka 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. Kawasaki Steel Corporation Mizushima Works (56) A) JP-A-1-195359 (JP, A) JP-A-61-44349 (JP, A) JP-A-61-54266 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) ) G01N 29/00-29/28

Claims (3)

(57) [Claims] 1. A test device comprising: a vertical probe for transmitting and receiving ultrasonic waves perpendicular to a center of a columnar test material; and an oblique probe for transmitting and receiving ultrasonic waves to the test material obliquely. In an automatic ultrasonic flaw detector that inspects the flaws existing inside the material online, one probe holder and the diameter of the material to be inspected from the surface of the material to be inspected on the extension line of the center of the material to be inspected. A vertical probe arranged on the upper surface of the probe holder at a position provided with a distance of not less than one-fourth of the length of the main beam of the vertical probe, and an axial position of the test material Is a pair of oblique probes arranged on both sides of the probe holder at the same position as the vertical probe and a gap of several mm from the surface of the test material; A vertical transmitting unit that drives the probe, a vertical receiving unit that amplifies and processes the received signal of the vertical probe, A first oblique transmission unit that drives each of the angle probes, a second oblique angle transmission unit, a first oblique angle reception unit that amplifies a reception signal of each of the pair of oblique angle probes, Transmission / reception control for controlling each of the two oblique reception units, the vertical transmission unit, the vertical reception unit, the first oblique transmission unit, the second oblique transmission unit, the first oblique reception unit, and the second oblique reception unit And an automatic ultrasonic flaw detector. 2. A sound absorbing material such as rubber having a high sound absorbing effect is provided on the exposed surface of the vertical probe facing the main beam on the inner surface side of the probe holder of the angle beam probe. The automatic ultrasonic flaw detector according to claim 1. 3. An oblique plate made of an acrylic material is provided between the vertical probe and the surface of the test material, and a sound absorbing material such as rubber is provided on both outer sides of the main beam passing range of the vertical probe of the oblique plate. The automatic ultrasonic flaw detector according to claim 1, wherein: