JPH0429411Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is applicable to the outer periphery and/or The present invention relates to a rotary flaw detection device that detects internal defects by electromagnetic induction (eddy current) flaw detection, leakage magnetic flux flaw detection, and/or ultrasonic flaw detection. Conventionally, in order to detect defects on the surface of a material to be inspected having a circular cross section, the material to be inspected is transported in the axial direction and a sensor is rotated at high speed along the outer periphery of the material to be inspected. Flaws are detected using a spiral scanning trajectory around the outer circumference of the test material. At this time, the smaller the lift-off (distance) change between the inspected material and the sensor, the more reproducible and stable defect detection ability can be obtained, and the smaller the absolute value of lift-off, the more sensitive it is to detect minute defects. It has been known. However, not only does the material to be inspected have a bend or a difference in diameter, but also mechanical vibrations are applied during transportation, which inevitably causes changes in the lift-off between the material to be inspected and the sensor. Therefore, in conventional flaw detection equipment, in order to restrict the passage center position of the inspected material as much as possible and to suppress mechanical vibrations, inlet guide sleeves are installed immediately before and after the rotating sensor in the traveling direction of the inspected material. In addition to providing an exit guide sleeve, the hole diameter value of the sleeve is very closely approximated to the outer diameter of the material to be inspected to greatly limit the amount of vibration amplitude of the material to be inspected, and the rotation sensor is made non-contact to reduce the amount of lift-off change. We are trying to reduce the
Efforts were made to keep the lift-off value constant by using a contact shoe or mechanical roll on the sensitive part of the rotating sensor.

An example of such a conventional rotary flaw detection device will be described with reference to FIGS. 8 and 9 of the accompanying drawings. FIG. 8 is a schematic cross-sectional view of a rotary probe flaw detection mechanism of a conventional rotary electromagnetic flaw detection apparatus, and FIG. 9 is a schematic diagram of a rotary disk portion in front of the rotary probe flaw detection mechanism of FIG. 8. This conventional rotary probe flaw detection mechanism 100 includes a rotating disk 104 fixed to a base plate 101 and supported by bearings 102 and 103.
It is equipped with This rotating disk 104 is rotated by applying a rotational force to a rotational drive pulley 105 from the outside via a V-belt or a timing belt (not shown). Also, rotating disk 1
04 is provided with a signal transmission slip ring 106, and the external fixed frame 108 is provided with a signal transmission brush 107, and these signal transmission slip ring 106 and signal transmission brush 10
Electric power and electrical signals can be exchanged through rotating contact with 7. The rotating disk 104 is equipped with an exciter 109 for generating leakage magnetic flux in the defective portion of the inspected material, and a sensor 110 for detecting defects (for example, a probe coil or an electromagnetic sensitive element such as a Hall element). There is. Exciter 1
09 is an excitation coil 109A and an excitation magnetic pole 109
It is composed of B. Power is supplied to the exciter 109 and signals are exchanged with the sensor 110 via the signal transmission slip ring 106 and the signal transmission brush 107, as described above.

These rotating disks 104, exciter 109,
The relationship with the sensor 110 is clearly shown in the front view of FIG. 9, and will be described below with reference to FIG. The inspected material 10 is made to travel straight in a direction perpendicular to the paper plane of FIG. 9, and the rotating disk 104 is rotated clockwise or counterclockwise. Two exciters 109 are disposed on the rotating disk 104 so as to surround the material 10 to be inspected, and each excitation magnetic pole 109B is arranged close to the outer peripheral surface of the material 10 to be inspected. These exciting magnetic poles 109B are C
An annular or U-shaped body that is made of materials for forming magnetic circuits, such as magnetic yoke for DC leakage magnetic flux testing, magnetic steel plate laminates for AC leakage magnetic flux testing, and electromagnetic induction (eddy current). ) For flaw detection, it is made of a suitable material depending on the frequency of the applied excitation magnetic flux, such as a laminate of electromagnetic steel sheets or a ferrite core. In the latter type of electromagnetic induction flaw detection,
Techniques such as the electromagnetic induction detection device disclosed in Japanese Patent Publication No. 11493 and the electromagnetic induction detection device using orthogonal crossing magnetic fields disclosed in Japanese Patent Publication No. 15020/1980 are applied.
Further, the excitation magnetic pole 109B includes an excitation coil 109.
A is arranged in a plurality of windings, and each exciter 10
The plurality of excitation coils 109A wound around 9 are
They are connected in series or in parallel so that the magnetic flux leaking to the outside from the open end of the excitation magnetic pole 109B strengthens each other. As described above, the open ends of the excitation magnetic poles 109B are disposed to face the circumferential surface of the material to be inspected 10, with a gap of several mm between them, and the material to be inspected 10 is arranged in a direction perpendicular to the paper plane of FIG. This is to prevent mechanical damage to the excitation magnetic pole due to bending, roundness, etc. of the inspected material when it is transported to the inspection site.

The exciter 109 is coupled to a size adjustment mechanism 111, and the size adjustment mechanism 111 is provided with a size adjustment knob 111A. Exciter 1
09 can be moved in the direction of arrow A by rotating and adjusting the size adjustment knob 111A. This size adjustment mechanism 111
When the outer diameter of the test piece is changed, that is, the present mechanism can be used for various materials to be inspected having different outer diameters. Size adjustment mechanism 111
A sensor support rod 112 is mechanically coupled to the
A pivot 113 is attached to the tip of this sensor support rod 112.
A movable arm 114 is provided so as to be able to rotate around this pivot 113. An exciter 1 is attached to one end of this movable arm 114.
A sensor 110 is coupled and fixed so as to be located in the centripetal direction of the inspected material 10 from the open end of the inspection target 10 . A balance weight 115 is attached to the other end of the movable arm 114. In this case, when the rotating disk 104 rotates, for example, clockwise, the sensor 110 and the balance weight 115 are adjusted so that the balance weight 115 is appropriately balanced.
15's weight has been adjusted. And sensor 1
10 and the circumferential surface of the material to be inspected 10 are brought into mechanical profiling contact using a contact shoe or the like.

On the other hand, in the conventional method, surface flaws on the test material are detected by electromagnetic flaw detection as described above, and flaws inside the test material are detected by ultrasonic flaw detection. were performed using separate equipment. Such a conventional example will be briefly explained with reference to the schematic diagrams of FIGS. 10 and 11.

FIG. 10 is a schematic plan layout of the conventional example, and FIG. 11 is a schematic side view thereof. As shown in FIGS. 10 and 11, in this conventional apparatus, the material to be inspected 300 is placed on a V-shaped roller conveyor
1,302,303A,303B,304A,3
04B, 305, 306, etc., it is transported in the direction of the arrow through an electromagnetic flaw detection stand 310 and an ultrasonic flaw detection stand 340, which are installed separately. The tip of the material to be inspected 300 is the roller 303A,
When the position 303B is reached, the fluid operating cylinder 321 in the pinch roll stand 320 is actuated to lower the pinch rolls 322A and 322B, thereby transporting the material to be inspected 300 in the direction of the arrow while pinching it. And these pinch rolls 322A, 3
On the exit side of 22B, electromagnetic flaw detection stand 31
Electromagnetic flaw detection is performed at 0, and flaws on the outer surface of the material to be inspected 300 are mainly detected. next,
The tip of the material to be inspected 300 is on the pinch roll stand 3
When the inspected material 300 reaches the rollers 304A, 304B below it, the pinch rolls 332A, 332B are lowered to pinch the inspected material 300 and further convey it to the left in the drawing. These pinch rolls 332
Ultrasonic flaw detection stand 3 on the exit side of A, 332B
40, ultrasonic flaw detection is performed, and flaws inside the inspected material 300 are mainly detected.

Problems to be Solved by the Invention In the conventional rotary sensor flaw detection mechanism as described above, the sensor and the circumferential surface of the material to be inspected are not in mechanical contact. The sensor 110 may temporarily jump due to irregular or unexpected mechanical vibrations in the vertical or horizontal direction of the material to be inspected, and the vibration may generate a false defect signal, or the sensor 110 may cause the material to be inspected to jump. There was a problem that the flaw detection function deteriorated while separated from the target. Furthermore, since the sensor is constantly in contact with the surface of the material to be inspected, it is subject to wear, making it difficult to maintain a long service life of the sensor, and causing problems such as the need to replace the contact shoe. Moreover, in this industrial field, demands for improved flaw detection accuracy and throughput are increasing, and therefore, to improve flaw detection accuracy, lift-off changes must be further suppressed. In addition, in order to improve processing capacity, it is becoming necessary to increase the rotational speed of the sensor and increase the flaw detection scanning peripheral speed. However, with the conventional mechanism mentioned above, which uses contact shoes and tracing rolls,
Due to constant contact with the inspected material, there are problems such as scratches on the surface of the inspected material, heat generation due to friction, and generation of false defect signals due to mechanical vibration due to contact tracing, so the rotation speed of the sensor is There is a limit to increasing the flaw detection circumferential speed (flaw detection relative speed).

Furthermore, in the conventional apparatus described above with reference to FIGS. 10 and 11, the electromagnetic flaw detection stand 310
For example, when applying the AC leakage flux method or eddy current flaw detection method using a conventional rotation sensor, the accuracy of detecting flaws on the outer surface is evaluated by the flaw depth, which is 0.1 mm to 0.2 mm deep from the outer surface. On the other hand, the ultrasonic flaw detection stand 340
For example, when applying the angle angle flaw detection method using a conventional rotating probe, the accuracy of detecting flaws inside the inspected material is at a depth of 3 mm to 5 mm from the outer surface.
This is enough to detect flaws with a depth of 0.15 to 0.3 mm. In ultrasonic flaw detection, it is not possible to accurately detect flaws on the outer surface of the material to be inspected, that is, on the skin, due to theoretical limitations. The sensor is installed separately. In this way, by combining the strengths of electromagnetic flaw detection for external surface flaw detection and the strengths of ultrasonic flaw detection for internal or fleshy parts, it has been possible to detect flaws on the external surface and inside of a material to be inspected. Consideration has been given to detecting flaws with high precision.

However, as described above, with the configuration of the conventional electromagnetic flaw detector, it was not possible to detect flaws on the outer surface with a flaw depth of 0.1 mm or less. Also,
In the conventional configuration, electromagnetic flaw detection for detecting flaws on the outer surface of the inspected material and ultrasonic flaw detection for detecting flaws inside the inspected material are performed on completely separate stands. It's expensive, and
This required more equipment space, and the overall flaw detection time also increased. Furthermore, in conventional methods, electromagnetic flaw detection and ultrasonic flaw detection are performed at different stations and at different times, and are not performed at the same time. It has been difficult to perform signal processing such as increasing the ease of identification of processed flaw signals.

Therefore, the purpose of the present invention is to solve the problems of the conventional technology as described above, to be able to perform flaw detection with high accuracy without shortening the service life even at high speeds, and to be able to perform not only electromagnetic flaw detection but also ultrasonic flaw detection. It is an object of the present invention to provide a rotary flaw detection device that can be configured to perform simultaneous testing.

Means for Solving the Problems According to the present invention, there is provided a rotary disk that rotates around the central axis of a material to be inspected having a circular cross section, an electromagnetic flaw detection sensor attached to the rotary disk, and an ultrasonic flaw detection sensor. and a sensor consisting of a probe, and detects defects on the surface of the inspected material by rotating the sensor around the inspected material by rotating the rotary disk, The sensor is held so that the sensitive part of the sensor faces the surface of the material to be inspected, and water is jetted onto the facing surface of the material to be inspected, thereby at least the ultrasonic flaw detection probe and the object to be inspected. A sensor holder having an opening that allows the ejected water to be interposed between the opposing surface of the material, and mounting for attaching the sensor holder to the rotary disk in a manner that allows the sensor holder to float. a member, a water supply means for supplying water to the opening of the sensor holder, and a restraining force that resists the reaction force of the jetting force of the water and the rotational centrifugal force to the sensor holder so that the sensor is sensitive to the sensor. and restraining force applying means for holding the portion close to the surface of the inspected material.

Embodiments Next, embodiments of the present invention will be described in detail based on FIGS. 1 to 7 of the accompanying drawings.

FIG. 1 is a schematic cross-sectional view similar to FIG. 8 showing a rotary flaw detection device as an embodiment of the present invention, and FIG. 2 shows a rotating disk portion at the front of the rotary flaw detection device of FIG. FIG. 9 is a schematic diagram similar to FIG. 9; 1st
In Figures 8 and 2, the above-mentioned Figures 8 and 9
Parts that are similar to the conventional device shown in the figures are designated by the same reference numerals and will not be described again, and only the improvements made by the present invention will be described in detail below.

In the rotary flaw detection apparatus 200 according to this embodiment of the present invention, air passages 202 and 203 are formed in the rotary drum 201 provided on the left side of the rotary disk 104. Furthermore, on the left side of the external fixing frame 108,
A water passage forming body 204 is provided, and water passages 205 and 206 communicating with water passages 202 and 203, respectively, are formed in this water passage forming body 204. Water passage forming body 204 and rotating drum 201
There is a water seal 20 between the
7, 208 and 209 are provided. The water passages 202 and 203 and the water passages 205 and 206 constitute a water supply passage from the external fixed frame to the rotating disk 104.

FIG. 3 is a perspective view showing the detailed structure of the rotating drum 201. As clearly shown in FIG. 3, an annular groove 210 is formed in the rotating drum 201 at a position always facing the water passage 205. , an annular groove 211 is formed at a position always facing the water passage 206. The depth of the annular groove 210 is the same as that of the annular groove 21.
It is deeper than the depth of 1. The water passage 202 is
The water passage 203 is formed through the peripheral wall of the rotating drum 201 with one end opening 202A in the side wall of the annular groove 210 and an opening 202B at the right end of the rotating drum 201. An opening 203A is formed at the right end of the rotating drum 201, and an opening 203B is formed at the other end so that the opening 203B is passed through the peripheral wall of the rotating drum 201.

The opening 202B of the water passage 202 is connected to a flexible water hose 21 as shown in FIG.
The water passage 203
The opening 203B is connected to one end 211 of a flexible water supply hose 211 as clearly shown in FIG.
It is communicated with A.

The other ends 210B and 211B of the water flow hose 210 and the water flow hose 211 are connected to the sensor 21.
2 are connected to one end of an air passage (not shown) of a sensor holder 213 holding a sensor holder 213. The water passage of the sensor holder 213 is connected to the material to be inspected 1.
It has an opening at a position opposite to the surface of 0, and water can be spouted from there. These sensor holders 213 are attached to one end of a movable arm 114 movable around a pivot 113 and hold the sensing portion of the sensor 212 so as to face the surface of the material 10 to be inspected.

In this embodiment, the sensor 212 is configured by appropriately arranging a plurality of electromagnetic flaw detection sensors and a plurality of ultrasonic flaw detection probes along the conveyance direction of the inspected material. The test frequency at this time is 4KHz~
Frequencies were used in the range of 128 KHz, the latter in the range of 4-6 MHz. Water ejected from the opening of the sensor holder 213 is interposed between the ultrasonic flaw detection probe and the opposing surface of the material to be inspected. In addition, water hoses 210 and 21
A pivot lubrication waterway (not shown) extending from a part of the tightening part of the ends 210B and 211B of 1 to the pivot 113
is formed on the movable arm 114, and the pivot 113
Water is supplied to the movable bearing part to provide a lubricating effect. Furthermore, the sensor holder 21
3 and the periphery of the sensor holder 213 are provided with a waterproof and drip-proof structure, for example, resin coating (not shown).

A piston rod 214A of a shock absorber 214 is coupled to the other end of the movable arm 114 near a balance weight 115 provided there.
is fixed to the support rod 112.

Pressurized water is supplied to the water passages 205 and 206 from the outside, and the supplied pressurized water is transferred to the water passage 202.
and 203, through the water passages of the water hoses 210 and 211 and the sensor holder 213, and is ejected from an opening (not shown) of the sensor holder 213 facing the surface of the material 10 to be inspected. This jetting of water maintains a gap between the surface of the material to be inspected 10 and the sensitive part of the sensor 212. On the other hand, by adjusting the balance weight 115, the above-mentioned gap caused by the jetted water is kept as small as possible, and in order to flatten the transfer function of the movable arm 114, balance weight 115, etc., mechanical transient vibration is suppressed by operating the shock absorber 214. I'm trying to absorb it. In this embodiment, the shock absorber 2
No. 14 is a double-acting cylinder oil damper using high viscosity oil and an orifice (relief groove), but it is designed so that the mass of the moving parts around the sensor is small and mechanical resonance is outside the area of use. If so, anti-seismic rubber may be used instead.

The rotary flaw detection device 200 of this embodiment of the present invention is as follows:
Although the structure is as described above, in order to perform flaw detection with this device 200, the material to be inspected,
For example, a material to be inspected 10 having a finite length such as a steel pipe or a steel bar is rotated at a constant speed by a roller conveyor or the like through the center opening 104A of the rotating disk 104 (see FIG. 2).
It is transported through the inside. At this time, due to the rotational action of the plurality of sensors 212 (four in the above embodiment) consisting of the electromagnetic flaw detection sensor and the ultrasonic flaw detection probe as described above of the rotary flaw detection device 200, the inspection target material 10 is detected. The outer surface and interior are scanned with a spiral trajectory, and flaw detection is performed automatically.

Next, in order to evaluate the ability of the non-contact sensor according to the present invention to follow the surface of the inspected material, a distance sensor was embedded in the sensor holder, and the sensor holder was rotated to measure the temporal change in the output of the distance sensor. When I recorded the results, I obtained results as illustrated in FIG. In FIG. 5, Δ ₀ indicates the minimum gap between the opposing surface of the sensor holder and the bale surface of the material to be inspected, which is 1.0 mm in this example, and Δ ₁ is the maximum variation width of that gap. In this example, 0.3mm
It was hot.

On the other hand, in order to compare with this, the results of investigating the temporal change in the gap between the sensor facing surface and the surface of the inspected material when using conventional mechanical contact are shown in the fourth section.
An example is shown in the figure. In FIG. 4, Δ ₂ indicates the gap between the sensor facing surface and the surface of the material to be inspected, that is, the maximum change in lift-off, and in this example, it was 0.5 mm. The measurement results shown in Figures 4 and 5 are based on a sensor circumferential speed of 1.0 m/sec,
The measurement results shown in FIG. 5 were obtained at a water pressure of 2.0 Kg/cm ² .

FIG. 6 schematically shows a steel pipe as an example of the material to be inspected, and this steel pipe 10 has an outer diameter () of 50.8 mm,
The wall thickness (t) is 5 mm, and the outer surface has a through hole scratch 11 with a diameter of 1 mm, a notch scratch 12 with a depth of 0.1 mm, a width of 0.5 mm, and a length of 5 mm, a depth of 0.2 mm, a width of 0.5 mm, and a length of 5 mm. Notch scratch 13, depth 0.3 mm, width 0.5 mm, length 5 mm Notch scratch 14, depth 0.4 mm, width 0.5 mm, length 5 mm
It has 15 notches on the inner surface with a depth of
It has a notch 16 of 0.2 mm, width 0.5 mm, and length 5 mm.

When such a steel pipe 10 was flaw-detected using an example of the rotary flaw detection device of the present invention, the flaw detection record by the electromagnetic flaw detection sensor was as shown in Figure 7A, and the flaw detection record by the ultrasonic flaw detection probe was An example was shown in Figure 7B. In FIGS. 7A and 7B, the horizontal axis shows time and the vertical axis shows the amplitude of the flaw signal.
is for notch 12, and signal 13A is for notch 13.
In addition, a signal 14A is detected corresponding to the notch 14, a signal 15A is detected corresponding to the notch 15, and a signal 16A is detected corresponding to the notch 16.

Effects of the invention According to the rotary flaw detection device of the invention, the following effects can be obtained.

(1) As is clear from the comparison of the measurement results in Figures 4 and 5, with the device of the present invention, the amount of change in lift-off can be reduced to about half of that of the conventional one. Not only can changes in flaw detection sensitivity due to changes be suppressed, but also changes in S/N due to lift-off changes can be minimized to maintain high detection accuracy. In general, electronic circuit compensation for sensitivity due to lift-off changes is a common practice in the prior art, but it is difficult to compensate for the latter change in S/N due to lift-off changes using electronic circuits. The effect of reducing the absolute value of the amount of change in lift-off is significant.

(2) In this invention, since the fluid pressure of water is used to cover the lower surface of the flaw detection surface, the sensor part does not come into mechanical contact with the material to be inspected, so there is no wear and a long life. Furthermore, there is no risk of damaging the material to be inspected.

(3) Since water is used as the fluid in this invention, by using this water as a medium for ultrasonic flaw detection, electromagnetic flaw detection and ultrasonic flaw detection can be performed at the same place and at the same time. , therefore,
Correlation and comparison between flaw signals detected by electromagnetic flaw detection and flaw signals detected by ultrasonic flaw detection can be easily performed, and the identifiability of flaw signals can also be improved. Further, since electromagnetic flaw detection and ultrasonic flaw detection can be performed on one stand, the cost of the entire device can be reduced and the installation space can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a rotary flaw detection device as an embodiment of the present invention, FIG. FIG. 4 is a perspective view showing the detailed structure of the rotating drum of the rotary flaw detection device shown in FIG. FIG. 6 is a diagram schematically showing a steel pipe as an example of the material to be inspected, and FIG. 7B is a diagram showing an example of flaw detection recorded by the ultrasonic flaw detection probe of the present invention on the steel pipe shown in FIG. 6, and FIG. 8 is a schematic cross section of the rotary probe flaw detection mechanism of a conventional rotary flaw detection device Figure 9 is a schematic diagram of the rotating disk section in front of the rotary probe flaw detection mechanism shown in Figure 6, and Figure 10 is a schematic plan layout showing the configuration of a conventional device that performs electromagnetic flaw detection and ultrasonic flaw detection on the same line. 11 is a schematic side view of the apparatus configuration shown in FIG. 10. 101... Base plate, 102, 103... Bearing, 104... Rotating disk, 105... Rotation drive pulley, 106... Signal transmission slip ring,
107... Signal transmission brush, 108... External fixed frame, 109... Exciter, 109A... Exciting coil, 109B... Exciting magnetic pole, 111... Size adjustment mechanism, 111A... Size adjustment knob, 112
...Sensor support rod, 113...Pivot, 114...
Movable arm, 115...Balance weight, 20
0... Rotating flaw detection device, 201... Rotating drum, 2
02,203...Water passage, 204...Water passage forming body, 205,206...Water passage, 210,211
...Water flow hose, 212...Sensor, 213...
...sensor holder, 214...shock absorber.

Claims (1)

[Scope of claim for utility model registration] (1) A rotary disk that rotates around the central axis of a material to be inspected having a circular cross section, and an electromagnetic flaw detection sensor and an ultrasonic flaw detection probe attached to the rotary disk. A rotary flaw detection device comprising: a sensor consisting of a The sensor is held so that the sensitive part faces the surface of the material to be inspected, and water is jetted onto the facing surface of the material to be inspected, so that at least the ultrasonic flaw detection probe and the material to be inspected face each other. a sensor holder having an opening that allows the ejected water to be interposed between the sensor holder and the surface; a mounting member for attaching the sensor holder to the rotary disk in a manner that allows the sensor holder to float; a water supply means for supplying water to the opening of the sensor holder; and a restraining force for resisting the reaction force of the jetting force of the water and the rotational centrifugal force to the sensor holder, so that the sensing portion of the sensor 1. A rotary flaw detection device comprising a suppressing force applying means for holding a material close to the surface of the material to be inspected. (2) The mounting member includes a support rod having one end attached to the rotary disk, and a movable arm having an intermediate portion attached to the other end of the support rod so as to be pivotable, and the sensor holder is , attached to one end of the movable arm, and the water supply means includes a fluid passageway to the rotary disk, and a flexible pipe that fluidly connects the fluid passageway and the opening of the sensor holder. The rotary flaw detection apparatus according to claim 1, wherein the restraining force applying means is a balance weight attached to the other end of the movable arm. (3) The rotary flaw detection device according to claim (2), wherein the restraining force applying means includes a shock absorber for shock absorption associated with the other end of the movable arm.