JPH01119759A - Ultrasonic flaw detecting apparatus - Google Patents

Abstract

PURPOSE:To obtain an ultrasonic flaw detecting apparatus enabling the rapid and highly precise detection of a defect part, by providing a head member for a support shaft which is inserted between a body to be inspected and another body to be inspected. CONSTITUTION:A head member 4 is provided for a support shaft 2 inserted between a body w to be inspected and another body W to be inspected, and an axle 5a of a wheel 5 is fitted pivotally to one end part of this member 4 so that it is parallel to the support shaft 2, while an electromagnet 7 for a wheel is provided in a part of the member 4 on the opposite side to said wheel 5. An axle 8a of another wheel 8 is fitted pivotally to an output shaft 7a of said electromagnet 7 so that it it parallel to the support shaft 2, and an electromagnet 10 for a probe is provided in the middle of the member 4, while an array probe 13 is provided on an output shaft 10a of this electromagnet 10 so that it contacts with a part of the body W to be inspected. Then, this probe 13 is made to contact with the body W in conformity with the shape thereof, a defect signal and a shape signal are made discernible from a reflection echo (data) from the probe 13, and thereby the precision in inspection by ultrasonic flaw detection is improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention is an object of the present invention, which uses ultrasonic testing to detect defects caused by cracks in an object to be inspected, such as a rotor blade implant in a turbine rotor. This article relates to an ultrasonic flaw detection device for inspection.

(Prior Art) In general, the turbine blades of a turbine rotor in a steam turbine are embedded in a rotor disc one by one, and these turbine blades rotate continuously at high speed for a long period of time. Above, high stress due to centrifugal force acts on the implanted portion of the turbine blade implanted in the rotor disk during rotation.

In particular, in nuclear power plants, there is a risk of stress corrosion cracking (Scc) occurring because the steam is in a humid region.
During periodic inspections of turbines, it is desired to accurately inspect the implanted portion for the presence or absence of defects such as cracks.

Ultrasonic flaw detection means has been adopted as a means for inspecting the inset portion of this type of turbine blade, which has already been proposed. That is, this ultrasonic flaw detection means is constructed as shown in FIGS. 7 to 9.

7 to 9, the implanted part at of the turbine blade a as the object to be inspected is implanted in the engagement part b1 of the rotor disk, and a part of the turbine blade a has a fixed Each bevel probe C1°C2, C3 of the angle flaw detection element is attached, and each of these bevel flaw detectors C, CC is formed in the implanted part a1. ．． d2. Ultrasonic waves are applied to each locking portion d1.d3. d2. Defects such as cracks in part of d3 e1. e2. e3, this defective part e1. e2
．． The reflected echo from e3 is now visible.

That is, each of the above-mentioned locking portions d1. d2. For d3, each tilted probe c, ,c, , with a different refraction angle.

C3 is attached at an arbitrary position, and each of the tilted probes C,,C
2. The defective part e1. e2. ea is exposed.

The above-mentioned ultrasonic flaw detection means includes each inclined probe cl.

In order to determine C2, C3 and their scanning positions, the optimum incident angle is determined in advance based on the design drawing depicting the implanted part a1, and this
* It is difficult to quickly set the conditions for C2 and Ca, and each locking portion d1. of the implanted portion a1. d2. For the d3 inspection, it is necessary to install at least three different types of probes (probe elements) C1+ C2+ Ca at different scanning positions, which makes it impossible to perform a quick inspection and also prevents defective echoes. At the same time, different shape echoes caused by the complicated shape of the implanted portion a1 appear on the screen of the image display unit, making it difficult to inspect with high precision.

On the other hand, another ultrasonic flaw detection device (Japanese Unexamined Patent Publication No. 61-84221) shown in FIGS. When they come into contact, an ultrasonic wave is emitted and the defective part e t is detected by the reflected echo of the ultrasonic wave.
, e 2 , and e a are detected.

That is, the array probe C has a plurality of micro ultrasonic transducers arranged in parallel, and this array probe C excites other adjacent ultrasonic transducers at different times. When an ultrasonic wave is generated, the interference of the generated ultrasonic waves with a phase difference creates an ultrasonic beam, and the ultrasonic beam is transmitted from several stages of micro ultrasonic transducers. By controlling the phase of the wave transmission timing, the ultrasonic directivity can be strengthened in the desired h direction.

That is, the ultrasonic flaw detection device using the array probe C described above is capable of successively changing the transmission direction of ultrasonic waves by changing the control conditions of the array probe C (sector (also called scanning). the result,
- Each probe can function as a probe with several types of refraction angles, and by using the array probe C, each locking part d of the implanted part a can be used. ,,d2
゜■ It is possible to simultaneously detect the presence or absence of the defect d3 from the same position.

Therefore, in the ultrasonic flaw detection apparatus using the array probe C shown in FIG. 8, a signal is transmitted from the signal controller f at a predetermined timing, and this signal is applied to the multi-channel pulser g. Then, this multi-channel pulser g generates a high-voltage pulse for ultrasonic driving, and sends this high-voltage pulse to each corresponding vibrating element, giving the necessary delay amount for each vibrating element position according to the beam direction. It will be done. As a result, each vibrator is excited at a timing corresponding to its delay amount, and is sent to the object a to be inspected as a directional ultrasonic beam.

On the other hand, the reflected wave (reflected echo) from the inspected object a is
The ultrasonic wave is received by each vibrating element, and each vibrating element generates an electric signal corresponding to the intensity of the received ultrasonic wave.

Then, each of these electrical signals is sent to a multi-channel receiver h, where each signal is subjected to signal amplification and detection processing, and then sent to a high-speed A/D converter group i.

Then, after each is A/D converted and converted into digital data, this is added and synthesized with a delay corresponding to the transmission time in a digital adder j, and then this is sent to a signal processor l. (The stone is processed into image data corresponding to the scanning direction during ultrasonic scanning, converted into a video signal, and displayed as an image on the CRT display g.

On the other hand, the scanning direction of the ultrasonic beam is sequentially controlled by the delay time so as to perform sector scanning under the control of computer n1, and thus the ultrasonic beam from the array probe C performs sector scanning. will be done.

In this way, the image shown in FIG. 9 can be obtained using the electronic scanning electronic ultrasonic flaw detector and array probe C described above.
As shown in FIG. 9, an example of a B scope image obtained by applying the B scope image to the implanted part a1 of the inspected object a is shown, and n, nn, ol, 02 in FIG. 9 above are shown. ,03
are the respective defective parts e, , e2 . shown in FIG. e3 and each engaging portion d1. d2. d3, and by observing this B-scope display, it is possible to confirm whether the defective part is white or not.

(Problems to be Solved by the Invention) However, the above-mentioned ultrasonic flaw detection means cannot
When applied to a complex shape such as the implanted part a1, a simple scope display as shown in FIG.
Not only is it difficult to distinguish between shape echoes and defective echoes, but when ultrasonic waves are incident on the steel material of object a to be inspected from the acrylic shell C4 of the array type probe C, the refraction of the ultrasonic beam is As a result, the appearance of the ultrasonic beam does not converge to a single point, and as shown in Figure 9, the scope image requires skill to judge the defect position visually. There are drawbacks such as the risk of falling.

On the other hand, when the above defect position detection is performed automatically,
By scanning the array probe a and causing a positional shift, the reflected echoes detected by each flaw detection line (ultrasonic beams at different angles in sector scan mode) change, and these reflected echoes become "defects". It is extremely difficult to distinguish between "echoes" and "shape echoes," and it requires a lot of processing time. Furthermore, there are drawbacks such as a decrease in inspection accuracy. On the other hand, when detecting and evaluating defects that occur in the rotor blade implantation part of a turbine rotor, if a conventional fixed-angle probe C1°C21C3 is used, the refraction angle differs depending on the position of the defect. probes are required, and moreover, a lot of inspection time is consumed. Furthermore, since the shape of the implanted portion a1 is complex, it is difficult to distinguish between a "defect echo" and a "shape echo", and skill is required to make the determination, resulting in a significant drop in inspection accuracy.

Moreover, the ultrasonic flaw detection means using the above array contactor C is as follows:
Regardless of the location of the defect, it is sufficient to use one probe C, but from the B scope image displayed by this,
As mentioned above, it is difficult to distinguish between defect echoes and shape echoes, and stable and highly accurate ultrasonic flaw detection is difficult.

The present invention has been made in view of the above-mentioned circumstances, and provides a rapid and highly accurate ultrasonic flaw detection device for detecting defects occurring in the implanted part of a turbine rotor blade as an object to be inspected. The purpose is to provide.

[Structure of the invention]

(Means for solving the problems and their effects) The present invention includes:
A head member is provided on a support shaft inserted between an object to be inspected and another object to be inspected, and a wheel axle is pivoted at one end of this head portion +4 in parallel to the above-mentioned support shaft, and the opposite side of this wheel is An electromagnet for 11 wheels is provided on the head member on the side, and the width axis of the other small wheels is pivoted to the output shaft of the electromagnet for wheels parallel to the support shaft, and a probe is placed in the middle of the head member. 7 [i] A magnet is provided, an array probe is provided on the output shaft of this probe electromagnet so as to be in contact with a part of the object to be inspected, and the array probe and this array probe are covered. Identify the defect signal and the shape t= from the reflected echo (data) from the array probe by making contact with it in accordance with the shape of the inspection object (for example, the curved surface of the rotor blade implantation part). In this way, the inspection accuracy by ultrasonic flaw detection is improved.

(Example) Hereinafter, the present invention will be described with reference to an illustrated embodiment.

In FIGS. 1 and 2, reference numeral 1 indicates a support rod,
In the middle 1a of this support rod 1, a pair of support shafts 2 are horizontally arranged side by side and urged toward the support rod 1 by a spring 3, and on this support shaft 2, a head member 4 is mounted. For example, it is fitted so as to be inserted between an object W to be inspected by a rotor blade and another object W to be inspected. Also, one end portion 4 of this head portion 4
On a, an axle 5a of a wheel 5 is rotatably mounted on a pin shaft 6 so as to be parallel to the support shaft 4, and the wheel 5 is in contact with the object W to be inspected. It has become. Further, a wheel electromagnet (solenoid) 7 is provided in a part of the head member 4 located on the opposite side of the wheel 5, and the output shaft 7a of this wheel electromagnet 7 is connected to the other wheel 8. The center shaft 8a is pivoted by a pin shaft 9 so as to be parallel to the support shaft 4 and to be rotatable.

Therefore, when this wheel electromagnet 7 is excited, the output shaft 7a of this wheel electromagnet 7 brings the other wheel 8 into contact with a part of the other object W to be inspected, so that the head portion vI4 relatively is temporarily fixed.

On the other hand, a pair of probe electromagnets (solenoids) 10 are installed in the middle 4b of the head shrine 4, and a bracket 11 is attached to each output shaft 10a of both probe electromagnets 1o. are provided through each coil spring 12 so as not to be pulled out outward. Furthermore, this bracket 11
An array probe 13 having a plurality of ultrasonic probe elements built into a shoe is rotatably mounted around a bottle 14, and this array probe 13 is shown in FIG. It is connected to a multi-channel pulser 15 and a multi-channel receiver 16 through lead wires.

On the other hand, a marker probe (pen part) is attached to a part of the spindle 2.
A recording device (marker) 17 equipped with a marker probe 17a is vertically installed so as to be vertically movable by a marker electromagnet 18, and this recording device 17 has a marker probe pressure Ri! shown in FIG.
It is connected to a computer 20 via an I controller 19 .

Hereinafter, the effects of the present invention will be explained.

As shown in FIGS. 1 and 2, the ultrasonic flaw detection apparatus of the present invention is installed between an object W to be inspected and another object W to be inspected. That is, when the wheel electromagnet 7 of the head member 4 is excited, the output M7a of this wheel electromagnet 7 causes the other wheel 8 to come into contact with a part of the other object W to be inspected, thereby relatively causing the head member 4 is temporarily fixed, and on the other hand, the pair of probe electromagnets 10 are also excited. Then, each output shaft 10a of both probe electromagnets 10 is pushed outward against the elasticity of each coil spring 12.
The array probe 13 of the bracket 11 provided in the test object W comes into contact with the curved surface Wa of the object W to be inspected.

In this way, the array probe 13 can oscillate ultrasonic beams to each of the engaging portions d1, d, d3 of the object W to be inspected.

That is, in FIG. 3, when the array probe 13 emits a signal at a predetermined timing by the signal controller 21, this signal is transmitted to the multi-channel pulser 15 by oscillating a high-voltage pulse, which is transmitted from the array probe 13. The ultrasonic beam is applied to each of the above-mentioned engaging portions d1, d2. It is oscillated to d3. Then,
A reflected wave (reflected echo) of this ultrasonic beam is received by the array probe 13 and then transmitted to the multichannel receiver 16. Then, signal amplification, inspection processing, etc. are performed at the knee, and this is converted into A/D by the high-speed A/D converter group 22.
After conversion, it is sent to the digital adder 23.

Next, the peak detector 24 detects the peaks of the reflected echoes in each flaw detection line (ultrasonic beams at different angles in the sector scan mode) from the data of reflected echoes caused by the ultrasonic waves from the array probe 13. Ru.

On the other hand, in FIG. 3, the blade shape data memory 25 stores the shape data of the blade implanted part to be inspected, and the arithmetic unit 26 connected thereto calculates the result of the peak detector 24. The data of the peak value of the signal, the beam path data, and the shape data of the blade implanted part are superimposed to determine which part of the shape or defective part of the blade implanted part each signal corresponds to. to decide. A part of the result is sent to the computer 20 to finely adjust the angle of the flaw detection line, and when a defect echo is detected, the computer 20 is sent to the recording device 17.
or when the continuously detected shape echo is not detected or the shape echo becomes small, the pressing of the array probe 13 is controlled by pressure, etc. .

On the other hand, the signal processor 27 connected to the computer 20 and the arithmetic unit 26 includes the digital adder 23 and the arithmetic unit 2.
The blade shape is superimposed on the defect position and shape signals from the data in the blade shape data memory 25 and the image is displayed on the CRT 28 as a visual image output, or the data is recorded on a permanent recording medium. Data can be stored in the device 29.

Next, FIGS. 4 to 6 are flowcharts showing the flaw detection operation when the ultrasonic flaw detection apparatus according to the present invention is applied to a blade implanted part, and the test object W is shown in a wedge-shaped manner.

That is, in FIG. 4, the present invention is installed in a state where the rotor blades are stationary. That is, as described above, the array probe 13 and the wheel 5 are pressed together. Next, in (2), a reference echo is selected from among the shape echoes obtained in that state.

Therefore, two or more reference echoes are required, for example, the ultrasound beam 30a in FIG.

30b and 30c are respective reflected echoes 31a and 3 of the blade implantation part.
1b and 31c, and in (2), the refraction angle of the flaw detection line from which the reference echo is obtained is slightly changed, and the flaw detection line with the refraction angle at which the echo is the largest is set as the maximum reference line. Next, in step 2, the incident point 13a of the ultrasonic beam is calculated from the beam path of the echo obtained at the set maximum reference echo line. At this time, since the blade shape data memory 25 of the present invention stores the shape of the blade implanted part to be flaw-detected as described above, the above-mentioned incident point 13g
It is possible to easily calculate the position of the acrylic material, the angle of incidence on the blade implantation part with respect to the refraction angle within the shoe made of the acrylic material, and the optimum angle of incidence on the defective part. Further, as shown in FIG. 5, there is a position 32a where defects (cracks) are likely to occur in the blade implantation part.

32b and 32c can be set by calculating the refraction angle of the flaw detection line with respect to the defective part using .

Next, in step (2), a line for performing a coupling check during flaw detection is set. The optimal line setting for the coupling check is to set one or more lines, and this can be done by using the reference echo line as the coupling check line, or by setting a new line for other parts. It may also be a setting. Next, in (2), the supply of couplant is started at the same time as the turbine rotor is rotated, and thereby the flaw detection inspection of the cross-section inspection body W is started.

Next, the flaw detection inspection is performed according to the flowchart of FIG. 4 by checking whether the detection is completed successfully, checking whether the coupling echo is white, and checking whether the defect echo is white.

In addition, to check whether there is a coupling echo, when the echo of any of the coupling echo lines disappears, the operation of finely adjusting the pressure of the array probe 13 is performed again. After the check, a warning or stop signal is issued, or a warning is issued directly without changing the pressure of the array probe 13. especially,
To confirm the presence or absence of a defect echo, when a defect echo is detected on any of the flaw detection lines for the defective part, after finely adjusting the refraction angle of the flaw detection line and outputting a marker, the recording device 17 performs the following steps. Record the maximum value and appearance range (circumferential direction and refraction angle range) of the defect echo.

In this way, the blade implanted part as the upper limb test object W is sequentially inspected for flaws by the ultrasonic beam of the array probe 13 according to the present invention.

FIG. 6 shows an example of the flaw detection result output by the signal processor 27, which is output by the arithmetic unit 26 to the ultrasonic beam incident point 1.3, a, defect position W, each shape echo W2, etc. The image shows the result of superimposing the coordinate data and the input signal to the blade shape data memory 25.

In this way, as shown in FIGS. 1 and 2, the present invention can be installed between an object W to be inspected and another object W to be inspected, and by rotating the rotor once, the blade can be planted. Defect echoes such as cracks in grooves can be inspected quickly and with high precision.

〔Effect of the invention〕

As described above, according to the present invention, the head member 4 is provided on the support shaft 2 inserted between the inspected object W and another inspected object W, and the wheel 5 is attached to one end of the head member 4. An axle 5a is pivotally mounted parallel to the support shaft 2, a wheel electromagnet 7 is provided on the head member 4 on the opposite side of the wheel 5, and an output shaft 7a of the t-width electromagnet 7 is connected to the other wheel 8. The axle 8a is connected to the support shaft 2
Parallel to [4], a probe electromagnet 10 is provided in the middle of the head member 4, and the output shaft 1 of this probe electromagnet 10 is
Since the array probe 13 is provided at 0a so as to come into contact with a part of the object W to be inspected, not only is the handling operation easy, but also the defective part of the object W to be inspected can be detected accurately. In addition to being able to inspect with high precision, for example, even for objects with complex shapes such as the blades of turbine rotors, shape echoes and defective echoes can be accurately distinguished using an effective ultrasonic beam. It has excellent effects such as being able to identify the location of defects.

[Brief explanation of the drawing]

FIG. 1 is a front view of the ultrasonic flaw detection device of the present invention, FIG. 2 is a sectional view taken along the chain line A-A in FIG. 1, FIG. 3 is a block diagram of the present invention, and FIG. is a flowchart of the present invention, FIGS. 5 and 6 are diagrams for explaining the present invention in detail, FIG. 7 is a line diagram of an already proposed ultrasonic flaw detection device, and FIG. , the same block diagram as above, and FIG. 9 are diagrams for explaining the operation of the conventional example. 2... Support shaft, 4... Head member, 5... Wheel, 7
...+jj heavy-duty electromagnet for wheels...wheel, 10...electromagnet for probe, 13...array probe. Figure 2 Figure 3

Claims (1)

[Claims] 1. A head member is provided on a support shaft inserted between an object to be inspected and another object to be inspected, and a wheel axle is attached to one end of the head member parallel to the support shaft. A wheel electromagnet is provided in the head member on the opposite side of the wheel, and the axle of another wheel is pivotally connected to the output shaft of the wheel electromagnet parallel to the support shaft. 1. An ultrasonic flaw detection device characterized in that an electromagnet for a probe is provided in the electromagnet for the probe, and an array probe is provided on the output shaft of the electromagnet for the probe so as to come into contact with a part of the object to be inspected. 2. The ultrasonic flaw detection device according to claim 1, characterized in that a recording device is provided in the head member.