JPH10239287A - Turbine rotor blade built-in part supersonic flaw-detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a defective part without being restricted by the shape of a blade built-in part. SOLUTION: Supersonic waves from a probe 7 for detecting flaw are applied from the base part side surface side of a blade leg part 33a toward a boundary position 12 where a blade built-in parts are adjacent one another, are reflected by the end face of an adjacent saddle type part 32 and are directed toward a protrusion 32b for detecting the presence of a defective part 10. As compared with a conventional technique for applying ultrasonic waves from the base part side of the saddle type part 32a in a turbine rotor 30, reflecting the supersonic waves by the tip of the saddle type part 32a, and hence detecting a defective part, ultrasonic waves can be positively applied to the protrusion 32b without being affected by the geometrical shape and dimensions of the wheel base part side and the blade built-in part and hence the defective part 10 can be detected accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for irradiating an implanted portion of a blade implanted in a turbine rotor with ultrasonic waves and detecting a defect such as a crack generated in the implanted portion. The present invention relates to an ultrasonic flaw detector for a turbine rotor blade implantation part.

[0002]

2. Description of the Related Art FIG. 8 shows a turbine rotor 30 used in a general steam turbine. That is, as shown in FIG. 8, the turbine rotor 30 has a predetermined number of wheels 32 fixed at an intermediate position of a shaft 31, and blades 33 are implanted on the outer periphery of the wheel 32. In this case, on the outer peripheral portion of the wheel 32, as shown in an enlarged view, a projection 3 formed in a step shape and having a width gradually reduced toward the tip end.
The saddle-shaped portion 32a having the 2b is formed while the blade 33
Are formed with leg portions 33a, and hook grooves 33b formed in a shape corresponding to the saddle-shaped portions 32a are formed in the leg portions 33a, and the saddle-shaped portions 32 are formed in these hook grooves 33b.
By fitting and assembling “a”, the blade implant portion is formed.

[0003] Such a projection 32b at the tip of the saddle-shaped portion 32a.
, It is necessary to confirm its soundness because high stress acts on it, and therefore, ultrasonic inspection is applied. Particularly, in the saddle-shaped portion 32 in which a large number of blades 33 are implanted, an example in which a crack is generated in the projection 32b corresponding to the boundary position between the blade 33 and the hook groove 33b is reported.

A conventional ultrasonic flaw detector is disclosed in Japanese Unexamined Patent Publication No.
As shown in FIG. 9, the ultrasonic probe 34 is applied to the base side of the wheel saddle-shaped portion 32, and in this state, ultrasonic waves 35 are applied to the saddle-shaped portion 32a from the wheel base side. When radiated toward the tip, the ultrasonic waves 35 are reflected at the saddle-shaped portion distal ends, and the reflected ultrasonic waves 36 are directed to the projections 32b, thereby determining whether or not cracks are generated in the projections 32b. Crack occurrence is detected.

[0005]

By the way, in the conventional ultrasonic flaw detector described above, as shown in FIG. 9, ultrasonic waves 35 are irradiated from the base side of the saddle-shaped portion 32a of the turbine rotor wheel 32. The crack is detected by the reflection of the ultrasonic waves 35 at the tip of the saddle-shaped portion 32a. However, depending on the geometrical shape and dimensions of the wheel base and the saddle-shaped portion 32a on which the ultrasonic probe 34 is applied. In some cases, the ultrasonic beam may not reach a defect such as a crack.

[0006] For example, as shown in FIG.
The ultrasonic probe 34 is installed on the base side of the
In the conventional technique of reflecting the ultrasonic wave at the tip of a, the tip 33c of the blade leg 33a and the like may be located in the beam path of the ultrasound 35 emitted from the ultrasound probe 34. Since the ultrasonic wave 35 cannot be reflected at the saddle-shaped portion tip, there is a problem that the ultrasonic beam does not reach the defective portion and the device cannot be used.

Further, even if the ultrasonic wave 35 can be reflected at the tip of the saddle-shaped portion, the ultrasonic beam path may be long, so that not only the ultrasonic wave is attenuated but also the ultrasonic wave is As a result, noise is increased, and as a result, there is a problem that it is difficult to accurately detect a defective portion such as a crack.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is an object of the present invention to not only be irrelevant to the shapes of the wheel saddle portion and the blade legs when irradiating an ultrasonic beam, but also to reduce attenuation and noise. It is an object of the present invention to provide a turbine rotor blade implanted ultrasonic inspection device capable of reliably irradiating an ultrasonic wave to a desired position without generating the defect and accurately detecting a defective portion.

[0009]

According to the present invention, there is provided a blade plant comprising a plurality of saddle-shaped portions provided on an outer periphery of a turbine rotor along an axial direction and blades fitted and assembled to the saddle-shaped portions. In a flaw detector that irradiates ultrasonic waves to the insertion portion and detects a defect such as a crack existing in the projection of the saddle-shaped portion, the blade implantation portion to be inspected for the turbine rotor is impregnated with water, A water tank that fills a gap between a projection of the saddle-shaped portion and a leg of the blade in the implantation portion, and a gap between the projection of the saddle-shaped portion and the leg of the blade in the blade implantation portion is filled with water. When in the state, the ultrasonic wave is irradiated from the tip side surface of the saddle-shaped portion to be inspected to the boundary position between the blade-implanted portion to be inspected and the adjacent blade-implanted portion. The sound wave is reflected by the end face of the adjacent saddle-shaped portion, travels toward the projection of the saddle-shaped portion to be inspected, and is located on the projection. It is characterized in that it has a detection means for detecting the presence or absence of a defect to be.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In order to improve the sensitivity of ultrasonic waves, the ultrasonic flaw detector of this embodiment impregnates the blade implanted portion as an inspection target with water, and in this state, the saddle-shaped portion 32a of the blade implanted portion and the blade leg portion. When water is filled between the nozzles 33a, a defect 10 such as a crack is detected by irradiating the detection target with an ultrasonic wave. As shown schematically in FIG. A water tank 1 for immersing the implanted part, a scanning table 2 having a detection means, and a determination processing part (not shown) for determining the presence or absence of a defect 10 such as a crack based on detection of a detector are provided. It is configured.

The water tank 1 contains a turbine rotor 3 for inspection.
0 for impregnating the blade implant portion.
Is infiltrated between the projection 32b of the saddle-shaped portion 32a in the blade-implanted portion and the blade leg 33a by capillary action, so as to fill the gap 11 therebetween.

At the time of inspection, the scanning table 2
Rim 32d which is the base of the wheel 32 provided in
In the present example, the roller 2a has a magnet roller 2a that rolls on the rim 32d, and the roller 2a rolls and moves while adsorbing on the rim 32. .

As shown in FIG. 1, the scanning table 2 is provided with detecting means on a flaw detection head 4 mounted via an arm 3. That is, as shown in FIGS. 1 to 3, the detecting means includes a blade leg boundary detecting sensor 5 and a water immersion confirming probe 6.
And a flaw detection probe 7.

Here, as shown in FIGS. 2 (b), 2 (c) and 3, the blade leg boundary detecting sensor 5 detects the position of the defect 10 when inspecting the defect 10 such as a crack. The boundary position 12 between the adjacent blade implants, that is, the wheel saddle-shaped portion 32a of the blade implant to be inspected is set.
The boundary position 12 between the blade leg 33a fitted into the blade leg 33a and the blade leg 33a of the blade implantation part adjacent thereto is detected.

Specifically, the blade leg boundary detection sensor 5
4A, for example, as shown in FIG.
b, and a balance coil 52 disposed at a position distant from the detection coil 51.
And a measuring bridge 53 connected to each coil. When the blade leg boundary detecting sensor 5 moves to the boundary position 12 between the adjacent blade legs 33a during the inspection, the measuring bridge 53 And the bridge 53 outputs a signal voltage eo from the bridge 53 as shown in FIG. The signal voltage eo becomes maximum at the boundary position 12 and becomes a mountain-shaped waveform that decreases as the distance from the boundary position 12 increases. To be detected.

The probe 6 for confirming the water immersion improves the ultrasonic wave emitted from the probe 7 for flaw detection described later.
As shown in FIGS. 2 and 3, the ultrasonic wave 6a is applied to the gap 11 between the wheel saddle-shaped portion 32a to be detected and the blade leg 33a fitted to the portion to be detected. The irradiation determines whether or not the water in the water tank 1 is filled between the blade leg 33a and the projection 32b of the wheel saddle-shaped portion 32a. In this case, as shown in FIGS. 2 (a) and 2 (c), the probe 6
a, ultrasonic waves 6a are irradiated from a direction orthogonal to the projections 32b in which the defective portions 10 are expected to have occurred, so that the blade legs 33a and the hook portions 32b of the saddle-shaped portions 32a are filled with water. Is determined.

The probe 7 for flaw detection includes a wheel saddle-shaped portion 32a.
Is to detect whether or not a defect 10 such as a crack exists in the projection 32b. More specifically, as shown in FIG. 1, the probe for flaw detection 7 has the blade 33 and the wheel 32 to be inspected put in the water tank 7, and FIGS. As shown in the figure, the blade leg boundary detection sensor 5 detects the boundary position 12 between the blade leg 33a on the wheel saddle type portion 32a to be inspected and the blade leg 33a adjacent to the wheel saddle portion 32a. When it is detected that the gap 20 between the wheel saddle-shaped portion 32a to be inspected by the probe 6 and the blade leg 33a fitted thereto is filled with water, the blade leg 33a to be inspected. When the ultrasonic wave 7a is irradiated from the base side surface toward the boundary position 12, the ultrasonic wave 7a is reflected by the end face 13 of the adjacent blade leg at the boundary position 12, and the reflected ultrasonic wave 7b is reflected by the blade leg portion. 33a and By toward the projection 32b of 該鞍 type portion 18 through the mold unit 18, so as to detect whether a defect 10, such as cracks in the projections 32b are present.

In FIG. 2A, φ is the irradiation angle of the ultrasonic wave 7a when irradiated from the flaw detection probe 7 when viewed from above, and in FIG. This is the angle between the ultrasonic wave irradiation angle from the probe 7 and the reflected ultrasonic wave 7b.

The data detected by the water immersion confirmation probe 6 and the flaw detection probe 7 are taken into the ultrasonic flaw detector 8 and amplified, and the data is recorded and processed through the ultrasonic flaw detector 8. 9 to determine whether or not water is full and whether or not there is a defective portion 10 as described above, and also to determine the position of the boundary position 12 between the mutually adjacent blade legs 33b and the position of the defective portion 10. I am trying to do specific.

The ultrasonic flaw detector 8 and the data recording processor 9 constitute the above-mentioned judgment processing unit. The judgment processing unit is connected to the input unit of the ultrasonic flaw detector 8 as shown in FIGS. The output units of the flaw detection probe 7 and the water immersion confirmation probe 6 are connected to each other, and the output unit of the ultrasonic flaw detector 8 is connected to the input unit of the data recording processing device 9. Although not shown in the figure, the data recording processing unit 9 is provided with a display means such as a CRT, a printer for recording data contents, and the like, so that an operator can observe the display means. .

Next, the flaw detecting probe 7,
The specific structure of the water immersion checking probe 6 and the blade leg boundary detection sensor 5 will be described with reference to FIG. That is, FIG.
As shown in (b) and (c), the flaw detection head 4 has a frame 41 on which the blade leg boundary detection sensor 5 is mounted, and one end of a feed screw 42 is connected to an intermediate portion of the frame 41. The handle 4 is attached to the other end of the feed screw 42.
3 is attached, and the feed screw 42 is supported so as to be rotatable around the axis by operating the handle 43. The flaw detection probe 7 is mounted at an intermediate position of the feed screw 42 via an elastic support 44, and when the blade leg boundary detection sensor 5 is positioned at the boundary position 12, the operator operates the handle 43. Then, the feed screw 42 is rotated around the axis, and the flaw-detecting probe 7 is moved along the axial direction on the feed screw 42 so as to be positioned on the projection 32b of the wheel saddle type portion 32a to be inspected. I have.

This is because when the angle at which the flaw detection probe 7 emits ultrasonic waves is constant and the distance between the flaw detection probe 7 and the blade leg boundary detection sensor 5 is small as shown in FIG. If the reflected beam 7b of the ultrasonic wave 7a moves toward the near side from the projection 32b to be inspected and the distance between the reflected beam 7b and the blade leg boundary detection sensor 5 is too large as shown in FIG. This is because it is necessary to appropriately select the position of the flaw detection probe 7 by operating the handle 43 because it moves toward the rear side of the projection 32b.

Therefore, the probe for flaw detection 7 comprises the frame 4
1, feed screw 42, handle 43, elastic support 44
The position with respect to the blade leg boundary detection sensor 5 can be adjusted by the support mechanism composed of. And FIG.
Although the water immersion confirmation probe 2 is not shown in the figure, the probe is basically mounted and positioned similarly to the flaw detection probe 7.

Incidentally, for reference, the principle of detecting a defect such as a crack by the flaw detector 7 is as shown in FIG. 7, and the projection 32b of the saddle-shaped portion 32a is irradiated with ultrasonic waves. If there is no obstacle, the traveling direction is slightly changed on the outer peripheral surface of the projection 32b and propagates forward as a traveling wave 7a '. However, if the defect 10 exists in the projection 32b, the defect The light is reflected by the influence of 10, and most of the light is received by the flaw detector 7 following the incident route in the reverse direction as the reflected beam 7b.

Since the ultrasonic flaw detector according to the embodiment has the above-described configuration, its handling will be described below. At the time of the inspection, the water in the water tank 1 is impregnated with the blade implanted portion composed of the saddle-shaped portion 32a provided on the turbine rotor 30 and the blade 33 attached thereto. To fill the gap between the two.

When the water is full, the scanning table 2 is mounted on the rim 32d of the turbine rotor 30, the scanning table 2 is moved, and a blade as a defect detector is inserted into an arbitrary blade implantation portion from the side. The leg boundary detection sensor 5, the water immersion confirmation probe 6, and the flaw detection probe 7 are positioned by the support mechanism. In this case, the water immersion confirmation probe 6 confirms that water is filled in the gap 11 between the projection 32b of the saddle-shaped portion 32a of the blade implantation portion to be inspected and the blade leg 33a. After the blade leg boundary detection sensor 5 confirms the boundary position 12 between the blade implantation portion to be inspected and the blade blade implantation portion adjacent thereto, the inspection object 7 is inspected by the flaw detection probe 7. Irradiate the blades with ultrasonic waves.

In this case, the flaw detection probe 7 irradiates the ultrasonic waves from the base side surface side of the blade leg 33a in the blade implanting part toward the boundary position 12 adjacent to each other, and the ultrasonic waves are irradiated. Since the reflected ultrasonic waves 7b are reflected by the end face of the adjacent saddle-shaped portion 32a and the reflected ultrasonic waves 7b are directed to the saddle-shaped portion projection 32b, it is possible to detect whether or not a defect 10 such as a crack exists in the projection 32b. it can.

When the inspection of the inspection object is completed, the turbine rotor 30 is rotated and positioned at a predetermined angle around the axis, and a new inspection site is inspected in the same manner as described above. Inspection section will be inspected.

As described above, in the embodiment, the ultrasonic wave from the flaw detection probe 7 is irradiated from the base side surface of the blade leg 33a toward the boundary position 12 where the blade implanted portions are adjacent to each other. Since the presence or absence of the defective portion 10 is detected by being reflected by the end surface 13 of the adjacent saddle-shaped portion 32a and traveling toward the projection 32b, the ultrasonic wave from the base side of the saddle-shaped portion 32a in the turbine rotor 30 is detected. And the ultrasonic wave is reflected at the tip of the saddle-shaped portion 32a to detect a defective portion. Without, it is possible to reliably irradiate the projection 32b with ultrasonic waves,
The defective portion 10 can be accurately detected. Moreover, when the ultrasonic wave is irradiated as described above, the beam length can be shortened, so that not only the beam is not attenuated but also the noise is not generated in the beam, and the defect 10
Can be detected stably.

In the embodiment shown in the drawings, as the detecting means, the protrusion 32b of the saddle-shaped portion 32a and the blade 33
Probe 6 for detecting whether or not the gap is filled with water, a probe 6 for detecting immersion, a probe 7 for detecting whether or not there is a defective portion 10, and a probe for inspection. A blade leg boundary position detection sensor 5 for detecting a boundary position 12 between the blade implantation portion and the adjacent blade implantation portion and specifying a detection position of the flaw detector 7; Since a defective portion can be detected by having a specific detection function, the defective portion 10 can be detected stably and satisfactorily. In addition, the water immersion confirmation probe 6, the flaw detection probe 7, and the blade leg boundary position detection sensor 5 are provided by a flaw detection head 4 provided on the scanning table 2.
And the support mechanism supports the positions of the water immersion confirmation probe 6 and the flaw detection probe 7 with respect to the blade leg boundary position detection sensor 5 so as to be adjustable. 7 can be easily positioned with respect to the inspection target site.

[0031]

As described above, according to the first and second aspects of the present invention,
According to 2, the ultrasonic wave from the detection means is irradiated from the base side surface side of the blade leg to be inspected toward the boundary position of the blade leg adjacent to the blade implanted portion, and the adjacent saddle-shaped portion is irradiated. It is configured to detect the presence or absence of a defect by reflecting on the end surface of the wheel and heading toward the projection to be inspected, so it may be affected by the geometric shape and dimensions of the wheel base side and the blade implantation part. In addition, it is possible to reliably irradiate the inspection object with ultrasonic waves, and it is possible to accurately detect a defective portion.Besides, since the beam length can be shortened, not only does the beam not be attenuated, but also There is an effect that stable detection can be performed without the risk of generating noise or the like in the beam. In particular, according to the second aspect, since each of the detecting means has a specific detecting function, the defective portion can be detected, so that the defective portion can be detected stably and satisfactorily.

According to a third aspect of the present invention, the detecting means is mounted on a scanning table movable along the outer periphery of the rim of the turbine rotor, and is immersed in water relative to the blade leg boundary detecting sensor of the detecting means. Since it has a support mechanism that can adjust the positions of the checking probe and the flaw detecting probe, each of the blade leg boundary detection sensor, the water immersion checking probe, and the flaw detecting probe can be used as inspection target parts. On the other hand, there is an effect that positioning can be easily performed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of an ultrasonic flaw detector according to the present invention.

FIG. 2 is an explanatory diagram when ultrasonic waves are irradiated to a turbine rotor blade implanted portion by a water immersion confirmation probe and a flaw detection probe.

FIG. 3 A blade leg boundary detection sensor as a detector, a water immersion confirmation probe, and a flaw detection probe are attached to the turbine rotor blade implanting portion, and each probe is attached to the turbine rotor blade implanting portion. FIG. 3 is an explanatory perspective view showing a state of an ultrasonic beam emitted from a child.

FIGS. 4A and 4B are an explanatory diagram showing a configuration of a blade leg boundary detection sensor and an explanatory diagram showing an output waveform thereof.

FIG. 5 is an explanatory view showing a support mechanism of a blade leg boundary detection sensor and a flaw detection probe.

FIG. 6 is an explanatory diagram showing the direction of an ultrasonic beam when the distance between the blade leg boundary detection sensor and the flaw detection probe is changed with respect to the inspection object.

FIG. 7 is an explanatory view showing the principle of detecting a defect such as a crack by ultrasonic waves from a flaw detection probe.

FIG. 8 is an explanatory view showing a steam turbine rotor and a structure for mounting wheels and blades thereof.

FIG. 9 is an explanatory view showing an example of a conventional ultrasonic flaw detector.

FIG. 10 is an explanatory view showing a problem when a conventional ultrasonic flaw detector is used.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Water tank, 2 ... Scanning table, 4 ... Flaw detection head, 5 ... Blade leg boundary detection sensor, 6 ... Water immersion confirmation probe, 7 ... Flaw detection probe, 8 ... Ultrasonic flaw detector, 9 ... Data recording processing device, 1
0: defective portion, 11: boundary position, 12: boundary position between adjacent blade implant portions, 30: turbine rotor, 32: wheel, 32a: saddle-shaped portion, 32b: protrusion, 33: blade,
33a ... leg, 33b ..., hook groove.

Continued on the front page (72) Inventor Yoji Yoshida 3-2-1 Sachimachi, Hitachi City, Ibaraki Prefecture Inside Hitachi Engineering Co., Ltd. (72) Inventor Hiroaki Chiba 3-1-1 Sachimachi, Hitachi City, Ibaraki Stock Inside the Hitachi Plant of Hitachi, Ltd.

Claims (3)

[Claims] An ultrasonic wave is applied to a blade implanting portion including a plurality of saddle-shaped portions provided on an outer periphery of a turbine rotor along an axial direction and blades fitted and assembled to the saddle-shaped portion. In a flaw detection device for detecting a defect such as a crack present in a projection of a saddle-shaped portion, a blade implanted portion to be inspected for a turbine rotor is impregnated with water, and the saddle-shaped portion of the blade implanted portion is inspected. A water tank that fills the gap between the projection and the leg of the blade with water,
When the gap between the projection of the saddle-shaped portion and the leg of the blade in the blade implantation portion is filled with water, the boundary between the blade implantation portion to be inspected and the adjacent blade implantation portion. position,
Ultrasonic waves are radiated from the tip side surface of the saddle portion to be inspected, and the ultrasonic waves are reflected on the end surface of the adjacent saddle portion, face the projections of the saddle portion to be inspected, and are present on the projections. And a detecting means for detecting the presence / absence of a defective portion. 2. An ultrasonic wave is applied to a blade implanting portion including a plurality of saddle-shaped portions provided on an outer periphery of a turbine rotor along an axial direction and blades fitted and assembled to the saddle-shaped portion. In a flaw detection device for detecting a defect such as a crack present in a projection of a saddle-shaped portion, a blade implanted portion to be inspected for a turbine rotor is impregnated with water, and the saddle-shaped portion of the blade implanted portion is inspected. A water tank that fills the gap between the projection and the leg of the blade with water,
When the gap between the projection of the saddle-shaped portion and the leg of the blade in the blade implantation portion is filled with water, the boundary between the blade implantation portion to be inspected and the adjacent blade implantation portion. position,
Ultrasonic waves are radiated from the tip side surface of the saddle portion to be inspected, and the ultrasonic waves are reflected on the end surface of the adjacent saddle portion, face the projections of the saddle portion to be inspected, and are present on the projections. Detecting means for detecting the presence or absence of a defective portion, wherein the detecting means detects whether or not a gap between the projection of the saddle-shaped portion to be inspected and the leg of the blade is filled with water. Ultrasonic waves are applied to the boundary between the probe for confirmation and the saddle-shaped portion to be inspected and the adjacent saddle-shaped portion from the tip side surface of the saddle-shaped portion to be inspected. A flaw detection probe that reflects from the end face of the adjacent saddle-shaped portion toward the projection of the saddle-shaped portion to be inspected, and detects the presence or absence of a defect existing in the projection; and a saddle-shaped portion to be inspected. Wing leg for detecting the boundary position between the probe and its adjacent saddle-shaped portion and specifying the ultrasonic irradiation position of the flaw-detecting probe Boundary detector and a turbine rotor blade implanting portion ultrasonic inspection apparatus characterized by comprising a. 3. The detection means is mounted on a scan table movable on a rim of a turbine rotor along an outer periphery thereof,
3. The turbine rotor according to claim 1, further comprising a support mechanism capable of adjusting the positions of the probe for detecting water immersion and the probe for flaw detection with respect to the blade leg boundary detection sensor of the detection means. Ultrasonic flaw detector for blade implant.