JP2012042298A - Ultrasonic flaw detection device for different-material welding rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of accuracy and reliability of ultrasonic flaw detection without requiring scanning of ultrasonic probes in the horizontal direction.SOLUTION: Since the ultrasonic flaw detection device for different-material welding rotor is constituted so as to calculate a depth position of a defect F included in a flaw detection area based on processing of a TOFD method by combination of a first ultrasonic probe 11 (transmission probe) and a second ultrasonic probe 12 (reception probe) and to calculate a horizontal direction position of the defect F, namely, a type of the defect F by combination of the first ultrasonic probe 11 (transmission probe) and third ultrasonic probes 13L, 13R (reception probes), it becomes unnecessary to scan the ultrasonic probes in the horizontal direction as in a conventional configuration, and the deterioration of accuracy and reliability of the ultrasonic flaw detection is prevented even in a situation that a sufficient scanning space can not be secured.

Description

  The present invention relates to an ultrasonic flaw detection apparatus for a dissimilar material welded rotor in which a welded portion of a dissimilar material welded rotor formed by welding two members of different materials is used as a flaw detection region.

  Conventionally, a large-sized forged product integrally formed of the same material has been used for a turbine rotor of a steam turbine power plant. A high temperature strength is required for the high temperature portion of the turbine rotor, and a condition that toughness is required for the low temperature portion must be satisfied at the same time. Therefore, it is necessary to use a special material. And since it is a special material, the output capacity of the turbine rotor could not be increased beyond a certain level, which was disadvantageous in terms of cost. Further, since it is a large forged product, a long production period is required.

  By the way, in recent years, there has been an increasing need for higher output capacity, lower costs, shorter delivery times, and the like for turbine rotors. To meet these needs, two different materials for high temperature members and low temperature members are used. A dissimilar material welding rotor formed by welding members is gradually being used.

  However, a defect may occur at a welding point of the dissimilar material welding rotor due to a defect during welding work, and the presence of this defect causes a problem such as insufficient strength. Therefore, for dissimilar material welded rotors, it is important to perform quality inspections of welded parts using ultrasonic flaw detection and other methods after welding and during regular maintenance to confirm that no defects have occurred. become.

  Here, as the types of main defects generated at the welded portion of the dissimilar material welded rotor, there are “blow hole” and “fusion failure”. The blow hole is a spherical cavity generated in the weld bead and is generated not near the groove surface but near the center of the weld metal. On the other hand, poor fusion occurs due to the fact that the boundary surfaces between the weld metal and the member are not sufficiently melted together, and occurs near the groove surface. The occurrence of poor fusion results in lower weld strength than the occurrence of blowholes. Therefore, whether the type of defect at the weld is a blowhole or poor fusion is a matter of evaluating the strength of the turbine rotor. It becomes important information. Therefore, in the ultrasonic flaw detection, in addition to the size (length) and depth position of the defect at the weld location, information on the horizontal position (defects generated near the groove surface or near the center). ) Is required to get.

  FIG. 7 is an explanatory diagram showing the configuration of the dissimilar material welding rotor and the scanning direction in ultrasonic flaw detection. The dissimilar material welding rotor R is formed by welding a first rotor member R1 and a second rotor member R2 made of different materials. Between the first rotor member R1 and the second rotor member R2, there is a welding point Z that becomes an ultrasonic flaw detection region.

  The ultrasonic probe is scanned in the circumferential direction (arrow Y1) in order to detect defects that may be present inside the welded part Z. In order to identify the type of detected defect, horizontal scanning is performed. Direction scanning (arrow Y2) must also be performed. For example, if the detected defect F1 is near the center of the weld point Z, the type of the defect F1 is a blow hole, and the detected defect F2 is near the groove surface (edge) of the weld point Z. In the vicinity of the portion), it can be seen that the type of the defect F2 is poor fusion.

  Examples of ultrasonic flaw detection methods include an edge echo method, a TOFD method, and a SPOD method as introduced in Patent Document 1.

  FIG. 8 is an explanatory view of a conventional apparatus for performing ultrasonic flaw detection by an end echo method on a welded portion of a dissimilar material welding rotor, (a) is a partially enlarged sectional view, and (b) is (a). It is a wave form diagram of the echo which the ultrasonic probe in FIG. Receives.

  In FIG. 8A, the transmitting / receiving ultrasonic probe 1 is disposed on the surface of the second rotor member R2 via the oblique shoe 2 to the right of the welding point Z. The oblique shoe 2 is for securing a predetermined flaw detection angle θ of the ultrasonic probe 1 with respect to the welded portion Z that is a flaw detection area.

  The ultrasonic probe 1 performs circumferential scanning (see arrow Y1 in FIG. 7) at the horizontal position P1, but now receives an echo signal W1 from the upper end of the defect F1 at a certain rotation angle. . Next, when the ultrasonic probe 1 moves to the horizontal position P2 and performs the same circumferential scanning, it receives the echo signal W2 from the lower end of the defect F1 at the same rotation angle.

  Since the echo levels of the echo signals W1 and W2 at this time have a peak shape as shown in FIG. 8B, a defect F1 having a magnitude proportional to the distance between P1 and P2 in the welding point Z from now on. Can be detected. It should be noted that the horizontal position of the defect F1 (the position at the substantially central portion of the welding point Z) and the depth position (vertical position) can be obtained from data such as the flaw detection angle θ and the position P1.

  FIG. 9 is an explanatory view of a conventional apparatus for performing ultrasonic flaw detection by the TOFD method on a welded portion of a dissimilar material welding rotor, (a) is a partially enlarged sectional view, and (b) is a reception in (a). It is a wave form diagram of the echo which the ultrasound probe receives.

  In FIG. 9A, the transmitting ultrasonic probe 3 is disposed on the surface of the first rotor member R1 via the oblique shoe 2 on the left side of the welding point Z that is a flaw detection region. On the other hand, at the position to the right of the welding point Z and symmetrical to the transmitting ultrasonic probe 3, the receiving ultrasonic probe 4 is connected to the second rotor member via the oblique shoe 2. Located on the surface of R2. The transmitting ultrasonic probe 3 and the receiving ultrasonic probe 4 are paired to perform circumferential scanning and horizontal scanning as in the case of the end echo method, and receive ultrasonic waves at a certain position. The acoustic probe 4 receives a lateral wave α, diffracted waves β1, β2, and a bottom reflected wave γ.

  The reception timing of these lateral waves α, diffracted waves β1, β2, and bottom surface reflected wave γ is as shown in FIG. 9B, and the size of the defect F1 is obtained from the arrival time difference of the diffracted waves β1, β2 and the sound velocity. In addition, the horizontal position of the defect F1 (the position at the substantially central portion of the welding point Z) is determined from the horizontal position of the transmitting ultrasonic probe 3 and the receiving ultrasonic probe 4. Can be sought.

  10A and 10B are explanatory views of a conventional apparatus for performing ultrasonic flaw detection by the SPOD method on a welded portion of a dissimilar material welding rotor, FIG. It is a wave form diagram of the echo which the ultrasound probe receives.

  In FIG. 10A, the transmitting ultrasonic probe 3 is disposed on the surface of the first rotor member R1 via the oblique shoe 2 on the left side of the welding point Z, which is a flaw detection region. On the other hand, the receiving ultrasonic probe 4 is directly disposed on the surface of the welding point Z without the bevel shoe 2 interposed therebetween. The transmitting ultrasonic probe 3 and the receiving ultrasonic probe 4 are paired to perform circumferential scanning and horizontal scanning as in the case of the end echo method and the TOFD method, and at a certain position. The receiving ultrasonic probe 4 receives a lateral wave α, a diffracted wave β, and a bottom reflected wave γ.

  The reception timing of these lateral wave α, diffracted wave β, and bottom surface reflected wave γ is as shown in FIG. 10B, and the size of the defect F1 can be obtained from the echo level of the diffracted wave β (the simulated defect is detected). The relationship between the echo level and the defect length is acquired in advance with the applied calibration specimen of the same material). Further, the horizontal position of the defect F1 (such as the position of the substantially central portion of the welding point Z) can be obtained from the horizontal positions of the transmitting ultrasonic probe 3 and the receiving ultrasonic probe 4. it can.

JP 2007-315820 A

  As described above, in order to specify whether the defect generated in the welded part of the dissimilar material welding rotor is a blowhole or poor fusion, the horizontal occurrence position of the defect is near or at the center of the groove surface of the welded part. It must be detected whether it is near the part. However, each of the conventional ultrasonic flaw detection methods such as the end echo method, the TOFD method, and the SPOD method all require scanning of the ultrasonic probe in the horizontal direction.

  The dissimilar material welded rotor has a sufficient scanning space near the welded spot immediately after welding, but because it is a turbine rotor, the moving blade is finally attached, so the scanning space is also narrow. Become. Therefore, during regular maintenance, a sufficient scanning space cannot be secured, and it has not been possible to prevent the accuracy and reliability of ultrasonic flaw detection from being deteriorated.

  The present invention has been made in view of the above circumstances, and is a dissimilar material that can prevent deterioration in accuracy and reliability of ultrasonic flaw detection without requiring horizontal scanning of the ultrasonic probe. An object of the present invention is to provide an ultrasonic flaw detector for a welding rotor.

  According to an embodiment of the present invention, as a means for solving the above-described problems, a welding region of a dissimilar material welding rotor formed by welding a first rotor member and a second rotor member made of different materials is inspected. In the ultrasonic flaw detector for a dissimilar material welded rotor, the first and second rotor members are disposed opposite to each other at positions on the surfaces of the first rotor member and the second rotor member, with the welding point being sandwiched in the center. The first ultrasonic probe and the second ultrasonic probe, one of which transmits ultrasonic waves obliquely to the flaw detection area and the other of which receives the ultrasonic waves, and the first ultrasonic wave The first ultrasonic probe is disposed at a position on a straight line connecting the probe and the second ultrasonic probe and on the surface of the welding point or a portion near the welding point. Or an ultrasonic sound transmitted from one of the second ultrasonic probes And processing the other ultrasonic reception data of the third ultrasonic probe for receiving the first ultrasonic probe and the second ultrasonic probe using the TOFD method Welding defect position calculation for obtaining the depth position of the defect contained in the flaw detection area and obtaining the horizontal position of the defect contained in the flaw detection area based on the ultrasonic reception data of the third ultrasonic probe Means.

  According to the present invention, it is possible to prevent a decrease in accuracy and reliability of ultrasonic flaw detection without requiring horizontal scanning of the ultrasonic probe.

Explanatory drawing which shows the structure of the 1st Embodiment of this invention. When the probe holder 14 in FIG. 1 rotates integrally along the circumferential direction (arrow Y1) surface of the dissimilar material welding rotor R, the ultrasonic transmission path and the reception path of each probe at a certain rotation angle are shown. The partial expanded sectional view shown. 3 is a time chart showing the ultrasonic reception timing of each reception probe in FIG. 2, (a) is the reception timing of the second ultrasonic probe 12, and (b) is the reception timing of the left probe 13L. , (C) shows the reception timing of the right probe 13R. 3 is a time chart showing the ultrasonic reception timing of the third ultrasonic probe 13 when the defect F in FIG. 2 is present in the vicinity of the left groove surface (broken line portion), and (a) is a left probe 13L. (B) shows the reception timing of the right probe 13R. The block diagram which shows the structure of the 2nd Embodiment of this invention. The block diagram which shows the structure of the 3rd Embodiment of this invention. Explanatory drawing which shows the scanning direction in the structure of the dissimilar material welding rotor used as the application object of a prior art and this invention, and ultrasonic testing. It is explanatory drawing of the conventional apparatus for implementing the ultrasonic flaw detection by the edge part echo method with respect to the welding location of a dissimilar material welding rotor, (a) is a partial expanded sectional view, (b) is an ultrasonic probe in (a). It is a wave form diagram of the echo which a tentacle receives. It is explanatory drawing of the conventional apparatus for implementing the ultrasonic flaw detection by the TOFD method with respect to the welding location of a dissimilar material welding rotor, (a) is a partial expanded sectional view, (b) is the ultrasonic detection for reception in (a). It is a wave form diagram of the echo which a tentacle receives. It is explanatory drawing of the conventional apparatus for implementing the ultrasonic flaw detection by SPOD method with respect to the welding location of a dissimilar material welding rotor, (a) is a partial expanded sectional view, (b) is the ultrasonic detection for reception in (a). It is a wave form diagram of the echo which a tentacle receives.

  FIG. 1 is an explanatory diagram showing the configuration of the first embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to FIG. 7, and the overlapping description is abbreviate | omitted.

  On each surface of the first rotor member R1 and the second rotor member R2 constituting the dissimilar material welding rotor R, the first ultrasonic probe 11 and the second ultrasonic probe are disposed through the oblique shoes 2. The child 12 is disposed so as to face each other with the welding point Z sandwiched in the center.

  The first rotor member R1 and the second rotor member R2 are located on a straight line connecting the first ultrasonic probe 11 and the second ultrasonic probe 12 and adjacent to the welding point Z. The left probe 13L and the right probe 13R that receive the ultrasonic waves transmitted from the first ultrasonic probe 11 are disposed at positions on the respective surfaces. The left probe 13L and the right probe 13R constitute a third ultrasonic probe 13.

  The left probe 13L and the right probe 13R constituting the first ultrasonic probe 11, the second ultrasonic probe 12, and the third ultrasonic probe 13 are the probe. It is housed together in the child holder 14 and moves integrally along the circumferential direction (arrow Y1) surface of the dissimilar material welding rotor R.

  The first ultrasonic probe 11 is connected to the ultrasonic transmission controller 15, and performs an ultrasonic transmission operation by a control signal from the ultrasonic transmission controller 15. The second ultrasonic probe 12, the left probe 13L, and the right probe 13R are connected to the ultrasonic reception controllers 16 to 18, respectively, and receive the received echo signals. The data is sent to the controllers 16-18.

  The welding defect position calculating means 19 analyzes the echoes sent to the ultrasonic reception controllers 16 to 18 to calculate the welding defect position. Then, the welding defect position calculation means 19 processes the ultrasonic reception data from the second ultrasonic probe 12 by using the TOFD method, whereby the depth of the defect included in the flaw detection region at the weld point Z ( In addition to obtaining the position of the dissimilar material welding rotor R), information on the horizontal position of the defect included in the flaw detection area of the weld point Z based on the ultrasonic reception data from the left probe 13L and the right probe 13R ( Information on whether the defect occurred near the groove surface or near the center) is obtained.

  Here, the arrangement configuration of each probe shown in FIG. 1 is that if the left probe 13L and the right probe 13R are viewed as one third ultrasonic probe 13, the TOFD method and the SPOD are used. It can be considered that the legal arrangement is adopted at the same time. That is, the first ultrasonic probe 11 and the second ultrasonic probe 12 are arranged to perform processing of the TOFD method, and the first ultrasonic probe 11 and the third ultrasonic wave are arranged. The probe 13 (the left probe 13L and the right probe 13R) has an arrangement configuration for performing the SPOD method.

  However, both the TOFD method and the SPOD method are originally processing for determining the depth position of the defect, but in the case of the configuration of FIG. 1, the first ultrasonic probe corresponding to the SPOD method arrangement configuration. The eleventh and third ultrasonic probes 13 function as means for obtaining not the depth position of the defect but the horizontal position of the defect (position near the groove surface or near the center). It has become.

  Next, the operation of the first embodiment will be described. FIG. 2 shows an ultrasonic transmission path and a reception path of each probe at a certain rotation angle when the probe holder 14 rotates integrally along the circumferential direction (arrow Y1) surface of the dissimilar material welding rotor R. It is a partial expanded sectional view.

  Among the ultrasonic waves (longitudinal waves) transmitted from the first ultrasonic probe 11, the ultrasonic waves propagating along the member surface become lateral waves αL, αR, α, respectively, and the left probe 13L, the right side, respectively. It is received by the probe 13R and the second ultrasonic probe 12. In addition, when a defect F exists in the welded part Z, the ultrasonic wave transmitted toward the defect F is reflected at the upper end and the lower end thereof, and becomes diffracted waves β1, β2, and the second ultrasonic probe. Received by the toucher 12. Then, the ultrasonic wave reflected from the bottom surface of the welding point Z becomes a bottom surface reflected wave γ and is received by the second ultrasonic probe 12 and becomes bottom surface reflected waves γL, γR and the left probe 13L. And received by the right probe 13R.

  FIG. 3 is a time chart showing the ultrasonic reception timing of each reception probe in FIG. 2, wherein (a) is the reception timing of the second ultrasonic probe 12, and (b) is the left probe. The reception timing of 13L, (c) shows the reception timing of the right probe 13R.

  The welding defect position calculation means 19 obtains the depth position H of the defect F from the arrival time difference between the lateral wave α and the diffracted wave β1 in (a), and the length L of the defect F from the arrival time difference between the diffracted waves β1, β2. Ask for. In addition, since the reception timing of the diffracted wave β1L in (b) and the diffracted wave β1R in (c) is almost the same, the welding defect position calculation means 19 has the horizontal position of the defect F at the center of the welding point Z. It is determined that the area is near the section. From this discrimination result, it can be seen that the type of the defect F is a blow hole.

  On the other hand, if the horizontal position of the defect F is in the vicinity of the left groove surface of the welding point Z (position indicated by the broken line), the reception timings of the diffracted waves β1L and β1R are as shown in FIGS. As shown, the diffracted wave β1L is slightly faster. Thereby, the welding defect position calculating means 19 can determine that the horizontal position of the defect F is in the vicinity of the left groove surface of the welding point Z. From this determination result, the type of the defect F is poor fusion. I understand that. If the horizontal position of the defect F is in the vicinity of the right groove surface of the weld point Z, the reception timings of the diffracted waves β1L and β1R are in the reverse order as described above. It can be determined that the defect F exists in the vicinity.

  As described above, in the configuration of FIG. 1, the TOFD method is processed by combining the first ultrasonic probe 11 (transmission probe) and the second ultrasonic probe 12 (reception probe). Based on this, the depth position of the defect F included in the flaw detection area is obtained, and the first ultrasonic probe 11 (transmission probe) and the third ultrasonic probes 13L and 13R (reception probes). Thus, the horizontal position of the defect F, that is, the type of the defect F is obtained, so that it is not necessary to scan the ultrasonic probe in the horizontal direction as in the conventional configuration, and a sufficient scanning space cannot be secured. Even in the situation, it is possible to prevent the accuracy and reliability of ultrasonic flaw detection from deteriorating.

  In the configuration of FIG. 1, two probes, the left probe 13L and the right probe 13R, are used as the third ultrasonic probe 13, but only one probe is used. A configuration is also possible. In this case, this single probe is arranged in the center on the surface of the welding point Z, and the reception timing when the horizontal position of the defect F exists in the center is stored in the memory as a reference timing in advance. deep. If the actual reception timing substantially coincides with the reference timing, it is determined that the defect exists near the center. On the other hand, if the actual reception timing is earlier than the reference timing, it is determined that the defect exists near the left groove surface, and if the actual reception timing is later than the reference timing, the defect is determined. Is determined to exist near the right groove surface. In this way, even when only one probe is used as the third ultrasonic probe 13, the same effect as that of the configuration of FIG. 1 can be obtained.

  FIG. 5 is a block diagram showing a configuration of the second exemplary embodiment of the present invention. In this embodiment, the transmission / reception functions of the first ultrasonic probe 11 and the second ultrasonic probe 12 can be switched.

  In FIG. 5, a changeover switch 20 is provided between the first ultrasonic probe 11 and the second ultrasonic probe 12 and the ultrasonic transmission controller 15 and the ultrasonic reception controller 16. The changeover switch 20 has movable contacts 21 and 22 that can switch between terminals a and b. In the present embodiment, the first ultrasonic probe 11 and the second ultrasonic probe 12 are of a transmission / reception type.

  Next, the operation of the second embodiment will be described. As shown in the drawing, in a state where the movable contact 21 is in contact with the terminal a and the movable contact 22 is in contact with the terminal b, the first ultrasonic probe 11 is connected to the ultrasonic transmission controller 15. In addition, the second ultrasonic probe 12 is connected to the ultrasonic reception controller 16. Therefore, the first ultrasonic probe 11 functions as a transmission probe, and the second ultrasonic probe 12 functions as a reception probe.

  Further, when the switching operation or the switching control of the changeover switch 20 is performed so that the movable contact 21 is in contact with the terminal b side and the movable contact 22 is in contact with the terminal a side (a state illustrated by a broken line), the second ultrasonic probe is performed. The transducer 12 is connected to the ultrasonic transmission controller 15, and the first ultrasonic probe 11 is connected to the ultrasonic reception controller 16. Therefore, the second ultrasonic probe 12 functions as a transmission probe, and the first ultrasonic probe 11 functions as a reception probe.

  Then, after performing ultrasonic flaw detection with the movable contact 21 in contact with the terminal a side and the movable contact 22 in contact with the terminal b side, contact switching is performed. This time, the movable contact 21 is in contact with the terminal b side and is movable. The ultrasonic flaw detection is performed again with the contact 22 in contact with the terminal a.

  The welding defect position calculation means 19 calculates the welding defect position using the addition average of the received data obtained by the above two ultrasonic flaw detections. Therefore, it is possible to prevent an error of the ultrasonic probe itself or an error caused by the probe mounting position from increasing, and to prevent a decrease in accuracy and reliability of the ultrasonic flaw detection. . In addition, when the changeover switch 20 is switched, it is possible to obtain a secondary effect that it is possible to estimate that some abnormality has occurred when there is a large fluctuation in the obtained data.

  FIG. 6 is a block diagram showing the configuration of the third exemplary embodiment of the present invention. In this embodiment, reception control of three reception ultrasonic probes can be performed by a single ultrasonic reception controller.

  In FIG. 6, a selection switch 23 is provided between the second ultrasonic probe 12 and the third ultrasonic probes 13 </ b> L and 13 </ b> R and the ultrasonic reception controller 16. This selection switch 23 has a movable contact 24 capable of switching between terminals a, b and c. In the present embodiment, it is assumed that the first ultrasonic probe 11 is a transmission-only type and the second ultrasonic probe 12 is a reception-only type. (In this case, the arrangement of the probes 11 and 12 can be interchanged).

  And in this embodiment, when the ultrasonic probes 11-13 rotate integrally along the circumferential direction (arrow Y1 of FIG. 1) surface of the dissimilar material welding rotor R, in the rotation position for every predetermined angle, The terminals with which the movable contact 24 contacts are sequentially switched from a → b → c. That is, any one of the second ultrasonic probe 12, the left probe 13 </ b> L, and the right probe 13 </ b> R performs cyclic sequential reception operations based on the control of the ultrasonic reception controller 16. .

  Therefore, according to the configuration of the present embodiment, reception control for three ultrasonic probes can be performed by a single ultrasonic reception controller, and costs can be reduced.

  As mentioned above, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

R: Dissimilar material welding rotor R1: First rotor member R2: Second rotor member Z: Welding points F, F1, F2: Defects α, αL, αR: Lateral waves β1, β1L, β1R, β2: Diffraction wave γ, γL, γR: Bottom reflected wave 1: Ultrasonic probe (for both transmission and reception)
2: Bevel shoe 3: Transmission ultrasonic probe 4: Reception ultrasonic probe 11: First ultrasonic probe 12: Second ultrasonic probe 13: Third ultrasonic Probe 13L: Left probe 13R: Right probe 14: Probe holder 15: Ultrasonic transmission controllers 16-18: Ultrasonic reception controller 19: Weld defect position calculating means 20: Changeover switch 21, 22: movable contact 23: selection switch 24: movable contact

Claims (5)

In an ultrasonic flaw detector for a dissimilar material welded rotor having a flaw detection region at a weld point of a dissimilar material welded rotor formed by welding a first rotor member and a second rotor member made of different materials,
Ultrasonic waves that are disposed at positions on the respective surfaces of the first rotor member and the second rotor member so as to face each other with the welding point sandwiched in the center, and are oblique to the flaw detection area A first ultrasonic probe and a second ultrasonic probe in which one of them transmits and the other receives it,
The first ultrasonic probe and the second ultrasonic probe are disposed on a straight line connecting the first ultrasonic probe and the second ultrasonic probe, and are disposed at positions on the surface of the welding point or a vicinity thereof. A third ultrasonic probe for receiving an ultrasonic wave transmitted from one of the ultrasonic probe and the second ultrasonic probe;
The depth position of the defect included in the flaw detection area is obtained by processing the other ultrasonic reception data of the first ultrasonic probe or the second ultrasonic probe using the TOFD method. A welding defect position calculation means for obtaining a horizontal position of a defect included in the flaw detection area based on the ultrasonic reception data of the third ultrasonic probe,
An ultrasonic flaw detector for a dissimilar material welding rotor, comprising: The third ultrasonic probe is composed of two probes respectively disposed at positions adjacent to the welding locations on the surfaces of the first rotor member and the second rotor member.
The ultrasonic flaw detector for a dissimilar material welded rotor according to claim 1. The first ultrasonic probe and the second ultrasonic probe are connected to an ultrasonic transmission controller and an ultrasonic reception controller via a changeover switch so that a transmission function and a reception function can be switched. Being
The ultrasonic flaw detector for a dissimilar material welded rotor according to claim 1 or 2. One of the first ultrasonic probe and the second ultrasonic probe is connected to an ultrasonic transmission controller, and the first ultrasonic probe or the second ultrasonic probe is connected. The other of the transducers and the third ultrasound probe are connected to the ultrasound reception controller via a selection switch so that any one reception function is cyclically exhibited.
The ultrasonic flaw detector for a dissimilar material welded rotor according to claim 1 or 2. The first to third ultrasonic probes are collectively stored in a probe holder and integrally move along the circumferential surface of the dissimilar material welding rotor.
The ultrasonic flaw detector for a dissimilar material welded rotor according to any one of claims 1 to 4.

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