JP5610444B2 - Ultrasonic inspection method and apparatus for welds - Google Patents

Description

  The present invention relates to an ultrasonic inspection method and apparatus for ultrasonically inspecting the soundness of a welded part, and more particularly to an ultrasonic inspection method and apparatus for a welded part of a welding turbine rotor.

  Ultrasonic inspection methods that detect flaws using ultrasonic waves are designed to detect defects by measuring the beam path length and echo height by receiving reflected echoes from defects by injecting ultrasonic waves from the probe into the object to be inspected. This is a method for evaluating the position and size of the. However, in the ultrasonic inspection, not only the reflected echo from the defect but also the shape echo due to the shape of the object to be inspected is received, so it is necessary to determine whether the received echo is a defect echo or a shape echo. In particular, in ultrasonic inspection when a back wave is generated in the weld, it is very important to determine whether the received echo is an echo from a defect or an echo from the back wave. Become. From such a viewpoint, Patent Documents 1 and 2 are given as prior arts for identifying defect echoes and back wave echoes in ultrasonic inspection of welds.

  In Patent Document 1, the spread of the echo image due to the spread of the ultrasonic beam is shrunk by the aperture synthesis method, and the position accuracy of the echo reflection source is increased, whereby the back wave having the back wave position as the reflection source. This discriminates an echo from a defect echo having a position other than the back wave as a reflection source.

  In Patent Document 2, a peak is detected from the waveform of the reflected echo at each scanning position, the peaks at the adjacent scanning positions detected are compared, and those of the same reflection source are grouped. A cell image is created by discriminating whether it is a defect echo or a shape echo and not displaying a peak of the same group as the peak considered as a shape echo as a defect.

JP 2008-249441 A JP 2010-175259 A

  When a part of the ultrasonic path passes through the weld, the sound speed may change between the base material and the weld, and the refraction angle may change between the base material and the weld. There is a possibility not to. However, the above invention does not take into account changes in the sound speed of ultrasonic waves or deviations from the straight propagation path, and it is assumed that the ultrasonic waves travel straight at a constant sound speed and the position of the echo reflection source is highly accurate. The cell image is created by identifying the back echo and the defect echo from the obtained echo position, or by not displaying the same group of peaks as the shape echo as a defect. I guess. Therefore, it is assumed that when the ultrasonic wave does not go straight when passing through the welded portion, the back wave echo and the defect echo cannot be accurately identified.

  An object of the present invention is to provide an ultrasonic inspection method and apparatus capable of reliably identifying back wave echoes and defect echoes even when there is a possibility that ultrasonic waves do not travel straight when passing through a weld.

In order to achieve the above object, in the present invention, there is provided an ultrasonic inspection method for a welded portion of a test object formed from a base material and a welded portion joining the base material, wherein the base material is a bottom surface in the vicinity of the welded portion. Is formed so that the depth is deeper than the bottom surface other than the vicinity of the welded portion, and the surface of the base material and the bottom surface of the welded portion are substantially parallel from the surface of the base material to the bottom surface of the welded portion. A portion formed of a base material, and a shape portion formed in the base material that is located at the same depth as the bottom surface near the welded portion and is surface-reflected when an ultrasonic wave is incident at an oblique angle from the surface of the base material In the ultrasonic inspection method for the welded part of the object to be inspected, the bottom surface depth calculation result in the vicinity of the welded part calculated by the vertical flaw detection method for the part formed by the base material, and the base material and the welded part are passed bottom depth of the weld vicinity calculated at an oblique angle flaw detection method with respect to the shaped portion from the surface of the base material By comparing the calculation result, wherein when the result is confirmed to be consistent, the comparing and the bottom depth of the weld vicinity of the device under test, the depth of the ultrasound echo image, the echo It is characterized by performing identification.

In order to achieve the above object, according to the present invention, there is provided an ultrasonic inspection apparatus for a welded part of an object to be inspected formed from a base material and a welded part joining the base material, wherein the base material is in the vicinity of the welded part. bottom is formed so that the depth becomes deeper than the bottom surface of the non-weld portion near the bottom surface of the welded portion near the surface of the base material bottom surface of the welded portion near the surface of the base material is substantially parallel The shape formed on the base material that is surface-reflected when the ultrasonic wave is incident at an oblique angle from the surface of the base material that is located at the same depth as the bottom surface near the welded part In the ultrasonic inspection apparatus for the welded portion of the object to be inspected having a first portion, a first probe that transmits and receives ultrasonic waves to a portion formed of the base material, and a first supersonic that drives the first probe An ultrasonic flaw detector, first display means for displaying an ultrasonic flaw detection result of the ultrasonic flaw detector, and the first display Calculating the depth of the reflected echo image of the ultrasonic wave received by the probe in the stage and displaying it on the first display means; and the shape from the base material surface passing through the base material and the welded portion. A second probe that transmits and receives ultrasonic waves at an oblique angle with respect to the part, a second ultrasonic flaw detector that drives the second probe, and the sound speed and refraction of the ultrasonic flaw detection result of the second flaw detector Echo image calculation means for correcting the angle and recalculating the depth of the echo image, and second display means for displaying the processing result of the echo image calculation means.

  According to the present invention, in the ultrasonic inspection of the welded portion, even when there is a possibility that the ultrasonic wave does not travel straight when passing through the welded portion, the relative position between the bottom surface of the object to be inspected and the depth of the reflected echo is accurately determined. Since the comparison can be made, the back wave echo of the welded part and the echo other than the back wave (echo from the groove unwelded part, defect echo) can be reliably identified.

It is the block diagram (A) which shows the structure of the ultrasonic inspection apparatus by Example 1 of this invention, and the figure (B) which shows an example of a display screen. It is a flowchart which shows the determination / operation procedure at the time of flaw-detecting the welding part of a to-be-inspected object using the ultrasonic inspection apparatus by Example 1 of this invention. Sectional drawing of the to-be-inspected object which shows the propagation path of an ultrasonic wave, and the position of a reflective echo at the time of flaw detection of the welding part which the correction of sound speed and a refraction angle are unnecessary, and the back wave has generate | occur | produced by Example 1 of this invention It is. Sectional drawing of the to-be-inspected object which shows the propagation path of an ultrasonic wave, and the position of a reflective echo in the case of flaw-detecting the welding part which does not require the correction of a sound speed and a refraction angle, and the back wave does not generate | occur | produce by Example 1 of this invention It is. It is explanatory drawing which shows the example of a display screen of a flaw detection result when the correction of sound speed and a refraction angle is unnecessary according to Example 1 of this invention, and the welded part which the back wave generate | occur | produced is flawed. It is explanatory drawing which shows the example of a display screen of the flaw detection result at the time of flaw detection of the welding part which does not require correction of a sound speed and a refraction angle, and the back wave does not generate | occur | produce by Example 1 of this invention. Sectional drawing of the to-be-inspected object which shows the propagation path of an ultrasonic wave, and the position of a reflective echo in the case of flaw detection of the welding part which needs correction | amendment of a sound speed and a refraction angle according to Example 1 of this invention, and a back wave has generate | occur | produced It is. Sectional drawing of the to-be-inspected object which shows the propagation path of an ultrasonic wave, and the position of a reflective echo in the case of flaw detection of the welding part which needs correction | amendment of a sound velocity and a refraction angle, and the back wave does not generate | occur | produce by Example 1 of this invention It is. It is explanatory drawing which shows the example of a display screen of a flaw detection result when the correction of sound speed and a refraction angle is required, and the welding part which has generated the back wave is flawed by Example 1 of this invention. It is explanatory drawing which shows the example of a display screen of a flaw detection result when the correction of sound velocity and a refraction angle is required, and the welded part which the back wave does not generate | occur | produce is detected by Example 1 of this invention. It is sectional drawing which shows schematic shape of the welding rotor which is a to-be-inspected object of Example 2 of this invention. It is a block diagram which shows the structure of the ultrasonic inspection apparatus by Example 2 of this invention. It is sectional drawing of the to-be-inspected object which shows the propagation path of an ultrasonic wave in the case of flaw-detecting the welding part in which the back wave has generate | occur | produced by Example 2 of this invention, and the position of a reflective echo. It is sectional drawing of the to-be-inspected object which shows the propagation path of an ultrasonic wave in the case of flaw-detecting the welding part which has not generate | occur | produced the back wave by Example 2 of this invention, and the position of a reflective echo. It is explanatory drawing which shows the example of a display screen of the flaw detection result at the time of flaw-detecting the welding part which has generated the back wave by Example 2 of this invention. It is explanatory drawing which shows the example of a display screen of the flaw detection result at the time of flaw-detecting the weld part which has not generate | occur | produced the back wave by Example 2 of this invention. It is a functional block diagram which shows the structure of the ultrasonic inspection apparatus by Example 1 of this invention. It is a functional block diagram which shows the structure of the ultrasonic inspection apparatus by Example 2 of this invention.

  In the present invention, the depth from the surface to be inspected through the ultrasonic propagation path passing only through the base material to the bottom surface, and the shape echo located at the bottom surface detected through the ultrasonic path passing through both the base material and the welded part There is a step of comparing the depths. This solution will be described in detail with reference to FIGS. As shown in FIG. 7, when the back wave 5 is generated in the welded portion, all the weld grooves 7 are welded and do not remain, so the ultrasonic waves pass through the welded weld grooves 7. When the phased array probe 21 detects the oblique angle, the reflected echo from the back wave 5 can be received. However, although the ultrasonic wave passing through the welded portion is propagated through a path like 63b, the ultrasonic wave is transmitted. If the echo position is calculated on the assumption that the vehicle travels straight like 63a, it is calculated that the reflected echo is located not at the actual reflection position 53b but at the position of the echo position 53a assuming the straight travel of the ultrasonic wave. Further, as shown in FIG. 8, when no back wave is generated, the weld groove 7 has both the groove welded portion 7a and the groove unwelded portion 7b. The ultrasonic wave is transmitted through the groove weld portion 7a, but is reflected at the groove unwelded portion 7b. When the oblique angle flaw detection is performed by the phased array probe 21, the reflected echo from the groove unwelded portion 7b can be received. However, if the echo position is calculated on the assumption that the ultrasonic wave travels straight like 64a despite the fact that the ultrasonic wave passing through the welded part propagates along a path like 64b, it is not the actual reflection position 54b. If the reflected echo is positioned at the position of the echo position 54a assuming that the ultrasonic wave goes straight, the calculation is performed. In the example of FIG. 7, since the echo is displayed at a position deeper than the bottom surface 8 of the object to be inspected regardless of whether the position of the reflected echo is 53b or 53a, there is no difference in the determination that it is a back wave echo only in this example. . However, in the example of FIG. 8, since the actual echo position 54 b is a depth that coincides with the bottom surface 8, it is assumed that the echo is straight from the ultrasonic wave even though it should be determined as an echo from the groove unwelded portion. According to the echo position 54a, it is erroneously determined that it is a back wave echo.

  In order to prevent such a misjudgment, in the present invention, the depth from the surface of the object to be inspected through the ultrasonic propagation path passing through only the base material to the bottom surface, and the superstructure passing through both the base material and the welded portion are used. A step of comparing the depths of the shape echoes located on the bottom surface detected by the sound wave path is provided.

  First, the depth of the bottom surface 8 is calculated by vertical flaw detection from the base metal position in the vicinity of the weld shown in the single array probe 11 of FIG. Next, in the phased array probe 21, when the echo position from the shape 3 located at the same depth as the bottom surface 8 does not coincide with the depth of the bottom surface 8 calculated by the single array probe 11 as shown by 52a, The set values of the sound speed and the correction angle are adjusted so that the reflected echo from the shape 3 is displayed at 52b. By performing this adjustment, the echo displayed at the position 53a is displayed at the position 53b at the same depth as the back wave. When the inspection object shown in FIG. 8 is flawed in the same procedure, the reflected echo from the groove unwelded portion 7b is displayed at the position 54b instead of the position 54a. Since the reflected echo 54b is displayed at the same depth as the bottom surface 8, it can be correctly determined that the reflected echo is from the groove unwelded portion.

  Hereinafter, the configuration and operation procedure of the ultrasonic inspection apparatus according to the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1A is a block diagram showing a configuration of an ultrasonic inspection apparatus according to the first embodiment of the present invention. The inspection object 1 has a structure in which a base material 2 is welded by a welding portion 4. A protruding portion is provided in the vicinity of the welded portion, and the bottom surface 8 near the welded portion is deeper than the bottom surface 9 other than in the vicinity of the welded portion. The corners of the protrusions have a shape 3 that reflects ultrasonic waves when oblique flaw detection is performed. The welded portion 4 has an overlay welded portion 6 formed at the time of welding, and it is difficult to place the probe directly on the welded portion. Further, the bottom surface 9 other than the vicinity of the welded portion and the bottom surface 8 near the welded portion are structured such that the probe cannot be directly accessed.

  The ultrasonic inspection apparatus includes a single array probe 11 and a single array flaw detector 12 for vertical flaw detection, a phased array probe 21 for performing flaw detection, a phased array flaw detector 23, and a personal computer. Flaw detection condition setting / signal processing device 24 and display 25. The single array flaw detector 12 sends a drive signal for causing the single array probe 11 to transmit ultrasonic waves. The transmitted ultrasonic wave is reflected by the surface of the object to be inspected, a crack or the like, received again by the single array probe 11, and the signal is taken into the single array flaw detector 12, and the result is displayed on the display unit 13. Is displayed. The phased array flaw detector 23 is a device for generating an electronically generated time delay and transmitting an ultrasonic wave whose direction is controlled from the phased array probe 21. The ultrasonic waves reflected by the surface of the object to be inspected or cracks are received again by the phased array probe 21 and taken into the phased array flaw detector 23. The flaw detection condition setting / signal processing device 24 corrects the velocity and refraction angle of the ultrasonic wave for the acquired data. FIG. 1B shows an example of a screen displayed on the display unit 13 of the single array flaw detector 12. In the ultrasonic waveform, the oscillation pulse 14 and the received reflected echo 15 can be observed. When the base material sound speed of the object to be inspected is input in advance to the sound speed setting section 17 and the cursor 16 is set to the reflected echo 15, the path display section 18 has a function of displaying the automatically calculated path.

  FIG. 17 shows a detailed functional block diagram of the ultrasonic inspection apparatus. The single array flaw detector 12 includes a transmitter 80 and a receiver 81 for transmitting and receiving ultrasonic waves. The data recording unit 82 takes in the received wave signal and temporarily stores it. The path length calculation means 83 calculates the path length from the position of the reflected echo 15 indicated by the cursor 16 to the single array probe 11. Further, the computer 84 outputs or controls the flaw detection result to the display unit 13. The input unit 86 is a device for inputting setting conditions and the like, and is a keyboard or the like. The phased array flaw detector 23 records a delay time control unit 89 that sets an ultrasonic delay time, a transmitter 88 that transmits a transmission signal to the phased array probe 21, a receiver 87 that receives a signal, and a reception signal. A data recording unit 82 and a computer 84 for controlling the phased array flaw detector are included. The depth determination unit 92 of the flaw detection condition setting / signal processing device 24 determines whether or not the calculated depth of the bottom surface 8 near the weld and the echo 52 from the shape 3 coincide with the bottom surface depth. The echo determination unit 93 determines whether the echo is from the back wave, the echo from the unwelded portion of the groove, or the echo from the inside of the weld from the position of the echo and the calculated depth of the bottom surface 8 near the weld. The determination result is displayed by displaying the echo image of the display 25 in different colors or by displaying marks. The echo image calculation means 94 corrects the velocity and refraction angle of the ultrasonic wave based on the set values from the correction angle setting means 95 and the sound speed correction value setting means 96. The flaw detection result is calculated and transmitted to the computer 91. The correction angle setting means 95 and the sound speed correction value setting means 96 may calculate the automatic correction value without receiving an input. The mark setting means 99 is for outputting on the screen a mark 48 indicating the incident position, a display line 49 indicating the cross-sectional shape of the object to be inspected, a linear approximation propagation path 58, a propagation path 57, and the like. The depth cursor setting means 100 receives the calculated depth of the bottom surface 8 near the weld and displays a cursor corresponding to the calculated depth. The depth cursor setting means 100 may directly take in the value calculated by the single array flaw detector 12 even with the input value from the input unit 90.

  The inspection procedure / determination will be described with reference to the flowchart of FIG. First, for example, ultrasonic waves are vertically incident from the position shown in the single array probe 11 of FIG. 3, and the depth of the bottom surface 8 near the welded portion is calculated (F11). FIG. 3 shows an example in which the correction of the ultrasonic velocity and refraction angle is unnecessary and a back wave is generated. When the back wave is generated, the welding groove 7 is completely welded and the ultrasonic wave is transmitted. Next, oblique angle flaw detection is performed with a probe. In this embodiment, the phased array probe 21 electronically scans the weld and its vicinity. A display screen example of the flaw detection result at this time is shown in FIG. On the screen, an electronically scanned inspection range 41, a cursor 42 indicating the surface position of the object to be inspected, and a depth cursor 43 indicating the depth from the surface are displayed. The bottom surface depth calculated in step F11 is input to the depth cursor display unit 44 or received from the single array flaw detector 12, and the depth cursor is adjusted to the bottom surface height, so that the echo 52 from the shape 3 becomes the bottom surface depth. (F13). In the case of FIG. 5, since the depth cursor 43 and the depth of the echo 52 from the shape 3 match, the process proceeds to the next step without correcting the sound speed / refraction angle. Since the position of the echo 53 displayed in FIG. 5 is deeper than the depth of the bottom surface 8 (= display position of the cursor 43) (F15), it is determined that the echo 53 is an echo from the back wave 5 (F17). Since the echo 55 is also displayed in FIG. 5, the display position of the echo 55 and the depth of the bottom surface are compared (F15, F16), and the echo 55 is an echo from within the weld, that is, an echo from the defect 10. judge.

  FIG. 4 shows a cross-sectional view of the case where no correction of the ultrasonic velocity / refraction angle is required but no back wave is generated, and FIG. 6 shows a display screen of the flaw detection result. When no back wave is generated, the weld groove 7 has both the groove welded portion 7a and the groove unwelded portion 7b. The ultrasonic wave is transmitted through the groove weld portion 7a, but is reflected at the groove unwelded portion 7b. As in the case of FIGS. 3 and 5, the bottom surface 8 is flawed by the single array probe 11 to calculate the depth (F11), and the depth cursor 43 is adjusted to the bottom surface depth. In FIG. 6, since the echo 52 from the shape 3 coincides with the bottom surface depth (F13), the process proceeds to the next step without correcting the sound speed and the refraction angle. Since the display position of the echo 54 coincides with the depth of the cursor 43 (F15, F16), the echo 54 is determined to be an echo from the groove unwelded portion (F18). Further, the display position of the echo 55 and the depth of the bottom surface are compared (F15, F16), and it is determined that the echo 55 is an echo from the defect 10.

  FIG. 7 shows a cross-sectional view when the ultrasonic wave speed / refraction angle needs to be corrected and a back wave is generated, and FIG. 9 shows a display screen of the flaw detection result. As before, the bottom surface 8 is flawed with the single array probe 11 to calculate the depth (F11), and the depth cursor 43 is adjusted to the bottom surface depth. In FIG. 9, since the display position of the echo 52a from the shape 3 before correction does not coincide with the depth cursor 43 (F13), the set values of the ultrasonic velocity and refraction angle are corrected (F14).

  Here, a correction method for the set value will be described. In FIG. 7, if the single array probe 11 is positioned above the bottom surface 8, the echo 15 as shown in FIG. 1B can be received, but the position of the single array probe 11 is off the bottom surface 8. In some cases, the echo 15 cannot be received or can be received as an echo of a different path. In FIG. 7, the single array probe 11 is scanned in the left-right direction on the paper surface, the range in which echoes from the bottom surface 8 can be received is examined, and the leftmost probe position is obtained. This position is displayed as a mark 56 indicating the ultrasonic incident position of the single array probe 11 on the flaw detection screen of FIG. A display line 49a indicating the cross-sectional shape of the object to be inspected is displayed at a position directly below the mark 56, and a display line 49b indicating the opposite shape across the weld is displayed according to the position of 49a. To do. The incident position of the phased array probe 21 is shown at a position separated by an amount corresponding to the distance difference between the ultrasonic incident position (mark 56) of the single array probe 11 and the ultrasonic incident position of the phased array probe 21. A mark 48 is displayed. The difference between the refraction angles of the propagation path 58 of the linear approximation from the mark 48 to the echo 52a and the propagation path 57 drawn from the mark 48 to the intersection of the display line 49b and the cursor 43 is obtained and input to the correction angle setting frame 45. Correct the refraction angle. The echo is displayed on the propagation path 57 by correcting the refraction angle. Further, the sound speed correction value is input to the correction sound speed setting frame 46 so that the path of the echo whose angle of refraction is corrected matches the path to the intersection of the display line 49 b and the cursor 43.

  When the echo 52b coincides with the cursor 43 (F13), the echo displayed at the position 53a before correction is also corrected and displayed at the position 53b. Since the display position of the corrected echo 53b is deeper than the cursor 43, the echo 53b is determined to be a back wave echo.

  FIG. 8 shows a cross-sectional view when the ultrasonic wave speed / refraction angle needs to be corrected and no back wave is generated, and FIG. 10 shows a display screen of the flaw detection result. As before, the bottom surface 8 is flawed with the single array probe 11 to calculate the depth (F11), and the depth cursor 43 is adjusted to the bottom surface depth. In FIG. 10, since the display position of the shape echo 52a before correction does not coincide with the depth cursor 43 (F13), the set values of the ultrasonic velocity and refraction angle are corrected (F14). When the sound speed / refraction angle is corrected so that the echo 52b coincides with the cursor 43, the display position of the corrected echo 54b is compared with the depth of the cursor 43 (F15, F16). Since both coincide, the echo 54b is determined as an echo from the groove unwelded portion (F18).

  Next, the configuration and operation procedure of the ultrasonic inspection apparatus according to the second embodiment of the present invention will be described with reference to FIGS.

  FIG. 11 is a cross-sectional view illustrating an outline of a welding rotor 70 that is an object to be inspected according to the second embodiment of the present invention. The high temperature side rotor 71 and the low temperature side rotor 72 that are separately manufactured are welded at the weld portion 4. The inner peripheral side of the welded portion 4 is a cavity 75, and the inside of the cavity 75 cannot be accessed after the end of welding. Therefore, the ultrasonic inspection of the welded portion 4 needs to be performed only by accessing the rotor outer peripheral side. In addition, the build-up weld part on the outer periphery side of the rotor formed at the time of welding in Example 1 is deleted by a grinder or the like, and in this example, it is also possible to arrange a probe directly on the surface of the weld part. .

  FIG. 12 is a block diagram showing the configuration of the ultrasonic inspection apparatus according to the second embodiment of the present invention. In addition, the vicinity of the welded portion 4 of the welding rotor 70 is also enlarged. There is a structure such as a rotor wheel 74 and a packing groove 76 on one side of the welded portion 4, and it is difficult to transmit and receive ultrasonic waves from this side. Ultrasonic waves can be transmitted and received from the side of the rotor shaft 73 opposite to the welded portion 4. A protrusion is provided in the vicinity of the weld and forms a bottom surface 8. Further, the corner of the protruding portion has a shape 3 that reflects ultrasonic waves when oblique flaw detection is performed.

  The ultrasonic inspection apparatus used in the second embodiment includes a phased array probe 20 that transmits longitudinal waves or transverse waves, a flaw detector 23 for phased array, a flaw detection condition setting / signal processing device 24 including a personal computer, and a display 25. The The phased array flaw detector 23 is a device that sends a drive signal for transmitting longitudinal or transverse ultrasonic waves from the phased array probe 20. In addition, it has a function of receiving a reception signal from the phased array probe 20 and displaying it on the display 25 as appropriate. In addition, the flaw detection condition setting / signal processing device 24 composed of a personal computer corrects the velocity and refraction angle of the ultrasonic wave for the acquired data. One probe is used, but the longitudinal wave vertical flaw detection of the base material from the position of 20a, the longitudinal wave electronic scan from the position of 20b, and the electron scan of the transverse wave oblique angle in combination with the shoe 22 can be sequentially performed. Is possible. (In the figure, the phased array probe 20 is shown as 20a, 20b, and 20c depending on the installation position of the phased array probe 20.) The longitudinal wave and the transverse wave are used separately for each flaw detection. This is because is suitable for vertical flaw detection, and the transverse wave is suitable for oblique flaw detection. FIG. 18 shows a detailed functional block diagram of the ultrasonic inspection apparatus. In the first embodiment, a single array probe is used for vertical flaw detection, but in the second embodiment, only a phased array probe is used. The phased array flaw detector in this embodiment is also provided with a path length calculation means 83.

  FIG. 13 shows a cross-sectional view when a back wave is generated, and FIG. 15 shows a display screen of the flaw detection result. FIG. 15 shows a cross-sectional shape diagram 47 (47a is the shape on the outer peripheral side, 47b is the shape on the inner peripheral side), the depth cursor 43, the reflected echo position, and the like of the site to be inspected. First, the phased array probe is arranged at a position 20a in FIG. 13A, and the bottom surface 8 is detected by vertical wave vertical inspection. The depth cursor 43 is made to coincide with the display depth of the bottom echo 51. Next, the probe is placed at a position 20b in FIG. 13B, and the inside of the weld is electronically scanned with a longitudinal wave. On the screen shown in FIG. 15, it is confirmed whether the display depths of the echoes 52p and 50p from the shape 3 and the depth of the cursor 43 match. FIG. 15 shows an example in which both are the same and correction is not necessary. However, if they are not the same, the sound velocity / refraction angle of the ultrasonic wave is corrected and the depth of both is corrected as in the first embodiment. Add steps to match. Finally, in a state where the probe is combined with the shoe 22, the probe is disposed at a position 20c in FIG. 13C, and the vicinity of the bottom of the welded portion is electronically scanned with a transverse wave oblique angle. On the screen shown in FIG. 15, it is confirmed whether the display depth of the echo 52 from the shape 3 matches the depth of the cursor 43. FIG. 15 shows an example in which both are the same and correction is not necessary. However, if they are not the same, the sound velocity / refraction angle of the ultrasonic wave is corrected and the depth of both is corrected as in the first embodiment. Add steps to match. In FIG. 15, the flaw detection results shown in FIGS. 13A, 13B, and 13C are all displayed in an overlapping manner. The depths of the bottom echo 51 and the echoes 52, 52p and 50p from the shape 3 coincide with each other, the echoes 53 and 53p are located deeper than the bottom surface, so that they can be determined as back wave echoes, and the echoes 55 and 55p are from the bottom surface. Since it is located shallow, it can be confirmed that it should be determined as a defect echo.

  In this embodiment, a phased array probe is arranged at the position 20b and the inside of the welded portion is electronically scanned by a longitudinal wave, so that a transverse wave oblique angle electronic scan is arranged at the position 20c by a phased array probe. The path to the defect is further shortened, and the reliability of defect identification is improved with respect to a void which is a minute internal defect than in the case of the electronic scan with the transverse wave oblique angle. In other words, the detectability is improved by using cracked defects (lateral waves) at an oblique angle and spherical defects (vertical waves) vertically. In addition, in the case of an electronic scan with a shear wave oblique angle, an ultrasonic reflection echo may not be obtained at the delamination part. Also, the reliability of defect identification is improved.

  FIG. 14 shows a sectional view when no back wave is generated, and FIG. 16 shows a display screen of the flaw detection result. FIG. 16 shows a cross-sectional shape diagram 47 of the site to be examined, a depth cursor 43, a reflected echo position, and the like. First, the probe is placed at the position 20a in FIG. 14A, and the bottom surface 8 is detected by vertical wave vertical inspection. The depth cursor 43 is made to coincide with the display depth of the bottom echo 51. Next, the probe is arranged at a position 20b in FIG. 14B, and the inside of the weld is electronically scanned with a longitudinal wave. On the screen shown in FIG. 15, it is confirmed whether the display depths of the echoes 52p and 50p from the shape 3 and the depth of the cursor 43 match. FIG. 16 shows an example in which both are the same and correction is not necessary. However, if they are not the same, the sound velocity / refraction angle of the ultrasonic wave is corrected as in the first embodiment, and the depth of both is corrected. Add steps to match. Finally, in a state where the probe is combined with the shoe 22, the probe is arranged at a position 20c in FIG. 14C, and the vicinity of the bottom of the welded portion is electronically scanned with a transverse wave oblique angle. On the screen shown in FIG. 16, it is confirmed whether the display depth of the echo 52 from the shape 3 matches the depth of the cursor 43. FIG. 15 shows an example in which both are the same and correction is not necessary. However, if they are not the same, the sound velocity / refraction angle of the ultrasonic wave is corrected and the depth of both is corrected as in the first embodiment. Add steps to match. FIG. 16 shows the depths of the bottom surface echo 51 and the echoes 52, 52p, and 50p from the shape 3 in which all the flaw detection results of FIGS. 13 (A), (B), and (C) described above are displayed. It must match, the echoes 54 and 54p match the bottom surface depth, so that it can be determined as an echo of a groove unwelded portion, and the echoes 55 and 55p are located shallower than the bottom surface, so that they should be determined as defect echoes Can be confirmed.

  With the above configuration, in the ultrasonic inspection of the welded portion, the relative position between the bottom surface of the object to be inspected and the depth of the reflected echo can be accurately compared even when the ultrasonic wave may not go straight when passing through the welded portion. Therefore, the back wave echo of the welded part and the echo other than the back wave (echo from the groove unwelded part, defect echo) can be reliably identified. In addition, the detectability is improved by using the longitudinal wave and the transverse wave separately for the vertical flaw detection and the oblique flaw detection. Moreover, the reliability of defect identification with respect to voids, which are minute internal defects, is improved by electronic scanning of the welded portion with longitudinal waves. In addition, the reliability of defect identification is improved for delamination defects.

DESCRIPTION OF SYMBOLS 1 Inspected object 2 Base material 3 Shape (it becomes a reflection source of an ultrasonic wave) 4 Welding part 5 Back wave 7 Welding groove 7a Groove welding part 7b Groove unwelded part 8 Bottom face 10 Defect 11 Single array probe 12 Single array flaw detectors 20, 20a, 20b, 20c, 21 Phased array probe 22 Shoe 23 Phased array flaw detector 24 Flaw detection condition setting / signal processing device 25 Display 70 Welding rotor 85 Storage unit

Claims (13)

An ultrasonic inspection method for a welded portion of an object to be inspected formed from a base material and a welded portion that joins the base material , wherein the base material has a bottom surface near the welded portion that is deeper than a bottom surface other than the vicinity of the welded portion. A portion formed by a base material from the surface of the base material to the bottom surface near the welded portion, the surface of the base material and the bottom surface near the welded portion being substantially parallel, and the welding Of the welded part of the object to be inspected having a shape part formed on the base material that is reflected at the oblique angle from the surface of the base material and located at the same depth as the bottom surface near the base part In the inspection method,
The bottom surface depth calculation result in the vicinity of the welded portion calculated by the vertical flaw detection method for the portion formed by the base material, and the oblique flaw detection method from the base material surface to the shape portion through the base material and the welded portion When the bottom surface depth calculation result in the vicinity of the weld calculated in step 1 is compared, and it can be confirmed that the result matches,
An ultrasonic inspection method for a welded portion, wherein the depth of a bottom surface near the welded portion of the object to be inspected is compared with the depth of a reflected echo image of ultrasonic waves to identify the reflected echo. In the ultrasonic inspection method for welds according to claim 1,
The bottom surface depth calculation result in the vicinity of the welded portion calculated by the vertical flaw detection method for the portion formed by the base material, and the oblique flaw detection method from the base material surface to the shape portion through the base material and the welded portion When the bottom surface depth calculation result near the weld calculated in step 1 is compared, and the result does not match,
It said bottom surface depth of weld near calculated in oblique flaw detection method is corrected sound velocity and refractive angle of the oblique flaw detection method to match the bottom depth of the weld vicinity calculated in the vertical flaw detection method in addition,
An ultrasonic inspection method for a welded portion, wherein a depth of a reflected echo image of the ultrasonic wave is calculated using the corrected sound velocity and refraction angle. In the ultrasonic inspection method for welds according to any one of claims 1 to 2,
Identification of the echo, the depth of the reflection echo image is determined to shape echo from the back wave when in the position deeper than the bottom surface of the weld vicinity, the depth of the reflection echo image for the bottom of the weld vicinity If the depth of the reflection echo image is shallower than the bottom surface in the vicinity of the welded portion , the defect echo from the defect located in the welded portion is determined. An ultrasonic inspection method for a welded portion, characterized in that: In the ultrasonic inspection method of the welding part according to any one of claims 1 to 3,
An ultrasonic inspection method for a welded portion, wherein longitudinal ultrasonic waves are used for the vertical flaw detection method, and transverse wave ultrasonic waves are used for the oblique flaw detection method. In the ultrasonic inspection method of the welding part according to any one of claims 1 to 4,
The bottom surface depth calculation result in the vicinity of the welded portion calculated by the vertical flaw detection method for the portion formed of the base material, and the electronic scanning is performed from the surface of the welded portion to the shape portion through the base material and the welded portion. When the bottom surface depth calculation result in the vicinity of the calculated weld is compared and it can be confirmed that the result matches,
When the reflection echo image is detected at a position where the depth of the echo reflection image of the ultrasonic wave by the electronic scan is shallower than the bottom surface depth in the vicinity of the weld, it is determined as a defect echo from the defect located in the weld. A characteristic ultrasonic inspection method for welds. In the ultrasonic inspection method of the welding part according to any one of claims 1 to 5,
The bottom surface depth calculation result in the vicinity of the welded portion calculated by the vertical flaw detection method for the portion formed of the base material, and the electronic scanning is performed from the surface of the welded portion to the shape portion through the base material and the welded portion. Compare the calculated bottom depth calculation results near the weld, and if the results do not match,
The correction speed of sound and the refraction of the electron scanning as the bottom depth of the weld vicinity calculated by the electronic scanning is coincident with the bottom surface depth of the weld vicinity calculated in the vertical flaw detection method in addition,
An ultrasonic inspection method for a welded portion, wherein a depth of a reflected echo image of the ultrasonic wave is calculated using the corrected sound velocity and refraction angle. In the ultrasonic inspection method of the welding part according to claim 6,
An ultrasonic inspection method for a welded portion, wherein longitudinal scanning ultrasonic waves are used for the electronic scan. In the ultrasonic inspection method of the welding part according to any one of claims 1 to 7,
The ultrasonic inspection method for a welded portion, wherein the object to be inspected is a welding rotor. In the ultrasonic inspection method of the welding part according to any one of claims 1 to 8,
The inspected object is a welded rotor, and has an obstacle for ultrasonic flaw detection of a turbine wheel and a packing groove on one of the base materials, and a welded portion capable of oblique flaw detection only from the other side of the base material Ultrasonic inspection method. An ultrasonic inspection apparatus for a welded portion of a test object formed from a base material and a welded portion that joins the base material , wherein the base material has a bottom surface near the welded portion that is deeper than a bottom surface other than the vicinity of the welded portion. A portion formed by a base material from the surface of the base material to the bottom surface near the welded portion, the surface of the base material and the bottom surface near the welded portion being substantially parallel, and the welding Of the welded part of the object to be inspected having a shape part formed on the base material that is reflected at the oblique angle from the surface of the base material and located at the same depth as the bottom surface near the base part In inspection equipment,
A first probe that transmits and receives ultrasonic waves to a portion formed of the base material;
A first ultrasonic flaw detector for driving the first probe;
First display means for displaying an ultrasonic flaw detection result of the ultrasonic flaw detector;
A path length calculating means for calculating a depth of a reflected echo image of an ultrasonic wave received by the probe and displaying the depth on the first display means;
A second probe that transmits and receives ultrasonic waves at an oblique angle from the base material surface to the shape part through the base material and the welded part;
A second ultrasonic flaw detector for driving the second probe;
An echo image calculating means for recalculating the depth of the echo image by correcting the sound velocity and the refraction angle of the ultrasonic flaw detection result of the second flaw detector;
And a second display means for displaying the processing result of the echo image calculating means. In the ultrasonic inspection apparatus of the welding part according to claim 10,
The first ultrasonic flaw detector for causing the first probe to drive longitudinal ultrasonic waves;
An ultrasonic inspection apparatus for a welded portion, comprising: the second ultrasonic flaw detector that drives the second probe to generate ultrasonic waves of transverse waves. An ultrasonic inspection apparatus for a welded portion of a test object formed from a base material and a welded portion that joins the base material , wherein the base material has a bottom surface near the welded portion that is deeper than a bottom surface other than the vicinity of the welded portion. A portion formed by a base material from the surface of the base material to the bottom surface near the welded portion, the surface of the base material and the bottom surface near the welded portion being substantially parallel, and the welding Of the welded part of the object to be inspected having a shape part formed on the base material that is reflected at the oblique angle from the surface of the base material and located at the same depth as the bottom surface near the base part In inspection equipment,
A phased array probe that transmits and receives ultrasound;
A phased array ultrasonic flaw detector for driving the phased array probe;
A path length calculating means for calculating a depth of an ultrasonic echo image of an ultrasonic flaw detection result from the phased array flaw detector;
An echo image calculating means for correcting the sound velocity and the refraction angle of the ultrasonic echo image and recalculating the depth of the echo image;
An ultrasonic inspection apparatus for a welded portion, comprising: display means for displaying a processing result of the echo image calculation means. In the ultrasonic inspection apparatus for welds according to claim 12,
It has a phased array flaw detector that drives the phased array flaw detector to drive longitudinal wave ultrasonic waves during vertical flaw detection and transverse wave ultrasonic waves during oblique flaw detection. Sonographic equipment.