JPS62115361A - Ultrasonic flaw detecting device - Google Patents

Abstract

PURPOSE:To measure the size of a defect at the fitting parts of a turbine disk key groove part and a bore part by making an ultrasonic wave beam from each transmitting probe incident on the tip of the defect and receiving an end part echo by receiving probes on the same side with the defect and on the opposite side. CONSTITUTION:Ultrasonic probes 10a, 10b, 10a', and 10b' provided on the hub 3 of a turbine disk are movable by scanners 11a, 11b, 11a' and 11b'; the probes 10a and 10b are used for transmission and the probes 10a' and 10b' are used for reception. A CPU 14 controls the excitation and reception timing of the probes electronically so as to receive an ultrasonic beam incident from one of the probes 10a and 10b by two probes 10a' and 10b' sequentially and also switches in-use probes. A position detector 18 detects the position of a probe on the hub 3 and sends data to a memory 19, and a signal processor 16 processes and sends received ultrasonic waveform data to the memory 19. An arithmetic processor 20 calculates the size of the defect by using the detected probe position, detected ultrasonic beam course, and information on the shape of the object, and displays the size on a CRT 21.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a turbine disk in which the object to be inspected has a flange protruding from the upper surface of the base portion approximately at the center thereof, and a rotor in the turbine disk. Detecting defects that occur in a planar manner along the axial direction of the rotor shaft in the key groove portion of the fitting surface with the shaft (corresponding to the root of the flange in the base portion), and measuring the dimensions and shape of the planar defects. This article relates to an ultrasonic flaw detection device.

[Technical Background of the Invention and Problems thereof]] Fig. 6 shows a conventional case where a keyway portion of a fitting surface with a rotor shaft of a turbine disk is searched as an object to be inspected. ) is a perspective view thereof, and FIG. 6(b) is a view seen from the rotor axial direction.

As shown in the figure, an ultrasonic angle probe 6 is installed on the hub 3 of the turbine disk 1, and an ultrasonic beam 7 is made incident in the direction of the defect 5 to produce defect edge echoes 8 and defect corner echoes 9.
The defect size is measured using the beam path of each echo.

However, with this method, when the probe position changes from Pt - to pn - as shown in Fig. 7, an end echo from the big end tip and a noise echo caused by the turbine disk material etc. are generated as shown in Fig. 8. The S/N ratio becomes very poor, and therefore,
It is difficult to separate and detect edge echoes. Therefore, there was a problem in that it was very difficult to measure the defect size.

[Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to examine, for example, a turbine disk key groove portion as an object having a flange protruding from the longitudinal center of the upper surface of the base portion. Another object of the present invention is to provide an ultrasonic imaging device capable of measuring the size of defects occurring in the fitting portion of a bore portion, especially defects in wear portions.

[Summary of the Invention] In order to achieve the above object, the present invention provides a test object having a flange protruding from the upper surface of the base part in the longitudinal direction substantially at the central part thereof. Two transmitting probes are installed on one side, and two receiving probes are installed on the other side. Ultrasonic beams from two transmitting probes are made incident on the defective tip, and the end echoes generated at the tip are received by receiving probes on the same and opposite sides of the defect, and these probes are held. The end echo is detected in the same way at each probe position by moving the drive device in synchronization. In this way, the ultrasonic waveform data including the end echoes obtained for each probe is subjected to signal processing and analytical calculation processing to measure the defect tip position. Even if there is a decrease in detection sensitivity for edge echoes or a directionality in the appearance of edge echoes, it is possible to detect edge echoes with at least one of the probes, and it is possible to detect edge echoes with both probes. If an end echo is detected in the above, it is possible to perform a defect inspection based on the analysis of both, which makes it possible to measure dimensions with higher accuracy.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1(a) and 1(b) show ultrasonic probes 10a, 10b, 10a', and 10b of this embodiment, respectively.
- is an axial sectional view and a top view when installed on the same axis on the hub 3 sandwiching the web 2 of the turbine disk 1.

In FIG. 1(b), the scanner <drive device 11a
, 11b, 11a'', 11b - ultrasonic probe 1
0a, 10b, 10a +, iob - are for transmitting and receiving ultrasonic probes 10a, 10b, ultrasonic probes 10a-,
10b- is used as a receiving probe, and each probe has the same refraction angle β and the same head angle θ.

Ultrasonic beam 12a incident from ultrasonic probe 10a
causes mode conversion at the tip of the defect in the web portion 2, and is diffused in various directions as diffracted waves. At this time, the probe 10a
+, 10b' end echo 12a +, 12b'
Detect. Next, the end echoes 12a and 12b of the ultrasonic beam 12b incident from the probe 10b are detected by the probes 10a and 10b, as described above.

Here, as shown in FIGS. 2(a) and 2(b), a transmitting probe is installed at a position Pa on one hub 3 sandwiching the web 2 of the turbine disk 1, and a transmitting probe is installed at a position Pa on the other hub 3. When the receiving probe is installed at = and the ultrasonic beam is incident from Pa, the S/N ratio of the receiving sensitivity of the detected end echo at the receiving probe position Pr-ppm is examined. As shown in Figure (C), the probe positions P1 and pn where the neck angle of the receiving probe matches the neck angle of the transmitting probe
It has been experimentally confirmed that the S/N ratio is the highest when

Now, in FIG. 1(b), each probe 10a, 10b, 10a', 10b- installed on the hub 3 is scanned by each scanner 11a, 11b, 11a'', 11b- in the circumferential direction on the hub 3. The central part of the keyway 4 detected in advance is set to the coordinate origin 0 (x, y, z) of the measurement system.
and the probe 10a from that axis.

10a- is S! In the direction, the probes 10b, 10b- are S2
The probes 10a and 1
For the ultrasound beam transmitted from 0b, probe lQ
The waveform data received at a', 10t)- is treated as one data group and a total of four types of data groups.

FIG. 3 is a block diagram showing the configuration of the apparatus of this embodiment. In the figure, a CPU 14 such as a microcomputer
A signal for controlling ultrasonic excitation and reception timing is sent to the pulser/receiver group 13, and each pulser in the pulser/receiver group transmits a high voltage pulse for ultrasonic generation to the probes 10a, 10b. At the same time, a pulse for ultrasonic reception is also applied to the reception probes 11a' and 11b-. The four types of ultrasonic signals received by the receivers in the same pulser/receiver group are
Each signal undergoes high-speed A/D conversion via the A/D converter 15 and is sent to the signal processor 16.

Further, the CPU 14 controls a scanner controller 17, and a scanner 11a having a built-in probe.

11b, 11a', 11b- are scanned at a predetermined moving pitch and moving speed, and the probe position information obtained by transmitting and receiving ultrasonic waves is controlled to be output to the position detector 18. Now, the signal processor 16 performs peak detection of each echo, measurement of beam path data, addition processing for noise processing, etc. on the received ultrasonic waveform data, and stores each of the four types of data groups in the memory 19. The data is sent, position information obtained by the position detector 18 is added, and the arithmetic processor 2 is controlled by the CPU 14.
Sent to 0. The arithmetic processor 20 extracts the end echo data group, that is, the end echo beam path value and the probe position data group, according to preset analysis conditions from the echo data processed by the signal processor 16. The defect end position is calculated by substituting into the following equation (1). This process is performed for each of the four types of data groups.

(X O−Xi) 2+yi+ (Z Q −Zf)
2-Jl'l 2(z a -zz) 2+yj+ (
z o −zz) 2−Jlj 2・・・・・・(1) Here (x+, y+, zi), (Xj, y
j+ zz) is the coordinate of the probe position as 1. ! i, fj are
It is the beam path value of the edge echo detected at that time, and (×a.

20) indicates the defect tip coordinates.

The position of the calculated defect coordinates is located on the key groove 4 which is displayed as an image in advance, and the defect size is measured as the distance from the defect tip position to the key groove and output to a printer.

In this way, the end echo, which is a diffracted wave that is transmitted from one probe and mode-converted at the tip of the defect, is transmitted to the defect by the receiving probe installed on the hub on the same side and on the opposite side of the transmitting probe. Since the end echo is detected by at least one of the receiving probes, regardless of the characteristics such as the tilt of the defect, and if the end echo is detected by both probes, the By superimposing the analysis results using the data, it becomes possible to reliably and precisely measure the defect size.

FIG. 4 is an example of a display where the defect position is located by the apparatus of this embodiment, and the defect shown in FIG. 4(a) is displayed as shown in FIG. 4(b).

Further, as shown in FIG. 5(a) and (b), the scanner 1
1a to 11b' while scanning in a zigzag manner and performing edge echo detection, signal processing, and arithmetic processing in the same manner as described above, it is possible to detect flaws in the entire web section, and the defect position control point 23 can be detected. The defect shape can also be measured.

[Effects of the Invention] As described above, according to the present invention, a rotating body pressure section, for example, a turbine disk and a rotor shaft, is used as the test object having a flange protruding from the longitudinal center of the upper surface of the base. For surface defects along the rotor axial direction that occur in the key groove and bore of the fitting part with the
Install a transmitting probe on one side and a receiving probe on the other side on both sides of the hub that sandwich the turbine disk web, synchronize all the probes, and place them on the right and left sides of the keyway. The installed probes repeatedly transmit and receive ultrasonic waves while scanning in opposite directions to detect defective echoes.

These probe scanning and flaw detection timings are controlled by electrical signals from a computer. Here, since the transmission from one ultrasonic contactor is received by two reception probes and there are 2aI transmission probes, data for four types of reception echoes are focused. In addition, all the probes were set to have the same refraction angle and neck angle, which were calculated in advance, so that the end echo from the tip of the defect could be detected with high sensitivity. The received ultrasonic waveform data is processed by a signal processor and an arithmetic processor to extract a data group of defect edge echoes and calculate the defect tip position through analysis processing to measure the defect size. In this way, defect dimensions can be measured for one defect by signal processing using up to four types of data, and defect detection and dimension measurement can be performed reliably and with high precision. moreover,
By performing waveform data collection, signal processing, and dimension measurement in the same manner as described above while scanning in a zigzag manner with the driving device (scanner) that holds each probe, it is also possible to measure the shape of defects in the web portion.

Therefore, if the above-described probe scanning and reception method is used, the edge echo from the tip of the defect can be detected with good sensitivity at at least one of the four reception positions, and the defect size and shape can be measured and detected. It is possible to provide an ultrasonic flaw detection device that can perform measurements and significantly improve the reliability of ultrasonic flaw detection in maintenance and inspection of turbine disks.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a flaw detection method according to an embodiment of the present invention, Fig. 2 is a schematic diagram showing a state of detecting edge echoes for deriving an embodiment of the present invention, and Fig. 3 is an explanatory diagram showing a flaw detection method according to an embodiment of the present invention. A configuration diagram showing one embodiment of the present invention, FIG. 4 is an image display diagram according to an embodiment of the device of the present invention, and FIG. 5 is an explanatory diagram showing another embodiment of the present invention.
FIGS. 6 to 8 are diagrams for explaining conventional examples, respectively. 1... Turbine disk, 2... Web, 3...
Hub, 4...Keyway, 5...Defect, 10a-10b
'...Haki sonic probe, 11a-11b'...Scanner, 12a-12b-...Ultrasonic beam, 13...
・Pulser/receiver group, 14...CPU, 15・
... A/D converter, 16... Signal processor, 17...
Scanner controller, 18... position detector, 19
...Memory, 20...Arithmetic processor, 21...C
RT, 22... Printer, 23-... Defect position control point, Pt~pn, pl~Pn'', Pa... Ultrasonic probe position, St, 32... Probe scanning direction , θ, θ1~θn... neck angle, β... refraction angle, J
1-J4...Zigzag scanning. Applicant's agent Patent attorney Takehiko Suzue Figure 1 (1)) Figure 5 (a) % Figure 5 (b) Figure 6 (b)

Claims (1)

[Claims] In an ultrasonic flaw detection apparatus that performs ultrasonic flaw detection on the base portion of the base portion of the test object, the collar portion of which is protruding from approximately the center in the longitudinal direction of the upper surface of the base portion, Four ultrasonic probes with symmetrical swing angles, facing toward the flange, and having the same refraction angle are installed on both sides of the base sandwiching the flange. Two probes are used for transmitting on one side, and two probes are used for receiving on the other base part, so that two receiving probes are used for each ultrasonic beam incident from one transmitting probe. A control device capable of electronically controlling the excitation and reception timing of the probe and switching the probe to be used so that the ultrasonic probe receives signals sequentially; and a control device that can arbitrarily select the ultrasound probe. a drive device driven at a scanning speed and scanning method;
a position detector that detects the position of the probe on the base portion; a signal processor that processes the ultrasonic signal detected by the ultrasonic transmission and reception of the probe; Ultrasonic flaw detection characterized by comprising an arithmetic processor that calculates defect dimensions using information on the ultrasonic beam path and the shape of the object detected through signal processing, and an image display that displays an image of the defect position. Device.