JP3609975B2 - Sizing ultrasonic flaw detector and sizing flaw detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic scanning ultrasonic inspection apparatus and method for nondestructively inspecting the internal state of a subject such as a welded portion by using ultrasonic waves, and in particular, the type of flaws formed inside the subject. And an electronic scanning ultrasonic inspection apparatus and method suitable for evaluating the size.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 11-14611 discloses an arc array type transmitting array probe and a receiving array probe, and these array probes are moved in parallel along a test portion while maintaining a predetermined interval. A mechanical scanner that transmits an ultrasonic beam having a sharp directivity from the transmission array probe in a fan shape, and a reflected wave signal from a test portion detected by the reception array probe A circuit unit that sequentially stores the required addresses on the frame memory in accordance with the position signals of the array probes detected by the encoders attached to the encoder, and the reflected wave signals stored in the frame memory in real time. An image display unit for displaying as an image based on three-dimensional information, and the beam directing regions of the transmitting array probe and the receiving array probe at each time point during the sector scan intersect the circuit unit. An electronic scanning ultrasonic inspection apparatus provided with delay time adjusting means for adjusting directivity so as to focus an ultrasonic beam at a certain position is described.
[0003]
An ultrasonic flaw detector for sizing using the TOFD (TIME OF LIGHT DEFFRACTION) method will be described. The TOFD method is defined in the British standard BS7706 (1993). Ultrasound is transmitted from the fixed angle probe for transmission, and the diffracted wave from the defect is received by the fixed angle probe for reception. While holding the transmission / reception probe at a constant interval, a position signal from a scanner that moves the entire probe in the horizontal direction X under the control of the control device and an ultrasonic signal from the ultrasonic flaw detector are input, respectively. It is composed of a data recording processing device that performs TOFD processing. In the data recording processing apparatus, the horizontal axis represents the distance traveled by the probe, the vertical axis represents the ultrasonic wave propagation time, the display of the diffracted wave is confirmed, and the dimension of the defect is obtained. In this TOFD method, it is necessary to appropriately enter ultrasonic waves and receive diffracted waves with respect to the defect to be sized. Generally, the ultrasonic waves are incident from the direction of 45 to 55 degrees, and the opposite. It is necessary to receive from the direction of 45 degrees to 55 degrees. The probe for transmission and reception is designed to obtain a diffracted wave from each part of the defect by increasing the beam spread compared to a normal probe. However, depending on the depth and shape of the defect to be sized, the beam spreads. As a result, it is necessary to selectively replace a probe having an optimum flaw detection angle each time for a defect in which a diffracted wave from the edge of the defect may not be obtained, or a defect in which a diffracted wave is difficult to obtain. In addition, the intensity of the diffracted wave itself may be weakened due to the spread of the beam, which has been a factor in reducing defect detectability.
[0004]
[Problems to be solved by the invention]
The present invention reduces the time for selecting the flaw detection angle during flaw detection by the TOFD method, and even if the depth of the defect and the plate thickness of the object to be inspected are changed, the probe does not need to be replaced with a simple setting. It is another object of the present invention to provide an ultrasonic flaw detection apparatus and method which can employ a TOFD flaw detection method with improved defect detection.
[0005]
[Means for Solving the Problems]
The present invention relates to a sizing flaw detection method in which an ultrasonic beam is applied to a defect in a test portion, and a propagation time of the obtained diffracted wave is measured to display the defect.
And transmitted from the transmitting electronic scanning array probe ultrasonic beam focal position location flaw detection angle and depth as a variable is more controlled in phase matching defects the test unit, the phase by the reception electronics scan array probe diffracted wave The received and transmitted focal positions as the inspection positions are sequentially moved to set the defect end as the focal position, the intensity of the diffracted wave at the focal position is increased, and the superpositions obtained at the N focal positions are obtained. Storing ultrasonic waveform information, synthesizing and storing one-line ultrasonic waveform information based on ultrasonic waveform information about the focal point of N points, and synthesizing and storing a plurality of one-line ultrasonic waveform information; Based on the stored ultrasonic waveform information, ultrasonic waveform information indicating a defect is displayed as an image.
[0006]
Specifically, the present invention relates to an ultrasonic flaw detector for sizing in which an ultrasonic beam is applied to a defect in a test portion, and a propagation time of the obtained diffracted wave is measured and the defect is displayed on a display device. Phase matching of the diffracted wave emitted from the defect of the inspection part and the transmission electron scan array probe for emitting the ultrasonic beam in which the flaw detection angle and the focal position where the depth is changed are controlled by phase matching. And a receiving electronic scan array probe for receiving in a predetermined interval, and a scanner for translating the transmitting and receiving electronic scan array probes along the test portion at the predetermined interval. An N-focus memory for storing ultrasonic waveform information obtained at N focal positions, and information obtained by synthesizing one-line ultrasonic waveform information based on the ultrasonic waveform information stored in the N-focus memory. A multi-line synthesized ultrasound waveform information is stored in the frame memory based on the 1-line synthesized ultrasound waveform information stored in the plurality of 1-line synthesized focus memories. Provided is a sizing ultrasonic flaw detector for imaging defect display ultrasonic waveform information as shades based on the multi-line synthesized ultrasonic waveform information.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment according to the present invention will be described below with reference to the drawings.
[0008]
FIG. 1 shows a schematic configuration of an embodiment of the present invention. The electronic scan probe 1 (1a, 1b) is used for the probe. An ultrasonic wave is transmitted from the electronic scan probe 1a to the inspection object 6, and a diffracted wave from the defect 7 (7a, 7b) is received by the electronic scan probe 1b. While holding the electronic scan probes 1a and 1b at a constant interval, the electronic scan probes 1a and 1b are moved in the horizontal direction X by the probe scanner 3 under the control of the control device 4, and the position signal from the flaw detector scanner 3 is data. Input to the recording processing device 5. The electronic scan controller 2 amplifies transmission / reception of ultrasonic waves by control, and inputs the ultrasonic signals received after being diffracted to the data recording processing device 5. The data recording processing device 5 uses the obtained signal, performs TOFD processing as described later, the horizontal axis represents the movement distance of the electronic scan probes 1a and 1b, and the vertical axis represents the ultrasonic wave propagation time. Is displayed on the screen of the image device, and the position and size of the defect are obtained.
[0009]
The electronic scan controller 2 controls the flaw detection angle and the focal length by phase matching. As a result, an optimum beam is selected from the directional beams with respect to the defect 7, ultrasonic waves are transmitted by the electronic scan probes 1 a and 1 b, and diffracted waves can be received. Depending on the fixed angle probe, it is possible to sequentially change the flaw detection angle for the defect 7a for which it is difficult to receive the diffracted wave, so that the optimum transmission / reception at the optimum flaw detection angle becomes possible.
[0010]
In this case, the focal point is sequentially focused in the depth direction of the inspected object 6, the ultrasonic wave is converged on the edge of the defect, and the TOFD process is performed with the propagation time (also referred to as a propagation path length) of the diffracted wave at the combined focus. Can reliably capture diffracted waves.
[0011]
FIG. 2 shows a method for setting the focus of the electronic scan probe. In general, between the transmission electronic scan probe 1a and the reception electronic scan probe 1b, transmission / reception ultrasonic characteristics are sequentially set on the defective line 10a to be inspected at an intermediate position of transmission / reception as a focal position. by going defects 7a, the focus is moved to 7b, which makes it possible to enhance the intensity of the diffracted wave from the defect ends.
[0012]
FIG. 3 shows an ultrasonic waveform obtained when the focal point moves as described above, and echoes in the focal ranges 10d and 10e in the focused portion can be selected.
[0013]
FIG. 4 is a block diagram showing the configuration of the embodiment. In the figure, a transmission delay control circuit 21 and a reception delay control circuit 22 are controlled by an electronic scan controller 2, and a signal delayed from a pulsar circuit switch 23 is transmitted from each ultrasonic vibration element of the electronic scan probe 1a to an object to be inspected 6. To do. The diffracted wave is received by each ultrasonic vibration element of the electronic scan probe 1 b and sent to the reception delay circuit 25 via the preamplifier switch 24. Signals diffracted for each scan are added by an adder 26, A / D converted by an A / D converter 27, and sent to a focus memory 28. The focus memory 28 is composed of N elements from a 1-focus memory to an N-focus memory, and stores a reception signal on the defect line 10a aligned with one focus. Here, the focusing method to the focus will be described.
[0014]
First, FIG. 5 shows a method of focusing an ultrasonic wave at an arbitrary point.
[0015]
In order to focus and transmit ultrasonic waves to an arbitrary depth of an inspection object (steel material), an arbitrary chord group (7 elements / group in the figure) in the transducer element group arranged in an arc shape is used. When an ultrasonic wave is transmitted simultaneously from each element, it propagates as indicated by the dotted line due to the interference of the ultrasonic wave, and focuses on the center of curvature 0a of the arc aa ′ plane in which each element is arranged. That is, by giving a delay time (Δt) by a delay line provided for each cord, a time delay corresponding to Δt is generated in the transmission pulse, so that the ultrasonic wave transmitted by each element is as if the arc bb ′. It propagates as it is transmitted from the surface and converges at the reflector 0b. In the reception shown in FIG. 5A, the reception side reflects the ultrasonic wave at the point 0 ′, and receives the time difference (phase difference) by each cord on the reception side. Therefore, by setting a delay time similar to that at the time of transmission, the phases of the received signals are made uniform and synthesized into one signal by an adder. As a result, the intensity of the diffracted wave at the focal position can be increased.
[0016]
Next, a method for controlling the incident angle of ultrasonic waves is shown in FIG.
[0017]
As shown in FIG. 6, if the number of elements necessary for the ultrasonic bundle is always set as one set from the transducer cord group, for example, (1), (2), and (3) are sequentially shifted for each element. The incident angle of the ultrasonic waves changes as θip, 2θip, 3θip,... Corresponding to the arrangement pitch of the elements. Therefore, the ultrasonic wave diffracted at the refraction angle based on the incident angle enters the object to be inspected.
[0018]
As described above, in the electronic scanning method, by giving a delay time to the transducer cord group, the ultrasonic wave is focused on an arbitrary position of the object to be inspected, and the element group to be transmitted and received is sequentially switched to change an arbitrary angle (variable). (Square) flaw detection is possible.
[0019]
The electronic scan controller 2 includes a focus setting position setting unit that sequentially moves the focal position as the inspection position and sets the defect end as the focal position, and a diffracted wave intensity setting unit that increases the intensity of the diffracted wave at the focal position. And provide.
[0020]
Returning to FIG. 4, one-line propagation time synthesis is performed based on the propagation time information stored in the N focus memories of the focus memory 28.
[0021]
As shown in FIG. 7, the echo obtained in this focal range is sequentially synthesized with 10d and 10e in the form of a TOFD processing screen, thereby changing the propagation time due to the spread of the ultrasonic beam obtained by the conventional TOFD method. An ultrasonic flaw detector for sizing using the TOFD method, which can be obtained in the same manner in a form where the intensity of the ultrasonic beam is increased for each depth of the figure and the defect detectability is improved, can be realized.
[0022]
Storing one line ultrasonic waveform information into a line synthesis focal memory 29 based on the ultrasound waveform information stored in the N focal memory. A plurality of one-line synthetic focus memories are provided. Based on the one-line synthetic ultrasonic waveform information stored in the plurality of one-line synthetic focus memories 29 and the horizontal movement amount X of the probe scanner 3. The multi-line synthesized ultrasonic waveform is stored in the frame memory 30. In the multi-line synthesis, a command for moving the probe scanner 3 in the horizontal direction is given by the electronic scan controller 2, and the coordinate position is measured by the coordinate generation circuit 32. Based on the stored multi-line synthetic ultrasonic waveform information , an image signal is generated from the defect display ultrasonic waveform information , and the defect is displayed on the image unit 31 (display unit of the image device) by this signal.
[0023]
FIG. 8 shows a step of synthesizing one line propagation time. Defect 7a, defect inspection line 10a, _{P 2} defects lower, upper and _{B 3, P 1} the bottom surface shown in _{P 4.} As shown in (b), when setting the focus P ₁ is, appear larger diffracted wave signals P _1, this signal is input as a gate signal P _11. Bring sequentially focus on, as shown in (b), when setting the focal point P _2, diffracted wave signal is intensified diffraction intensity appears larger diffracted wave signal P _2. Be extracted ultrasound waveform of the focus position by the gate signal P _21, it is possible to extract only the ultrasonic diffraction intensity is strengthened.
[0024]
Furthermore, as shown in focus are listed above (c), when setting the focus on P _3, it appears larger diffracted wave signal P _3. In this case, it is possible to retrieve only ultrasonic waveform diffraction intensity is strengthened by the gate signal P _31. Can be taken out ultrasonic wave surface by the focus is set to the surface gate signal P _41.
[0025]
By synthesizing the diffraction signals thus produced, a one-line ultrasonic waveform as shown in (e) is created and stored in the one-line focus synthesis memory 29. The processing after the storage is as described above.
[0026]
【The invention's effect】
According to the present invention, by using one set of electronic scan array probes, sizing of defects having different depths can be detected using the TOFD method at an optimum angle. Further, by moving the focal point, it is possible to enhance the diffracted wave from the defect end and improve the defect detectability.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a sizing apparatus based on a TOFD method using an electronic scan probe according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram of focus movement.
FIG. 3 is an explanatory diagram of a focus range and a detection echo when a focus is moved.
FIG. 4 is a block diagram showing an embodiment of the present invention.
FIG. 5 is an explanatory diagram of beam focusing.
FIG. 6 is an explanatory diagram of an electronic scan fan-shaped scan.
FIG. 7 is an explanatory diagram of a TOFD screen display method during focus movement.
FIG. 8 is a one-line ultrasonic waveform synthesis step diagram.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1a ... Electronic scan probe for transmission, 1b ... Electronic scan probe for reception, 2 ... Electronic scan controller, 3 ... Probe scanner, 4 ... Control apparatus, 5 ... Data recording processing apparatus, 6 ... Test object, 7a, 7b Defect, 8 ... Ultrasonic flaw detector, 9a ... Fixed angle probe for transmission, 9b ... Fixed angle probe for reception, 10a ... Defect inspection line, 10b, 10c ... Convergent ultrasonic beam, 10d, 10e ... Focus range.

Claims (2)

In the ultrasonic flaw detector for sizing in which the ultrasonic beam is applied to the defect of the test part, the propagation time of the obtained diffracted wave is measured, and the defect is displayed on the display device.
A phase-matching of an electron scanning array probe for transmitting an ultrasonic beam, in which the flaw detection angle to be varied and a focal position with a changed depth are controlled by phase matching, and a diffracted wave emitted from a defect in the test part A receiving electronic scan array probe for receiving is disposed at a predetermined interval, and a scanner for translating the transmission and reception electronic scan array probes along the test portion at the predetermined interval is provided,
A transmitting and receiving electronic scan controller to sequentially move the reception focal position as the inspection position to set the defective end portion as the focus position, the gate signal input means for taking out diffracted wave generated at the focal point position provided ,
An N-focus memory is provided for storing ultrasonic waveform information obtained at the N focal positions that are sequentially moved, and one-line ultrasonic waveform information is synthesized based on the ultrasonic waveform information stored in the N-focus memory. 1 line synthetic focus memory for storing and storing multi-line synthetic ultrasonic waveform information in the frame memory based on the one line synthetic ultrasonic waveform information stored in a plurality of one line synthetic focus memories,
An ultrasonic flaw detector for sizing, wherein a defect display is imaged based on the stored multi-line synthetic ultrasonic waveform information. In a sizing flaw detection method in which an ultrasonic beam is applied to a defect in a part to be examined and the propagation time of the obtained diffracted wave is measured to display the defect.
And transmitted from the transmitting electronic scanning array probe ultrasonic beam focal position location flaw detection angle and depth as a variable is more controlled in phase matching defects the test unit, the phase by the reception electronics scan array probe diffracted wave Receiving in alignment , the transmission / reception focal position as the inspection position is sequentially moved to set the defect end as the focal position, the diffracted wave generated at the focal position is taken out by the gate signal, and the sequentially moved N focal points The ultrasonic waveform information obtained at the position is stored, one line propagation time is synthesized and stored based on the ultrasonic waveform information about the focal point of the N points, and a plurality of one line ultrasonic waveform information is synthesized. An ultrasonic flaw detection method for sizing, characterized in that a defect is image-displayed based on the stored ultrasonic waveform information.

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