JP2008151598A - Ultrasonic flaw detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily decide the flaw detection condition of ultrasonic flaw detection. <P>SOLUTION: This ultrasonic flaw detector is equipped with: a probe 12 equipped with a plurality of vibrators 11 arranged in a two-dimensional state, a vibrator scanning part 21 for selecting at least one vibrator of a plurality of the vibrators 11 as a transmission vibrator, selecting at least one receiving vibrator becoming each of a pair of the transmission vibrators, and successively charging over the transmission vibrator and a detection vibrator; a transmission and reception control part 22 for transmitting an ultrasonic wave to the artificial flaw formed at the specific position in a test piece from a transmission vibrator and detecting the reflected wave reflected from the artificial flaw by a receiving vibrator; and a data recording part 23 for accumulating the electric signal of the reflected electric wave received by the receiving vibrator so as to allow the signal to be associated with the flaw detection condition including the data of the combination of the transmission vibrator and the receiving vibrator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultrasonic flaw detector suitable for use in ultrasonic flaw detection, in particular, ultrasonic flaw detection performed on a welded portion of stainless steel or the like.

  Conventionally, ultrasonic flaw detection is known as a method for nondestructively inspecting defects such as cracks generated inside a welded portion of metal. As such an ultrasonic flaw detection method, there is a phased array method. This is because a plurality of transducers arranged in a row or two-dimensionally (matrix) are individually controlled, and the timing of oscillating each transducer is shifted so that the combined wave of ultrasonic beams emitted from each transducer is obtained. To detect the presence or absence of defects such as cracks in the inspection target location by receiving and analyzing the reflected wave or diffracted wave when this synthesized wave is applied to any inspection target location of the inspection target (For example, refer to JP 2005-148209 A).

However, even if the inspection object is irradiated with the ultrasonic beam in this way, the traveling direction of the synthetic wave is bent due to the anisotropy of the particles of the inspection object, and the reflected wave from the inspection object location cannot be received. There is.
Therefore, conventionally, the optimum ultrasonic flaw detection conditions are determined by the following procedure.

First, a test piece made of the same material as the object to be inspected is created, and a crack having a depth so that the reflected wave of the ultrasonic beam can be reliably received is artificially formed at a predetermined position of the test piece. The formation of the crack is performed, for example, by forming a hole having a depth of about several millimeters at a predetermined position of the test piece.
Subsequently, a probe is installed on the test piece, the position of the vibrator, the angle of the ultrasonic wave incident on the test piece from the vibrator (hereinafter referred to as “incident angle”), and the ultrasonic wave is reflected by the crack and received. The reflected waves when the flaw detection conditions such as the angle (hereinafter referred to as “refracting angle”) are changed are received, and the flaw detection conditions when the S / N ratio of the reflected waves is the highest are determined as the optimum flaw detection conditions. To do. Here, the flaw detection conditions are, for example, the installation position, incident angle, refraction angle, and the like of the vibrator as described above.

After finding the optimum flaw detection conditions for the test piece in this way, next, a test piece made of the same material as the object to be inspected is cracked in the same way as the actual method, that is, a crack due to corrosion is detected. When doing so, a crack is naturally generated by impregnating the test piece with a chemical or the like. Then, an ultrasonic flaw detection is performed on the test piece in which such a natural crack has occurred under the above-described optimum flaw detection conditions, and it is verified whether the crack can be reliably detected. As a result, when the crack cannot be detected, the flaw detection conditions are finely adjusted so that the crack can be detected. When it is confirmed that a crack has been detected, an actual machine inspection is performed according to the flaw detection conditions at this time.
JP 2005-148209 A

However, in the conventional method as described above, since the inspector has to manually change the installation position of the vibrator, the burden on the inspector is large.
In addition, since the test piece has to be created in two stages, there is a problem that it takes time, cost, and cost.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method capable of easily determining flaw detection conditions for ultrasonic flaw detection.

In order to solve the above problems, the present invention employs the following means.
The present invention selects a probe including a plurality of transducers arranged two-dimensionally and at least one of the plurality of transducers as a transmission transducer, and each of the transmission transducers A transducer scanning unit that selects at least one receiving transducer as a pair, and sequentially switches between the transmitting transducer and the transducer to be selected as the receiving transducer, and is formed at a specific position in the test piece. Transmitting and receiving ultrasonic waves from the transmitting vibrator toward the artificial defect and receiving the reflected wave reflected by the artificial defect by the receiving vibrator; and receiving by the receiving vibrator And a data recording unit for storing the reflected wave electrical signal in association with flaw detection conditions including information on the combination of the transmitting transducer and the receiving transducer at that time To provide a wound apparatus.

According to such a configuration, at least one transducer is selected as a transmission transducer from a plurality of transducers arranged two-dimensionally, and a pair of the reception transducer is scanned by the transducer. Selected by department. Subsequently, due to the action of the transmission / reception control unit, an ultrasonic wave is transmitted from the selected transmission transducer to the artificial defect in the test piece, and the reflected wave at this time is received by the reception transducer, and this reflected wave Are recorded in the data recording unit in association with the combination of the transmitting transducer and the receiving transducer.
In this case, since the transmitting transducer and the receiving transducer are sequentially switched by the transducer transmitting section, ultrasonic waves can be automatically transmitted from a plurality of different positions and reflected at a plurality of different positions. Can receive waves. This makes it possible to easily record data of reflected waves under various flaw detection conditions without bothering the inspector.

  In the ultrasonic flaw detection apparatus, the transmission / reception control unit sets at least one of an incident angle of an ultrasonic wave transmitted from the transmitting transducer and a refraction angle of a reflected wave received by the receiving transducer at a predetermined angular interval. It is good also as changing with.

  According to such a configuration, when driving the transmitting transducer and the receiving transducer, the incident angle or the refraction angle can be changed at a predetermined angular interval, so that reflection under more detailed flaw detection conditions is possible. Waves can be recorded.

  The ultrasonic flaw detection apparatus may further include a flaw detection condition determination unit that determines an optimum flaw detection condition by analyzing data accumulated in the data recording unit.

  As described above, by analyzing the reflected wave obtained under a plurality of different flaw detection conditions, and extracting the flaw detection condition when the most preferable reflected wave is obtained, the optimum flaw detection condition can be obtained.

  In the ultrasonic flaw detection apparatus, when performing ultrasonic flaw detection on an inspection object under the flaw detection conditions determined by the flaw detection condition determination unit, the transmission / reception control unit includes the incident angle of the transmission transducer and the reception At least one of the refraction angles of the vibrator for use may be changed at a predetermined angular interval, and the defect may be analyzed based on the reflected wave received at this time.

  According to such a configuration, ultrasonic flaw detection is performed on the inspection object using the optimum flaw detection conditions (the position of the transducer, the incident angle, the refraction angle, etc.) determined by the flaw detection condition determination unit. In this case, the transmission / reception control unit changes at least one of the incident angle of the transmitting vibrator and the refraction angle of the receiving vibrator at a predetermined angular interval. Thereby, even if there is a solid difference between the actual machine and the test piece, it is possible to receive the reflected wave under the optimum conditions in the actual machine. As a result, the flaw detection accuracy can be improved.

  According to the present invention, it is possible to easily determine the flaw detection conditions for ultrasonic flaw detection.

An embodiment of an ultrasonic flaw detector according to the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of the ultrasonic flaw detector according to the present embodiment.
As shown in FIG. 1, the ultrasonic flaw detector 10 includes a probe 12 including a plurality of transducers 11 and a control unit 20 that controls the probe 12.

  In the present embodiment, the vibrators 11 are arranged in a two-dimensional manner. Each vibrator 11 is made of a piezoelectric element, and emits a vibration corresponding to an electric signal and an electric signal corresponding to the vibration received from the outside. These vibrators 11 are both variable in incident angle when transmitting ultrasonic waves and refraction angle when receiving reflected waves. The incident angle and the refraction angle are adjusted by the control unit 20 described later.

The control unit 20 includes a transducer scanning unit 21, a transmission / reception control unit 22, a data recording unit 23, a flaw detection condition determination unit 24, and an analysis unit 25 as main components.
The transducer scanning unit 21 selects at least one transducer 11 among the plurality of transducers 11 arranged in a two-dimensional manner as a transmission transducer and at least one paired with each of the transmission transducers. One receiving transducer is selected, and the transducer 11 selected as the transmitting transducer and the receiving transducer is sequentially switched.

  The transmission / reception control unit 22 transmits an ultrasonic wave from the transmission transducer into the test piece by giving a driving electrical signal to the transmission transducer selected by the transducer scanning unit 21. The transmission / reception control unit 22 is also an electric signal corresponding to the reflected wave received by the receiving vibrator, that is, the reflected wave transmitted from the transmitting vibrator and reflected by the artificial defect formed in the test piece. Receive. The electrical signal corresponding to the reflected wave received by the transmission / reception control unit 22 is recorded in the data recording unit 23 in association with the flaw detection conditions including the combination of the transmission transducer and the reception transducer at this time.

The flaw detection condition determination unit 24 identifies the most preferable electric signal of the reflected wave by analyzing the electric signal accumulated in the data recording unit 23, and determines the flaw detection condition associated with the electric signal as the optimum flaw detection. Determine as a condition.
The analysis unit 25 analyzes the electrical signal corresponding to the reflected wave obtained in the flaw detection inspection for the actual machine, that is, the inspection object, thereby sizing defects such as cracks occurring in the inspection object, for example, the position Detection, size detection, etc. are performed.

Next, a flaw detection condition determination method for determining an optimum flaw detection condition at a specific position of the test piece using the ultrasonic flaw detection apparatus 10 having such a configuration will be described.
First, a test piece made of the same material as that of the inspection object is prepared, and a crack is artificially formed at a predetermined position of the test piece by the same procedure as that for a crack that actually occurs in the inspection object. For example, a chemical crack is impregnated at a predetermined position of the test piece to generate a pseudo crack similar to a crack that actually occurs.
Subsequently, the probe 12 is set on the test piece, and the ultrasonic flaw detector 10 is activated in this state.
FIG. 2 is a cross-sectional view of the test piece when the probe 12 is set on the test piece. In FIG. 2, reference numeral S denotes a joining portion such as stainless steel that joins the member S1 and the member S2. Reference numeral G is a crack artificially formed in the joint S.

In this state, first, the transducer scanning unit 21 of the control unit 20 selects a transducer region to be driven as a transmission transducer. Here, as shown in FIG. 3, a region A of 3 rows and 4 columns at the right end is selected.
Subsequently, the transducer scanning unit 22 selects a transducer region to be driven as a receiving transducer. Here, the leftmost 3 × 4 region a shown in FIG. 3 is selected.

Next, the transducer scanning unit 21 selects a transducer for transmission from the transducers belonging to the region A. Here, as shown in FIG. 4, the transducer group A1 including the three transducers 11 arranged in the first row is selected as the transmission transducer as the transmission transducer.
Subsequently, the transducer scanning unit 21 selects a receiving transducer from the transducers belonging to the region a. Here, as shown in FIG. 4, the transducer group a1 including the three transducers 11 in the first row is selected as the reception transducer as the reception transducer.

  In this way, when the transmission transducer and the reception transducer are selected, these pieces of information are given to the transmission / reception control unit 22. The transmission / reception control unit 22 transmits an ultrasonic wave from each ultrasonic wave 11 by giving a drive electric signal to each vibrator 11 constituting the vibrator group A1 selected as the transmission vibrator. As a result, as shown in FIG. 5, an ultrasonic beam that is a composite wave of ultrasonic waves transmitted from each transducer 11 is reflected at a predetermined position in the joint S of the test piece, and this reflected wave is received. Received by each vibrator 11 constituting the vibration group a1 selected as the vibrator.

  In this case, the transmission / reception control unit 22 focuses the ultrasonic beam transmitted by the transducer group A1 by changing the incident angle of the ultrasonic wave transmitted by each transducer 11 of the transducer group A1 at a predetermined angular interval. The position is moved little by little vertically and horizontally within the joint S of the test piece. As a result, the reflected waves reflected at slightly shifted positions can be received by the receiving transducer a1.

  Thus, the electrical signal corresponding to the reflected wave received by the receiving transducer a1 is a combination of the transmitting transducer A1 and the receiving transducer a1 when this electrical signal is received, and the ultrasonic wave. The data is recorded in the data recording unit 23 in association with the flaw detection conditions including various information such as the incident angle of the beam and the refraction angle of the reflected wave.

  When the ultrasonic flaw detection by the transducer group A1 and the transducer group a1 is completed, the transducer scanning unit 21 uses the next transducer group, for example, as shown in FIG. Then, the transducer groups A2 and a2 in the second row adjacent to the transducer groups A1 and a1 that have been selected so far are selected. Thereby, ultrasonic flaw detection by the transducer group A2 and the transducer group a2 is performed in the same procedure, and the electric signal of the reflected wave at that time is recorded in the data recording unit 23 in association with the flaw detection conditions.

  In this way, when the transducers for transmission and the transducers for reception are sequentially switched, and all the transducers in the region A and the region a are selected, the transducer scanning unit 21 performs the region A and the region a. Choose different areas. Here, as shown in FIG. 7, instead of the region A, a region B of 3 rows and 4 columns adjacent to the region A is selected, and a region of 3 rows and 4 columns adjacent to the region a instead of the region a. Select b.

  For these regions B and b, the transmitting transducer and the receiving transducer are sequentially switched in the same procedure as the above-described regions A and a, and the flaw detection results at that time are associated with the flaw detection conditions and data Recorded in the recording unit 23.

In this way, when the electric signals of the reflected waves under a plurality of different flaw detection conditions are acquired and recorded in the data recording unit 23, the flaw detection condition determination unit 24 determines the optimum flaw detection conditions based on these electric signals. decide. Specifically, the flaw detection condition determination unit 24 extracts the electric signal having the highest SN ratio from the electric signals recorded in the data recording unit 23, and optimizes the flaw detection conditions when the electric signal is obtained. Determined as flaw detection conditions.
This optimum flaw detection condition is used in ultrasonic flaw inspection on an actual inspection object, as shown below.

In the case of inspecting the inspection object by applying the flaw detection conditions determined by the flaw detection condition determining unit 24, the transmission / reception control unit 22 performs transmission under the optimal flaw detection conditions in a state where the probe 12 is set on the inspection object. The vibrator and the receiving vibrator are driven. For example, when the transducer group A2 is selected as the transducer for transmission and the transducer a2 for reception is selected as the optimum flaw detection condition, the transmission / reception control unit 22 provides a drive electrical signal to the transducer group A2. Note that the electrical signal for driving at this time is a signal for transmitting ultrasonic waves at an incident angle which is an optimum flaw detection condition.
As a result, an ultrasonic beam is transmitted from the transducer group A2 to the inspection object at an optimum incident angle. This ultrasonic beam is reflected according to the state of the defect at the focal position, and is received by the transducer group a2 when this reflected wave is under the optimum flaw detection condition.

  The electrical signal corresponding to the reflected wave is received by the transmission / reception control unit 22 and output to the analysis unit 23. The analysis unit 23 analyzes the electrical signal to identify the presence / absence of a defect at the focused position of the ultrasonic beam, and the size, shape, etc., if a defect has occurred. In this way, the ultrasonic inspection is performed on the actual inspection object under the inspection conditions determined as the optimal inspection conditions for the test piece made of the same material as the inspection object, thus improving inspection accuracy. It becomes possible to make it.

  In the actual machine inspection, as shown in FIG. 8, the incident angle of the ultrasonic wave transmitted from the transducer group A2 by the transmission / reception control unit 22 and the refraction angle in the transducer group a2 are changed at predetermined angular intervals. It is also possible to make it. Thus, in the actual machine inspection, the flaw detection conditions can be finely adjusted by changing the incident angle and the refraction angle at predetermined angular intervals.

  Then, it is possible to further improve the inspection accuracy by comparing the electric signals of the reflected waves when the flaw detection conditions are adjusted in this way and analyzing the defect using the electric signal having the highest SN ratio. . In this way, in the actual machine, ultrasonic flaw detection is performed while adjusting the flaw detection conditions determined as the optimum flaw detection conditions, and the results are compared to analyze the defects, so individual differences between the actual machine and the test piece It is possible to eliminate the inspection error due to the defect and to analyze the defect with high accuracy.

  As described above, according to the ultrasonic flaw detection apparatus according to the present embodiment, when determining the optimum flaw detection conditions, the transmitting vibrator and the receiving vibrator are automatically and sequentially switched. Ultrasonic waves can be automatically transmitted from a plurality of different positions, and reflected waves can be received at a plurality of different positions. This makes it possible to easily record data of reflected waves under various flaw detection conditions without bothering the inspector. And based on this result, optimal flaw detection conditions can be extracted.

  Further, by changing the incident angle and the refraction angle at each transmission / reception position, it becomes possible to determine a finer flaw detection condition. Thereby, the inspection accuracy can be further improved.

  In addition, even when performing the flaw detection inspection of the inspection object by applying the above-mentioned optimal flaw detection conditions, the flaw detection conditions are adjusted by changing the incident angle and the refraction angle of the ultrasonic wave at predetermined angular intervals, so that the test is performed. The error between the piece and the actual machine can be eliminated, and the flaw detection result under the optimum flaw detection conditions for the actual machine can be obtained. Thereby, a defect can be analyzed with high accuracy.

  In this embodiment, after the areas A and a are selected, the areas B and b that do not overlap with the areas A and a are selected. Instead, as shown in FIG. The regions C and c obtained by shifting the regions A and a by one column may be selected. In this way, by shifting the region by one row, it is possible to obtain a flaw detection result under more detailed flaw detection conditions.

Moreover, in this embodiment, although the area | region was selected as mentioned above, selection of this area | region can be abbreviate | omitted. For example, a transmitting transducer and a receiving transducer may be arbitrarily selected from a plurality of transducers arranged two-dimensionally without defining these areas. It is also possible to select a vibrator once selected a plurality of times.
Furthermore, since each transducer can be applied to both a transducer for transmission and a transducer for reception, the transducer selected as the transducer for transmission can be used again as a transducer for reception thereafter. Good.

  The order of selecting the transmitting transducer and the receiving transducer is not limited to the above example. For example, the selection sequence may be registered in advance and the transducer may be selected based on this sequence. At this time, as in the above-described embodiment, in addition to the scanning method of sequentially selecting adjacent transducers, a selection method of sequentially selecting transducers at random may be used.

  In this embodiment, three transducers each having one row and three columns are handled as one set, and ultrasonic waves are transmitted from the three transducers. However, the ultrasonic transducers are driven simultaneously, that is, the ultrasonic waves are transmitted substantially simultaneously. There is no limitation on the number of vibrators to be operated. For example, it may be driven one by one, or two-dimensionally arranged transducers of n × m may be driven simultaneously.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

It is the figure which showed schematic structure of the ultrasonic flaw detector which concerns on one Embodiment of this invention. It is sectional drawing when a probe is installed in the test piece. It is a figure for demonstrating the setting of an area | region. It is a figure for demonstrating selection of the vibrator | oscillator for transmission, and the vibrator | oscillator for reception. It is a figure for demonstrating a state when an ultrasonic wave is transmitted from the vibrator | oscillator for transmission, and the reflected wave is received by the vibrator | oscillator for reception. It is a figure for demonstrating selection of the vibrator | oscillator for transmission, and the vibrator | oscillator for reception. It is a figure for demonstrating the setting of an area | region, and selection of the vibrator | oscillator for transmission, and the vibrator | oscillator for reception. It is a figure for demonstrating the case where an incident angle and a refraction angle are changed in the flaw detection inspection of a test object. It is the figure which showed the other selection example of the area | region.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ultrasonic flaw detector 11 Transducer 12 Probe 20 Control part 21 Transducer scanning part 22 Transmission / reception control part 23 Data recording part 24 Flaw detection condition determination part 25 Analysis part

Claims (4)

A probe comprising a plurality of transducers arranged two-dimensionally;
At least one of the plurality of transducers is selected as a transmission transducer, and at least one reception transducer paired with each of the transmission transducers is selected, and the transmission transducer And a transducer scanning section for sequentially switching transducers to be selected as the receiving transducer,
Transmission / reception control for transmitting ultrasonic waves from the transmitting vibrator toward the artificial defect formed at a specific position in the test piece and receiving the reflected wave reflected by the artificial defect by the receiving vibrator And
An ultrasonic wave comprising: a data recording unit for storing an electrical signal of a reflected wave received by the receiving transducer in association with a flaw detection condition including information on a combination of the transmitting transducer and the receiving transducer at that time Flaw detection equipment.   The transmission / reception control unit changes at least one of an incident angle of an ultrasonic wave transmitted from the transmitting transducer and a refraction angle of a reflected wave received by the receiving transducer at a predetermined angular interval. The described ultrasonic flaw detector.   The ultrasonic flaw detection apparatus according to claim 1, further comprising a flaw detection condition determining unit that determines an optimum flaw detection condition by analyzing data accumulated in the data recording unit. In the case of performing ultrasonic flaw detection of an inspection object under the flaw detection conditions determined by the flaw detection condition determination unit,
The transmission / reception control unit changes at least one of an incident angle of the transmission vibrator and a refraction angle of the reception vibrator at a predetermined angular interval, and determines a defect based on the reflected wave received at this time. The ultrasonic flaw detector according to claim 3 which performs analysis.

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