JPH09257763A - Array ultrasonic flaw detection method and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the dimension of a reflecting object (flaw) by calculating the max. scanning quantity wherein the peak of the receiving sensitivity distribution between the elements of an array probe is received within the range of the definite distance from the center of a transmission element group. SOLUTION: An array probe 1 is set to a flaw detection place and elements are electronically driven in the arranging direction of them while timing is controlled by an array controller 3. The scanning distance of the probe 1 at this time is calculated by a scanning quantity calculator 4. The ultrasonic waves transmitted from the elements are reflected by a reflecting object and the reflected waves therefrom are received by the respective elements. The receiving sensitivities of the respective elements and the distribution state thereof are calculated by a sensitivity distribution calculator 5. A peak detector 6 calculates the peak of this distribution state. A flaw length calculator 7 calculates the max. scanning quantity wherein the peak of the receiving sensitivity distribution is received within the range of the definite distance from the center of a transmission element group from the scanning quantity and peak calculated by the scanning quantity calculator 4 and the peak detector 6 to calculate the length of the reflecting object (flaw) from the calculated value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting flaws in, for example, a welded portion by using an array probe having a plurality of arrayed fine elements.

[0002]

2. Description of the Related Art The following method is known as a conventional array ultrasonic flaw detection method. a. By using the array probe 1 having a plurality of fine elements 2 arranged as shown in FIGS. 8A and 8B, the driving timing is changed or the set of elements 2 to be driven is switched, Further, it is a technique that enables electronic scanning, deflection and focusing of ultrasonic waves by a combination thereof, where (a ') shows electron deflection and (b') shows electron focusing.

B. The signals transmitted from the elements 2 of the array probe 1 shown in FIGS. 8A and 8B, which are reflected from the reflectors (scratches), are individually received by the elements 2. A technique for estimating the shape of a reflector (scratch) from the reception sensitivity distribution between the elements 2 ... And the reception time distribution (for example, Japanese Patent Application No. 7-140928).

C. 9A and 9B show a conventional probe 1a.
Fig. 2 shows a method for measuring a flaw length by mechanically scanning (moving) the, for example, in the case of a flaw existing in the welded portion A in (a), the echo height of the flaw found in advance is After finding the maximum position P and scanning the probe 1a from that position in the welding line direction, as shown in (b), the length of the range exceeding a certain sensitivity, or a half or more of the maximum echo height is detected. This is a method (JISZ 3060-1996, Architectural Institute of Japan Standard-1989) in which the length l in the range of the echo height h is used as the flaw length.

[0005]

However, the above conventional example has the following disadvantages. a. In the case of a, since the advantage of being an array is utilized only for transmission, the sensitivity of the reception echo is mainly used in flaw sizing and the like as in the conventional ultrasonic flaw detection method. However, there is not much theoretical explanation for the threshold value of the sensitivity, and there are aspects that are empirically determined, and the reliability is low.

B. In the case of b, the merit of being an array is used for reception as well, but the flaw size and element size and A /
The accuracy improvement range is limited due to the performance of the D converter.

C. In the case of c, it is known that the two methods show relatively correct values, but the theoretical basis is not sufficient.

[0008]

The present invention provides a method and apparatus for accurately determining the size of a reflector (length in the element array direction) in a flaw detection method using an array probe. The purpose is to have the following structure.

1. By scanning the array probe in the array direction of the elements, the receiving sensitivity distribution between the elements and the peak of this distribution are detected, and the maximum scanning amount at which the peak is within a certain distance from the center of the transmitting element group is obtained. Array ultrasonic testing method to evaluate the size of the reflector from the value.

[0010] 2. An array controller that electronically scans the array probe in the array direction of the elements by changing the combination of the driven element groups while driving the array probe, and the array controller that scans the array probe A scanning amount calculator for obtaining the distance, a reception sensitivity distribution calculator for obtaining the reception sensitivity distribution of the ultrasonic waves received by the array probe for each channel, and a reception sensitivity distribution calculated by the reception sensitivity distribution calculator Of the peak detector for obtaining the peak of, the scanning amount obtained by the scanning amount calculator and the peak of the reception sensitivity distribution obtained by the peak detector are obtained at the maximum scanning amount within a fixed distance from the center of the transmitting element group, An array ultrasonic flaw detector comprising a flaw length calculator for obtaining the size of a reflector from a value.

3. An array controller that drives the array probe, a scanning device that mechanically scans the array probe in an element array direction, and a scanning amount calculator that determines a distance over which the scanning device scans the array probe. A reception sensitivity distribution calculator that obtains the reception sensitivity distribution of the ultrasonic waves received by the array probe for each channel, and a peak detector that obtains the peak of the reception sensitivity distribution calculated by the reception sensitivity distribution calculator , The maximum scanning amount in which the scanning amount obtained by the scanning amount calculator and the peak of the receiving sensitivity distribution obtained by the peak detector are within a certain distance from the center of the transmitting element group, and the dimension of the reflector is obtained from this value. An array ultrasonic flaw detector consisting of a flaw length calculator.

4. An array controller that electronically scans the array probe in the element array direction by changing the combination of the driven element groups while driving the array probe, and the array probe in the element array direction. A scanning device that mechanically scans, a scanning amount calculator that obtains the array controller and the scanning distance of the array probe by the scanning device, and a channel for receiving the sensitivity distribution of the ultrasonic waves received by the array probe. Reception sensitivity distribution calculator to be obtained for each, a peak detector to obtain the peak of the reception sensitivity distribution calculated by the reception sensitivity distribution calculator, the scanning amount obtained by the scanning amount calculator and the reception obtained by the peak detector An array ultrasonic probe that consists of a flaw length calculator that finds the maximum scanning amount at which the peak of the sensitivity distribution falls within a certain distance from the center of the transmitting element group and finds the size of the reflector from this value. Apparatus.

[0013]

When performing flaw detection, the array probe is set at the flaw detection position, and the elements are electronically driven in the array direction while controlling the timing by the array controller. Or
The array probe itself is mechanically moved by 1 mm by the scanning device, and the elements are driven by the array controller. Alternatively, the drive timing of the element is electronically controlled, and at the same time, the array probe is mechanically moved. The scanning distance of the element or (and) array probe at this time is calculated by the scanning amount calculator. The ultrasonic waves transmitted from the elements are reflected by the reflector, and the reflected waves are received by the respective elements.
Then, the reception sensitivity distribution calculator calculates the reception sensitivities of the respective elements and the distribution state of the received reflected waves.
The peak detector finds the peak of the distribution state. The flaw length calculator, from the scanning amount and peak obtained by the scanning amount calculator and the peak detector, obtains the maximum scanning amount at which the peak of the receiving sensitivity distribution is within a certain distance from the center of the transmitting element group,
The length of the reflector (scratch) is obtained from this value.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of an array probe used in the present invention is shown in FIGS. 1 (a) (b) and 2 (a) (b).
Shown in 1 is an array probe in which elements 2 are arranged in a horizontal direction, and in FIG. 2, 1 is an array probe in which elements 2 are arranged in a vertical direction. In (a), the arrow indicates the ultrasonic wave transmission direction. The array probe 1 shown in FIGS. 1 and 2 scans by electrically or mechanically driving the elements 2 ... In the array direction of the elements 2 ,. It is possible to move).

[Embodiment 1] FIG. 3 is an electronic scanning type array ultrasonic flaw detector, showing an embodiment of the invention of claims 1 and 2, wherein reference numeral 1 is an array probe and 3 is an array controller. The array probe 1, the elements 2, ... Are electronically driven at the same time or for each group or with a time lag.

Reference numeral 4 denotes a scanning amount calculator, which calculates the distance scanned by the array probe 1 (element 2). A receiver sensitivity distribution calculator 5 calculates the receiver sensitivity distribution of each element 2 ... When the elements 2 ... In the array probe 1 are simultaneously driven. A peak detector 6 detects a peak of the reception sensitivity distribution calculated by the reception sensitivity distribution calculator 5.

Reference numeral 7 denotes a flaw length calculator, which has a maximum distance within a certain distance from the center of the transmitting element group from the scanning amount calculated by the scanning amount calculator 4 and the peak detected by the peak detector 6. Find the scanning amount. Find the length of the flaw from this value.

[Embodiment 2] FIG. 4 shows a mechanical scanning type array ultrasonic flaw detector, which is an embodiment of the invention of claims 1 and 3, wherein the scanning device 8 mechanically operates the array probe 1. Is scanned, and the amount scanned by the scanning device 8 is calculated by the scanning amount calculator 4. The flaw length is calculated in the same manner as in the first embodiment.

[Embodiment 3] FIG. 5 shows an array ultrasonic flaw detector using both the electronic scanning method (Embodiment 1) and the mechanical scanning method (Embodiment 2). Element 2
.. are electronically driven by the array controller 3, and at the same time the array probe 1 is moved by the scanning device 8, and the scanning amounts of both of them are calculated by the scanning amount calculator 4. The flaw length is calculated in the same manner as in the first embodiment.

FIGS. 6A and 6B are explanatory views showing changes in the transmitted sound field when the array probe 1 is scanned along the reflector x. From this figure, it can be seen that the sound field gradually moves from the center of the elements 2.

7A and 7B show the array probe shown in FIG. 1 (hereinafter referred to as "A type") and the array probe shown in FIG. 2 (hereinafter referred to as "B type"). This is the data when the change in the reception sensitivity distribution is investigated. In this way, data is taken while scanning the array probe 1, and the length of the flaw is obtained from this data. For example, in flaw detection of a through vertical slit by the A type array probe 1, the center of the 6 mm slit is aligned with the center of the array probe 1, and the array probe 1 is moved laterally by 1 mm from there. (A),
In the flaw detection of the slit by the B type array probe 1,
The array probe 1 was arranged at a position where the echo by the slit of 2 mm was maximized at the fifth element, and the array probe 1 was moved back and forth by 1 mm (b). In the case of the A type, it can be seen that the range position where the sensitivity distribution shows a substantially constant value is gradually moving. When the amount of movement is 4 mm, this range deviates from the corresponding element (No. 5 or No. 6). This shows that the slit width is 6 mm. Further, in the case of the B type, when the movement amount becomes 3 mm, the maximum of the sensitivity distribution deviates from the element No. 5 or 6 corresponding to the center. When this is converted into a slit by the formula 1, the height becomes 1.7 mm.

[0022]

(Equation 1) However, h: slit height (mm), d: probe movement amount (mm), θ ₁ steel refraction angle, θ ₂ : acrylic refraction angle.

[0023]

As described above, according to the present invention, the array probe is scanned, and the amount of this scanning amount and the peak of the receiving sensitivity distribution are within a certain distance from the center of the transmitting element group.
Was evaluated as the dimension (length). As a result,
Since the distribution shape is determined by the relative relationship between the transmitted sound field and the reflector, it is possible to theoretically explain the change, and it is reliable with respect to the method of measuring the reflector length of c described in the prior art. Can be improved. In addition, in the method of estimating the shape of the reflector described in b) in the prior art, mechanical scanning or electronic scanning should be used to reduce the influence of the limit of the device capability such as the element size on the resolution and sizing. Is possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an array probe in which elements are arranged in a lateral direction.

FIG. 2 is an explanatory diagram of an array probe in which elements are arranged in a vertical direction.

FIG. 3 is an explanatory diagram of an electronic scanning flaw detector.

FIG. 4 is an explanatory view of a mechanical scanning type flaw detection device.

FIG. 5 is an explanatory diagram of a flaw detection device that combines an electronic scanning method and a mechanical scanning method.

FIG. 6 is an explanatory diagram of movement of a transmission sound field.

FIG. 7 is an explanatory diagram of a relationship between a flaw detection slit width and a reception sensitivity distribution in a flaw detection test.

FIG. 8 is an explanatory diagram of a conventional flaw detection method performed by changing a drive timing or a set in a conventional technique.

FIG. 9 is a view for explaining a peak of a reflected wave displayed on an oscilloscope in the related art, a change in the peak of the reflected wave when a flaw length and an array probe are scanned, and a change distribution of this flaw. Explanatory drawing of the method of calculating | requiring length.

[Explanation of symbols]

 1 array probe 2 ... element 3 array controller 4 scanning amount calculator 5 reception sensitivity distribution calculator 6 peak detector 7 flaw length calculator 8 scanning device

Claims (4)

[Claims] 1. A maximum scanning in which a receiving sensitivity distribution between elements and a peak of this distribution are detected by scanning an array probe in an element array direction, and the peak is within a certain distance from the center of a transmitting element group. An array ultrasonic flaw detection method that obtains the quantity and evaluates the dimensions of the reflector from this value. 2. A controller for driving the array probe and electronically scanning the array probe in the element arrangement direction by changing the combination of driven element groups, and the array controller A scanning amount calculator for obtaining the distance at which the probe is scanned, a reception sensitivity distribution calculator for obtaining the reception sensitivity distribution of the ultrasonic waves received by the array probe for each channel, and the reception sensitivity distribution calculator for calculating And a peak detector for obtaining the peak of the receiving sensitivity distribution, and the maximum scanning amount for which the scanning amount obtained by the scanning amount calculator and the peak of the receiving sensitivity distribution obtained by the peak detector are within a certain distance from the center of the transmitting element group. An array ultrasonic flaw detector consisting of a flaw length calculator and a reflector length calculator. 3. An array controller that drives the array probe, a scanning device that mechanically scans the array probe in the direction in which the elements are arranged, and a distance that the scanning device scans the array probe. A scanning amount calculator to be obtained, a reception sensitivity distribution calculator for obtaining the reception sensitivity distribution of the ultrasonic waves received by the array probe for each channel, and a peak of the reception sensitivity distribution calculated by the reception sensitivity distribution calculator The peak detector to be obtained and the scanning amount obtained by the scanning amount calculator and the maximum scanning amount at which the peak of the reception sensitivity distribution obtained by the peak detector falls within a certain distance from the center of the transmitting element group, are reflected from this value. An array ultrasonic flaw detector consisting of a flaw length calculator that determines the body size. 4. An array controller for driving an array probe and electronically scanning the array probe in an element array direction by changing a combination of driven element groups, and the array probe. A scanning device that mechanically scans in the array direction of the elements, a scanning amount calculator that obtains a distance over which the array controller and the scanning device scan the array probe, and an ultrasonic wave received by the array probe. A receiving sensitivity distribution calculator that obtains a receiving sensitivity distribution for each channel, a peak detector that obtains a peak of the receiving sensitivity distribution calculated by the receiving sensitivity distribution calculator, and a scanning amount and peak detection that are obtained by the scanning amount calculator The peak length of the receiver sensitivity distribution obtained by the detector is found at the maximum scanning distance within a certain distance from the center of the transmitter element group, and the size of the reflector is obtained from this value. Array ultrasonic flaw detector.