JP2948061B2 - Ultrasonic testing method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flaw detection method and apparatus applied to welding defect inspection and the like, and more particularly to a method for detecting a position of a reflection source based on ultrasonic echoes when performing automatic flaw detection. Further, the present invention relates to an ultrasonic flaw detection evaluation method and apparatus capable of improving the evaluation accuracy of defects and the like.

[0001]

2. Description of the Related Art In a defect inspection of a steel welded portion or the like based on an ultrasonic flaw detection method, an ultrasonic probe is scanned along a surface of a material such as a steel material, and an ultrasonic wave emitted from the ultrasonic probe is scanned. The defect position is specified by detecting the echo height of the beam.

That is, since the reflected echo of an ultrasonic beam becomes large at a welding defect or the like in a material, a position where the echo height is large is specified by detecting based on positional information of the ultrasonic probe. Things.

FIG. 8 schematically shows the principle of the ultrasonic flaw detection. As shown in FIG. 1A, when an ultrasonic beam 2 emitted from an ultrasonic probe 1 propagates through a material 3 to be inspected, the beam center O increases as the distance from the ultrasonic probe 1 increases. , The sound wave energy gradually weakens, and spreads in a three-dimensional bundle as indicated by an arrow a at a constant three-dimensional directivity angle. That is, the sound field of the ultrasonic beam is not uniform.

As shown in FIG. 1A, when a defect 4 is present in the material 3 to be inspected, the vertical axis indicates the echo height and the horizontal axis indicates the moving distance of the ultrasonic probe 1. In the graph 5, an echo curve B having a spread A 'similar to the spread A of the beam 2 is obtained, and a defect position in the inspection target material 3 is obtained based on the echo curve B and its position information and the like.

However, in this case, the defect is that the sound field of the ultrasonic beam is not uniform as described above, and the spread A 'of the echo curve B like the monitor image indicated by 4' in FIG. Based on this, it is expressed as a thick line that is long vertically and wide in the inspected material 3.

[0006]

When a welding defect inspection or the like is actually performed by the above-described method, a problem may arise in evaluating whether or not the reflection source is a true defect due to the spread of the ultrasonic beam. is there. That is, FIG. 9A schematically shows a state in which a flaw detector is used as the ultrasonic probe 1 and flaw detection of a welded portion is performed.

While the ultrasonic probe 1 is moving in the fixed scanning range C, the butt welding portion 6 of the steel plate as the material 3 to be inspected is
If there is a defect 4 (reflection source) inside, a reflected echo 7 from the defect 4 is obtained as shown in FIG. , 1
0 is obtained.

When the reflection sources are close to each other due to the above-mentioned spread of the ultrasonic beam, the reflection echoes 9 and 10 have a plurality of peak points P1 as shown in FIG.
, P2, and P3.

Thus, a plurality of peak points P1, P2,
When data of the continuous wave D having P3 is obtained, it is determined that P1 is a reflection echo of a defect, but P1 and P2 are echoes from a reflection source which is not a defect (hereinafter, referred to as shape echo). Then you can't do without much experience. On the other hand, in the case of displaying the cross section of the inspection unit in the automatic flaw detection, as shown in FIG. 9C, images E and F in which the reflection source is wider than the actual one corresponding to each envelope appear. in this case,
Although F is a shape echo, it penetrates to the weld and it is unclear whether it is a defect or not.

[0010] Conventionally, in the ultrasonic flaw detection technique which has been advanced from the point of labor saving, etc., an envelope having one peak point P1 and two peak points P2, P shown in FIG.
When an envelope having a 3 appears, each peak point P1, P2
, P3 without any particular consideration, it is assumed that there is a reflection source based on the envelope widths A1, A2. That is, as shown in FIG. 9C, assuming that the images of the reflection sources E and F are recognized within a certain range of the welded portion 6, a certain area t is removed from the actual plate thickness T to be narrow. A range is determined as an inspection range, and processing is performed to determine that the shape echoes 9 and 10 are not defect echoes. However,
In this case, in order to avoid erroneous detection, a method of excluding a region outside (the lower side of the figure) from the imaginary line G in the figure has to be taken, and the test range is narrowed accordingly.

It is possible to faithfully image the height of the reflected echo by color-coding the graph image for each reflection source, that is, by so-called colorization, and to determine the color-coded state by human eyes. However, in order to automate this, complicated image processing techniques are required, which is not suitable for practical use of flaw detection tests from the viewpoint of complicated equipment and operation or cost, and when performing high-speed processing. Is also an obstacle.

The present invention has been made in view of such circumstances, and it is possible to clearly discriminate between a defect echo and a shape echo, whereby the reflection source is defective or non-defect without requiring skill. It is an object of the present invention to provide an ultrasonic flaw detection evaluation method and apparatus capable of easily and surely judging whether a flaw is detected and expanding a flaw detection range over the entire thickness of a material to be inspected.

[0013]

As described above, the sound wave energy of the ultrasonic beam is gradually attenuated from the beam center toward the periphery, and the sound wave energy at the beam center is the highest. Therefore, it can be said that the reflection echo when the beam center with the highest energy hits the reflection source is the highest. When the probe is moved and the ultrasonic beam reaches the reflection source, first, a reflected echo occurs at the front end side in the traveling direction in the beam width, and when viewed from an oscilloscope,
The rising of the pulse wave is seen, and the height of the pulse wave (echo height) gradually increases with the subsequent movement of the probe, peaks at the passing point at the center of the beam, and then travels in the beam width. The echo height gradually decreases toward the end, and becomes zero after passing through the beam. The trajectory of the transition of the echo height is the echo curve "B" in the graph "5" in FIG. 8A, and the maximum value of the echo height in this echo curve is the peak point "P". .

Considering this peak point “P”,
For example, when the reflection source is spherical, the amount of reflection at the reflecting surface passing through the center of the sphere becomes the maximum, so that the peak point “P” obtained by the reflection of the center of the ultrasonic beam having the highest energy is obtained.
Will be at the center of the reflection source. That is, when this peak point “P” is projected on the image “4 ′” in FIG.
The reflection source will appear as a point at the center of this image "4 '". Even in the case of a shape other than a spherical shape, the peak point “P” appears on the surface having the largest reflection amount (not limited to the center position of the reflection source) among the reflection sources. By performing signal processing in such a manner as to project on the “4 ′”, the reflection source corresponding to the peak point “P” can be regarded as a point.

Therefore, for example, when the peak point “P ₂ ” in FIG. 9B is made to correspond to the image “F” (in the case of the shape echo) in FIG. It is considered that the intersection of the bottom surface of the material 3 and the bottom portion of the welded portion 6 becomes the largest reflection surface, and the peak point “P ₂ ” of the echo height appears at this point. The reflection source in the image “F” that projects this peak point “P ₂ ” is “point”.
The position of the “point” deviates from the area “A” illustrated in FIG. That is, it is "not a welding defect".

Thus, as a basic idea, the ultrasonic probe is scanned along the surface of the material to be inspected to detect an echo from a reflection source, a position of the ultrasonic probe, and an ultrasonic probe. The detection of the beam path from the probe to the reflection source proceeds synchronously with a constant pulse width. If the peak point of the detected echo height is within a certain area in the material to be inspected, the reflection source is regarded as a defect. It is conceivable that the evaluation is performed, and when the peak point is out of the region, it is evaluated as a non-defect.

According to this idea, based on the moving distance of the ultrasonic probe or the beam path between the ultrasonic probe and the reflection source of the ultrasonic wave, the position of the reflection source at which the peak point of the reflected echo appears is determined. If the specified reflection source is located within a certain area of the inspection object, the reflection source is evaluated as a defect, and if the specified reflection source is outside the same area, it is evaluated as a non-defect.

In this way, focusing on the peak point of the echo height, the reflection source is regarded as a "point", and if it is in a certain area, it is evaluated as a defect, and if it is outside the area, it is evaluated as a non-defect. Then, by considering the reflection source as a point, the region to which the reflection source belongs or not can be set widely over the entire thickness of the inspection object,
The entire range in the direction of the thick plate including the part that has been unclear due to the assumption as a conventional echo group can be an inspection target, and a practically favorable result can be obtained.

Therefore, if the position of the reflection source corresponding to the peak point is directly determined, and the defect / non-defect is evaluated based on the position, the part of the echo waveform including the peak point of the reflected echo is reflected by the reflection source. As compared with the method of roughly evaluating as, the range to be erased as a non-defect can be further reduced.

The inventor of the present invention has examined the relationship between the position where the peak point of the reflection echo appears and the beam path, and as a result, it has been found that the following tendency exists.

That is, FIG. 7 shows the relationship between the echo height H and the beam path W on the vertical axis and the probe position Y on the horizontal axis. As the ultrasonic probe is scanned along the incident direction of the ultrasonic beam, the beam path W gradually increases linearly as the ultrasonic probe moves away from the reflection source. Further, the echo height H draws a gentle envelope having peak values Hm and Hn each time there is a reflection source. In such a case, the beam path W does not gradually increase in a series, but changes greatly in a step state at the stage of transition from one envelope to another envelope (W1).

From this, the inventor has found that by observing the change in the beam path W together with the echo height H, it is possible to determine the difference between the reflection sources. That is, a constant reference value Δ in which the variation of the beam path W is determined based on the thickness of the object to be inspected, the type of the ultrasonic probe, and other factors.
If it is larger than W, it can be estimated that the reflection sources are independent. Conversely, if the variation of the beam path W is smaller than the reference value ΔW, it can be estimated that the reflection sources are a series.

The same applies to the change amount of the position Y of the ultrasonic probe. When the change amount of the position Y of the ultrasonic probe at the time of detecting the reflected echo is larger than the reference value ΔY, the reflection If the sources are independent and small, it can be estimated as a series.

Further, the inventor has found that it is possible to determine whether the reflection source is an independent one or an integrated one, by evaluating the continuity of the echo height H of the reflected echo.

That is, this is a method of grouping reflected echoes based on peak points. For example, when one independent reflection source exists alone without any other adjacent one, an envelope having one peak value Hm and having a small echo height at both tails appears as an echo curve. When the reflection sources are adjacent to each other, an echo shape having a plurality of peak values Hn and Hl appears in one envelope. In such a case, as described above, it is difficult to determine the independence of the reflection source in the related art.

However, the inventor has proposed that a plurality of peak values Hm, Hn, H
When 1 is included, each of the peak values Hm, Hn, and Hl and the change amounts H1, H2, H3, and H4 of the echo height up to the local minimum value before and after the peak value are compared with a fixed reference value ΔH. Then, the change amounts H1, H2, H3,
It has been found that when H4 is larger than the reference value ΔH, the reflection sources are independent, and when H4 is smaller, the reflection sources are a series of reflection sources. This reference value can be set based on conditions such as the welding material and form, and the type of ultrasonic probe.

According to the first aspect of the present invention, the ultrasonic probe is scanned along the surface of the material to be inspected, and the echo detection from the reflection source and the beam path detection from the ultrasonic probe to the reflection source are fixed. Advancing synchronously with the pulse width, the amount of change in the beam path and the amount of change in the echo height from the previous echo detection position are obtained for each echo detection position, and based on each change amount, (1) The change amount of the beam path from the echo detection position to the current echo detection position is compared with a fixed reference value, and if the change amount of the beam path is smaller than the reference value, a series of successive echo groups is determined to be the same group, If it is large, it is determined to be another group. (2) When the same group is made by the operation (1) based on the beam path change amount, a plurality of peak values are included in a continuous echo group. When compared each peak value and the echo height constant reference value the amount of change in the minimum value before and after,
When the echo height change amount is smaller than the reference value, a series of successive echo groups is determined to be the same group, and when the echo height change amount is larger, the group is determined to be another group. As a result, it is evaluated that there is an independent reflection source for each echo group of each group, and the position of each reflection source is specified based on the position information of the ultrasonic probe and the beam path information. It is characterized in that it is evaluated as the position in the material to be inspected corresponding to the peak point of the echo height to be measured.

According to the present invention, when the change amount of the beam is larger than the reference value by the operation (1), the echo group can be determined to be another group with the position corresponding to that portion as a boundary. It can be seen that there is an independent reflection source for each group.

Further, even when the group is determined to be the same group by the operation (1), the determination of each of the envelopes of the echo heights is performed supplementarily by the operation (2), so that a plurality of peak points can be determined. In some cases, it is found that the head is equal to or larger than a predetermined value. In this case, it is understood that the echo sources are grouped into a plurality of echo groups and different reflection sources are present corresponding to the respective peak points.

According to a second aspect of the present invention, an ultrasonic probe is scanned along the surface of a material to be inspected, and echo detection from a reflection source, position detection of the ultrasonic probe, and detection of an echo from the ultrasonic probe are performed. Detection of the beam path to the reflection source proceeds synchronously with a constant pulse width, and for each echo detection position, the amount of change in the position of the ultrasonic probe from the previous echo detection position, the change in the beam path, and the echo height (1) comparing the position change amount of the ultrasonic probe from the previous echo detection position to the current echo detection position with a certain reference value, and calculating the position change If the amount is smaller than the reference value, a series of successive echo groups is determined to be the same group, and if larger, it is determined to be another group. (2) The above-mentioned (1) based on the amount of change in the position of the ultrasonic probe The same group by the operation of The change amount of the beam path from the previous echo detection position to the current echo detection position is compared with a certain reference value, and when the change amount of the beam path is smaller than the reference value, a series of successive echo groups are grouped together. (3) If the same group is obtained by the operations (1) and (2) based on the amount of change in the position of the ultrasonic probe and the amount of change in the beam path, (3) In, when a plurality of peak values are included in a continuous echo group, by comparing the amount of change in the echo height between each peak value and the minimum value before and after that peak value with a certain reference value,
When the echo height change amount is smaller than the reference value, a series of successive echo groups is determined to be the same group, and when larger, the group is determined to be another group, and the above-mentioned operations (1) to (3) are performed. As a result, it is evaluated that there is an independent reflection source for each echo group of each group, and the position of each reflection source is specified based on the position information of the ultrasonic probe and the beam path information. It is characterized in that it is evaluated as the position in the material to be inspected corresponding to the peak point of the echo height to be measured.

According to the present invention, prior to the determination based on the change in the beam path as in the first aspect of the present invention, the group is determined based on the position change of the ultrasonic probe. When the echo group is determined to be another group in the determination step based on the position change, the reflection source can be easily specified without performing determination based on the beam path and the echo height.

According to a third aspect of the present invention, in the ultrasonic flaw detection evaluation method according to the first or second aspect, if it is determined that the reflection source is within a certain area in the material to be inspected, the reflection source is set to a predetermined area. A defect is evaluated, and when it is determined that the reflection source is out of the area, it is evaluated as a non-defect.

In the present invention, for example, the test range is set over the entire cross-sectional shape of the material to be inspected, and the position of the peak point extracted by the method of the present invention is determined by an ultrasonic test. When the position of the peak point is not included in the set test range, the reflection source of the corresponding echo is evaluated as non-defective.

According to the present invention, the position of the reflection source in the material is clearly grasped as a point by the method of grouping the peak points of the reflection echo, and then the reflection source which becomes a shape echo and other unnecessary echoes is not defective. Therefore, for example, the test area can be expanded over the entire thickness of the material to be inspected.

Therefore, the distinction between the defect echo and the shape echo can be clearly performed, whereby it is possible to easily and reliably determine whether the reflection source is a defect or a non-defect without requiring skill, and to determine whether the reflection source is defective or not. An accurate depth position from the ultrasonic probe can be detected with high accuracy, and the flaw detection range can be extended over the entire thickness of the material to be inspected.

According to a fourth aspect of the present invention, there is provided an ultrasonic probe scanned along a surface of a material to be inspected, a position detector for detecting a position of the ultrasonic probe, and an echo from a reflection source. An echo detector for detecting a height, a beam path detector for detecting a beam path from the ultrasonic probe to a reflection source, and a position signal output from the position detector, and each echo detection position For each time, the position change amount of the ultrasonic probe from the previous echo detection position is obtained, and the position change amount is compared with a certain reference value. If the change amount is smaller than the reference value, both echoes belong to the same reflection source. A probe position change amount continuity evaluation means for the same group, and when the echoes are larger than a reference value, both echoes belong to non-identical groups belonging to different reflection sources, and a beam path signal output from the beam path detector is input. And each echo detection For each position, the amount of change in the beam path from the previous echo detection position is calculated, and the amount of change in the beam path is compared with a certain reference value. If smaller than the reference value, both echoes belong to the same reflection source belonging to the same group. Inputting the echo signal output from the echo detector, and inputting the echo signal output from the echo detector, when both echoes are not the same group belonging to different reflection sources, When multiple peak values are included in the echo group, the amount of change in echo height from each peak value to the subsequent minimum value is calculated, and each of the echo height changes is compared with a fixed reference value. Then, if it is smaller than the reference value, both echoes belong to the same group belonging to the same reflection source,
When the echo values are larger than the reference value, the echo height change amount continuity evaluation means as non-identical groups in which both echoes belong to different reflection sources, and continuity evaluation signals from each of these evaluation means, Each time, the position of the reflection source in the material to be inspected is determined based on the position information and the beam path information of the ultrasonic probe corresponding to the peak value of the echo height, and the reflection source is included in the material to be inspected. A defect evaluation means is provided which evaluates a defect when it is within a certain area and evaluates it as a non-defect when it is outside the area.

According to the present invention, the method of claims 1 to 3 can be automatically carried out, and can be effectively used as an automatic ultrasonic flaw detector for welding defect inspection and the like.

Moreover, since the apparatus of the present invention does not require a specially complicated image processing mechanism or the like, it can be implemented very easily.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a schematic configuration of an automatic ultrasonic flaw detection evaluation apparatus according to the present embodiment, and FIGS. 2 and 3 show a detailed circuit configuration of the same apparatus. 4 to 6 show the procedure of the automatic ultrasonic flaw detection evaluation method according to this embodiment, and FIG. 7 shows the operation.

FIG. 1 shows an automatic ultrasonic inspection and evaluation system according to this embodiment.
As shown in FIG. 1, an ultrasonic probe (probe) 12 automatically scanned along the surface of the inspection object material 11, a position detector 13 for detecting a position Y of the ultrasonic probe 12, A beam path detector 14 detects a beam path W from the acoustic probe 12 to the reflection source a, and an echo detector 15 detects an echo height H from the reflection source a.

Based on the detection signals from the detectors 13, 14, and 15, the amounts of change in the probe position Y, the beam path W, and the echo height H are determined, and a probe for evaluating the continuity / discontinuity thereof is obtained. Position change amount continuity evaluation means 16,
A beam path continuity evaluation unit 17 and an echo height variation continuity evaluation unit 18 are provided, and evaluation signals from these evaluation units 16, 17, and 18 are input to the reflection source a.
Is provided with defect evaluation means 19 for evaluating whether or not is a defect and display means 20 for displaying the defect.

Next, referring to FIG. 2 and FIG.
6, 17, 18, and 19 will be described in detail.

As shown in FIG. 2, the probe position change amount continuity evaluation means 16 outputs the position signal Yi of the ultrasonic probe 12.
Register 2 for inputting the data in response to the detection of the reflected echo
1, a previous value register 22 for inputting the previous position signal Yi-1; a subtraction circuit 23 for calculating the position change amount | Yi-Yi-1 | between the current time and the previous time; And a comparison circuit 24 for comparing the value with the value ΔY.

Input register 21 and previous value register 2
2 includes the position signals Yi and Yi-1 and the initialization signal R
And a synchronization signal (clock) C, the data is cleared at the start, and the current value signal Yi and the previous value signal Yi−
1 is output to the subtraction circuit 23, and the difference | Yi−Yi−
1 | is required. The obtained difference value is compared with the reference value ΔY in the comparison circuit 24, and when | Yi−Yi−1 |> ΔY, that is, from the probe position at the time of the previous echo detection to the time of the current echo detection, When the amount of change up to the probe position is larger than the fixed value ΔY, a determination signal 101 indicating that each echo belongs to another group (non-continuous) is output.

The beam path continuity detecting means 17
With the detection of the reflected echo, the ultrasonic probe 12 and the reflection source a
Register 2 for inputting a beam path signal Wi between
5, the previous value register 26 for inputting the previous beam path signal Wi-1 and the change amount | Wi of the current and previous beam path.
And a comparison circuit 28 for comparing the amount of change with a constant reference value ΔW.

The input register 25 and the previous value register 26 receive the initialization signal R and the synchronizing signal C together with the beam path signals Wi and Wi-1. , The current value signal Wi and the previous value signal Wi-
1 is output to the subtraction circuit 27, and the difference | Wi−Wi−
1 | is required. Then, the value of the obtained difference is compared with the reference value ΔW in the comparing circuit 28, and when | Wi−Wi−1 |> ΔW, that is, the beam path at the time of the previous echo detection and the current When the difference from the beam path is larger than the fixed value ΔW, a discrimination signal 1 indicating that each echo belongs to another group (non-continuous).
02 is output.

Further, the echo height change amount continuity evaluation means 1
Reference numeral 8 denotes an input register 29 for inputting the echo height signal Hi of the reflected echo obtained by the ultrasonic probe 12, and the respective peak values of the position signal Yi, the beam path signal Wi, and the echo height signal Hi. And a peak value updating comparison circuit 31 for comparing the peak value P (H) of the echo height in the peak register 30 with the echo height signal Hi from the input register 29.
When the current input value Hi is higher than the peak value P (H), Hi becomes the peak value of the new echo height, and this Hi is input to the peak register 30 as an update pulse and temporarily stored. It is supposed to be.

The echo height change amount continuity evaluation means 18 calculates the echo height peak value P
(H) and a subtraction circuit 32 for calculating the difference between the newly input echo height Hi-1 and the difference P (H) -Hi-1 being compared with a reference value .DELTA.H of a constant echo height drop. Comparison circuit 3
3, and outputs the fall signal 103 when P (H) -Hi-1> .DELTA.H.

Further, the echo height change amount continuity evaluating means 18 has a minimum output circuit 34. The minimum output circuit 34 compares the previous value Hi-1 with the previously input echo height Hi-1 and the previous value register 35 which holds the previous value Hi-1. A circuit 36 and a minimum value register 37 for inputting the current value Hi when the current value Hi is equal to or less than the previous value Hi-1 so that the minimum value is always obtained and the minimum value signal 104 is output. Has become.

The minimum value signal 104 and the above-mentioned fall signal 1
03 is input to the AND circuit 38, the discrimination signal 105 is output.

Also, from the peak register 30 described above,
Peak signals 106, 107, 108 indicating respective peak values of the probe position Y, the beam path W, and the echo height H.
Is also output.

The defect evaluation means 19 includes a group memory 39
And a determination circuit 40. Group memory 38
The determination signals 101 to 105 described above are input as a write signal 109 according to a predetermined priority order via the OR circuit 41, and the above-described peak signals 106 to 105
8 is also input and stored. And the group memory 3
8 to the judgment circuit 40, the peak group data signal Gj
(H), Gj (W), and Gj (Y) are output.

The determination circuit 40 determines the position of the reflection source based on the beam path peak group data signal Gj (W) and the probe position peak group data signal Gj (Y), and determines whether the determined position is within a certain area. As shown in FIG. 3, a multiplication circuit 42 and a range comparison circuit 43 for determining the depth position of the reflection source in the material to be inspected, and a probe scanning, as shown in FIG. A multiplication circuit 44, a subtraction circuit 45, and a range comparison circuit 46, which determine the horizontal position along the direction to determine the position, output a defect signal when the reflection source position exists in the set area by the determination in both directions. An AND circuit 47 is provided. The details of the determination will be described later.

Next, the operation will be described with reference to FIGS.

FIG. 4 shows a procedure until a group is determined based on the configuration of FIG.

After the apparatus is started, an initialization process is first performed in the input / output system (steps S1 and S2), and then data is input to the input system (step S3).

As an input system, each register 21 shown in FIG.
22, 25, 26, 29, 35 are the main ones, and the subscript i is set from 0 to each input data Y, W, H (Y: probe position, W: beam path, H: echo height). . The group memory 39 is the main output system.
The subscript j is set from 0.

When data is input, the input register 2
.. And the timing to initialize the peak register 30 and the like are always checked (step S4).
When initialization is performed (YES, illustrated (Y)), i =
Starting from 0 (steps S5 and S6). In this embodiment, the current input value is from i = 1, and i = 0 corresponds to the previous value data.

After the flaw detection operation starts, step S
Since the determination of No. 4 is NO (N in the figure), each calculation stage is entered. In the probe position continuity evaluation means 16, first, the amount of change in the probe position is calculated by the subtraction circuit 23 (step S7), and the difference between the current position (Yi) and the immediately preceding position (Yi-1) is calculated. The absolute value | Yi−Yi−1 | is obtained.

Next, a comparison ΔY ≧ | Yi−Yi−1 | between the obtained change amount and the reference value ΔY is performed (step S).
8). If the change amount is smaller than the reference value (YES),
It is determined that the reflected echoes detected at the current value Yi and the previous value Yi-1 belong to the same common group of the reflection sources, and the flow proceeds to the next beam path change amount calculation step (S9). . That is, in this case, the determination signal 101 of FIG. 2 is not output. Conversely, if the change amount is larger than the reference value (NO), it is determined that the reflected echoes detected at the current value Yi and the previous value Yi-1 belong to different groups having different reflection sources, The discrimination signal 101 of FIG.
Is output and the discrimination signal 1 based on the change in the beam path or the like
02, 105 is input to the group memory 39 of the defect evaluation means 19 (step 16), and thereafter, the process proceeds to calculation of the amount of change at the next position (Yi + 1).

If the determination in step S8 is (YES) and the flow proceeds to step S9 for calculating the variation of the beam path,
First, the absolute value | Wi-Wi-1 | of the difference between the current beam path Wi and the previous beam path Wi-1 is obtained by the subtraction circuit 27.

Next, a comparison Δ between the amount of change and the reference value ΔW
W ≧ | Wi−Wi−1 | is performed (step S1)
0). If the change amount is smaller than the reference value (YES),
It is determined that the reflected echoes corresponding to the current value Wi and the previous value Wi-1 belong to the same group, and the process proceeds to the next echo height comparison step (S11). Also in this case, the determination signal 102 of FIG. 2 is not output. Conversely, if the amount of change is greater than the reference value (NO), the current value Wi and the previous value Wi-
1 is determined to belong to another group, and is input to the group memory 39 (step S16). Thereafter, the next beam path (Wi +
Proceed to 1) change amount calculation.

If the determination at step S10 is (YES) and the routine proceeds to echo height comparison step S11, first, the comparison circuit 31 compares the current echo height Hi with the previous peak value P (H). Hi> P (H) is performed. If this determination is (YES), the peak value of the peak register 30 is updated (step S12), and thereafter, the process proceeds to input of the next value Hi + 1 (step S19).

On the other hand, when the determination in step S11 is (N
In the case of O), that is, when the current value Hi is smaller than the peak value P (H), it is first determined whether or not the previous value Hi-1 is minimal (step S13). This judgment is (N
O), the process proceeds to input of the next value Hi + 1 (step S).
19), if (YES), a head calculation P (H) -Hi-1 from the peak value P (H) for the previous value Hi-1 is performed (step S14), and then the head comparison ΔH ≧ P
(H) -Hi-1 is performed (step S15).

That is, each time a minimum value of the echo height appears, a head difference from the previous peak value is obtained, and by comparing with the reference value, a plurality of peak points included in one envelope are obtained. It is evaluated whether the reflection source is independent.

If the determination in step S15 is (YES), it is evaluated that the reflection source corresponding to the preceding peak point is not independent, and the process proceeds to input of the next value Hi + 1 (step S19).

If the determination in step S15 is (NO), the reflection source corresponding to the preceding peak point is evaluated as independent, and the values of Y, W, and H at that time are stored in the group memory 39 as group data. It is stored (step S16). In this case, when the previous value register initialization signal 110 is input to the previous value registers 22, 26, and 35, the current value data Yi, W is stored in each of the registers 22, 26, and 35.
i and Hi are input and initialization is performed (step S
17), the peak register initialization signal 111 is input to the peak register 30, and the peak register 30 is also initialized (step S18). Thereafter, the process proceeds to the input of the next value Hi + 1 (Step S19).

Thereafter, it is determined whether or not i is the last (step S20). If (NO), data input (step S3) is repeated, and if (YES), the process ends.

By the above operation, it is evaluated that each group of echoes has an independent reflection source. Next, the position of each reflection source is specified, and the defect / non-defect of the reflection source is determined.

FIG. 5 shows the procedure of defect determination based on the determination circuit 40 of FIG. 3, and FIG. 6 shows an example of a defect determination area and the like.

First, a method of setting an area and specifying a position will be described with reference to FIGS.

FIG. 6 shows a sectional shape of a welded portion 11a of a pair of plate materials as the material 11 to be inspected. In this embodiment, the area A where the reflection source a is evaluated as a defect is a range surrounded by a broken line, that is, the depth S (d1
To d2) and a lateral length T (from T0 to T1). If the reflection source a is within the area A, it is evaluated as a defect, and if it is outside the area A, it is evaluated as a non-defect.

When the position of the reflection source a is indicated by coordinates,
The coordinates of the reflection source a are determined by the position Y of the ultrasonic probe 12, the beam path W of the ultrasonic beam 2 emitted from the ultrasonic probe 12, the refraction angle θ, and the like. Can be expressed as

[0075]

(Equation 1) In the above equation, W is the defect evaluation means 19 shown in FIG.
Is obtained from the beam path peak group data signal Gj (W) input to the determination circuit 40, and Y is similarly obtained from the probe position peak group data signal Gj (Y).

That is, in the multiplication circuit 42 of the judgment circuit 40, G
The multiplication of j (W) and cos θ is performed, and the multiplication value, depth d, is input to range comparison circuit 43. The range comparison circuit 43 compares whether the depth d is in the range of d1 to d2.

Further, another multiplication circuit 44 of the judgment circuit 40 multiplies Gj (W) by sinθ, and the multiplication value is subtracted from Gj (Y) by the subtraction circuit 34. And
The subtraction value is input to the range comparison circuit 46, and a comparison T0 ≦ z is made to determine whether the horizontal position z is within the range of T0 to T1.
.Ltoreq.T1 is performed.

As a result of both comparisons, if both the depth and the lateral position are within the area A, a defect signal is output via the AND circuit 47 indicating that the reflection source a is defective.

This procedure is described below with reference to FIG.

After the start, the group memory 39 is first initialized (step S51), and the position of the reflection source is calculated based on Gj (Y) and Gj (W) (step S52).

Next, it is sequentially determined whether or not the obtained position is within the depth S of the area A and the lateral position -T0 to T1 (steps S53 and S54). If either is (NO), the reflection source indicated by Gj is evaluated as not a defect (step S56), and if both are (YES), it is evaluated as a defect (step S5).
5).

After these determinations, a transition to the next group data Gj + 1 (step S57) and a determination as to whether or not to end (step S58) are made, and after all the data have been evaluated, the operation is completed. .

According to the above embodiment, the ultrasonic probe 12
Group determination based on the amount of change in the position, and grouping is performed for each of a plurality of echo groups based on the group determination based on the amount of change in the beam path and the determination of the echo height. It can be seen that there is a reflection source.

Further, the position of the reflection source in the material is clearly grasped as a point by the method of grouping the peak points of the reflection echo, and then the reflection source which becomes a shape echo or other unnecessary echo is excluded as a non-defect. Thus, the test area can be expanded over the entire thickness of the material to be inspected.

Therefore, the distinction between the defect echo and the shape echo can be clearly performed, whereby it is possible to easily and surely determine whether the reflection source is a defect or a non-defect without requiring skill, and to determine whether the defect is defective or not. An accurate depth position from the ultrasonic probe can be detected with high accuracy, and the flaw detection range can be extended over the entire thickness of the material to be inspected.

Further, since it can be effectively used as an automatic ultrasonic flaw detector for welding defect inspection and the like, and does not require a specially complicated image processing mechanism or the like, it can be implemented very easily. become.

[0087]

As described in the above embodiment, according to the present invention, the position of the reflection source in the material is clearly grasped as a point by the method of grouping the peak points of the reflection echo, and the shape is determined. By excluding echoes and other reflection sources that are unnecessary echoes as non-defects, for example, the test area can be set to extend over the entire thickness of the material to be inspected, and the distinction between defect echoes and shape echoes can be clearly determined. This makes it possible to easily and reliably determine whether a reflection source is defective or non-defect without requiring skill, and to determine the exact depth position of the defect from the ultrasonic probe with high accuracy. The effect of being able to detect and expanding the flaw detection range over the entire thickness of the material to be inspected is exhibited.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram according to the embodiment.

FIG. 3 is a circuit diagram of an evaluation unit according to the embodiment.

FIG. 4 is a flowchart showing the operation of the embodiment.

FIG. 5 is a flowchart showing the operation of the evaluation means according to the embodiment.

FIG. 6 is a diagram showing a defect / non-defect discrimination area according to the embodiment.

FIG. 7 is an explanatory diagram showing the principle of the present invention.

8A and 8B are explanatory diagrams showing a conventional example.

FIGS. 9A, 9B, and 9C are explanatory diagrams showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Inspection material 12 Ultrasonic probe 13 Position detector 14 Beam path detector 15 Echo detector 16 Probe position change amount continuity evaluation means 17 Beam path continuity evaluation means 18 Echo height change amount continuity evaluation means 19 Defect evaluation means

Claims (4)

(57) [Claims] An ultrasonic probe is scanned along the surface of a material to be inspected, and echo detection from a reflection source and beam path detection from the ultrasonic probe to the reflection source are synchronously performed with a constant pulse width. The amount of change in the beam path and the amount of change in the echo height from the previous echo detection position are obtained for each echo detection position, and based on each change amount, (1) the current time from the previous echo detection position The amount of change in the beam path to the echo detection position is compared with a certain reference value. If the amount of change in the beam path is smaller than the reference value, a series of successive echo groups is determined to be the same group. (2) When a plurality of peak values are included in a continuous echo group in the case where the same group is set by the operation of (1) based on the variation of the beam path, each peak Compare the change amount of the echo height with the minimum value before and after that with a certain reference value, and when the change amount of the echo height is smaller than the reference value, determine a series of successive echo groups as the same group, The above-mentioned operations (1) and (2) of determining the group as a different group when it is larger are performed, whereby it is evaluated that an independent reflection source exists for each echo group of each group. The position of each reflection source is evaluated as the position in the material to be inspected corresponding to the peak point of the echo height specified based on the position information of the ultrasonic probe and the beam path information, respectively. Ultrasonic testing evaluation method. 2. An ultrasonic probe is scanned along a surface of a material to be inspected to detect an echo from a reflection source, a position of the ultrasonic probe, and a beam from the ultrasonic probe to the reflection source. The path detection is advanced synchronously with a constant pulse width, and for each echo detection position, the amount of change in the position of the ultrasonic probe, the amount of change in the beam path, and the amount of change in the echo height from the previous echo detection position are respectively determined. (1) comparing the position change amount of the ultrasonic probe from the previous echo detection position to the current echo detection position with a fixed reference value, and calculating the position change amount from the reference value. If it is smaller, a series of successive echo groups is determined to be the same group, and if it is larger, it is determined to be another group. (2) The same group is operated by the operation (1) based on the amount of position change of the ultrasonic probe. The last time -The change amount of the beam path from the detection position to the current echo detection position is compared with a fixed reference value, and if the change amount of the beam path is smaller than the reference value, a series of successive echo groups is determined to be the same group, If it is larger, it is determined to be another group. (3) When the same group is formed by the operations (1) and (2) based on the amount of change in the position of the ultrasonic probe and the amount of change in the beam path, continuous When multiple peak values are included in the echo group, the amount of change in the echo height between each peak value and the local minimum value before and after the peak value is compared with a fixed reference value, and the amount of change in the echo height is determined as a reference. When the value is smaller than the value, a series of continuous echo groups is determined to be the same group, and when the value is larger, the group is determined to be another group, and the above-described operations (1) to (3) are performed.
Evaluate that there is an independent reflector for each echo group of each group, and determine the position of each reflector based on the position information and beam path information of the ultrasonic probe. An ultrasonic flaw detection evaluation method characterized by evaluating a position in a material to be inspected corresponding to a height peak point. 3. The ultrasonic flaw detection evaluation method according to claim 1, wherein when it is determined that the reflection source is within a certain area in the material to be inspected, the reflection source is evaluated as a defect, When the reflection source is determined to be out of the area, it is evaluated as a non-defect. 4. An ultrasonic probe scanned along a surface of a material to be inspected, a position detector for detecting a position of the ultrasonic probe, and detecting an echo height from a reflection source. An echo detector, a beam path detector for detecting a beam path from the ultrasonic probe to a reflection source, and a position signal output from the position detector, and a previous echo detection is performed for each echo detection position. The position change amount of the ultrasonic probe from the position is obtained, and the position change amount is compared with a certain reference value. If the change amount is smaller than the reference value, both echoes belong to the same reflection source in the same group, If the value is larger than the value, the probe position change amount continuity evaluation means for setting both echoes to non-identical groups belonging to different reflection sources, and a beam path signal output from the beam path detector are input, and each echo is detected. Previous eco for each position -Calculate the amount of change in the beam path from the detection position, compare the amount of change in the beam path with a certain reference value, and if smaller than the reference value, assign both echoes to the same group belonging to the same reflection source, the reference value If it is larger, the beam path change amount continuity evaluation means for setting both echoes to non-identical groups belonging to different reflection sources, and an echo signal output from the echo detector, and When a plurality of peak values are included, the amount of change in echo height from each peak value to the subsequent minimum value is obtained, and each of the echo height changes is compared with a fixed reference value, and the When the echo height is smaller than the reference value, both echoes are in the same group belonging to the same reflection source, and when larger than the reference value, both echoes are in the non-same group belonging to different reflection sources. And sex evaluation means,
The continuity evaluation signal from each of these evaluation means is input, and for each group, the reflection in the material to be inspected is determined based on the position information and beam path information of the ultrasonic probe corresponding to the peak value of the echo height. Defect evaluation means for determining the position of the source, evaluating the defect as a defect when the reflection source is within a certain area in the inspection target material, and evaluating as a non-defect when the reflection source is outside the same area. An ultrasonic flaw detection evaluation device characterized by the above-mentioned.