JP2006322900A - Ultrasonic inspecting method and ultrasonic inspecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic inspecting method and an ultrasonic inspecting apparatus, capable of simply and precisely measuring a height of a defect such as an aperture crack or the like on the rear surface of a welded zone in a stainless steel. <P>SOLUTION: An oscillator 11 operating in a longitudinal wave oblique angle probe 10 is moved along a surface of a test object 100 in a direction of a plane carrying a transmission wave. Then, a B-scope image of a reception signal is displayed on a coordinate having axes of a probe position and a reception time or corresponding units, such that an image of a longitudinal wave, a transversal wave, a mode transformed wave and a creeping wave represents their trajectories. Reflection paths and reflection sources corresponding to above wave kinds are specified from relative positional relations of respective trajectories, and a position and a size of the defect are presumed. For example, in the case of the defect which is in communication with the bottom of the test object, the size of the defect is determined from appearances of the creeping wave, the mode transformed wave and the longitudinal wave or the transversal wave from the head edge section of the defect. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic test method and an ultrasonic test apparatus that can easily detect cracks and the like in welded portions of austenitic stainless steel.

Conventionally, ultrasonic testing of austenitic stainless steel welds is known to have poorer ultrasonic transmission than ferritic steel and poor applicability for defect detection and defect height (depth) measurement. . As a conventional defect sizing method, for example, the following method is used as described in Non-Patent Document 1. B) A harmful defect is detected with a shear wave oblique angle probe. B) If the presence of cracks is suspected, use a creeping wave probe to check for cracks from the back of the specimen (the opposite side where the probe is scanned). C) Using a creeping wave probe, roughly classify the size of cracks (large, medium, and small). D) With reference to the classification results of the crack size, the height (depth) of the crack can be measured by a) the edge echo method, b) the TOFD method, or c) the phased array method alone or in combination. It is used. Further, as in Patent Document 1, a test method using the maximum value of the end echo is known.
JEAG 4207-2004 “Guidelines for ultrasonic testing in in-service inspection of equipment for light water nuclear power plants” JP-A-11-248690

  These methods have the following problems. B) It is necessary that the engineer performing the test is familiar with many techniques such as the creeping wave probe method, the end echo method, the TOFD method, and the phased array method. B) The TOFD method cannot be applied when there is noise from the weld. C) In the end echo method and the phased array method, it is difficult to distinguish the signal from the tip of the defect and the signal other than the tip, and the measurement results differ depending on the subjectivity of the inspector. D) Since the measurement results differ depending on the subjectivity of the inspector, there are large variations in measured values.

  An object of the present invention is to provide an ultrasonic test method and a test apparatus capable of easily and accurately measuring the height of a defect such as a back surface opening crack in a stainless steel welded portion.

  In order to achieve the above object, the ultrasonic test method according to the present invention is characterized in that a transducer on which a longitudinal wave oblique angle probe operates moves in the direction of a plane to which a transmission wave belongs along the surface of the specimen, thereby Received at coordinates with probe position and reception time or equivalent unit (hereinafter referred to as “reception time”) as axes so that images by waves, transverse waves, mode conversion waves and creeping waves are displayed as trajectories The B scope image of the signal is displayed, the reflection path and the reflection source corresponding to the type of wave are identified from the relative positional relationship of each locus, and the position and size of the defect are estimated.

  Here, in order to move the transducer, an aspect of “moving the longitudinal wave oblique angle probe to move the activated transducer along the surface of the specimen in the direction of the plane to which the transmission wave belongs” is provided. is there. Further, “the vibrator is composed of a plurality of columnar vibrators, and the vibrator to be operated is switched in the columnar vibrator to operate the vibrator in the direction of the plane to which the transmission wave belongs. It may be moved along the surface.

  In the case where the defect communicates with the bottom of the specimen, the size of the defect may be determined based on how the creeping wave, the mode conversion wave, and the transverse wave or longitudinal wave appear from the tip of the defect.

  Further, the probe position and the reception time are obtained from the trajectory of the transverse wave and the longitudinal wave generated from the same defect portion, respectively, and the coordinates of the same defect portion are obtained from the relationship between the two sets of probe positions and the reception time. Also good.

  Further, according to the present invention, the defect communicates with the bottom of the specimen, and the probe position and the reception time are obtained from the locus of the creeping wave, and the position of the defect portion on the bottom is obtained. is there.

  Among the defects, the probe position and the reception time are obtained from a plurality of points of the trajectory of the mode-converted wave generated from the intermediate part, respectively, and the intermediate defect is obtained from the geometric relationship such as the plurality of sets of probe positions and the reception times. It is characterized by obtaining the coordinates of the part.

  In each of the above characteristics, the probe position and the reception time are obtained from at least two points on the trajectory of the longitudinal wave generated from the same defective portion, and the same from the relationship between the two or more sets of probe positions and the reception time. You may obtain | require the coordinate of a defect part.

  Furthermore, a method of imaging the defect by displaying the coordinates of the defect portion obtained by each of the above methods in two-dimensional coordinates may be adopted.

  The present invention also provides a longitudinal wave oblique angle probe, an encoder for recording coordinates in a state in which the probe is moved along the surface of the test body in the direction of the plane to which the transmission wave belongs, and the probe. The probe position and the reception time or this so that the image by the longitudinal wave, the transverse wave, the mode conversion wave and the creeping wave is displayed when the probe is moved in the direction of the plane to which the transmission wave belongs. And a display device that displays a B-scope image of a received signal at coordinates having a unit (hereinafter, “reception time etc.”) as an axis.

  In addition, other features of the ultrasonic testing apparatus used in the above-described method of the present invention include a rolling mechanism that rolls on the surface of the test body, a pair of rollers whose rotation axes that roll along the surface of the test body are orthogonal to each other, and each of these. An encoder associated with the roller, and a groove is formed on the surface of each roller in a direction along the rolling axis of each roller. When one of the rollers rolls, the other grooves allow sliding along the grooves, and the straightness by rolling improves, so that the position can be easily identified. Here, the rolling mechanism may include an arm that is swingably attached to the casing one by one in front and rear and a ball at the tip thereof, and may include a centering mechanism that synchronizes the inclination of the pair of arms 44. This feature makes it possible to accurately follow pipes of various diameters.

  In addition, another feature of the ultrasonic testing apparatus used in any of the ultrasonic testing methods described above is that the relative positional relationship between the trajectories is specified by designating the trajectory of the B scope image with a cursor. is there.

According to the above feature of the present invention, the B scope image of the received signal is displayed, the reflection path and the reflection source corresponding to the type of wave are identified from the relative positional relationship of each locus, and the position and size of the defect. Estimate. Therefore, it is possible to provide an ultrasonic test method and a test apparatus that can easily and accurately measure the height of a defect such as a crack opening on the back surface of a stainless steel weld.
Other objects, configurations and effects of the present invention will become apparent from the following description of the best mode for carrying out the invention.

  Next, the first embodiment and examples of the present invention will be described with reference to FIGS. As shown in FIG. 1, the ultrasonic testing method in the present invention is a single probe oblique angle method using a longitudinal wave oblique angle probe 10 called a creeping wave probe. The probe 10 causes the transverse wave ultrasonic wave S and the longitudinal wave ultrasonic wave L to enter the test body 100. The position detector 20 works with the probe 10 to detect the spatial position of the probe 10. The transmission / reception device 30 connected to the probe 10 and the position detector 20 includes a CPU 31, a transmission unit 32, a reception unit 33, a position detection unit 34, a display unit 35, and a signal processing unit 36.

  A transmission signal generated by the transmission unit 32 is input to the probe 10, a plurality of types of ultrasonic waves received as echoes in the test body 100 are input to the reception unit 33, and arithmetic processing is performed by the signal processing unit 36 and the CPU 31. Yes. Further, the position data of the probe 10 is obtained by inputting a signal from the position detector 20 to the position detector 34 and performing arithmetic processing by the signal processor 36 and the CPU 31. FIG. 2 shows data displayed on the display unit 35 and data that has been arithmetically processed by the CPU 31.

  In the ultrasonic testing method according to the present embodiment, the probe 10 has a single transducer 11 attached to a wedge 12. Then, the position detector 20 is attached to the probe 10, the specimen 100 is scanned in the front-rear direction with respect to the defect D, the position signal of the probe 10 sent from the position detector 20, and the probe A B scope image is obtained from a plurality of types of ultrasonic signals received at 10. When the probe 10 is scanned on the test body 100 as shown in FIG. 1, B scope image examples shown in FIGS.

  As shown in FIG. 3A, signals from defects due to the longitudinal wave L, the transverse wave S, the mode conversion wave M, and the creeping wave C are displayed on the B scope as trajectories. 3 and 4, L is a longitudinal wave, S is a transverse wave (including creeping wave), M is a mode conversion wave, 1 is a defect tip, 2 is a defect bottom, a is a defect right side, and b is The left side of the defect is shown, and so on. FIG. 4A shows the positional relationship between each locus in the image example shown in FIG. 3A and the reflection source (defect D). The example of Fig.4 (a) is an example of an image in the case of the defect D having a wide tip, and corresponds to the shape of the poor penetration of the welding defect. Note that the vertical wave L and the horizontal wave S have different propagation speeds, and therefore display positions thereof are different.

  On the other hand, when the width of the groove becomes narrower, the loci L1b and S1b from the left tip shown by the broken line and the loci L1a and S1a from the right tip shown by the solid line approach each other. When the width is narrow like the tip of a crack, the trajectories shown by the broken line and the solid line in FIG. 3A match, and L1a and S1a are as shown in FIG. 3B and FIG. 4B. appear. From the comparison of the images shown in FIGS. 4A and 4B, various methods for measuring the height of the defect D (crack) are possible.

Next, the measurement method in this embodiment will be described.
A B-scan image is taken at the position of the defect D of the test body 100 suspected of cracking the back surface opening. First, for example, the probe 10 is placed in the vicinity of an expected defect D position, scanning is performed in a direction away from the defect D, and scanning is performed until the echo at the groove bottom due to the longitudinal wave L disappears.
The scanning range is 0.5 skip transverse wave S position> probe 10 position> 0.5 skip longitudinal wave L position, data collection range (time axis): in the range longer than ultrasonic wave propagation time 0 μsec to 0.5 skip longitudinal wave L propagation time The range is such that the signal at the bottom of the defect D due to the longitudinal wave L disappears.

  And the presence or absence of a back surface opening crack and the large, medium, and small classification of a crack are performed. Classification may be performed from the pattern of the A scope image of the conventional method (appearance pattern of reflected echo from the defect D), but based on the appearance position of the locus from the tip of the defect D (crack) of the B scope image. May be. (See Figure 26)

The sizing method of the crack height from the B scope image is as follows.
(1) From the relative position of each trajectory obtained in the B scope image, the defect D (crack tip, crack bottom, middle part) and ultrasonic path (longitudinal wave L, transverse wave S, mode conversion wave M, creeping wave C) (See FIG. 25)
(2) Application of analysis method The method for obtaining the crack height is as follows.
a) When signal by transverse wave S is obtained b) The position of the crack tip is obtained by the intersection method of transverse wave S and longitudinal wave L.
B) The position of the middle part of the crack is obtained by the mode conversion wave method. C) The bottom part of the crack is obtained by the intersection method of the transverse wave S and the longitudinal wave L. The creeping wave C may be obtained.
When the signal of the mode conversion wave M cannot be obtained due to a small defect, steps a) and c) are performed.
b When the signal of the transverse wave S cannot be obtained When there is a surplus in the welded part and the probe 10 cannot approach the defect D side. Or when the transverse wave S attenuate | damps in a welding part and a signal is not acquired, it is based on the following method.
B) The position of the crack tip is determined by the intersection method of longitudinal waves L.
B) The position of the middle part of the crack is obtained by the mode conversion wave method.
C) Obtained by creeping wave method.
If a mode-converted wave signal cannot be obtained due to a small defect, perform steps a) and c) above. Hereinafter, each measurement method will be described in detail.

First measurement example: Crack height measurement method at the intersection of longitudinal wave L and transverse wave S Analysis method when the signal at the tip of the defect D (crack) is obtained in both the longitudinal wave L path and the transverse wave S path 5 to 6 show. FIG. 5 shows the locus used for the analysis with a solid line. In FIG. 5, data having the symbol S indicates data obtained by the transverse wave, and data having the symbol L indicates the data obtained by the longitudinal wave.
(A) Analysis method procedure 1 by drawing (Figure 5)
As illustrated in FIG. 5, the ultrasonic wave propagation times of the defect tip L1a and the defect bottom L2a in the longitudinal wave L and the ultrasonic wave propagation times of the defect tip S1a and the defect bottom S2a in the transverse wave S are measured from the respective probe positions. Ask.
Step 2

ここで、T_O：超音波伝ぱ時間（探触子くさび内伝ぱ時間を含む）
T_W：くさび内伝ぱ時間（往復）
VL：試験体中の縦波音速
Vs：試験体中の横波音速
LL：縦波伝ぱ距離（片道）
LS：横波伝ぱ距離（片道） The ultrasonic propagation distance LL at the longitudinal wave L and the ultrasonic propagation distance LS at the transverse wave S in the test body 100 are obtained from the equations (1) and (2).

Where T _O : Ultrasonic propagation time (including propagation time in the probe wedge)
T _W : Propagation time in the wedge (round trip)
VL: Longitudinal wave velocity in the specimen
Vs: Transverse sound velocity in the specimen
LL: Longitudinal wave propagation distance (one way)
LS: Yokonami propagation distance (one way)

Step 3 (Figure 6a)
As shown in FIG. 6a, a circle is drawn with the propagation distance of the ultrasonic wave calculated from the ultrasonic wave propagation time in the test body 100 at each probe position as the radius, and the intersecting points become the tip and bottom of the defect. .
In FIG. 5, the probe positions YS1, YL1, and YL2 for obtaining the propagation time may be selected at clear positions in the image, and there is no need to obtain the peak position as in the conventional end echo method. The position of YS2 uses the image position on the side where the ultrasonic propagation time is short. When the propagation time is longer, the creeping wave propagation time is added to the transverse wave, so the creeping wave analysis method described later is used.

(B) In the case of analysis by calculation (FIG. 6b)
If the radius of the circle is Ra and Rb and the distance between the circle centers A and B is L from Fig. 6b, the coordinates (Px, Py), (Qx, Qy) of the intersection of the circles are as follows: Can be sought.

  The intersection of the circles in the test body 100 is obtained by a negative sign (−) in the equations (5) and (6). This analysis method based on drawing or calculation does not use the refraction angle of the probe 10, and therefore has an advantage that there are fewer factors of error than the end echo method used conventionally. In the conventional phased array method and edge echo method, the subjectivity of the flaw detector enters when the peak echo position of the defect tip is obtained. Since this measurement example does not need to obtain the peak position, it has an advantage that there is no error due to the subjectivity of the flaw detector. Since the echo from the defect tip and the echo position from the bottom of the defect can be identified on the image from the relationship with other echoes, the stage of identifying the defect tip echo as in the conventional phased array method or edge echo method It has the advantage that it will not be mistaken.

Second Measurement Example: Method for Measuring Position of Cracked Bottom by Creeping Wave In addition to the first measurement example, the position of the bottom of the defect D can be obtained by analyzing the creeping wave C. The condition that the path of the ultrasonic wave including the creeping wave C is the shortest is obtained from FIG. The propagation time T when the ultrasonic wave travels along the path ABC can be obtained by the following equation, where V1 is the transverse wave velocity and V2 is the longitudinal wave velocity.

（5）式をxで微分すると

ｆ’（ｘ）＝0のときにＴは最小となるので

（10）式を整理すると

(5) Differentiating the equation by x

T is minimum when f '(x) = 0

(10) When organizing the formula

When the transverse wave velocity of austenitic stainless steel is 3100 m / sec and the longitudinal wave velocity is 5790 m / sec, θ ₁ = 32.37 °. What is necessary is just to observe after the shortest propagation time when analyzing the waveform of the creeping wave C. The transverse wave refraction angle θ ₁ when the propagation time of the ultrasonic wave is the shortest in the path including the creeping wave C is expressed by the equation (11), but the image is formed in the path in the center of the beam with the highest sound pressure. , propagated in transverse refraction angle of probe theta ₁ of FIG. 7, travels between BC and mode converted to a longitudinal wave L in the test body surface. The wave reflected from the bottom of the defect D returns between the CBs as a longitudinal wave L, and a wave converted to a transverse wave S at the position B passes through the BA and returns to the probe 10. An image used for analysis of the creeping wave C is shown by a solid line in FIG.

(A) Analysis procedure procedure 1 by drawing (Figure 8)
As shown in FIG. 8, the ultrasonic propagation time at each probe position is obtained.
Step 2 (Figure 9)
A straight line is drawn from the probe position to the inner surface of the specimen at the transverse wave refraction angle (θs) of the probe used. (Dashed line in FIG. 9)

ここで、T_O：超音波伝ぱ時間（探触子くさび内伝ぱ時間を含む）
T_W：くさび内伝ぱ時間（往復）
T_S：横波伝ぱ時間（往復）

ｔ：試験体の厚さ
V_S：横波音速 Step 3
Calculate propagation time T _C to and fro with creeping wave.

Where T _O : Ultrasonic propagation time (including propagation time in the probe wedge)
T _W : Propagation time in the wedge (round trip)
T _S : Propagation time (round trip)

t: thickness of specimen
V _S : shear wave speed

Step 4 (Figure 10)
The creeping wave propagation distance (one way) L _C is obtained, and a circle with a radius L _C is drawn around the intersection of the inner surface of the specimen and the broken line.

Step 5 (Fig. 11)
Repeat step 1 to step 4.
The intersection of the circle and the inner surface is the position of the reflection source, but the reflection source position is concentrated at one point as shown in FIG. Thereby, the validity of the analysis method can be confirmed.

In the case of analysis by calculation, the horizontal distance YF from the probe position to the reflection source is obtained by the following equation.

Third Measurement Example: Method for Measuring Defect D Position Using Mode-Converted Wave A reflection source at the intermediate portion between the tip of the defect D and the bottom of the defect can be obtained from the path of the mode-converted wave. In FIG. 12, the path of the mode-converted wave M is transmitted along AB between the transverse waves S, BE, and EA using the longitudinal wave L. Consider θ1 and θ2 when the mode conversion wave M propagates in the shortest time. As shown in FIG. 12, when considering a line segment EF obtained by inverting AE with the CE axis, the BEF becomes a straight line when propagating the BEA path in the shortest time. Therefore, θ1 and θ2 that minimize the total time T when traveling between AB at the transverse wave velocity V1 and between BF at the longitudinal wave velocity V2 may be obtained.

(16)式をｘで微分すると

ｆ’(x)＝0のときにTが最小となるので

(18)式を整理すると

Differentiating equation (16) by x

T is minimum when f '(x) = 0

(18)

Equation (19) is the same as Snell's law. That is, in the path through which the mode conversion wave M propagates in the shortest time, θ1 and θ2 satisfy Snell's law. In the equation (19), when θ ₂ = 90 °, the equation is the same as the equation representing the shortest propagation path of the creeping wave C in the equation (11). The calculation of θ1 and θ2 from the relationship between the propagation time of the mode converted wave path and the equation (19) is based on numerical calculation. In actual flaw detection, it is necessary to consider that the defect signal is obtained by the spread of ultrasonic waves without satisfying the equation (19). FIG. 13 shows a mode-converted wave path with the incident angle of the transverse wave fixed, and the position on the ellipse shown in FIG. 13 is a possible reflection source position. In FIG. 13, path 2 satisfies the Snell relationship by mode conversion on the bottom surface. Route 3 is a route where the BEF is a straight line. Path 5 is a path equal to the longitudinal wave refraction angle of the probe. Consider the echo height of each path in FIG. Since the echo height (h) of each path of the mode-converted wave is proportional to the product of the directivity of the ultrasonic wave and the reflection loss at the interface, it is expressed by equation (20).

  From the calculation result of equation (20), the path 3 in FIG. 13 (the path in which the BEF is a straight line in FIG. 12) is the path with the highest echo height, and the angle at which the ultrasonic wave is incident on the defect surface and the angle at which it is reflected are This is the case. FIG. 13 shows a case where the incident angle of the transverse wave S is fixed, and the incident angle can be changed. FIG. 14 shows an example in which the refraction angle of the transverse wave S is changed, and there is no significant difference between the case of drawing with the transverse wave refraction angle of the probe and the case of changing the angle of the transverse wave S. Therefore, the path of the mode converted wave M can be represented by a method using the transverse wave refraction angle of the probe.

(A) Analysis method of reflection source position of mode conversion wave M by drawing (in case of defect D without inclination)
The image used for the analysis of the mode conversion wave is shown by the solid line in FIG. In the analysis of the mode conversion wave, an analysis of a defect Da having no inclination (defect extending in a direction perpendicular to the surface of the specimen) and a defect Db having an inclination is considered. Whether or not the defect is inclined can be known from the result of obtaining the defect tip position and the defect bottom position.

Step 1 (Figure 15)
As shown in FIG. 15, the ultrasonic propagation time at each probe position is obtained.
Step 2 (Figure 16)
A straight line is drawn from the probe position to the inner surface of the specimen at the transverse wave refraction angle (θs) of the probe used. (Dashed line in Fig. 16)

ここで、T_O：超音波伝ぱ時間（探触子くさび内伝ぱ時間を含む）
T_W：くさび内伝ぱ時間（往復）
T_S：横波伝ぱ時間（片道）

ｔ：試験体の厚さ
V_S：横波音速 Step 3
Calculate the propagation time _TL of the longitudinal wave of the mode conversion wave.

Where T _O : Ultrasonic propagation time (including propagation time in the probe wedge)
T _W : Propagation time in the wedge (round trip)
T _S : Yokonami propagation time (one way)

t: thickness of specimen
V _S : shear wave speed

Step 4 (Fig. 17)
The propagation distance L _L of the longitudinal wave of the mode conversion wave is obtained, a circle with a radius L _L is drawn around the point R ₁ , and a point that intersects the surface of the specimen is Q ₁ and R ₁ Q ₁ is connected by a straight line.

Step 5 (Figure 18)
A straight line CC ′ that bisects one line segment P ₁ Q ₁ vertically is drawn, and a point that intersects the straight line R ₁ Q ₁ is defined as S ₁ .
2 P ₁ R ₁ S ₁ P ₁ is the path of the mode conversion wave.

Step 6 (Figure 19)
Repeat step 1 to step 5 for each probe position and ultrasonic propagation time.

ここでθ1は探触子の横波屈折角、θ₂は(19)式のL_L（図12のBFの長さ）から次式で求める。

図12より、探傷面から反射源までの深さｄは次式で求める。

(B) Analysis of mode conversion wave by calculation (in the case of defect Da without inclination) (FIG. 12)
From FIG. 12, the horizontal distance Y _F from the probe position to the reflection source is obtained by the following equation.

Here θ1 is obtained transverse refraction angle of the probe, theta ₂ from equation (19) L _L (the length of the BF in FIG. 12) by the following equation.

From FIG. 12, the depth d from the flaw detection surface to the reflection source is obtained by the following equation.

  Analysis by mode conversion gives the position of the center of the defect in the case of a large defect. In some cases, the position of the tip of the defect may be obtained for the medium defect, but when the information on the tip of the defect by the longitudinal wave L is obtained, the analysis result by the longitudinal wave L is given priority. Whereas the conventional end echo method tries to obtain the position information of the tip and bottom of the defect, the present method adds the information of the center of the defect, so the reliability of the analysis is improved.

(C) Analysis of mode conversion wave by drawing (in case of tilted defect)
Procedures 1 to 3 are the same procedure as for a defect with no inclination.
Step 1 (Figure 15)
As shown in FIG. 15, the ultrasonic propagation time at each probe position is obtained.
Step 2 (Figure 16)
A straight line is drawn from the probe position to the inner surface of the specimen at the transverse wave refraction angle (θs) of the probe used. (Dashed line in Fig. 16)

ここで、T_O：超音波伝ぱ時間（探触子くさび内伝ぱ時間を含む）
T_W：くさび内伝ぱ時間（往復）
T_S：横波伝ぱ時間（片道）

ｔ：試験体の厚さ
V_S：横波音速 Step 3
Equations (27), (28), and (29) are the same as equations (21), (22), and (23). Calculate the propagation time _TL of the longitudinal wave of the mode conversion wave.

Where T _O : Ultrasonic propagation time (including propagation time in the probe wedge)
T _W : Propagation time in the wedge (round trip)
T _S : Yokonami propagation time (one way)

t: thickness of specimen
V _S : shear wave speed

Procedure 4 Determining Defect Inclination Defect inclination is determined by the method shown in Example 1 and the like, since the coordinates of the tip of the defect and the coordinates of the bottom of the defect Db are obtained.

次に図20の(a)に示すように点P1を通り欠陥Ｄｂの傾き角αの直線を引き、円と交わる点をQ₁としてR₁Q₁を直線で結ぶ。欠陥Ｄｂの傾き角が−αの場合は図20の(b)に示すように点Pを通り−αの傾きで直線を引き、円と交わる点をQ₁としてR₁Q₁を直線で結ぶ。 Step 5 (Figure 20)
Obtains the propagation distance L _L in the longitudinal waves L mode converted waves, a circle with a radius L _L around the point R _1. L _L can be calculated from equation (29).

Next, as shown in FIG. 20 (a), a straight line having the inclination angle α of the defect Db passing through the point P1 is drawn, and a point intersecting with the circle is defined as Q ₁ and R ₁ Q ₁ is connected by a straight line. When the inclination angle of the defect Db is −α, a straight line is drawn with the inclination of −α passing through the point P as shown in FIG. 20B, and the point intersecting with the circle is defined as Q ₁ and R ₁ Q ₁ is connected by the straight line. .

Step 6 (Figure 20)
A straight line CC ′ that bisects the line segment P ₁ Q ₁ vertically is drawn, and a point that intersects the straight line R ₁ Q ₁ is defined as S ₁ . P ₁ R ₁ S ₁ P ₁ is the path of the mode conversion wave.

Step 7 (Figure 21)
Repeat step 1 to step 65 for each probe position and ultrasonic propagation time.

ここでθｓは横波Ｓの屈折角、αは欠陥の傾き角である。欠陥の傾き角が−αのときは

となる。 (D) Analysis of mode-converted wave by calculation (in case of tilted defect) (Fig. 22)
From FIG. 22, when the auxiliary line of the thickness t ₁ of the test specimen is drawn, d1 and YF1 can be obtained in the same manner as in the case of the defect Da having no inclination. The depth d of the reflection source position S and the horizontal distance YF between the probe and the reflection source can be obtained from d1 and YF1 and the inclination angle α of the defect. From Figure 22,

Here, θs is the refraction angle of the transverse wave S, and α is the inclination angle of the defect. When the tilt angle of the defect is -α

It becomes.

縦波Ｌでの超音波の伝ぱ距離R₁Q₁の長さL_Lは（29）式より求まるのでθ2は次式で表される。

ここでT₁＝Ls×COSθ₁となる。したがって、YF1およびｄ1は次式で求められる。

以上から反射源位置の深さｄおよび探触子１０からの水平距離YFは

と書ける。欠陥Ｄｂの傾き角が−αのときは

となる。 Next, when obtaining the length L _S of the propagation distance P ₁ R ₁ of the ultrasonic wave in the transverse wave S,

Since the length L _L of the propagation distance R ₁ Q ₁ of the ultrasonic wave in the longitudinal wave L is obtained from the equation (29), θ 2 is expressed by the following equation.

Here, T ₁ = Ls × COSθ ₁ . Therefore, YF1 and d1 are obtained by the following equations.

From the above, the depth d of the reflection source position and the horizontal distance YF from the probe 10 are

Can be written. When the inclination angle of the defect Db is −α

It becomes.

Fourth Measurement Example: Longitudinal Intersection Method Using Creeping Wave Probe The position of the defect tip can also be obtained using a reflection image from the tip of the defect D by the longitudinal wave L. The image used is shown by the solid line in FIG.
Analysis procedure by drawing

Step 1 (Figure 23)
As shown in FIG. 23, the ultrasonic propagation time at each probe position is obtained.
Step 2 (Figure 24)
A circle is drawn with the propagation distance of the ultrasonic wave calculated from the ultrasonic wave propagation time in the specimen at each probe position as the radius, and the intersection point becomes the tip of the defect. The bottom of the defect D is obtained in the same manner as in the case of the tip of the defect D using the trajectory from the bottom of the defect D by the longitudinal wave L. The probe positions YL1 and YL2 for obtaining the propagation time in FIG. 23 may be selected at clear positions in the image, and there is no need to obtain the peak position as in the conventional end echo method. The analysis by calculation uses the method of obtaining the intersection of the circles of Equations (3) to (6).

  In FIG. 25, the flowchart of the measuring method of this invention is shown. By scanning the probe 10, a B scope image is obtained, and the size of the defect D is determined, whereby a measurement method (first measurement example to fourth speed example) according to the size of the defect is performed. select. When determining the size of the defect D, the B scope image shown in FIG. 2 is subjected to image processing, and image recognition means such as pattern matching is employed to automatically determine the size of the defect D using computer software. It is also possible to identify and automatically select a measurement method according to the size. In this case, an appropriate one of the measurement methods (first to fourth measurement examples) may be automatically selected as appropriate, and the above algorithm may be operated to automatically calculate the position and size of the defect D.

  An example is shown in FIGS. FIG. 26 shows the measurement results based on the difference in the size of the defect D. The height of the defect D can be accurately measured using the methods of the first measurement example to the fourth measurement example alone or in combination. FIG. 27 shows a result of applying the present invention to a welded part of austenitic stainless steel in which fatigue cracks are inserted. The measured values according to the present invention are in good agreement with the production values of the inserted fatigue cracks. In this method, not only the analysis method by drawing can be used, but also the size of the defect can be obtained by calculation. As shown by the symbol Pxy in FIG. 2, the cursor for scanning the point on the locus of the obtained image with the mouse By clicking the button, it is possible to automatically calculate the crack height or display the crack as a calculation result as an image. In the mode of FIG. 2, as indicated on the lower tag, “defect tip due to longitudinal wave”, “defect tip due to transverse wave”, “defect center due to mode conversion”, “defect bottom due to creeping wave” Each can be selected.

  Next, another embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the member similar to previous 1st embodiment.

  28 to 30 show other embodiments of the probe 10 and the position detector 20. The ultrasonic flaw detector 40 in this embodiment is generally provided with a casing 41, four arms 44, a probe 10, a probe holder 48, and a position detector 20. The casing 41 is small and has a size that fits in the palm of the hand, and is easy to handle.

  The arms 44 are swingably attached to the casing 41 in pairs with the gear 43 via the shaft 43a. A ball 44 a for rolling the surface of the test body is attached to the tip of each arm 44. The gear 43 meshes with each other before and after the casing, and constitutes an alignment mechanism 42 that synchronizes the inclination of the pair of arms 44 so as to correspond from a small diameter pipe to a flat surface. The alignment mechanism 42, the arm 44, and the ball 44a constitute a rolling mechanism.

  The probe holder 48 elastically connects the base portion 48a on the casing 41 side and the swinging portion 48c with a hinge 48b. A holding portion 48e for holding the probe 10 is connected to the swing portion 48c by a shaft 48d. Due to the probe holder 48, the probe 10 always contacts the surface of the specimen at the same angle.

  The position detector 20 includes x and y direction rollers 45a and 45b fixed to a roller holder 47 that swings around a receiving shaft 47a, and x and y direction encoders 46a and 46b. The x-direction roller 45a processes a surface groove along the y-axis so as not to slip when scanning in the x-direction. Further, this groove has an effect of reducing the resistance when scanning in the y direction. The x-direction encoder 46 a sends the movement distance of the position detector 20 when scanning in the x direction to the position detection device 34. The y-direction roller 45b has a surface groove along the x-axis so as not to slip when scanning in the y-direction. Also, this groove has an effect of reducing resistance when scanning in the x direction. The y-direction encoder 46 b sends the movement distance of the position detector 20 when scanning in the y direction to the position detection device 34. In the roller receiving shaft 47, the x-direction roller 45a and the y-direction roller 45b perform seesaw motion around the receiving shaft 47a to ensure the copying property to the test body 100.

In the test, the probe holder 48 is grasped and the probe 10 is pressed against the test body 100 and moved in the x and y directions. In addition to the structure as shown in FIGS. 28 to 30, the ultrasonic flaw detector 40 for achieving this method may be a mechanism that has a guide rail, for example, and can scan the probe 10 in the XY directions. It may be one that can detect the position with ultrasonic waves or infrared rays.
FIG. 31 shows the possibility of another embodiment for measuring the height of surface opening cracks and internal cracks. FIG. 31A shows a method for measuring the height of surface opening cracks in the test body 100, and by measuring the longitudinal wave L and the transverse wave S, the height of the defect D can be measured. Presumed. FIG. 31 (b) shows a method for measuring the height of the internal crack of the test body 100, and it is estimated that the height of the defect D can be measured by measuring the longitudinal wave L and the transverse wave S. Is done.

  In the above-described embodiment, the configuration is such that “the moving transducer is moved along the surface of the specimen in the direction of the plane to which the transmission wave belongs” by moving the longitudinal wave oblique angle probe. However, as shown in FIG. 32, “the vibrator is composed of a plurality of columnar vibrators 11 ′, and the vibrator (11a that operates by switching and operating the vibrator to be operated in the columnar vibrator 11 ′”). , 11b, 11c... May be moved along the surface of the specimen 100 in the direction of the plane to which the transmission wave belongs.

  Although this technique is intended for defects such as back surface opening cracks in austenitic stainless steel welds, it can also be applied to other types of defects in ferrite and other materials.

It is a block diagram which shows the structure of this invention. It is a figure which shows the display screen of the measurement result of this invention. (A) It is a figure which shows the scanning image of the test body by a probe. (B) Scanned image of the specimen with the probe (in case of cracks) (A) It is a figure which shows the relationship (test body with a groove | channel) of a scanning image and a reflective source. (B) It is a figure which shows the relationship (in the case of a crack) of a scanning image and a reflective source. It is a figure which shows the propagation time of a defect front-end | tip and a defect bottom part. (A) It is a figure which shows the defect (crack) height measuring method by the intersection of a longitudinal wave and a transverse wave. (B) It is a figure which shows calculation of the intersection of a circle. It is a figure which shows the shortest propagation path of a creeping wave. It is a figure which shows propagation time of a creeping wave. It is a figure which shows propagation by a transverse wave. It is a figure which shows the propagation by a secondary creeping wave. It is a figure which shows the reflection source position of a creeping wave. It is a figure which shows calculation of the path | route of a mode conversion wave. It is a figure which shows the path | route of the mode conversion wave by the spreading of an ultrasonic wave. It is a figure which shows the case where a reflection source position is calculated | required by changing a transverse wave refraction angle. It is a figure which shows the propagation time of a mode conversion wave. It is a figure which shows propagation by a transverse wave. It is a figure which shows the propagation distance by a longitudinal wave. It is a figure which shows the path | route of a mode conversion wave. It is a figure which shows the reflection source position of a mode conversion wave. Mode conversion wave path (inclined defect) (a) Defect inclined by α degrees, (b) Defect inclined by α degrees. It is a figure which shows the reflection source position of a mode conversion wave. It is a figure which shows the calculation (tilted defect) of the path | route of a mode conversion wave. It is a figure which shows the propagation time of a longitudinal wave front-end | tip reflected wave. It is a figure which shows the longitudinal wave intersection method by a creeping wave probe. It is a figure which shows the appearance position flow figure of the locus | trajectory on a B scope. It is a figure which shows the image of the defect by a creeping wave probe. It is a figure which shows imaging of a defect It is a top view which shows other embodiment of a probe and a position detector. It is a side view of FIG. FIG. 30 is a side view in the other direction of FIG. 29. It is a figure which shows the application to a surface and an internal defect. It is a longitudinal cross-sectional view which shows other embodiment of a probe.

Explanation of symbols

10: probe, 11: transducer, 11 ′: transducer array, 11a, 11b, 11c...: Transducer unit, 20: position detector, 30, transmitter / receiver, 31: CPU, 32: transmitter, 33 : Receiving unit, 34: position detecting unit, 35: display unit, 36 signal processing unit, 40: ultrasonic flaw detector, 41: casing, 42: alignment mechanism, 43: gear, 44: arm, 44a: ball, 45a : X direction roller, 45b: y direction roller, 46a: x direction encoder, 46b: y direction encoder, 47: roller holder, 47a: receiving shaft, 48: probe holder, 48a: base, 48c: Swing part, 48b: hinge, 48d: shaft, 48e: holding part, 100: specimen, L: longitudinal wave, S: transverse wave, D: defect, M: mode conversion wave, C: creeping wave

Claims (13)

The transducer on which the longitudinal wave oblique angle probe operates is moved along the surface of the specimen in the direction of the plane to which the transmission wave belongs, and images of longitudinal waves, transverse waves, mode conversion waves, and creeping waves are displayed as trajectories. In this way, the B scope image of the received signal is displayed on the coordinates with the probe position and the reception time or a unit corresponding to this as the axis (hereinafter, “reception time etc.”) as an axis, and the wave is determined from the relative positional relationship of each trajectory. An ultrasonic test method that identifies a reflection path and a reflection source according to the type of the object and estimates the position and size of the defect. 2. The defect is characterized in that the defect communicates with the bottom of the specimen, and the size of the defect is determined based on the appearance of a creeping wave, a mode conversion wave, and a transverse wave or a longitudinal wave from the tip of the defect. The described ultrasonic test method. The probe position and the reception time are obtained from the trajectory of the transverse wave and the longitudinal wave generated from the same defect portion, respectively, and the coordinates of the same defect portion are obtained from the relationship between the two sets of probe positions and the reception time. The ultrasonic test method according to claim 1 or 2. 2. The defect communicates with a bottom of a specimen, and the probe position and reception time are obtained from a creeping wave trajectory, and the position of the defect portion on the bottom is obtained. Or the ultrasonic test method of 2. Among the defects, the probe position and the reception time are obtained from a plurality of points of the trajectory of the mode-converted wave generated from the intermediate part, respectively, and the intermediate defect is obtained from the geometric relationship such as the plurality of sets of probe positions and the reception times. The ultrasonic test method according to claim 1, wherein the coordinates of the part are obtained. The probe position and reception time are obtained from at least two points on the trajectory of the longitudinal wave generated from the same defect portion, and the coordinates of the same defect portion are determined from the relationship between these two or more sets of probe positions and reception times. The ultrasonic test method according to claim 1, wherein the ultrasonic test method is obtained. 3. The ultrasonic testing method according to claim 1, wherein the defect is imaged by displaying the coordinates of the defect portion obtained by each of the methods in two-dimensional coordinates. The ultrasonic test according to claim 1 or 2, wherein the operating transducer is moved along the surface of the specimen in the direction of the plane to which the transmission wave belongs by moving the longitudinal wave oblique angle probe. Method. The vibrator is composed of a plurality of columnar vibrators, and the actuating vibrator is switched and operated in the columnar vibrator to move the actuating vibrator along the surface of the specimen in the direction of the plane to which the transmission wave belongs. The ultrasonic test method according to claim 1, wherein the ultrasonic test method is moved. An ultrasonic test apparatus for use in the ultrasonic test method according to any one of claims 1 to 9, wherein a longitudinal wave oblique angle probe and the surface of the test specimen in the direction of a plane to which a transmission wave belongs When the probe is moved along the surface of the test object in the direction of the plane to which the transmission wave belongs, the longitudinal wave, the transverse wave, the mode conversion wave, and the clock are recorded. A display device that displays a B-scope image of a received signal at coordinates with a probe position and a reception time or a unit corresponding thereto (hereinafter referred to as “reception time, etc.”) as axes so that an image by a leaping wave is displayed; An ultrasonic testing apparatus comprising: It is an ultrasonic test apparatus used for the ultrasonic test method in any one of Claims 1-9, Comprising: The rolling mechanism which rolls on the surface of a test body, and the rotating shaft which rolls along a test body surface are mutually orthogonally crossed. An ultrasonic testing apparatus comprising a pair of rollers and an encoder that cooperates with each of the rollers, and a groove is formed on the surface of each roller in a direction along a rolling axis of each roller. 12. The rolling mechanism includes an arm that is swingably attached to the casing in pairs of front and rear and a ball at the tip thereof, and includes an alignment mechanism that synchronizes the inclination of the pair of arms 44. The ultrasonic test apparatus described in 1. The ultrasonic test apparatus used in the ultrasonic test method according to claim 1, wherein a relative positional relationship between the trajectories is specified by designating a trajectory of a B scope image with a cursor. Ultrasonic testing device characterized by

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