JPS63103963A - Ultrasonic flaw detector - Google Patents

Abstract

PURPOSE:To performs flaw detection over the entire area of a weld zone by measuring the beam path length of an ultrasonic wave signal from the movement distance of a probe and delaying a gate start signal by the beam path length. CONSTITUTION:An ultrasonic wave 13 is inputted from the probe 13 to a test body 1 with a signal from a transmitting and receiving circuit 20 and echo from a defect is received to perform flaw detection. At this time, an internal surface defect 15 or external surface defect 14 is detected by moving the probe 3 from left to right by moving devices 5-8. Then the movement distance of the probe is measured and the beam path length is measured by a beam path length measuring circuit 26. Then, a gate start signal (GS) setting circuit 23 delays a GS44 according to the beam path length and a gate (GL) setting circuit 24 for defect detection generate a GL42. Then, the height of an echo from the transmitting and receiving circuit 20 is decided 30 by using the width of the GL42. Therefore, the GS is delayed by the beam path length, so the GL is set at a flaw detection position all the time and defects in the entire area of internal - external positions are detected without resetting the position of the GL.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is an ultrasonic flaw detection device for obliquely detecting welds of steel pipes or steel plates. ) This relates to an ultrasonic flaw detection device that attempts to track f.

[Prior art] ゛Conventional ultrasonic flaw detection equipment for detecting flaws in welded parts of steel pipes or steel plates is described in 1, for example, Inspection News December 1958 issue F.
The test shown in No. 12 is used to detect flaws in the welded parts of piping for Ashi reactor cooling water.

Figure 5 is a diagram of a conventional ultrasonic detective device for flaw detection, for example, in steel pipes. In Figure 9, (1) is the test specimen, (2) is the radiation fin that dissipates the heat of the fluid inside the pipe, and (3) is the probe. .

! 1 (1 is the cable that transmits the transmitted pulse and the received signal received by the probe, αυ is the couplant between the probe and the test body, 1IX5 is the piping weld, and α3 is the cable that connects the probe to the test body) The incident ultrasonic wave, Q41 is a defect on the outer surface side of the bath contact part (hereinafter referred to as an outer surface defect), (151 is a defect on the inner surface side of the II8 contact part (hereinafter referred to as an inner surface defect), αn is a welded part of the heat dissipation fin, (2) is a transmitting/receiving circuit that sends a transmission signal to the probe through the cable and receives an electric signal from the probe; can is a defect detection gate (hereinafter referred to as G);
A GS setting circuit generates a gate start signal (hereinafter referred to as GS) that determines the rising edge of the GS signal (hereinafter referred to as GS); C3 is a reference clock generation circuit that sends a synchronization signal to the transmitting/receiving circuit (2) and the GS setting circuit (211); A GL setting circuit that generates a falling GL; 1 is a threshold setting circuit that sets a p threshold to determine the height of a defective echo; C31 extracts an echo within the HGL and sets its height as a threshold; A determination circuit that makes a determination based on a value, and C111 is a display/recording circuit that displays and records the determination result of the determination circuit (to).

FIG. 1 is a diagram showing echoes and gates when a welded portion of a pipe is flaw-detected at the position shown in FIG. 5 using a conventional apparatus. (14 is the echo of the external defect shown in FIG. 4, 01 is the transmission pulse sent from the reference clock generation circuit A to the transmitter/receiver circuit
as, which is sent to the L setting circuit Q, O (4X5 is the GL
GL, which is generated in the setting circuit U41 and sent to the 1 determination circuit (to), is a transmission echo.

FIG. 6 is a diagram showing flaw detection of a pipe welded part using a conventional device, in which the probe is brought close to the welded part so that the ultrasonic waves hit the inner surface of the welded part. In the figure, from (1) to (Iη) is W, which is the same as in Figure 5.

Figure 8 is a diagram showing the echoes and gates when a welded part of a pipe is detected using a conventional device at the position shown in Figure 6. It is the same as the figure. (15 is an echo of the inner surface defect.

(No. 17 is an echo of the heat dissipation fin weld.

FIG. 9 shows the conventional device in the position shown in FIG. 6.

<15 in the figure when the width of GL is narrowed and the welded part is detected.
a) e ("S, 14IN to @ and the area are the same as in Figure 8.

FIG. 10 shows the conventional device in the position shown in FIG.
This is a diagram when the welded part is detected by narrowing the width (15th,
(41 to @ and (a) are the same as in FIG. 7.

A conventional ultrasonic flaw detection device is configured as described above.

Transmission pulse C4 output by the reference clock generation circuit
At the rising edge of 0, a transmission signal is sent to the transducer (3) via the cable wire to the transducer (3), and the transducer (3)
The ultrasonic wave o3 from
). The incident ultrasonic wave is reflected by the outer surface defect α aneurysm and is received by the transmitter/receiver circuit ■ as an outer surface defect echo (14) shown in FIG. , GI3 setting circuit Q11
and ()L setting circuit c4 is set in advance at the position shown in FIG. It is determined by the set threshold UK determination circuit (to) and is displayed and recorded in the display recording circuit C (+1).

Next, in order to detect the inner ml defect α51 in the welded part.

It is necessary to move the probe (3) to the position shown in FIG.

In this case, the ultrasonic wave is reflected by the inner surface defect ttS and received as an inner surface defect echo (+58) shown in FIG.

This echo appears in GLf43, so its coco-
The height is determined and displayed and recorded. In this way welding part Q2
In order to detect the entire weld depth, scanning is performed between the probe position shown in FIG. 5 and the probe position shown in FIG.

[Problem that the invention seeks to solve]

When the probe (3) is in the position shown in Figure 6, G in Figure 8
Inside L43, there is an external defect echo (14
An echo of the radiation fin weld (1
7ri appears. Naturally, since this echo is also within GLη2, its echo tube is determined and recorded and displayed.

However, this radiation fin welded area echo (17) is not a reflected echo from the part that should be detected with the conventional device, but it is incorrectly displayed and recorded as if there was a defect in welded area +12.This radiation fin welded area echo (In order to remove 17 from GL (43, l/(,
If the width of GLf43 is shortened, the echo will not enter the GL(43) and will not be displayed and recorded incorrectly.

However, when the probe (3) was in the position shown in Figure 5,
As shown in FIG. 10, since GL(6) is short, the external defect echo (14) does not fall within GL(43), resulting in the problem of overlooking harmful defects.

This invention was made to solve this problem, and the GL is set only in the flaw detection range of the weld 1z, so that even if the probe moves to detect the entire depth of the weld, the weld will always be detected. The purpose of the present invention is to provide an ultrasonic flaw detection device in which a gate is set only for

[Means for solving problems]

The ultrasonic flaw detection device according to the present invention includes a position counting circuit that measures the moving distance of the probe, a beam path measuring circuit that calculates the ultrasonic beam path from the distance, and a G8 delay that delays GElf: from the beam path. This circuit is configured to cause the rise of fi and GL to follow the rise of the GEi delay circuit.

[Effect]

In this invention, the moving distance M of the probe is measured and the beam path corresponding to this is determined. GL in this beam path
GL is always set at the welding part regardless of the position of the probe.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

(1) is the test object, (2) is the radiation fin, (3) is the probe, a holder that holds the +41f'i probe, and (5) is the holder that is attached to the holder and moves the probe. 18) is a rotary encoder that outputs pulses that serve as the probe movement clock; ) is the holder M that holds the above probe, rank, pinion, and rotary encoder and fixes it to the test specimen, Ql is the cable connecting the transceiver circuit and the probe, the cable connecting the position counting circuit and the rotary encoder, and The couplant between the probe and the specimen, r12 is the butt weld of the specimen, (1
3 is the ultrasonic wave incident on the inside of the test specimen (1) through the probe (3), and a41 is the outer surface defect in the welded part.

Uri is an internal defect in the welded part (Iη is the heat dissipation fin welded part, c!1 is the probe (3) that sends a transmission signal to the probe (3)
3) A transmitting/receiving circuit that receives all the echoes received and converted into electrical signals, a 38 setting circuit for determining the rising edge of 211t'iGL, the above-mentioned transmitting/receiving circuit, and G.
88 A reference clock generation circuit that sends a reference clock to the setting path, (C) is a position count circuit that counts the distance clock from the rotary encoder τ8), @ is a zero set that makes the output of the position count circuit (C) zero. switch, (a) is a beam path measuring circuit that measures the beam path corresponding to the distance counted by the position counting circuit C1, and (to) is a beam path measuring circuit according to the refraction angle of the probe used. (to) is a volume that adjusts the value of mlnθ used in (to). delay circuit,
1j41 is the GL whose falling edge of the delay G5l4) delayed by the GEI delay circuit (c) generates GL@3 from 9.
A setting circuit (to) is a threshold setting circuit for setting a threshold value for determining the height of an echo, (nf; jGL@3
A determination circuit that determines the height of an echo in the above threshold value, and on is a display/recording circuit that displays and records the result determined by the determination circuit.

FIG. 2 is a diagram showing reception echoes and gates of the device according to the present invention. In FIG. 1, # (tSa> is an internal defect echo, and (17) is an echo at the heat dissipation fin junction.

(41 is the transmission pulse, L4+) is G8. (4: I is the beam path that is the output of the beam path measuring circuit, 04 is the GI9
The delay Gs, which is the output of the delay circuit, G13 is GL, and ω is the transmitted echo. Figure 3 shows the result when the probe (3) is moved from the position shown in Figure 1 to the position where an external defect is detected. In the figure (1
) to u9 are the same as in FIG. (49 is the moving distance of the probe, (43 is the beam path corresponding to this distance,
+419 is the refraction angle θ.

FIG. 4 is a diagram showing received echoes and gates at the positions shown in FIG. 3, (4G to 94. (A) are the same as in FIG. 2. (14) is an external defect echo.

In the ultrasonic flaw detection apparatus configured as described above, as shown in FIG.

A transmission signal is sent from the transmitter/receiver circuit ■ to the probe (3) via the cable a1, and the ultrasonic wave a3 from the probe (3) is incident on the inside of the test object (1) via the couplant aU. . The incident ultrasonic wave is reflected by the inner surface defect tls and is received by the transmitter/receiver circuit (15) as shown in FIG. (GSf40 that determines the rise 9 of 42
is set at the position shown in FIG.

At this position, the zero cent switch (5) is turned on to make the output of the position count circuit (c) zero. Since the position count is zero, the beam path length (43) output from the beam path measuring circuit (a) is zero.

Therefore, the delayed GS delayed by the GS delay circuit (c)
(441 is GS (same position as 40. GLρno is G
The L setting circuit generates a delay G day @falling edge of the bump, and its width is set narrow as shown in FIG.

Only 15 internal defect echoes are captured in GLf43, and the height of this echo is judged by the judgment circuit (to) based on the threshold set by the threshold setting circuit (to), and the result is is displayed and recorded in the display recording circuit ON.

In this way, the entire width of aLI4Z should be inspected for welds [1
Since it is set only to 2, the heat radiation fin bath contact echo (
17 will fall within GL (4a) and will not be recorded incorrectly.

Next, in order to detect the outer surface defect Q4, it is necessary to move the probe to the position shown in FIG. The atn setting in this case will be explained below.

The probe (3) moves Y, f4!9 as shown in FIG.

The clock corresponding to this Y is the rotary encoder 18.
) is input to the position counting circuit (c), becomes a count value for Y1, and is sent to the beam path measuring circuit. Beam path length (430f'iY, , (45) and refraction angle θ (48
It can be determined from the beam path (46s=Y/output θ). In the beam path measuring circuit (c), the output is set in advance using the output 0 adjustment volume according to the above equation.

Using the value of the output θ, the value of the beam path 8a3 shown in FIG. 4 is calculated and output to the aS delay circuit (to). The GS delay circuit (c) outputs the beam path (delay G14 delayed until the falling edge of signal 43) f: to the GL setting circuit C4. G1.
The I setting circuit c2 generates aLa2 at the falling edge of the delay G8 (44). The width of GL (C) is the same as that shown in FIG. As shown in FIG. 4, since there are 14 external defect echoes in the GL (6), the height of this echo is determined by the determination circuit ω, and the result is sent to the display/recording circuit O1.
1 is displayed and recorded.

As the probe (3) moves as described above, the change in the beam path to the bath contact part is determined from the distance count corresponding to the moving distance, and in order to follow this change KGL, GL is always set at the weld part. Ru. Therefore, unlike conventional devices, there is no need to set the GL to a wide width, or to make a judgment based on unrelated miscellaneous echoes such as echoes from the heat dissipating fin welds, thereby causing incorrect display and recording.

〔Effect of the invention〕

As explained above, this invention measures the moving distance of the probe and calculates the beam path from this distance.

By delaying G8 by this beam path length, G
L can always be set as the flaw detection area.

Also, even if you move the probe to detect the entire area from the outer surface to the inner surface of the flaw detection area, the GL is always set at the flaw detection area, so it is necessary to reset the GL position. This has the effect that there is no need to make it wider.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 3 show embodiments of the present invention. FIG. 2 and FIG. 4 are diagrams showing the transmission signal, gate, and echo of the ultrasonic flaw detection device according to the present invention, and FIG. FIG. 6 is a diagram showing a conventional ultrasonic flaw detection device, FIG. FIGS. 8, 9, and 10 are diagrams showing transmission signals, gates, and echoes of conventional devices. In the figure (ri is the test specimen, (2) is the radiation fin, (3)
is the probe, ]4) is the holder, (5) is the rank, and (7) is the binion. 18) is a rotary encoder, (9) is a holding mechanism, (
11 is the cable, (111 is the couplant, a'a is the welded part, 031 is the ultrasonic wave, G4 is the external defect, US is the internal defect, aη is the heat radiation fin welded part, ■ is the transmitting/receiving circuit, an is the GEI setting circuit, is the reference clock generation circuit, 3 is the GEI delay circuit, f
241 is a GL setting circuit, (C) is a position count circuit, (
(to) is the beam path measurement circuit, (5) is the zero cent switch, (to) is the sin θ adjustment volume, C is the threshold setting circuit, 131 is the judgment circuit, can is the display recording circuit, (
41 is a transmission pulse. (43 is the beam path, the same is the delay OB, the distance is the travel distance, (4Q is the refraction angle, and FA is the transmitted signal. In each figure, the same reference numerals indicate the same or equivalent parts. Shows. Masuo Oiwa 2nd Figure 40j 1 Praise Rus 47: G5 42: GL 43: Beam? Death! 44: y! Certification aS 50: 1818th issue! 04 Figure 42 Mfl 9th tank 10 days

Claims (1)

[Claims] A synchronization signal generation circuit that generates a synchronization signal in a device that repeatedly transmits ultrasonic pulses to a welded part of a test object and receives the ultrasonic pulses or reflected ultrasonic pulses;
A transmission circuit that transmits a transmission signal in synchronization with the synchronization signal generated from the synchronization signal generation circuit, and an oblique angle probe that converts this transmission signal into an ultrasonic signal and makes it incident from the surface of the test specimen via a couplant. a receiving circuit that converts the ultrasonic signal reflected from inside the test object into an electrical signal and receives it, a measuring circuit that measures the distance traveled by the probe, and a measuring circuit that measures the distance traveled by the measuring circuit. It is characterized by being equipped with a beam path measurement circuit that determines the beam path of the ultrasonic signal within the test object, and a gate delay circuit that moves the position of the defect detection gate according to the beam path measured by the beam path measurement circuit. Ultrasonic flaw detection equipment.