JPS61296266A - Ultrasonic flaw detection apparatus - Google Patents

Abstract

PURPOSE:To enable the flaw detection of a material to be inspected with good accuracy, by transmitting the ultrasonic wave to the material to be inspected and receiving the ultrasonic echo from the material to be inspected. CONSTITUTION:The transmission pulse TP outputted from an ultrasonic flaw detector 10 transmits through a coaxial cable 26 to be applied to the vibrator 16 in a probe 14. The vibrator 16 transmits an ultrasonic wave S to a material 18 to be inspected by the pulse TP and reflected in the material 18 to be inspected to generate an ultrasonic echo which is, in turn, received by the vibrator 16. The vibrator 16 converts the received ultrasonic echo to an electric signal RE which is, in turn, subsequently converted to an optical signal P by an E-O (electrooptical) converter 28 to be inputted to an O-E (photoelectric) converter 32 through an optical fiber cable 30. The converter 32 converts the signal P to an electric signal which is, in turn, inputted to the flaw detector 10 to detect the flaw 20 in the material 18 to be inspected. Therefore, when the ultrasonic flaw detection of the material 18 to be inspected was performed, the superposition of the induced noise to a flaw detection signal is prevented and the flaw detection of the material 18 to be inspected can be performed even in the vicinity of the welding device or induction furnace in a manufacturing equipment line.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an ultrasonic flaw detection device, and is particularly suitable for use when performing online ultrasonic flaw detection in places where extremely loud noise is likely to occur, such as a manufacturing equipment line for ERW steel pipes.
Concerning improvements to ultrasonic flaw detection equipment.

[Conventional technology]

A common method of ultrasonic flaw detection is the pulse reflection method, which detects flaws by transmitting ultrasonic pulses. The ultrasonic detector ($!) device using the pulse reflection method is equipped with an ultrasonic flaw detector 10 and a probe 14, as shown in FIG. 5, for example. In the figure, the output from the ultrasonic flaw detector 10 The transmitted electric signal TE (incident pulse) passes through the probe cable 12,
It is added to the vibrator 16 in the probe 14, where it is converted into mechanical vibration and generates an ultrasonic wave S. The ultrasonic wave S is transmitted to the probe 1
4 and the specimen 18, the defects 20 and the bottom surface 22 in the specimen 18 propagate in a beam shape through the specimen 18.
The ultrasonic waves are reflected at discontinuous parts such as the defect reflected wave F, the bottom surface reflected wave B, etc., and return to the transducer 16 again. The ultrasonic echoes returned to the vibrator 16, that is, the defect reflected wave F, the bottom surface reflected wave B, etc., are converted by the vibrator 16 into a received electric signal RE. The electric signal RE is input to the flaw detector 1o via the probe cable 12, amplified, and then displayed on a CRT 24 or the like that is an image display device installed in the ultrasonic flaw detector 1o. . The CRT24
represents the time for the ultrasonic wave S to propagate through the test material 18 on the horizontal axis, and the waveform on the horizontal axis of the ultrasonic echoes such as the defect reflected wave F1 and the bottom anti-Oj wave B displayed on the CRT 24 screen. The distance to the reflection source such as the defect 20 or the bottom surface 22 is displayed as the position, and the height of the ultrasonic echo is plotted on the vertical axis. Displays the strength of the echo. Furthermore, in addition to displaying on the CRT 24 as described above, it is also possible to output to a recorder, perform gate processing on the received ultrasound echoes within a certain range, and set the echo height of the ultrasound echoes that entered the gate to a threshold level. In some cases, processing such as determining the presence or absence of the defect 20 may be performed.

Problem 1 to be Solved by the Invention By the way, the conventional probe cable 12 is described in 2 in the specification of the pulse type ultrasonic flaw detection device proposed R in Japanese Patent Application Laid-Open No. 48-30985. As such, coaxial cables are usually used to improve their noise resistance. However, for example, when detecting defects in a weld immediately after electric welding, or performing flaw detection immediately before or after induction heating, the induction noise generated by the electric welding or induction heating is difficult to detect. Since the noise propagates like a mesh, an extremely large amount of induced noise is superimposed on the probe cable 12. Since the induced noise may have an echo height higher than the defect reflected wave F, flaw detection of the test material 18 may become impossible. Therefore, various noise countermeasures are generally implemented, such as double shielding of cables and noise countermeasures at the noise source, but it is impossible to completely eliminate the extremely large induced noise as described above. Sufficient S-
It was not possible to obtain the N ratio. On the other hand, in addition to implementing noise countermeasures as described above, for example,
By using the pulse type ultrasonic flaw detection device proposed in the above-mentioned Japanese Patent Application Laid-Open No. 48-30985, the threshold value of the autocorrelation type noise removal circuit is adjusted, and the waveform of the detection signal with external noise removed is A.
A method of displaying on a scope or a method of shaping a signal waveform in a flaw detection gate using a noise removal circuit of an ultrasonic flaw detection device proposed in JP-A-52-143880, and detecting a defect signal from the width of the signal waveform. Also, the above-mentioned Japanese Patent Application Laid-Open No. 52-143
880 as a conventional example, in which noise is detected using an antenna and flaw detection is stopped when noise is detected, or similarly, noise can be detected by counting defects t< )L/U. Measures are being taken. However, all of these methods are methods for distinguishing noise that enters the probe as a defect, and they have the problem that they cannot prevent induced noise from entering the cable in a superimposed manner. was. [Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and even in places where extremely large induction noise occurs, such as near a welding machine on a production line or an induction furnace, It is an object of the present invention to provide an ultrasonic flaw detection device that can perform ultrasonic flaw detection on a material to be tested with an accuracy of 11 degrees. [Means for Solving the Problems] The present invention provides an ultrasonic flaw detection apparatus, as shown in FIG. an ultrasonic wave transmitting means for transmitting ultrasonic waves to a test material using the pulse signal transmitted by the pulse signal transmission means; and an ultrasonic wave transmitter for receiving ultrasonic echoes reflected by the test material. a receiving means, an ultrasonic-optical signal converting means for converting the ultrasonic waves received by the ultrasonic receiving means into an optical signal, and transmitting the optical signal converted by the ultrasonic-optical signal converting means. and an optical-electrical information conversion means that converts the optical signal transmitted by the optical signal transmission means into an electrical signal,
The above object is achieved by detecting defects in the material to be inspected from the electrical signal converted by the optical-electrical information converting means. Further, in an embodiment of the present invention, the pulse signal outputted by the pulse signal output means is a high-voltage high-frequency signal, and the pulse signal transmission means is a high-frequency cable that can withstand high voltage, so that the pulse signal can be reliably produced with a relatively simple configuration. It is designed to generate ultrasonic waves. Furthermore, other fruits of the present invention! In an embodiment, the pulse signal transmission means includes a 151 electric-to-optical signal converter that converts the pulse signal output from the pulse signal output means into an optical signal, an optical fiber cable that transmits the optical signal, and the optical fiber. The ultrasonic transmitting means is used as a sub-optical-to-electrical signal converter that converts an optical signal transmitted through a cable into an electric signal for causing the ultrasonic transmitting means to transmit an IE sound wave. The ultrasonic wave is generated by modulating the pulse signal with the electric signal, so that the S-N ratio when transmitting the pulse signal is extremely high. Further, in a further embodiment of the present invention, the ultrasonic receiving means comprises:
The ultrasonic echoes received with a simple configuration include the ultrasonic-optical signal converting means as a vibrator that vibrates due to the received ultrasonic echoes, and a photoelastic element having a photoelastic effect attached to the one oscillator. This converts the signal into an optical signal. Furthermore, in another embodiment of the present invention, the optical fiber cable and the optical signal transmission means are a single optical fiber cable that transmits optical signals in both directions, thereby simplifying the signal transmission path and making it economical. It has improved characteristics.

[Effect]

In the present invention, when performing ultrasonic flaw detection, the pulse signal transmission means transmits the pulse signal output from the pulse signal output means for generating ultrasonic waves, and the ultrasonic transmission means uses the pulse signal to Send ultrasonic waves to
The optical signal converting means converts the ultrasonic echo reflected by the test material and received by the ultrasonic receiving means into an optical signal, and the optical-electrical information converting means converts the ultrasonic echo reflected by the test material into an optical signal, and the optical-electrical information converting means converts the ultrasonic echo reflected by the test material into an optical signal. By converting the signal into an electric signal, defects in the material to be inspected are detected. Therefore, when performing ultrasonic flaw detection on the test material, it is possible to completely prevent induced noise from being added to the flaw detection signal.
It is possible to make the ratio extremely high. Therefore, even in a place where extremely large induction noise occurs, for example, near a welding machine or an induction furnace in a manufacturing equipment line, it is possible to detect defects in the test material with high accuracy.

【Example】

Regarding the embodiment of the ultrasonic flaw detection device to which the present invention is applied,
This will be explained in detail below. First, a first example will be described. In this first embodiment, as shown in FIG. 2, an ultrasonic flaw detector 1
This is an ultrasonic flaw detection device with a probe 14 and a probe 14 mounted on the axis. Input the obtained ultrasonic echo signal and
The defect 20 inside the test material 18 is detected. The coaxial cable 26 is a high-frequency cable for high voltage and high frequency, and is used to input the transmission pulse TP to the transducer 16 in the probe 14. Inside the probe 14, a vibrator 16 and an electro-optical converter 28 (hereinafter abbreviated as E-0 converter) are arranged. That is, the vibrator 16 vibrates due to the application of the transmission pulse TP and transmits the ultrasonic wave S toward the specimen 18,
Further, the ultrasonic wave S receives a reflected echo reflected by the test material 18, and further converts the received reflected echo into an electrical signal RE. Further, the E-〇 converter 28 blinks a built-in light emitting element such as a light emitting diode (LED) or a photocell using the electric signal RE, and converts the electric signal RE into a light having a light intensity corresponding to the voltage thereof. It converts it into an optical signal P. Note that when the light emitting diode is used as a light emitting element, since the characteristics change significantly depending on temperature, a temperature measuring element for measuring the temperature can be attached to the surface of the light emitting diode. Further, a bias voltage is applied to the light emitting element by ms (not shown). Furthermore, the optical signal P may be a frequency modulated (FMI modulated) signal. One end of an optical fiber cable 30 for transmitting the optical signal P is connected to the E-0 converter 28. Further, an optical-to-electrical converter 32 (hereinafter abbreviated as 0-E converter) is connected to the other end of the optical fiber cable 30. The O-E converter 32 converts the input optical signal P into an electrical signal using a photodiode, a photomultiplier tube, or the like. Note that when the photodiode is used as the 0-E converter 32, it can be used with a temperature measuring element attached to its surface, similar to the light emitting diode. Since this first embodiment has the above configuration, it has the following effects. That is, the transmission pulse TP output from the ultrasonic flaw detector 10
is transmitted through the coaxial cable 26 and is imprinted on the transducer 1G within the probe 14. The transmission pulse TP is usually a DC pulse with a voltage of about 300V DC. The vibrator 16 transmits the ultrasonic wave S toward the material to be inspected 18 using the stamped transmission pulse TP. The ultrasonic waves S are reflected within the test material 18 and become ultrasonic echoes, which are received by the vibrator 16 again. The transducer 16 converts the received ultrasonic echo into an electrical signal RE.
and input it to the E-0 converter 28. Note that if the signal strength of the electric signal RE is weak,
It may be amplified by an amplifier and output. The E-0 converter 28 converts the electric signal RE into an optical signal P.
The optical signal P is input to the O-E converter 32 via the optical fiber cable 30. The 0-E converter 32 converts the optical signal P into an electrical signal and inputs it to the ultrasonic flaw detector 1o. The ultrasonic flaw detector 10 appropriately amplifies the electrical signal to detect defects 20 in the material 18 to be inspected. In this first embodiment, since the transmission pulse TP that generates the ultrasonic wave S in the probe 14 is a DC pulse with a voltage of about 300 V DC, the transducer 16 can be directly driven, and the configuration is relatively simple and reliable. Ultrasonic waves can be transmitted to Next, a second example will be described. As shown in FIG. 3, in this second embodiment, in place of the E-0 converter 28, optical fiber cable 30, and 0-E converter 32 in the ultrasonic flaw detection apparatus shown in the first embodiment,
An optical fiber loop is provided to convert ultrasonic echoes into optical signals and transmit them. That is, the optical fiber loop is a photoelastic element 3 attached to the vibrator 16 in the probe 14, as shown in FIG.
4 and a photoelastic element 34 disposed within the ultrasonic detector 10
It is constructed of a reference light source that irradiates light to the light source, and an optical fiber cable 30 that connects the photoelastic element 34 and the reference light source. Note that the other configurations are the same as those in the first embodiment, so explanations will be omitted. In this second embodiment, since the above-mentioned structural acid is used, it has the following effects. When transmitting the ultrasonic wave S toward the test material 18, the transmission pulse TP is transmitted to the ultrasonic flaw detector 10 as in the first embodiment.
The transmission pulse TP is output from the coaxial cable 2.
6 and is applied to the vibrator 16. The 1i mover 16 transmits an ultrasonic wave S into the test material 18 using the applied transmission pulse TP, and receives an ultrasonic echo reflected from the test material 18. Since the ultrasonic echo vibrates the vibrator 16, the photoelastic element 34 attached thereon also vibrates at the same time. Since the photoelastic element 34 is irradiated with reference light from a reference light source, it generates an optical signal P corresponding to the ultrasonic echo. The optical signal P
is transmitted through the optical fiber cable 3O and the 〇-E converter 3
2 is input. The 0-Ef converter 32 converts the optical signal P
is converted into an electrical signal and input to the ultrasonic flaw detector 10. In this second embodiment, since the probe 14 is composed of the vibrator 16 and the photoelastic element 34, the probe 14 can be configured as a cylinder, and the E-0 converter 28 It also becomes unnecessary to supply power to the Next, a third embodiment will be described. This third demonstration example, as shown in Figure 4,
Unlike the embodiment, the transmission pulse TP is transmitted as an optical signal P1. In Figure 4 °, the transmitted pulse T
The ultrasonic flaw detector 10 that detects a defect 20 in the object 18 by transmitting pulses P includes a power cable 36 that supplies power to the probe 14, and a sub-E that converts the transmitted pulse TP into an optical signal P1. A -0 converter 28A and an O-E converter 32 that converts the optical signal P returned from the probe 14 into an electrical signal are provided. One end of an optical fiber cable 30A that bidirectionally transmits the optical signals P and P1 is connected to the auxiliary E-0 converter 28A and the 0-E converter 32. Further, a sub O-E converter 32A disposed within the probe 14 and an E-0 converter 28 are connected to one end of the optical fiber cable 30A. This sub 0-E converter 32A converts the optical signal P1 into an electrical signal E1, and inputs the electrical signal E1 to the trigger pulse generator 38. The trigger pulse generator 3
8 modulates the Ti source supplied by the power cable 3G with the electric signal E1 to generate a flaw detection pulse E2, which is input to the vibrator 16. The (day shift worker 16) generates an ultrasonic wave S using the flaw detection pulse E2, transmits it into the test material 18, receives the ultrasonic echo reflected from the test material 18, and generates an electrical signal E3. Convert to preamplifier 4
0. The preamplifier 40 amplifies the electrical signal E3 and converts it into E3A to be input to the E-0 converter 28, and is provided as necessary when the electrical signal E3 is weak. The E-0 converter 2a converts the electrical signal E3A into an optical signal P, and inputs the optical signal P to the 0-E converter 32 via the optical fiber cable 30A. ○-E
The converter 32 converts the input optical signal P@electric signal and inputs it to the ultrasonic flaw detector 10. Since this third embodiment has the above configuration, it has the following effects. That is, the transmission pulse TP output from the ultrasonic flaw detector 10
is converted into an optical signal P1 by the sub E-〇 converter 28A, and is inputted to the sub-〇-E converter 32A via the bidirectional optical fiber cable 30A. The sub 0-E converter 32A converts the optical signal P1 into an electrical signal E1, which is input to the pulse generator 38. At that time, the bird is connected to the pulse generator 3 via the power cable 36.
8 and the electric signal E1,
The trigger pulse generator 38 outputs a flaw detection pulse E2. The flaw detection pulse E2 is input to the vibrator 16 and causes the vibrator 16 to generate an ultrasonic wave S. The ultrasonic wave S is transmitted into the test material 18 and reflected within the test material 18 to become an ultrasonic echo, which is received by the transducer 16. The transducer 16 converts the ultrasonic echo into an electrical signal E3,
input to preamplifier 40. The preamplifier 40 amplifies the electric signal @E3 and inputs it to the E-0 converter 28 as an electric signal E3A. The E-0 converter 28 converts the input electrical signal E3A into an optical signal P, and inputs it to the O-E converter 32 via the optical fiber cable 3GA. ! The 9i0E converter 32 converts the optical signal P into an electrical signal and inputs it to the ultrasonic flaw detector 1o. The ultrasonic flaw detector 10 uses an electric signal based on the optical signal P to
Defects 20 in the test material 18 are detected and inspected. In this third embodiment, the electric signal E1 input to the trigger pulse generator 38 is converted into an electric signal E based on the transmission pulse TP output from the ultrasonic flaw detector 10.
1, the optical signal P1 to be transmitted is a saturation signal, and the threshold of the pulse generator 38 is set to the maximum value of the optical detection level of the O-E converter 32. Further, the sub-E-, which is a means for transmitting the transmission pulse TP,
0 variation [128A and l? 10-E transducer 32A and the E-0 transducer 28, which is a means for transmitting ultrasonic echoes.
By making the wavelength characteristics different from those of the fWI O-E converter 32A, the optical signal P goes around to the pulse generator 38 via the fWI O-E converter 32A, and erroneously generates the flaw detection pulse E2. This prevents this from happening. In this third embodiment, since the transmission pulse TP is converted into an optical signal P1 and transmitted through the optical fiber cable 3o, the coaxial cable 26 is used as in the first and second embodiments.
When directly transmitting the transmission pulse TP to the transducer 16, induced noise is superimposed on the coaxial cable 26A, and the induced noise is superimposed on the transmission pulse TP! It is possible to completely prevent a single tatami mat from having a negative impact on the flaw detection results. Furthermore, since the optical fiber cable 30A is bidirectional, the optical signal transmission path can be simplified. [Effect of the invention 1] As stated above, according to the present invention, it is possible to completely prevent induced noise from being superimposed on the flaw detection signal when the material to be inspected is subjected to deep ultrasonic waves, so the S-N ratio can be extremely improved. It is possible to make it higher. Therefore, even in locations where extremely large induced noise occurs, such as near welding equipment or induction furnaces on manufacturing equipment lines, it is possible to detect defects on the test material with high accuracy. have

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the gist of the present invention, and FIGS.
FIG. 5 is a cross-sectional view including a partial block diagram showing the configuration of the third embodiment. FIG. 5 is a perspective view including a partial block diagram showing the configuration of a conventional ultrasonic flaw detection apparatus. 10... Ultrasonic flaw detector, 14... Probe, 16
... Vibrator, 18... Test material, 20...
・Defect, 26... Coaxial cable, 28.
28A...E-〇 converter, 30.30A...Optical fiber cable, 32.32A
...O-E converter, TP...transmission pulse, P, Pl...optical signal.

Claims (5)

[Claims] (1) Pulse signal output means for outputting a pulse signal for generating ultrasonic waves; pulse signal transmission means for transmitting the pulse signal; An ultrasonic transmitting means for transmitting ultrasonic waves; an ultrasonic receiving means for receiving ultrasonic echoes reflected by a test material; and an ultrasonic wave converter for converting the ultrasonic echoes received by the ultrasonic receiving means into optical signals. - an optical signal conversion means, an optical signal transmission means for transmitting the optical signal converted by the ultrasonic-optical signal conversion means, and an optical-electrical signal for converting the optical signal transmitted by the optical signal transmission means into an electrical signal. 1. An ultrasonic flaw detection apparatus comprising: a signal converting means, and detecting defects in the test material from an electrical signal converted by the optical-electrical information converting means. (2) The ultrasonic flaw detection according to claim 1, wherein the pulse signal outputted by the pulse signal output means is a high-voltage high-frequency signal, and the pulse signal transmission means is a high-frequency cable that can withstand high voltage. Device. (3) The pulse signal transmission means includes a sub-electrical-optical signal converter that converts the pulse signal output from the pulse signal output means into an optical signal, an optical fiber cable that transmits the optical signal, and an optical fiber. A sub-optical-to-electrical signal converter converts an optical signal transmitted by a cable into an electrical signal for causing the ultrasonic transmitting means to transmit an ultrasonic wave, and the ultrasonic transmitting means constantly applies an electric signal. 2. The ultrasonic flaw detection apparatus according to claim 1, wherein the ultrasonic flaw detection apparatus generates ultrasonic waves by modulating voltage with the electric signal. (4) The ultrasonic receiving means is a transducer that vibrates due to received ultrasonic echoes, and the ultrasonic-optical signal converting means is a photoelastic element attached to the transducer and having a photoelastic effect. An ultrasonic flaw detection device according to claim 1. (5) The ultrasonic flaw detection apparatus according to claim 3, wherein the optical fiber cable and the optical signal transmission means are a single optical fiber cable that transmits optical signals in both directions.