JPH054009U - Ultrasonic flaw detector - Google Patents

Abstract

(57) [Summary] [Purpose] Detect a flaw by ensuring a sufficient flaw detection range in the thickness direction of the test piece and setting the judgment value of the defect echo without erroneous judgment separately on the surface and center of the test piece. The purpose is to Furthermore, the purpose is to detect an increase in the distance between the probe and the test body based on the average value of surface echoes and issue an alarm. [Structure] A split type probe, a reference signal generation circuit, a transmission / reception circuit, a surface gate circuit, a central gate circuit,
Surface echo height measurement circuit, central echo height measurement circuit, surface echo height determination circuit, central echo height determination circuit, surface echo height averaging circuit, surface average echo height It is composed of a judgment circuit and a display circuit. [Effect] It is possible to perform flaw detection with a small flaw detection range in the plate thickness direction and without erroneous determination. It is also possible to monitor the tilt of the probe and the increase in the gap between the probe and the test body.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  This invention is an ultrasonic flaw detector for flaw detection inside a steel sheet. By providing two gates and changing the judgment value of the defect echo in each gate, It is intended to detect flaws with a small number of points and to inspect a wide range as far as the plate thickness direction. It Furthermore, the average height of the surface echo is measured to determine the mounting state of the probe and the The gap is to be monitored.

[0002]

[Prior art]

  A conventional ultrasonic flaw detector for flaw detection of a steel sheet is, for example, a non-destructive inspection VOL. 29, N O. 10 is shown in P731, and is a digital ultrasonic flaw detector for steel plates. It FIG. 4 is a diagram of, for example, an ultrasonic flaw detector for flaw detection of a conventional steel plate. 1 is a steel plate which is a test body, 2 is a roller for carrying the test body, 3 is a carrying direction, 4 is a defect inside the specimen, 5 is a split type probe, 6 is a contact medium, and 7 is from the probe 5. Ultrasonic waves, 8 is a cable for transmitting a transmission pulse and a reception echo, 10 is the above Transmits a transmission signal through the cable 8 and receives a reception echo from the probe 5. Transmitter / receiver circuit, 11 is a reference for sending a synchronization signal to the transmitter / receiver circuit 10 and the gate circuit. The signal generation circuit, 12 is a part of the necessary portion of the reception echo received by the transmission / reception circuit. A gate circuit for extracting the echo, and 13 is a defect circuit extracted by the gate circuit. An echo height measuring circuit for measuring the height of the cord, 14 is a gate signal to the gate circuit And a gate setting circuit 15 for supplying the energy, which is measured by the echo height measuring circuit. Echo height determination circuit for determining coe height, 16 is determined by the echo height determination circuit A judgment value setting circuit for supplying a value, 17 displays the judgment result of the echo height judgment circuit It is a display circuit. FIG. 5 is a diagram showing the states of the ultrasonic echo, the gate, and the defect echo. ) Is a diagram showing the relationship between the probe and the test body, 1 is the test body, 4a is a defect, 5 is a split type A probe, 6 is a contact medium, 7 is an ultrasonic wave, 8 is a cable, and FIG. In the figure showing the state, 31 is a reception echo output from the transmission / reception circuit, and 50a is The surface echo received by the receiving side of the split probe, 51a is a defect echo, and 52 is a test. The bottom echo of the test object, FIG. 5 (c) is a diagram showing the state of the gate signal, and 33 is the gate signal. Gate signal supplied from the gate setting circuit to the gate circuit. Fig. 32 is a diagram showing the state of the flow, and 32 is supplied from the gate circuit to the echo height measuring circuit. The defect echo 34a is a defect echo measured by the echo height measuring circuit. -Height, 35a is the judgment value set by the judgment value setting circuit. FIG. 6 is also a diagram showing the states of the ultrasonic echo, the gate, and the defect echo, and FIG. Is a diagram showing the relationship between the probe and the test body. 1 is the test body, 4b is a defect, 5 is a split type probe. A tentacle, 6 is a contact medium, 7 is an ultrasonic wave, 8 is a cable, and FIG. In the figure showing the child, 31 is a reception echo output from the transmission / reception circuit, and 50b is a minute. Surface echo received by the receiving side of the split probe, 51b is a defect echo, 52 is a test The bottom echo of the body, FIG. 6 (c) is a diagram showing the state of the gate signal, 33 is the gate The gate signal supplied from the gate setting circuit to the gate circuit, as shown in FIG. In the figure showing the child, 32 is a gap supplied to the echo height measuring circuit from the gate circuit. The echoes 35b are the judgment values set by the judgment value setting circuit. FIG. 7 is also a diagram showing the states of the ultrasonic echo, the gate, and the defect echo. ) Is a diagram showing the relationship between the probe and the test body, 1 is the test body, 4b is a defect, and 5 is a division. Type probe, 6 is a contact medium, 7 is an ultrasonic wave, 8 is a cable, and FIG. In the figure, the reference numeral 31 indicates a reception echo output from the transmission / reception circuit, and 50c. Is a surface echo received on the receiving side of the split probe, 52 is a bottom echo of the test object, FIG. 7 (c) is a diagram showing the state of the gate signal, and 33 is a gate signal from the gate setting circuit. The gate signal supplied to the gate circuit, FIG. 7D is a diagram showing the state of the defect echo. , 32 are defect echoes supplied to the echo height measuring circuit from the gate circuit, 34 c is the defect echo height measured by the echo height measuring circuit, and 35c is the above It is the judgment value set by the judgment value setting circuit.

[0003]   Next, the operation will be described. When detecting a steel plate having a plate thickness as shown in FIG. As shown in FIG. 5 (c), the setting of the tone is from the end of the surface echo 50a to the bottom echo. If the plate thickness is changed before 52, and the plate thickness is changed, only the trailing edge of the gate is tested. The setting is changed so that it is just before the bottom echo of the specimen, but the gate falls Is always at the end of the surface echo 50a. The reason for this is that the surface echo 50a The height may be equal to or higher than the echo height of a small defect. This is because the gate cannot be set in the portion of 50a. Usually surface echo 50a Is about 5 mm from the surface of the test body, and this portion is an undetected area. As shown in FIG. 5D, the defect echo 51a due to the defect 4a is removed by the gate. And the height 34a is measured by the echo height measuring circuit, and the echo height is measured. Is compared with the determination value 35a by the determination circuit, and as a result, the echo height is determined by the determination value 35a. Is exceeded, so it is displayed as a defect. Next, a thin steel plate as shown in FIG. When detecting flaws, the rising edge of the gate is displayed in the same way as in FIG. 5 as shown in FIG. It is from the end of the surface echo 50a, and its fall is the bottom echo 52 of the test object. Since it is just before, the gate width becomes narrower and a sufficient flaw detection range can be secured in the plate thickness direction. Absent. Therefore, as shown in FIG. 6A, the large defect 4b is the central portion of the plate thickness of the test body. , It is not taken out by the gate signal 33 even if it exists in Nothing appears in the defect echo, and since it is smaller than the judgment value, it is displayed that there is no defect. this In such a case, if the gate signal is broadly set in the plate thickness direction including the surface echo, the defect 4b Echo 51b is extracted and judged to have a defect, but it is small as shown in FIG. There is a problem when trying to detect defects. FIG. 7 shows an example of the gate position setting. The gate position set by the circuit is set to the surface echo 50c as shown in FIG. 7 (c). In the case of setting including, the test specimen has no defect, but as shown in FIG. The echo height 34c of the surface echo 50c extracted by the pulse signal 33 is determined. Since the value exceeds 35a, it is determined and displayed that there is a defect. In this way the center of the test piece Or if you want to detect a small defect on the bottom, the gate will give a surface echo. There is a problem that it cannot be set because it includes it.

[0004]

[Problems to be solved by the device]

  Since the conventional ultrasonic flaw detector is constructed as described above, The inspection range in the plate thickness direction and the judgment value of the defect echo cannot be compatible, and the flaw detection range becomes narrow. However, there is a problem of overlooking harmful defects. The complicated position of changing the rising position of the camera and the judgment value of the defect echo each time. There was a problem that a work was needed.

[0005]   This invention was made in order to solve the above-mentioned problems. A judgment value that secures a sufficient flaw detection range in the plate thickness direction regardless of the plate thickness and does not cause erroneous judgment. The purpose of the invention is to provide an ultrasonic flaw detector that can set the surface area and the center area of the test piece. And Furthermore, this invention is based on the inclination of the probe and the change in the distance between the probe and the test piece. When surface echo increases, it is detected and an alarm is issued to perform highly reliable inspection. It is an object of the present invention to provide an ultrasonic flaw detector.

[0006]

[Means for Solving the Problems]

  The ultrasonic flaw detector according to the present invention has a surface gate circuit and a central gate circuit. And surface echo height measuring circuit, central echo height measuring circuit, surface echo Height determination circuit, central echo height determination circuit, surface echo height averaging circuit, Equipped with a surface area average echo height determination circuit, each of the surface echo and the central echo Separately, the height of the surface echo and the height of the central echo are judged with different judgment values. It was done so. Also, by determining the average echo height on the surface, It is designed to detect an increase in echo.

[0007]

[Action]

  In this invention, it has two gates on the surface and the center in the plate thickness direction, and Since each judgment value can be set individually, there is little undetected area in the plate thickness direction and erroneous judgments are made. You can do flawless inspection. Also, the height of the surface echo is constantly taken out and Reliable inspection because the inclination of the probe and the distance from the test piece can be monitored by the average value. It can be performed.

[0008]

【Example】

Example 1.   An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a test body A certain steel plate, 2 rollers for conveying the above-mentioned specimen, 3 a conveying direction, 4 inside the specimen , 5 is a split type probe, 6 is a contact medium, 7 is an ultrasonic wave emitted from the probe 5, Reference numeral 8 is a cable for transmitting a transmission pulse and reception echo, and 10 is a cable through the cable 8. To transmit and receive a transmission signal, and to receive a reception echo from the split type probe 5 A circuit, 11 is a reference signal generator for sending a synchronizing signal to the transmitting and receiving circuit 10 and the gate circuit. A circuit, 60 is a surface portion in the plate thickness direction of the reception echo received by the transmission / reception circuit. Surface gate circuit for extracting echo, 61 is reception received by the transmission / reception circuit A central gate circuit for extracting an echo at the central portion in the thickness direction of the echo, 62 is the above-mentioned table A front surface gate position setting circuit for supplying a gate signal to the front surface gate circuit, 63 is A central gate position setting circuit for supplying a gate signal to the central gate circuit, 64 is a front The surface area for measuring the height of the surface echo extracted by the surface gate circuit Co-height measuring circuit, 65 is the central eco taken out by the central gate circuit A central echo height measuring circuit for measuring the height of the surface, 66 is the surface echo height measuring circuit. Echo height determination circuit for determining the echo height of the surface measured by a constant circuit , 67 indicates the central echo height measured by the central echo height measuring circuit. Central echo height determination circuit for determining, 68 is determined by the surface echo height determination circuit A surface echo height judgment value setting circuit for supplying a value, 69 is the central echo height judgment circuit Central part echo height judgment value setting circuit for supplying a judgment value to a constant circuit, 70 is the surface part The surface echo height measured by the echo height measurement circuit is added for each transmission repetition. The surface echo height averaging circuit 71 for calculating the average value after the flaw detection of the test body is completed, Determining the surface average echo height calculated by the surface echo height averaging circuit A surface average echo height determination circuit, and 72 denotes the surface average echo height determination circuit A surface average echo height judgment value setting circuit for supplying a judgment value, 17 is the surface eco -It is a height judgment circuit. FIG. 2 shows the ultrasonic sound when the test piece shown in FIG. 2 is flaw-detected by the ultrasonic flaw detector according to the present invention. Fig. 2 (a) is a diagram showing the state of wave echo, gate, and defect echo. In the figure showing the relationship between the bodies, 1 is a test body, 4b is a defect, 5 is a split probe, and 6 is a contact. A medium, 7 is an ultrasonic wave, 8 is a cable, and FIG. 2B is a diagram showing the state of a reception echo. , 31 is a reception echo output from the transmission / reception circuit, 50b is a surface echo, 51 b is the defect echo of the defect 4b, 52 is the bottom echo of the specimen, and FIG. 10 is a diagram showing the state of the gate signal, in which 40 is a surface portion from the surface gate position setting circuit. The gate signal supplied to the gate circuit, FIG. 2D shows the state of the central gate signal. In the figure, 41 is supplied to the central gate circuit from the central gate position setting circuit. 2 (e) is a diagram showing the state of the surface defect echo, and 42 is the front. The surface echo extracted by the surface gate circuit, 44b is the surface eco. -The height of the surface echo measured by the height measuring circuit, and 46 is the surface echo Judgment value set by the height judgment value setting circuit, FIG. 43 is a diagram showing the state of FIG. Reference numeral 47 is a judgment value set by the central echo height judgment value setting circuit. is there. FIG. 3 also shows an ultrasonic flaw detector according to the present invention, in which the probe shown in FIG. In the figure showing the state of ultrasonic echo, gate and defect echo when flaw detection is performed in 3 (a) is a diagram showing the relationship between the probe and the test body, 1 is the test body, 4b is a defect, 5 is Split probe, 6 is a contact medium, 7 is an ultrasonic wave, 8 is a cable, and FIG. FIG. 31 is a diagram showing the state of the co, in which 31 is a reception echo output from the transmission / reception circuit, 5 0c is the surface echo, 51a is the defect echo of the defect 4a, and 52 is the bottom echo of the specimen. 3 (c) is a diagram showing the state of the front surface gate signal, and 40 is the front surface gate signal. The gate signal supplied from the position setting circuit to the front surface gate circuit, FIG. FIG. 4 is a diagram showing a state of a partial gate signal, in which 41 is a central gate position setting circuit. Gate signal supplied to the central gate circuit, Fig. 3 (e) shows the state of surface defect echo In the figure, 42 is the surface echo extracted by the surface gate circuit, 44c is the surface echo height measured by the surface echo height measuring circuit, 46 is a judgment value set by the surface echo height judgment value setting circuit, and 49 is Surface portion average echo height determination value setting circuit set by the surface portion average echo height 3 (f) is a diagram showing a state of a central defect echo, and 43 is the above The central echo extracted by the central gate circuit, 45 is the central echo height Central echo height measured by the measuring circuit, 47 is the central echo height determination It is the judgment value set by the value setting circuit.

[0009]   Next, the operation of the ultrasonic flaw detector according to the present invention will be described. Thin shown in Figure 2 When detecting a test piece having a plate thickness, the surface gate signal 40 is as shown in FIG. 2 (c). The surface echo 50b is set from rising to falling, and the center gate As shown in Fig. 2 (d), the signal 41 changes from the trailing edge of the surface echo to the bottom edge of the specimen. It is set by the plate thickness just before the coat 52. And the echo height of each gate As shown in FIGS. 2 (e) and 2 (f), the surface judgment value is the surface echo height. The judgment value 46 is set higher than the height of a normal surface echo, and the central part is centered. In order to detect a defect in which the coating height judgment value 47 is small as in the conventional device shown in FIG. Set low. The test body 1 has a defect 4b, and the defect echo 51b is on the surface. Appears in the same position as the echo. As shown in FIG. 2 (e), The surface echo 42 taken out by the surface echo height measuring circuit 64 Height is measured. The surface echo height 44b exceeds the surface echo height judgment value 46. Therefore, it is determined by the surface echo height determination circuit that there is a defect, and the display circuit 17 Is displayed in. As shown in FIG. 2F, the central gate circuit 61 takes out The central echo 43 is measured by the central echo height measuring circuit. And compared with the center echo height variation value 47. In the center gate in the test body Since there is no echo, it is determined that there is no defect and is displayed. Thus, in the conventional device, Since the gate is set on the surface where the gate could not be set, defects on the surface are detected. Can be issued. There was a small defect in the center of the test piece as shown in Fig. 4 (a). In the case of Since they are compared, they can be detected. Next, another operation of the ultrasonic flaw detector according to the present invention will be described. Shown in Figure 3 In the case where a probe with a small defect 4a is detected with the probe tilted, the test piece shown in FIG. ), The received echo 31 has a height higher than usual because the probe is tilted. Large surface echo 50c, defect echo 51a of defect 4a, and bottom echo 5 of the test object There are two. As shown in FIG. 3C, the front surface gate signal 40 has a rising edge of the front surface echo. It is set from the slope to the fall, and the central gate is a surface eco as shown in Fig. 3 (d). It is set from the trailing edge to just before the bottom echo. The defect echo of defect 4a is The center echo circuit 65 is taken out by the central gate circuit 61 of FIG. The echo height 45 of FIG. 2 (f) is measured by the Is compared with the center echo height judgment value 47, and there is a defect because it exceeds the judgment value. Is displayed. For the front surface, the front surface taken out by the front gate circuit The echo 42 is the surface echo height determination circuit 66, and its height 44c in FIG. Is compared with the surface echo height judgment value 47. In this case, the judgment value is 46 on the surface. Since there are no defects that exceed, it is determined that there is no defect and is displayed. At the same time surface echo height The length 44c is added by the surface echo height averaging circuit 70 of FIG. The test specimens are averaged after the flaw detection. The surface average echo height determination circuit 7 At 1, the value is compared with a surface average echo height determination value 49. In the case of FIG. 3, a split type probe No. 5 shows flaw detection in a tilted state, so the average value of the surface echo is also as shown in Fig. 3 (e). Since it becomes a value of 44c and exceeds the surface average echo height judgment value 49, a probe is attached. Displayed as bad. Figure 3 shows the case where the probe is tilted. Even if the distance becomes large, the echo on the surface also increases and the probe is not attached properly. Is displayed as. Normally, a split-type transducer is used to detect steel plates by the gap method. The gap between the tentacle and the test piece is about 0.5 mm, and every time this value increases by 0.1 mm It is known that the surface echo received by the transducer on the receiving side of the probe increases by about 2 dB. Has been. In this example, there is no defect on the surface portion, but the surface echo judgment value 46 is exceeded. If there is a defect echo, the defect is displayed at the same time.

[Effect of device]

  As explained above, this device has gates on the surface and the center of the test piece. And since each echo height judgment value can be set, there is little flaw detection range in the plate thickness direction, The central part has a lower judgment value and is rigorously inspected. There is an effect that such a highly reliable inspection can be performed. At the same time, the surface echo The height is measured during flaw detection and the average value after flaw detection is used to determine how the probe is attached and between the probe and the test piece. The distance is monitored and an alarm is displayed if the probe is tilted or the gap between the probe and the test specimen is large. The effect is that quick repairs and adjustments can be made.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an ultrasonic flaw detector according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between an ultrasonic echo, a gate, and a defect echo of an ultrasonic flaw detector according to an embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between an ultrasonic echo, a gate, and a defect echo of the ultrasonic flaw detector according to the embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a conventional ultrasonic flaw detector.

FIG. 5 is a diagram showing a relationship between an ultrasonic echo of a conventional ultrasonic flaw detector and a gate and a defect echo.

FIG. 6 is a diagram showing a relationship between an ultrasonic echo, a gate, and a defect echo of a conventional ultrasonic flaw detector.

FIG. 7 is a diagram showing a relationship between an ultrasonic echo of a conventional ultrasonic flaw detector and a gate and a defect echo.

[Explanation of symbols]

5 split type probe 10 Transmitter / receiver circuit 11 Reference signal generation circuit 60 Front gate circuit 61 Central gate circuit 62 Front gate position setting circuit 63 Central gate position setting circuit 64 Surface echo height measurement circuit 65 Central echo height measurement circuit 66 Surface echo height determination circuit 67 Central echo height judgment circuit 68 Surface echo height judgment value setting circuit 69 Central echo height judgment value setting circuit 70 Surface echo height averaging circuit 71 Surface average echo height judgment circuit 72 Surface average echo height judgment value setting circuit 17 Display circuit

Claims (2)

[Scope of utility model registration request] 1. A reference signal for generating a synchronizing signal in a device for repeatedly transmitting ultrasonic waves from the outer surface to the inside of a steel plate as a test body and receiving the ultrasonic signal reflected from a defect inside the test body. A generation circuit, a transmission / reception circuit that transmits in synchronization with a synchronization signal generated from the circuit, and receives an electric signal (reception signal) converted from an ultrasonic wave by a split probe, and a reception echo on a time axis. A surface part gate circuit that gates the surface part of the test body to take out an echo in the gate, a surface part gate position setting circuit that supplies a gate signal to the gate circuit, and a central part of the test body on the time axis of the received echo A central gate circuit for gated to extract echoes in the gate; a central gate position setting circuit for supplying a gate signal to the gate circuit; Surface echo height measurement circuit for measuring the height of the echo, a surface echo height determination circuit for determining the height of the echo measured by the surface echo height measurement circuit, and the surface echo Surface echo height judgment value setting circuit for supplying a judgment value to the height judgment circuit, a central echo height measuring circuit for measuring the height of the echo taken out from the central gate circuit, and the central echo A central echo height determination circuit that determines the height of the echo measured by the height measurement circuit, a central echo height determination value setting circuit that supplies a determination value to the central echo height determination circuit, and a transmission The surface echo height measured by the surface echo height measurement circuit for each repetition is added, and the surface echo height averaging circuit for calculating an average value thereof, and the surface echo height averaging circuit calculates the average value. Surface part average echo height judgment circuit for judging the surface part average echo height, surface part average echo height judgment value setting circuit for supplying a judgment value to the surface part average echo height judgment circuit, and the surface part echo Equipped with a display circuit that displays the judgment results of the height judgment circuit, the central echo height judgment circuit, and the surface average echo height judgment circuit. An ultrasonic flaw detection device characterized by performing flaw detection by setting different echo height determination values. 2. The ultrasonic flaw detector according to claim 1, wherein the average echo height of the surface echo of the test body is measured and judged.