JPS6048700B2 - Surface wave method ultrasonic flaw detection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In surface technique ultrasonic flaw detection, the present invention divides the entire surface of a material to be inspected into fixed areas, detects the number of flaws and the flaw length per each area, and detects the number of flaws and the flaw length based on this. This invention relates to a surface technique ultrasonic flaw detection device that evaluates flaws for each area.

In surface technique ultrasonic flaw detection, when the flatness of the surface of a material to be inspected is poor, if flaws on the material to be inspected are evaluated only by echo height, the evaluation accuracy cannot be said to be sufficient.

This is because the correlation between flaws on the material to be inspected and the corresponding echo heights is not good. The purpose of the present invention is to detect flaws in a material to be inspected using a surface technique ultrasonic flaw detection method, and to evaluate defects in the material to be inspected, the entire surface of the material to be inspected is divided into fixed evaluation areas. The object of the present invention is to provide an apparatus that calculates the number of flaws and flaw length for each evaluation area, performs flaw evaluation for each evaluation area based on this, and further evaluates the entire test material. . In addition, the gist of the present invention is that in a surface wave method ultrasonic flaw detection device that evaluates the entire surface of a test material by moving the probe and the test material relative to each other: Compare the signal detected by the probe with a set level. Furthermore, a gate level waveform shaper that forms this signal waveform; a movement detection circuit that detects the relative movement between the test material and the probe and converts it into an electrical signal; and a reference length signal. a reference signal generator that generates; a flaw counting circuit that receives a signal from the gate level waveform shaping circuit and counts the number of flaws; and a flaw counting circuit that receives an AND signal of the gate level waveform shaping circuit and the movement amount detection circuit. a flaw length counting circuit that counts the flaw length; an arithmetic device that receives signals from the flaw number counting circuit and the flaw length counting circuit and calculates a flaw evaluation value; an output device that outputs the signal from the arithmetic device; The flaw evaluation value is calculated for each evaluation area that is divided into specified gate widths and standard lengths in the ultrasonic propagation direction of the test material and the direction perpendicular to this, and then This is a surface wave method ultrasonic flaw detection device that performs flaw evaluation on the entire surface of a test material based on the following.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory diagram showing one embodiment of the present invention.

In the figure, 1 is a test material and 2 is a probe. Probe 2
The ultrasonic waves emitted from the probe propagate in the direction of the dotted arrow, that is, perpendicular to the transport direction of the test material, and the effective flaw detection distance thereof is, for example, about 6007 m. In this example, this effective flaw detection distance is divided almost equally into 6 parts, and from the probe side G, .
G.・・・・・・G. I will call it . Moreover, the above-mentioned G,,G.・・・・・・G. The width is called the gate width.
Generally, the direction of conveyance of the test material is the same as the longitudinal direction of the test material. However, for convenience of evaluation, the test material is divided into standard lengths Δ1 along this direction. The evaluation area is therefore (
It has a size of (gate width) x (reference length). In this embodiment, the gate width is approximately 100 mm, and the reference length is approximately 40 mm. Now, as shown in FIG. 2, it is assumed that there are three flaws on the material to be inspected, for example, at locations corresponding to G and the gate.

When ultrasonic waves are emitted from the probe 2 without relative movement between the test material 1 and the probe 2, a reflected wave is generated that is reflected by the flaw 3. For example, when this relationship is displayed on a cathode ray tube, it becomes as shown in FIG. In the figure, 4 indicates an incident (outgoing) wave, and 5 indicates a reflected wave. Further, for example, when a test material is transported and an ultrasonic wave is transmitted perpendicular to the transport direction, the reflected waveform from a flawed part of the test material will be referred to as an analog output.

When several flaws are clustered together as shown in FIG. 2, this analog output becomes OFF as shown at 6 in FIG. 4. The echo height H2 of the analog output is approximately equal to the maximum echo height H of the reflected waves in FIG. 3, and its width is indicated by the time u corresponding to the longest flaw length 1 of the flaws 3. have size. If the distance between the flaws is wide, the output from the hole will be as shown in Figure 5a.

Next, FIG. 6 is a block diagram illustrating an embodiment of the flaw evaluation apparatus according to the present invention.

10 is a flaw detection device that outputs the analog output.

The gate level waveform shaper 11 inputs the analog J-log output, compares the input signal with a set level determined for quality control or noise countermeasures, and picks up a signal corresponding to a defect exceeding a specified value, Further, this is formed into, for example, a rectangular pulse. This is shown in Figure 5c. The output signal of the gate level waveform shaper 11 is applied to a flaw number counter 12 and an AND circuit 21. Although this analog output signal does not completely correspond to the number of defects on the material to be inspected when the density of defects is high as explained above, for convenience, the number of this signal is taken as the number of defects. 18 is a measuring roll that detects the amount of movement accompanying the conveyance of the test material.

The pulse generator is engaged with the measuring roll and converts the amount of movement of the test material into an electrical signal. The output signal of the pulse generator is transmitted to an amplifier 2.
0 to the ΛND circuit 21 and constant distance counter 22, the waveform of which is shown in FIG. 5b. The constant distance counter 22 counts the number of pulses corresponding to the reference length Δ1, and when this value is reached, provides a signal to the one shot pulse generator 23. A signal shaped, for example, into a rectangular pulse by a one-shot pulse generator 23 is applied to gate circuits 13, 25 and delay timers 16, 28. Now, as mentioned above, the signals from the amplifier 20 and the gate level waveform shaper 11 (shown in FIGS. 5B and 5C, respectively) are input to the AND circuit 21. The output is as shown in Figure 5d.

Here, it is shown that the logical product b is calculated and the number of pulses proportional to the flaw length is output. This pulse signal is
It is added to the flaw length counter 24 and counted only during the time corresponding to the reference length. When a time corresponding to the reference length has elapsed, a pulse is sent from the one shot pulse generator 123 to open the gate of the gate circuit 25. Then, the value counted by the flaw length counter is sent to the buffer memory 26, and further to the D/A converter 27 and the amplifier 29.
is input to the arithmetic unit 30 via. Further, the pulse from the one shot pulse generator 23 is delayed by, for example, about 200 msec by a delay timer 28 and then applied to the flaw length counter 24 to reset the flaw length counter 24. In this way, the flaw length in a certain section is determined. Similarly, the number of flaws is determined.

As mentioned above, the signal from the gate level waveform shaper 11 is applied to the flaw number counter 12, and the number of flaws counted here is determined by the signal from the one shot pulse generator 23 when the flaw detection of the standard length is completed. The pulse opens the gate of the gate circuit 13 and is stored in the buffer memory 4. Immediately thereafter, the flaw counter 12 is reset by a pulse signal applied via the delay timer 16. The information of the buffer memo January 4 is input to the arithmetic unit 30 via the D/A converter 15 and the amplifier 17.
FIG. 7 is a diagram illustrating an example of a calculation method. The flaw number signal from the amplifier 17 is applied to comparators 32 to 34, and in this embodiment, three setting levels L, , M, , H,
Classification is performed. 'Similarly, the flaw length signal from the amplifier 29 is applied to the comparators 35 to 37 to set the level L in three stages. , Corner, H. Classification is performed. The output of each comparator is set such that, for example, if the input signal is larger than the set level, there is an output, and if it is smaller, there is no output. The respective outputs from the comparison circuits 32 to 37 are input to a logic circuit included in the signal processing circuit 38. The output of this logic circuit is performed as shown in FIG. 8, for example, so that evaluation can be performed with weight placed on either the number of flaws or the length of flaws. or,
Methods different from the embodiments described above, e.g. comparators 32-34
It is also preferable to multiply the outputs of the outputs and the outputs of the comparators 35 to 37 by different coefficients, add them together, and further compare and classify the outputs with set values.

Furthermore, instead of the outputs of the comparators 32 to 34 and the outputs of the comparators 35 to 37, output signals from the amplifiers 17 and 29 may be added, respectively. In the above-mentioned embodiment, the information regarding the number of flaws and the flaw length is inputted to the calculation device 30 as an analog signal. A method of inputting the information to the device 30 may also be used.

In short, a certain gate Gi (i=1, 2,...
6), a certain reference length section Δ1i (i=1, 2,...
The number of flaws and flaw length within the evaluation unit area corresponding to n) are detected, and this information is processed by the arithmetic unit 30. The result is
Any method can be said to be suitable for carrying out the present invention as long as it is capable of performing arithmetic processing that has a correct correlation with the actual flaw condition of the inspected material.

Now, the result of calculation for each evaluation area by the calculation device 30 is an output signal of the calculation device 30, and is added to the display device 31.

The display device 31 includes, for example, a high-speed multiplexer, and samples the input signal from the arithmetic device 30 for each evaluation area and displays it. Further, the calculation device 30 stores calculation results for each evaluation area, and calculates a flaw pattern for the entire surface of the material to be inspected. Then, by comparing with predetermined conditions, for example, the condition of defects on the entire surface of the material to be inspected, the condition of defects in the center of the material to be inspected, etc. are determined, and post-process processing such as determining the quality of the material to be inspected and commanding the entire surface scarf is performed. Establish. This determination is outputted via the printer 40, for example. As described above, according to the apparatus of the present invention, it is possible to evaluate a test material using the surface wave ultrasonic flaw detection method in an online manner, and the evaluation accuracy is extremely high.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view showing an embodiment of the present invention, Fig. 2 is a schematic plan view showing an example of a flaw situation on a test material, and Fig. 3 is a diagram showing relative movement between the test material and the probe. 4 and 5 a are graphs showing an example of the analog output by the device of the present invention, and FIG. 5c is a graph similarly showing the output from the gate level waveform shaper 11, FIG. 5d is a graph showing the output of the AND circuit 21, and FIG. 6 is a graph showing the flaw evaluation device according to the present invention. FIG. 7 is a block diagram illustrating an embodiment of the arithmetic device 30 of the present invention.
FIG. 8 is a diagram illustrating the logical judgment of the signal processing device. 1: Test material, 2: Probe, 3: Flaw, 4: Incident wave, 5: Reflected wave, 6: Analog output, 10: Flaw detection device, 11: Gate level waveform shaper, 12: Flaw number counter, 13: Gate circuit, 14: Buffer memory, 15: D/A converter, 16: Delay timer, 17: Amplifier, 18: Measuring roll, 19: Pulse generator, 20: Amplifier, 21: AND circuit, 22: constant distance counter, 23: one shot pulse generator, 24 flaw length counter, 25: gate circuit, 26: buffer memory, . 27: D/A converter, 28: Delay timer, 29: Amplifier, 30: Arithmetic device, 31: Display device, 32 to 37: Comparator, 38: Signal processing circuit, 40: Printer, G,, G2 ，・・・・・・
G6: Gate width, Δ1: Reference length.

Claims (1)

[Claims] 1 In a surface wave method ultrasonic flaw detection device that evaluates the entire surface of a test material by moving the probe and the test material relative to each other: The signal detected by the probe is compared with the set level, and the signal waveform is a gate level waveform shaper that forms a signal; a movement detection circuit that detects the relative movement between the test material and the probe and converts it into an electrical signal; and a reference signal generator that generates a reference length signal. a flaw number counting circuit that receives a signal from the gate level waveform shaping circuit to count the number of flaws; and a flaw counting circuit that receives an AND signal of the gate level waveform shaping circuit and the movement amount detection circuit to count the flaw length. a length counting circuit; an arithmetic device that receives signals from the flaw number counting circuit and the flaw length counting circuit to calculate a flaw evaluation value; and an output device that outputs the signal from the arithmetic device; A flaw evaluation value is calculated for each evaluation area of the material to be inspected, which is divided into specified gate widths and standard lengths in the direction of movement and in the direction perpendicular to this, and based on this, the evaluation value is calculated for the entire surface of the material to be inspected. A surface wave method ultrasonic flaw detection device characterized by performing flaw evaluation.