JPS59197857A - Ultrasonic flaw detector - Google Patents

Abstract

PURPOSE:To constitute a titled flaw detector so that its flaw detection impossible range is not increased and an echo is not misconceived by detecting in advance a flaw detecting path, determining a flaw detecting gate time for detecting a flaw, and making total opening time of a position detecting gate means opened successively coincide with the flaw detecting gate time. CONSTITUTION:In a flaw detecting gate time determining means, a flaw detecting depth of a member to be flaw-detected is detected in advance, and also a flaw detecting gate time corresponding to its flaw detecting depth is determined. In a position detecting gate control means, a total opening time of a position detecting gate means is made to coincide with its flaw detecting gate time. Therefore, the position detecting gate means is controlled so that the total opening time of the position detecting gate means is made to coincide exactly with the flaw detecting time determined in advance at every member to be flaw- detected. It is not caused that a flaw detection impossible range and a flaw detection leakage thereby are increased and it is misconceived as a bottom face echo, inspite of a variance of size of the member to be flaw-detected, a change of the quality of material, etc., and an exact ultrasonic flaw detection is obtained.

Description

Detailed Description of the Invention Technical Field The present invention relates to an ultrasonic flaw detection device, and in particular, to detect the location of flaws existing in a flaw detection target regardless of variations in the dimensions of the flaw detection target or changes in the material of the flaw detection target. The present invention relates to a technique for reliably grasping to which region of a predetermined depth direction the object belongs.

・Conventional technology An ultrasonic probe that injects ultrasonic waves in the depth direction of a component to be tested, detects reflected echoes reflected from within the component to be tested, and outputs an echo signal, and an ultrasonic probe that outputs an echo signal; Thereafter, a plurality of position detection gate means are each selectively and sequentially opened to allow the echo signal to pass during the time period, and the position detection gate means is opened based on which of the position detection gate means the echo signal is passed through. 2. Description of the Related Art Ultrasonic flaw detection devices are known that include flaw position detection means for determining the position of flaws in the depth direction. In such a device, the position detection gate means are sequentially opened according to a predetermined opening time, and which of the plurality of regions in the depth direction corresponds to the opening time of the position detection gate means. It is common to determine which wounds belong to. However, according to such a conventional device, the total opening time of the position detection gate means is constant when there are variations in the dimensions of the part to be tested or the material of the part to be tested is changed. When the total opening time and the possible flaw detection time corresponding to the flaw detection depth and thickness of the flaw-detected part do not match, and the undetectable range increases, or the bottom echo of the flaw-detected part is mistaken as a reflected echo due to a flaw. was there.

In other words, in the conventional case where the opening time of the position detection gate means is constant, the presence or absence of flaws is determined only in the depth region corresponding to the opening time. If the dimensions vary in the increasing direction, the detection depth will increase and the detection range will increase.
rJJJ (dead zone) increases, making it more likely that flaws will not be detected.

In addition, if the depth dimension of the part to be tested varies in the decreasing direction, there is a risk that the detection time will decrease and overlap with the opening time of the position detection gate means, and in such a case, the bottom reflection echo will be There were cases in which the received echoes were mistaken for reflected echoes caused by scratches.

・Purpose of the invention The present invention has been made against the background of the above circumstances,
The purpose is to provide an ultrasonic flaw detection device that does not increase the undetectable range due to variations in the dimensions of the part to be detected, changes in material, etc., or that does not misidentify bottom echoes as reflected echoes due to flaws. It's about doing.

・Structure of the Invention In order to achieve the above object, the ultrasonic flaw detection apparatus of the present invention includes the following steps: (1) detecting the flaw detection depth of the flaw-detected member in advance based on the reflected echo from the bottom surface of the flaw-detected member; flaw detection gate time determining means for detecting flaws existing within the flaw detection depth; (2) controlling the open time of the position detection gate means;
The present invention is characterized by comprising: position detection gate control means for making the total opening time of the means for successively opening the position detection gates 1 coincide with the flaw detection gate time.

・Effects of the invention By doing this, as shown in the frame correspondence diagram in FIG. 1, the flaw detection gate time determining means detects the flaw detection depth of the member to be flaw detected in advance and corresponds to the flaw detection depth. While determining the flaw detection gate time, the position detection gate control means matches the total open time of the position detection gate means with the flaw detection gate time. Therefore, since the position detection gate means is controlled to ensure that the total open time of the position detection gate means matches the flaw detection gate time predetermined for each member to be tested, the dimensions (depth This eliminates the possibility of an increase in the undetectable range and the resulting increase in flaw detection omissions, or misidentification as bottom echoes, due to variations in the horizontal direction or changes in the material, resulting in reliable ultrasonic flaw detection. Moreover, even if the sound velocity inside the tested part is affected, such as when the material or temperature of the tested part is changed, this flaw detection system can determine the flaw position based on the arrival time of the reflected echo. ,
This is essentially the same as the variation in dimensions of the part to be tested, so
The same effects as described above can be obtained without requiring the troublesome work of setting the opening time of the position detection gate means.

-Example Hereinafter, an example of the present invention will be explained in detail based on the drawings.

In FIG. 2, reference numeral 10 denotes a rectangular steel material as a member to be tested for flaws, and a plurality of (four in this embodiment) ultrasonic flaw detectors 12 are arrayed in the width direction on the lower side thereof. The ultrasonic probe 12 is composed of a ceramic piezoelectric element or the like, and serves as an ultrasonic transmitter and receiver in a time-sharing manner. However, the ultrasound probe 12 may each include a pair of dedicated transmitter and receiver.

The flaw detection waveform TW received by the ultrasonic probe 12 is amplified by the pulser receiver 14 and then supplied to the gate interval adjustment circuit 16 and the flaw detection gate circuit 18. In addition to this amplification function, the pulsar receiver 14 also has the following functions:
When the trigger signal TR is supplied from the trigger circuit 20, the ultrasonic probe 1 transmits a transmission pulse T for emitting ultrasonic waves.
Supply to 2. As shown in FIG. 3, the gate interval adjustment circuit 16 compares the flaw detection waveform TW with a preset reference level S, detects the transmitted pulse T and the bottom reflection echo Bl, and detects the transmitted pulse T. The time width t from the time to the detection of the bottom surface reflection echo B1. The pulse signal is supplied to the I10 boat 22. The time width t0 corresponds to the depth and thickness of the steel material 10 in the flaw detection direction. The gate interval adjustment circuit 16 also adjusts the flaw detection gate time supplied from the I10 boat 22 and the mask time t□ set in the setting device 24 by adjusting the flaw detection gate time to the flaw detection gate circuit 16.
8 is supplied with gate control GC, and the flaw detection gate circuit 18 is opened for a flaw detection gate time t2 at a predetermined timing.

The reflected echo signal F from the flaw 26 that has passed through the flaw detection gate circuit 8 is stored in the wave memory 28 at a location corresponding to the flaw position. That is, as shown in FIG. 4, the wave memory 28 stores a plurality of (six in this embodiment) gate circuits 30a to 30f as position detection gate means, and the reflected echo signal F that has passed through them. It includes peak bold circuits 32a to 32f that hold peak values, A/D conversion circuits 34a to 34f that convert the held peak values into digital code signals, and memories 36a to 36f that store the converted decile code signals, respectively. It is being

The wave memory 28 further includes a gate circuit 3. A gate controller (roll circuit 38) that selectively and sequentially opens Oa to 301', and an oscillator 4o that supplies a signal with a frequency that determines the opening time to the control circuit 38.
is provided. The oscillator 40 oscillates according to the command frequency signal SF corresponding to the flaw detection gate time t2 supplied from the I10 port 22, and the gate circuits 30a to 30f
are selectively and sequentially opened as shown in FIG. This is done to match the gate time t2. In this embodiment, gate circuits 30a to 30
Since f is the same open time, the open time ratio of each is 1/6. Note that the gate control circuit 38 is reset in accordance with the transmission command signal SA supplied to the trigger circuit 22, and at the same time the gate control circuits 30a to 30f are reset.
A series of signals that sequentially open the gates are sent to each gate circuit 3.
Supply starts from 0a to 30f.

On the other hand, the trigger circuit 20 outputs a trigger signal TR in synchronization with the supply of the transmission command signal SA, and causes the pulser receiver 14 to supply the transmission pulse T to the ultrasound probe 12. and,
A movement sensor 42 consisting of a roller in contact with the steel material 10 and a pulse encoder rotated by the roller is brought into contact with the steel material 10, and the movement sensor 42 outputs a pulse corresponding to the amount of movement of the steel material 10 in the longitudinal direction. A mobile signal SM containing the information is provided to the I10 boat 22.

The setting device 24 has an area for determining whether or not the steel material 10 is acceptable based on the number of transmission pulses 1' generated in synchronization with one pulse of the mobile signal SM and the presence or absence of flaw positions in the cross section of the steel material 10. etc. are now set,
The setting contents are supplied to the I10 boat 22.

The I10 port 22 is connected to the CPU4 via the data bus line.
4. Connected to ROM 46 and RAM 48. C
The PU 44 processes each signal supplied to the 110 boat 22 while utilizing the temporary storage function of the RAM 4.8 according to a program stored in advance in the ROM 46, and outputs a command frequency signal SF, a transmission command signal SA, etc.

The operation of this embodiment will be described below with reference to the flowcharts of FIGS. 6 and 7.

First, prior to flaw detection of the steel material 10, the program shown in FIG. 6 is executed, and the open time of each of the gate circuits 30a to 30f is determined for each steel material 10.

That is, step S1 is executed and the transmission command signal SA
is output, and ultrasonic waves are emitted from the ultrasonic flaw detection probe 12. Then, in step S2, it is determined whether the transmission pulse ``'' has been output according to the signal from the data 1-interval adjustment circuit 16, and if it has been output, step S3 is simultaneously executed and the timer starts timing. The timer starts counting at the rising edge of the output signal from the data 1 to interval adjustment circuit 16 to the I10 boat 22 shown in FIG.
4 is executed to determine the presence or absence of the reflected echo signal B□, in other words, the fall of the output signal from the gate interval adjustment circuit 16 to the I10 port 22.

When the reflected echo signal B is detected, step S5 is executed, the timer is completed, and the time t0 corresponding to the thickness (depth) of the steel material IO is determined.

Next, step S6 is executed, and flaw detection gate time t2
is determined by the following equation.

"2 = tO(t□+j3) However, Ll is a value set in the setting device 24 at a slightly larger time interval than the transmission pulse T, and t
3 is a preset value corresponding to a dead zone existing on the bottom surface of the steel material 10.

Then, a signal representing the flaw detection time t2 determined here and the preset time interval L2 is transmitted to the I10 boat 2.
2 to the gate interval adjustment circuit 16, the gate interval adjustment circuit 16 supplies the gate control signal GC to the flaw detection gate circuit in synchronization with the transmission pulse signal T included in the flaw detection waveform TW. As shown in , the flaw detection gate circuit 18 is opened for a flaw detection gate time t2. Therefore, the time required for steps S5 and S-6 corresponds to the thickness of steel 110. The flaw detection gate time determining means is configured to detect the flaw detection gate time t2 in advance and determine the flaw detection gate time t2 based on the detected flaw detection gate time t2.

Next, step S7 as position detection gate control means
is executed, and the oscillator 4 built in the wave memory 28
The frequency of 0 is determined by the following equation.

(2) However, n is the number of the gate circuits 30a to 30f, and is 6 in this embodiment.

However, in this embodiment, the opening ratios of the gate circuits 30a to 30f are set to be approximately equal by the setting device 24.
Since each is determined to be 1/6, the oscillator 400 frequency is set to 6 times 1/L2, and the command frequency signal SF is supplied from the I10 boat 22 to the oscillator 40 in the waits memory 28 so that the oscillator 40 emits at that frequency. be done. Therefore, the control circuit 38 is connected to the oscillator 4o.
Since the gate circuits 30a to 30f are selectively and sequentially opened as shown in FIG. 5 in accordance with the frequency supplied to the gate circuits, the individual open ratios (1/6) of the gate circuits 30a to 30f are maintained. The total opening time of the flaw detection gate storage time t2 is made to match the flaw detection gate storage time t2.

Therefore, even if there is a change in the dimensions of &RJtA10, variations in dimensions, changes in the 4A quality and temperature of the steel material 10, etc., the area divided in the thickness direction of the steel material 1o corresponding to the opening time of the gate circuits 30a to 3Of. In other words, the deviation in the flaw detection depth of the steel material 10 is automatically set to match the flaw detection gate time t2, so compared to the conventional device in which the open time of the gate circuits 30a to 30f is fixed, the method for the steel material 1o is changed. This eliminates the need for the troublesome work of changing and setting the open time interval of the day 1 circuit every time, and the &FIJ shrine 10 The undetectable area (dead zone) increases, or conversely, the reflected echo from the bottom surface B1
This completely eliminates the problem of F being mistaken for a foul echo F from a wound.

Although it is sufficient to perform the above routine (steps s1 to s7) only once prior to flaw detection of the steel material 10, it may be performed every execution cycle of the steps shown in FIG. 7, which will be described later. In addition, the above routine is executed not only for one ultrasound probe 12 but for all ultrasound probes 12, and the time t required for each routine. is each flaw detection probe■
It may be an average value or a minimum value with respect to 0.

Next, the steel material 10 is made to travel in the longitudinal direction, and at the same time each step in FIG. 7 is executed. That is, step R1 is executed and it is determined whether or not the movement signal SM is generated. The movement signal SM includes a pulse that is periodically generated every time the movement distance of the steel material 10 reaches a predetermined amount. Command signal SA is I10
The signal is supplied from the boat 22 to the trigger circuit 20 . The trigger circuit 20 outputs a trigger signal TR so that the transmission pulse T is supplied from the pulser receiver 14 to the B sonic probe 12. Then, in step R3, it is determined whether the number N of transmitting the transmission pulse T has reached the preset number NO in the setting device 24, and if it has not reached it, steps R2 and subsequent steps are executed again. However, when you reach the next step.

BrR4 is executed. That is, as shown in FIG. 8, each time a pulse of the movement signal SM is generated, a plurality of transmission pulses T are outputted at regular intervals (about 1 ms).

In this state, the flaw detection waveform TW is supplied to the gate interval II node circuit I6 and the flaw detection gate circuit 18 through the pulser receiver 14 every time the transmission pulse "F" is output, so the flaw detection gate circuit 18 is synchronized with the transmission pulse T. Then, the gate interval control circuit 16 opens the flaw detection case 1 for time t3.

Therefore, the foul echo F from the flaw 26 included in the flaw detection waveform 'rW is supplied to the wave memory 28 through the flaw detection circuit 18, and as shown in FIG. The peak value is stored in any one of 36f to 36f. The transmission pulse T is a predetermined constant value N0 times (J゛When it is transmitted, step R
4 is executed, and the contents sequentially stored in the wave memory 28 are read into the RAM 48. That is, the memories 36a to 36f in the wave memory 28 store reflected echoes F for the number of times the transmission pulse T was emitted.
．． 1, and the total stored contents are read into the RAM 48. Note that reading into the RAM 48 may be performed every time the transmission pulse T is output, and the data may be summed within the RAM 48.

Next, step R5 as a flaw position detecting means is executed, and each area in the depth direction of the copper phase 10, in other words, the memory 36
The sum of the peak values of the reflected echoes F stored in areas a to 36f is averaged, and if it is larger than a predetermined constant value, it is determined that a flaw exists in that area. At the same time, the length of the scratch is also determined based on the movement signal SM. In this case, a statistical method may be used in which among the values of the reflected echoes F stored in synchronization with the output of the transmission pulse T, the highest and lowest values are excluded and the remaining values are averaged. In such a case, there is an advantage that abnormal values caused by poor contact of the ultrasonic probe 12 with the steel material 10 or problems are removed, and a reliable flaw signal can be obtained.

Further, the above steps are executed for each of the ultrasonic probes 12, and for each, six steps are performed in the depth direction of the steel material 10.
Since the presence or absence of a flaw is determined in the divided areas, it is determined in which of the 24 divided areas of the cross section of the steel +K 10, as shown in the cross section of the steel material 10 in FIG. 9, the flaw 26 is present. Ru.

Moreover, the determination of the presence or absence of scratches only in a specific region may be excluded by the region setting of the setting device 24, and the pass/fail of the preparation 10 may be determined. For example, if the area near the center of &D+A' 10 is scheduled to be removed by cutting or the like, even if a flaw is detected in the shaded area in the cross section of the steel material 10 in FIG. 1o is judged as passing. When the upper and lower layers of the steel material 10 are scheduled to be cut, the steel material 10 is determined to be acceptable even if a flaw is detected in the shaded area in the cross section of the steel material 10 in FIG. In such a case, there is an advantage that a steel material that has conventionally been rejected for a specific application can be determined to be usable conditionally by clarifying the location of the flaw.

Although the embodiment of the present invention has been described above based on the drawings, the present invention can also be applied to other embodiments.

For example, in the above embodiment, &r4jrAL O may be fixed in position, and the ultrasonic probe 12 may be made to travel along the steel material IO.

Further, the cross section of the steel material 10 may not only be square but also circular. In such a case, it is necessary to use one ultrasonic flaw detection probe and rotate it and the steel material relative to each other.

Further, in the above-described embodiment, the regions divided in the depth direction of the steel material 10 to detect the flaw positions are divided into equal parts, but the regions may be set to be divided into unequal parts.

In such a case, the open time of the gate circuits 30a to 30f corresponding to the divided area may be controlled according to the divided size.

Furthermore, although the flaw detection gate circuit 18 is provided before the wave memory 28 in the above embodiment, the flaw detection waveform TW passing through the flaw detection gate circuit 18 is directly transmitted to the wave memory 28.
8 may be supplied.

Further, in the above-described embodiment, a part of the wave memory 28 (memories 36a to 36f) is also constituted by a microcomputer, and is also constituted by an extremely high-speed A/
When a D converter is applied, peak hold circuits 32a to 32f and gate circuits 30a to 30f are also constructed by a microcomputer.

Note that the above is just one embodiment of the present invention,
The present invention can be modified in various ways without departing from its spirit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram corresponding to claims of the present invention. FIG. 2 is a diagram illustrating the configuration of an ultrasonic flaw detection apparatus showing an embodiment of the present invention. FIGS. 3, 5, and 8 are time charts illustrating the operation of the embodiment of FIG. 2. FIG. FIG. 4 is a Bronk diagram showing the configuration of the wave memory shown in FIG. 2. 6 and 7 are flowcharts illustrating the operation of this embodiment. Figures 9 to 11 show steel material 1o.
FIG. 3 is a cross-sectional view showing areas for detecting flaw positions, respectively. lO: Steel material (member to be tested) 12: Ultrasonic probe 30: a-f gate circuit (position detection gate means) step,
Bu S5. S6: Flaw detection gate time determining means Step S7:
Position detection gate control means Step R5: Flaw position detection means Applicant: Daido Steel Co., Ltd. Figure 1 Q' (Figure 3) Figure 6 Figure 8 Figure 10 Figure 11

Claims (1)

[Scope of Claims] An ultrasonic probe that injects ultrasonic waves in the depth direction of a member to be tested, detects reflected echoes reflected from within the member to be tested, and outputs an echo signal; a plurality of position detection gate means that are selectively and sequentially opened to allow the echo signals to pass during a time period after the incidence of the ultrasonic waves; and a plurality of position detection gate means through which the echo signals are allowed to pass. flaw position detection means for determining to which of a plurality of regions the position in the depth direction of the valence belongs to, based on whether the valence is open, based on the open time of each of the position detection gate means. The flaw depth of the flaw detection target member is detected in advance based on the reflected echo from the bottom surface of the flaw detection target member, and the flaw detection gate time for detecting flaws existing within the flaw detection depth is determined. and a position detection gate control means that controls the opening time of the position detection gate means and makes the total opening time of the position detection gate means that are sequentially opened match the flaw detection gate time. An ultrasonic flaw detection device characterized by: