JP2001099818A - Ultrasonic flaw detection device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic flaw detection device for performing ultrasonic flaw detection by continuous running operation and for recording accurate data even if an SH wave is used. SOLUTION: The film thickness stability retention time of a contact medium 7 is stored in advance by a main control part 50 of the ultrasonic flaw detection device, stop time before performing the ultrasonic flaw detection of an ultrasonic probe 10 being stopped at a data collection position is obtained, the stop time is compared with the film thickness stability retention time, it is judged whether the stop time is longer than the film thickness stability retention time or not, and the start for measuring ultrasonic data and position data is instructed the excess of the stop time over the film thickness stability retention time as a condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flaw detector used for non-destructive inspection, and more particularly to optimal control of probe movement and data recording timing in flaw detection using shear waves. And a flaw detection method.

[0002]

2. Description of the Related Art A conventional automatic ultrasonic flaw detector comprises an ultrasonic probe, a probe scanning device, a control recording unit and a display unit of a flaw detection result. Have been collected.

FIG. 6 is a functional block diagram of a conventional automatic ultrasonic flaw detector. The ultrasonic probe 100 is held by the probe pressing mechanism 110, and mechanically travels on the object to be inspected by the operation of the traveling mechanism 150 on which the motor 130 is mounted.

[0004] The motor control unit 140 controls the stop of driving of the motor 130. The position signal generated by the encoder 170 attached to the traveling mechanism 150 is transmitted to the position signal receiver 20.
0 and is displayed on the position display unit 210. The transmission / reception of the ultrasonic wave to / from the ultrasonic probe 100 is performed by the ultrasonic transmission / reception unit 220.
The ultrasonic data and the position signal data are recorded in the ultrasonic inspection data recording unit 240.

In sequence control, as shown in FIG. 7, when the driving of the traveling mechanism is started in step 300,
Data recording is started immediately (400). After the start of the operation, the traveling mechanism is driven (310), a position signal is read (320), and the traveling mechanism is read until the position signal becomes equal to a preset end position. The drive unit is continuously driven at a constant speed (330), and when the position signal becomes equal to a preset end position, the drive of the traveling mechanism unit is stopped (34).
0), and then stop data recording (440).

In data recording, a position signal is input (410), and when a position signal is input, a preset data collection position is confirmed (420). The position synchronous data recording for recording the data is performed (430), and the process of returning to the state of step 410 waiting for the input of the position signal is repeated again.

The above ultrasonic flaw detection is an effective method when a relatively low viscosity viscous couplant such as longitudinal wave or transverse wave SV wave is used. Flaw detection data is obtained.

However, shear wave (Shear Wav)
e Horizontal (hereinafter abbreviated as SH wave) when performing ultrasonic flaw detection, in order to transmit ultrasonic waves from the ultrasonic probe to the surface of the object to be inspected, a highly viscous contact having a viscosity of about 40 to 1500 Pa · s. It is necessary to use a medium, and the conventional method cannot perform automatic ultrasonic testing.

In recent years, basic research using SH waves and research on defect detection characteristics have been advanced. However, there has been no report on the results of manual flaw detection or automatic flaw detection using a low viscosity couplant. Wave-based flaw detection has not solved the difficulties of having to use a highly viscous couplant.

In ultrasonic flaw detection using SH waves, since a highly viscous couplant is used, it takes a certain time for the echo height, that is, the peak value to stabilize. Therefore, there is a problem that the peak value is not stable in the automatic ultrasonic flaw detection by the continuous running operation, and accurate data cannot be recorded.

As described above, the conventional automatic ultrasonic flaw detection method is directed to a transverse wave SV or a longitudinal wave (L wave) using a low-viscosity couplant, and an SH wave which requires the use of a highly viscous medium. In the flaw detection, these automatic ultrasonic flaw detection methods cannot be used.

One solution is disclosed in Japanese Patent Application Laid-Open No. Hei 10-318998, in which an SH wave probe holding / pressing mechanism and a high viscosity couplant injected under pressure as a couplant supply method are disclosed. And a method for obtaining a stable film thickness by applying pressure to the probe, but there is no description for continuously collecting data, so that this method cannot perform automatic ultrasonic testing.

[0013]

An object of the present invention is to provide an SH
It is an object of the present invention to provide an ultrasonic flaw detection apparatus and a flaw detection method capable of performing ultrasonic flaw detection by continuous running operation even when using waves and recording accurate data.

[0014]

In order to achieve the above-mentioned object, the ultrasonic flaw detector according to the present invention is characterized in that the film thickness holding time of the couplant is stored in advance and stopped at the data collection position. A stop time before performing the ultrasonic flaw detection of the ultrasonic probe is determined, and the stop time is compared with the film thickness stable holding time to determine whether the stop time is longer than the film thickness stable hold time. And instructing the start of the measurement of the ultrasonic data and the position data on condition that the stop time is longer than the film thickness stable holding time.

Specifically, the present invention provides the following apparatus and method. The present invention provides an ultrasonic probe that transmits ultrasonic waves toward an object to be inspected and receives the ultrasonic waves reflected from the object to be inspected, and the ultrasonic probe that holds the ultrasonic probe and A probe pressing mechanism for pressing a probe against the object to be inspected, a traveling mechanism for scanning the ultrasonic probe including the probe pressing mechanism over the object to be inspected, and driving the traveling mechanism A motor control unit that controls, a position signal receiving unit that receives a position signal indicating a position of the ultrasonic probe on the inspection object,
An ultrasonic transmitting / receiving unit that transmits / receives the ultrasonic wave to / from the ultrasonic probe, and an ultrasonic flaw detection unit that stores ultrasonic data received by the ultrasonic transmitting / receiving unit and data using the received position signal as position data. In an ultrasonic flaw detector having a data recording unit and a main control unit for controlling drive control to the traveling mechanism unit and recording timing of the ultrasonic data and the position data, the main control unit includes a couplant. The film thickness stable holding time is stored in advance, the stop time before performing the ultrasonic flaw detection of the ultrasonic probe stopped at the data collection position is obtained, and the stop time and the film thickness stable holding time are compared. And determining whether the stop time is longer than the film thickness stable holding time, and the ultrasonic data and the position are provided on condition that the stop time is longer than the film thickness stable holding time. To provide an ultrasonic flaw detection apparatus characterized by instructing the start of measurement over data.

Further, according to the present invention, an ultrasonic probe is stopped at a data collection position on an object to be inspected, an ultrasonic wave is transmitted toward the object to be inspected, and the ultrasonic wave reflected from the object to be inspected is reflected. In the ultrasonic inspection method for inspecting the inspection object based on the ultrasonic data and the position data of the data collection position, the contact held between the ultrasonic probe and the inspection object surface The film thickness stabilization holding time required to stabilize the film thickness of the medium is stored in advance, and the stop time before performing the ultrasonic flaw detection of the ultrasonic probe stopped at the data collection position is measured, It is determined whether the measured stop time is longer than the film thickness stable holding time, and the measurement of the ultrasonic data and the position data is performed on condition that the stop time is longer than the film thickness stable holding time. And recording To provide an ultrasonic flaw detection method for.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ultrasonic flaw detection apparatus and a flaw detection method according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a functional block diagram of an ultrasonic flaw detector according to an embodiment of the present invention. The ultrasonic testing apparatus transmits an ultrasonic wave toward the inspection object 5 and receives an ultrasonic wave reflected from the inspection object 5, and holds the ultrasonic probe 10 at a constant pressure. Ultrasonic probe 1 always
0, a probe pressing mechanism 11 for pressing 0 to the inspection object 5, a traveling mechanism unit 15 for scanning the ultrasonic probe 10 including the probe pressing mechanism 11 on the inspection object 5, and a traveling mechanism unit 15. , A motor control unit 14 for supplying electric power and a signal for driving the motor, and an electric signal corresponding to an operation amount of the traveling mechanism unit 15, that is, the ultrasonic probe 10 on the inspection object 5. Encoder 17 for generating position signal indicating position
, A position signal receiving unit 20 that receives a position signal from the encoder 17, a position display unit 21 that displays the position signal received by the position signal receiving unit 20 as position data, and an ultrasonic wave to the ultrasonic probe 10. Ultrasonic transmitting and receiving unit 2 for transmitting and receiving data
2, an ultrasonic flaw detection data storage unit 24 that stores the ultrasonic data received by the ultrasonic transmission / reception unit 22 and data obtained by using the position signal received by the position signal reception unit 20 as position data,
A main control unit 50 that controls the drive control to the traveling mechanism unit 15 and the timing of recording the ultrasonic data and the position data.
It is composed of

Also, A couplant 7 for transmitting ultrasonic waves is held between the ultrasonic probe 10 and the surface of the test object 5.

FIG. 2 is a functional block diagram of the main control unit 50 of FIG. The main control unit 50 includes a storage unit 501 that previously stores a probe pressing holding time required for stabilizing the thickness of the couplant 7, that is, a film thickness stabilizing holding time, The measuring unit 502 for measuring the stop time before the ultrasonic flaw detection of the probe 10 is compared with the stop time of the ultrasonic probe 10 and the stable holding time of the thickness of the couplant 7. Determining means 503 for determining whether or not the time is longer than the stable holding time; and instructing means 5 for instructing the start of the measurement of the ultrasonic data and the position data on condition that the stop time is longer than the film thickness stable holding time.
04.

FIG. 3 is a flowchart of the ultrasonic flaw detection sequence control performed by the ultrasonic flaw detector of FIG. The sequence control is first started by pressing the button for automatic flaw detection in step 60, and the traveling mechanism 15 is driven first (61). At the same time as the operation of the traveling mechanism unit 15 starts, the position signal from the encoder 17 is read (62), and it is determined whether or not the data collection position is a preset data collection position (6).
3) If the position is not the data collection position, the driving operation is further continued. If the position is the data collection position, the scanning mechanism is stopped (64).

After the scanning mechanism unit 15 stops, the elapsed time is measured by the measuring unit 501 of the main control unit 50, and the measured time is stored in the storage unit 502 in advance. The scanning mechanism unit 15 is kept stopped until the probe pressing holding time ts at which the thickness of the couplant 7 formed between the scanning mechanism unit 5 and the stabilizing member 7 stabilizes reaches (65).

Here, in the case of performing ultrasonic flaw detection using a shear wave (SH wave), a viscosity of about 40 to 1500 Pa · s is required for transmitting ultrasonic waves from the ultrasonic probe to the surface of the object 5 to be inspected. It is necessary to use the couplant 7 having a high viscosity.

As described in the Lecture Papers of the 4th Nondestructive Evaluation Symposium by Ultrasound, edited by the Japan Nondestructive Testing Association, the thickness of the couplant formed in the gap between the ultrasonic probe and the surface of the test object. As shown in FIG. 4, the relationship between the echo height and the echo height is known to sharply decrease as the film thickness increases.

However, the relationship between the film thickness and the echo height depends on the viscosity of the couplant. FIG. 5 shows the relationship between the pressing time and the echo height when the probe is pressed against the test object.
As shown in (2), the echo height gradually increases and saturates as the pressing time elapses. Assuming that the time until the echo height stabilizes is ts, it is necessary to have a holding time longer than ts in order to collect accurate data as ultrasonic flaw detection, but this time varies depending on the viscosity of the couplant.

As described above, the film thickness of the couplant 7 formed between the ultrasonic probe 10 and the test object 5 depends on the probe gap amount, the viscosity of the couplant 7 to be used, and the probe. It is determined by the relationship between the pressing pressure and the temperature of the flaw detection environment.

The relationship between the type of the couplant and the factors affecting the sensitivity of the SH wave, such as the film thickness and the stabilization time, and the sensitivity are determined in advance by experimental data, and the time ts at which the incidence of the ultrasonic wave is stabilized is determined. Is set, and after the elapse of the time ts, the ultrasonic data and the position data are collected and stored by the ultrasonic flaw detection data recording unit (66). For example, when the SHN-21 type is used as the couplant, the probe pressing holding time ts until the echo height is stabilized is set to 3 minutes or more as shown in FIG.

After the storage of the ultrasonic data and the position data is completed, the main control unit 50 determines whether the position signal is a preset flaw detection end position (67). The driving mechanism 15 is driven again to stop the automatic flaw detection at the end position (6).
8).

As described above, the probe pressing holding time ts
Is set, the scanning control is set to intermittent scanning, and a sequence of these series of operations is continuously controlled to enable ultrasonic flaw detection using SH waves.

[0030]

According to the present invention, even if an SH wave is used, ultrasonic inspection can be performed by a continuous running operation and accurate data can be recorded, so that the reproducibility of the ultrasonic inspection can be improved. In addition, the ultrasonic inspection is less affected by the skill of the inspector.

Further, by optimizing the viscosity of the couplant used, the probe pressing pressure, and the probe gap amount, the probe pressing holding time can be shortened, and the relatively high-speed intermittent scanning can be performed. The flaw detection of the method becomes possible.

[Brief description of the drawings]

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

FIG. 2 is a functional configuration diagram of a main control unit 50 of FIG.

FIG. 3 is a flowchart of sequence control of ultrasonic inspection performed by the ultrasonic inspection apparatus of FIG. 1; FIG. 4 is a diagram showing the relationship between the thickness of the couplant and the sensitivity.

FIG. 4 is a diagram showing the relationship between the thickness of the couplant and the echo height.

FIG. 5 is a diagram illustrating a relationship between a probe pressing time and an echo height.

FIG. 6 is a functional configuration diagram of a conventional automatic ultrasonic flaw detector.

FIG. 7 is a flowchart of the sequence control of the automatic ultrasonic flaw detector of FIG. 6;

[Explanation of symbols]

5 ... inspected object, 7 ... couplant, 10 ... ultrasonic probe, 1
DESCRIPTION OF SYMBOLS 1 ... Probe pressing mechanism, 13 ... Motor, 14 ... Motor control part, 15 ... Traveling mechanism part, 17 ... Encoder, 20 ... Position signal receiving part, 21 ... Position display part, 22 ... Ultrasonic transmission / reception part, 24 ... Ultrasonic flaw detection data storage unit, 50: main control unit, 501: storage unit, 502: measurement unit, 503: determination unit, 504: instruction unit

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoji Yoshida 3-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Ibaraki Hitachi Information Service Co., Ltd. No. 2 Hitachi Engineering Co., Ltd. F term (reference) 2G047 CB02 EA09 GA05 GA19 GE01 GG19 GJ28

Claims (2)

[Claims] An ultrasonic probe for transmitting an ultrasonic wave toward an object to be inspected and receiving the ultrasonic wave reflected from the object to be inspected; and an ultrasonic probe holding the ultrasonic probe and holding the ultrasonic probe. A probe pressing mechanism for pressing a probe against the object to be inspected, a traveling mechanism for scanning the ultrasonic probe including the probe pressing mechanism over the object to be inspected, and a traveling mechanism. A motor control unit that controls driving, a position signal receiving unit that receives a position signal indicating a position of the ultrasonic probe on the object to be inspected, and an ultrasonic unit that transmits and receives the ultrasonic wave to and from the ultrasonic probe. An ultrasonic wave transmitting and receiving unit, an ultrasonic flaw detection data recording unit that stores ultrasonic data received by the ultrasonic transmitting and receiving unit and data that is the received position signal as position data, and drive control to the traveling mechanism unit and A method for controlling the timing of recording the ultrasonic data and the position data. An ultrasonic flaw detector having an application control unit, wherein the main control unit preliminarily stores the thickness stabilization holding time of the couplant and performs ultrasonic flaw detection of the ultrasonic probe stopped at a data collection position. The stop time is determined, and the stop time is compared with the film thickness stable hold time to determine whether the stop time is longer than the film thickness stable hold time. An ultrasonic flaw detector which instructs the start of measurement of the ultrasonic data and the position data on condition that the holding time is longer. 2. An ultrasonic probe is stopped at a data collection position on an object to be inspected, ultrasonic waves are transmitted toward the object to be inspected, and ultrasonic data of the ultrasonic waves reflected from the object to be inspected. An ultrasonic flaw detection method for flaw-detecting the inspection object based on the position data of the data collection position and the thickness of the couplant held between the ultrasonic probe and the surface of the inspection object. The film thickness stabilization holding time required for stabilizing is stored in advance, and the stop time before performing the ultrasonic flaw detection of the ultrasonic probe stopped at the data collection position is measured. It is determined whether or not the time is longer than the film thickness stable holding time, and the measurement and recording of the ultrasonic data and the position data are performed on condition that the stop time is longer than the film thickness stable holding time. Ultrasonic testing characterized by performing Method.