JPS6258103A - Method for ultrasonic flaw detection - Google Patents

Abstract

PURPOSE:To make it possible to simply inspect the inner surface of a cylindrical object to be inspected within a short time, by filling the cylindrical object to be inspected with a medium pervious to an ultrasonic wave. CONSTITUTION:A cylindrical object 11 to be inspected is filled with a medium 12 pervious to an ultrasonic wave such as oil or water and one vertical ultrasonic probe 13 is provided to the outside of said object 11. When a driving pulse signal is applied to the probe 13 from a transmitter 14, a pulse S is transmitted to the direction shown by an arrow 17 and impinges against the inner surface 11A and inner surface 11B opposed thereto of the object 10 to be reflected while reflected waves SA, SB, SC are received by a receiving part 15. The reflected wave SC is one from the surface 11C. Next, the probe 13 is continuously or intermittently moved over the half periphery of the object 11 to be inspected as shown by an arrow 18 and, every when the probe 13 moves over a predetermined distance, an ultrasonic wave is transmitted from the probe 13. The reflected waves SA, SB at that time are received by the receiving part 15 and imagewise displayed by an image display means 16 based on a C-scope method and the corrosion state over the inner peripheral surface of the object 11 to be inspected can be easily grasped within a short time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an ultrasonic flaw detection method that uses ultrasonic waves to inspect the inner surface condition of, for example, pipelines and underground pipes (including box-shaped pipes). .

[Conventional technology]

Ultrasonic flaw detection is a very simple and practical means of determining the state of corrosion on the inner surface of a pipe, and is therefore widely used. FIG. 4 is a diagram illustrating the conventional ultrasonic flaw detection method, in which a vertical probe 2 is installed outside the tube 1 that is the object to be inspected, and a transmitter (not shown) is attached to the vertical probe 2. Step 1) The thickness of the tube 1 can be measured by sending an ultrasonic wave from the vertical probe 2 by applying a pulse from the vertical probe 2, and by receiving the reflected wave reflected from the inner surface 3 of the tube in the vicinity of the vertical probe 2. The corrosion state of the entire circumference of the inner surface of the tube is inspected by measuring and scanning the entire circumference in the four directions of arrows shown in the figure.

Then, by the means described above, the received signal obtained by scanning the vertical probe 2 over the entire circumference is received by a receiving section (not shown), and then recorded and displayed on recording paper or processed as an image. It is later displayed on the display.

Another conventional ultrasonic flaw detection method is to install a two-dimensional array ultrasonic probe on the outer periphery of the tube 1, and
Each probe of the dimensional array ultrasonic probe is scanned at high speed by an electronic circuit, and the reflected waves are received by the receiver and displayed on the display.

[Problem to be solved by the invention]

However, with these ultrasonic flaw detection methods, when inspecting the entire circumference of the inner surface of a tube, the ultrasonic probe must scan the entire circumference of the outer surface of the tube, making the installation work of the probe complicated. Furthermore, when inspecting a pipe that is buried in the ground or has already been constructed as a structure, digging up the pipe is extremely troublesome, and there is a problem in that the inspection work takes a long time. Ta.

The present invention has been made to solve the above-mentioned problems, and provides an ultrasonic flaw detection method that utilizes the advantages of ultrasonic flaw detection to inspect the inner surface of an object in a simple and shortened inspection time. The purpose is to provide.

[Means for solving problems]

In order to achieve the above object, the present invention fills the inside of a cylindrical object with an ultrasound transmission medium, installs an ultrasound probe on the outside of the object, and connects the ultrasonic probe to the outside of the object. The condition of the inner surface directly facing the object is inspected by transmitting ultrasonic waves and propagating them in the ultrasonic wave J3 application medium to obtain reflected waves on the inner surface of the object.

[Effect]

Therefore, the present invention has the above-mentioned means.
Ultrasonic waves transmitted by an ultrasound probe are transmitted not only to the inner surface of the object immediately adjacent to it, but also to the inner surface facing the object through the ultrasound transmission medium, and reflected waves are obtained from the inner surface of the tube directly facing the object. I can do it. As a result, the entire circumference of the inner surface of the object can be inspected by scanning only half the circumference of the object, and the scanning range is about half that of conventional ultrasonic flaw detection, making flaw detection easy and reducing the work time. It can be significantly shortened.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Fig. 1 is a schematic diagram of an ultrasonic flaw detection apparatus to which the method of the present invention is applied, and Fig. 2 is an explanatory diagram of the operation of Fig. 1. A cylindrical specimen 11 having a circular or square cross-sectional shape is filled with an ultrasound transmission medium 12. For example, oil, water, etc. are used as the ultrasound transmission medium 12. After filling the inside of the object with the ultrasonic transmission medium 12, for example, one vertical ultrasonic probe 13 is installed outside the object 11. 14 transmits a transmission pulse to transmit the ultrasonic probe. 15 is a receiving section that receives a timing signal from the transmitter 15 and then receives a reflected wave reflected from the inner surface of the subject 11; 16 is a receiving signal output from the receiving section 15; This is an image display means that processes and displays the image.As this image display means 17, a conventionally well-known method such as the C scope method (planar figure method) is adopted. This method shows the presence or absence of an echo as the brightness of a single point on the cathode ray tube, and graphically displays the position of the point on the cathode ray tube by moving it in correspondence with the scanning position of the probe.

According to the above-described apparatus, when a driving pulse signal is applied from the transmitter 14 to the ultrasonic probe 13, the ultrasonic probe 13 moves in the direction of the arrow 17 at the timing shown in FIG. A transmission pulse S is transmitted, and this transmission pulse S is reflected by hitting the inner surface 11A closest to the probe, the inner surface 11B on the opposite side facing the inner surface 11A (these surfaces 11A and 11B are referred to as the inner surface facing directly), etc. reflected waves SA, S at the receiver 15 at the timing shown in FIG.
B, receives SC. SC is a reflected wave □ reflected from 11C shown in FIG. G.A.

GB indicates a gate. In this method, the ultrasonic probe 13 is connected to the subject 1 as shown by the arrow 18 in the figure.
The ultrasonic flaw detection method 13 transmits ultrasonic waves every time the ultrasonic flaw detection method 13 moves a predetermined distance while moving continuously or intermittently for half a circumference of 1, and the reflected waves SA and SB at that time are sent to the receiver 16.
By receiving the information and displaying it as an image using the C-scope method using the image display means 16, it is possible to easily grasp the corrosion state of the entire circumference of the inner surface of the subject.

Therefore, according to the method of the embodiment described above, if one ultrasonic probe 13 is moved over half the circumference of the object 11 and the reflected ultrasonic waves are received, the entire circumference of the inner surface of the object is detected. The condition can be grasped, the movement range of the probe 13 is reduced to about half compared to the conventional one, and inspections of, for example, vibrating lines and underground pipes are made very simple, and the working time can be significantly shortened.

In addition, normally, the surface of the object 11 to be inspected is painted in order to suppress corrosion on the outside, and it is necessary to remove the paint film during ultrasonic flaw detection, but the work to remove the paint film is halved. This also greatly contributes to streamlining inspection work. In addition, in the case of underground pipes, it is necessary to dig up the soil, but with this flaw detection method, only half of the soil needs to be dug out of the test object 11, so inspection work can be carried out smoothly. Necessary measures can be taken.

Although one vertical ultrasonic probe was used in the above embodiment, for example, as shown in FIG. 3, a plurality of probes 13
A two-dimensional array ultrasonic probe 13A in which a... are arranged two-dimensionally may be used. The shape of this probe 13A is one formed in advance to match the shape of the subject 11, or one that is planar and flexible, and as a scanning means, a scan controller, a multiplexer, etc. are used. In response to the drive timing signal from the transmitter 14 or its frequency divided signal, the scan controller switches and controls the multiplexer, and each probe element 13a...
All you have to do is select ・ in order to receive the reflected waves.
These techniques use known means.

〔Effect of the invention〕

As described above in detail, the method of the present invention makes it possible to provide an ultrasonic flaw detection method that allows the inspection work of a specimen to be performed relatively easily and allows the work time to be significantly shortened.

[Brief explanation of the drawing]

Figures 1 and 2 are for explaining an embodiment of the ultrasonic scarring method according to the present invention. 2 is an explanatory diagram showing the ultrasonic transmission/reception state, FIG. 3 is a diagram showing another example of an ultrasonic probe, and FIG. FIG. 2 is an explanatory diagram of a conventional ultrasonic flaw detection method. 11... Subject, 12... Ultrasonic transmission medium, 13
...Ultrasonic probe, 14... Transmitter, 15... Receiving section, 16... Image display means. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] (1) Filling the inside of a cylindrical object with an ultrasound transmission medium, and installing an ultrasound probe outside the object;
An ultrasonic flaw detection method characterized by transmitting ultrasonic waves from this ultrasonic probe and receiving the reflected waves to inspect the condition of the directly facing inner surface of the object. (2) The ultrasonic flaw detection method according to claim 1, wherein the ultrasonic probe is one that uses one vertical wave probe. (2) The ultrasonic flaw detection method according to claim 1, wherein the ultrasonic probe device uses a two-dimensional array ultrasonic probe. (4) When the ultrasonic probe device uses one vertical probe, the vertical probe is moved half way around the subject while transmitting ultrasonic waves, covering the entire inner circumference of the subject. The ultrasonic flaw detection method according to claim 1 or 2, which is for inspecting a condition. (5) When the ultrasound probe is a two-dimensional array ultrasound probe, high-speed scanning is performed using scan control,
The ultrasonic flaw detection method according to claim 1 or 3, wherein each ultrasonic probe element is sequentially selected to receive reflected waves.