JPS6145186B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic particle flaw detection device that detects the presence and position of defects by attracting magnetic particles to leakage magnetic flux.

Conventional magnetic particle testing is explained using the case of detecting cracks in weld beads as an example.
As shown in d. First, base material (material to be tested) 1
Directly spray magnetic particles 3 or a test solution consisting of magnetic particles suspended in kerosene or water onto the bead portion 2 (first step).
(see figure a). Thereafter, the flaw detection electrode 4 is placed on the base material 1 so as to straddle the bead portion 2, and the base material 1 is magnetized by the flaw detection electrode 4 by applying electricity from the magnetization power source 5. When a defect 7 exists, magnetic flux leaks from this defect and attracts magnetic particles, creating a magnetic particle pattern (see FIG. 1b). This magnetic particle pattern is observed with the naked eye under ultraviolet rays emitted from the black light 6 (see FIG. 1c). After the observation is completed, the magnetic particles are removed by air injection or the like (see Figure 1d). In this way, conventional magnetic particle flaw detection tests involve directly scattering or applying magnetic particles or test liquid to the material to be detected, and then magnetizing it, which not only makes the work of dispersing, removing, and cleaning the magnetic particles troublesome, but also reduces the amount of magnetic particles used. It is difficult to reuse and wastes resources. Furthermore, it is difficult to automate flaw detection work.

The present invention aims to provide a magnetic particle flaw detection method and apparatus that enable highly efficient and automated magnetic particle flaw detection and do not consume magnetic particles.

The configuration of the present invention to achieve such an object is to encapsulate a test liquid in which magnetic particles are suspended in kerosene or water in a flexible belt whose inner peripheral surface is made of a transparent material; Constructing an endless track, disc-shaped magnetized electrodes are arranged on both sides of the endless track to contact the surface of the object to be inspected and run at the same speed as the endless track, so that continuous magnetic particle flaw detection can be performed. It is characterized by

The configuration of the present invention will be described in detail below based on embodiments shown in the drawings.

An example of a magnetic particle flaw detection device is shown in FIGS. 2 to 6. The apparatus consists of a flexible belt 10 that encloses a test liquid, a drive system for the belt 10, a magnetization system, and a monitoring system that observes magnetic particle patterns. The flexible belt 10
As shown in FIG. 6, a transparent flexible thin film 10A is provided on the inner surface to enable observation of the magnetic particle pattern.
In addition, a white flexible thin film 10B is adopted on the outer surface so that the magnetic particle pattern can be clearly seen.
The test liquid 11 is sealed between these 10A and 10B in a bag shape. Said transparent flexible thin film 10A
The white flexible thin film 10B is made of synthetic resin, such as nylon, and the white flexible thin film 10B is made particularly thin so that it hardly affects defect detection performance, that is, allows leakage magnetic flux to pass through well. has been done. In addition, this flexible belt 10
Holes 12 are perforated at a constant pitch on both side edges to facilitate the transmission of driving force.

The flexible belt 10 is supported by being hung around three idler wheels 13 and one driving wheel 14 supported by a casing (not shown). The rotation of the drive wheel 14, which is rotated by the drive motor 31 in synchronization with the electrode wheel 17, is transmitted to the flexible belt 10 via the protrusion 15 that fits into the hole 12 of the flexible belt 10. .

The magnetization system for magnetizing the material 1 to be tested is a magnetization power supply 1.
8. It consists of an electrode holding member 19, two magnetized electrodes 17 made of rotating disks, and a pressurizing rubber ring 20 that presses the flexible belt 10 against the material 1 to be tested.
The magnetization electrode 17 rolls on the material 1 to be flaw-detected, continuously magnetizing the material 1 to be flaw-detected, and also functions as a driving wheel of the magnetic particle flaw detection device. In addition, the rotation is gear 2
1 and 22 from the drive motor 16. Further, the pressurized rubber ring 20 is provided so that gas is pressurized into the inside so that the circumferential surface thereof bulges out slightly.

The monitoring system includes a monitor television camera 23, a monitor receiver 24, and a recording video tape recorder 25. The magnetic particle pattern drawn by the test liquid 11 inside the flexible belt 10 under the influence of leakage magnetism is photographed by the above-mentioned monitor television camera 23 and is displayed on the monitor receiver 2.
4, the presence or absence of defects and their locations can be detected and recorded. Note that the monitor television camera 23 is fixed to a casing (not shown) and photographs the flexible belt at a certain position.
Further, the monitor receiver 24 and the recording video tape recorder 25 may be installed at separate locations.

With the above configuration, if the flexible belt 10 containing the inspection liquid forming an endless track is placed on the material 1 to be tested and the material 1 to be tested is magnetized by the wheel-shaped magnetization electrode 17, defects can be detected. The magnetic particles in the test liquid 11 are attracted to the leakage magnetic flux generated in the portion, forming a magnetic particle pattern. In particular, a pressurized rubber ring 20 is placed between the magnetizing electrodes 17.
Since the belt 10 is brought into close contact with the material 1 to be inspected, it is strongly influenced by leakage magnetic flux and forms a clear magnetic particle pattern. When this magnetic particle pattern reaches the bottom of the monitor television camera 23 as the belt 10 moves, it is projected onto the monitor receiver 24 by the same camera 23, so that the operator can check whether there is a defect, its position, and its shape. You can know. Recording is also performed by the video tape recorder 25. In this magnetic particle flaw detection test, a belt 1 containing test liquid 11 is used.
Since 0 is an endless track, it is possible to perform it continuously.

Therefore, pre- and post-processing operations such as scattering and collection of magnetic powder are unnecessary. Moreover, it is possible to carry out flaw detection work automatically and continuously. This has made it possible to significantly increase efficiency and automate the continuous inspection of longitudinal seam joints of electric resistance welded pipes, for example, for the inspection of long products. It also contributes to resource conservation because there is no consumption of magnetic powder.

Other embodiments are shown in FIGS. 7 and 8. Components having the same configuration as those of the previous embodiment are given the same reference numerals and explanations will be omitted.

In this embodiment, a flexible belt 10 containing a test liquid 11 is formed into a cylindrical shape, and both peripheral edges of the flexible belt 10 are fixed to support disks 26 to form a tire-like structure. The internal pressure of the wheel 27 made of the flexible belt 10 is set slightly higher than the external pressure so that the circumferential portion (belt 10 portion) swells outward. Therefore, the belt 10 closely follows the surface irregularities of the material 1 to be tested. A monitor television camera 23 is installed inside this wheel 27.
The monitor television camera 23 is fixed to the electrode holding member 19 and monitors the flaw detection material 1 regardless of the rotation of the wheel 27.
The contact portion of the belt 10 is always displayed. Note that a seal such as an O-ring 30 is applied to the rotating portion between the wheel 27 and the rotating shaft 28 or the camera support shaft 29. Furthermore, if the monitor television camera 23, drive motor 16, etc. are watertightly treated, it can be effectively used as an underwater magnetic particle detection device. However, the magnetizing power supply 18 and the monitor receiver 24
A video tape recorder 25 is also installed on the ocean.

According to the device of this embodiment, a flexible belt (container) 1 that can be seen from the outside as in the previous embodiment
Since the test liquid is sealed in the 0, there is no need for pre-processing work such as scattering and collection of magnetic particles, and since the flexible belt 10 forms an endless track, flaw detection work can be carried out automatically and continuously. is possible. In particular, if watertight treatment is applied, underwater magnetic particle testing becomes possible. In addition, there is no consumption of magnetic particles, contributing to resource conservation.

[Brief explanation of the drawing]

1A to 1D are explanatory diagrams showing a conventional magnetic particle flaw detection test method, FIG. 2 is a schematic perspective view showing an example of a magnetic particle flaw detection apparatus according to the present invention, and FIG. 3 is a view taken along arrow A-A in FIG. A sectional view, FIG. 4 is a sectional view taken along the line B-B in FIG. 2,
FIG. 5 is a perspective view of a flexible belt containing a test liquid, and FIG. 6 is a sectional view taken along the line C--C showing the structure of the belt. FIG. 7 is a central vertical cross-sectional view schematically showing another embodiment of the magnetic particle flaw detection device, and FIG. 8 is a central cross-sectional view of the same. In the drawing, 10 is a flexible belt (flexible container),
11 is a test liquid, 17 is a magnetization wheel, and 23 is a monitor television camera.

Claims (1)

[Claims] 1. A test solution in which magnetic particles are suspended in kerosene or water is enclosed in a flexible belt whose inner peripheral surface is made of a transparent material, while the flexible belt constitutes an endless track, and both sides of the endless track are A magnetic particle flaw detection apparatus characterized in that disk-shaped magnetized electrodes are respectively disposed in contact with the surface of the test object and run at the same speed as the endless track, so that magnetic particle flaw detection can be performed continuously.