JPH0694679A - Magnetic flaw detector - Google Patents

Abstract

PURPOSE:To realize a magnetic flaw detector capable of being inserted in the narrow place such as the welded part formed when a large number of small caliber pipes are implanted in a large caliber header (matrix pipe) by welding to enable magnetization due to a quadrupole interpole method and capable of automatically sprinkling a magnetic powder to a place to be inspected during magnetization. CONSTITUTION:Each of two magnetizers independently becomes a two-pole interpole type magnetizing device by providing a magnetic pole block 1 (1') wherein two magnetic poles are integrated, the grasping piece 2 (2') grasping the block and the magnetizing current supply switch 3 (3') arranged to the grasping piece. Two magnetizers are connected by making the end faces of the magnetic element pieces 4, 4' fixed to the magnetic pole blocks abut on each other to constitute an integrated type quadrupole magnetizing device. Further, a magnetic powder supply control device sprinkling a magnetic powder to a place to be inspected through the spray nozzles 11, 11' attached to the magnetic pole blocks is provided to constitute a magnetic powder flaw dector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic particle flaw detector for detecting flaws on the surface or surface of a welded portion of a steel pipe using magnetic powder, and more particularly to a magnetizer for detecting flaws in a narrow area that cannot be detected by a conventional apparatus. Can be used as a 2-pole inter-pole flaw detector if used separately, and can be used as a 4-pole flaw detector if used in an integrated manner. Further, magnetic powder can be dispersed at the same time during magnetization. As a result, the present invention relates to a magnetic particle flaw detection device capable of efficiently performing flaw detection on a complex shape or a narrow portion.

[0002]

2. Description of the Related Art In a conventional portable magnetic powder flaw detector, a magnetizing device, a magnetic powder supplying device, and an illuminating device are separately provided. As a magnetic powder flaw detecting test procedure, a magnetizer magnetizes an object to be inspected, and the magnet powder is magnetized during the magnetization. The procedure of sprinkling the object on the object to be inspected and then observing the magnetic powder pattern on the object to be inspected with an illumination device is generally performed.

As a magnetizing device according to the pole-to-pole method, conventionally, a two-pole type magnetizing device using an integral two-pole electromagnet or an integral type four-pole magnetizing device is used.
A 4-pole magnetizing device using a pole electromagnet is generally used, and a 3-pole magnetizing device is proposed in Japanese Utility Model Laid-Open No. 3-57663. Furthermore, a stick type magnet using a single rod-shaped electromagnet is used. There is also a magnetic particle flaw detector.

The reference documents are (a) JIS
G 0565 Magnetic particle flaw detection test method for steel materials, (b) Nondestructive Inspection Handbook, edited by Japan Nondestructive Inspection Association, 586-623
Page, Nikkan Kogyo Shimbun (Showa 42), and the like.

[0005]

In each of the above-mentioned prior arts, the magnetizing device is of an integral type, and no consideration is given to the restriction of alignment with the object due to the shape and size of the device. When the welded portion 20 which is the object to be inspected is in the narrow portion as shown in (4), the application is difficult or the operation is complicated. Further, since the magnetizing device and the magnetic powder supplying device are independent, a flaw detector separately sprays the magnetic powder during magnetization by spraying or the like.

FIG. 4 shows an example of flaw detection by a conventional device. The welding part 20 shown in FIG.
As shown in FIG. 4, it was necessary to magnetize 4 times, and in the case of the two-pole type or the stick type, 4 times of magnetization and spraying of magnetic particles, and further 4 times of observation. On the other hand, with a three-pole or four-pole magnetizing device, it is sufficient to perform one-time magnetization, spraying of magnetic particles, and observation.
A welded portion when one end of a large number of small-diameter pipes 18 is penetrated through the pipe wall of the pipe header (mother pipe) 19 and the small-diameter pipes 18 and the header 19 are welded at the penetrating portions as shown in FIG. 20
For the one to be inspected, the device is
Could not be applied and could not be applied.

A first object of the present invention is to efficiently inspect an inspection point such as the above-mentioned welded portion of a small-diameter pipe where the conventional apparatus cannot be applied or is difficult. An object is to provide a magnetic particle flaw detector that allows easy evaluation of soundness.

A second object of the present invention is to improve the conventional magnetic powder supply procedure in which a flaw detector sprays magnetic powder during magnetization by spraying or the like, so that magnetic powder can be automatically supplied during magnetization. It is to provide a magnetic particle flaw detector equipped with a magnetic powder supply control device.

[0009]

In order to achieve the first object of the present invention, a magnetic flux is detected by magnetizing a welded portion of a steel pipe or the like with an electromagnet and a magnetic flux is used to detect a leakage magnetic flux. In the magnetic particle flaw detector for evaluating the soundness of the welded portion, the two magnetizers having the same structure are provided, and each magnetizer integrally includes two magnetic poles formed by winding a magnetizing coil around an iron core. A magnetic pole block connected to the magnetic pole block, a gripping piece for gripping the magnetic pole block, and a magnetizing current strong-feeding switch arranged near the end of the gripping piece. The magnetizer can be used as a two-pole inter-pole flaw detector, and the two magnetizers are magnetically connected by abutting the end faces of the magnetic pieces that are cantilevered on the magnetic pole blocks. Used as an integrated 4-pole flaw detector The structure of the magnetic particle apparatus capable.

In order to achieve the above second object,
In the present invention, a spray nozzle for spraying magnetic powder is attached to each of the magnetic pole blocks, and a magnetic powder supply control device for controlling the supply of the magnetic powder solution stored in the magnetic powder tank is provided at a location to be inspected through the spray nozzle. As a result, the magnetic particle flaw detector is configured so that the magnetic powder can be sprayed to the inspected portion while the magnetizing current is being supplied to the magnetizing coil.

[0011]

The magnetizing circuit of the magnetic particle flaw detector according to the present invention comprises two types. One is a magnetizing circuit that magnetizes the two poles that are integrated, and has an electric circuit that magnetizes two magnetic poles.
The other is a magnetizing circuit for magnetizing between the four poles, which is the same as the conventionally used four-pole magnetizing device, but since it is of a split type, it connects the splitting portions to form a magnetic circuit. The principle is to have a plurality of electric circuits that magnetize two magnetic poles of the four poles that are in mutually different directions, and magnetize each independently while the phases are shifted. In this state, by joining two magnetizers at the dividing points, a magnetic circuit is formed between the integrated four-pole magnetic pole portions, and the magnetic fields in two orthogonal directions are continuously generated because the phases are shifted. Can be
Defects can be detected in all directions with a single magnetization. 2 poles, 4
The poles are used by switching the switches.

On the other hand, the magnetic powder supply control device comprises a magnetic powder spraying pump, a magnetic powder solution tank with a solution stirring device, and a spraying nozzle. The magnetic powder is automatically supplied from a spraying nozzle attached to the magnetizing device by operating the pump in response to a control command signal. Spray. First of all, such a magnetizing device is divided into two poles, each of which is inserted up to the inspected portion, and the connecting portions provided on the two magnetizers are combined into one body, which allows the use of the magnet easily and efficiently even in narrow spaces. Magnetic particle testing can be performed. The connection portion can be easily aligned due to the shape of the irregularities formed on the end surface.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a diagram showing the overall configuration of this embodiment,
(B) is a detailed perspective view of the A section in the (a) figure, and (c) is a detailed perspective view of the B section in the (a) figure. In FIG. 1A, 1 is a magnetic pole block formed by integrally connecting two magnetic poles 5-1 and 5-2, 2 is a gripping piece for gripping the magnetic pole block 1, and 3 is a gripping piece 2. A magnetizing current supply switch 4 arranged near the end is a magnetic piece attached to the magnetic pole block 1 in a cantilever manner.
2, 3, and 4 constitute a first magnetizer that can be used as a two-pole interpolar magnetizing device. Similarly, two magnetic poles 5-
A magnetic pole block 1'in which 3, 5-4 are integrally connected,
The holding piece 2'for holding this, the magnetizing current supply switch 3 ', and the magnetic piece 4'constitute a second magnetizer that can be used as a two-pole interpolar magnetizing device. Each magnetic pole 5-1
As shown in FIG. 5B, the magnets 5 to 5-4 each have a structure in which a magnetizing coil 9 is wound around an iron core 8 and a waterproof treatment layer 10 is further provided on the magnetizing coil 9. The magnetic pieces 4 and 4 ′ are for connecting the first and second magnetizers by abutting their respective end faces so that they can be used as an integrated quadrupole magnetizing device. A pole on the convex side at the time of alignment is provided in the center of the end face of 4, and a hole on the concave side is provided in the center of the end face of the other 4 '. Reference numeral 6 denotes a magnetizing current power supply unit that supplies a magnetizing current to the magnetizing coil 9, and reference numeral 7 denotes the magnetizing current power supply unit 6 and the magnetizing coil 9 for the magnetizing current supply switch 3,
It is a magnetizing current supply cable connected via 3 '.

On the other hand, the magnetic powder supply control device includes spray nozzles 11 and 11 'for spraying magnetic powder, which are attached to the magnetic pole blocks 1 and 1', respectively, and a magnetic powder supply pipe 12 for supplying magnetic powder to these spray nozzles. A control valve 13 arranged in the middle of the pipe for adjusting the amount of the magnetic powder solution, a pump 14 as a drive source for feeding the magnetic powder solution, a magnetic powder tank 15 storing the magnetic powder solution, an agitator 16, and a pump 14.
And a magnetic powder supply control unit 17 that controls magnetic powder supply by drivingly controlling the stirrer 16. Although not shown, the control command line for giving a control command to the magnetic powder supply control unit 17 is connected to a switch installed in the vicinity of the magnetizing current supply switches 3 and 3'of the magnetizer. However, when this switch is turned on, a control command signal is input to the magnetic powder supply control unit 17 to start the control operation.

As a concrete example of the use of the apparatus having the above-mentioned structure, as shown in FIGS.
An example will be described in which the welded portion 20 in the case of implanting a large number of the above into the pipe wall of the large-diameter pipe header (mother pipe) 19 by welding is performed by the four-pole interelectrode flaw detection method. Here, FIG. 2A is a perspective view showing a positional relationship between the small-diameter pipe 18 and the header 19.
(B) is an enlarged view of a C portion in (a) and is a perspective view showing the arrangement of a 4-pole interelectrode method apparatus of the present embodiment. First of all, the holding parts 2 and 2'of the two magnetizers are held and inserted into the target welding part and set. Then, the magnetic piece of each magnetizer (see FIG.
4 and 4 ') are brought into contact with each other to integrate the two magnetizers. In this case, since the end surface of the magnetic piece has a concave-convex structure in the central portion, the alignment can be easily performed, and both end surfaces can abut without requiring fixing such as tightening.
In addition, since the two magnetizers can be integrally rotated while being connected, the installation position can be easily adjusted according to the shape of the inspected part.

Next, the other end of the magnetizing current supply cable 7 is connected to the magnetizing current power supply section 6, and the other end of the magnetic powder supply pipe 12 is connected to the pump 14 via the adjusting valve 13, and then the magnetizing current is supplied. The power supply unit is set to a power supply corresponding to quadrupole magnetization, and the opening degree of the control valve 13 is set to the opening degree corresponding to quadrupole flaw detection. When the magnetizing current supply switches 3 and 3'are turned on to energize the magnetizing coils 9 of the magnetic poles 5-1 to 5-4, lines of magnetic force are generated on the surface and the surface layer of the welded portion 20. At this time, the two magnetizers are already connected by the magnetic material pieces 4 and 4'and the four poles form an integrated magnetic circuit. Therefore, the generated magnetic field lines also have four poles. It corresponds to. That is, as shown in FIG. 3, the magnetic field has a time difference depending on the phase, and as shown in FIG. 3, 5-1 to 5 centered on the intersection of the line connecting the magnetic poles 5-1 and 5-3 and the line connecting 5-2 and 5-4.
It occurs in the range of the square of -4. In this way, the magnetic field is generated in all directions within the range surrounded by the four poles, and the magnetizing work required for flaw detection can be completed with one magnetization. In this state, the stirrer 1 in the magnetic powder tank 15
The magnetic powder solution 21 sufficiently stirred in 6 is sent by the pump 16 and sprayed to the inspected places by the spray nozzles 11 and 11 ', so that the magnetization and the magnetic powder spraying are simultaneously performed. After supplying the magnetizing current for the time required to form the magnetic powder pattern, the magnetizing current supply switches 3 and 3'are turned off, and the magnetic material pieces 4 and 4'connecting the two magnetizers are separated from each other to form the magnetic powder pattern. Observe.

A case where the apparatus of this embodiment is used as a two-pole inter-pole type magnetic particle flaw detector will be described. One of the two magnetizers, for example, a first magnet having magnetic poles 5-1 and 5-2.
The magnetizer of (1) is set at the location to be inspected by holding the grip 2. Magnetizing current supply cable 7 of this first magnetizer
Is connected to the magnetizing current power supply unit 6 to set the power supply unit to a power supply corresponding to the two-pole magnetization, and the magnetic powder supply pipe 12 of the first magnetizer is connected to the control valve 13 to open the control valve. Set the degree to the degree of opening that corresponds to the 2-pole application. Then, when the magnetizing coil 9 of the first magnetizer is energized by driving the magnetizing current supply switch 3 to drive the pump 16 to supply the magnetic powder solution, a magnetic flux is generated between the magnetic poles 5-1 and 5-2. At the same time, magnetic particles are automatically dispersed in the magnetic field. After the magnetic powder pattern is formed on the surface of the inspection object, the magnetizing current supply switch 3 is turned off, and the pump 14 is stopped to stop the supply of the magnetic powder solution to observe the magnetic powder pattern.

[0018]

According to the present invention, the magnetizing device is of a two-division type, and has a structure that can be used alone as a magnetizing device by a normal two-pole method, and these two magnetizers are to be inspected. Since it is configured as an integrated quadrupole magnetizing device after being set to, it is efficient even for narrow inspection points such as small-diameter pipe welds that were difficult to apply in the past. Magnetic particle inspection can be performed, which has a great effect on the integrity evaluation of welded parts. Furthermore, for spraying magnetic powder to the inspected area, the spray nozzle is fixedly attached to the magnetizer.
The magnetic powder solution is sent to this spray nozzle from a pump that is driven and controlled according to a control command, so it is possible to automate the magnetic powder spraying that was conventionally performed by an inspector by manually spraying. It is possible to perform the magnetization and the magnetic powder spraying at once, and it is possible to improve the efficiency of the magnetic powder flaw detection inspection. Further, since the device of the present invention has a simple and compact mechanism, it can be applied to inspection of welded parts in general, and thus has a wide range of application.

[Brief description of drawings]

FIG. 1 is an embodiment diagram of the present invention, in which FIG.
(B) is a detailed perspective view of the A section in the (a) figure, and (c) is a detailed perspective view of the B section in the (a) figure.

2A and 2B are explanatory views of specific examples of the present invention, in which FIG. 2A is a perspective view showing a relationship between a small diameter pipe to be welded and a large diameter pipe header, and FIG. It is a perspective view which shows the expansion of C section, and the arrangement | positioning relationship of a present Example apparatus.

FIG. 3 is a diagram showing a magnetic field generated by the device of this embodiment.

FIG. 4 is a diagram showing a magnetic pole arrangement at the time of magnetic particle flaw detection inspection by a conventional apparatus.

[Explanation of symbols]

1, 1 '... Magnetic pole block 2, 2' ... Gripping piece 3, 3 '... Magnetizing current supply switch 4, 4' ... Magnetic material pieces 5-1 to 5-4 ... Magnetic pole 6 ... Magnetizing current power supply section 7 ... Magnetization Electric current supply cable 8 ... Iron core 9 ... Magnetizing coil 10 ... Waterproofing layer 11, 11 '... Spray nozzle 12 ... Magnetic powder supply piping 13 ... Control valve 14 ... Pump 15 ... Magnetic powder tank 16 ... Stirrer 17 ... Magnetic powder supply control unit 18 … Small diameter pipe 19… Heading (mother pipe) 20… Welding part 21… Magnetic liquid

Claims (2)

[Claims] 1. A magnetic particle flaw detector that evaluates the soundness of a welded part by magnetizing a welded part of a steel pipe with an electromagnet and detecting leakage magnetic flux generated by scratches on the surface or surface using magnetic particles. It has two magnetizers, each magnetizer
A magnetic pole block formed by integrally connecting two magnetic poles formed by winding a magnetizing coil around an iron core, a gripping piece for gripping the magnetic pole block, and a magnetizing current supply arranged near the end of the gripping piece. And a magnet switch, each magnetizer can be used independently as a two-pole interpole flaw detector, and the end face of the magnetic piece cantileverly attached to each magnetic pole block. The magnetic particle flaw detector is characterized in that the two magnetizers are magnetically connected to each other by being brought into contact with each other so that it can be used as an integrated quadrupole flaw detector. 2. The magnetic powder solution according to claim 1, further comprising a spray nozzle for spraying magnetic powder attached to each magnetic pole block, and a magnetic powder solution stored in a magnetic powder tank at a location to be inspected through the spray nozzle. By providing a magnetic powder supply control device for controlling the supply of the magnetic powder, it is possible to disperse the magnetic powder to the inspected portion while supplying the magnetizing current to the magnetizing coil.