JP3200188B2 - Magnetic particle flaw detector - Google Patents

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 layer of a welded portion of a steel pipe or the like by using magnetic powder. Can be used as a two-pole inter-electrode flaw detector if used separately, and can be used as a four-pole flaw detector if used integrally, and the magnetic powder can be sprayed simultaneously during magnetization. Accordingly, the present invention relates to a magnetic particle flaw detection device which is capable of efficiently performing flaw detection of a complicated shape or a narrow portion.

[0002]

2. Description of the Related Art In a conventional portable magnetic particle inspection device, a magnetizing device, a magnetic particle supply device, and a lighting device are separately and independently provided. As a magnetic particle inspection test procedure, an object to be inspected is magnetized by a magnetizer, and magnetic particles are generated during the magnetization. Is generally applied to the object to be inspected, and thereafter, a magnetic powder pattern on the object to be inspected is observed by a lighting device.

Conventionally, as a magnetizing device using the pole method, a two-pole magnetizing device using an integrated two-pole electromagnet or an integrated four-pole magnetizing device has been used.
A four-pole magnetizing device using a pole electromagnet is generally used, and a three-pole magnetizing device is proposed in Japanese Utility Model Laid-Open No. 3-57663, and a stick type magnet using one rod-shaped electromagnet. There is also a magnetic particle flaw detector.

[0004] As a reference, (a) JIS
G 0565 Magnetic particle flaw detection test method for iron and steel materials, (B) Japan Non-Destructive Inspection Association, Non-Destructive Inspection Handbook, 586-623
Page, Nikkan Kogyo Shimbun (Showa 42), and the like.

[0005]

In the above prior arts, the magnetizing devices are all integrated, and no consideration is given to restrictions on the positioning of the magnetizing device with respect to the object due to the shape and dimensions of the magnetizing device. As shown in (1), when the welded part 20 to be inspected is in a narrow part, the application is difficult or the operation is complicated. Further, since the magnetizing device and the magnetic powder supply device are independent, the flaw detector separately sprays the magnetic powder during the magnetization with a spray or the like, separately from the magnetic powder spraying.

FIG. 4 shows an example of flaw detection by a conventional apparatus. Welding section 20 shown in FIG.
As shown in FIG. 4, in the case of the two-pole type or the stick type, it was necessary to magnetize and scatter magnetic powder four times and to observe four times. On the other hand, in the case of a three-pole or four-pole magnetizing device, only one magnetization, dispersion of magnetic powder and observation are sufficient.
As shown in the figure, one end of each of a number of small diameter pipes 18 is penetrated through the pipe wall of the header (mother pipe) 19, and the small diameter pipe 18 and the header 19 are welded to each other at the penetration. 20
The device to be inspected is
And could not be applied.

A first object of the present invention is to efficiently inspect inspection locations, such as the above-described welded portions of small-diameter pipes, where the conventional apparatus has been impossible or difficult to apply. It is an object of the present invention to provide a magnetic particle flaw detector capable of easily obtaining soundness evaluation.

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

[0009]

According to the present invention, in order to achieve the first object, a welded portion of a steel pipe or the like is magnetized by an electromagnet, and leakage magnetic flux generated by a scratch on a surface or a surface layer is detected by using magnetic powder. A magnetic particle flaw detector that evaluates the soundness of a welded part by performing two magnetizers of the same structure, each magnetizer being an integral part of two magnetic poles formed by winding a magnetized coil around an iron core A magnetic pole block, a gripping piece for gripping the magnetic pole block, and a magnetizing current strong supply switch disposed near an end of the gripping piece. The two magnetizers can be magnetically connected by using an end face of a magnetic piece which is cantilevered to each of the magnetic pole blocks and can be used as a two-pole inter-electrode flaw detector. Used as an integrated 4-pole flaw detector The structure of the magnetic particle apparatus capable.

In order to achieve the second object,
In the present invention, a spray nozzle for dispersing 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 via the spray nozzle. Thus, the magnetic particle flaw detection device is configured to be capable of dispersing the magnetic particles to the inspection target while supplying the magnetizing current to the magnetizing coil.

[0011]

The magnetizing circuit of the magnetic particle flaw detector according to the present invention consists of two types. One is a magnetizing circuit for magnetizing between two integrated poles, and has an electric circuit for magnetizing two magnetic poles.
The other is a magnetizing circuit for magnetizing between the four poles, which is the same as a conventional four-pole magnetizing device, but is of a split type, in which a divided portion is connected to form a magnetic circuit. The principle is to have a plurality of electric circuits for magnetizing two magnetic poles having different directions among the four poles, and to magnetize each of them independently with their phases shifted. In this state, the two magnetizers are joined at the dividing point to form a magnetic circuit between the four integrated magnetic pole portions, and furthermore, the magnetic fields in two orthogonal directions are continuously generated due to the phase shift. Can be
It is possible to detect defects in all directions with one magnetization. 2 poles, 4
The poles are used by switching the switches.

On the other hand, the magnetic powder supply control device comprises a pump for dispersing magnetic powder, a magnetic powder solution tank with a solution stirrer, and a spray nozzle. The pump is operated by a control command signal, and the magnetic powder is automatically discharged from the spray nozzle attached to the magnetizing device. Spray it. First, such a magnetizing device is divided into two poles and inserted into each of the inspection locations, and the connecting portions provided on the two magnetizers are integrated into a single unit, so that even a narrow portion can be easily and efficiently used. Performs magnetic particle testing. The connection portion can be easily aligned by the uneven shape or the like formed on the end face.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A shows the overall configuration of the present embodiment,
(B) is a detailed perspective view of a part A in the figure (a), and (c) is a detailed perspective view of a part B in the figure (a). In FIG. 1A, 1 is a magnetic pole block 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 of the gripping piece 2. A magnetizing current supply switch 4 disposed 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 interpole magnetizing device. Similarly, two magnetic poles 5-
A magnetic pole block 1 'integrally connecting 3, 5-4;
The gripping piece 2 'for gripping the magnet, the magnetizing current supply switch 3', and the magnetic piece 4 'constitute a second magnetizer that can be used as a two-pole interpole magnetizing device. Each magnetic pole 5-1
As shown in FIG. 5B, each of Nos. To 5-4 has a configuration in which a magnetized coil 9 is wound around an iron core 8 and a waterproof treatment layer 10 is further provided thereon. The magnetic pieces 4 and 4 'are used to connect the first and second magnetizers by bringing their respective end faces into contact with each other so that the magnets can be used as an integrated four-pole magnetizer. 4 is provided with a pole on the convex side at the time of alignment in the center of the end face, and the other 4 'is provided with a hole on the center of the end face on the concave side. Reference numeral 6 denotes a magnetizing current power supply for supplying a magnetizing current to the magnetizing coil 9. Reference numeral 7 denotes a magnetizing current supply switch 3 for connecting the magnetizing current power supply 6 and the magnetizing coil 9 to each other.
3 '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 dispersing magnetic powder attached to the magnetic pole blocks 1 and 1', and a magnetic powder supply pipe 12 for supplying magnetic powder to these spray nozzles. A control valve 13 disposed in the middle of the pipe to adjust the amount of the magnetic powder solution, a pump 14 serving as a driving source for feeding the magnetic powder solution, a magnetic powder tank 15 containing the magnetic powder solution, a stirrer 16, a pump 14
And a magnetic powder supply control unit 17 that controls the supply of the magnetic powder by controlling the drive of the stirrer 16. Although not shown, a control command line for giving a control command to the magnetic powder supply control unit 17 is connected to a switch provided near the magnetizing current supply switches 3, 3 'of the magnetizer. When the switch is turned on, a control command signal is input to the magnetic powder supply control unit 17, and the control operation is started.

As a specific example of the use of the apparatus having the above-described configuration, as shown in FIGS.
An example will be described in which a welded portion 20 in which a large number of tubes are implanted by welding into a tube wall of a large-diameter header (base tube) 19 is welded by a four-pole gap-type flaw detection method. Here, FIG. 2A is a perspective view showing an arrangement relationship between the small-diameter pipe 18 and the header 19.
FIG. 2B is an enlarged view of a portion C in FIG. 2A and is a perspective view showing the arrangement of the four-pole gap method apparatus of the present embodiment. First, the two magnetizers are gripped by the respective gripping parts 2, 2 'and inserted into the target welded parts and set. Then, the magnetic material pieces of each magnetizer (FIG. 1)
(4, 4 ') are brought into contact with each other to integrate the two magnetizers. In this case, since the end face of the magnetic piece has an uneven structure at the center, positioning can be easily performed, and the end faces can be abutted without requiring fixing such as fastening.
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 portion.

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 magnet powder supply pipe 12 is connected to the pump 14 via the control valve 13. 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 an opening degree corresponding to quadrupole detection. When the magnetizing current supply switches 3 and 3 'are turned on and the magnetizing coils 9 of the magnetic poles 5-1 to 5-4 are energized, lines of magnetic force are generated on the surface and the surface layer of the welded portion 20. At this time, since the two magnetizers are already connected by the magnetic pieces 4 and 4 'and the four poles form an integrated magnetic circuit, the generated magnetic field lines also have four poles of magnetic force. 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, the magnetic fields 5-1 to 5 are 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. As described above, the magnetic field is generated in all directions within the range surrounded by the four poles, and the magnetization operation required for the flaw detection can be completed with one magnetization. In this state, the stirrer 1
The magnetic powder liquid 21 sufficiently stirred in 6 is fed by the pump 16 and sprayed to the inspection locations by the spray nozzles 11 and 11 ', so that the magnetization and the magnetic powder spraying are performed simultaneously. After supplying the magnetizing current for a time necessary for forming the magnetic powder pattern, the magnetizing current supply switches 3, 3 'are turned off, and the magnetic pieces 4, 4' connecting the two magnetizers are separated to separate the magnetic powder pattern. Observe.

A case will be described in which the present embodiment is used as a two-pole magnetic particle flaw detector. One of the two magnetizers, for example, the first having the magnetic poles 5-1 and 5-2
Of the magnetizer is set at the position to be inspected by holding the grip portion 2. Magnetizing current supply cable 7 for this first magnetizer
Is connected to a magnetizing current power supply unit 6 to set the power supply unit to a power supply corresponding to bipolar magnetization, and the magnetic powder supply pipe 12 of the first magnetizer is connected to a control valve 13 to open the control valve. Set the degree to the degree of opening corresponding to two-pole spraying. Then, when the magnetizing current supply switch 3 is turned on and the magnetizing coil 9 of the first magnetizer is energized 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, the magnetic powder is automatically sprayed on the magnetic field. After the magnetic powder pattern is formed on the surface of the test object, the magnetizing current supply switch 3 is turned off, the drive of the pump 14 is stopped, and the supply of the magnetic powder solution is stopped, and the magnetic powder pattern is observed.

[0018]

According to the present invention, the magnetizing device has a structure which can be used as a magnetizing device by a normal two-pole method by dividing the magnetizing device into two parts. And then connected to form an integrated four-pole magnetizing device, which is efficient for narrow inspection locations such as small-diameter pipe welds, which were difficult to apply in the past. Magnetic particle flaw inspection can be performed, which has a great effect on soundness evaluation of welds. In addition, spray the magnetic powder to the location to be inspected, and fix the spray nozzle to the magnetizer in a fixed manner.
By applying a magnetic powder solution to this spray nozzle from a pump that is driven and controlled in accordance with a control command, it is possible to automate the spraying of magnetic powder that was conventionally performed manually by an inspector by spraying. In addition, the magnetization and the scattering of the magnetic particles can be performed at once, and the efficiency of the magnetic particle flaw detection inspection can be improved. In addition, the apparatus of the present invention has a wide range of application, such as being applicable to inspection of welded parts in general because the mechanism is simple and compact.

[Brief description of the drawings]

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

2 (a) is a perspective view showing a relationship between a small-diameter pipe to be welded and a large-diameter header, and FIG. 2 (b) is a perspective view in FIG. It is a perspective view which shows the expansion relationship of C part, and arrangement | positioning relationship of this Example apparatus.

FIG. 3 is a diagram illustrating a magnetic field generated by the apparatus according to the embodiment.

FIG. 4 is a diagram showing a magnetic pole arrangement at the time of magnetic particle flaw 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 piece 5-1 to 5-4: magnetic pole 6: magnetizing current power supply section 7: magnetization Current supply cable 8 ... Iron core 9 ... Magnetizing coil 10 ... Waterproofing layer 11, 11 '... Spray nozzle 12 ... Magnetic powder supply pipe 13 ... Control valve 14 ... Pump 15 ... Magnetic powder tank 16 ... Stirrer 17 ... Magnetic powder supply control unit 18 ... Small diameter pipe 19 ... Header (base pipe) 20 ... Welded part 21 ... Magnetic powder liquid

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 27/72-27/90

Claims (2)

(57) [Claims] 1. A magnetic particle flaw detector which magnetizes a welded portion of a steel pipe with an electromagnet and detects the leakage magnetic flux caused by a scratch on the surface or surface layer using magnetic powder to evaluate the soundness of the welded portion. 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 disposed near an end of the gripping piece And a switch for each magnetizer, which can be used independently as a two-pole inter-electrode flaw detector, and an end surface of a magnetic piece attached to each of the magnetic pole blocks in a cantilever manner. A magnetic particle flaw detection apparatus characterized in that two magnetizers are magnetically connected by contacting each other to enable use as an integrated four-pole flaw detection apparatus. 2. A magnetic powder solution stored in a magnetic powder tank at a location to be inspected via the spray nozzle, further comprising a spray nozzle for spraying magnetic powder attached to each of the magnetic pole blocks. A magnetic particle supply control device for controlling the supply of magnetic particles, whereby the magnetic powder can be sprayed to a portion to be inspected while a magnetizing current is being supplied to the magnetizing coil.