JPH0633065U - Gap type magnetic flaw detector - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the inspection efficiency without reducing the magnetic flux density entering the inspection object. [Structure] A quadrupole magnetizer 2 composed of N ₁ , N ₂ , S ₁ , and S ₂ that magnetizes the welded structure 1 when energized, a spring 3 that supports the magnetizer 2, and a spring having casters 4. A moving carriage 5 for supporting the magnetizer 2 via 3,
Have. The magnetizer 2 has a structure in which a coil is wound around the lower iron core 2b of the U-shaped iron core 2a, and a gap of 2-3 mm is generated between the magnetizer 2 and the surface 1a when the power is off. When power is supplied, the magnetic force causes the iron core 2a to be attracted to the surface 1a and adhere to it. [Effect] By closely contacting the magnetic pole and the object to be inspected during the inspection, it is possible to prevent a decrease in the magnetic flux density and improve the inspection capability by expanding the inspection range.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an inter-electrode magnetic flaw detection device used for nondestructive inspection of magnetic materials such as welded steel structures.

[0002]

[Prior art]

 An inter-pole magnetic flaw detector for magnetic particle flaw detection is designed so that the magnetic poles of the equipment are opposed to each other across the portion to be inspected such as the welded part of the steel structure, and the portion to be inspected is magnetized and liquid It is intended to inspect the presence or absence of defects in the structure from the accumulated magnetic powder by spraying the magnetic powder. Such an inter-electrode magnetic flaw detector is stopped at the inspection position for inspection, and when the inspection is completed, it is moved to the next inspection position and used by repeatedly moving and stopping, so it is easy to move / stop. It is structured. Therefore, conventionally, a fixed caster was attached to the tip of the magnetic pole as a moving mechanism.

However, in such a conventional moving mechanism, the caster needs to protrude to some extent from the tip of the magnetic pole in order to make it movable, and the surface of the object to be inspected may not be a flat surface. Therefore, a gap of 2 mm or more is usually provided between the magnetic pole and the surface of the object to be inspected. As a result, the magnetic flux density entering the inspected part of the material was significantly reduced. For example, if the gap between the magnetic pole and the test body is 2 mm, the magnetic flux density will be 20% or less as compared with the case where both are closely attached. As a result, there was a problem that the inspection ability of the device in the inspectable range decreased and the inspection efficiency was poor. On the other hand, if the capacity of the magnetic pole is increased in consideration of such a decrease in the magnetic flux density, the price of the device will be greatly increased, and the overall weight will be heavy, resulting in poor operability.

[0004]

[Problems to be solved by the device]

 SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems in the prior art and to provide an inter-electrode magnetic flaw detector with good magnetic flux density and good inspection efficiency.

[0005]

[Means for Solving the Problems]

 SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an inter-electrode magnetic flaw detector, which has at least a pair of magnetic poles composed of an N pole and an S pole that magnetize an object to be inspected when energized, and an expansion / contraction supporting the magnetic pole. It has a flexible elastic member and a rotating body that rolls on the surface of the object to be inspected, and a structure that supports the magnetic poles via the elastic member with a gap from the surface of the object to be inspected when energization is stopped. However, the gap is a gap in which the magnetic pole is attracted to the object to be inspected during energization.

[0006]

[Work]

 According to the present invention, since the magnetic pole is supported by the expansion / contraction member, the magnetic pole is movable in the expansion / contraction direction. When the energization is stopped, the magnetic pole is supported by the structure with a gap between the magnetic pole and the object to be inspected through the expansion and contraction member, and the structure has a rotating body that rolls on the surface of the object to be inspected. Are easily moved on the object to be inspected. On the other hand, the magnetic poles become magnets when energized, magnetize the inspection object, and generate magnetic attraction between the magnetic poles and the inspection object. When energized, the gap between the magnetic pole and the object to be inspected is such that the magnetic pole can be attracted to the object to be inspected. Therefore, when the current is applied to perform magnetic flaw detection on the object to be inspected, the magnetic pole and the object to be inspected inevitably. Magnetically adheres by magnetic force. As a result, the object to be inspected is magnetized without decreasing the magnetic flux density. That is, according to the present invention, both easy movement and high magnetic flux density at the time of inspection are satisfied, and the inspection efficiency is improved.

[0007]

【Example】

 1, FIG. 2 and FIG. 3 show the structure of the inter-electrode magnetic flaw detector of the embodiment, and are a front view, a plan view and a side view, respectively. The present inter-pole magnetic flaw detection apparatus has at least a pair of N poles composed of an N pole and an S pole, which magnetize the inspection object, for example, the welding structure 1 when energized.₁ , N ₂ , S₁ , S₂ A quadrupole magnetizer 2 consisting of, a spring 3 which is an example of an expandable and contractible member for supporting the magnetizer 2, and a caster 4 as a rotating body rolling on the surface 1a of the welded structure 1 are turned off. The movable carriage 5 as a structure for supporting the magnetizer 2 via the spring 3 with a gap δ from the surface 1a.

In this embodiment, the magnetizer 2 has a structure in which four iron cores 2b are hung below a U-shaped iron core 2a and a coil is wound around the iron cores 2b, N ₁ , N ₂ , It is composed of four poles S ₁ and S ₂ . The iron core 2b has a cross-sectional size of 25 mm × 25 mm, and its gap is 140 mm between NS and 100 mm between N and N. Then, by inputting an AC power supply to the magnetizer 2, it is possible to reliably inspect the range of an ellipse having a major axis of 100 mm and a minor axis of 65 mm.

The spring 3 is provided in a bolt 7 suspended from a moving carriage 5 via a flange 6, and the lower end side thereof is supported by a nut 8 and the upper end side thereof supports the iron core 2 a. The magnetizer 2 is elastically supported by the moving carriage 5 by being pressed against the protruding portion 9a of the member 9. There are three support points. Then, in a state where no power is supplied to the magnetizer 2, there is a gap δ between the tip of the iron core 2b and the surface 1a of the welded structure 1. This gap δ may have a size that allows the magnetizer 2 to move without hitting the welded structure 1 or the like even when the surface of the welded structure 1 or the like to be inspected is not a locally flat surface. It is 3 mm. If the gap is in this range, the magnetizer 2 becomes an electromagnet when power is supplied to the magnetizer 2, and the magnetic force generated between the magnetizer 2 and the weld structure 1 causes the iron core 2b to move to the weld structure 1. It can be adsorbed on the surface 1a of the above and made to adhere.

A main part of the movable carriage 5 is composed of a base plate 5a and a pillar 5b, and a caster 4 is attached to a lower end of the pillar 5b. The caster 4 is a free caster that rotates 360 °. A handle 10 is attached to the movable carriage 5. With such a structure, the moving carriage 5 can move in any direction when the power supply is stopped. As a result, the apparatus can be moved easily as compared with the conventional fixed caster, and in this respect also, the inspection efficiency is improved as compared with the conventional one. The movable carriage 5 is further provided with a magnetizing power relay box 11. Then, the magnetizing power supply can be turned on / off by the switch 11a attached thereto.

Due to such a structure, the present inter-pole magnetic flaw detector is used as follows. For example, the apparatus is set so that the inspection target portion of the inspection object such as the welded portion of the welded structure 1 is crossed by the N pole and the S pole, and the magnetizing power relay box 11 is turned on to turn on the magnetizer 2. A test liquid composed of wet fluorescent magnetic powder is sprayed on the test target portion while electricity is supplied. By this energization, the magnetizer 2 is brought into close contact with the welded structure 1 with a magnetic force, and magnetizes the welded structure 1 in a constant area range from the surface and surface of the welded structure 1 to a predetermined depth. As a result, if there is any defect in the inspection target range of the welded structure 1, the magnetic field lines are cut off at the defective portion, the magnetic flux leaks, and the magnetic particles move and gather at the defective portion. To be detected. In this embodiment, the combination of magnetic poles is N₁ -S₁ And N ₂ -S₂ Since the power supplied to them is sequentially switched, all defects in the 360 ° direction can be detected.

In this case, since the magnetizer 2 is in close contact with the welded structure 1, the magnetic flux density entering the welded structure 1 does not decrease, so the inspection accuracy is improved and the inspection range is widened. be able to. For example, in the conventional apparatus in which casters are attached to the magnetic poles and a gap of about 2 mm is provided between the magnetic pole and the inspection surface, the limit of the inspectable range with the power supply of 220 V AC is 60 mm × 60 mm, whereas in the apparatus of the embodiment, It has been confirmed by experiments that the inspectable range is 100 mm × 65 mm or more even when the power supply voltage is 160 V with the same magnetic pole size.

Next, when the inspection within a certain range is completed, the power supply to the magnetizer 2 is turned off. As a result, the magnetic force between the magnetizer 2 and the welded structure 1 disappears, and the magnetizer 2 is pulled up from the surface 1a of the welded structure 1 by the elastic force of the spring 3 and separated between A gap of 3 mm is created. This gap allows the device to be easily moved while holding the handle 10. Then, when the apparatus is moved to the next inspection area, it is stopped there, the power is turned on again, the magnetizer 2 is brought into close contact with the welded structure 1, and the inspection is performed in the same manner. By repeating such inspection / movement, the magnetic particle inspection of the entire range of the inspection object is performed.

According to the above-described inspection method, the welded structure 1 and the magnetizer 2 are in close contact with each other, so that the inspection range is widened, and there is a sufficient gap during the movement to facilitate the movement. Therefore, the inspection efficiency is significantly improved. In the past, two inspectors performed a group of inspections, but the apparatus of this embodiment allows one person to perform an inspection.

Although a case has been described above where a person operates / moves the inter-electrode magnetic flaw detector, the present invention can also be applied to a case where the operation or movement of the device is automated.

[0016]

[Effect of device]

 As described above, according to the present invention, it is possible to prevent a decrease in magnetic flux density and improve the inspection capability by expanding the inspection range. In particular, in a device in which the magnetizer is powerful and has multiple poles and is large in size, it has a great effect on reducing the overall weight and the cost of the device and inspection.

[Brief description of drawings]

FIG. 1 is a front view of an inter-electrode magnetic flaw detector according to an embodiment.

FIG. 2 is a plan view of the device.

FIG. 3 is a side view of the device.

[Explanation of symbols]

 2 Magnetizer (magnetic pole) 3 Spring (expandable member) 4 Casters (rotating body) 5 Moving carriage (structure)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takaman Kishimine 1 Kawasaki-cho, Sakaide-shi, Kagawa Kawashige Inspection Service Co., Ltd. Sakaide Works (72) Inventor Shigenobu Miyakawa 1-side, Kawasaki-cho, Sakaide, Kagawa Prefecture Kawaju-inspection Service Sakaide Office

Claims (1)

[Scope of utility model registration request] 1. At least a pair of magnetic poles composed of an N pole and an S pole that magnetize an object to be inspected by being energized, an expandable elastic member supporting the magnetic pole, and rolling on the surface of the object to be inspected. And a structure for supporting the magnetic poles via the elastic member with a gap from the surface of the object to be inspected when the energization is stopped. An inter-electrode magnetic flaw detector characterized in that it is a gap to be attracted.