JPH05203628A - Magnetic particle inspection device for rectangular steel product and conveyor device for magnetic particle inspection of rectangular steel product - Google Patents

Abstract

PURPOSE:To provide a magnetic particle inspection device and a conveyor device for magnetic particle inspection with which deterioration of detection sensitivity for surface defects of an angular part of an angular steel material can be prevented, and with which they can be detected continuously with surface defects of the whole body of the steel material. CONSTITUTION:A conveyor device for magnetic particle inspection for angular steel materials comprises a coil magnetizer 5 comprising a rotary magnetizing coil for giving a magnetic field which rotates about an axis almost in the same direction as that of an axial center of the angular steel material, and a DC magnetizing coil wound to surround an outer circumferential surface of the angular material, and an interpole magnetizer 6 for magnetizing the angular material between magnetic poles provided continuously along the length of the angular steel material. It also comprises conveyor chains 8 having intermittently provided support plates 10 having V-letter cuts for installing angles of the angular steel material with the surfaces of the angular steel material inclined, and plural drive wheels for driving the conveyor chains 8, and the conveyor chains 8 let either or both of the coil magnetizer 5 and the interpole magnetizer 6 pass.

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 used for detecting surface defects of square steel having a square cross section.

[0002]

2. Description of the Related Art Eddy current flaw detection, dye penetration flaw detection, and magnetic particle flaw detection (also simply referred to as magnetic flaw detection) are known as methods for detecting surface defects in metal materials such as steel. Among them, the magnetic particle flaw detection method detects a defect by utilizing a phenomenon in which a magnetic flux leaks to a surface defect portion of a material to be inspected when the surface of the material to be inspected such as a steel material is magnetized and magnetic powder adheres to this portion. . Usually, a fluorescent agent or the like is mixed with this magnetic powder so that the defects can be visually confirmed. This magnetic particle flaw detection method is a method of detecting surface defects, which has extremely high detection sensitivity, because the surface defects are emphasized by the leakage magnetic flux. In such a magnetic particle flaw detection method, various means are used to magnetize the surface of the material to be inspected. For example, there are a direct energization method in which a current is directly applied to the material to be inspected to magnetize it, an inter-electrode magnetization method in which the material to be inspected is introduced and magnetized between the magnetic poles, and a coil magnetization method in which the material is magnetized by a coil.

Of these, in the direct energization method and the pole-to-pole magnetization method, since there is a single magnetic field, the leakage magnetic flux that attaches the magnetic particles is generated in the defect portion in the direction perpendicular to the magnetization direction of the material to be inspected, and in the parallel direction. Since the defect hardly occurs in the defective portion, there is a problem that the detected defect is limited to only one direction. Further, the direct energization method has a problem that the surface of the material to be inspected may be damaged due to the generation of sparks on the contact surface for energization. On the other hand, the coil magnetizing method generates a composite magnetic field by combining a plurality of magnetizing coils and exciting the magnetizing coils with a plurality of AC or DC power supplies as shown in, for example, Japanese Utility Model Laid-Open No. 2-50678. By providing a rotating magnetic field, it is possible to detect all surface defects regardless of the direction of defects on the surface of the material to be inspected.

[0004]

However, even in such a coil magnetization method, surface defects of a steel material having a polygonal cross section represented by a steel material having a quadrangular cross section, that is, a steel material having a square cross section, When trying to detect, the defect detection sensitivity differs depending on the position of the defect on the surface of the steel material, and in particular, the problem that the detection sensitivity of the surface defect at the corner is poor occurs. In particular, for a steel material obtained by rolling, cracks are likely to occur because tensile stress is applied to the corners, and the decrease in the detection sensitivity of surface defects at the corners poses a problem. The present invention is
A device for detecting a surface defect of a square steel material having a square cross section, particularly a magnetic particle flaw detection device and a corner used for the magnetic particle flaw detection device capable of detecting the surface defect of the entire steel material while preventing a decrease in the detection sensitivity of the corner portion. An object of the present invention is to provide a carrier for magnetic particle flaw detection of a shaped steel material.

The present inventors have found that the decrease in the detection sensitivity of the corner portion of the square steel material by the coil magnetizer is due to the decrease in the magnetic flux density across the surface defect of the corner portion. It has been found that the reduction of the magnetic flux density across the surface defects at the corners can be compensated by providing the vessel continuously in the longitudinal direction of the square steel material. That is, the present invention relates to a rotating magnetizing coil that gives a magnetic field that rotates around an axis in substantially the same direction as the axis of a square steel material having a square cross section, and a DC magnetizing coil wound so as to surround the outer peripheral surface of the square material. A magnetic particle flaw detector for a square steel material, comprising a coil magnetizer provided with and an interelectrode magnetizer that magnetizes a square material between magnetic poles. Moreover, it is preferable that the magnetic particle flaw detector for the square steel material has a transporting device that allows the square steel material to pass through the coil magnetizer and the gap magnetizer while holding the square steel material in an inclined posture.

[0006]

The operation of the present invention will be described with reference to the drawings of one embodiment of the present invention. The greatest feature of the present invention is that the coil magnetizer and the inter-electrode magnetizer are continuously provided in the longitudinal direction of the square steel material. As described above, the coil magnetizer alone is not suitable for inspecting the entire circumference of a square steel material because the sensitivity of detecting the corner portion of the square steel material is low. In addition, as shown in FIG.
The generated magnetic flux 4 tends to be concentrated and converged on the corners of the inspected material 1, and has the effect of increasing the magnetic flux density at the corners of the inspected material. However, as described above, there is a problem that only surface defects in a single direction can be detected. According to the present invention, the coil magnetizer and the inter-electrode magnetizer are continuously provided in the longitudinal direction of the square steel material, so that the surface defect of the corner portion, for which sufficient detection sensitivity cannot be obtained only by the coil magnetizer, depends on the defect direction. It is possible to detect the defects continuously, and to obtain sufficient defect detection sensitivity even on the surface other than the corners. It is unclear how the magnetic field generated by the coil magnetizer and the pole magnetizer affects the magnetic field generated on the surface of the square steel material, but the coil magnetizer alone was insufficient. It can be inferred that the magnetic flux density at the corners was supplemented by the interpolar magnetizer. The coil magnetizer of the present invention has the coil arrangement shown in FIG. 5 as an example.

Coils indicated by AA and BB in FIG. 5 are rotating magnetic field coils for giving a rotating magnetic field, and they are arranged at right angles to each other, for example, two phases of three-phase alternating current are energized. By doing so, an elliptical rotating magnetic field can be generated. The coil indicated by C-C is a DC magnetizing coil, and a magnetic field parallel to the axis of the material 1 to be inspected can be obtained. In the vector 2 of the magnetic field generated by these three coils, the locus of the tip of the vector draws an ellipse shown in FIG. 6, and it becomes possible to detect a defect that does not depend on the directionality of the defect.

The combination of the magnetic field generated by the coil magnetizer shown in FIG. 6 and the magnetic field generated by the pole magnetizer shown in FIG. It is possible to detect defects on the entire circumference of the surface of steel materials having various shapes. Further, in the present invention, a carrier containing a coil magnetizer and an interelectrode magnetizer while installing the square steel material in an inclined posture is installed to prevent the solution containing magnetic powder from staying on the surface of the square steel material. As a result, the magnetic powder can be uniformly and stably dispersed, so that the fixing can be performed with high accuracy. This transport device will be described in detail. A transport chain in which a support plate having a V-shaped notch for inclining the surface of the square steel material to set the corner of the square steel material is intermittently provided, and the transport chain is driven. And a plurality of drive wheels, and the transport chain has a structure that passes through either or both of the coil magnetizer and the pole magnetizer. By installing the square steel material in the transport chain in which the support plate having the V-shaped notches is intermittently provided, the square steel material can be continuously transported while being held in an inclined posture, and the solution containing the magnetic powder is square. It is possible to prevent the mold steel material from staying on the surface.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of the configuration of a magnetic particle flaw detector according to the present invention. In FIG. 1, a square steel material to be inspected 1 is conveyed in an arrow direction in the drawing by an endless conveying chain 8 driven by a driving wheel 7, and passes through a coil magnetizer 5 and a gap magnetizer 6. . At this time, the magnetic powder is supplied to the material 1 to be inspected from the magnetic powder supply port 9 in front of the coil magnetizer 5 in the conveying direction, and the magnetic powder is fixed to the surface defect portion while passing through the coil magnetizer 5 and the inter-electrode magnetizer 6. By observing the material to be inspected after passing through the gap magnetizer 6, the presence or absence of surface defects can be continuously confirmed. As shown in FIG. 2, support plates 10 having V-shaped notches serving as supporting portions of the material 1 to be inspected are installed in the transport chain 8 at equal intervals. It has a structure that can be set in the notch and transported in an inclined posture.

The coil magnetizer 5 shown in FIG. 1 is shown in FIG.
FIG. 2 is a view showing the coil magnetizer 5 as viewed from the conveyance direction of the material to be inspected. The coil magnetizer shown in FIG. 2 is A- shown in FIG.
A rotating magnetic field coil for giving a rotating magnetic field shown by A and BB, and C
It is composed of a coil portion 11 composed of a DC magnetizing coil shown by -C, an insulating plate 12 supporting the coil portion 11, a support base 13 on which these are mounted, and a linear guide 14. Here, the horizontal position of the coil portion 11 can be adjusted by the handle 15 connected to the support base 13 so that the inspected material 1 comes to the center position. Further, the transport chain 8 having the support plate 10 on which the inspected material 1 rides is provided so as to penetrate the coil portion 11.

FIG. 3 shows the interpolar magnetizer 6 shown in FIG. FIG. 3 is a diagram showing the inter-pole magnetizer 5 viewed from the transport direction of the material to be inspected. The inter-pole magnetizer 6 shown in FIG. 3 serves as a magnetic pole distance adjusting handle 16 for adjusting the distance between the magnetic poles 3 installed above and below, a magnetic path of the upper and lower magnetic poles 3, and an exciting coil 17 is wound around it. U-shaped arm 18 and insulating plate 12 that supports arm 18 and support 13 on which these are mounted
And a linear guide 14. Here, the magnetic pole 3 is installed so as to be movable on the linear guide 14 in parallel with the facing plane of the material to be inspected, and can be adjusted to the center of the material to be inspected 1 by the handle 15. Using the magnetic particle flaw detector of FIG. 1, JIS-2504 A-1 test piece 15/50
When surface defects were detected by, it was possible to detect surface defects on the entire circumference continuously at a conveying speed of 15 m / min.

[0012]

According to the present invention, the problem that the detection sensitivity of the surface defects at the corners of a square steel material having a special shape of square shape is poor with only the coil magnetizer is a problem. Since it was solved by arranging continuously, it became possible to accurately and continuously detect the magnetic powder on the entire circumference of the square steel material. As a result, it is possible to provide an extremely useful apparatus for quality control of a square steel product, which is particularly concerned with the occurrence of defects in the corners and which requires highly accurate detection of surface defects.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the configuration of a magnetic particle flaw detector according to the present invention.

FIG. 2 is a diagram showing an example of the configuration of a coil magnetizer that is a main component of the magnetic particle flaw detector of the present invention.

FIG. 3 is a diagram showing an example of a configuration of an inter-pole magnetizer which is a main component of the magnetic particle flaw detector of the present invention.

FIG. 4 is an explanatory diagram showing a relationship between magnetic poles and magnetic flux of an inter-electrode magnetizer.

FIG. 5 is a diagram showing an example of arrangement of coils of a coil magnetizer.

6 is a diagram showing a vector of a magnetic field generated by the coil magnetizer shown in FIG.

[Explanation of symbols]

 1 Inspected Material 3 Magnetic Pole 5 Coil Magnetizer 6 Inter-pole Magnetizer 7 Drive Wheel 8 Transport Chain 9 Magnetic Powder Supply Port 10 Support Plate 11 Coil Part 13 Support Stand 14 Linear Guide 17 Excitation Coil 18 Arm

Continuation of the front page (72) Inventor Mitsuo Numaguchi 1-2-13 Higashishimbashi, Minato-ku, Tokyo Sakae Evolution Gaku Co., Ltd.

Claims (3)

[Claims] 1. A rotating magnetizing coil that gives a magnetic field that rotates around an axis substantially in the same direction as the axis of a square steel material having a square cross section, and a DC magnetizing coil wound around the outer peripheral surface of the square material. A magnetic powder flaw detector for a square steel material, comprising a coil magnetizer provided with and an interelectrode magnetizer that magnetizes a square material between magnetic poles in a continuous manner in the longitudinal direction of the square steel material. 2. The magnetic particle flaw detector for a square steel product according to claim 1, further comprising a conveying device for passing the coil magnetizer and the gap magnetizer while holding the square steel product in an inclined posture. 3. A carrying chain intermittently provided with a supporting plate having a V-shaped notch for inclining the surface of the rectangular steel material to set the corners of the rectangular steel material, and a plurality of driving chains for driving the carrying chain. And a drive wheel of the above, and the transport chain has a structure that passes through either or both of a coil magnetizer and a pole magnetizer.