JPH0592712U - Magnetizing device for magnetic particle inspection of rolling rolls - Google Patents

Abstract

(57) [Abstract] [Purpose] A magnetic flux can be effectively applied to the surface of a steel rolling roll to be flaw-detected in a non-contact state, and magnetic particle flaw detection can be continuously performed while rotating the roll. A magnetizing device for magnetic particle flaw detection of a rolling roll is provided. [Structure] Leg iron cores 12, 13, 14, of a rotating magnetic field pole magnetizer 1 having four leg iron cores 12, 13, 14, 15 hanging from an H or X-shaped upper iron core 11. Each lower end surface of 15 is an inward slope, and the magnetizer 1 is attached to the pedestal 2 in a vertically and horizontally movable state, and the steel rolling roll A is rotatable in front of the gantry 2. A carriage 3 that supports and can move back and forth is provided.

Description

[Detailed description of the device] [Industrial applications]

 The present invention relates to a magnetizing device for magnetic powder flaw detection of a rolling roll, and provides a magnetizing device capable of accurately and efficiently detecting magnetic powder flaws of a steel rolling roll.

As is well known, a non-destructive inspection is carried out at a manufacturing site for steel rolling rolls, particularly for steel sleeve rolls having a caliber, in order to prevent cracking due to cracks and the like. Currently, there are three types of flaw detection methods used for nondestructive inspection of steel sleeve rolls having a caliber: ultrasonic flaw detection method, eddy current flaw detection method, and penetrant flaw detection method. On the other hand, for non-destructive inspection, in addition to the above-mentioned three types of flaw detection methods, there is a magnetic particle flaw detection method standardized in “JIS G0565-1 974”. To the inventor's knowledge, this magnetic particle flaw detection method is used. Not used for steel mill rolls. Further, in carrying out the magnetic particle flaw detection method, it is indispensable to magnetize the flaw detection target. As seen in "Published on April 28, 1978, first edition," various magnetizing methods and devices are in practical use.

[0002]

[Problems to be solved by the device]

 As described above, the above-mentioned three types of flaw detection methods are adopted for nondestructive inspection of steel rolling rolls, but the following problems are inherent. That is, in the ultrasonic flaw detection method, since the surface wave is used, the surface roughness of the inspection surface of the rolling roll becomes noise, and the flaw may not be detected when the flaw is parallel to the traveling direction of the sound wave. In the eddy current flaw detection method, it is difficult to discriminate between scratches, unevenness, unevenness in hardness, etc., and often grinding is not necessary. In the penetrant flaw detection method, it takes time and effort to remove the applied developer (white inorganic fine powder).

When the object to be inspected is a sleeve sleeve made of steel having a caliber, in the ultrasonic flaw detection method and the eddy current flaw detection method, a probe and a probe suitable for the shape and size of the caliber are prepared. However, in the penetrant flaw detection method, it takes a lot of time to remove the developer adhering to the bottom of the caliber.

On the other hand, the magnetic particle flaw detection method is widely used in the manufacturing site of steel materials such as square billets and round billets, and it is well known that the flaw detection accuracy and work efficiency are excellent, but As it is, it is not adopted for steel rolling rolls. This is because when magnetism detection is applied to steel materials such as square billets and round billets (usually square billets are 110 to 160 mm square and round billets are 110 to 160 mmφ), the magnetization is directly applied in the axial direction of the steel material. Combined use of the "axis-current magnetizing method" of passing an electric current and the "coil magnetizing method" of inserting steel material into the coil (used to detect flaws that are present at right angles to the axial direction and flaws that are present in parallel with each other. However, the current directly applied to the steel material is relatively small (usually 5000 to 6000A), but steel rolling rolls are usually 300 to 500mmφ, so In order to magnetize by applying the "electromagnetization method", a large current of 10000 to 2000 0 A needs to be directly passed, and when the current becomes large, the power source and various equipment must be enlarged. Risk of sparks and damage to the roll surface when a large current is applied directly Because there is.

The inventor of the present invention considers that the problems described above can be solved by adopting the magnetic particle flaw detection method for a steel rolling roll, particularly a steel sleeve roll having a caliber, and studied the magnetization method / apparatus thereof. Focusing on the "pole-to-pole magnetizing method" in which the flaw detection part of the flaw detection object is placed between the two poles of the electromagnet and magnetized, the magnetizer is equipped with four well-known leg iron cores. If a magnetizer (see Japanese Utility Model Publication No. 56-99808, Japanese Utility Model Publication No. 58-148660 and Japanese Utility Model Publication No. 59-176954) is used, a flaw existing parallel to the axial direction is present. In view of the fact that and can be detected at the same time, we have started the research aiming at its practical application.

Then, the present inventor, when the steel rolling roll is magnetized in a non-contact state by a conventional rotating magnetic field pole magnetizer having four leg iron cores, I learned that there is a big problem that sufficient detection accuracy cannot be obtained because the magnetic flux cannot be injected effectively. Therefore, the inventor of the present invention has made it a technical task to provide a magnetizing device for magnetic particle flaw detection that can effectively apply a magnetic flux to the inspection surface of a steel rolling roll in a non-contact manner.・ As a result of repeated trial production, we have completed technical means to solve the above problems and achieved the problem.

[0007]

[Means for Solving the Problems]

 The above technical problems can be achieved by the present invention as follows. That is, the present invention provides four leg iron cores having the same length that hang down from each tip of the H or X-shaped upper iron core and an exciting coil wound around the four iron cores. The lower end face of each leg iron core of the provided rotating magnetic field pole magnetizer is an inward slope, and this rotating magnetic field pole magnetizer is mounted on the magnetizer mount so that it can move vertically and horizontally. In front of the gantry, a rolling-roll-equipped carriage that supports the rolling roll to be inspected in a rotatable state and can move back and forth is installed, and the inspection surface of the rolling roll mounted on the trolley is mounted. Is a magnetizing device for magnetic particle flaw detection of a rolling roll, which is magnetized immediately below the lower end surface of each leg iron core of the rotating magnetic field pole magnetizer.

Next, the configuration of the present invention will be described in more detail with reference to the drawings. A specific embodiment of the magnetizing device for magnetic particle flaw detection of a rolling roll according to the present invention is as shown in a side view of FIG. 1, a front view of FIG. 2 and a perspective explanatory view of FIG.

First, the rotating magnetic field pole magnetizer 1 is mounted on the magnetizer mounting base 2 with the leg iron cores 12, 13, 14 and 15 facing downward so as to be vertically and horizontally movable. There is.

That is, the pedestal 2 is composed of two columns 21 and 22 and a cross girder 23 which is fixed between the columns 21 and 22, and is vertically moved between the columns 21 and 22. A horizontal bar 24 is slidably attached to the columns 21 and 22 at both ends thereof, and a plate member 25 that moves left and right is slidably attached to the horizontal bar 24 at its upper surface portion. The rotating magnetic field pole magnetizer 1 is fixed to the lower surface of the plate 25. Therefore, the rotating magnetic field pole magnetizer 1 moves vertically and horizontally by the sliding along the columns 21 and 22 of the horizontal bar 24 and the sliding along the horizontal bar 24 of the plate 25.

When the horizontal bar 24 and the plate 25 are slidably attached, a well-known chain mechanism, rail mechanism, or the like may be appropriately selected and used, and the horizontal bar 24 and the plate 25 may be used. For sliding, the electric drive method using a motor and a gear mechanism may be adopted according to a conventional method, and a manual drive method using a handle and a gear mechanism may be adopted.

Next, in front of the magnetizer mount 2 on which the rotating magnetic field pole magnetizer 1 is mounted, a steel rolling roll A to be flaw-detected is rotatably supported and movable back and forth. A rolling roll-carrying carriage 3 is installed.

That is, the trolley 3 is composed of a base 31 and two sets of wheels 32 and 33 attached to the back surface of the base 31, and a frame 34 is fixed to the surface of the base 31 and Two sets of rotating roller mechanisms 35 and 36 are mounted on the upper surface of 34 at intervals. The rolling roll-mounted cart 3 is guided forward (in the direction of the arrow in FIG. 1) by a rail 4. The steel rolling roll A, which is the object of flaw detection, is placed on and supported by the rotating roller mechanisms 35 and 36 in parallel with the horizontal bar of the gantry 2. Therefore, when the carriage 3 moves forward, the steel rolling roll A mounted on the carriage moves below the rotating magnetic field pole magnetizer 1.

The rotary roller mechanisms 35 and 36 are well-known mechanisms, each of which is composed of two rollers that face each other and are rotatably supported by a shaft, and are rotated by a chain mechanism or a belt mechanism. Then, the steel rolling roller A which is being supported is rotated. If nylon rollers are used for the rollers of the rotating roller mechanisms 35 and 36, the surface of the steel rolling roller A is not damaged. Further, the rotating roller mechanism is driven by an electric drive system using a motor and a gear mechanism or by a manual drive system using a handle and a gear mechanism according to a conventional method.

As shown in FIG. 3, the rotating magnetic field pole magnetizer 1 has four leg iron cores 12, 13 having an equal length depending from each tip of the H-shaped upper iron core 11. , 14 and 15 and the exciting coils 16, 17, 18 and 19 wound around the respective leg iron cores, and the lower end faces of the four leg iron cores 12, 13, 14 and 15 are respectively placed inside. It is a slope with an inclination angle of 25 ° (see below, see Fig. 5). In addition, the rotating magnetic field pole magnetizer 1 has a new configuration in that the lower end surface of each leg iron core is an inward slope, and other than this point, as seen in the above-mentioned respective publications, the circumference is the same. It is knowledge.

A specific mode of magnetizing the surface of the steel rolling roll A to be a flaw detection target by using the magnetizing device for magnetic particle flaw detection of a rolling roll as described above is as follows. After the steel rolling roll A is placed on and supported by the rotating roller mechanisms 35, 36 of the rolling roll-carrying carriage 3, the carriage 3 is moved forward so that the roll A is located below the rotating magnetic field pole magnetizer 1. Position it. Next, with the magnetizer 1 energized to excite the iron core, the lower end surfaces of the legs of the iron cores 12, 13, 14 and 15 are located at positions closest to the surface (peripheral surface) of the roll A. When the magnetizer 1 is lowered to this position and stopped at this position, the rolling magnetic field generated from the leg iron cores 12, 13, 14 and 15 causes the roll A in a non-contact state with each lower end face of the leg iron cores. Surface is magnetized. At this time, the magnetized portion of the roll A surface becomes the inspection portion.

By performing a magnetic particle flaw detection method on the above-mentioned inspection portion using a fluorescent magnetic powder and a black light (ultraviolet lamp) in accordance with a conventional method, it is possible to detect whether or not there is a defect such as a crack at the inspection portion. When the magnetizer 1 is stopped at the above position, magnetic powder flaw detection is performed on the magnetized portion (inspection portion) while the roll A is rotated by the rotating roller mechanisms 35 and 36. The points facing the cores 12, 13, 14 and 15 can be continuously flaw-detected over the entire circumference. Then, move the magnetizer 1 from the above position to the right or left for the required distance, magnetize the surface of the roll A and perform the magnetic particle flaw detection method in the same manner as above. It is possible to detect flaws continuously.

Further, in using the magnetizing device for magnetic particle flaw detection of the rolling roll as described above, the leg iron cores 12, 13 of the rotating magnetic field pole magnetizer 1 are adopted by adopting the following spacing control means. , 14 and 15 can be controlled so that the distance between each lower end surface and the surface of the steel rolling roll A to be flaw-detected is always constant.

That is, one of the exciting coils 16, 17, 18 and 19 of the rotating magnetic field pole magnetizer 1 is provided with an output terminal 5 for detecting an impedance change of the coil, and the output terminal 5 is 4, the comparator 6 is connected, the comparator 6 is connected to the calculator 7, and the calculator 7 is connected to the controller 8. Then, the current (i) from the output terminal 5 to the comparator 6, the current target set interval value between the lower end surface and roles A surface of the leg iron core 12, 13, 14 and 15 (i _o) Is input, and the difference ( _io −i) is calculated by the calculator 7, and the current (i) and the current ( _io ) are always matched from the controller 8 according to the calculation result input from the calculator 7. The control signal necessary for this is output, and the vertical position of the magnetizer 1 is constantly adjusted by the control signal.

It is to be noted that the comparator 6, the arithmetic unit 7, and the controller 8 can be any known ones, and their circuits may be formed according to a conventional method. In addition, the control signal output from the controller 8 can be used to control the plate 25 when it is slid by an electric drive system, and the plate 25 is slid by a manual drive system. If so, it can control lamps and buzzers to attract the attention of workers.

[0021]

[Action]

 In the present invention, the most important action is that the lower end faces of the iron cores of the legs of the rotating magnetic field pole magnetizer are inclined inward. That is, FIG. 5 is a model diagram showing the positional relationship between the shape of the lower end surfaces of the iron cores 12 and 13 of the rotating magnetic field pole magnetizer and the surface (peripheral surface) of the steel rolling roll A as the flaw detection target. FIG. 3 is a partially omitted side view illustrated in FIG. If the lower end surface of the leg iron core is flat (there is no shaded area in the figure), the distance from the surface of roll A is large and the magnetic resistance is large. The amount of magnetic flux input to the surface decreases, and the gap between the lower end surface of the leg iron core and the surface of the roll A is large, so that the defect detection accuracy is low. On the other hand, in the present invention, since the lower end surfaces of the leg iron cores are inclined inward (there are the shaded portions in the figure), the distance of the shaded portions can approach the surface of the roll A, so that the magnetic The resistance can be reduced. Therefore, the amount of the magnetic flux injected into the surface of the roll A becomes large, and the gap between the lower end surface of the leg iron core and the surface of the roll A becomes almost constant, so that the defect detection accuracy can be improved. Is improved.

That is, in the present invention, the lower end surfaces of the leg iron cores are made as slopes facing inward to approach the surface of the roll A as much as possible to effectively introduce the magnetic flux. Sufficient magnetization can be performed to guarantee the accuracy of magnetic particle flaw detection in the non-contact state.

In addition, it is theoretically desirable to make each of the lower end surfaces of the leg iron cores an inwardly directed slope into an arcuate slope, but it is desirable to cut the slope in a straight line into a slope. Even if it is formed, it can be practically used. As shown in the figure, it is preferable to make an angle of inclination of about 25 ° when cutting, and this is because the diameter of the steel rolling roll is usually 300 to 500 mmφ and an angle of inclination of about 25 °. This is because it is possible to deal with these.

Next, the operation of the present invention will be described when the interval control means is adopted. When the rotating magnetic field pole magnetizer 1 descends and the exciting coils 16, 17, 18 and 19 approach the steel rolling roll A that is the flaw detection target, an eddy current is generated on the surface of the roll A and is generated by this. The generated magnetic flux effectively reduces the impedance of the exciting coil. Therefore, the coil current (i) increases when the distance between the exciting coil and the surface of the roll A decreases, and conversely, the coil current (i) decreases when the distance increases. Using this relationship, the exciting coil current (i ₀ ) and the coil current (i) when the lower end surfaces of the leg iron cores 12, 13, 14 and 15 and the surface of the roll A are set to the target intervals The interval can be controlled by comparing and calculating.

[0025]

【Example】

Using a magnetizing device for magnetic particle flaw detection of a rolling roll according to the present invention shown in FIGS. 1, 2 and 3, a steel rolling roll was magnetized under the following conditions, and a magnetic particle flaw detection method was performed according to a conventional method. (1) Magnetization conditions Steel rolling roll A: Steel sleeve roll with caliber: Roll diameter 440 to 337.5 mm, sleeve width 250 to 175 mm, caliber width 60.8 to 19.7 mm. Rotating magnetic field pole magnetizer 1: 200 VAC power supply, vertical movement distance of about 200 mm, left and right movement distance of about 800 mm. The distance between the lower end surfaces of the leg iron cores 12, 13, 14 and 15 and the surface of the roll A when magnetized: 5 mm ± 1 mm. Central magnetic field on the surface of the roll A during magnetization: about 60 Oe or more (measured by an AC magnetic field magnetometer TAM-1). Rotational peripheral velocity of the roll A during magnetization: about 1 m / min. (2) Magnetic powder flaw detection conditions Magnetic powder liquid used: Fluorescent magnetic powder LY2500 (trade name: manufactured by Mark Tech Co., Ltd.) was dispersed at a rate of 0.5 g per 1 liter of water. Irradiation intensity of black light on the surface of roll A at the time of flaw detection: 1000 μm / cm ² (measured by UV-2500II UV intensity meter) It was possible to detect fine cracks existing at right angles and in parallel with. The time required for flaw detection on the entire circumference and the entire length of one roll A was about 1.5 minutes.

[0026]

EFFECTS OF THE INVENTION Since the present invention has the above-described configuration, the lower end surface (magnetic pole) of the leg iron core of the rotating magnetic field pole magnetizer is connected to the surface of the steel rolling roll to be flaw-detected. In the non-contact state, the magnetic flux can be effectively introduced to improve the accuracy of magnetic particle inspection, and the magnetization can be performed while rotating the roll, so that the speed of magnetic particle inspection can be increased. Further, when the distance control means is additionally provided, the distance between each lower end surface of the leg iron core and the roll surface can always be kept constant, so that the accuracy can be further improved.

[Brief description of drawings]

FIG. 1 is a side view of a magnetizing device for magnetic particle flaw detection of a rolling roll according to the present invention.

FIG. 2 is a front view of a magnetizing device for magnetic particle flaw detection of a rolling roll according to the present invention.

FIG. 3 is a perspective explanatory view schematically showing the structure of a rotating field magnetizer in the present invention.

FIG. 4 is a block diagram showing the interval control means in the present invention.

FIG. 5 is a partially omitted side explanatory view schematically showing the positional relationship between the shape of the lower end surface of the leg iron core of the rotating magnetic field pole magnetizer and the circumferential surface of the steel rolling roll which is the flaw detection target.

[Explanation of symbols]

 1 Rotating magnetic field pole magnetizer 11 H-shaped upper iron core 12, 13, 14, 15 Leg iron core 16, 17, 18, 19 Excitation coil 2 Magnetizer mounting base 21, 22 Support 23 Cross girder 24 Horizontal bar 25 Plate 3 Rolling roll carrier 31 Base 32, 33 Wheel 34 Frame 35, 36 Rotating roller mechanism 4 Rail 5 Excitation coil output terminal 6 Comparator 7 Computing unit 8 Controller A Steel rolling roll

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichi Hasegawa 12 Nakamachi, Muroran City, Muroran, Nippon Steel Co., Ltd. Muroran Works (72) Creator Masamune Motoyama 641 Funakuracho, Yokosuka City, Kanagawa Mark Tech Co., Ltd. (72) Creator Yasuhiro Kobayashi 641 Funakuracho, Yokosuka City, Kanagawa Mark Tech Co., Ltd.

Claims (3)

[Scope of utility model registration request] 1. An H- or X-shaped upper iron core provided with four leg iron cores having the same length that hang down from each tip portion, and an exciting coil wound around the four iron iron cores. The lower end surface of each leg iron core of the rotating magnetic field pole magnetizer is an inward slope, and this rotating magnetic field pole magnetizer is mounted on the magnetizer mount so that it can move vertically and horizontally. In front of the gantry, there is provided a rolling roll-carrying trolley that can rotatably support the rolling roll that is the flaw detection target and can move back and forth.
A magnetizing device for magnetic particle flaw detection of a rolling roll, wherein the inspection surface of the rolling roll mounted on the truck is magnetized just below the lower end surface of each leg core of the rotating magnetic field pole magnetizer. 2. The magnetizing device for magnetic particle flaw detection of a rolling roll according to claim 1, wherein the inclination angle of the inclined surface facing the inner side of the lower end surface of each leg iron core of the rotating magnetic field pole magnetizer is about 25 °. 3. An exciting coil of a rotating magnetic field pole magnetizer is provided with an output terminal for detecting a change in impedance of the coil, the output terminal is connected to a comparator, and the comparator is connected to a calculator. The magnetic particle flaw detection of a rolling roll according to claim 1, wherein the arithmetic unit is connected to a controller, and the controller controls the vertical movement position of the rotating magnetic field pole magnetizer mounted on the magnetizer mounting base. Magnetizing device.