JP6131772B2 - Roll for steel strip defect detection device - Google Patents

Description

  The present invention relates to a roll for a defect detection device used for a steel strip defect detection device in cold rolling equipment, surface treatment equipment, or the like.

  As a method for detecting defects existing in a magnetic material such as a steel strip, a leakage magnetic flux method is widely used. Patent Document 1 describes a steel strip defect detection device using a leakage magnetic flux method. FIG. 1 shows a defect detection apparatus described in Patent Document 1. The defect detection apparatus 1 includes a magnetization yoke 2 for magnetizing a thin steel plate, and a magnetic sensor 3 provided on the magnetization yoke 2. A traveling steel strip 5 is wound around a nonmagnetic roll 4 provided at a predetermined interval from the magnetic sensor 3. In such a defect detection device 1, when an excitation current is supplied, a closed magnetic path is formed by the magnetization yoke 2 and the traveling steel strip 5. If there is a defect on the surface or inside of the steel strip 5, the magnetic resistance inside the steel strip 5 changes and a leakage magnetic flux is generated. This leakage magnetic flux is detected by the magnetic sensor 3.

  The reason for using the non-magnetic roll 4 is that if the roll material has magnetism, the leakage magnetic flux is disturbed and noise is generated in the detection signal. The material of the roll may be a nonmagnetic steel material, for example, nonmagnetic stainless steel. As shown in FIG. 2, the nonmagnetic roll 4 has a hollow shape and is formed of a roll body 6 made of a nonmagnetic steel material. The nonmagnetic roll 4 is fixed by a rotating shaft 8 supported by a bearing 7.

  In cold rolling equipment, surface treatment equipment, and the like, large tension is applied to the steel strip in order to stably perform various treatments on the steel strip. Since the steel strip is wound at a predetermined winding angle on the non-magnetic roll, a load corresponding to the tension and winding angle of the steel strip acts. In addition, the weight of the steel strip is added to the load for the non-magnetic roll.

  If the load due to the tension and weight of the steel strip (hereinafter referred to as the load from the steel strip) is large, the non-magnetic roll will bend and the distance between the magnetic sensor and the steel strip will change in the width direction of the steel strip. Thus, the threshold value of the defect detection device also changes in the width direction. Therefore, by increasing the diameter of the nonmagnetic roll and the thickness of the roll body, rigidity is increased and roll deflection is suppressed.

  However, when the rigidity of the roll is increased, the inertial force with respect to the rotation of the roll, that is, the moment of inertia of the roll increases, and there is a case where slippage occurs between the non-magnetic roll and the steel strip to generate a scrape on the surface of the steel strip. . That is, in a cold rolling facility, a surface treatment facility, or the like, a steel strip is transported by a transport facility, and acceleration / deceleration is repeated. When the moment of inertia of the roll is large during acceleration / deceleration, a difference occurs between the acceleration / deceleration rate of the roll and the acceleration / deceleration rate of the steel strip. As a result, a difference occurs between the peripheral speed of the roll and the traveling speed of the steel strip, and slip occurs.

  On the other hand, in order to reduce the moment of inertia of the roll, Patent Document 2 describes a roll of low inertia. Patent Documents 3 to 5 describe low inertia rolls using fiber reinforced plastic as a roll material.

JP 2008-151744 A JP 2000-272737 A JP 2003-340512 A JP-A-11-125238 JP-A-6-292917

  As described above, when the rigidity of the nonmagnetic roll is improved, the inertial force with respect to the rotation of the roll is increased. When the inertial force is increased, slip may occur between the nonmagnetic roll and the steel strip, which may cause a scum on the surface of the steel strip. In this case, in order to prevent the occurrence of slip, a nonmagnetic roll driving device for adjusting the difference between the acceleration / deceleration rate of the roll and the acceleration / deceleration rate of the steel strip is required. However, when a defect detection device is installed in an existing facility, a space for installing a non-magnetic roll drive facility is also required, which makes it difficult to arrange the defect detection device. In addition, it will be necessary to relocate existing equipment and change the steel strip transport path length. As a result, enormous costs are required.

  On the other hand, the low inertia roll using the fiber reinforced plastic as described in Patent Documents 3 to 5 can endure being used under the conditions of high speed and high load necessary as a roll for a defect detection device. It does not have rigidity.

  Even if a non-magnetic roll such as stainless steel is used, it is not a perfect non-magnetic material but a weak magnetic material having magnetic permeability, so noise is detected during detection by the leakage magnetic flux method. Depending on the size, the accuracy of defect detection is reduced.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the roll for defect detection apparatuses of a low inertia and nonmagnetic.

The gist of the present invention is as follows.
[1] A laminated structure in which the outside of the hollow roll body is made of nonmagnetic fiber-reinforced plastic, and the inside of the hollow roll body is made of a nonmagnetic steel material. A roll for a defect detection device.
[2] The defect detection device roll according to [1], wherein the roll body is rotatably attached to a fixed roll shaft.

  The roll for defect detection device of the present invention has a structure in which the outer side of the roll body is laminated with a nonmagnetic fiber reinforced plastic and the inner side with a nonmagnetic steel material, so that a low inertia and nonmagnetic roll is provided. be able to. Moreover, since the roll for defect detection apparatuses of this invention is highly rigid, it can suppress roll bending. Furthermore, since a drive device is not required, the defect detection device can be installed with existing equipment. Furthermore, since the outer side of the roll body is made of non-magnetic fiber reinforced plastic, noise caused by the magnetic flux of the roll material can be prevented and detection accuracy can be improved.

It is a figure showing the conventional defect detection apparatus. It is sectional drawing of the roll for the conventional defect detection apparatus. It is sectional drawing which shows an example of the roll for defect detection apparatuses which concerns on embodiment of this invention. It is sectional drawing which shows an example of the roll for defect detection apparatuses which concerns on embodiment of this invention.

  The roll for defect detection device of the present invention has a hollow roll body, the outer roll body is formed of nonmagnetic fiber reinforced plastic, and the inner roll body is nonmagnetic steel material. It is formed by.

  FIG. 3 is a cross-sectional view showing an example of a roll for defect detection apparatus (hereinafter also referred to as a nonmagnetic roll or roll) 9 according to an embodiment of the present invention. The roll 9 for a defect detection device of the present invention includes a hollow roll body 6, a bearing 7 that supports rotation of the roll body 6, and a fixed shaft 10 that supports the bearing 7. The hollow roll body 6 has a double structure formed of two kinds of materials. The outer roll body 11 is made of non-magnetic fiber reinforced plastic. The inner roll body 12 is made of a nonmagnetic steel material.

  The roll for defect detection apparatus of the present invention is a fiber reinforced plastic having a weight lower than that of nonmagnetic steel material and having high strength equivalent to that of nonmagnetic steel material. Laminated on the outside. For this reason, high rigidity can be maintained and low inertia can be achieved. Therefore, no slip occurs between the nonmagnetic roll and the steel strip. As a result, it is possible to prevent the occurrence of scouring on the surface of the steel strip. Furthermore, it does not require a new driving device, and has low inertia and excellent rotational performance.

  Table 1 shows mechanical properties of nonmagnetic stainless steel, which is an example of a conventionally used nonmagnetic steel material, and carbon fiber reinforced plastic, which is an example of the fiber reinforced plastic of the present invention.

  As shown in Table 1, it is possible to maintain high rigidity and low inertia by using a nonmagnetic carbon fiber reinforced plastic having a small specific gravity and high strength compared to conventional nonmagnetic steel materials. it can. Furthermore, since the magnetic permeability of nonmagnetic stainless steel is higher than the magnetic permeability of carbon fiber reinforced plastic, it can be said that the influence of noise on the defect detection device is small. Therefore, as in the present invention, by laminating the fiber reinforced plastic on the outside, noise caused by the magnetic flux of the roll material can be prevented and detection accuracy can be improved.

  The fiber-reinforced plastic used for the outer roll body is not particularly limited. From the viewpoint of strength, carbon fiber reinforced plastic (CFRP) is preferable.

  As a nonmagnetic steel material used for the inner roll body, for example, nonmagnetic stainless steel is preferable, and for example, heat-resistant cast steel HH-2 can be mentioned.

  The roll shaft of the roll for defect detection apparatus of the present invention is a fixed shaft 10 as shown in FIG. 3, and the roll body 6 only needs to be rotatably attached to the fixed shaft 10. In addition, as shown in FIG. 4, slips occur between the nonmagnetic roll and the steel strip depending on the load of the steel strip on the nonmagnetic roll, the winding angle of the steel strip on the nonmagnetic roll, and the acceleration / deceleration rate of the steel strip transport equipment. In consideration of the degree of influence to be generated, a rotation type in which the roll axis is the rotation axis 8 may be used. In order to reduce the moment of inertia, the roll body 6 is preferably rotatably attached to a fixed shaft 9 as shown in FIG.

  As described above, the roll for defect detection device of the present invention has a small noise influence on the defect detection device due to the magnetic flux of the roll material. Therefore, by using the roll for defect detection apparatus of the present invention, even a minute defect can be detected stably without degrading the detection accuracy.

  As an example of the present invention, the roll for defect detection apparatus shown in FIG. 3 was used. In order to reduce the moment of inertia, the nonmagnetic roll of FIG. 3 has a structure in which the roll shaft is the fixed shaft 3 and only the roll body rotates. The outer roll cylinder 11 was made of carbon fiber reinforced plastic (CFRP) as a fiber reinforced plastic. For the inner roll cylinder 12, heat-resistant cast steel HH-2 was used as a nonmagnetic steel material.

  For the inventive example and the conventional example, the moment of inertia and the roll deflection were examined. The load is an external force of 60.9 kN (considering its own weight).

  From the results in Table 2, compared to the conventional example, the example of the present invention in FIG. 3 (roll shaft rotation) realized an inertia moment of 7/10 and a roll deflection of 6.6 / 10.

  Further, by using the roll for defect detection device of the present invention, it was possible to realize the installation of the defect detection device in the existing facility without modifying the existing facility. As a result, it was possible to prevent an increase in equipment costs due to large-scale remodeling of existing equipment, and to minimize the production stoppage period due to long-term remodeling work. In addition, it is possible to improve the yield by using a steel strip defect detection device and to reduce the cost of the next process when a defect occurs.

  As described above, according to the present invention, since the roll body is laminated with the nonmagnetic fiber reinforced plastic on the outside and the nonmagnetic steel material on the inside, the low inertia and nonmagnetic roll is formed. Can be provided. Also, to provide a non-magnetic low inertia roll as a roll for a defect detection device that does not require a driving device and does not generate scouring on the surface of the steel strip due to slip occurring between the roll and the steel strip. Can do.

DESCRIPTION OF SYMBOLS 1 Defect detection apparatus 2 Magnetization yoke 3 Magnetic sensor 4 Nonmagnetic roll (roll)
5 Steel strip 6 Roll body 7 Bearing 8 Rotating shaft 9 Defect detection device roll (non-magnetic roll, roll)
10 Fixed shaft 11 Outside roll body 12 Inside roll body

Claims (2)

The outside of the hollow roll body is formed of a nonmagnetic carbon fiber reinforced plastic, and the inside of the hollow roll body is a laminated structure formed of a nonmagnetic steel material. Roll for steel strip defect detection equipment. The roll for steel strip defect detection device according to claim 1, wherein the roll body is rotatably attached to a fixed roll shaft.

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