Cradle roll and metal strip handling method using the same

Abstract

To provide a cradle roll capable of preventing defects from occurring in a coil.SOLUTION: This cradle roll metal strip having an annular recess into which a metal strip coil binding hoop is inserted comprises a lining on the surface. The annular recess corresponds to an omitted part of the lining. On a cross-section parallel to a roll shaft direction, the cross-sectional shape of a corner from the roll surface of the lining to the annular recess is a projected curve. The metal strip handling method performs metal strip end processing and packaging or continuously performs delivering / winding. A plurality of kinds of the end processing are mixed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cradle roll for performing end processing, packaging, unloading, and winding of a metal strip, and to a method for handling a metal strip using the same. [Background technology]

[0002] Metal strip coils, for example, steel strip coils (steel sheet winding coils) (hereinafter simply referred to as coils), are often handled by cradle rolls. For example, by rotating the coil on the cradle roll, the steel sheet may be dispensed and wound for the purpose of inspecting the steel sheet surface and removing peripheral defects. On the other hand, when storing or transporting the coil, the coil is bound with a steel hoop to prevent the outer circumference from warping and loosening due to the rigidity of the steel sheet (Figure 3(a)). When the coil is transported on the cradle roll, if the hoop and the roll come into contact with each other, the surface pressure between the hoop and the coil increases, and this may cause scratches on the coil. For this reason, the cradle roll is generally used with an annular recess formed to avoid the hoop. This recess also plays a role in inserting the hoop when removing the hoop or when putting the hoop on. For example, a cradle roll 5 as shown in Figure 4 is used. In this cradle roll 5, a lining 2 is applied to the surface of the roll body 3, and the annular recess 6 is formed by a missing part of the lining 2. The coil 1 is placed on the roll surface of the lining 2.

[0003] The thinner the steel plate, the lower its rigidity becomes. For steel plates with a thickness of less than 0.5 mm, there is almost no warping of the coil periphery. For this reason, it is common to use adhesive tape or the like to bond the coil without using a bundling hoop (Fig. 3(b)). For steel plates with a thickness of less than 0.4 mm, the rigidity is even lower, and there is a problem that when the coil is rotated on the cradle roll, a squeezing defect originating from the annular recess occurs. For coils with a thickness of less than 0.4 mm, therefore, a cradle roll without an annular recess is used for unwinding and winding, and adhesive tape is used for bonding. When handling coils with different thicknesses, the cradle roll must be replaced, which is inefficient. There was also a problem of increased costs due to the need to prepare two types of rolls.

[0004] Therefore, for example, Patent Document 1 proposes a cradle roll in which the outer periphery of the roll is divided into shells in the axial direction, and the two shells are moved to close the annular recess, thereby changing the roll into a continuous roll without the annular recess, thereby preventing defects from occurring regardless of the presence or absence of a hoop and the plate thickness. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-001430 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned conventional techniques have the following problems. That is, the technology described in Patent Document 1 is intended to improve defects in steel sheets that do not have a coating on the surface. However, when a coating is present, defects may occur even with the technology described in Patent Document 1.

[0007] The present invention has been made in view of the above, and has an object to provide a cradle roll that does not cause scratches even in a coil having a coating. It is also an object to propose a method for handling a metal strip using the cradle roll. In the present invention, the metal strip coil refers to a metal strip wound in a coil shape. The metal strip is used without distinction between a coil shape and a case where it is not wound in a coil shape. The same applies to a steel strip coil and a steel strip. [Means for solving the problem]

[0008] The inventors conducted extensive research to achieve the above-mentioned object, and as a result, obtained the following findings. That is, it was found that when a coil is handled by a cradle roll having an annular recess, defects occurring on a coil having a film coating on its surface include defects originating from the corners of the lining that reach the annular recess, and other surface defects. It was found that the shape of the lining corners affects the defects originating from the corners of the lining. It was also found that the hardness of the lining affects the other surface defects. The other surface defects refer to defects originating from the surface of the lining excluding the corners of the lining that reach the annular recess.

[0009] The cradle roll of the present invention, which advantageously solves the above-mentioned problems, is a cradle roll having an annular recess through which a hoop for bundling a metal strip coil is inserted, and is characterized in that a lining is provided on the surface of the cradle roll, the annular recess corresponds to a missing portion of the lining, and in a cross section parallel to the roll axial direction, the cross-sectional shape of the corner from the roll surface of the lining to the annular recess is a convex curve.

[0010] The cradle roll according to the present invention is (a) the ratio b / a of the length b of the convex curve in the roll axial direction to the length a of the roll radial direction is in the range of 1 to 5, and the length a of the roll radial direction is in the range of 0.1 to 0.8 times the thickness t of the lining, (b) the hardness of the lining is in the range of 90 to 98 as measured with a type A durometer conforming to JIS K 6253-3:2012; would be a more preferable solution.

[0011] The metal strip handling method of the present invention, which advantageously solves the above problem, is a metal strip handling method which uses any of the cradle rolls described above to perform end processing, packaging, or continuous paying out and winding of the metal strip, and is characterized in that multiple types of end processing are mixed together.

[0012] The metal strip handling method according to the present invention is further characterized in that metal strips of different widths are handled together. Effect of the Invention

[0013] According to the cradle roll and the method for handling a metal strip of the present invention, by specifying the shape of the corners of the lining leading to the annular recess, even if the coil has a coating, defects originating from the corners of the lining are not generated. In addition, since the hardness of the lining is specified, other surface defects are not generated even if the coil has a coating. Therefore, the quality of the coil is improved, the yield is improved, and the cost is reduced, which is industrially useful. [Brief description of the drawings]

[0014] [Figure 1] 1A and 1B are conceptual diagrams showing the configuration of a cradle roll according to one embodiment of the present invention, in which (a) is a schematic cross-sectional view and (b) is a partially enlarged view. [Diagram 2] 5A and 5B are schematic diagrams showing a state in which the cradle roll according to the embodiment is used, in which (a) is a front view and (b) is a side view. [Diagram 3] (a) shows the state where a coil bound with a hoop is loaded, and (b) shows the state where a coil adhered with adhesive tape is loaded. [Figure 4]1A and 1B are conceptual diagrams showing the configuration of a conventional cradle roll having an annular recess, in which (a) is a schematic cross-sectional view and (b) is a partially enlarged view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. Note that the following embodiments are merely examples of devices and methods for embodying the technical idea of ​​the present invention, and are not intended to limit the configuration to the following. In other words, the technical idea of ​​the present invention can be modified in various ways within the technical scope described in the claims.

[0016] Fig. 1 is a conceptual diagram showing the configuration of a cradle roll according to one embodiment of the present invention, where Fig. 1(a) is a schematic cross-sectional view and Fig. 1(b) is a partially enlarged view. Fig. 2 is a schematic diagram showing the use of the cradle roll according to the embodiment, where Fig. 2(a) is a front view and Fig. 2(b) is a side view. Fig. 3(a) shows a state in which a coil bound by a hoop is loaded, and Fig. 3(b) shows a state in which a coil adhered by an adhesive tape is loaded.

[0017] End treatment of a metal strip coil, for example, end treatment of a steel strip coil with a thickness of 0.5 mm or more, is performed with a bundling hoop 7, while end treatment of a steel strip coil with a thickness of less than 0.5 mm is performed with an adhesive tape 8. A plurality of bundling hoops 7 and adhesive tapes 8 may be used for each.

[0018] In this embodiment, the cradle roll 5 has an annular recess 6. Therefore, by arranging the bundling hoop 7 so as to pass through the annular recess 6, as in the conventional case, defects caused by the bundling hoop 7 can be prevented.

[0019] In this embodiment, in a cross section parallel to the roll axis direction of the cradle roll 5, the cross-sectional shape of the corner from the roll surface of the lining 2 to the annular recess 6 is formed as a convex curve. Therefore, the change in contact pressure between the metal strip and the lining becomes gentle, so that surface defects originating from the corner from the roll surface of the lining 2 to the annular recess 6 can be suppressed. For example, when the organic resin coating is applied at a rate of 0.2 to 2.0 g / m 2 Metal strips having a thickness of less than 0.4 mm can be handled without surface defects. Metal strips plated with soft metals such as zinc plating or aluminum plating can be handled without surface defects. Furthermore, steel strip coils having a thickness of less than 0.4 mm can be handled without drawing defects, so that the annular recess 6 can be used without closing. When the metal strip is a steel strip, for example, the thickness is in the range of 0.3 to 3.3 mm, and the width is in the range of 650 to 1850 mm.

[0020] The convex curve 4 formed by the cross-sectional shape of the corner from the roll surface of the lining 2 to the annular recess 6 may be a circular arc, an elliptical arc, a tapered shape, or the like. The tapered shape includes a parabola. It may also be composed of multiple straight lines inscribed in the convex curve 4. The cross-sectional shape of the corner from the roll surface of the lining 2 to the annular recess 6 is based on a step shape with a right angle corner, and the length in the roll axial direction from the point where the roll surface and the convex curve 4 contact each other to the side wall of the annular recess 6 is set as the length b of the convex curve 4 in the roll axial direction. The length in the roll radial direction from the point where the convex curve 4 contacts the side wall of the annular recess 6 to the roll surface is set as the length a of the convex curve 4 in the roll radial direction.

[0021] It is preferable that the ratio b / a of the length b of the convex curve 4 in the roll axial direction to the length a of the convex curve 4 in the roll radial direction is in the range of 1 to 5, and the length a of the convex curve 4 in the roll radial direction is in the range of 0.1 to 0.8 with respect to the thickness t of the lining 2, in terms of a / t. When the convex curve 4 is a quadrant arc, a=b, which means that a / b=1. The thickness t of the lining 2 depends on the plate thickness of the hoop and the degree of wear of the lining 2, but is about 5 to 20 mm when handling a steel strip coil, for example. By setting the length a of the convex curve 4 in the roll radial direction to the range of 0.1 to 0.8 times the thickness t (mm) of the lining 2, the reaction force of the lining 2 can be applied to the metal strip coil so as to gradually increase from the annular recess 6 toward the steady pressing portion of the lining 2. It is more preferable that b / a is in the range of 1 to 3, and more preferably a / t is in the range of 0.2 to 0.3. By setting the shape of the convex curve 4 within the above range, for example, when the coil 1 is loaded on the cradle roll 5 as shown in Figure 2, it is possible to prevent the reaction force from the corner of the lining 2 on the annular recess 6 side from being concentrated on the coil 1.

[0022] In this embodiment, the hardness of the rubber that is the material of the lining 2 is preferably in the range of 90 to 98 as measured by a type A durometer conforming to JIS K 6253-3:2012. Within this range, for example, a metal strip coil coated with an organic resin film can be handled without other surface defects. If the hardness of the lining 2 exceeds the upper limit, for example, the hardness of the lining becomes too high compared to the coating of the metal strip, and other surface defects may occur on the metal strip. Furthermore, if the hardness of the lining is within the above range, defects such as wear and residual deformation of the lining 2 are unlikely to occur when a steel strip coil with a width within the above range is loaded. For example, if the hardness of the lining is too low, scratches and deformations will occur on the lining at the coil width edges, and if the processing is performed in order from narrow to wide, the scratches and deformations of the lining will be transferred to the surface of the subsequent coil.

[0023] Another embodiment of the present invention is a metal strip handling method that uses the cradle roll of the above embodiment to perform end processing, packaging, or continuous unloading and winding of the metal strip, and is suitable for use in cases where a plurality of types of end processing are mixed. Examples of the plurality of end processing include a metal strip coil bound by a hoop as shown in FIG. 3(a) and a metal strip coil whose tail end is adhered with an adhesive tape as shown in FIG. 3(b). Examples of the metal strip handling method include packaging the coil 1, unloading and winding on a metal strip inspection line or defect removal line, etc. In this embodiment, regardless of the end processing of the metal strip, it is possible to handle a metal strip that is free of two types of defects, namely, defects originating from the corners of the lining and other surface defects.

[0024] Furthermore, the method for handling a metal strip according to the present embodiment uses a cradle roll with a specified hardness of the lining, and can handle end treatment, packaging, or continuous unloading and winding of a mixture of metal strip coils with different widths. Regardless of the width of the metal strip, the metal strip can be handled without generating other surface defects. EXAMPLES

[0025] The present invention will be described in detail below with reference to examples. On a metal strip inspection line, cold-rolled steel coils with thicknesses ranging from 0.3 to 3.3 mm and widths ranging from 650 to 1850 mm were inspected. The coils used were steel sheets with a coating that is prone to scratches on the surface. On this inspection line, a cradle roll was used to remove the steel sheets from the coils, and a grinding inspection was performed.

[0026] Example 1 First, for the cradle roll shown in Fig. 1, the thickness t of the rubber lining was 10 mm, the convex curve of the corner of the annular recess was a circular arc with a=b, and the radius R (=a=b) was 1 mm. In this case, b / a was 1, and a / t was 0.1. The hardness of the rubber was 88 as measured by a type A durometer conforming to JIS K 6253-3:2012. In this cradle roll, all the coils with the organic coating had no defects originating from the lining corner, but other surface defects occurred.

[0027] Example 2 Second, as shown in Fig. 1, the thickness t of the rubber lining was 10 mm, the convex curve of the corner of the annular recess was an elliptical arc, the length a in the roll radial direction was 1 mm, and the length b in the roll axial direction was 6 mm. In this case, b / a was 6, and a / t was 0.1. The hardness of the rubber was 88 as measured by a type A durometer conforming to JIS K 6253-3:2012. In this cradle roll, two types of defects occurred on the coil with the organic coating.

[0028] Example 3 Thirdly, a cradle roll with a right-angled corner of the annular recess shown in Fig. 4 was used. The thickness t of the rubber lining was 10 mm, there was no convex curve at the corner, and a / t was considered to be 0. In addition, the hardness of the rubber was 90 as measured with a type A durometer conforming to JIS K 6253-3:2012. In this cradle roll, defects originating from the lining corners occurred in all coils with an organic coating.

[0029] Example 4 Fourthly, a cradle roll according to the embodiment of the present invention shown in Fig. 1 was used. The thickness t of the rubber lining was 10 mm, the convex curve of the corner of the annular recess was a circular arc of a=b, and the radius R (=a=b) was 2 mm. In this case, b / a was 1, and a / t was 0.2. In addition, two types of rubber hardness were used, 90 and 98, measured with a type A durometer conforming to JIS K 6253-3:2012. Both cradle rolls were able to suppress the occurrence of two types of defects regardless of the presence or absence of hoop binding and the presence or absence of coating, and it was found that work can be performed on a line that handles a wide variety of steel plates without the need to change the roll or switch the mode, such as opening and closing the annular recess. [Industrial Applicability]

[0030] According to the cradle roll and metal strip handling method of the present invention, no defects are generated in the coil regardless of whether it is hoop bound or not, whether the coil width is different, whether it is coated or not, or the plate thickness, thereby improving productivity and being industrially useful. [Explanation of symbols]

[0031] 1 coil 2. Lining 3 Roll body 4. (at the corner of a circular recess) a convex curve 5 Cradle Roll 6 Circular recess (missing part) 7. Binding Hoops 8. Adhesive Tape

Claims

1. A cradle roll having an annular recess through which a metal strip coil bundling hoop is inserted, A lining is provided on the surface of the cradle roll, The annular recess corresponds to a missing portion of the lining, In a cross section parallel to the roll axial direction, the cross-sectional shape of a corner from the roll surface of the lining to the annular recessed portion is a convex curve. Cradle roll.

2. The convex curve has a ratio b / a of a length b in the roll axial direction to a length a in the roll radial direction in a range of 1 to 5, and the length a in the roll radial direction is in a range of 0.1 to 0.8 times the thickness t of the lining. The cradle roll of claim 1.

3. Furthermore, the hardness of the lining is in the range of 90 to 98 as measured with a type A durometer conforming to JIS K 6253-3:2012. The cradle roll according to claim 1 or 2.

4. Using the cradle roll according to claim 1 or 2, A method for handling metal strips for end processing, packaging, or continuous unloading and winding, comprising the steps of: The end treatments are of multiple types, How to handle metal strips.

5. Using the cradle roll according to claim 3, A method for handling metal strips for end processing, packaging, or continuous unloading and winding, comprising the steps of: The end treatments are of multiple types, How to handle metal strips.

6. Furthermore, we handle metal strips of different widths together, 6. A method for handling metal strip according to claim 5.

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