Cradle roll and method for handling metal strips using the same
The cradle roll with a convex curve and specified hardness addresses defects in metal strips with surface coatings, enabling efficient handling of diverse metal strips without roll changes, enhancing coil quality and reducing costs.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- JFE STEEL CORP
- Filing Date
- 2023-08-02
- Publication Date
- 2026-07-07
AI Technical Summary
Conventional cradle rolls cause defects in metal strips with surface coatings due to the shape and hardness of the lining corners leading to annular recesses, and require separate rolls for different thicknesses and coatings, leading to inefficiency and increased costs.
A cradle roll with an annular recess and a convex curve at its corners, where the ratio of the length in the roll axis direction to the radial direction of the lining is 1 to 5, and the lining hardness is between 90 to 98 on the Type A durometer scale, preventing defects by distributing the reaction force gently.
Prevents defects on metal strips with surface coatings and allows handling of varying thicknesses and coatings without roll changes, improving coil quality and reducing costs.
Smart Images
Figure 0007885745000001 
Figure 0007885745000002 
Figure 0007885745000003
Abstract
Description
Technical Field
[0001] The present invention relates to a cradle roll for end processing, packing, paying out, and winding of a metal strip, and to a method for handling a metal strip using the same.
Background Art
[0002] Metal strip coils, for example, steel strip coils (steel sheet wound coils) (hereinafter, also 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 paid out and wound for the purpose of inspecting the surface of the steel sheet and removing outer peripheral defects. On the other hand, when storing and transporting the coil, in order to prevent the outer periphery from warping and unwinding due to the rigidity of the steel sheet, it is bound with a steel hoop (Fig. 3(a)). When the coil is transported onto the cradle roll, if the hoop and the roll come into contact, the surface pressure between the hoop and the coil increases, and indentations may occur on the coil. Therefore, it is common to use a cradle roll formed with an annular recess to avoid the hoop. This recess also serves to insert the hoop when removing or attaching the hoop. For example, a cradle roll 5 as shown in Fig. 4 is used. This cradle roll 5 has a lining 2 applied to the surface of the roll body 3, and the annular recess 6 is formed by a missing portion of the lining 2. The coil 1 is loaded onto the roll surface of the lining 2.
[0003] The rigidity of steel plates decreases as their thickness decreases, and steel plates less than 0.5 mm thick exhibit almost no warping around the coil's outer circumference. Therefore, it is common practice to bond them with adhesive tape or similar methods without using binding hoops (Figure 3(b)). When the plate thickness is less than 0.4 mm, the rigidity decreases even further, and rotating the coil on a cradle roll can cause drawing defects originating from the annular recess. Therefore, when inspecting coils less than 0.4 mm thick, a cradle roll without annular recesses is used for dispensing, winding, and bonding with adhesive tape. When handling coils of different thicknesses together, it is necessary to change the cradle roll, resulting in poor work efficiency. Furthermore, the need to prepare two types of rolls increases costs.
[0004] For example, Patent Document 1 proposes a cradle roll that does not generate defects regardless of the presence or absence of hoops or plate thickness, by dividing the outer circumference of the roll into shells in the axial direction and moving the two shells to close the annular recess, thereby changing it into a continuous roll without an annular recess. [Prior art documents] [Patent Documents]
[0005] [Patent Document 1] Japanese Patent Publication No. 2002-001430 [Overview of the project] [Problems that the invention aims to solve]
[0006] However, the above-mentioned conventional technology had the following problems. In other words, the technology described in Patent Document 1 is intended to improve defects in steel sheets that do not have a surface coating. However, even with the technology described in Patent Document 1, defects sometimes occurred when a surface coating was present.
[0007] The present invention has been made in view of the above, and aims to provide a cradle roll that does not cause defects even in coils having a film coating. Furthermore, it aims to propose a method for handling metal strips using the cradle roll. In this invention, a metal strip coil refers to a metal strip wound into a coil shape. Also, the term "metal strip" is used without distinction between a coil shape and a strip that is not wound into a coil shape. The same applies to steel strip coils and steel strips. [Means for solving the problem]
[0008] The inventors conducted extensive research to achieve the above-mentioned objectives and obtained the following findings. Specifically, they found that when handling coils with a cradle roll having an annular recess, defects occurring on coils with a surface coating include defects originating from the corner of the lining leading to the annular recess and other surface defects. They found that the shape of the corner of the lining influences the defects originating from the corner of the lining. They also found that the hardness of the lining influences the other surface defects. Note that "other surface defects" refers to defects originating from the surface of the lining, excluding the corner of the lining leading to the annular recess.
[0009] The present invention, which advantageously solves the above problems, is a cradle roll having an annular recess through which a metal strip coil bundling hoop is inserted, wherein the surface of the cradle roll is provided with a lining, the annular recess corresponds to a missing portion of the lining, and in a cross section parallel to the roll axis direction, the cross-sectional shape of the corner from the roll surface of the lining to the annular recess is a convex curve.
[0010] Furthermore, the cradle roll according to the present invention is (a) The convex curve has a ratio b / a of the length b in the roll axis direction to the length a in the roll radial direction, which is in the range of 1 to 5, and the length a in the roll radial direction is in the range of 0.1 times or more and 0.8 times or less the thickness t of the lining. (b) Furthermore, the hardness of the lining shall be in the range of 90 to 98 when measured with a Type A durometer in accordance with JIS K 6253-3:2012. This would be a more preferable solution.
[0011] The present invention provides a method for handling metal strips that advantageously solves the above problems, and is a method for handling metal strips that uses any of the above-mentioned cradle rolls to process the ends of the metal strips, package them, or continuously discharge and wind them, characterized in that multiple types of end processing are mixed together.
[0012] Furthermore, the method for handling metal strips according to the present invention is characterized by handling metal strips of different widths together. [Effects of the Invention]
[0013] According to the present invention, the method for handling cradle rolls and metal strips prevents defects originating from the lining corners by specifying the shape of the corners of the lining leading to the annular recess. Furthermore, since the hardness of the lining is specified, other surface defects are also prevented, even in coils with a film coating. Therefore, the quality of the coils is improved, the yield is increased, and costs are reduced, making it industrially useful. [Brief explanation of the drawing]
[0014] [Figure 1] This is a conceptual diagram showing the configuration of a cradle roll according to one embodiment of the present invention, where (a) is a schematic cross-sectional view and (b) is a partially enlarged view. [Figure 2] This is a schematic diagram showing the usage state of the cradle roll according to the above embodiment, where (a) is a front view and (b) is a side view. [Figure 3] (a) shows a coil bound together with hoops and loaded, and (b) shows a coil attached with adhesive tape and loaded. [Figure 4]A conceptual diagram showing the configuration of a conventional cradle roll having an annular recess, where (a) is a schematic cross-sectional view and (b) is a partially enlarged view.
Embodiments for Carrying out the Invention
[0015] Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. Note that the following embodiments illustrate devices and methods for embodying the technical idea of the present invention, and do not specify the configuration to be the following. That is, the technical idea of the present invention can be variously modified within the technical scope described in the claims.
[0016] FIG. 1 is a conceptual diagram showing the configuration of a cradle roll according to an 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 usage state of the cradle roll according to the above embodiment, where FIG. 2(a) is a front view and FIG. 2(b) is a side view. FIG. 3(a) represents a state in which a coil bundled by a hoop is loaded, and FIG. 3(b) represents a state in which a coil adhered by an adhesive tape is loaded.
[0017] The end treatment of the metal strip coil, for example, the end treatment in a steel strip coil with a thickness of 0.5 mm or more is performed by the binding hoop 7, and a steel strip coil with a thickness of less than 0.5 mm is treated by the adhesive tape 8. In some cases, a plurality of binding hoops 7 or adhesive tapes 8 may be used respectively.
[0018] In this embodiment, the cradle roll 5 has an annular recess 6. Therefore, similar to the conventional case, by arranging the binding hoop 7 to be inserted into the annular recess 6, it is possible to prevent scratches caused by the binding hoop 7.
[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 by a convex curve. Therefore, the change in the contact pressure between the metal strip and the lining becomes gentle, so that surface defects starting from the corner from the roll surface of the lining 2 to the annular recess 6 can be suppressed. For example, a metal strip having an organic resin coating film of 0.2 to 2.0 g / m 2 can be handled without surface defects. Also, a metal strip with a soft metal plating such as zinc plating or aluminum plating can be handled without surface defects. Further, a steel strip coil with a thickness of less than 0.4 mm can be drawn without drawing defects, so that it can be used without closing the annular recess 6. 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 an arc, an elliptical arc, a tapered shape, etc. The tapered shape includes a parabola. Also, it may be composed of a plurality of straight lines inscribed in the convex curve 4. Taking the reference of the cross-sectional shape of the corner from the roll surface of the lining 2 to the annular recess 6 as a stepped shape with a right angle, the length in the roll axis direction from the point where the roll surface and the convex curve 4 contact to the side wall of the annular recess 6 is set as the length b in the roll axis direction of the convex curve 4. The length in the roll diameter 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 in the roll diameter direction of the convex curve 4.
[0021] It is preferable that the ratio b / a of the length b in the roll axis direction of the convex curve 4 to the length a in the roll radial direction is in the range of 1 to 5, and that the length a of the convex curve 4 in the roll radial direction is in the range of 0.1 to 0.8 in terms of a / t relative to the thickness t of the lining 2. Note that if the convex curve 4 is a quarter arc, then a=b, meaning a / b=1. The thickness t of the lining 2 depends on the thickness of the hoop and the degree of wear of the lining 2, but for example, when handling steel strip coils, it is about 5 to 20 mm. By having the length a of the convex curve 4 in the roll radial direction be in the range of 0.1 to 0.8 times the thickness t (mm) of the lining 2, the reaction force from the lining 2 can be applied to the metal strip coil in such a way that it gradually increases from the annular recess 6 toward the steady-state pressing portion of the lining 2. It is even more preferable that b / a be in the range of 1 to 3, and even more preferable that a / t be in the range of 0.2 to 0.3. By setting the shape of the convex curve 4 to the above range, for example, when the coil 1 is loaded onto the cradle roll 5 as shown in Figure 2, it is possible to avoid the reaction force from the corner of the lining 2 on the annular recess 6 side concentrating on the coil 1.
[0022] In this embodiment, the hardness of the rubber material of the lining 2 is preferably in the range of 90 to 98 when measured with a Type A durometer compliant with JIS K 6253-3:2012. Within this range, for example, metal strip coils 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 will be too high compared to the coating on the metal strip, which may cause other surface defects on the metal strip. Also, if the hardness of the lining is within the above range, it is less likely that defects such as wear and residual deformation of the lining 2 will occur when steel strip coils of a width within the above range are loaded. For example, if the hardness of the lining is too low, defects and deformation will occur in the lining at the coil width edge, and if processing is performed sequentially from narrow to wide, the defects and deformation of the lining will be transferred to the surface of subsequent coils.
[0023] Another embodiment of the present invention is a method for handling metal strips, which uses the cradle roll of the above embodiment to perform end treatment, packaging, or continuous dispensing and winding of metal strips, and is suitable for use when multiple types of end treatments are mixed. Examples of multiple end treatments include, for example, a metal strip coil bound with a hoop as shown in Figure 3(a), and a metal strip coil whose tail end is bonded with adhesive tape as shown in Figure 3(b). Examples of metal strip handling methods include packaging coil 1, and dispensing and winding of metal strips in inspection lines and defect removal lines. In this embodiment, it is possible to handle metal strips without two types of defects, namely defects originating from the corners of the lining and other surface defects, regardless of the end treatment of the metal strips.
[0024] Furthermore, the metal strip handling method according to this embodiment allows for the use of a cradle roll with a specified lining hardness, enabling the mixing of metal strip coils with different widths for end treatment, packaging, and continuous dispensing and winding. This method allows for the handling of metal strips without causing other surface defects, regardless of the width of the metal strip. [Examples]
[0025] The present invention will be described in detail below based on the following examples. On a metal strip inspection line, coils of cold-rolled steel sheets with thicknesses ranging from 0.3 to 3.3 mm and widths ranging from 650 to 1850 mm were inspected. The coils used steel sheets with a surface coating that was prone to scratches. On this inspection line, the steel sheets were dispensed from the coils using cradle rolls and then subjected to grinding inspection.
[0026] (Example 1) Firstly, as shown in Figure 1, the cradle roll had a rubber lining thickness t of 10 mm, and the curve of the convex corner of the annular recess was a circular arc with radius R (=a=b) of 1 mm. In this case, b / a was 1 and a / t was 0.1. The hardness of the rubber was measured at 88 using a Type A durometer compliant with JIS K 6253-3:2012. In this cradle roll, none of the coils with organic coating had defects at the lining corner, but other surface defects were present.
[0027] (Example 2) Secondly, the cradle roll shown in Figure 1 had a rubber lining thickness t of 10 mm, the curve of the convex 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 measured at 88 using a Type A durometer compliant with JIS K 6253-3:2012. Two types of defects occurred in the coil coated with an organic film in this cradle roll.
[0028] (Example 3) Thirdly, a cradle roll with right-angle corners in the annular recess shown in Figure 4 was used. The thickness t of the rubber lining was 10 mm, there were no convex curves at the corners, and a / t was considered to be 0. The hardness of the rubber was measured at 90 using a Type A durometer compliant with JIS K 6253-3:2012. In this cradle roll, defects originating from the lining corner occurred in all coils with organic coating.
[0029] (Example 4) Fourthly, a cradle roll according to an embodiment of the present invention shown in Figure 1 was used. The thickness t of the rubber lining was 10 mm, and the curve of the convex corner of the annular recess was a circular arc with radius R (=a=b) of 2 mm. In this case, b / a was 1 and a / t was 0.2. In addition, two types of rubber hardness, 90 and 98, were used, measured using a Type A durometer compliant with JIS K 6253-3:2012. Both cradle rolls were able to suppress the occurrence of two types of defects regardless of whether hoop binding was used or whether a film coating was used, and it was found that work could be performed in lines handling a wide variety of steel plates without the need to change rolls or switch between modes such as opening and closing the annular recess. [Industrial applicability]
[0030] The method for handling cradle rolls and metal strips according to the present invention prevents damage to the coils regardless of whether or not hoop binding is used, the difference in coil width, the presence or absence of a coating, or the thickness of the sheet metal, thus improving productivity and making it industrially useful. [Explanation of Symbols]
[0031] 1 coil 2 lining 3 Roll Body 4. The convex curve (at the corner of the annular recess) 5 Cradle Roll 6. Annular recess (missing portion) 7. Binding Hoop 8 Adhesive tape
Claims
1. A cradle roll having an annular recess for inserting a bundling hoop for metal strip coils having a thickness in the range of 0.3 to 3.3 mm, The surface of the cradle roll is provided with a lining, The annular recess corresponds to the missing portion of the lining, In a cross-section parallel to the roll axis direction, the cross-sectional shape of the corner from the roll surface of the lining to the annular recess is a convex curve. The target metal strip includes a metal strip that has been coated with an organic film. The hardness of the lining is in the range of 90 to 98 when measured with a Type A durometer compliant with JIS K 6253-3:2012. Cradle Roll.
2. The aforementioned convex curve has a ratio b / a of the length b in the roll axis direction to the length a in the roll radial direction, which is in the range of 1 to 5, and the length a in the roll radial direction is in the range of 0.1 times or more and 0.8 times or less the thickness t of the lining. The cradle roll according to claim 1.
3. Using the cradle roll described in claim 1 or 2, A method for handling metal strips, including end treatment, packaging, and continuous dispensing and winding of the metal strips, Multiple types of end treatments are mixed together. Handling instructions for metal strips.
4. Furthermore, handling metal strips of different widths together, The method for handling a metal strip as described in claim 3.