JP7736051B2 - Metal strip winding segment, mandrel, winding device, process line, metal strip winding method, and high-tensile steel sheet manufacturing method - Google Patents

Description

The present invention relates to a metal strip winding segment, a mandrel, a winding device, a process line, a metal strip winding method, and a method for manufacturing high-tensile steel sheets, for winding metal strips such as high-tensile steel sheets into coils.

In recent years, there has been growing demand for high-tensile steel sheets for use in automobile frames in order to reduce the weight of automobile bodies and improve collision safety. The production of metal strips, such as high-tensile steel sheets, involves heat treatment in continuous annealing equipment to obtain the product's mechanical properties. After heat treatment, the metal strip is then wound onto a reel in a winding device to form a coil.

The winding device has a mandrel shaft that rotates for winding, steel segments that are arranged around the mandrel shaft, and sleeves that are attached to the outside of the segments.

High-tensile steel sheets with a tensile strength of 1,180 MPa or more are prone to inner diameter collapse after being coiled if the tension applied during winding after heat treatment is insufficient. To prevent inner diameter collapse, a method has been proposed for increasing the tension applied to the metal strip during winding (Patent Document 1).

Japanese Patent Application Publication No. 11-267746

However, the method described in Patent Document 1 (increasing the tension of the metal strip during winding) occasionally causes slippage between the segment and the sleeve, resulting in winding defects. These winding defects then lead to problems such as the need for rewinding work and reduced product yield.

The present invention was made in consideration of these circumstances, and aims to provide a metal strip winding segment, mandrel, winding device, process line, metal strip winding method, and high-tensile steel sheet manufacturing method that can suppress slippage between the segment and sleeve when winding a metal strip, thereby preventing poor metal strip winding, the need for rewinding, and reduced product yield.

The gist and configuration of the present invention to solve the above problems are as follows.
[1] A metal strip winding segment that is provided around a mandrel shaft that rotates when winding a metal strip, and has a sleeve attached to the outside that contacts the metal strip, wherein the arithmetic mean roughness Ra of the contact surface with the sleeve is 3.2 μm or more and 12.5 μm or less.
[2] A mandrel comprising the metal strip winding segment according to [1] and the mandrel shaft.
[3] A winding device having the mandrel according to [2].
[4] A process line having the winding device according to [3].
[5] A method for winding a metal strip, comprising winding the metal strip using the winding device described in [3].
[6] A method for manufacturing a high-tensile steel plate by winding a high-tensile steel plate using the metal strip winding method described in [5].

This invention reduces slippage between the segment and sleeve when winding the metal strip, making it possible to prevent poor winding of the metal strip, the need for rewinding, and reduced product yield.

FIG. 2 is a perspective schematic view showing an example of a winding device. FIG. 2 is a schematic side view showing an example of a mandrel and a sleeve.

The present invention will be described below through an embodiment of the present invention. Here, the configuration of a winding device 10, which is one embodiment of the present invention, will be described with reference to Figure 1. Figure 1 shows a schematic perspective view of the winding device 10.

As shown in Figure 1, the winding device 10 is installed in a process line for heat treatment in a continuous annealing facility. The winding device 10 has a mandrel 3, pinch rolls 4, and a tension adjustment device 7. The metal strip S is transported in the sheet threading direction (arrow A in the figure) as the mandrel 3 rotates. The metal strip S is wound around the mandrel 3 to form a coil. As the metal strip S is transported in the sheet threading direction A, the direction of transport is changed toward the mandrel 3 where it is wound via the pinch rolls 4 installed midway.

While the metal strip S is being transported, the tension (t) of the metal sheet S increases or decreases by increasing or decreasing the rotational speed of the mandrel 3 (mandrel shaft 1). In other words, the tension of the metal strip S can be increased by increasing the rotational speed of the mandrel 3 (mandrel shaft 1). For this reason, the tension adjustment device 7 sends a control signal to the mandrel 3 (mandrel shaft 1) to control the rotational speed, and adjusts the tension of the metal strip S during winding.

Next, the configuration of the mandrel 3 will be described using Figure 2. As shown in Figure 2, the mandrel 3 has a mandrel shaft 1 and segments 2. The segments 2 are arranged around the mandrel shaft 1. The mandrel shaft 1 rotates upon receiving a rotational driving force from a rotational driving source (not shown) such as a motor. The segments 2 are divided into multiple segments and can expand and contract. When winding the metal strip S, the segments 2 expand to relatively fix the sleeve 5, and can contract when the sleeve 5 is pulled out after winding the metal strip S. The segments 2 correspond to the metal strip winding segments in this invention.

The sleeve 5 is attached to the outside of the segment 2. The sleeve 5 is made of an elastic material such as rubber. There are several types of sleeve 5 with different thicknesses. Therefore, by replacing the sleeve 5, the inner diameter of the coil of metal strip S after winding can be changed.

When the metal strip S is wound, the segments 2 and sleeve 5 rotate simultaneously as the mandrel shaft 1 rotates, wrapping the metal strip S around the outside of the sleeve 5 and forming a coil. The contact surface of the segments 2 that comes into contact with the sleeve 5 is processed using shot blasting (shot peening) or electrical discharge machining to achieve an arithmetic mean roughness Ra of 3.2 μm or greater. This increases the friction between the segments 2 and the sleeve 5 and reduces slippage between the segments 2 and the sleeve 5. An arithmetic mean roughness Ra of 4.0 μm or greater is preferable. While a higher arithmetic mean roughness Ra can more effectively reduce slippage, a value large enough to prevent interference when unwinding the sleeve 5 from the segments 2 after winding the metal strip S is preferred. For example, an arithmetic mean roughness Ra of 12.5 μm or less allows for smooth unwinding of the sleeve 5 from the segments 2. An arithmetic mean roughness Ra of 10.0 μm or less is more preferable.

With the above configuration, the winding device 10 may be used to perform a method for winding a metal strip S. Furthermore, when implementing the method for winding a metal strip S using the winding device 10, a high-tensile steel plate may be used as the metal strip S. Furthermore, the method for winding a metal strip S may be used to perform a method for manufacturing a high-tensile steel plate by winding the high-tensile steel plate.

Next, Table 1 shows the results of winding a metal strip S having a thickness of 1.8 to 2.3 mm and a tensile strength TS of 1180 MPa or more using the winding device 10 shown in Figure 1. In Table 1, Examples 1 to 6 of the present invention show results when the arithmetic mean roughness Ra of segment 2 was set to 3.2 μm or more and 12.5 μm or less, while Comparative Examples 1 to 6 show results when the arithmetic mean roughness Ra of segment 2 was set to 0.8 μm, 2.0 μm, and 13.0 μm. When winding the metal strip S, the tension (t) was calculated based on the torque of the motor rotating the mandrel shaft 1 and the outer diameter of the coil. The tension (t) was adjusted (controlled) by controlling the magnetic flux of the motor rotating the mandrel shaft 1 to correspond to the conveying speed (line speed) of the metal sheet S and the coil diameter.

As shown in Table 1, in Comparative Examples 1 to 4, when the winding tension was set to 4.3 to 6.0 t and the arithmetic mean roughness Ra of segment 2 was set to 0.8 μm or 2.0 μm, slippage occurred. Furthermore, in Comparative Examples 5 and 6, when the winding tension was set to 4.3 to 6.0 t and the arithmetic mean roughness Ra of segment 2 was set to 13.0 μm, slippage was avoided, but problems occurred when pulling out sleeve 5 from segment 2.

On the other hand, as can be seen from the results of invention examples 1 to 6, when the winding tension was set to 4.3 to 6.0 t and the arithmetic mean roughness Ra of segment 2 was set to 3.2 μm, 5.0 μm, or 12.5 μm, slippage was avoided and problems when pulling out sleeve 5 from segment 2 were also avoided. In other words, it was confirmed that slippage was suppressed by setting the tension of metal strip S to a value exceeding 4.0 (t) when winding metal strip S and setting the arithmetic mean roughness Ra of segment 2 to 3.2 μm or more and 12.5 μm or less.

REFERENCE SIGNS LIST 1 Mandrel shaft 2 Segment 3 Mandrel 4 Pinch roll 5 Sleeve 7 Tension adjusting device 10 Winding device A Strip threading direction

Claims (6)

A segment for winding a high-tensile steel plate, the segment being provided around a mandrel shaft that rotates when winding a high-tensile steel plate having a tensile strength of 1180 MPa or more , and having a rubber sleeve attached to the outside that comes into contact with the high-tensile steel plate,
The segment for winding high-tensile steel sheet has an arithmetic mean roughness Ra of the contact surface with the rubber sleeve of 3.2 μm or more and 12.5 μm or less. A mandrel comprising the high-tensile steel sheet winding segment according to claim 1 and the mandrel shaft. A winding device having the mandrel described in claim 2. A process line having the winding device described in claim 3. A method for winding a high-tensile steel plate , comprising winding the high-tensile steel plate using the winding device according to claim 3. A method for producing a high-tensile steel plate , comprising winding a high-tensile steel plate by the method for winding a high-tensile steel plate according to claim 5.