JP2003211219A - Method for coiling cold-rolled steel strip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coiling method of a cold-rolled steel strip for reducing the amount of plastic deformation of a sleeve whose unit price is inexpensive and the handling of which is easily performed and also preventing the edge wave of the inner coiled part of a coil by reducing stress applied to the sleeve by heating the sleeve to specified temperature taking the maximum reachable temperature into consideration before coiling the cold-rolled steel strip. <P>SOLUTION: In the coiling method of the cold-tolled steel strip, before coiling the cold-rolled steel strip 20, the sleeve 11 is heated to the prescribed temperature of 80-200°C and the coiling of the cold-rolled steel strip 20 is started in the state where the temperature of the sleeve 11 reaches the prescribed temperature. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of winding a cold-rolled steel strip, and more particularly, to a method of winding a sleeve before cold-rolling a cold-rolled steel strip. When the rolled steel strip is wound up, it is heated to a predetermined temperature in consideration of the maximum temperature of the steel strip to reduce the stress applied to the sleeve, thereby reducing the amount of plastic deformation of the sleeve and elongating the ear of the coil inner winding part. The present invention relates to a method for winding a cold-rolled steel strip to be prevented. [0002] Generally, at the exit side of a cold rolling mill in a steel strip cold rolling line, a cold rolled steel strip rolled by the cold rolling mill is wound by a winding device. Has become.
Here, the temperature of the steel strip rises due to frictional heating during cold rolling, and the maximum temperature of the steel strip when the cold-rolled steel strip is wound is generally about 120 ° C. The winding device includes a mandrel that is rotatably provided, and a sleeve that is mounted around the mandrel and winds a cold-rolled steel strip. Then, the coil wound by the winding device is removed from the mandrel together with the sleeve by reducing the diameter of the mandrel, mounted on the payoff reel of the next line (for example, a continuous annealing line) together with the sleeve, and discharged. Has become. After the coil is dispensed, the sleeve is mounted again on the mandrel of the winding device on the exit side of the cold rolling mill, and is used repeatedly. Here, when the sleeve is not used, when removing the coil from the mandrel,
A so-called kink problem that the coil does not come out of the mandrel even if the diameter of the mandrel is reduced occurs. A sleeve is used to prevent this kink (to reduce the diameter of the coil). FIG. 3 shows a deformation process of the sleeve 101. The sleeve 101 is formed by welding a steel material, for example, a high tensile strength steel having a yield stress of about 490 Mpa to 690 Mpa into a hollow cylindrical shape, and at normal temperature (for example, 15 ° C.) before use.
In the state (1), as shown in FIG. 3 (A), it has a hollow cylindrical shape having a constant inner diameter in the width direction. And coil 1
In a state in which the temperature is increased to about 120 ° C. by the heat transfer from the cold-rolled steel strip after winding No. 02, the sleeve 101 is subjected to the sum of the stress caused by the tight tightening of the coil 102 and the stress caused by the thermal expansion of the sleeve 101. Although an attempt is made to deform inward, a mandrel (not shown) exists inside the coil 102.
Does not change as shown in FIG. Then, the coil 102 is removed from the mandrel together with the sleeve 101, and the coil 1 is removed.
When 02 is dispensed from the sleeve 101, as shown in FIG. 3 (C), the stress applied to the sleeve 101 causes the sleeve 101 to be plastically deformed into a drum shape whose inner diameter gradually decreases toward the center in the width direction. This plastic deformation occurs remarkably when the sleeve 101 is used repeatedly. FIG. 4 shows a change in the inner diameter of a sleeve having, for example, a high-strength steel having a yield stress of about 490 Mpa to 690 Mpa as the material of the sleeve and having an inner diameter of about 417 mm, an outer diameter of about 441 mm, and a width of about 1050 mm. It is shown. Referring to FIG. 4, the inner diameter of the sleeve is such that when the coil is pulled out of the mandrel at the time of winding (120 ° C.), the sum of the stress due to thermal expansion and the stress due to tight tightening is applied to the sleeve. A maximum strain of 0.37%, which is a sum of a maximum strain of 0.11% caused by stress due to thermal expansion and a maximum strain of 0.26% caused by stress due to tight tightening, is generated in the sleeve. Then, the amount of plastic deformation of the sleeve after dispensing the coil (the amount of plastic deformation of the inner diameter of the sleeve with respect to the inner diameter of the sleeve before use) is 0.16% at the maximum in the sleeve width direction, and the diameter is reduced. [0005] When such plastic deformation occurs in the sleeve, not only is it difficult to attach and detach the mandrel, but also a large ear extension occurs in the inner winding part of the coil using the plastic deformed sleeve, and the coil is removed. This was causing trouble in later lines. Conventionally, measures have been taken to increase the yield stress point of the sleeve material to expand the elastic deformation region, or to increase the thickness of the sleeve to reduce the stress applied to the sleeve. However, when the material of the sleeve is changed, there has been a problem that the sleeve unit price becomes extremely high. On the other hand, when the thickness of the sleeve is increased, the weight of the sleeve is increased, so that handling of the sleeve becomes difficult, and there is a problem that new capital investment is required. In order to solve these problems, for example, Japanese Patent Laid-Open No. 7-2
No. 38323 discloses a winder ring for winding a steel sheet which heats the outer surface of a hollow cylindrical body made of a low alloy steel for a high yield strength structure and then quenches to introduce a circumferential tensile residual stress to the inner surface. A manufacturing method is disclosed. According to this manufacturing method, the compressive stress of the inner peripheral surface due to the tightening force of the steel sheet is offset by the residual tensile stress of the inner surface introduced in advance, and the effect is caused by the tightening force of the steel sheet. Permanent deformation can be suppressed and alleviated. However, in the method of manufacturing a winder ring for winding a steel sheet disclosed in Japanese Patent Application Laid-Open No. 7-238323, the plastic deformation of the winder ring (sleeve) is not described. Although the amount can be suppressed, in the production of winder ring, after performing a heat treatment heat treatment to impart the required mechanical properties to the hollow cylindrical body made of low-alloy steel for high-strength structures in accordance with a conventional method,
Further, it is necessary to perform a heat treatment for introducing a tensile residual stress, which increases the manufacturing cost of the winder ring,
The problem of a very high winder ring unit price still remained. SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to precede a cold-rolled steel strip in which the unit price of the sleeve is low and the handling thereof can be easily performed. To reduce the stress on the sleeve by heating the sleeve to a predetermined temperature that takes into account the highest temperature when winding the steel strip, thereby reducing the amount of plastic deformation of the sleeve and preventing the ear from elongating the inner winding of the coil. To provide a method for winding a cold-rolled steel strip. [0010] In order to solve the above-mentioned problems, a method for winding a cold-rolled steel strip according to the present invention comprises the steps of: The method for winding a cold-rolled steel strip according to claim 1, wherein the cold-rolled steel strip is wound by a winding device including a mandrel and a sleeve mounted on the mandrel and winding the cold-rolled steel strip. Prior to winding the cold rolled steel strip, the sleeve is
The method is characterized in that the cold-rolled steel strip is started to be wound in a state where the sleeve is heated to a predetermined temperature of 200 ° C. or lower and the sleeve reaches the predetermined temperature. According to this winding method, before winding the cold-rolled steel strip, the sleeve is heated to a predetermined temperature of 80 ° C. or more and 200 ° C. or less. Since the winding of the rolled steel strip is started, before the winding of the cold-rolled steel strip, the sleeve is kept at 80 ° C.
Heated to a predetermined temperature of not more than ° C. Since the maximum temperature of the steel strip when winding the cold-rolled steel strip is about 120 ° C,
When winding a cold-rolled steel strip, stress due to thermal expansion of the sleeve is alleviated for the sleeve, and only stress due to tight tightening of the coil acts on the sleeve, and the stress applied to the sleeve is reduced. Therefore, the amount of plastic deformation of the sleeve that occurs when the coil is paid out is reduced. In order to reduce the amount of plastic deformation of the sleeve, it is not necessary to perform a heat treatment for introducing a tensile residual stress when manufacturing the sleeve, and the manufacturing cost of the sleeve can be reduced. The reason why the heating temperature of the sleeve is set to a predetermined temperature of 80 ° C. or higher is that at a temperature lower than 80 ° C., the amount of relaxation of the stress corresponding to the strain due to the thermal expansion of the sleeve becomes insufficient. is there. On the other hand, the reason why the heating temperature of the sleeve is set to the predetermined temperature of 200 ° C. or less is that at a temperature higher than 200 ° C., the rolling oil adhering to the cold-rolled steel strip burns out and degreasing is performed in the line after winding the steel strip. This is because when it is performed, the degreasing becomes defective. Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a cold rolling line to which a method for winding a cold-rolled steel strip according to the present invention is applied. In the cold rolling line 1 in FIG. 1, the cold-rolled steel strip 20 rolled by the cold rolling mill 2 passes through the deflector roll 3, the tension meter 4, the pinch roll 5, the output shear 6, and the deflector roll 7. Then, it is wound into a coil 21 by the winding device 9. Note that reference numeral 8 is
This is a guide for guiding the cold-rolled steel strip 20 whose direction is changed by the deflector roll 7. The winding device 9 includes a mandrel 10 rotatably provided, a sleeve 11 mounted around the mandrel 10 and winding up the cold-rolled steel strip 20, and a cold-rolled steel strip 20. And a pressing roll 12 for holding several windings of the initial winding while guiding the winding between the leading end and the sleeve 11. The coil 21 wound by the winding device 9 is detached from the mandrel 10 together with the sleeve 11 by reducing the diameter of the mandrel 10,
It is mounted on the pay-off reel of the next line (for example, a continuous annealing line) together with the sleeve 11, and is paid out. The sleeve 11 is mounted on the mandrel 10 again after the coil 21 is dispensed, and is used repeatedly. Here, the cold-rolled steel strip 2 by the winding device 9 is used.
0 will be described in detail.
Prior to winding the cold-rolled steel strip 20, the sleeve 11 is heated to a predetermined temperature of 80 ° C. or more and 200 ° C. or less, and cold-rolled while the sleeve 11 has reached the predetermined temperature. The winding of the steel strip 20 is started. Specifically, a steel material, for example, having a yield stress of 490 Mpa
A sleeve 11 manufactured by welding high-tensile steel of about 690 Mpa to a hollow cylindrical shape is heated to a predetermined temperature of 80 ° C. or more and 200 ° C. or less in advance, and then attached to the mandrel 10. The winding of the cold-rolled steel strip 20 is started while the predetermined temperature is maintained, or the mandrel 10 is wound while the sleeve 11 is kept at a normal temperature.
After that, the sleeve 11 is heated to a predetermined temperature of 80 ° C. or more and 200 ° C. or less, and winding of the cold-rolled steel strip 20 is started when the sleeve 11 has reached the predetermined temperature. The heating method of the sleeve 11 may be, for example, heating by radiant heat or heating by steam. According to this winding method, the cold-rolled steel strip 2
Before winding 0, the sleeve 11 is at
It is heated to a predetermined temperature of 0 ° C. or less. Since the maximum temperature of the steel strip 20 when the cold-rolled steel strip 20 is wound is about 120 ° C., when the cold-rolled steel strip 20 is wound, the conventional sleeve 11 is The stress caused by the thermal expansion of the sleeve 11 caused by heating by the cold-rolled steel strip 20 to be wound is reduced, and only the stress caused by tightening of the coil 20 acts on the sleeve 11, and the stress applied to the sleeve 11 is small. Become. Therefore, the amount of plastic deformation of the sleeve 11 that occurs when the coil 20 is paid out is reduced. Therefore, the operation of attaching and detaching the sleeve 11 to and from the mandrel 10 can be easily performed, and the coil 2
It is possible to prevent a large ear extension from occurring in the inner winding part. Therefore, in order to reduce the amount of plastic deformation of the sleeve 11, it is not necessary to perform a heat treatment for introducing the residual tensile stress as described above, for example, when manufacturing the sleeve 11. It can be. Further, since it is not necessary to make the plate thickness of the sleeve 11 unnecessarily thick, handling of the sleeve 11 can be easily performed. The reason why the heating temperature of the sleeve 11 is set to the predetermined temperature of 80 ° C. or higher is that at a temperature lower than 80 ° C., the amount of relaxation of the stress due to the thermal expansion of the sleeve 11 becomes insufficient. More preferably, the heating temperature of the sleeve 11 is 100 ° C. or higher. On the other hand, the reason why the heating temperature of the sleeve 11 is set to the predetermined temperature of 200 ° C. or lower is that at a temperature higher than 200 ° C., the rolling oil attached to the cold-rolled steel strip 20 burns, and the line after winding the steel strip is removed. This is because when degreasing is performed, the degreasing becomes defective.
However, since the maximum temperature of the steel strip 20 when the cold-rolled steel strip 20 is wound is about 120 ° C., the heating temperature of the sleeve 11 is set to 130 ° C. or lower, which is near the maximum temperature of the steel strip 20. Is preferred. EXAMPLE In order to verify the effects of the present invention, high-strength steel having a yield stress of about 490 Mpa to 690 Mpa was used as the material of the sleeve, and the inner diameter was about 417 mm and the outer diameter was about 441.
mm and a width of about 1050 mm
The change in the inner diameter of the sleeve between the case where the coil was wound with the sleeve heated to 20 ° C. (Example) and the case where the coil was wound without heating the sleeve (Comparative Example) was measured. The result is shown in FIG. Referring to FIG. 2, when the coil is wound (at a temperature of 120 ° C.) (with the mandrel removed), the inner diameter of the sleeve of the embodiment is such that the stress due to thermal expansion is alleviated, and only the stress due to tight tightening is obtained. Is applied to the sleeve, so that a maximum strain of 0.26% is generated in the sleeve in the coil width direction due to stress caused by tight tightening. On the other hand, the inner diameter of the sleeve of the comparative example is such that when the coil is wound (at 120 ° C.) (in a state where it is pulled out of the mandrel), the sum of the stress due to thermal expansion and the stress due to tight tightening is applied to the sleeve. Maximum strain 0.1 due to stress due to thermal expansion in the width direction
1% and maximum strain of 0.26 due to stress due to tight tightening
The maximum strain of 0.37%, which is the sum of% and the maximum, is generated in the sleeve. Therefore, in the embodiment, the maximum strain of the sleeve at the time of winding the coil (120 ° C.) is smaller than that of the comparative example by 0.11%. For this reason, the amount of plastic deformation of the sleeve after dispensing the coil can be reduced. According to the method for winding a cold-rolled steel strip according to the present invention, the maximum temperature of the steel strip when winding the cold-rolled steel strip reaches about 120 ° C. Prior to winding the cold-rolled steel strip, the sleeve is heated to a predetermined temperature of 80 ° C. or more and 200 ° C. or less, and winding of the cold-rolled steel strip is started in a state where the sleeve has reached the predetermined temperature. Before winding the cold-rolled steel strip, the sleeve is kept at 80 ° C. or higher and 200 ° C.
Heated to a predetermined temperature of ℃ or less, the stress caused by the thermal expansion of the sleeve, which was conventionally caused by heat transfer from the steel strip, is relaxed,
Only the stress caused by tight tightening of the coil acts on the sleeve, and the stress applied to the sleeve is reduced. For this reason, the amount of plastic deformation of the sleeve that occurs when the coil is paid out is reduced, and the operation of attaching and detaching the sleeve to and from the mandrel can be easily performed, and it is possible to prevent a large ear extension from occurring in the inner winding portion of the coil. . Therefore, in order to reduce the amount of plastic deformation of the sleeve, it is not necessary to perform a heat treatment for introducing a tensile residual stress in manufacturing the sleeve, and the manufacturing cost of the sleeve can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of a cold rolling line to which a method for winding a cold-rolled steel strip according to the present invention is applied. FIG. 2 shows a measurement result of a change in sleeve inner diameter when a coil is wound with a sleeve heated to 120 ° C. in advance (Example) and when a coil is wound without a sleeve heated in advance (Comparative Example). FIG. FIG. 3 is a schematic explanatory view showing a deformation process of a sleeve. FIG. 4 shows a yield stress of 490 Mpa as a material of the sleeve.
High-strength steel of about 690 Mpa and an inner diameter of about 417
7 is a graph showing a measurement result of a change in an inner diameter of a sleeve having an outer diameter of about 441 mm and a width of about 1050 mm. [Description of Signs] 1 Cold rolling line 2 Cold rolling mill 3 Deflector roll 4 Tension meter 5 Pinch roll 6 Outlet shear 7 Deflector roll 8 Guide 9 Winding device 10 Mandrel 11 Sleeve 12 Pressing roll 20 Cold rolled steel strip 21 coils

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Hideo Kijima             1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba             Iron Research Institute (72) Inventor Motomi Imamura             1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba             Inside the Iron Corporation Chiba Works F term (reference) 3F055 AA09 BA25 EA02                 4E002 BD03 BD08                 4E026 BA04 FA11

Claims (1)

Claims 1. At the outlet side of a cold rolling mill, a cold rolled steel strip rolled by the cold rolling mill is provided with a mandrel, and the cold rolled steel strip mounted on the mandrel. A method for winding a cold-rolled steel strip with a winding device provided with a sleeve for winding the cold-rolled steel strip, wherein, before winding the cold-rolled steel strip, the sleeve is heated to a predetermined temperature of 80 ° C or more and 200 ° C or less. And winding the cold-rolled steel strip in a state where the sleeve has reached the predetermined temperature.