JPH06142760A - Method for coiling metallic strip - Google Patents

Abstract

PURPOSE:To provide a method, for coiling metallic strip, by which the generation of slackness in the inner winding part of a coil is prevented without lowering productivity. CONSTITUTION:The coiling of a metallic strip by means of a mandrel is performed under the conditions of k-h/r<2>/rho<0.32 (assuming k= yield stress of material (kgf/mm<2>), h= thickness (mm), r= radius of mandrel (mm), rho= specific gravity of material (g/mm<3>)); and then at the time of taking out the coil from the mandrel, the tip end part of the inner winding of the coil is positioned in the area of theta=-30 deg. to 150 deg. against the vertical direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil winding method for a metal strip, which is carried out during a process such as hot rolling or cold rolling.
In particular, it relates to a winding method for preventing loosening of the inner winding portion of the coil.

[0002]

2. Description of the Related Art When manufacturing a thin plate or strip from a slab having a plate thickness of several hundreds of millimeters, steps such as hot rolling, cold rolling, straightening and annealing are performed. The material to be processed is wound into a coil in each step and conveyed to the next step. If there is slack in the winding start part of the coil wound in the previous process, that is, the inner winding part, the wound materials will be separated due to the impact during handling such as transportation or the tension effect during coil rewinding in the next process. Rubbing causes external damage on the surfaces of the two, which deteriorates the surface quality. Further, if the winding portion inside the coil is loose, troubles such as opening of the coil at the time of transportation may occur, or the transportation time may be lengthened and productivity may be reduced. Therefore, when winding the coil in each step, it is necessary to prevent the winding portion in the coil from loosening. Conventionally, the following method has been carried out in order to prevent loosening of the winding portion in the coil. (1) Insert the spool into the winding mandrel before winding the coil. (2) Welding and fixing several turns of the coil edge surface before taking out the coil from the mandrel after winding.

[0003]

However, the method (1) requires time for inserting the spool, and the method (2) requires time for welding, so that the next coil rolling and other processing are awaited. There was a problem that it deteriorated. An object of the present invention is to provide a coil winding method for a metal strip that can prevent loosening in the coil winding portion without lowering productivity.

[0004]

[However, k = material yield stress (kgf / mm ² ) h = plate thickness (mm) r = mandrel radius (mm) ρ = material specific gravity (g / mm ³ ). ]

When the coil 1 is pulled out from the mandrel 3 after that, the tip of the coil inner winding is set to θ with respect to the vertical direction.
= Coil 1 after being positioned in the region of -30 to 150 °
Is configured to be extracted from the mandrel 3. Note that θ in FIG. 1 is the winding direction of the plate 2 (the arrow direction in FIG. 1)
Is positive.

[0005]

When a coil is taken out from the mandrel after winding the coil in a material having a relatively small plate thickness and a relatively small strength, the coil winding portion, which had been constrained by the mandrel until then, is released, and the coil loosens due to the material's own weight. . If the looseness of the winding portion in the coil is considered as the deformation due to the weight of the bending beam, the deformation at the supporting point can be calculated based on the models shown in FIGS. 2 and 3. That is,
In FIG. 2, considering the bending moment at the point P when the point P is the fixed end and the uniformly distributed load w acts on the coil winding portion, the force in the axial direction applied to the minute element is obtained by the following equation (1). be able to. Therefore, the bending moment M ₁ acting on the point P can be expressed by the equation (2).

[0006]

[Equation 1]

[0007]

[Equation 2]

When the deformation at the point P is in the elastic region, the flexure is minute and the problem of loosening of the inner winding does not occur, but it becomes a problem in the plastic region beyond the elastic region. The bending moment M ₂ at the point P in the plastic region is given by the following formula (3) (FIG. 3).
reference). K: Material yield stress (kgf / mm ² ), h: Plate thickness
(mm), r: Mandrel radius (mm), ρ: Material specific gravity (g / mm ³ )
Is. Then, Equation 4 is given from Equations 2 and 3.

[0009]

[Equation 3]

[0010]

[Equation 4]

If the work hardening of the material is ignored and the yield stress k of the material is used as a reference, inward loosening occurs under the condition shown by the following equation (5).

[0012]

[Equation 5]

Although the support point θ is given in the above equation, it is considered that the looseness actually depends on the position of the inner winding tip. However, it is not possible to give a clear relational expression between them. Therefore, the relationship between the occurrence of inner winding looseness and the dimension factor (h / r ² ) and the material factor (k) was experimentally confirmed regardless of the position of the inner winding tip. The result is shown in FIG. 4, and as shown in the figure, k · h / r ² /ρ<0.3
It can be seen that loosening occurs in the range of 2.

Next, the relationship between the value of the end portion of the inner winding and the occurrence state of the inner winding loosening within the range of k · h / r ² /ρ<0.32 was investigated, and the result is shown in FIG. According to the figure, the position value of the inner winding tip is θ = −30 with respect to the vertical direction.
If it is in the range of up to 150 °, no loosening of the inner winding occurs.

As described above, k · h / r ² /ρ<0.3
In case of winding under the condition of No.2, the end of the inner winding should be θ with respect to the vertical direction before pulling out the coil from the mandrel.
= By locating in the range of -30 to 150 °, it is possible to prevent loosening of the inner winding portion. Moreover, the work of positioning the tip of the inner winding in the range of θ = −30 to 150 ° can be performed in an extremely short time as compared with the conventional method of inserting the spool and the method of welding the edge surface, so that the productivity is not reduced. .

[0016]

EXAMPLES Preferred examples of the method of the present invention will be described below. Using aluminum or an aluminum-based alloy as the work material, and in the case of the example of the present invention under the following conditions and the comparative example, the occurrence rate of inner winding looseness due to the position of the inner winding tip portion, and this inner winding looseness The rate of occurrence of external damage during the next rolling was examined. In addition, the loosening rate of inner winding is the rate of occurrence of a coil in which the inner winding portion of the target equipment is loosened and wound up.The rate of external damage is due to loosening of the inner winding generated in the target equipment and Is the rate of occurrence of coils that rub against each other due to the tension effect and cause external damage to the surfaces. Further, the material yield stress k, the plate thickness h, the mandrel radius r, the material specific gravity ρ, etc. of the work material are as follows, and are wound under the condition of k · h / r ² /ρ=0.09 to 0.51. I took it. k: 5.0 to 30.0 (kgf / mm ² ), h: 2.0 to 8.0
(mm), r: 305.0 (mm), ρ: 2.7x
10 ^-3 (g / mm ³ )

The results are shown in Table 1. According to this embodiment, the occurrence rate of loosening of the inner winding was reduced, and as a result, the occurrence of external damage could be prevented.

[0018]

[Table 1]

[0019]

According to the coil winding method of the present invention, it is possible to prevent loosening of the coil winding portion without lowering productivity.

【The invention's effect】 [Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a position of an inner winding tip of a coil in a method of the present invention.

FIG. 2 is a model diagram when the looseness of the inner winding is considered as a deformation due to the weight of the bending beam.

FIG. 3 is a diagram showing a stress distribution during plastic deformation of the curved beam of FIG.

FIG. 4 is a graph showing the relationship between occurrence of inner slack and dimension factor (h / r ² ) and material factor (k).

FIG. 5 is a graph showing the relationship between the value of the end portion of the inner winding and the loosening occurrence state of the inner winding.

[Explanation of symbols]

 1 coil 2 plate 3 mandrel

Claims (1)

[Claims] 1. A coil winding of a metal strip by a mandrel is performed as follows: k · h / r ² /ρ<0.32 [where k = material yield stress (kgf / mm ² ) h = sheet thickness (mm) r = Mandrel radius (mm) ρ = material specific gravity (g / mm ³ ). ], And then pulling out the coil from the mandrel, the tip of the coil inner winding should be θ = − with respect to the vertical direction.
A coil winding method for a metal strip, which is characterized in that it is positioned in a region of 30 to 150 °.