JP2000042881A - Polishing method and device for thin steel belt end surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably restrain the generation of a small hole in the welding part even if a small diameter thin steel pipe is manufactured by welding and forge welding by forming a coil by winding a narrow thin steel belt, and polishing the end surface of the coil by a stainless steel brush homogeneous or almost close to the coil. SOLUTION: A coil support means 7 is arranged to rotate a coil 11 of a narrow thin steel belt 1 obtained by cutting a wide thin steel belt in a plurality by horizontally supporting a shaft. A rotary brush 5 required for polishing is a disk-shaped rotary structure, a material requires hardness and resiliency of a certain degree, and is desirably almost homogeneous to a material of a polishing object steel belt, but a stainless steel wire is normally excellently used. Next, the rotary brush 5 is contacted with both end surfaces of the coil 11, and the brush 5 is arranged on a carriage 10 to be moved to be sent out along a rail 9. The brush 5 is rectilinearly moved up to an inside diameter from an outside diameter of the coil 11 by this sending-out to polish one side end surface of the coil 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for polishing an end face of a thin steel strip. More specifically, the present invention relates to a method for polishing a widthwise end face of a narrow steel strip obtained by cutting a wide steel strip into a plurality of strips. This is a technology to reliably polish without trouble.

[0002]

2. Description of the Related Art In order to manufacture a small-diameter (for example, an outer diameter of about 20 to 30 mmφ) and thin-wall (for example, about 0.2 mm) welded steel pipe, first, a wide steel strip of about 1200 mm is formed into a plurality of strips. Cut into narrow steel strips. And
After forming the narrow steel strip into a tubular shape, the butted portions are welded to form a steel pipe.

At this time, the butted portions correspond to both end faces in the width direction of the steel strip. Generally, in the case of a thick steel strip, both end faces are polished by a kind of grinder such as an edge mirror 2 while the steel strip 1 is still running on the line after cutting, as shown in FIG. , May be shaped.

However, in such a conventional polishing method, when the edge mirror 2 is strongly pressed against the end face of the steel strip, the end of the steel strip 1 is bent due to the thin wall, so that not only the polishing cannot be performed smoothly, but also the polishing condition is reduced. It is uneven. As a result, when the end faces of the polished steel strip 1 are not uniform, holes are opened at the time of welding, or the steel pipe after welding is rolled through a die,
When processing into a so-called flexible steel pipe, a small-diameter hole is often opened in the welded portion. At present, this hole has been found by nondestructive inspection (eddy current inspection), airtightness test and the like.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention provides a thin steel which can reliably suppress the formation of small holes in a welded portion even when a small-diameter and thin-walled steel pipe is manufactured by welding or forging. It is an object of the present invention to provide a method and an apparatus for polishing a band.

[0006]

In order to achieve the above object, the inventor investigated the end face of the thin steel strip after cutting. As a result, the end face of the thin steel plate in which the small holes are formed is formed by the cut surface by the cutting tool and the fracture surface, and the fracture surface 3 is about 0.02 mm deeper than the cut surface 4 as shown in FIG. It turned out that it was dented. When the relationship between this fractured surface and the generation of small holes in the welded portion was investigated, the small holes were found to have a large change in the ratio between the fractured surface 3 and the cut surface 4 at the end face of the continuous steel strip. It was confirmed that it had occurred. The inventor of the present invention has worked diligently to eliminate the dents formed on the end face without causing any trouble, and has completed the present invention.

That is, the present invention relates to a method for polishing a widthwise end face of a narrow thin steel strip obtained by cutting a wide thin steel strip into a plurality of strips. And polishing the end face of the coil with a stainless steel brush of the same quality or almost similar to that of the coil.

[0008] The present invention is also a method for polishing the end face of a thin steel strip, characterized in that the thickness of the narrow thin steel strip is 0.1 to 1.0 mm.

Furthermore, the present invention provides a polishing apparatus for an end face in the width direction of a narrow thin steel strip obtained by cutting a wide thin steel strip into a plurality of strips, wherein the coil of the narrow thin steel strip is formed by an axis. Coil support means for horizontally supporting and rotating, a disk-shaped rotary brush for polishing the end face of the coil, and brush feed means for bringing the rotary brush into contact with the end face of the coil and moving on the end face. A polishing apparatus for polishing an end face of a thin steel strip, comprising:

The present invention is also an apparatus for polishing the end face of a thin steel strip, wherein the rotating brush is made of stainless steel.

According to the present invention, the end face of a steel strip used for producing a small-diameter and thin-walled steel pipe by welding or forging can be reliably polished without any trouble. As a result, generation of small holes in the welded portion of the obtained steel pipe can be more reliably suppressed than before.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

The polishing apparatus according to the present invention has a configuration as shown in FIG. That is, first, there is provided the coil supporting means 7 for supporting and rotating the coil 11 of the narrow thin steel strip 1 obtained by cutting the wide thin steel strip into a plurality of strips while keeping the axis horizontal. The coil supporting means 7 may be separately provided only for polishing the end face of the steel strip 1, but usually an existing uncoiler for rewinding the coil 11 can be used.

The rotating brush 5 required for polishing has a disk shape.
Any structure may be used as long as it has a rotating structure. For example, a member obtained by bundling linear members having a length of about 100 mm in a radial manner can be used. The material is required to have a certain degree of hardness and elasticity. According to the trials of the inventors, it is preferable that the material is substantially the same as the material of the steel strip to be polished, but usually, stainless steel wire is preferably used. The end face of the coil 11 to be polished is not so aligned with the end portion of the steel strip 1 when the coil 11 is wound, and is in a so-called “stereco” state. However, such a brush 5 made of stainless steel is well adapted to the unevenness of the end face and can be polished without any trouble.
The degree of polishing is about 0.02 mm because the above-mentioned cut surface may be adjusted so as to match the rupture surface. The rotating mechanism of the brush 5 may use a normal motor 6.

Next, the rotating brush 5 needs to be moved by contacting both end faces of the coil 11. Therefore, in the present invention, as shown in FIG. 1, the brush 5 is installed on the carriage 10 and is sent out along the rail 9. For this feeding, it is sufficient that the brush 5 can linearly move the distance from the outer diameter to the inner diameter of the coil 11. This is because the end face on one side of the coil 11 can be polished by such movement.

The two rotating brushes 5 according to the present invention may be installed on both end faces of the coil 11.
Can be replaced by, for example, a crane (not shown)
One is enough. In the present invention, the thickness of the thin steel strip 1 is preferably 0.1 to 1.0 mm. The reason is 0.1
This is because steel pipes of less than 1.0 mm
If it exceeds m, there is no polishing effect.

[0017]

EXAMPLE A steel strip 1 having a width of 76 mm and a thickness of 0.2 mm was wound into a coil 11 having an outer diameter of 1200 mm and an inner diameter of 500 mm. The coil 11 was set in the polishing apparatus according to the present invention shown in FIG. 1, and the end face of the coil 11 was polished. After 60 minutes, replace the direction of the coil 11 using a crane,
Another surface was polished for the same time.

Next, the steel strip 1 after polishing was transported to a welded steel pipe factory and formed into an annular shape. Then, connect the joint with TIG
And the above-mentioned inspection of the weld was performed. As a result, in the case of the conventional steel sheet with a defective end portion, holes were formed once every 100 m. However, when the polishing method according to the present invention was employed, small holes were generated even at 380 m or more. Did not.

[0019]

As described above, according to the present invention, the end face of a steel strip used for manufacturing a small-diameter and thin-walled steel pipe by welding or forging can be surely polished without any trouble. As a result, generation of small holes in the welded portion of the obtained steel pipe can be more reliably suppressed than before.

[Brief description of the drawings]

FIG. 1 is a view showing an apparatus for polishing a thin steel strip end face according to the present invention, wherein (a) is a plan view and (b) is a side view.

FIG. 2 is a perspective view showing a conventional method for polishing the end face of a thin steel strip.

FIG. 3 is a view showing a state of an end face of a thin steel strip cut by a slitter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel strip 2 Edge mirror 3 Breaking surface 4 Cutting surface 5 Rotary brush (brush) 6 Motor 7 Coil support means 8 Feeding means 9 Rail 10 Dolly 11 Coil

Claims (4)

[Claims] 1. A method for polishing a widthwise end surface of a narrow thin steel strip obtained by cutting a wide thin steel strip into a plurality of sheets, wherein the narrow thin steel strip is wound to form a coil, A method for polishing the end face of a thin steel strip, wherein the end face of the coil is polished with a stainless steel brush. 2. The thin steel strip having a thickness of 0.1 to 1.
2. The method for polishing the end face of a thin steel strip according to claim 1, wherein the thickness is 0 mm. 3. A polishing apparatus for a width direction end face of a narrow thin steel strip obtained by cutting a wide thin steel strip into a plurality of strips, comprising: Coil supporting means for supporting and rotating, a disk-shaped rotary brush for polishing the end face of the coil, and brush feed means for bringing the rotary brush into contact with the end face of the coil and moving on the end face. A polishing apparatus for polishing a thin steel strip end face. 4. A polishing apparatus for polishing the end face of a thin steel strip according to claim 3, wherein said rotary brush is made of stainless steel.