JPS6289505A - Dull roll - Google Patents

Abstract

PURPOSE:To produce a dull roll having excellent characteristics by rolling the roll and spraying grit consisting of 'Alundum(R)' abrasive grains at a specific angle to the roll surface in the stage of producing the dull roll for cold rolling of a steel sheet. CONSTITUTION:The dull roll of which the surface has the prescribed roughness is used for the work roll of the final stand to roughen the surface of the steel sheet in the stage of cold rolling the steel sheet with a cold tandem rolling mill. Seizure is prevented and the elongation characteristic of the cold rolled steel sheet is improved in the stage of annealing the steel sheet after coiling. The work roll 7 for cold rolling is imposed on spinner rolls 6, 6 in a cabinet 8 and while the roll is rotated, the grit consisting of the 'Alundum(R)' abrasive grains is sprayed by compressed air from 50-100mm distance at 30-40 angle A with normal 7a to the roll from a spraying nozzle 12 to form dull grains 3 having shape directivity on the surface 2 of the roll 1 in the stage of producing the above-mentioned roll. The dull roll is thus formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a dull roll having dull grooves formed on its outer peripheral surface, and for example, relates to a dull roll used as a work roll for the final stand of a cold rolling mill. .

As is well known in the art, cold-rolled steel products are generally produced by descaling hot-rolled steel products, followed by cold rolling such as cold tandem rolling, and then annealing, followed by shape correction and stretcher strain prevention. Furthermore, temper rolling is performed to obtain predetermined mechanical properties.

In the case of common steel types, the rolled material is wound up after cold rolling, made into a coil shape, and then directly charged into, for example, a batch furnace for annealing. Bride rolls whose surfaces are ground with a grindstone are used as work rolls for rolling, but when such rolls are used as work rolls for the final stand of cold rolling, the rolled material made into a coil is annealed. In order to prevent such seizure, the surface of the roll is roughened to a predetermined roughness of, for example, 2.5 JJmR as the final stand work roll.
A dull roll as shown in a) is used. A dull roll is formed by projecting a grid, for example, a steel grid, onto the roll's outer circumferential surface to form a dull pattern, so that the roll's outer circumferential surface has a satin texture and has a predetermined roughness.

In addition, dull rolls with a predetermined roughness on the outer surface are used to improve paint smuggling during painting work, which is a post-process of cold rolling and temper rolling, and to reduce die wear during press working. There is.

In addition to the dull roll, in order to achieve the above-mentioned objectives, unlike normal bride rolls, the outer circumferential surface of the roll is ground with a grindstone with a large roughness to a predetermined roughness, that is, the outer circumferential surface is scratched. A roll called a scratch roll is used.

Problems with the conventional technology However, in the conventional dull roll, the dull stitches are formed by projecting a grid perpendicularly to the outer peripheral surface of the dull roll, so the dull stitches do not have any directionality in shape. When rolling using a roll, the elongation properties of the rolled material are not good, and the properties are about 30% poorer than when the above-mentioned bride roll is used.

On the other hand, when rolling using a bride roll, the elongation properties of the rolled material are good. However, the surface roughness of the bride roll surface is generally 2.0 Ra or less, and it is not effective in preventing seizure between rolled materials during annealing or improving paint adhesion in post-process painting work. This is insufficient, and the incidence of adhesion of the steel strip during annealing is high. The roll surface roughness, which has a great effect on the anti-seizure effect, depends on the roughness of the grinding wheel.For scratch rolls that are ground with a grindstone with a large roughness to form scratches, In order to obtain a predetermined roughness of the outer peripheral surface of the dull roll, it is necessary to use a grindstone with an average grain size of 1200 um. Also, the density of the scratches formed in this way is the dull roll density (22500/c/
), which is extremely small at about 1/10 (2000/crl) compared to 2000/crl.Therefore, there is a problem that the rolled material is easily crushed early due to wear and compression, resulting in a short roll life. The scratch density depends on the diameter of the grinding wheel, and it is not easy to increase the scratch density to a desired degree by changing the diameter of the grinding wheel, and it is also economically disadvantageous. In other words, it is extremely difficult to improve both the roughness and density of scratch rolls.
There has not been a roll that has sufficient effects such as preventing seizure of rolled materials and has excellent life characteristics of the roll itself.

The present inventors thought that it would be more appropriate to improve the dullness of a dull roll than to improve the scratch roll to increase the predetermined roughness of the roll surface by 1q, and thus came up with the present invention.

The basic/main purpose of this invention is to solve the above-mentioned problems, and is a dull roll that fully obtains effects such as preventing seizure of rolled materials, improves the elongation characteristics of rolled materials, and roughly improves roll life characteristics. It provides:

Means for solving the problem, that is, the present invention is a dull roll having dowels formed on the outer peripheral surface, characterized in that the dowels have shape directionality in the circumferential direction of the roll.

Function: The dull roll of the present invention has a dull pattern with shape directionality in the circumferential direction of the roll.

Here, having shape directionality in the circumferential direction of the roll means that the length in the roll circumferential direction of each recess (double) formed by projection of the grid is longer than the width in the direction parallel to the roll axis. means. Such dull rolls can have a much larger surface roughness and a larger density of surface recesses than scratch rolls, so they are used as work rolls during rolling, especially as work rolls in the final stand of the rolling mill. If used, seizure of the rolled material can be sufficiently prevented, and the dowels are aligned in the circumferential direction of the roll (
Therefore, since it has shape directionality in the rolling direction), it has the effect of improving the elongation characteristics of the rolled material, roughly improving the life characteristics of the roll itself, and extending its life.

Specific explanation for carrying out the invention As a method for forming dull stitches with shape directionality on the outer circumferential surface of a dull roll, for example, the outer circumferential surface of the roll is formed at a projection angle A that is inclined at a predetermined angle with respect to the normal line of the outer circumferential surface of the roll. There is a method to form a dull mesh by projecting a grid onto the grid. Workpiece rolls for cold rolling generally have a high hardness of 95 Shore hardness, so as mentioned above, the desired surface roughness and dull density can be obtained by projecting from an oblique direction to the normal to the roll surface. In order to obtain this, it is necessary to use a highly hard and fine-grained grid. Therefore, for work rolls for cold rolling, Alundum (AJ2203), which has 2.5 times the indentation hardness and about 1/10 the grain size, is used as a steel grid (HV = 1000, grain size = 700 mm). ) Abrasive grain (t-
1v=2500, particle size 70umφ) is preferably used. When using such a fine and lightweight grid, if it is projected onto the outer peripheral surface of the roll using the conventional shot blasting method, there is a risk that it will be scattered onto the outer peripheral surface of the roll due to air resistance. Therefore, when using fine and lightweight abrasive grains, such as the above-mentioned Alundum abrasive grains, it is best to mix them with compressed abrasive grains in order to eliminate air resistance, and manufacture them using the air blast method in which the mixture is sprayed from the tip of a nozzle onto the outer peripheral surface of the roll. preferable.

FIG. 5 is an example of a device for forming a dull pattern on the outer peripheral surface of a roll by projecting a grid using an air blast method.
The air blast device 1 is not shown.

Two spinner rolls 6.6 are rotatably attached to a cart 5 that is movable perpendicularly to the figure, and a roll 7 forming a dull stitch is placed between the spinner rolls 6.6. Said truck 5, spinner roll 6.6 and roll 7
is covered by cabinet 8. A grid storage tank 9 is disposed outside the cabinet 8, and the tank 9 is connected to a mixing valve 10 for mixing compressed air and transferring the grid, and the mixing valve 10 connects a transfer pipe 11. It is connected to a spray nozzle 12 disposed within the cabinet 8 through the nozzle 12 . 7a is the normal line at the grid projection position on the surface of the roll 7, and
is an angle of 30 to 40" with respect to the normal 7a (projection angle A)
is tilted to spray the grid with roll 7 and 5
They are arranged at a distance of 0 to 10Qmnl.

A case in which this device is used to project a grid made of alundum abrasive grains to form dull grains having shape directionality on the outer peripheral surface of the dull roll will be described.

- As an example, a work roll for cold rolling is placed on the spinner roll 6.6, and the spinner roll 6.6 is rotated to rotate the roll 7, and the allundum abrasive grains are mixed in from the nozzle 12. By spraying the powder onto the roll surface and roughly moving the cart 5 perpendicular to the figure, a directional dull pattern is formed on the entire outer circumferential surface of the roll, thereby producing a dull roll. The sprayed grid is struck onto the outer peripheral surface of the roll, and a long recessed portion is formed in the outer peripheral surface in the circumferential direction of the roll. In addition, in this explanation, alundum abrasive grains were used as the grid and were projected onto the surface of the roll base material by the blasting method to form dull grains, but the ￥A manufacturing method is not limited to this. Rather, it may be any material that can obtain the desired roughness and density depending on the material of the roll, usage conditions, etc., and may be appropriately changed to other known materials or materials with ridal stitches formed by known means. Furthermore, although the roughness and density of the burrs can be changed, it is desirable that the roughness be 2.7±0.3 Ra1 density 20000/c# in a rolled material made of ordinary steel.

Example Embodiments of the invention will be described based on the drawings.

FIG. 1 is a front view of a dull roll 1 manufactured using the above-mentioned apparatus. On the outer circumferential surface 2 of the roll, a circumferentially elongated dowel 3 is formed, and the dowel density is 21500/cd, which is about the same as that of a conventional dull roll. FIG. 2 is a partially enlarged sectional view of the roll outer circumferential surface 2 taken along line A-A. The dowel 3 has a predetermined roughness R, which in this example is R-2.7±0.3JJ.
It is mRa.

Next, the life characteristics of the dull roll A according to the embodiment of the present invention, the conventional dull roll B (that is, a dull roll with no shape directionality), and the scratch roll were compared, and the results are shown in FIG. . In conventional scratch rolls, the initial roughness of the roll surface is quickly lost due to wear, requiring re-grinding, or even re-grinding becomes difficult, leading to the end of its life. On the other hand, the dull roll A has a life characteristic comparable to that of the conventional dull roll B, and has an extremely better life characteristic than the scratch roll.

Furthermore, FIG. 4 is a graph showing the influence of dull roll A and dull roll B on the elongation characteristics of the rolled material. The rolling reduction ratio of the rolled material when applying the same rolling load is dull roll B
On the other hand, the dull roll A is larger.The dull roll of the example of this invention improves the elongation property of the rolled material compared to the conventional dull roll, and in the comparative example, the elongation property of the rolled material is Improved by 15%.

As described in detail, according to the present invention, the dulls having shape directionality are formed in the circumferential direction of the dull roll, so that it is possible to sufficiently prevent seizing of the rolled material and to prevent the rolling material from being exposed. It has the effect of improving the elongation characteristics of the rolled material and roughly improving the life characteristics of the roll itself.

Note that the use of the dull roll according to the present invention is not limited to the work roll of the final stand of a rolling mill, but in order to obtain the desired effect, it is desirable to use it at least as the work roll of the final stand.

[Brief explanation of drawings]

Fig. 1 is a front view of a $511 embodiment of the present invention, Fig. 2 is a partially enlarged cross-sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 shows a dull roll according to an embodiment of the present invention and a conventional one. Fig. 4 is a graph comparing the life characteristics of the dull roll of the embodiment of this invention and a conventional dull roll, and Fig. 5 is a graph comparing the influence of the dull roll of the embodiment of this invention on the elongation characteristics of the rolled material. It is a partial sectional view of an example of the apparatus used for manufacturing the dull roll of the invention. 1... Dull roll, 2... Dull roll outer peripheral surface, 3
...Dull eyes.

Claims (1)

[Claims] What is claimed is: 1. A dull roll having dull stitches formed on an outer circumferential surface, wherein the dull stitches have shape directionality in the circumferential direction of the roll.