JPS61266102A - Work roll shift rolling method - Google Patents

Abstract

PURPOSE:To improve remarkably the degree of freedom of the transverse size of a rolling material and to improve productivity by using the material which is subjected to edge grinding and is to be rolled and subjecting such material to cold rolling while shifting work rolls in the transverse direction of the material to be rolled thereby preventing the formation of the flaws of edge marks. CONSTITUTION:The angle parts 1a of the material 1 to be rolled are chamfered by edge grinding and thereafter the material is fed to a rolling state. The edge grinding is executed by cutting tools or grinding wheels at the four angle parts and may be executed at only the two points where there are the burrs formed by a trimmer. The material to be rolled is thereafter subjected to the cold rolling while the work rolls are shifted in the transverse direction thereof. Since the material to be rolled is chamfered by the edge grinding, the flaws of the edge marks are not formed on the work rolls even if the material to be rolled is hard. The free selection of the transverse size of the material to be rolled thereafter is thus made possible and the productivity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technique of applying a work roll shift rolling method in cold rolling.

[Prior art and its problems]

The work roll shift rolling method frees up the rolling schedule by shifting the work rolls that are in direct contact with the material to be rolled in the width direction of the material to be rolled, adjusts the crown shape of the work rolls, and improves the quality of the rolled product. This is a technology that improves the shape and dimensional accuracy of.

By the way, when rolling a material to be rolled, the parts of the work rolls that correspond to the corners of the material to be rolled are subjected to the most severe usage conditions, so flaws called edge marks are likely to occur in those parts. In this case, since the material to be rolled is soft, edge marks are not generated even at the corners of the work roll of the material to be rolled. Therefore, the edge marks are not transferred to the material to be rolled.

Moreover, when applying the above-mentioned work roll shift rolling method to improve the shape and dimensional accuracy of the rolled product, the corners of the work roll, which are subjected to the most severe usage conditions, of the rolled material fluctuate ( This has the effect of further suppressing the occurrence of edge marks on work rolls.

However, when the material to be rolled is cold rolled, since the material to be rolled is hard, edge marks are generated at the corners of the material to be rolled by the work rolls. In particular, when the material to be rolled has been dreamed in the previous process, this is a particular problem because the curvature of the dream promotes the formation of edge marks on the work roll.

If the work roll on which such edge marks have occurred is used as is and the material to be rolled is rolled under conditions such that the material to be rolled later comes into contact with the portion where the edge marks have occurred, the edge marks will be removed. The flaws are transferred to the rolled material and the rolled material is also scratched.

Moreover, when applying the above-mentioned work roll shift rolling method while using a work roll with edge marks,
The edge mark will be transferred over a wide range to the rolled material.

The flaws transferred to the rolled material clearly remain even after the rolled material passes through the final stand mill, so the commercial value of the finished product is significantly reduced and the product is usually unusable.

Specifically, the material to be rolled, which is made of low carbon steel with a carbon content of 0.08% and which has been dream-rolled in the previous process, is rolled into one coil (total length: 1200 m) at a rolling reduction rate of 45% on the #1 stand.
), the forged steel work roll (hardness: Hs 93) has a hardness of < 0.01 as shown in Figure 3 (graph showing the results of measuring the surface shape of the work roll).
It was confirmed that edge marks with a depth of mm were generated.

Therefore, we would like to prevent the occurrence of edge marks on the work roll, but until now there has been no suitable preventive means, so the rolled material that will be rolled later does not come into contact with the part of the work roll where the edge mark has occurred. In this way, the material to be rolled is passed through the plate.

For example, a narrow width material is selected as the material to be rolled later, so that the portion of the work roll where the edge mark has occurred does not come into contact with the material to be rolled. However, when creating such a rolling schedule, a major problem is that the degree of freedom in the rolling schedule becomes extremely small.

In addition, if it is not possible to select a narrow material to be rolled later, it is unavoidable to reassemble all work rolls to ones that do not have edge marks. Ta.

The present invention was created in view of such circumstances,
The purpose is to provide a technology that enables operations with a high degree of freedom in rolling schedules even in cold rolling.

[Means for solving problems]

The work roll shift rolling method of the present invention, which was devised to achieve the above object, uses a rolled material that has been subjected to edge scraping by means such as cutting or grinding, and shifts the work roll in the width direction of the rolled material. It is characterized by cold rolling.

[Effect]

When cold-rolling a material to be rolled using the method of the present invention, the corners of the material to be rolled are chamfered by ear shavings before rolling, so there are no edge marks on the work rolls that correspond to the corners of the material to be rolled. Never occurs. As a result, the width dimension of the rolled material to be rolled later can be freely set, and the degree of freedom in the rolling schedule is greatly increased.

〔Example〕

Hereinafter, the method of the present invention will be specifically explained with reference to the accompanying drawings.

FIG. 1 is a schematic explanatory diagram showing a state in which an ear pickpocket according to the present invention is being performed. The drawing shows the first stage of the cold rolling process.
FIG. 3 shows a longitudinal cross-sectional view at the entrance of the stand mill.

In the figure, (1) is a material to be rolled that is continuously fed to the cold rolling process, and the material to be rolled (1) is fed in a direction perpendicular to the plane of the paper.

Cutting bits (2)...(2) are placed in contact with the four corners (1a)...(1a) of the material to be rolled (1).
are arranged, and the corners (1a)...(1) of the rolled material (1) are continuously fed by the cutting tools (2)...(2).
a) is continuously cut and removed so that the ear can be removed.

However, the rolled material (1) has its corners (1a)...(1a
) is chamfered with an edge pick and then sent to the rolling process, so even if the cold rolled material (1) is hard, it is possible to suppress the occurrence of edge marks on the work rolls. It is possible to prevent the edge mark from being transferred to finished products. As a result, the width dimension of the rolled material to be rolled later can be freely selected, and the degree of freedom in the rolling schedule is greatly increased.

Moreover, since the work roll shift rolling method is used to improve the shape and dimensional accuracy of the rolled product, the rolled material of the work roll is subjected to the most severe usage conditions, just as in the case of hot rolling. The part that corresponds to the corner fluctuates (dispersion)
This further suppresses the occurrence of edge marks on the work roll.

In addition, in the above explanation, cutting hide (2)...(2)
It was decided to carry out edge scraping of the rolled material (1) by
A grindstone (of course, the grindstone is rotated) is placed in place of the cutting tool (2)...(2), and the corner portions (1a)...(]a) of the material to be rolled (1) are cut by the grindstone. It is also possible to remove the abrasive material and perform an ear pickpocket.

As shown in Fig.
) at the four corners (1a)...(1a), but for example, only two locations where the burrs of the trimmer are protruding (for example, the lower surface of the rain) may be used.

Further, it goes without saying that the step of performing edge scraping may be performed immediately after the pickling step, which is performed mainly for the purpose of removing scale generated during hot rolling.

Next, specific examples of the method of the present invention will be described. Using the method of the present invention, the rolled material made of low carbon steel with a carbon content of 0.08% and dreamed in the previous process is rolled into one coil (total length: 1200 mm) at a rolling reduction rate of 45% on #1 stand.
m) Forged steel work roll (hardness: Hs 93) when subjected to cold rolling (cold rolling with 3 tandem mills)
As shown in Figure 2 (graph showing the results of measuring the surface shape of the work roll), there were no flaws that appeared to be edge marks, and there were no defects on the next product rolled by shifting the work roll. No scratches such as those transferred by Edgemark were observed.

〔Effect of the invention〕

As detailed above, by using the method of the present invention, it is possible to suppress the occurrence of flaws called edge marks on work rolls even during cold rolling, and as a result, the width dimension of the rolled material to be rolled later can be freely adjusted. This will greatly increase the flexibility in rolling schedules. Therefore, it can be said that the present invention can provide an effective means for improving productivity in the cold rolling process.

[Brief Description of the Drawings] Figure 1 is an explanatory diagram showing the state in which edge scraping according to the present invention is being performed, and Figure 2 is the surface shape of a work roll when cold rolling is performed using the method of the present invention. FIG. 3 is a graph showing the results of measuring the surface shape of a work roll when cold rolling is performed using a conventional method. 1: Rolled material, 1a: Corner, 2: Cutting tool.

Claims (1)

[Claims] (1) A work roll shift rolling method characterized in that cold rolling is performed using a material to be rolled which has been subjected to edge scraping while shifting the work roll in the width direction of the material to be rolled.