JPH08276204A - Cold rolling method for stainless steel strip - Google Patents

Abstract

PURPOSE: To provide a technology by which the cold rolling of a stainless steel strip is performed by using work rolls with one kind of crown applied even when the kind and the size of a rolling stock to be rolled are changed. CONSTITUTION: This is a cold rolling method for a stainless steel strip when performing the cold rolling of the stainless steel strip S by a cluster rolling mill by making the total quantity of the crowns of work roll 1 and intermediate roll 2 1/10000 to 4/10000 and within the range of 5/10000 to 8/10000 for the operation quantity of the crown of a backup roll 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold rolling method for stainless steel strips, and more particularly, to rolling without changing work rolls used in a cluster rolling mill even if the width or the type of steel strip is changed. Related to the technology.

[0002]

2. Description of the Related Art A cold rolling mill used for producing a stainless steel sheet generally has a small diameter (50 to 50 mm) in order to obtain a high pressure reduction ratio during rolling and to give a gloss to the surface of the rolled stainless steel sheet.
A work roll having a diameter of about 100 mm) is used. In such a work roll having a small diameter, since the deflection of the roll shaft center is complicated and large, as shown in FIGS. 1A to 1C, the intermediate roll 2 is provided around the work roll 1. Further, the backup rolls 3 are arranged in a cluster so as to be overlapped with each other to reduce the deflection. That is, the small-diameter work roll 1 is supported by the intermediate roll 2 and the backup roll 3 having a cluster structure, and the backup roll 3 is divided into a plurality of edge portions, quarter portions, center portions, etc. in the axial direction (see FIG. In (), a so-called cluster rolling mill that is divided into 7 is used. The divided backup roll 3 is also equipped with a device for adjusting the crown pattern of the backup roll 3 by an eccentric bush mechanism, and has a great ability to control the sectional shape of the steel plate S. For example, steel plate S
When the cross-sectional shape of No. 2 becomes convex by rolling, the extrusion amount (y _E or y _O ) at the edge portion or quarter portion of the divided backup roll 3 is changed to the shape shown in FIG.
As shown in FIG. 4, the steel sheet is arranged in a concave shape so that the cross-sectional shape of the steel sheet after the rolling is flat.

However, in actuality, the shape controllability of the steel plate cross section is insufficient only by controlling the crown of the backup roll 3, so in order to obtain an appropriate rolling cross section, the intermediate roll 2 is provided with the roll bender 5, or the upper and lower rolls. The work rolls 1 are arranged so as to be displaced in the steel plate width direction (so-called roll shift) to enhance controllability. However, even then, in many cases, it is not possible to correct the steel plate cross-sectional shape to a sufficient degree.

Therefore, this shortage is compensated by changing the crowns of the work roll 1 and the intermediate roll 2. That is, a plurality of types and a plurality of work rolls 1 and intermediate rolls 2 having different crown amounts are prepared, and before rolling, they are exchanged with appropriate rolls in advance according to the strip width and steel type of the stainless steel strip that is the material to be rolled. Is the way to do it. here,
The crown amount of the work roll 1 and the intermediate roll 2 is an amount obtained by dividing the difference in diameter between the center and the end of each roll by the barrel length of the roll.

However, having a plurality of types of work rolls 1 and intermediate rolls 2 increases the number of these rolls held, increases the load on the roll shop, and limits the rolling schedule and the pass schedule.
It is not preferable in terms of operation and economy.

[0006]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides a method of cold rolling a stainless steel strip by using a work roll provided with one type of crown even if the steel type or size of the material to be rolled is changed. The purpose is to provide the technology to do.

[0007]

In order to achieve the above-mentioned object, the inventor diligently studied rolling with the same crown and devised the present invention. That is, according to the present invention, when the stainless steel strip is cold-rolled by the cluster rolling mill, the total amount of crowns of the work rolls and the intermediate rolls is 1 / 10000-1000.
It is 4/10000, and the cold rolling method of the stainless steel strip characterized by cold-rolling a stainless steel strip within the crown operation amount of a backup roll within the range of 5/1000 to 8/10000. Further, the present invention, when cold rolling a stainless steel strip by a cluster rolling mill,
The work roll crown amount is 3/100000 to 10 /
At 100000, the crown amount of the intermediate roll is 7/100
000 to 3/10000, and the crown operation amount of the backup roll is 5/1000 to 8/10000
It is also a method of cold rolling a stainless steel strip, characterized in that the stainless steel strip is cold-rolled within the range.

[0008]

According to the present invention, the crown amount of the work roll and the intermediate roll is regulated as described above, and the crown pattern operation amount of the backup roll is limited.
Even if the steel type and strip width of the stainless steel strip are changed, it is possible to perform cold rolling while ensuring a good rolling shape by selectively using one type of work roll and intermediate roll.

The lower limit of the crown amount of the work roll or the intermediate roll is set as described above because if it is smaller than this, the ear extension occurs as the plate width of the stainless steel strip becomes smaller, while the upper limit is set to the above. The reason for determining the value is that the larger the width of the plate, the more the medium elongation occurs. Hereinafter, the content of the present invention will be described with reference to FIGS.

First, in order to obtain the best steel plate shape, the elongation strain distribution ε _x of the steel plate on the work roll exit side is uniform within the plate width, that is, the edge portion ε _x (E) and the quarter portion ε _x.
(Q) and the center portion ε _x (C) have no difference. In addition, it is easy to understand intuitively as a measure of the shape amount, and it is often used in the field that the difference in end extension strain Λ
₂ and quarter elongation strain difference Λ _4, which are defined by the equations (1) and (2) (Mitsubishi Heavy Industries Technical Report, vol. 25, No. 4).
(1988), page 333).

Λ ₂ = ε _x (E) −ε _x (C) (1) Λ ₄ = ε _x (Q) −ε _x (C) (2) Further, the shape evaluation function J is expressed by the equation (3). Is defined. J = Λ ₂ ² + Λ ₄ ² Therefore, in order to obtain the best plate shape, the shape evaluation function J
Should be minimized (when Λ ₂ is the horizontal axis and Λ ₄ is the vertical axis, the closer J is to 0, the smaller). Specifically, it is adjustment of the crown amount of the work roll and the intermediate roll or the crown pattern of the backup roll. In addition to the above J, a shape evaluation function (for example, a quadratic orthogonal function or a steepness difference defined by the following equation (4))
However, in the present specification, the J
And the steepness difference Λ (distance from the origin in the above figure).

Λ = (Λ ₂ ² + Λ ₄ ² ) ^1/2 Next, the inventor used a cluster rolling mill having the specifications shown in Table 1,
A SUS304 material having a plate width of 1000 mm was cold-rolled with various work rolls and intermediate rolls.

[0013]

[Table 1]

As shown in FIG. 2, the results were arranged as a relationship between the total crown amount of the work roll and the intermediate roll and the edge center steepness difference Λ of the steel sheet. From FIG. 2, the total amount of crowns of the work roll and the intermediate roll is 1/100.
When 00 to 4/10 000, the crown operation amount of the backup roll (shown by the line type in the upper part of FIG. 2) is 5/1000.
By setting it within the range of 0 to 8/10000, the edge / center steepness difference becomes negative, that is, the belly stretch is shown, and the ear stretch becomes large as the crown increases. Therefore, when the total amount of crowns of the work roll and the intermediate roll is 1/10000 to 4/10000, the crown operation allowance of the backup roll is 5/1000 to 8 /
By setting it within the range of 10,000, the difference in elongation between the edge and the center can be eliminated.

Further, FIG. 3 shows the difference between the work roll crown amount and the edge / center steepness difference together with the crown amount of the intermediate roll, which shows that the crown amount of the work roll can be sufficiently compensated by the crown amount of the intermediate roll. The crown amount of the intermediate roll is shown line by line in the upper part of FIG. Further, FIG. 4 shows a comparison between the crown amount of the backup roll bearing and the edge / center steepness difference under the same strain. From this, it can be said that the high deformation resistance material has a large edge elongation, but if the total amount of crowns of the work roll and the intermediate roll (shown by the line type in the upper part of FIG. 4) is set to 1/10000 to 4/10000, backup By operating the roll, the steepness of the edge center can be made zero.

[0016]

Example: The steel type is SUS304, the same, and the plate width is 1050.
Table 1 shows two types of stainless steel plates, mm and 1250 mm.
It cold-rolled with the cresta rolling machine shown in. At that time, as a work roll, the crown amount is 0, 100, 300 μ.
Three types of m / 800 mm (barrel length) and only one type of intermediate roll having a crown amount of 300 μm were used. During rolling, the crown pattern of the backup roll was changed so that the steel sheet had the minimum coexisting shape.

As described above, the results are summarized by plotting the edge extension strain difference Λ ₂ of the steel sheet on the horizontal axis and the quarter extension strain difference Λ ₄ on the horizontal axis (FIGS. 5A and 5B). )). Figure 5
5A shows the result of rolling a steel plate having a plate thickness of 1050 mm, and FIG. 5B shows the result of rolling a steel plate having a plate thickness of 1250 mm. The mark shows the data of 100 μm. From the result of FIG. 5, in the current rolling schedule, the crown amount is 10
If a work roll of 0 μm is set, the plate width will be 1050
mm and 1250 mm, the minimum coexisting shape is 0
It was revealed to be close to. Therefore, as a result of performing the same test operation for all rolling target materials of the cresta rolling mill, a certain amount of crown is given to the intermediate roll and the work roll, and the integrated amount is used to cope with the change of the strip width. It was found that the crown pattern of the backup roll can cope with the change in deformation resistance due to.

[0018]

As described above, according to the present invention, in the cold rolling of the stainless steel plate by the cresta rolling machine,
Even if the steel type and strip width of the material to be rolled are changed, it is possible to obtain a good shape without replacing the work roll and the intermediate roll. As a result, we were able to achieve a reduction in the number of rolls held and labor saving in replacement work.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cresta rolling machine, in which (a) is a side cross section, (b) is a front view, and (c) is a view showing a crown pattern of a backup roll.

FIG. 2 is a diagram showing a relationship between a total amount of crowns of a work roll and an intermediate roll and an edge center steepness difference of a steel plate.

FIG. 3 is a diagram showing the relationship between the crown of a work roll (WR) and the edge center steepness difference of a steel plate.

FIG. 4 is a diagram showing a relationship between a crown operation amount of a backup roll (BUR) and an edge center steepness difference of a steel plate.

5A and 5B are diagrams showing the results of carrying out the present invention, in which FIG. 5A is an example of a plate width of 1050 mm, and FIG.

[Explanation of symbols]

1 Work Roll (WR) 2 Intermediate Roll (IMR) 3 Backup Roll (BUR) 5 Bender S Steel Plate y _E Edge Extrusion Amount y _O Quarter Extrusion Amount

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location 8315-4E B21B 37/00 116P

Claims (2)

[Claims] 1. When cold rolling a stainless steel strip by a cluster rolling mill, the total amount of crowns of work rolls and intermediate rolls is 1/10.
A cold rolling method for a stainless steel strip, characterized in that the stainless steel strip is cold-rolled within a range of 5 / 10,000 to 8/10000 with the crown operation amount of the backup roll being 000 to 4/10000. 2. When cold rolling a stainless steel strip by a cluster rolling mill, the crown amount of work rolls is 3/100000 to 10 /
At 100000, the crown amount of the intermediate roll is 7/100
000 to 3/10000, and the crown operation amount of the backup roll is 5/1000 to 8/10000
A method for cold rolling a stainless steel strip, which comprises cold rolling the stainless steel strip within the range.