JPS6027405A - Rolling method - Google Patents

Abstract

PURPOSE:To improve further the rolling characteristics in a cluster mill by combining the backup rolls of a variable crown type and a movable sleeve type to supplement their characteristics and weaknesses with each other and making the diameters of work rolls small and their peripheral speeds different. CONSTITUTION:A VC roll obtained by forming a backup roll of cluster mill into a variable crown one shows its comparatively excellent characteristics, but has weaknesses in sheet profile control and heavy rolling-reduction performance. When a pair of movable sleeve type HC rolls are added to said rolls, the heavy rolling-reduction performance, shape control, and sheet profile control are made better, and the comprehensive characteristics are improved. The rolling characteristics are further improved by using an NMR mill system formed by combining said system with the heavy rolling-reduction of Sendzimir multiple small rolls or a PV mill system formed by adding the different peripheral speed rolling of different diametral upper and lower work rolls to said system.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rolling method that significantly enhances the crown shape control effect and at the same time enables heavy reduction rolling.

Comparing the advantages and disadvantages of recent rolling methods, each has considerable advantages, but they also have their own drawbacks. Therefore, it is desired to develop a rolling method that is superior in terms of performance, equipment, operation, etc.

Among various rolling methods, variable crown roll (hereinafter referred to as
It's called VC role. ) has been shown to be relatively effective in meeting various requirements. However, even this method had some drawbacks in terms of control performance and performance under strong pressure.

Next, Table 1 shows a comparison of the advantages and disadvantages of typical conventional rolling methods.

Table 1 In Table 1, HO mill refers to the workpiece and
This is a new 6-layer rolling mill that has an intermediate roll between the roll and backup roll, and by shifting the intermediate roll in the axial direction, changes the work roll deflection to control the crown and shape of the steel strip.

The P-mill controls the crown and shape of the copper strip by reducing the rolling load component caused by friction during rolling by varying the circumferential speeds of the upper and lower work rolls.

The NMR mill is a combination of a conventional four-layer rolling mill and a Sendzimir multi-stage mill, and enables strong reduction.

An object of the present invention is to obtain a rolling method that exhibits excellent effects on at least all of the items listed in Table 1.

The basic idea of the present invention is to use a combination of a VC roll and a sleeve-moving roll as a back-up roll in a cluster mill in order to achieve high pressure, shape and plate profile control.

Further, by developing this idea, it is possible to improve control performance by incorporating smaller diameter work rolls and rolling at different circumferential speeds. Further, regarding the VC roll, the pressure chamber can be divided into a plurality of parts in the longitudinal direction, and these VC rolls can be appropriately combined to perform appropriate shape control.

In rolling mills in which multiple rolls circumscribe the outer circumference of one roll at the same time (for example, cluster mills, Sendzimir mills, etc.), a VC roll and a sleeve-moving roll are used as the circumscribing rolls, and small-diameter work rolls can be rolled at different circumferential speeds. By combining these effects, the crown shape control effect can be significantly enhanced. The combined effect of both rolls is greater when small diameter work rolls are used. Even for strong rolling, it is more effective to use a combination of small-diameter work rolls and rolling at different circumferential speeds. A single-mill mill may also be used as a scale-breaking mill, and scale-breaking can be done more effectively than conventional mills.

As the diameter of the work roll becomes smaller, the deflection of the roll becomes Va
It becomes easier to follow the bulge shape of the C roll. Therefore, by introducing a different type of VC roll (one with a different number of pressure chamber compartments in the longitudinal direction) and giving it a complex roll deflection that was previously impossible, we have significantly improved the shape, plate profile, and strong pressure control function. can be improved.

Next, examples of the rolling method of the present invention will be described.

<Example 1> (1) Rolling line: hot rolling line (2) Rolling base material dimensions: thickness 35 g x width 1200 words x weight 25 tons (3) Mill used: cluster mill (on the first stand of the finishing mill Application. Fig. 1 (Shu) (4) Work roll: Small diameter different circumferential speed roll (5) Backup roll: Combination of vC roll and sleeve movable roll. Fig. 1 (A), (B), (C 1 is v in
CC roll 2 is a sleeve moving roll, and 3 is a different type of VC C roll.

(Reduction rate of 6th stand 1st stand near 0% (7) Effects: Compared to rolling with a normal 4-layer mill, the rolling load was less than %, and in addition to improving the strong rolling performance, the crown shape control ability was doubled.

<Example 2> (1) Pressure! Line: Cold rolling line (2) Rolling base material dimensions: Thickness 3. B M X width 1250
mx weight 45 tons (3) Mill used: Cluster mill (applied to the first stand of tandem mill) (4) Work roll: Small diameter roll (Figure 1 (Toughness) Different circumferential speed rolling (5) Backup roll : Different types of VC rolls 1 and 3 shown in Fig. 2 were used.VC roll 1 has no partition in pressure chamber 11, and VC roll 3 has pressure chamber 12 divided into two in the longitudinal direction. This VC roll is used in a roll arrangement as shown in FIG. 1 CB).

(6) 1st stand rolling reduction near 5cm (7) Effects: ■ When only C roll 1 is used, the shape of the rolled material only changes from ear wave to medium elongation, and medium elongation near the welding part. It cannot be treated when stretch and ear waves occur together. However, when different types of VaC rolls 3 are used, the crown shapes of both rolls become as shown in FIG.
When O-ru 3 was used, the middle elongation and ear waves were also eliminated.

When the VC roll 3 was further worked under good rolling conditions, quarter elongation (elongation that occurs approximately % from both edges of the rolled material in the width direction) occurred. This proves that it is possible to conversely control quota growth.

<Example 3> (Rolling line: cold rolling line, the first stand was the mill of Example 1 (Fig. 1 (B)), and the second stand was the mill of Example 2 (Fig. 1 (B)). C)).

(2) Rolling base material dimensions: thickness 4.5 III x width 100
100O Weight: 4 g ton (3) Mill used: Cluster mill (4) Reduction rate: 282% (5) Effect: Conventionally, material thickness: 4. Although it was possible to roll a material with a thickness of 0.5 mm to a thickness of about 0.5 mm, in this example, it became possible to roll a material with a thickness of 2.8 mm to a thickness of about 0.5 mm.

Due to the small diameter work rolls on the entry side of the first and second stands, the plate profile has been improved by 15μ and the edge drop has been improved by 15μ with a nominal width of 1000 words, and quarter elongation, which could not be dealt with in the past, has been drastically reduced. A significant improvement in flatness was achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a cluster mill to which the rolling method of the present invention is applied. FIG. 2 is a schematic explanatory diagram of a VC roll applied to the method of the present invention. FIG. 3 is a graph showing the VaC roll crown shape shown in FIG. 2.

Claims (3)

[Claims] (1) A rolling method in which a backup roll is used in combination with a variable crown roll and a movable sleeve roll in a cluster mill, and the individual rolls are arranged diagonally up and down. (2) The method according to claim 1, characterized in that, in the mill, the work rolls are made smaller in diameter and configured to have different circumferential speeds, and that different circumferential speed rolling is incorporated. 3. The method of claim 1, wherein the variable crown roll is configured with different variable crown shapes and incorporates shape profile control.