JPH0313211A - Multistage rolling mill having integral type backup roll - Google Patents

Abstract

PURPOSE:To control flatness over a wide range by imparting roll crown converged toward one end to one set of rolls and the roll crown curved to the waveform of one wavelength to the other one set, respectively, and reversing the axial directions of the respective crowned roll pairs to allow the axial movement of the rolls. CONSTITUTION:The roll crown converged toward one end is imparted to at least two pieces one set of the rolls (work) 2, 2 among the work rolls 2, 2, intermediate rolls 3, 3, and integral type back up rolls 4, 4 of the multistage roiling mill. The roll crown curved to the waveform of one wavelength is imparted in the other two pieces one set of the rolls (intermediate) 3, 3. The axial directions of the respective crowned roll pairs are reversed to allow the axial movement of the rolls. The generation of nonuniform roll face pressures in the axial direction of the rolls is obviated in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multi-high rolling mill with a capacity equivalent to 12 stages, which has an excellent flatness control function and is capable of applying a high rolling load.

(Prior Art) Cold rolling of difficult-to-work materials such as stainless steel and silicon steel is often performed in multi-high rolling mills such as 12-high and 20-high rolling mills. In such a multi-high rolling mill, since the diameter of the work rolls can be reduced, there is an advantage that a high rolling reduction can be achieved with a small rolling load compared to a conventional vertically arranged rolling mill. However, on the other hand, when the diameter of the work roll is made small, the deflection of the roll becomes large, so there is a drawback that the rolled material is likely to have a defective shape.

Therefore, various solutions have been proposed in the past in order to prevent the occurrence of such shape defects.

One such method is to control the shape of the rolled material by dividing the outermost backup roll into a plurality of parts in the axial direction and adjusting the amount of displacement of each divided roll. However, in this method, there are many intermediate rolls between the backup roll and the work roll (the more intermediate rolls there are, the more the effectiveness is diminished, so in a multi-high rolling mill equipped with many intermediate rolls such as 12 stages) , he was unable to fully demonstrate his abilities.

To improve this point, the
A method of using a work roll bender or an intermediate roll bender together with the above-mentioned backup roll displacement adjustment method was proposed in the above publication. However, this method has the disadvantage that the equipment becomes complicated, and as the roll becomes thinner or the roll barrel becomes longer, the pending force does not work all the way to the center, so the control force remains only at the ends of the rolled material. there were.

Further, Japanese Patent Publication No. 63-207405 and the like proposes a method in which one end of the intermediate roll is tapered and each of the intermediate rolls is shifted independently in the axial direction. However, even in this method, the control force is limited to only a portion around the taper.

Further, in Japanese Patent Publication No. 63-30104, etc., a vertically arranged rolling mill is proposed in which the rolls are provided with an S crown that can be approximated by a cubic equation and are shiftable in the axial direction.

The development of such devices has provided considerable control over belly extension and ear extension.

However, it is still not sufficient, and improvements in this layer are desired.

Furthermore, with the above-mentioned device, it is hardly possible to control compound elongation in which quarter elongation, belly elongation, ear elongation, etc. are mixed, and improvements in this have also been desired.

In addition, in conventional multi-high rolling mills, the backup roll has to be split in order to control the shape, and there has been a problem in that a sufficiently high rolling load cannot be applied.

Furthermore, when split backup rolls are used, uneven surface pressure between the rolls is likely to occur in the roll axis direction, and the eccentric mechanism is complex, making mill design difficult and the equipment cost high. was left behind.

(Problems to be Solved by the Invention) This invention advantageously solves the above problems, and not only further improves the shape control effect of belly elongation and ear elongation, but also improves quarter elongation and alternate layer compound elongation. We would like to propose a multi-high rolling mill equivalent to 12 stages, which has excellent shape control ability that can correct complex shape defects and even edge drops, and can apply a high rolling force of 1. purpose.

(Means for Solving the Problems) That is, the present invention provides a multi-high rolling mill in which a plurality of intermediate rolls and an integral backup roll are sequentially arranged behind a pair of work rolls, the work rolls, the intermediate rolls, and the backup rolls. A set of at least two rolls selected from a group of rolls is provided with a crown tapered at one end, while a set of at least two rolls selected from the group of rolls is provided with a crown tapered at one end. Each roll is provided with a roll crown extending over at least one wavelength of the same waveform curve, and each pair of crowned rolls is arranged such that the roll axis direction is opposite to each other, and the roll crown is moved in the roll axis direction. A multi-high rolling mill with integral backup rolls, possibly integrated into the mill housing.

Further, the present invention is a multi-high rolling mill having an integral backup roll incorporating a roll bending device in the above-mentioned rolling mill.

In this invention, the one-wavelength waveform curve to be applied to the roll may be one pitch taken from a sine curve, one pitch taken from a third-order or higher-order function, or a Approximate curves are advantageously fitted, and among them, a curve extracted by one pitch from a sine curve and its approximate curve are particularly advantageously fitted.

The present invention uses a combination of a roll pair having a crown tapered at one end as described above and a crown extending over at least one wavelength of the waveform curve, thereby achieving an improvement in comparison with the prior art, as described later. Since the shape control ability is greatly improved, the conventional shape control by extruding a split backup roll is no longer necessary, making it possible to use an integrated backup roll. The use of an integral backup roll is something that has been achieved for the first time in this invention.

Hereinafter, this invention will be specifically explained based on the drawings.

FIGS. 1(a) and 1(b) show the roll arrangement of a multi-high rolling mill according to the invention in side view and front view.

In the figure, l is a rolled material, 2 is a work roll, 3 is an intermediate roll, and 4 is an integral backup roll.A pair of work rolls 2 are arranged above and below with the rolled material 1 in between. Behind the work rolls 2 are a total of 4 intermediate rolls 3, 2 each, and behind the intermediate rolls 3 are 6 integrated backup rolls 4, 3 each on the upper and lower sides.
These machines constitute a 12-high rolling mill.

Note that 5 is a roll bending device.

Of these, all of the work rolls 2 are provided with a roll crown whose one end is tapered, and the intermediate roll 3 is provided with a roll crown consisting of a waveform curve that can be approximated by a sine curve of 1 1000 minutes, and each roll axis is provided with a roll crown that is tapered at one end. The rollers are arranged vertically in opposite directions, and have a structure that allows them to be shifted in the roll axis direction.

The rolls to which a single taper crown and a waveform curve that can be approximated by one pitch of a sine curve are not limited to the above examples, but can be selected from among the work roll 2, intermediate roll 3, and backup roll 4. They can be freely selected and combined.

In addition to the above-mentioned sine curve and its approximation curve, the waveform curve to be provided may be a waveform curve obtained by extracting one pitch across the coordinate origin from a higher-order equation of 3rd order or higher, or even an approximate curve thereof. It's okay.

Further, the roll shift device may be either hydraulic or electric.

(Function) As shown in Fig. 2 (a) to (d), a single tapered roll with one end tapered and ground is installed in the opposite direction to the roll axis direction.
It shows the roll gap change when shifting in the axial direction.

As is clear from the figure, the thickness of the edge of the rolled material can be adjusted by changing the set value of the length (x) of the edge of the rolled material rolled on the tapered grinding surface, so edge drop reduction control is possible. can be done effectively.

Next, FIGS. 3(a) to (C) show the rolls when a pair of rolls each having a corrugated roll crown that can be approximated by one pitch of a sine curve is installed in opposite directions in the roll axis direction and shifted in the axial direction. Indicates gap change.

FIG. 5A shows a case where the pair of rolls are arranged opposite each other and the roll gap is constant in the axial direction. ) is (
This is a case where each roll is moved in the direction of the arrow from state a), and the roll gap is wide at the center and narrow at the ends. In addition, in FIG. 3(C), each roll is moved in the opposite direction to that in FIG. 3(b), and the roll gap is narrow at the center and wide at the ends.

Therefore, by appropriately shifting a pair of rolls provided with a wavy roll crown that can be approximated by one pitch of a sinusoidal curve in the roll axis direction, it is possible to effectively correct the edge elongation and belly elongation.

Next, FIG. 4 shows a comparison of the maximum additional rolling loads when using the conventional split type backup roll and the integrated type backup roll according to the present invention.

As is clear from the figure, when the integrated backup roll according to the present invention is used, the reduction is approximately 40% compared to the conventional one.
An increase in rolling load can be expected.

Next, FIG. 5 shows a pair of rolls provided with a single tapered crown (hereinafter simply referred to as T-crown) as a work roll (WR) of the 12-high rolling mill shown in FIG. 1 above, and as an intermediate roll (IMR). Using a pair of rolls with a wave-shaped roll crown (hereinafter simply referred to as S-crown) that can be approximated by one pitch of a sine curve, we investigated the shape control ability when each roll was individually shifted appropriately in the roll axis direction. , compared with the case of extruding a split backup roll.

The shape control ability was evaluated by the difference in elongation Δ2 between the center and the ends of the rolled material and the difference in elongation Δ4 between the center and a part of the quarter.

As is clear from the figure, in the case of T-crown roll shift and S-crown roll shift alone, a certain degree of control can be expected for ear elongation and belly elongation, but there is almost no hope for quarter elongation or alternating layer composite elongation control. .

Note that split backup roll extrusion can only be expected to provide slight control over quarter elongation and alternate layer compound elongation.

Note that split backup roll extrusion can only be expected to provide slight control over quarter elongation and alternate layer compound elongation.

Figure 6 also shows the results of an investigation into the shape correction ability when a T-crown roll was used as a work roll and an S-crown roll was used as an intermediate roll in the above 12-high rolling mill. The results will be compared with the results obtained when extrusion using split backup rolls was used.

As is clear from the figure, by combining T-crown rolls and S-crown rolls and shifting them appropriately in the roll axis direction, not only can the control effect on ear elongation and belly elongation be greatly improved, but also quarter elongation and compound elongation can be achieved. The ability to correct elongation can also be expected, making it possible to realize flatness control over a wide range.

In this invention, the pair of rolls to which the T crown or W crown is to be applied may be any roll pair, as long as it is a pair of at least two rolls selected from a roll group consisting of a work roll, an intermediate roll, and a backup roll. However, it is more preferable that each roll pair is selected from a group of rolls of the same type, that is, a work roll pair, an intermediate roll group, and a backup roll group. Further, the control effect is greater as the T-crown and W-crown imparting rolls are closer to the material to be rolled, and the arrangement of each pair of rolls is greater in the order of point symmetry, vertical symmetry, and left-right symmetry with respect to the material to be rolled.

Furthermore, if a roll bending device is used in combination, the above effects will be further enhanced.

In addition, when comparing a sine curve and a high-order function curve as a reference line for the waveform curve to be given to the roll, when following a sine curve, the amount of roll crown and the pitch of the waveform can be easily adjusted by simply giving the amplitude and period. It is extremely advantageous in that it can be set easily, and it also has the advantage of good symmetry in the width direction.

On the other hand, in the case of a high-order function curve, as described below, it may not be possible to set the amount of roll crown and waveform pitch arbitrarily, and if you try to set it arbitrarily, it will be significantly more difficult than when following a sine curve. There are some disadvantages in the complexity and also in that the symmetry across the width is not very good.

That is, for example, as shown in Fig. 7, when the center of the roll barrel is set as the origin of coordinates and a waveform curve is given with point symmetry across this origin, the higher-order function is as shown in equation (1) below. Become.

f(x)=a, x10a, xco+a5x' + −+ a
, x''''' (1) In order to arbitrarily set the roll crown amount and pitch, it is necessary to determine the coefficients a, ~a,, so as to satisfy the six equations shown in Table 1.

and (if n=3, that is, 3 as in the following equation (1)')
When expressed by the following odd function, there are two unknowns, al+a, so only two conditional expressions can be considered in equation 2) shown in Table 1.

f (x)lIa+x+a3x3・= (1) 'For example, in order to define the crown amount, (2)- shown in Table 1
1 and (2)-2, it is not possible to select a conditional expression for defining the pitch, and therefore it is not possible to arbitrarily change the crown pitch.

In this way, when a specific roll crown is represented by a high-order function curve, compared to the case where it is represented by a sinusoidal curve, it is difficult to select the crown arbitrarily when the order is low, whereas it becomes extremely complicated when the order is high. A disadvantage remains.

(Example) In the 12-high rolling mill shown in Fig. 1 above, the work roll 2 includes a roll having a single tapered shape (T crown) as shown in Fig. 8(a), and an intermediate roll. Rolls having crowns (S1 crowns) that can be approximated by a cubic equation as shown in FIG.

Then, while shifting the work roll, intermediate roll, and back unroll in the axial direction, the board width is 1000 mm.
A stainless steel plate was rolled from a thickness of 1.2 mm to a thickness of 1.0 mm.

Shape plan views showing the roll arrangement and shape correction ability at this time are shown in FIGS. 10(a) and 10(b), respectively.

In addition, FIG. 10 shows the case where the conventional device is used.
Regarding the shape control ability when similar rolling is performed using T-crown rolls as shown in Figure (b) as intermediate rolls, shifting these rolls in the axial direction and also using extrusion with split backup rolls. The results of the investigation are also shown.

As is clear from FIG. 10 Φ), the conventional device can only obtain shape control capability within a narrow range, and its shape ability to follow compound elongation and quarter elongation is extremely small.

On the other hand, when the device of the present invention is used, a wide control range can be obtained that can sufficiently handle compound elongation and quarter elongation.1. It becomes possible to obtain a plate with a good shape.

In the same <12-high rolling mill, as shown in Fig. 11(a), a round (T-crown) as shown in Fig. 8(b) is placed on two pairs of intermediate rolls, and a workpiece is About the shape control ability when the roll and the two outer pairs of backup rolls are given a crown (S2 crown) that can be approximated by a sine curve ■Pitch component as shown in Fig. 12 and rolling is performed in the same manner as in Example 1. The results of the investigation are shown in Figure 11(b).

Act. 1.3 In the same <12-high rolling mill, as shown in Fig. 13 (a), the rolled material was placed on one of two pairs of intermediate rolls whose pinch points were symmetrical, as shown in Fig. 8 (1)). A round (T-crown) like this, and a crown (32 crowns) that can be approximated by one pitch of a sine curve as shown in Fig. 12 are given to the other intermediate opening and the work roll pair. FIG. 13(b) shows the results of an investigation regarding the shape control ability when rolling was performed in the same manner as in Example 1.

In the same <12-high rolling mill, as shown in Fig. 14 (a), the work roll was given a round (T-crown) as shown in Fig. 8 (a), and the rolled material was sandwiched. A crown (Sl crown) that can be approximated by a cubic equation as shown in Fig. 9 is placed on one of a pair of backup rolls that are symmetrical at the point of view.
FIG. 14(b) shows the results of an investigation regarding the shape control ability when rolling was carried out in the same manner as in Example 1.

As is clear from the figure, even if the rolls provided with C crowns, S crowns, and T crowns were IMi, shape control ability could be ensured, and moreover, it was possible to perform a higher reduction than the conventional reduction blade.

(Effect of the invention) Thus, according to the multi-high rolling mill according to the present invention, edge elongation,
Needless to say, it has excellent correction ability for not only belly stretch, but also quarter stretch, compound stretch, and even edge drop, and therefore flatness control over a wide range can be achieved.

Furthermore, since the multi-high rolling mill according to the present invention can use two integrated backup rolls, it is not only possible to apply a larger rolling load than before (but also to avoid the occurrence of uneven surface pressure between the rolls in the roll axis direction). (This also eliminates the need for complicated mill design, which also contributes to cost reduction.

[Brief explanation of drawings]

Figures 1 (a) and (b) are side and front views showing the roll arrangement of a 12-high rolling mill to which the present invention is applied, respectively, and Figures 2 (a) to (d) are T-crown rolls, respectively. Figure 3 (a) to (C
) are diagrams showing roll gap changes when S-crown rolls are installed parallel to each other in opposite directions and shifted in the roll axis direction, and Figure 4 is a diagram showing a conventional split backup roll or an integrated backup roll according to the present invention. Comparison diagram of maximum rolling load when using rolls, 5th
The figure shows the shape control ability when a T-crown roll pair or an S-crown roll pair is applied individually to the work roll or intermediate roll of a 12-high rolling mill. Figure 7 is a shape control range diagram showing the shape correction ability when S-crown rolls and T-crown rolls are simultaneously used as work rolls and intermediate rolls respectively. (a), et al. are diagrams showing the tapered shape of a single tapered roll, Figure 9 is a diagram showing a suitable S crown that can be approximated by a cubic equation, and Figure 10.11 (a), ( b) is a roll arrangement diagram and a shape control range diagram showing the arrangement of T-crown rolls and S-crown rolls in a 12-high rolling mill, respectively, and Fig. 12 is a diagram showing a suitable S-crown that can be approximated by one pitch of a sine curve. , Both (a) of FIGS. 13 and 14 are roll arrangement diagrams showing the arrangement of the T crown roll and S crown roll in a 12-high rolling mill, and (b) of the same figure is
It is a shape control range figure in each roll arrangement of the same figure (a). ■...Rolled material 2...Work roll 3.
...Intermediate roll 4...Backup roll 5
...Roll benzo ink device Fig. 1 (a) (a) (C) Fig. 3 (a) (b) EH'0.08mm EL2 300f71 TsubaEH-OjtnM EL=300mm f0 05 5 daO

Claims (1)

[Claims] 1. In a multi-high rolling mill in which a plurality of intermediate rolls and integral backup rolls are sequentially arranged behind a pair of work rolls, a roll group consisting of the work rolls, intermediate rolls, and backup rolls is provided. A set of at least two rolls selected from among them is given a crown with one end tapered, while a set of at least two rolls selected from the above roll group is given a crown with the same corrugation as each other. each having a roll crown extending over at least one wavelength of the curve, and for each of the above-mentioned crowning roll pairs,
A multi-high rolling mill having integrated backup rolls, characterized in that the roll axes are arranged in opposite directions and are incorporated into a mill housing so as to be movable in the roll axis direction. 2. The multi-high rolling mill according to claim 1, comprising a roll bending device.