JPH0313209A - Multistage rolling mill having integral type backup roll - Google Patents

Abstract

PURPOSE:To control flatness over a wide range by imparting roll crown curved to the waveform of one wavelength to one set of rolls and the roll crown curved to the waveform of two wavelengths 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 curved to the waveform of one wavelength 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 the back up rolls 4, 4 of the multistage rolling mill. The roll crown curved to the waveform of two wavelengths is imparted to 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 excellent ability to correct quarter waviness and combined waviness is obtd. 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, the effectiveness of this method is diminished the more intermediate rolls are present between the backup roll and the work roll. I was not able to fully demonstrate my 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 range in which the control force is applied is only around a part of the taper, and furthermore, it is complicated because the taper shape must be changed one by one depending on the steel type, plate width, etc.

In addition, special public service in Showa 63. ．． Publication No. 30104 and the like propose a vertically arranged rolling mill 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. However, even with this method, only the ends and center of the rolled material could be controlled, and it was powerless to control quarter elongation, as well as compound elongation in which belly elongation, edge elongation, etc. were mixed.

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

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

(Problems to be Solved by the Invention) This invention advantageously solves the above problems, and corrects complex shape defects such as quarter elongation and alternate layer compound elongation, as well as simple belly elongation and ear elongation. The purpose of the present invention is to propose a multi-high rolling mill equivalent to 12 stages, which has excellent shape control ability and can apply a sufficiently high rolling load.

(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 rolls selected from a group of rolls consisting of rolls (both rolls are given a roll crown with the same waveform curve (both of which span one wavelength); A set of at least two rolls is provided with a roll crown extending over at least two wavelengths of the same waveform curve, and for each pair of the above-mentioned crowned rolls,
This is a multi-high rolling mill having integral backup rolls arranged so that the roll axes are opposite to each other and built into a mill housing so as to be movable in the roll axis direction.

Further, the present invention is a multi-high rolling mill in which a roll pending device is incorporated in the above-mentioned rolling mill.

In this invention, the one-wavelength or two-wavelength waveform curve to be applied to the roll includes one pitch or two pitches extracted from a sine curve, and one pitch derived from a third or higher order function. A curve obtained by extracting one or two pitches from a sine curve and an approximate curve thereof are advantageously suitable, but a curve obtained by extracting one pitch or two pitches from a sine curve and an approximate curve thereof are especially suitable.

The present invention uses a combination of roll pairs provided with crowns extending over at least one wavelength and two wavelengths of the waveform curve described above, thereby significantly improving shape control ability compared to the conventional method, as described later. This eliminates the need for shape control through extrusion of split backup rolls, which was indispensable for conventional multi-high rolling mills, and makes it possible to use an integrated backup roll. The use of a backup role is achieved for the first time in this invention.

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

Figures 1(a) and 1) show the roll arrangement of a multi-high rolling mill according to the invention from the side and from the front.

In the figure, 1 is a rolled material, 2 is a work roll, 3 is an intermediate roll, and 4 is an integrated backup roll.A pair of work rolls 2 are arranged above and below with the rolled material 1 in between. A total of four intermediate rolls 3, two each, are installed behind the work rolls 2, and a total of six integrated bank-up rolls 4, three each on the upper and lower sides, are installed behind the intermediate rolls 3. This constitutes a 12-high rolling mill.

Note that 5 is a roll pending device.

Among these, the work roll 2 is provided with a roll crown consisting of a waveform curve that can be approximated by one pitch of a sine curve, and has a structure that can be shifted in the roll axis direction.

On the other hand, the intermediate roll 3 and the backup roll 4 indicated by diagonal lines in FIG. It has become.

The rolls to which a waveform curve that can be approximated by one pitch or two pitches of a sine curve is not limited to the above cases, but can be freely selected from among the work rolls 2, intermediate rolls 3, and backup rolls 4. Selection and combination are possible.

In addition to the above-mentioned sine curve and its approximation curve, the waveform curve to be provided is a waveform curve obtained by extracting one pitch or two pitches across the coordinate origin from a higher-order equation of third order or higher, and furthermore, It may be an approximate curve.

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

(Function) As shown in Fig. 2 (a) to (C), when a pair of rolls with a waveform 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. The figure shows the change in roll gap at .

FIG. 5A shows a case where the pair of rolls are arranged facing each other and the roll gap is constant in the axial direction. The figure 0)) is
This is a case where each roll is moved in the direction of the arrow from the state shown in (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 l pitches of such a sinusoidal curve in the roll axis direction, it is possible to effectively correct the edge elongation and the belly elongation.

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 two pitches 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. The same figure (c) is
This is a case where each roll is moved in the direction of the arrow from the state of (a), and the roll gap is narrow in part of the quarter and wide in the center and both ends. In addition, in FIG. 3C, each roll is moved in the opposite direction to that in FIG.

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

Further, FIG. 4 shows a comparison of the maximum additional rolling loads when using a conventional split type backup roll and an integral 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.

Figure 5 shows a corrugated roll crown (hereinafter simply referred to as S crown) that can be approximated by one pitch of a sine curve as a work roll (WR) or intermediate roll (IMR) of the 12-high rolling mill shown in Figure 1 above. Shape control when a pair of rolls with a wavy roll crown (hereinafter simply referred to as W crown) that can be approximated by one pitch of a sine curve is used, and each is shifted appropriately in the roll axis direction. The results of the investigation on capacity are shown in comparison with the case where a so-called single tapered roll, which is tapered and ground on one side, is shifted and the case where a split backup roll is extruded.

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 single taper roll shift and S-crown shift, although the edge elongation and belly elongation can be controlled to a certain degree, quarter elongation and alternating layer composite elongation control cannot be expected much.

It should be noted that split backup roll extrusion can only be expected to provide slight control over quarter elongation and alternate layer joint elongation.

On the other hand, in the case of W crown shift, significant effects can be expected in terms of quarter elongation and alternating layer composite elongation control. However, it cannot be said that the control of ear extension and belly extension is sufficient.

Next, FIG. 6 shows the S crown roll as the work roll and the W as the intermediate roll in the above 12-high rolling mill.
The results of an investigation into the shape modification ability when a crown roll is used at the same time are shown in comparison with the findings when a single tapered roll is used as an intermediate roll and extrusion by a split backup roll is also used.

As is clear from the figure, by combining the S-crown roll and the W-crown roll and shifting the rolls appropriately in the axial direction, not only the edge elongation and belly elongation can be achieved.
Excellent correction ability is obtained for quarter elongation and even compound elongation, and therefore flatness control over a wide range can be realized.

In this invention, the pair of rolls to which the S 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 S crown and W crown imparting rolls are closer to the material to be rolled, and the arrangement of each pair of rolls is larger in the order of point symmetry, vertical symmetry, and horizontal symmetry with the material to be rolled as the center.

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. However, in the case of a high-order function curve, the amount of roll crown and the pitch of the waveform can be set arbitrarily as described below. In addition to the fact that it may not be possible to set it, there are some disadvantages in that if you try to set it arbitrarily, it will be significantly more complicated than following a sinusoidal curve, and furthermore, the symmetry in the width direction is not very good.

That is, for example, if we consider the case where a waveform curve for two pitches as shown in FIG. Since it needs to be point symmetric, the higher-order function is as shown in equation (1) below: f(x)=a, x+asx"+a5x'+ ・-+an
X''++ (1) In order to arbitrarily set the roll crown amount and pitch using the formula (1), determine the coefficients a, ``+'a,'' so as to satisfy the six equations shown in Table 1. There is a need.

Table 1 In other words, equation (1) has six unknowns al+ al al
11 as in the following equation (1)' with at+a91 al
It becomes the following odd function, which is extremely complicated.

f(x)=asx+a, x3+a5x'+a, x'+a
, x''+a口xl'・''(1)' Also, if it is null, the roll crown cannot be set arbitrarily. That is (1)
When trying to express it with a 5th order odd function like the formula #, there are three unknowns: al + a3 + a, so only three conditional expressions out of formula (2) shown in Table 1 can be taken into consideration. Because you can't.

f(x)=a, x+a, x'+aSx'
=(1)"For example, in order to define the crown amount, if formula (2L1.(2)-2) shown in Table 1 is selected, in order to define the pitch, the remaining four conditional formulas (2)-, 3
, (2)-4° (2)-5, (2)-6, and only one conditional expression can be selected, which uniquely determines the crown pitch, so the crown pitch can be changed arbitrarily. This means that it will no longer be possible to do so.

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 the above-mentioned Fig. 1 with two boats, the intermediate roll 3 and the backup roll indicated by diagonal lines in Fig. 1 were constructed using a cubic formula as shown in Fig. 8. A crown that can be made (
A roll having a crown (SL crown) was used, and a roll having a crown (W1 crown) that can be approximated by a quintic equation as shown in FIG. 9 was used as the work roll 2.

Then, by shifting the intermediate roll in the axial direction, the stainless steel plate with a plate width of 1000 was changed from a plate thickness of 1.2 to 1.0.
It was rolled to 1111n.

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

Furthermore, FIG. 10(b) shows a case where a conventional device is used, in which rolls having a tapered shape as shown in FIG. 11 are used as intermediate rolls, and these rolls are shifted in the axial direction and a split bar is・The results of an investigation into the shape control ability when similar rolling was performed using extrusion using NCU-A-MP roll are also shown.

As is clear from FIG. 10(g)), 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, it is possible to obtain a wide range of control that can sufficiently handle compound elongation and quarter elongation, and it becomes possible to obtain a plate with a good shape.

In a 12-high rolling mill on the Jfill side, a roll having a crown (Wl crown) that can be approximated by the quintic formula shown in Fig. 9 was used as an intermediate roll and a backup roll, and a work roll pair was shown in Fig. 8. Each roll having a crown (31 crowns) that can be approximated by a cubic equation is
Figure 2(a) shows the results of an investigation on the shape control ability when rolling was performed in the same manner as in the example work with the arrangement as shown in Figure 2(a).
Shown in b).

As is clear from FIG. 12(b), even when the S crown roll is used as the work roll closer to the material to be rolled, excellent quarter elongation and composite elongation control ability can be obtained as in Example 1. It is being

In the same <12-high rolling mill, the work roll pair is a roll with a crown (W2 crown) that can be approximated by two sinusoidal pitches as shown in Fig. 13, while the intermediate roll and backup roll are shown in Fig. 14. Regarding the shape control ability when rolling is performed in the same manner as in Example 1 by arranging a machining hole having a crown (S2 crown) that can be approximated by one pitch of a sine curve as shown in Fig. 15(a). The results of the survey are shown in the same figure.

As is clear from FIG. 15(b), when the roll is provided with a crown approximated by a sinusoidal curve, even better quarter elongation and composite elongation control ability than in Example 1 are obtained.

In a 12-high rolling mill, a crown (which can be approximated by the cubic equation shown in Fig.
The other roll has a crown (Wl crown) that can be approximated by the quintic equation shown in FIG. 9, and the work roll pair has a crown (Wl crown) that can be approximated by the cubic equation shown in FIG. ) with the 16th roll
Figure (b) shows the results of investigating the shape control ability when rolling was performed in the same manner as in Example 1 with the arrangement as shown in Figure (a).
).

In the same <12-high rolling mill, as shown in Fig. 17(a), the rolled material is rolled onto one of the intermediate rolls symmetrical to the clamping point by two pitches of the sinusoidal curve shown in Fig. 13. The crown that can be approximated (W2 crown) and the crown that can be approximated by one pitch of the sine curve shown in FIG.
Figure 2) shows the results of an investigation into the shape control ability when rolling was carried out in the same manner as in Example 1 using a roll bender.

Implementation General I In the same <12-high rolling mill, as shown in FIG. 18(a), a crown ( W
1 crown), and the work roll pair was given a crown (31 crown) that can be approximated by the cubic equation shown in Fig. 8, and rolling was performed in the same manner as in Example 1 using a roll bender. The results of the investigation regarding the shape control ability are shown in Figure 0)).

In the same <12-high rolling mill, as shown in Fig. 19 (a), the rolled material is approximated by two pitches of the sinusoidal curve shown in Fig. 13 on one of the intermediate rolls that is symmetrical at the clamping point. A crown (W2 crown) that can be obtained and a crown (32 crown) that can be approximated by one pitch of the sine curve shown in FIG. The results of an investigation into the shape control ability are shown in FIG. 2(b).

In the same 12-high rolling mill as shown in Fig. 20(a), a crown which can be approximated by the quintic equation shown in Fig. 9 is placed on one of the backup rolls which is symmetrical about the pinching point of the rolled material. (W
1 crown) and the other a crown (S2 crown) that can be approximated by one pitch of the sine curve shown in FIG. The results of the investigation regarding control ability are shown in Figure Φ).

As is clear from FIG. 10), even when the backup roll furthest from the rolled material is provided with S and W crowns, a shape control ability equal to or greater than that of the conventional method can be obtained.

(Effects of the Invention) Thus, according to the multi-high rolling mill according to the present invention, it is possible to obtain excellent correction ability for not only edge elongation and belly elongation, but also quarter elongation and compound elongation, and therefore flatness control over a wide range is possible. can be realized.

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

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are a side view and a front view showing the roll arrangement of a 12-high rolling mill to which the present invention is applied, respectively, and FIGS. 2(a) to (C) are S crown rolls, respectively. Figure 3 (a) to (C
) are diagrams showing roll gap changes when W crown rolls are installed parallel to each other in opposite directions and shifted in the roll axis direction, and Figure 4 shows a conventional split backup roll or an integrated backup roll according to the present invention. Comparison diagram of maximum additional rolling load when using rolls, 5th
The figure shows the shape control ability when an S crown roll pair or a W crown roll pair is applied individually to the intermediate roll or work roll of a 12-high rolling mill. Figure 7 is a shape control range diagram showing the shape correction ability when a W crown roll and an S crown roll are used simultaneously as intermediate rolls and work rolls. Figure 7 is an explanatory diagram of the W crown that can be approximated by a higher-order formula. , Figure 9 is a diagram showing a suitable S crown that can be approximated by a cubic formula, Figure 9 is a diagram showing a suitable W crown that can be approximated by a quintic formula, and Figures 10 (a) and (b) are 12-high rolling. A roll arrangement diagram and a shape control range diagram showing the arrangement of the W crown roll and S crown roll in the machine, Figure 11 is a diagram showing the taper shape of the single tapered roll, and Figures 12 (a) and (b) are 13 is a roll arrangement diagram and a shape control range diagram showing the arrangement of a W crown roll and an S crown roll in a 12-high rolling mill, respectively; FIG. 13 is a diagram showing a suitable W crown that can be approximated by two pitches of a sinusoidal curve; The figure shows a suitable S crown that can be approximated by a sinusoidal epitome, and (a) in Figs. 15 to 20 all show the arrangement of the W crown roll and the S crown roll in a 12-high rolling mill. Both the layout diagram and FIG. 1... Rolled material 2... Work roll 3.
...Intermediate roll 4...Backup roll 5
...Roll benzo ink device Figure 1

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 the rolls is provided with a roll crown extending over at least one wavelength of the same waveform curve, while a set of at least two rolls selected from the group of rolls is provided with a roll crown extending over at least one wavelength of the same waveform curve. Applying a roll crown extending over at least two wavelengths of the same waveform curve, and for each pair of the above-mentioned crowning rolls,
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 pending device.