JPH0313210A - 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 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 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 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 edge drop 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 and the roll barrel becomes longer (the pending force does not act all the way to the center), the control force remains only at the ends of the rolled material. was there.

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 in that the shape of the taper must be changed one by one depending on the type of preparation, the width of the sheet, and the like.

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.

However, even with this method, only the ends and center of the rolled material can be controlled, and quarter elongation, as well as compound elongation including belly elongation and edge elongation, can be controlled.
Regarding ■, I was almost powerless.

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, and the eccentric mechanism is complicated, making mill design difficult and equipment costs high. I had left it behind.

(Problems to be Solved by the Invention) This invention advantageously solves the above-mentioned problems, and is capable of solving complex shape defects such as ear elongation, belly elongation, quarter elongation, and alternate layer compound elongation, as well as edge drops. The purpose of the present invention is to propose a multi-high rolling mill equivalent to 12-high rolling mills, which has excellent shape control ability that allows correction of the shape of the rolling stock, and is capable of applying 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 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 two wavelengths 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 two integral backup rolls, possibly integrated into the mill housing.

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

In this invention, the waveform curve for two wavelengths to be applied to the roll includes one obtained by extracting two pitches from a sine curve, a curve corresponding to two pitches extracted from a higher-order function of fifth order or higher, and furthermore, The approximation curve is advantageously suitable, but among them, the one obtained by extracting two pitches from the sine curve and the approximation curve thereof are particularly suitable.

This invention utilizes a combination of a pair of rolls each having a crown and a single taper extending over at least two wavelengths of the waveform curve as described above, and as will be described later, the ability to control the shape is significantly improved compared to the conventional method. This eliminates the need for shape control through extrusion of split backup rolls, which was indispensable in conventional multi-high rolling mills, and makes it possible to use an integrated backup roll. The use of rolls is 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, 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. Behind the work rolls 2 there are 4 intermediate rolls 3, 2 each, and behind the intermediate rolls 4 there are 6 integral 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, the work roll 2 is provided with a roll crown that is tapered at one end, and the intermediate roll 3 is provided with a roll crown that consists of a waveform curve that can be approximated by two pitches of a sine curve, and each can be shifted in the roll axis direction. It has a structure.

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

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 two pitches across the coordinate origin from a higher-order equation of 5th order or higher, or even an approximate curve thereof. It's okay.

The Sarani roll shifting 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 plate edge 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, reducing edge drop. Control can be performed 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 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 figure (b) is
This is a case where each roll is moved in the direction of the arrow from the state of (a), and a part of the quarter becomes a roll gap that becomes narrower. In addition, in FIG. 3(C), each roll is moved in the opposite direction to that in FIG. 3(b), but a part of the quarter is a wide roll gap.

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

Further, 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 integral 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 W crown) that can be moved close to each other by two sinusoidal pitches, we investigated the shape control ability when each roll was individually shifted appropriately in the roll axis direction. is shown in comparison with the case where a split backup roll is extruded.

The shape control ability was evaluated by the elongation difference Δ2 between the center and the ends of the rolled material and the elongation difference A4 between the center and a part of the quarter.

As is clear from the figure, in the case of a single taper roll shift, the shape of the edge extension and belly extension can be controlled.

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.

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

Next, Fig. 6 shows the results of an investigation into the shape correction ability when a T-crown roll was used as a work roll and a W-crown roll was used as an intermediate roll in the above-mentioned 12-high rolling mill. A comparison will be shown with the results of the investigation when a roll is used and extrusion using a split backup roll is also used.

As is clear from the figure, by combining T-crown rolls and W-crown rolls and shifting them appropriately in the roll axis direction, it is possible to achieve not only edge elongation and belly elongation, but also quarter elongation and compound elongation, as well as edge drop. Excellent correction ability is also obtained for the flatness, and therefore flatness control over a wide range can be realized.

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, if we consider the case where a waveform curve for two pitches as shown in FIG. Since it is necessary to have point symmetry, the higher-order function is as shown in equation (1) below.

f(x)=a+x+asx'+asx'10...-+aa
x' - (1) In order to arbitrarily set the roll crown amount and pitch using the (1) formula, the 6 shown in Table 1
It is necessary to determine the coefficients a1 to a1 so as to satisfy the following equations.

Table 1 In other words, equation (1) has six unknowns al, a3. a5
．． aq.

It becomes an 11th order odd function as shown in the following equation (1)' with all all, and is extremely complicated.

f (x)-a+x +a3x" 1 asx' +a7
x' + aq This is because there are three unknowns, all and alla, so only three conditional expressions out of equation (2) shown in Table 1 can be taken into consideration.

f(x)=a, x+a3x"+aSx'
=(1)'For example, to define the crown amount,
(2) to 1 shown in Table 1. (2)-If you select formula 2,
In order to define the pitch, the remaining four conditional expressions (2) −
3, (2) - 4° (2) - 5, (2L6 Only one conditional expression can be selected from among them, and the crown pitch is uniquely determined by this, so it is not possible to arbitrarily change the crown pitch. I can't (that's why)

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 Figure 1 above, the work roll 2 includes a roll having a single taper shape (T-crown) as shown in Figure 8(a), and an intermediate roll. 3 and the outer backup roll 4, rolls having a crown (Wl crown) that can be approximated by a quintic equation as shown in FIG. 9 were used.

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

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

Furthermore, Fig. 10(b) shows a case where a conventional device is used, in which T-crown rolls as shown in Fig. 8(b) are used as intermediate rolls, these rolls are shifted in the axial direction, and a split backup is performed. The results of an investigation into the shape control ability when similar rolling was performed using roll extrusion are also shown.

As is clear from FIG. 10(b), 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 apparatus of the present invention is used, it is possible to obtain a wide control range 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 with the same 1° rolling mill, as shown in Fig. 11(a), the rolled material is placed between one of two pairs of intermediate rolls that are symmetrical at the pinching point and two pairs of back-up rolls that are also symmetrical at the point. One side of the roll is given a crown (W2 crown) that can be approximated by two pitches of a sine curve as shown in Figure 12, and the work roll is given a round (T crown) as shown in Figure 8(a). Figure 11 (b) shows the results of investigating the shape control ability when rolling similar to Example 1
).

In the same 12-high rolling mill, as shown in Fig. 13(a), the rolled material is rolled on one of two pairs of intermediate rolls which are symmetrical at the clamping point, and a sinusoidal curve as shown in Fig. 12 is applied. A crown that can be approximated by two pitches (W2 crown), and a round (T crown) as shown in Fig. 8(a) on the work roll.
Fig. 13 et al.) show the results of an investigation on the shape control ability when rolling was performed in the same manner as in Example 1.

In a 12-high rolling mill, as shown in Figure 14(a), the rolled material is placed between one of two pairs of intermediate rolls symmetrical at the pinching point and the work roll as shown in Figure 9. A crown (Wl crown) that can be approximated by a quintic equation is provided, and an eighth
Figure 14 shows the results of an investigation into the ability to modify the shape when a round (T-crown) as shown in Figure (b) was applied and rolling was performed in the same manner as in Example 1.

In the same 12-high rolling mill as shown in Fig. 15(a), the work roll was given a round (T-crown) as shown in Fig. 8(a), and the rolled material was One of the two outer pairs of backup rolls that are symmetrical at the sandwiching point is given a crown (Wl crown) that can be obtained using a quintic formula as shown in FIG. FIG. 15(b) shows the results of an investigation regarding the shape control ability during rolling.

In the same <12-high rolling mill, as shown in Fig. 16(a), the work rolls are given a round (T-crown) as shown in Fig. 8(a), and all the backup rolls are Fig. 12 shows the results of an investigation on the shape control ability when rolling was performed in the same manner as in Example 1 by adding a crown (W2 crown) that can be approximated by two sinusoidal pitches as shown in Fig. 12. Φ).

In a 12-high rolling mill, as shown in Fig. 17(a), one of the two pairs of intermediate rolls that are symmetrical about the pinching point of the rolled material and the two outer pairs of back-up rolls that are similarly symmetrical are used. A crown (W2 crown) that can be approximated by two pitches of a sine curve as shown in Figure 12 is given to one of the rolls, and a T-crown as shown in Figures 8 (b) and (C) is given to the remaining rolls. The results of investigating the shape control ability when rolling was performed in the same manner as in Example 1 are shown in FIG.
Shown below.

In a 12-high rolling mill, as shown in Fig. 18 (a), the rolled material is placed on one of two pairs of intermediate rolls that are symmetrical at the nipping point, and the quintic formula shown in Fig. 9 is applied. The remaining rolls were each given a T-crown (Wl crown) that can be approximated by , and a T-crown as shown in Fig. 8(b) was applied to the remaining rolls. The results of an investigation into the shape control ability of the 3D 3D are shown in FIG. 2B.

In the same <12-high rolling mill, as shown in Fig. 19(a), the rolled material is placed on one of the two outer pairs of intermediate rolls symmetrical at the clamping point. A crown (Wl crown), which can be obtained using the following formula, is attached to the remaining roll in Fig. 8 (C
) shows the results of an investigation on the shape control ability when rolling was performed in the same manner as in Example 1 using a roll bender in combination with the T-crowns shown in Figure 1 (b).

(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 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 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 changes in the roll gap when W crown rolls are installed parallel to each other in opposite directions and shifted in the roll axis direction, and Figure 4 shows the conventional split type back unroll or the integrated type according to the present invention. Comparison diagram of maximum additional rolling load when using backup rolls, Part 5
The figure shows the shape control ability when a T-crown roll pair or a W-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 a W crown roll and a T crown roll are used simultaneously as the work roll and intermediate roll, respectively. a) to (C) are diagrams each showing the tapered shape of a single tapered roll, FIG. 9 is a diagram showing a suitable W crown that can be approximated by a quintic equation, and FIG. 10.11 (a), et al. ) are a roll arrangement diagram and a shape control range diagram showing the arrangement of a T crown roll and a W crown roll in a 12-high rolling mill, respectively.
The figure shows a suitable W crown that can be approximated by two pitches of a sinusoidal curve. Figures 13-19 (a) all show the arrangement of T-crown rolls and W-crown rolls in a 12-high rolling mill. Both the roll layout diagram and (b) of the same figure are
It is a shape control range figure in each roll arrangement of the same figure (a). 1... Rolled material 2... Work roll 3.
...Intermediate roll 4...Backup roll 5
...Roll bending equipment Figure 1 (a) (b) Figure 3 (b) (C) Figure 8 EL = 300m -1,0 -0,500,5 0-Rhal central force ゛5 's Netsugumo Genzatan f, 0

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 two wavelengths 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.