JPH0313212A - Multistage rolling mill - Google Patents

Abstract

PURPOSE:To control the degree of flatness over a wide range by constituting a crown of a pair of two pieces of rolls, respectively so that one side end part is tapered and has a specific waveform curve, assembling them in the reverse directions, and integrating them so as to be movable in the axial direction. CONSTITUTION:A pair of work rolls 2 are placed in the upper and the lower parts by placing a rolled stock 1 between them, and as for the work roll 2, its one side edge is tapered. To one of two pairs of intermediate rolls 3, a roll crown of a 1-pitch of a waveform curve is imparted, and to the other, a roll crown of a 2-pitch or more of the waveform curve is imparted. As for the work roll 2, since its tapered part is installed in the reverse direction, when it is shifted to the axial direction, a roll gap h1 of the end part is varied to h2. The waveform crown also generates the same effect. With respect to edge wave, web wave, quarter elongation, combined elongation, and an edge drop, an excellent correction capability is obtained, and the degree of flatness can be controlled over a wide range.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a multi-high rolling mill equivalent to 12 stages having an excellent flatness control function.

(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 method is to control the shape of the rolled material by dividing the outermost backup roll into a plurality of rolls in the axial direction and adjusting the amount of displacement of each divided roll. However, in this method, there are a large number of intermediate rolls between the backup roll and the work roll (the more they exist, the more their effectiveness is diminished; A rolling mill could not fully demonstrate its capabilities.

To improve this point, the
In the above publication, a method was proposed in which a work meal bender or an intermediate roll bender was used in combination with the above-mentioned backup roll displacement adjustment method. 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.

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 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.

(Problems to be Solved by the Invention) This invention advantageously solves the above-mentioned problems, and can solve not only simple belly elongation and ear elongation, but also complex shape defects such as quarter elongation and alternate layer compound elongation. Furthermore, the purpose is to propose a multi-high rolling mill with a capacity equivalent to 20 stages, which is capable of correcting edge drops and has excellent shape control ability.

(Means for Solving the Problems) That is, the present invention provides a multi-high rolling mill in which a plurality of intermediate rolls and backup rolls are sequentially arranged behind a pair of work rolls, and a roll group consisting of the work rolls and the intermediate rolls. A set of at least two rolls selected from the above group 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 that is the same as each other. a roll crown extending over at least one wavelength of the waveform curve, and a roll crown extending over at least two wavelengths of the same waveform curve to each of at least two other rolls, and each pair of the above-mentioned crowned rolls For every,
This is a multi-stage rolling mill in which the axial directions of the rolls are arranged in opposite directions and are incorporated into a mill housing so as to be movable in the axial direction of the rolls.

The present invention also provides a multi-high rolling mill in which a roll benzo ink device is incorporated into the above rolling mill.

In this invention, the waveform curve for one wavelength or two wavelengths to be applied to the roll may be a curve obtained by extracting one pitch or two pitches from a sine curve, or a waveform curve obtained by extracting one pitch or two pitches from a sine curve, or one obtained by extracting one pitch or two pitches from a higher-order function of third or higher order. Those obtained by extracting one or two pitches from a sine curve and their approximate curves are advantageously suitable, but among them, the one or two pitches extracted from a sine curve and their approximate curves are particularly suitable.

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

FIGS. 1(a) and 1(b) do not show the side or front view of the roll arrangement of the multi-high rolling mill according to the present invention.

In the figure, 1 is a rolled material, 2 is a work roll, 3 is an intermediate roll, and 4 is a split type backup roll.A pair of work rolls 2 are arranged above and below with the rolled material 1 in between. Behind the work roll 2 are a total of 4 intermediate rolls 3, each with 2 rolls, and behind the intermediate roll 3 are a total of 6 split-type backup rolls 5, 3 each on the upper and lower sides.
are installed, and these constitute a 12-high rolling mill.

Nao, 5 is a roll bending device.

Among these, the work roll 2 has a roll crown tapered at one end, and one of the two pairs of rolls of the intermediate roll 3, which are symmetrical across the rolled material 1, has a sinusoidal curve of 1,000 minutes. A roll crown consisting of a waveform curve that can be approximated is provided, and a roll crown consisting of a waveform curve that can be approximated by two pitches of a sine curve is provided on the other side, and each has a structure that can be shifted in the roll axis direction.

Here, the rolls to which a single taper crown and a waveform curve that can be approximated by one or two pitches of a sine curve are not limited to the above examples, but can be freely selected from all of the work roll 2 and intermediate roll 3. 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 5th order or higher, or even a waveform curve thereof. 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 (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 case where a pair of rolls with a corrugated roll crown that can be approximated by l pinch of a sine curve is installed in opposite directions in the roll axis direction and shifted in the axial direction. Shows roll 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 shown in (a), and the roll gear 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 stroke of a sinusoidal curve in the roll axis direction, it is possible to effectively correct the edge elongation and belly elongation.

Next, FIGS. 4(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 2 pitches of such a sine curve in the roll axis direction, it is possible to effectively correct the quarter elongation.

Next, FIG. 5 shows a case where a pair of rolls provided with a single taper crown (hereinafter simply referred to as T-crown) is used as the work roll (WR) of the 12-high rolling mill shown in FIG. 1 above.
Furthermore, as an intermediate roll (rMR), a pair of rolls with a wavy roll crown (hereinafter simply referred to as S crown) that can be approximated by one pitch of a sine curve, or a pair of wavy roll crowns (hereinafter simply referred to as S crown) that can be approximated by two pitches of a sine curve ( Using a pair of closed rolls (hereinafter simply referred to as W-crowns), we investigated the shape control ability when each was individually shifted appropriately in the roll axis direction, and compared it with the case when a split bank-up roll was pushed out. Shown.

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 the single taper roll shift and the S-crown shift, the ear extension and belly extension can be controlled to a certain degree, but the quarter extension and the ear 1]! ? There is little hope for 1-go elongation control.

It should be noted that split buffer knob roll extrusion can only be expected to provide slight control over quarter elongation and interlayer) M 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 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 and an S-crown roll were used as intermediate rolls in the above 12-high rolling mill. A comparison will be shown with the results of the investigation when a single tapered roll is used as the roll and extrusion using a split backup roll is also used.

As is clear from the figure, by combining T-crown rolls, S-crown rolls, and W-crown rolls and shifting them appropriately in the roll axis direction, not only edge elongation and belly elongation, but also quarter elongation and compound elongation, Furthermore, an excellent ability to correct edge drops can be obtained, and flatness control over a wide range can therefore be realized.

In this invention, the pair of rolls to which the T-crown, 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 and an intermediate roll. However, it is more preferable that each pair of rolls is selected from a group of rolls of the same type, that is, a pair of work rolls and a group of intermediate rolls.

In addition, the control effect increases as the T-crown, S-crown, and W-crown imparting rolls are closer to the material to be rolled, and the arrangement of each pair of rolls is point symmetric, vertically symmetric,
Larger in order of left and right symmetry.

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-)-a, x3-+-a, x' +
-= +a, x″・” (L) (1) To arbitrarily set the roll crown amount and pitch using 2,
Coefficients 81 to a to satisfy the six equations shown in Table 1,
, it is necessary to decide.

Table 1 In other words, equation (1) has six unknowns "l+ a: l+ a
It is an 11th order odd function as shown in the following equation (1)' with 5+a7a9+all, which is extremely complicated.

f(x)=a+x+a3x3+a, x5+a-, x'+
a,x9+a,,xrow(1)' Also, when n<11, the roll crown cannot be set arbitrarily. That is (1)
“If we try to express it using a quintic odd function like the equation, there are three unknowns: all 83+85, so we can only take into account three conditional expressions out of equation (2) shown in Table 1. It is from.

f (x)=a+x+a3x' shiasxs
... (1) "For example, in order to define the crown amount, (2)-1, (2)-2 shown in Table 1
If the formula is selected, the remaining 4 are required to specify the pitch.
Conditional expression (2L3. (2)-4゜(2)-5, (2
Since only one conditional expression can be selected from )-6 and the crown pitch is uniquely determined by this, the crown pitch cannot be changed arbitrarily.

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 sine curve, the crown cannot be selected arbitrarily if the degree is low, and on the other hand, if the decision number is high, it becomes extremely complicated. Some disadvantages remain.

(Example) In the 12-high rolling mill shown in Fig. 1 above, a work roll is provided with a crown (Wl crown) that can be approximated by a quintic equation as shown in Fig. 8, and the rolled material l One of the two pairs of intermediate rolls 3, which are symmetrical across the two sides, has a crown (Sl crown) that can be approximated by a cubic equation as shown in Fig. 9, and the other intermediate roll 3 has a crown as shown in Fig. 1O. A single tapered shape (T-crown) as shown was provided.

Then, the work roll and the intermediate roll were shifted in the axial direction, and a stainless steel plate having a width of 1000 mm was rolled from a thickness of 1.2 ml11 to 1.0 m+n.

Shape plan views showing the roll arrangement and shape correction ability at this time are shown in FIGS. 11(a') and 11(b), respectively.

In addition, FIG. 11(b) shows a case where the conventional device is used, in which the single tapered rolls shown in FIG. The results of an investigation into the shape control ability when similar rolling was performed in conjunction with extrusion are also shown.

As is clear from FIG. 11(b), with the conventional device, the shape control ability can only be obtained within a narrow range, and the 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.

Tip example 1 Similarly, in a 12-high rolling mill, as shown in Fig. 12(a), a crown (Sl crown) that can be approximated by the cubic equation shown in Fig. 9 is provided on the work roll, and the rolled material is One of the two pairs of intermediate rolls, which are symmetrical at the pinch point, has a crown (Wl crown) that can be approximated by a quintic equation as shown in Figure 8.
Figure 12 shows the results of investigating the shape control ability when the other intermediate roll was given a single tapered shape (T-crown) as shown in Figure 10 and rolled in the same manner as in Example 1. Shown in (b).

In the same 12-high rolling mill as in Example 1, as shown in Fig. 13(a), each work roll has a round (T-crown) as shown in Fig. 14, and the rolled material is sandwiched between the work rolls. One of the two pairs of intermediate rolls which are point symmetrical has a 15th intermediate roll.
A crown (W2 crown) that can be approximated by two pitches of a sine curve as shown in the figure is given to the other intermediate roll, and a crown (S2 crown) that can be approximated by one pitch of a sine curve as shown in Fig. 16 is given to the other intermediate roll. 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. 17(a), the work roll is given a crown (S2 crown) that can be approximated by the sinusoidal curve 1 pin 1000 shown in Fig. 16,
In addition, one of the 2m intermediate rolls that form a pair on the upper and lower sides has a 15th
A crown that can be approximated by 2 pitches of a sine curve (W2 crown) as shown in the figure, and a round (T crown) as shown in Figure 10 are given to the other,
Figure 17 (b
).

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

[Brief explanation of the drawing]

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. Figures 3 (a) to (C
) are diagrams showing changes in the roll gap when S crown rolls are installed parallel to each other in opposite directions and shifted in the roll axis direction, and Figures 4 (a) to (C) are diagrams showing changes in the roll gap when the W crown rolls are installed in reverse and parallel to each other and shifted in the roll axis direction. Figure 5 shows the roll gap change when the roll is installed parallel to the roll axis and shifted in the roll axis direction.
The figure shows the shape control ability when a T-crown roll pair, an S-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. , a T crown roll as a work roll of a 12-high rolling mill, and a W as an intermediate roll.
Figure 7 is a shape control range diagram showing the shape correction ability when the crown roll and S crown roll are used at the same time.
An explanatory diagram of a W crown that can be approximated by a higher-order formula. Figure 8 shows a suitable W crown that can be approximated by a quintic formula. Figure 9 shows a suitable S crown that can be approximated by a cubic formula. Figure 10 is a diagram showing the tapered shape of a single tapered roll, Figures 11 (a) and (b) are the arrangement of the T-crown roll, W-crown roll, and S-crown roll in a 12-high rolling mill, respectively. 12.13 (a) and (b) are roll arrangement diagrams showing the arrangement of T crown rolls, W crown rolls, and S crown rolls in a 12-high rolling mill, respectively; Shape control range diagram, Figure 14 is a diagram showing the taper shape of a single tapered roll, Figure 15 is a diagram showing a suitable W crown that can be approximated by two pitches of a sine curve, and Figure 16 is a diagram showing a sine curve. 17(a) is a roll arrangement diagram showing the arrangement of a T-crown roll, a W-crown roll, and an S-crown roll in a 12-high rolling mill. (1)) is a shape control range diagram for each roll arrangement shown in FIG. 3(a). 1... Rolled material 2... Work roll 3.
...Intermediate roll 4...Back unroll 5
... Roll benzo ink device (a) (b) Figure 1 Figure 4 (a) (b) (C) Figure 3 (a) (b) (C) -1,0 -0,500,5 0 - Lack of heat in barrel central force ゛~・ 0 Fig. 7 shows lack of fuel Fig. 10 EH = 0.177 + 1 EL = 300? ? 14th figure EH=o, ogada EL 300mm

Claims (1)

[Claims] 1. In a multi-high rolling mill in which a plurality of intermediate rolls and backup rolls are sequentially arranged behind a pair of work rolls, at least one roll selected from a group consisting of the work rolls and intermediate rolls, A set of two rolls is provided with a crown tapered at one end, while a set of at least two other rolls also selected from the above roll group is provided with at least one wavelength of the same waveform curve. a roll crown extending over at least two wavelengths of the same waveform curve to another set of at least two rolls;
A multi-stage rolling mill characterized in that the axial directions of the rolls are arranged in opposite directions and are incorporated into a mill housing so as to be movable in the axial direction of the rolls. 2. The multi-high rolling mill according to claim 1, comprising a roll bending device.