JPH0313215A - Multistage rolling mill - Google Patents

Abstract

PURPOSE:To control the degree of flatness over a wide range by constituting a crown of rolls of the respective pairs of one pair of two pieces so that its one side end part is tapered and a waveform curve is specified, 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 end part is tapered. An intermediate roll 3 has a roll crown of a 1-pitch of a waveform curve, and both of them can be shifted in the axial direction. The pair of rolls concerned are placed so as to be opposed to each other, and shifted in the axial direction. In the case of the work roll 2, a roll gap h1 of the end part is varied to h2, and an edge drop can be adjusted. By moving the intermediate roll 3 in the axial direction, edge wave and web wave can be adjusted. By combining both of them, an excellent correction capability is obtained with respect to quarter elongation and combined elongation, as well, 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 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 f [impact force] 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.

(Problems to be Solved by the Invention) This invention advantageously satisfies the above-mentioned requirements, and further improves the shape control effect of belly extension and selvedge extension, and further improves the shape control effect of quarter extension and selvedge extension. 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 correct shape defects such as edge drops.

(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, 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 for each of the above-mentioned crowning roll pairs,
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.

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 one-wavelength waveform curve to be applied to the roll includes one pitch extracted from a sine curve, one pitch extracted from a third-order or higher-order function, and furthermore, A near-A curve is advantageously adapted, and among them, a curve taken out by one pitch from a sine curve and its near-A curve are especially advantageous.

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 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 rolls 2 are intermediate rolls 3 of 2 trees each, for a total of 4 trees, and behind the intermediate rolls 3 are split type backup rolls 4 of 3 each for the top and bottom, for a total of 6.
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 opening roll 3 is provided with a roll crown consisting of a waveform curve that can be approximated by one pitch of a sine curve. The rollers are arranged vertically so that their axial directions are opposite to each other, and have a structure that allows them to be shifted in the direction of the roll axis.

Here, 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 freely selected and assembled from all of the work roll 2 and intermediate roll 3. It is possible to match.

In addition to the above-mentioned sine curves and their approximations (or curves below), the waveform curves that should be given include waveform curves obtained by extracting one pitch across the coordinate origin from a higher-order equation of 3rd or higher order, and even its approximate curve. It may be.

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 roll pair when a pair of rolls each having a wavy roll crown that can be approximated by l bits of a sinusoidal 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 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 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 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 also 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 elongation difference Δ2 between the center and the upper end of the rolled material and the elongation difference 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.

In addition, with split backup roll extrusion, only a slight Q control can be expected for quarter elongation and alternate layer compound elongation.

Next, Fig. 5 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. 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 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 S 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 work rolls and intermediate rolls. However, each role pair is a homogeneous role group, that is, a work role pair,
More preferably, it is selected from among the group of intermediate rolls. Further, the control effect is greater as the T-crown and S-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 left-right 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. 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. 6, when the center of the roll barrel is set as the coordinate origin and a waveform curve that is point symmetrical around this origin is provided, the higher-order function is as shown in equation (1) below. .

f (x)=atx+a3x3+a3x'+ ・-+a
, x' = (1) In order to arbitrarily set the roll crown amount and pitch, it is necessary to determine the coefficients at-a, , so as to satisfy the six equations shown in Table 1.

In particular, when n = 3, that is, as shown in the following equation (1)', 3
When expressed by the following odd function, there are two unknowns, al+a3, so only two conditional expressions in equation (2) shown in Table 1 can be considered.

f (x)=a, x+a, x” ”
・(1) 'For example, in order to define the crown amount, considering formulas (2)-1 and (2)-2 shown in Table 1,
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 the above-mentioned Fig. 1 for one group, the work roll 2 includes a roll having a single tapered shape (T-crown) as shown in Fig. 7(a), and an intermediate roll. 3 can be approximated by a cubic equation as shown in Fig. 8 (31
A roll with a crown) was used.

Then, while shifting the work roll and intermediate roll in the axial direction and extruding with the split backup roll, a stainless steel plate with a width of 1000 mm is rolled into plate J! ! 1.2mm to 1. Rolled into o ram.

Shape plan views showing the roll arrangement and shape correction ability at this time are shown in FIGS. 9(a) and 9(b), respectively.

Fig. 9 also shows a case in which a conventional device is used, in which a T-crown roll as shown in Fig. 7(b) is used as an intermediate roll, and these rolls are shifted in the axial direction, and a split backup roll is used. The results of an investigation into the shape control ability when similar rolling is performed in combination with extrusion are also shown.

As is clear from FIG. 9, 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.

In the same <12-high rolling mill, as shown in Fig. 10(a), the rolled material is placed on one of two pairs of intermediate rolls that are symmetrical at the sandwiching points, and the rolling round shown in Fig. 7) is placed. (T crown)
The other intermediate roll is provided with a crown (S2 crown) that can be approximated by one pitch of the sine curve as shown in FIG. Crown that can be approximated by inches (S2
Fig. 10(b) shows the results of an investigation on the shape control ability when rolling was carried out in the same manner as in Example 1 by applying a crown) and extruding using split backup rolls.

In the same <12-high rolling mill, as shown in Fig. 12(a), the rolled material is placed on one of two pairs of intermediate rolls symmetrical at the pinching points as shown in Fig. 7(c). A round (T-crown) 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. 11 is given to the other intermediate roll, and extrusion is also performed using a split backup roll. Figure 12(b) shows the results of investigating the shape control ability when rolling similar to Example 1.
Shown below.

In the same 12-high rolling mill, as shown in Fig. 13(a), the work roll was given a round (T-crown) as shown in Fig. 7(a), and the rolled material was A crown (S1 crown) that can be approximated by a cubic equation as shown in FIG.
Figure 13 (
+1).

1 ship 1 In the same <12-high rolling mill, as shown in Fig. 14 (a), the work rolls are given a round (T-crown) as shown in Fig. 7 (a), and the upper part of the intermediate roll is The pair of left and right rolls located at Figure 14 Φ) shows the results of an investigation regarding the shape control ability when performing the following steps.

In the same 12-high rolling mill for tip twisting, as shown in Fig. 15(a)), the T-crown shown in Fig. 7(a) is attached to the pair of work rolls, and an upper and lower set of rolls sandwiching the rolled material of the intermediate roll. A crown (S2 crown) that can be approximated by one pitch of a sinusoidal curve as shown in FIG. 11 was given to each pair, and rolling was carried out in the same manner as in Example 1 using a combination of roll bending and extrusion using a split backup roll. The results of an investigation regarding the shape control ability when

Disaster Spotting 1 Same (In a 12-high rolling mill, as shown in Fig. 16 (a), the work roll has a crown (St crown) that can be approximated by the cubic equation shown in Fig. 8, In addition, all of the intermediate rolls 4 are rolls having a single taper shape (T-crown) as shown in FIG. The results of the investigation on the shape control ability when rolling are shown in the same figure (b).
).

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

[Brief explanation of drawings]

FIGS. 1(a) and (b) are a side view and a front view, respectively, showing the roll arrangement of a 12-high rolling mill to which the present invention is applied, and FIGS. 2(a) to (d) are T-crown rolls, respectively. Figure 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 Figure 4 shows a T-crown roll installed on the work roll or intermediate roll of a 12-high rolling mill. Figure 5 shows the shape control ability when a pair of rolls or a pair of S-crown rolls are applied individually. Figure 6 is an explanatory diagram of the S crown that can be approximated by a higher-order formula, Figures 7 (a) and (b) are the shape control range diagram showing the shape correction ability when using Figure 8 is a diagram showing the suitable S crown that can be approximated by a cubic equation. Figures 9 and 10 (a) and (b) are the T crown roll and S crown in a 12-high rolling mill, respectively. Roll arrangement diagram showing the arrangement of the crown roll and shape control range diagram, 1st
Figure 1 shows a suitable S crown that can be approximated by l pitch of a sinusoidal curve, and Figures 12 to 16 (a) all show the arrangement of T crown rolls and S crown rolls in a 12-high rolling mill. Both the roll arrangement diagram shown 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 device Fig. 1 (a) (b) (b) (C) Fig. 3 Fig. 6 Fig. 7 (a) E)! =θ08pnw+ EL-3oomn EL □300mm fO -0,5 5 f,0 Roll Barrel Central Rihide no Kashigen/! force r

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. and for each of the above-mentioned pairs of crowning 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.