JPH05245506A - 6-stage rolling mill - Google Patents

Abstract

PURPOSE:To prevent degradation of rigidity and meandering and to execute stable rolling by composing rolls so that the barrel ends at the time of the max. and the min. shift of intermediate rolls which are shiftable in the axial direction are protruded outside the barrel ends of back-up rolls. CONSTITUTION:In a 6-stage rolling mill which is provided with respective pairs of upper and lower rolls of work rolls 2, intermediate rolls 3 and back-up rolls 4 and of which at least the intermediate rolls 3 of respective intermediate rolls 3 and work rolls 2 are made shiftable in the axial direction, each of the intermediate rolls has a barrel length longer than the barrel length of the back-uproll 4 so that its barrel ends are protruded outside the barrel ends of the back-up roll 4 even at the time of the max. and the min. positions and then that pair of intermediate rolls are composed so as to have roll crowns that are vertically in point symmetric. Thus, control of sheet crown and reduction of edge drop can be attained, degradation of the rigidity of rolling mill and meandering of rolled stock are prevented and roll life can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling mill, especially a hot finishing mill for rolling a sheet bar rolled by a rough rolling mill to a product thickness, or a coil obtained by the hot finishing rolling. The present invention relates to a 6-high rolling mill used as a cold rolling mill for rolling, in particular, with high precision control of a sheet culan defined as a sheet thickness difference between a sheet width center portion and a portion near an edge, and further at a sheet edge portion. This is also for realizing the reduction of the edge drop which becomes extremely thin.

[0002]

2. Description of the Related Art Generally, when a hot-rolled steel sheet is manufactured by a hot finish rolling mill, the roll is bent by a rolling load, so that the plate thickness at the edge portion is larger than that at the central portion of the width. It becomes thinner than the thickness and a plate crown is generated there. This plate crown, when they become large, in the cold rolling of the next step, it becomes difficult to bring about an appropriate plate profile, and a defective shape is likely to occur, so that the yield is unavoidably reduced. Particularly in a hot finish rolling mill, it is necessary to make the plate crown as small as possible.

On the other hand, since cold rolling is performed at room temperature, the deformation resistance of the plate is large and the rolling load is large as compared with the hot rolling, so that the edge drop of the plate becomes extremely thin, especially the edge drop. Is likely to occur. Therefore, the rolling mill used for cold rolling is also required to have a function of avoiding the generation of edge drops.

As a technique aiming at controlling the shape of a plate, for example, for the purpose of reducing the plate crown, Japanese Patent Publication No.
No. 2-10722, an intermediate roll consisting of a so-called flat roll having a uniform diameter over the entire length of the roll is disposed between the backup roll and the work roll, and both intermediate rolls are arranged in the axial direction thereof. There is disclosed a rolling mill train in which a crown controllability is enhanced by installing a 6-high rolling mill capable of shifting in opposite directions to each other on a rear stand. Further, in Japanese Patent Application Laid-Open No. 57-91807, an S-shaped crown is provided on either a work roll, an intermediate roll or a backup roll, and the roll having the S-shaped crown is axially shifted. Rolling mills with improved crown control have been proposed.

[0005]

However, in the technique disclosed in Japanese Patent Publication No. 62-10722,
Since the length of the intermediate roll is about the same as the length of each of the backup roll and the work roll, when the intermediate roll is shifted to reduce the plate crown, the intermediate roll, the backup roll and the work roll Since the contact length with the roll becomes short and the vertical rigidity of the rolling mill decreases, when the rolling load changes due to the temperature deviation of the sheet bar and other factors, the roll gap of the work roll changes significantly, and the specified plate thickness accuracy There is a problem that can not bring about
When the center of the strip width deviates from the center of the rolling mill, there is a problem that meandering occurs due to the difference in rigidity between the left and right sides of the rolling mill, and rolling becomes impossible due to narrowing.

In addition, when the intermediate roll is shifted, since the contact length with other rolls is short, spalling occurs due to the increase in the linear pressure between the rolls, and the life of the rolls is shortened early. There was another problem of doing it. The above problem can be avoided by reducing the shift amount of the intermediate roll, but naturally the crown controllability of the rolling mill is limited to an extremely narrow range.

Next, in the latter prior art disclosed in Japanese Patent Laid-Open No. 57-91807, for example, when profile control is performed by shifting a work roll having an S-shaped crown, the work roll is used. There was a problem that the crown control became impossible due to the abrasion of the.

Further, when a curved roll crown is applied to the intermediate roll or the backup roll to control the plate profile, it is necessary to increase the roll crown in order to obtain a large crown control amount. When rolling a sheet bar with a narrow strip width and a small rolling load, a non-contact part occurs between the intermediate roll and the backup roll or between the work roll and the backup roll, which reduces the vertical rigidity of the rolling mill and reduces the strip thickness accuracy. Will end up. Further, the occurrence of the non-contact portion may cause a difference in rigidity in the roll axis direction of the rolling mill, and may cause meandering or drawing of the plate to cause unrolling.

On the other hand, regarding the reduction of the edge drop, JP-A-55-77903 discloses controlling the shift amount of a work roll having a tapered end, but the reduction of the edge drop is not found. However, profile control over the entire width of the plate is impossible.

The present invention solves all of the problems of the prior art, enables the control of the plate crown and the reduction of edge drop, and in particular reduces the rigidity of the rolling mill due to the large shift of the intermediate roll. Further, the present invention provides a 6-high rolling mill that prevents the rolling material from meandering and also achieves a longer roll life.

[0011]

According to the present invention, a pair of upper and lower work rolls, an intermediate roll and a backup roll are provided, and at least the intermediate roll of the respective intermediate rolls and work rolls can be shifted in the axial direction. In the six-high rolling mill, each intermediate roll has a barrel length longer than the barrel length of the backup roll, the barrel end of which can project outside the barrel end of the backup roll even in the maximum and minimum shift positions. In addition, the intermediate roll pair is a 6-high rolling mill having roll crowns that are point-symmetrical in the vertical direction.

Here, the barrel length of the intermediate roll is 1.2 to 2.5 times the barrel length of the backup roll, and the barrel length of the work roll is longer than the barrel length of the intermediate roll, preferably the barrel length of the backup roll. The length of 1.4 to 2.5 times is advantageous for implementation.

The roll crown of the intermediate roll is S
Any one selected from a letter shape, a taper shape that gradually decreases in diameter toward one end of the barrel, and a double taper shape that gradually decreases in diameter toward both ends of the barrel are suitable. Here, the S-shaped roll crown is one obtained by extracting one pitch from a higher-order function curve of third or higher order, one pitch extracted from a sine function curve, or a curve approximate to those curves. A roll crown made of any of the above.

Further, the work roll is provided with a roll crown having a taper gradually decreasing toward one end of the barrel or a double taper gradually decreasing toward both ends of the barrel. A 6-high rolling mill can be configured by appropriately combining with any of the above-described intermediate rolls provided with a roll crown.

[0015]

In the six-high rolling mill of the present invention, by imparting the roll crown to the intermediate roll, the load acting between the rolls, especially between the intermediate roll end and the work roll end is reduced. The crown controllability can be improved. Especially, according to the S-shaped roll crown,
Effectively reduces the rolling load acting on the side edges of the plate, which becomes more remarkable when the respective intermediate rolls are point-symmetrically shifted in opposite directions, and the crown controllability is increased. Hope to improve.

In this rolling mill, since the barrel length of the intermediate roll is longer than the barrel length of the backup roll, even if the shift amount of the intermediate roll is increased, the length of the backup roll is always and reliably maintained. Since the intermediate rolls come into contact with each other, it is possible to very effectively prevent the reduction of the vertical rigidity of the rolling mill due to the profile control, and therefore the plate thickness accuracy is sufficient without being affected by the fluctuation of the width of the rolled plate. In addition, even if there is a bend in the rolled plate, it is possible to effectively reduce the occurrence of meandering by rolling it evenly over the entire width.

When the barrel length of the intermediate roll is about the same as the barrel length of the backup roll, the maximum and minimum diameter difference of the intermediate roll provided with the roll crown is increased in order to obtain the required crown control amount. There is a need. Then, since the linear pressure between rolls increases, spalling may occur and roll life may be shortened. Furthermore, when the width of the rolled plate is relatively narrow and the rolling load is small, a non-contact area is generated between the intermediate roll and the inside of the backup roll or the barrel of the work roll. The problem that thickness accuracy cannot be obtained may occur. Therefore, in order to wipe out these concerns, it is preferable to set the barrel length of the intermediate roll to 1.2 to 2.5 times the barrel length of the backup roll.

Further, by making the barrel length of the work roll longer than the barrel length of the intermediate roll, preferably 1.4 to 2.5 times as large as that of the backup roll, the work roll can be extended over its entire length regardless of the shift amount of the intermediate roll. Since it always and reliably contacts the intermediate roll, the vertical rigidity of the rolling mill can be further enhanced, and in particular, the reduction of meandering can be promoted. Moreover, since the contact area between the rolls is wide and the increase in the linear pressure between the rolls can be suppressed, it is also effective in extending the life of the rolls.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated examples. [Embodiment 1] FIG. 1 shows a six-high rolling mill according to the present invention. Here, a work roll 2, an intermediate roll 3 and a backup roll 4 which are respectively paired up and down, are arranged in the housing 1, and both work rolls 2 are arranged.
By means of their respective shift devices 5 allowing mutually opposite shifts in their respective axial directions, while the two intermediate rolls 3 are in each case also driven by their respective other shift device 6 in opposite directions in their respective axial directions. It becomes possible to shift the direction.

The backup roll 4 comprises a so-called flat roll whose barrel diameter is uniform over the entire length,
The intermediate roll 3 has a barrel length longer than that of the backup roll 4, and as shown in FIG.
It is provided with a character-shaped roll crown.

As the S-shaped roll crown forming curve, as described above, one pitch is extracted from a higher-order function curve of third or higher order and one pitch is extracted from a sine function curve. It is possible to select either the ones or curves that approximate those curves. The S-shaped roll crown provided to the intermediate roll preferably has a maximum and minimum diameter difference of 1 mm or less.

As shown in FIG. 1, the respective intermediate rolls 3 having such roll crowns are arranged in the directions opposite to each other, and based on the action of the shift device 6, the intermediate rolls 3 shown in FIG.
The positions are shifted in the opposite directions between the minimum shift position and the maximum shift position shown in (a) and (b), respectively.
At the minimum shift position shown in FIG. 3 (a), one barrel end 3a of the intermediate roll 3 is exactly aligned with one barrel end 4a of the backup roll 4, while FIG.
At the maximum shift position shown in (b), the other barrel end 3b of the intermediate roll 3 is exactly aligned with the other barrel end 4b of the backup roll 4.

Further, the work roll 2 has a backup roll 4 as shown in FIGS. 1 and 3.
It is a flat roll with a uniform diameter and a barrel length that is about the same as the above.

When the respective rolls 2, 3 and 4 are constructed as described above, in FIG. 1, each work roll 2 is attached to a motor 9 through a spindle 7 and a pinion stand 8 in sequence and a speed reducer. Connect to 10. Here, by the shift device 5 connected to the work roll 2 via the pinion stand 8 and the spindle 7,
The shift position of the work roll 2 is determined by, for example, a position detecting device 11 using a magnescale, and the shift position of the intermediate roll 3 by a shift device 6 connected to the intermediate roll 3 is also different from that by using, for example, a magnescale. The position detection device 12 detects each. In the figure, 13 is a rolled plate to be a product, 14 is a work roll bender, and 15 is a work roll bender.
Indicates an intermediate roll bender and 16 indicates a load cell, respectively.

FIG. 4 is a control system diagram of the rolling mill as described above. That is, reference numeral 21 in the drawing denotes an arithmetic unit. The arithmetic unit 21 has rolling conditions for one cycle, for example, the shape and size of the tapered portion of the work roll 2, the crown shape and size of the intermediate roll 3, the plate width, and the reduction of each stand. The rate, the finished plate thickness, the target plate crown, the target plate shape, and the like are input in advance, and the arithmetic unit 21 calculates the target plate crown and the target plate crown based on these information and the cyclic shift amount of the work roll 2. The shift amount of the intermediate roll 3 and the set values of the bending forces of the roll benders 14 and 15 are calculated in order to obtain the plate shape.

Based on the calculation result, the shift control device 22 and the bender control device 23 respectively control the operations of the shift device 6 and the roll benders 14 and 15 to control the shift amount of the intermediate roll 3 and the roll bending force. Each is set as a set value, and the start of rolling is awaited in such a state.

Next, during rolling, the plate shape detector 2
4 and the plate crown detector 25, based on a feedback signal to the arithmetic unit 21, the arithmetic unit 21 shifts the intermediate roll 3 and the respective rolls in order to realize the target plate shape and the target plate crown with high accuracy. Then, the shift control device 22 and the bender control device 23 adjust the shift amount of the intermediate roll 3 and the bending forces of the roll benders 14 and 15 based on the correction values.

When rolling with such a rolling mill,
In particular, under the action of the roll crown of the intermediate roll 3, the rolling load applied to the side end portion of the sheet bar from the work roll can be extremely effectively reduced.
Together with the actions of 4 and 15, the plate crown can be controlled with high accuracy, and its control range can be made sufficiently wide by shifting the intermediate roll 3.

By the way, the procedure for applying the roll crown to the intermediate roll 3 will be described by taking the application of the roll crown according to the cubic equation shown in FIG. 2 as an example. That is, FIG.
The lower roll profile of the intermediate roll 3 shown in (a) follows the curve shown in (b) of the figure, and this curve is expressed by the following equation.
It can be represented by (1).

[Equation 1] Here, y: roll crown generatrix curve, a: cubic coefficient,
b: linear coefficient, x: barrel center coordinates, L: half of intermediate roll barrel length, δ: intermediate roll shift amount (however, x = L
(Starting from _B ), OF: Axial offset amount.

On the other hand, since the upper roll profile of the intermediate roll 3 is point-symmetrical with the lower roll, the following equation (2) is obtained.

[Equation 2]

From the above equations (1) and (2), the gap difference Δy between the upper and lower intermediate rolls is

[Equation 3]

The synthetic roll crown CR formed by the upper and lower intermediate rolls has the following formula with the mill center at zero (0).
It can be represented by (4).

[Equation 4]

The shift amount δ _max that gives the maximum composite roll crown is

[Equation 5] Here, L _B : 1/2 of the backup roll barrel length, and the offset amount OF is set in order to make the combined crown of the upper and lower intermediate rolls zero by the minimum shift amount δ _min {= − (L−L _B )}. To

[Equation 6] And need to.

In the case of normal hot rolling, the minimum crown amount may be set when the combined crown of the upper and lower intermediate rolls is zero, but when the minimum combined crown needs to be larger or smaller than zero. , The offset amount OF when the shift amount of the intermediate roll is zero (x = L) as a starting point
To

[Equation 7] Here, C may be a constant.

Further, in order to reduce the maximum and minimum diameter difference of the intermediate roll without changing the synthetic roll crown, the following formula obtained by substituting the formulas (5) and (6) into the above formula (4) is given.

[Equation 8] From minimizing third order coefficients a, thus _{(L-L B) / L} 3
It is effective to maximize. And (L-L _B) / L
To maximize ³ ,

[0036]

[Equation 9] And need to. Therefore, by making the barrel length of the intermediate roll 1.5 times the barrel length of the backup roll, the difference between the maximum and minimum diameters of the intermediate roll can be made small, that is, the grinding amount when forming the S-shaped roll crown on the intermediate roll can be reduced. Therefore, the roll grinding that contributes to the longer life of the intermediate roll is realized.

[0037] Here, the inter-roll line pressure distribution and plate crown in the case of using the intermediate rolls having a barrel length according to L = 1.5 L _B, as compared with the case of using the intermediate roll of L = 1.1 L _B, As shown in FIG. As shown in the figure, since barrel length 1.5 L _B (solid line) in the work roll bends along the intermediate rolls, compared barrel length 1.1 L _B (the dashed line), the plate crown is smaller .. The maximum line pressure as shown in Table 1, the maximum line pressure in the case of the barrel length is 1.5 L _B is clear that smaller, it can be seen that may contribute to improving the roll life.

[0038]

[Table 1]

(Experimental Example) Next, the experimental result regarding the barrel length of the intermediate roll will be described. That is, work roll barrel length: 2300 mm and diameter: 680 mm, backup roll barrel length: 2300 mm, and diameter: 1330
mm, the barrel length of the intermediate roll having a cubic coefficient a of 0.833 in the above formula (8) of 0.833 is variously changed, and the strip width is respectively:
Rolling was carried out at a thickness of 1500 mm from the stand-entry side: 5.2 mm to a thickness of 4.16 mm, and various investigations were conducted.

Firstly in FIG. 6, to show the relationship between the ratio of the barrel length of the intermediate rolls and backup rolls and (L / L _B) and the maximum line pressure between the intermediate rolls and backup rolls, the ratio (L / L _B) Since the linear pressure gradually decreases when the ratio is 1.2 times or more, it can be seen that it is advantageous to make the barrel length of the intermediate roll longer than that of the backup roll, preferably 1.2 times or more.

Further, FIG. 7 shows the contact state of the intermediate roll and the backup roll with respect to the barrel length ratio under the condition that the same plate crown is obtained. From the figure, it can be seen that if the ratio is set to 1.2 times or more, the occurrence of the non-contact area can be prevented, and it is effective for improving the plate thickness accuracy, meandering, and suppressing the diaphragm.

By the way, if there is a gap between the shift block of the intermediate roll attached to the housing of the rolling mill and the chock of the intermediate roll (generated due to abrasion due to sliding of the intermediate roll or poor mechanical accuracy), FIG. As shown in (a), the intermediate roll 2 is bent. Therefore, as shown in FIG. 6B, the maximum displacement amount t between the chocks is defined as the horizontal deflection amount, and when the gap is 3 mm, the ratio of the horizontal deflection amount t to the barrel lengths of the intermediate roll and the backup roll ( L / L
_The result of having investigated the relationship with _B ) is shown in FIG.

As shown in FIG. 9, the horizontal deflection amount t increases as the barrel length ratio increases. When the amount of horizontal deflection increases, the gap between the upper and lower work rolls changes, and when the amount of horizontal deflection differs between the upper and lower intermediate rolls, the axial gap between the upper and lower work rolls changes.
This causes disadvantages such as the plate crown and plate shape changing during rolling. Therefore, it is preferable that the intermediate roll length is short in order to reduce the barrel length ratio, but the horizontal deflection amount up to about 0.45 mm has little influence on the plate crown and the plate shape, so it does not cause a problem in normal rolling, and Since it is customary to control the gap to 3 mm or less, it can be seen that rolling is possible if the barrel length of the intermediate roll is 2.5 times or less the barrel length of the backup roll.

(Specific Example) Next, a comparative test regarding the plate crown distribution with respect to the number of rollings when the rolling mill according to the present invention is used and when the conventional rolling mill is used will be described. Inventive rolling mill In a hot finish rolling mill train in which a 6-high rolling mill configured as shown in FIG. 1 is arranged in 3 rear stages, a sheet bar having a width of 900 to 1600 mm and a thickness of 40 mm and a finishing thickness of 1.6 to 3.2 are used.
It was rolled into a thin low carbon steel sheet having a thickness of mm. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. In addition, here, the barrel length of the work roll
2300mm, the intermediate roll barrel length is 3000mm, the backup roll barrel length is 2300mm,
The diameter difference between the maximum diameter and the minimum diameter of the intermediate roll was 0.8 mm, and the intermediate roll was shifted in the range of 0 mm to 700 mm.

A three-stage rolling mill including a final roll of a conventional rolling mill was provided with a six-high rolling mill each including a work roll having a flat length of 2300 mm, an intermediate roll and a backup roll. Meanwhile, while shifting the intermediate roll, the same hot rolling as in the case of the invention rolling mill was performed, and the sheet crown was measured in the same manner as in that case.

Test Results The results of these measurements are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it. The rolling schedule regarding the strip width was the same for both the invention rolling mill and the conventional rolling mill.

Table 2 shows the number of times of drawing, the plate thickness accuracy, and the plate crown average value when 100,000 tons of rolling was performed in a thin product cycle using the above-mentioned invention rolling mill and conventional rolling mill.
According to this table, in the invention rolling mill,
Both the strip thickness accuracy and stripability (reduction in drawing) are far superior to those of conventional rolling mills.

[0048]

[Table 2]

In carrying out rolling by the above rolling mill, it is preferable to supply lubricating oil between the backup roll and the intermediate roll and / or between the intermediate roll and the work roll. That is, as shown in FIG. 11, a lubricating nozzle 26 for supplying lubricating oil is arranged between the backup roll 4 and the intermediate roll 3 and between the intermediate roll 3 and the work roll 2, and the lubricating oil tank The lubricating oil is pumped up from 27 by a pump 28, and this lubricating oil is guided to a lubricating nozzle 26 via a supply pipe 29. Further, to the intermediate roll 3 and the work roll 2, the cooling water led from the cooling water pump 30 through the supply pipe 31 is supplied from the cooling nozzle 32. In addition,
As the lubricating oil used here, a high-concentration emulsion containing an extreme pressure agent in the base oil is preferable, and a low-concentration emulsion may be used especially when the lubricating oil also serves for roll cooling.

Further, as shown in FIG. 12, in the vicinity of the large diameter portion of the intermediate roll 3, in order to make the lubricating oil supply amount larger than in the vicinity of the small diameter portion, the installation intervals of the lubricating nozzles 26 are set. It is preferable to make it narrow. Even if the concentration of the lubricating oil is changed in the roll axis direction without increasing the supply amount of the lubricating oil, the same effect can be expected.

By the way, in the above rolling by the rolling mill shown in FIG. 1, 10% emulsion was used as the lubricating oil and industrial water was used as the cooling water.
When rolling was performed according to the above, rolling exceeding 120 rolls could be achieved without causing seizure of the rolls. As a comparison, when the same rolling was performed only by cooling with industrial water, seizure occurred on the work roll and the intermediate roll when the number of rolls exceeded 100, and the surface quality of the plate deteriorated.
When the number of rolls exceeded 120, a large seizure occurred, making it difficult to continue rolling.

In the above-described rolling mill in which the roll roll is provided on the intermediate roll, the linear pressure distribution between the rolls changes depending on the size of the roll crown, and as a result, the deflection of the shaft center of the work roll changes. It is possible to control the plate crown and thus the shape. Therefore, the crown control amount does not change depending on the magnitude of the rolling load. Therefore, when the diameter of the work roll is small, the amount of deflection of the shaft center changes greatly, and the amount of crown control due to the shift of the intermediate roll also increases. On the other hand, when the diameter of the work roll is large, the change in the amount of deflection of the shaft center is small, and the crown control amount due to the shift of the intermediate roll is also small.

Regarding the diameter of this work roll and the controllable amount of crown, the results obtained by examining a rolled plate with a width of 1500 mm are shown in FIG.
Shown in 13. From the figure, it can be seen that the crown control amount increases when the diameter of the work roll is made small, preferably 700 mm or less. On the other hand, the diameter of the work roll is 400 mm
If it is less than 100 mm, the horizontal deflection of the work roll becomes large, the plate shape deteriorates, and it becomes difficult to drive the work roll, and the bending effect by the work roll becomes small.Therefore, it is necessary to secure a diameter of 400 mm or more. desirable.

[Embodiment 2] In FIG. 14, the vertical length of the rolling mill is improved by making the barrel length of the work roll 2 longer than the barrel length of the intermediate roll 3 in the 6-high rolling mill shown in FIG. The following is a rolling mill. That is, the vertical rigidity of the rolling mill is determined by the gap amount between the work rolls when the rolling load changes. Deflection of the backup roll, elastic deformation of the housing, and flat deformation between the rolls affect the gap amount. Then, when the barrel length of the work roll is long, the contact area between the work roll and the intermediate roll also becomes long, and even if the rolling load changes, the linear pressure between the rolls is smaller than that when the contact area is short, Since the size becomes smaller, the vertical rigidity of the rolling mill naturally increases. Therefore, even when the rolling plate passes off the center of the rolling mill, if the barrel length of the work roll is long, the linear pressure change between the rolls is small and the difference in the amount of deformation between the left and right sides of the rolling mill center is also small. It is effective in suppressing the meandering and diaphragm of the plate. In addition, the preferable range of the barrel length of the work roll is
As already mentioned, the backup roll barrel length is 1.
It is 4 to 2.5 times, but the reason for limiting the upper and lower limits is
This is almost the same as the case of the intermediate roll described above.

With respect to this rolling mill as well, a comparison was made between the case of using this rolling mill and the case of using the conventional rolling mill with respect to the plate crown distribution with respect to the number of rollings. Inventive Rolling Mill A 6-high rolling mill having the structure shown in FIG. 14 was placed on the third stand in the rear stage of the hot finish rolling mill, and rolling was performed under the same conditions as the treatment in Example 1 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the work roll barrel length is 3400 mm, the intermediate roll barrel length is 3000 mm, and the backup roll barrel length is 2300.
mm, the difference between the maximum diameter and the minimum diameter of the intermediate roll is 0.8 mm, and the intermediate roll is 0 mm.
To 700 mm. The specifications of the conventional rolling mill for comparison are the same as those in the first embodiment.

Test Results The measurement results of the plate crown are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Table 3 shows the number of times of drawing, the plate thickness accuracy, and the plate crown average value when 100,000 tons of rolling was performed in a thin product cycle using the above-mentioned invention rolling mill and conventional rolling mill.
According to this table, in the invention rolling mill,
Both the strip thickness accuracy and stripability (reduction in drawing) are far superior to those of conventional rolling mills.

[0058]

[Table 3]

[Embodiment 3] The 6-high rolling mill shown in FIG.
It was placed on the first stage stand of the cold rolling mill train consisting of four stands, and the coil having a width of 900 to 1100 mm and a thickness of 2 to 3 mm was rolled into a thin low carbon steel sheet with a finished thickness of 0.5 mm. .. 10 from the edge of the plate after this treatment
The plate thickness deviation at the 0 mm position was investigated. In addition, here, the barrel length of the work roll is 2000 mm, the barrel length of the intermediate roll is
When the barrel length of the backup roll is 2700 mm and 2000 mm, the diameter difference between the maximum diameter and the minimum diameter of the intermediate roll is 0.8 mm, and the intermediate roll is 0 mm to 70 mm.
It was shifted in the range of 0 mm.

In a conventional rolling mill, the first stand is provided with a six-high rolling mill, which is composed of flat rolls and has a work roll having a barrel length of 2000 mm, an intermediate roll and a backup roll. While shifting the roll,
The same cold rolling as in the case of the invention rolling mill was performed, and the sheet thickness deviation was measured in the same manner as in the case.

Test Results FIG. 16 shows the measurement results of the plate thickness deviation. According to the figure, when the rolling mill of the present invention is used, it is clear that the occurrence of edge drops is reduced.

Further, when the invention rolling mill and the conventional rolling mill described above are used to further roll 100,000 tons, the number of times of drawing and the edge drop amount are as shown in Table 4, and according to this table, In the invention rolling mill, both the plate thickness accuracy and the sheet passing property (reduction of drawing) are far superior to those of the conventional rolling mill. However, the edge drop amount was defined by the plate thickness deviation at positions of 100 mm and 7.5 mm from the edge.

[0063]

[Table 4]

Here, when the rolling mill of the present invention is applied to cold rolling, particularly in the case of performing edge drop control, the deformation in the sheet width direction is caused as the rolled sheet moves to the stand after the cold rolling. Since it becomes smaller, it is indispensable to arrange it on the first stand, and it is preferable to sequentially expand the applicable range to the subsequent stage. Further, tension acts between the stands of the cold rolling mill to limit the meandering of the plate, but if the hot rolled plate has a large camber or wedge, narrowing due to these may occur. However, in this rolling mill, since the barrel length of the intermediate roll is lengthened to secure the vertical rigidity, it is possible to avoid the occurrence of drawing.

Next, a six-high rolling mill will be described in which the roll crown applied to the intermediate roll has a tapered shape or a tapered shape. [Embodiment 4] The rolling mill shown in FIG. 17 is an example in which the intermediate roll 3 is provided with a roll crown having a tapered shape whose diameter gradually decreases toward one end of the barrel, and other configurations are shown in FIG. It is similar to a rolling mill. That is, each intermediate roll 3
Has a tapered portion 3a on the barrel end portions on the opposite sides to each other, and is continuous adjacent to the tapered portion 3a,
A roll having a uniform diameter portion 3b occupying most of the roll length is used.

Each of the intermediate rolls 3 has such a length as to be able to contact the backup roll 4 over its entire length in its maximum shift posture, and the tapered portion 3a of the intermediate roll 3 is also present. Has a region extending beyond the barrel end of the backup roll 4 to the roll end side under the condition that the shift amount thereof is zero.

Here, the tapered portion 3a contacts at least the backup roll 4, usually the work roll 2 and the backup roll 4 even when the work roll 2 is shifted, when the rolling load is applied. , To effectively reduce the contact line pressure between those rolls. Therefore, by appropriately selecting the contact position of the tapered portion 3a with the work roll 2 and the backup roll 4 by shifting the intermediate roll 3, the plate crown can be controlled as required.

By the way, the contour shape of the tapered portion 3a in the cross section including the axis is not limited to the taper shape as shown in FIG. 17 and the figure depending on the required plate crown, the maximum shift amount of the intermediate roll, and the like. The shape may be a sine or cosine curve shape shown in 18 (a), or a higher-order function curve shape of quadratic, quartic or quintic as shown in FIG.

In such a rolling mill, the intermediate roll 3
For example, as shown in FIG. 19, when the points are shifted symmetrically, the contact linear pressure of the barrel portions of the rolls 2 and 4 which come into contact with the tapered portion 3a of the intermediate roll 3 is extremely effectively reduced. This, in combination with the action of the roll benders 14 and 15, allows the plate crown to be controlled over a wide range as required.

FIG. 20 is a graph showing the linear pressure distribution between the work roll 2 and the intermediate roll 3 on the upper side. In the line contact state of these two rolls 2 and 3, the intermediate roll 3
Pressure acting on the work roll 2 from the work roll 2
In the contact portion with the tapered portion 3a, the diameter of the tapered portion 3a decreases as the diameter thereof decreases, corresponding to the tapered shape of the tapered portion 3a, and becomes the smallest value at the barrel end of the work roll 2. Therefore, the work roll 2 is
As a whole, it is curved in a downwardly convex shape, and the plate crown of the plate 13 is effectively reduced as compared with the case where the intermediate roll 3 is not shifted.

Thus, according to this rolling mill, in particular, the intermediate roll 3 has a longer length than the backup roll 4, and even if the intermediate roll 3 shifts, the intermediate roll 3 and the hack-up roll are 4 and the work roll 2 do not change the contact length, and the vertical rigidity of the rolling mill does not change, so that the plate thickness accuracy of hot finish rolling is greatly improved. On the other hand, even when off-centered, the change in the linear pressure on the left and right sides of the rolling mill becomes smaller than in the prior art, the change in the flatness between the rolls, and thus the plate wedge becomes smaller,
The bending of the plate can be effectively reduced.

(Concrete Example) Hereinafter, a comparative test regarding the plate crown distribution and the like with respect to the number of rollings when the rolling mill according to the present invention is used and when the conventional rolling mill is used will be described. Inventive Rolling Mill In a hot rolling mill train in which the 6-high rolling mill having the configuration shown in FIG. 17 is arranged in the rear 3 stands, a sheet bar with a width of 900 to 1600 mm and a thickness of 40 mm and a finishing thickness of 1.6 to 3.2 mm are used. The thin low carbon steel sheet was subjected to rolling treatment. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, when the barrel length of each of the work roll and the backup roll is set to 2300 mm and the barrel length of the intermediate roll is set to 3000 mm, the tapered portion of the intermediate roll is 1.6 × 10 ^-3 (0.32 mm / 200 mm per diameter).
Taper shape and the intermediate roll from 0 mm
Shifted in the 700 mm range.

A conventional three-stage rolling mill including the final stand of the rolling mill was provided with a six-high rolling mill, each of which was composed of a flat roll and had a barrel length of 2300 mm, a work roll, an intermediate roll and a backup roll. In the meantime, while shifting the intermediate roll, the same rolling as in the case of the invention rolling mill was performed, and the same sheet crown measurement as in that case was performed.

Test Results These measurement results are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it. The rolling schedule regarding the strip width was the same for both the invention rolling mill and the conventional rolling mill.

Table 5 shows the number of times of drawing, plate thickness accuracy and plate crown average value when the invention rolling mill and the conventional rolling mill described above were used to further roll 100,000 tons. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0076]

[Table 5]

[Embodiment 5] FIG. 22 shows a rolling mill in which the barrel length of the work roll 2 in the 6-high rolling mill shown in FIG. 17 is longer than the barrel length of the intermediate roll 3. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A 6-high rolling mill having the configuration shown in FIG. 22 was placed on the third stand in the rear stage of the hot finish rolling mill, and rolling was performed under the same conditions as the treatment in Example 4 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the work roll barrel length is 3400 mm, the intermediate roll barrel length is 3000 mm, and the backup roll barrel length is 2300.
In the place of mm, the same taper as in Example 4 was applied to the intermediate roll, and the intermediate roll was shifted in the range of 0 mm to 700 mm. For the specifications of the conventional rolling mill for comparison, see Example 4
It is similar to the case of.

Test Results The measurement results of the plate crown are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Further, when the invention rolling mill and the conventional rolling mill described above are used to further roll 100,000 tons, the number of times of drawing, the plate thickness accuracy and the plate crown average value are as shown in Table 6. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0080]

[Table 6]

[Embodiment 6] The rolling mill shown in FIG. 24 is an example in which the intermediate roll 3 is provided with a roll crown having a taper shape whose diameter gradually decreases from the barrel center to both barrel ends, respectively. It is similar to the rolling mill shown in FIG. 1 above. That is, each of the intermediate rolls 3 has a tapered portion 3a which is tapered at the barrel end portion on the opposite side to each other, is continuous adjacent to this portion 3a, and is tapered at a gentle inclination to the other end of the roll. It is configured by a roll having a portion 3b, that is, a roll crown having a middle-high asymmetry. Each of such intermediate rolls 3 has a length capable of contacting the backup roll 4 over its entire length even in the maximum shift posture.

Here, the tapered portion 3a contacts at least the backup roll 4, usually the work roll 2 and the backup roll 4 even when the work roll 2 is shifted, when the rolling load is applied. , To effectively reduce the contact line pressure between those rolls. Therefore, by appropriately selecting the position of the boundary portion between the tapered portions 3a and 3b by shifting the intermediate roll 3, the plate crown can be controlled as required.

By the way, the contour shape of the intermediate roll in the cross section including the axis is not limited to the double taper shape as shown in FIG. 24, depending on the required plate crown, the maximum shift amount of the intermediate roll, and the like. The shape may be a sine or cosine curve shape shown in FIG. 25 (a), or a higher-order function curve shape of quadratic, quartic or quintic or higher as shown in FIG. The contour shapes of the tapered portions may be the same or different.

In this rolling mill, when the intermediate roll 3 is shifted in point symmetry, as shown in FIG. 26, for example, each of the rolls 2, which come into contact with the tapered portions 3a and 3b of the intermediate roll 3, The contact line pressure of the barrel portion of 4 can be reduced very effectively, which is why
Together with the action of the roll benders 14 and 15, the plate crown can be controlled over a wide range as required.

In particular, when the double-tapered roll crown is applied to the intermediate roll 3, the barrel end 4a of the backup roll 4 and the barrel end 3 of the intermediate roll 3 shown in FIG.
In the maximum shift posture in which c matches, the position of the boundary portion between the tapered portions 3a and 3b can be matched with the axial barrel center of the backup roll 4, and the rigidity in the roll axial direction of the rolling mill can be made uniform. ..

The linear pressure distribution between the upper work roll 2 and the intermediate roll 3 in this rolling mill is the same as that shown in FIG. 20, that is, the pressure applied from the intermediate roll 3 to the work roll 2 is In the contact portion of the work roll 2 with the tapered portion, the diameter of the work roll 2 decreases as the diameter thereof decreases in correspondence with the tapered shape of the tapered portion, and becomes the smallest value at the barrel end of the work roll 2. Therefore, the work roll 2 as a whole is curved in a downwardly convex shape, and the plate crown of the plate 13 is effectively reduced as compared with the case where the intermediate roll 3 is not shifted. ..

(Specific Example) Hereinafter, a comparative test regarding the plate crown distribution with respect to the number of rollings and the like between the case of using the rolling mill of the present invention and the case of using the conventional rolling mill will be described. Inventive Rolling Mill In a rolling mill row in which the 6-high rolling mill having the configuration shown in FIG. 24 is arranged in 3 rear stands, the width is 900 to 1600 mm and the thickness is 40 mm.
A sheet bar of mm was rolled into a thin low carbon steel sheet having a finish thickness of 1.6 to 3.2 mm. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment.
In addition, here, when the barrel length of each of the work roll and the hack-up roll is set to 2300 mm and the barrel length of the intermediate roll is set to 3000 mm, the tapered portion 3a of the intermediate roll is set to 1.6 × 10 ^-3 (0.32 mm / 200 mm diameter). Hit)
The taper shape and the tapered portion 3b of 0.1 × 10 ^-3 (0.02m
The diameter was m / 200mm (per diameter) and the intermediate roll was shifted in the range of 0mm to 700mm.

A 6-high rolling mill , which is composed of flat rolls and has a work roll having a barrel length of 2300 mm, an intermediate roll and a backup roll, is provided in each of the latter three stands including the final stand of the conventional rolling mill . In the meantime, while shifting the intermediate roll, the same rolling as in the case of the invention rolling mill was performed, and the same sheet crown measurement as in that case was performed.

Test Results These measurement results are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it. The rolling schedule regarding the strip width was the same for both the invention rolling mill and the conventional rolling mill.

Table 7 shows the number of times of drawing, plate thickness accuracy and plate crown average value when the invention rolling mill and the conventional rolling mill described above were used to further roll 100,000 tons. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0091]

[Table 7]

[Embodiment 7] FIG. 28 shows a rolling mill in which the barrel length of the work roll 2 in the 6-high rolling mill shown in FIG. 24 is longer than the barrel length of the intermediate roll 3. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A 6-high rolling mill having the configuration shown in FIG. 28 was placed in the third stand of the hot-finish rolling mill row, and rolling was performed under the same conditions as in the treatment in Example 1 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the work roll barrel length is 3400 mm, the intermediate roll barrel length is 3000 mm mm, and the backup roll barrel length is 23 mm.
When the distance was set to 00 mm, the same taper as in Example 6 was applied to the intermediate roll, and the intermediate roll was shifted in the range of 0 mm to 700 mm.
The specifications of the conventional rolling mill for comparison are the same as in the case of Example 6.

Test Results FIG. 29 shows the measurement results of the plate crown. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Further, when the invention rolling mill and the conventional rolling mill described above are used to further roll 100,000 tons, the number of times of drawing, the plate thickness accuracy and the plate crown average value are as shown in Table 8. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0095]

[Table 8]

The various rolling mills in which the S-shaped, one-tapered or both-tapered roll crowns are provided to the intermediate roll have been described above, but various combinations of roll crowns are possible. The combination is illustrated in.

[Embodiment 8] A six-high rolling mill shown in FIG. 30 applies an S-shaped roll crown to the intermediate roll 3 while
In this example, the work roll 2 is provided with a tapered roll crown. In this rolling mill, the work roll 2 is
By shifting from the arrangement shown in FIG. 31 (a) as shown in FIG. 31 (b), the tapered portion 2a of the work roll 2 is moved.
However, since the roll gap between the upper and lower work rolls 2 is directly expanded at the side end of the rolled material 13, the edge drop can be further reduced. Further, as shown in FIG. 32, by shifting the work roll 2, the distance EL (see FIG. 31) from the starting point of the tapered portion 2a to the plate edge can be adjusted to change the edge drop. When the edge drop amount is given, the edge drop control can be performed by the work roll shift.

Regarding this rolling mill as well, a comparison was made between the case where this rolling mill was used and the case where a conventional rolling mill was used, regarding the distribution of sheet crown with respect to the number of rolling mills. Inventive Rolling Mill In a rolling mill row in which the 6-high rolling mill having the configuration shown in FIG. 30 is arranged in the rear 3 stands, the width is 900 to 1600 mm and the thickness is 40.
A sheet bar of mm was rolled into a thin low carbon steel sheet having a finish thickness of 1.6 to 3.2 mm. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment.
In this example, the work roll and backup roll each have a barrel length of 2300 mm and the intermediate roll has a barrel length of 3000 mm, and the S-shaped roll crown has a maximum and minimum diameter difference of 0.8 mm in the intermediate roll. In addition, the taper portion 2a of the work roll was tapered to 0.8 × 10 ⁻³ (per 0.16 mm / 200 mm diameter), and the intermediate roll was shifted in the range of 0 mm to 700 mm.

A 6-high rolling mill , which is composed of both flat rolls and has a work roll having a barrel length of 2300 mm, an intermediate roll, and a backup roll, is provided in each of the latter three stands including the final stand of the conventional rolling mill . In the meantime, while shifting the intermediate roll, the same rolling as in the case of the invention rolling mill was performed, and the same sheet crown measurement as in that case was performed.

Test Results These measurement results are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it. The rolling schedule regarding the strip width was the same for both the invention rolling mill and the conventional rolling mill.

Table 10 shows the number of times of drawing, the amount of edge drop, the plate thickness accuracy, and the plate crown average value when 100,000 tons of rolling was performed using the above-mentioned invention rolling mill and conventional rolling mill. According to this table, the invention rolling mill is far superior to the conventional rolling mill in terms of strip thickness accuracy and stripability (reduction of drawing). However, the edge drop amount was the difference in plate thickness between the edge of 100 mm and 25 mm.

[0102]

[Table 9]

[Embodiment 9] The six-high rolling mill shown in FIG.
It was placed on the first stage stand of the cold rolling mill train consisting of four stands, and the coil having a width of 900 to 1100 mm and a thickness of 2 to 3 mm was rolled into a thin low carbon steel sheet with a finished thickness of 0.5 mm. .. 10 from the edge of the plate after this treatment
The plate thickness deviation at the 0 mm position was investigated. In addition, here, the barrel length of the work roll is 2000 mm, the barrel length of the intermediate roll is
When the barrel length of the backup roll is 2700 mm and 2000 mm, the diameter difference between the maximum diameter and the minimum diameter of the intermediate roll is 0.8 mm, and the intermediate roll is 0 mm to 70 mm.
It was shifted in the range of 0 mm.

In the conventional rolling mill, the first stand is provided with a six-high rolling mill, which is composed of flat rolls and has a work roll having a barrel length of 2000 mm, an intermediate roll and a backup roll. While shifting the roll,
The same cold rolling as in the case of the invention rolling mill was performed, and the sheet thickness deviation was measured in the same manner as in the case.

Test Results FIG. 34 shows the measurement results of the plate thickness deviation. As shown in the figure, it is clear that the occurrence of edge drops is significantly reduced when the rolling mill of the present invention is used.

Further, when the invention rolling mill and the conventional rolling mill described above are used to further roll 100,000 tons, the edge drop amount and the number of times of drawing are as shown in Table 10. According to this table, In the invention rolling mill, both the plate thickness accuracy and the sheet passing property (reduction of drawing) are far superior to those of the conventional rolling mill.

[0107]

[Table 10]

[Embodiment 10] FIG. 35 shows a rolling mill of the 6-high rolling mill shown in FIG. 30, in which the work rolls 2 are provided with roll-tapered roll crowns. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A 6-high rolling mill having the structure shown in FIG. 35 was placed on the third stand in the rear stage of the hot finish rolling mill, and rolling was performed under the same conditions as the treatment in Example 8 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the two tapered portions 2a and 2b of the work roll are set to 0.
The taper was 4 × 10 ⁻³ (per 0.08 mm / 200 mm diameter) and the intermediate roll was shifted in the range of 0 mm to 700 mm. The specifications of the conventional rolling mill for comparison are the same as in the case of Example 8.

Test Results The measurement results of the plate crown are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Table 11 shows the number of times of drawing, plate thickness accuracy and plate crown average value when 100,000 tons of rolling was performed using the above invention rolling mill and conventional rolling mill. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0111]

[Table 11]

[Embodiment 11] FIG. 37 shows a rolling mill in which the barrel length of the work roll 2 in the 6-high rolling mill shown in FIG. 35 is longer than the barrel length of the intermediate roll 3. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A six-high rolling mill configured as shown in FIG. 37 was placed in the third stand of the hot finishing rolling mill, and rolling was performed under the same conditions as the treatment in Example 10 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the work roll barrel length is 3400 mm, the intermediate roll barrel length is 3000 mm, and the backup roll barrel length is 2300.
mm, the size and shape of the intermediate roll were the same as in Example 10, and the intermediate roll was 0 mm to 700 mm.
Shifted in mm range. The specifications of the conventional rolling mill for comparison are the same as in the case of Example 10.

Test Results The results of plate crown measurements are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Table 12 shows the number of times of drawing, plate thickness accuracy and plate crown average value when the invention rolling mill and the conventional rolling mill described above were used to further roll 100,000 tons. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0115]

[Table 12]

[Embodiment 12] FIG. 39 shows a rolling mill of the 6-high rolling mill shown in FIG. 37 in which the work rolls 2 are provided with roll-tapered roll crowns. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A 6-high rolling mill having the configuration shown in FIG. 39 was placed in the third stand of the hot finishing rolling mill, and rolling was performed under the same conditions as the treatment in Example 11 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the roll size and shape were the same as in Example 11, and the taper portion 2a of the work roll 2 was 0.8 × 10 ⁻³ (0.16 mm).
/ 200mm per diameter) and 2b of 0.01 × 10 ^-3 (0.02 mm)
(/ 200 mm diameter) and the intermediate roll was shifted in the range of 0 mm to 700 mm. The specifications of the conventional rolling mill for comparison are the same as in the case of Example 11.

Test Results The measurement results of the plate crown are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Further, when the invention rolling mill and the conventional rolling mill described above are used to further roll 100,000 tons, the number of times of drawing, the plate thickness accuracy and the plate crown average value are as shown in Table 13. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0119]

[Table 13]

[Embodiment 13] The six-high rolling mill shown in FIG.
In this example, the intermediate roll 3 and the work roll 2 are provided with tapered roll crowns. This rolling mill also
When using this, and when using a conventional rolling mill,
A comparison was made regarding the plate crown distribution and the like with respect to the number of rollings. Inventive Rolling Mill In a rolling mill row in which the 6-high rolling mill having the configuration shown in FIG. 41 is arranged in the rear 3 stands, the width is 900 to 1600 mm and the thickness is 40.
A sheet bar of mm was rolled into a thin low carbon steel sheet having a finish thickness of 1.6 to 3.2 mm. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment.
Here, when the barrel length of each of the work roll and the backup roll is set to 2300 mm and the barrel length of the intermediate roll is set to 3000 mm, the tapered portion 3a of the intermediate roll is 1.6 × 10 ^-3 (per 0.32 mm / 200 mm diameter). Taper and work roll taper 2
a was 0.8 × 10 ⁻³ (per 0.16 mm / 200 mm diameter) taper, and the intermediate roll was shifted in the range of 0 mm to 700 mm.

[0121] A conventional three-stage rolling mill including the final stand of the rolling mill was provided with a six-high rolling mill, each of which was composed of a flat roll and had a work roll having a barrel length of 2300 mm, an intermediate roll and a backup roll. Meanwhile, while shifting the intermediate roll, the same rolling as in the case of the invention rolling mill was performed, and the same sheet crown measurement as in that case was performed.

Test Results These measurement results are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it. The rolling schedule regarding the strip width was the same for both the invention rolling mill and the conventional rolling mill.

When the invention rolling mill and the conventional rolling mill described above are used to further roll 100,000 tons, the number of times of drawing, the plate thickness accuracy and the plate crown average value are as shown in Table 14. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0124]

[Table 14]

[Embodiment 14] FIG. 43 shows a rolling mill of the 6-high rolling mill shown in FIG. 41, in which the work rolls 2 are provided with roll-tapered roll crowns. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A 6-high rolling mill having the configuration shown in FIG. 43 was placed in the third stand in the rear stage of the hot finish rolling mill, and rolling was performed under the same conditions as the treatment in Example 12 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the roll dimensions are the same as in Example 14 and the shape of the intermediate roll is the same as in Example 13, and the tapered portions 2a and 2b of the work roll 2 are 0.4 × 10 ⁻³ (per 0.8 mm / 200 mm diameter). Taper shape, and the intermediate roll from 0 mm
Shifted in the 700 mm range. The specifications of the conventional rolling mill for comparison are the same as in the case of Example 13.

Test Results The results of plate crown measurements are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Table 15 shows the number of times of drawing, plate thickness accuracy and plate crown average value when 100,000 tons of rolling was performed using the above-mentioned invention rolling mill and conventional rolling mill. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0128]

[Table 15]

[Embodiment 15] FIG. 45 shows a rolling mill in which the barrel length of the work roll 2 in the 6-high rolling mill shown in FIG. 41 is longer than the barrel length of the intermediate roll 3. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A 6-high rolling mill having the structure shown in FIG. 45 was placed on the third stand in the rear stage of the hot finish rolling mill, and rolling was performed under the same conditions as the treatment in Example 1 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the work roll barrel length is 3400 mm, the intermediate roll barrel length is 3000 mm, and the backup roll barrel length is 2300.
In the place of mm, the same taper as in Example 11 was applied to the intermediate roll and the work roll, and the intermediate roll was shifted in the range of 0 mm to 700 mm. The specifications of the conventional rolling mill for comparison are the same as in the case of Example 13.

Test Results The results of the plate crown measurement are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Further, when the invention rolling mill and the conventional rolling mill described above are used to further roll 100,000 tons, the number of times of drawing, the plate thickness accuracy and the plate crown average value are as shown in Table 16. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0132]

[Table 16]

[Embodiment 16] FIG. 47 shows a rolling mill of the 6-high rolling mill shown in FIG. 43 in which the work rolls 2 are provided with roll tapers having both tapered shapes. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A six-high rolling mill configured as shown in FIG. 47 was placed in the third stand of the hot finishing rolling mill in the latter stage, and rolling was performed under the same conditions as in the treatment in Example 13 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the size and shape of the roll are the same as in Example 15,
Set the taper portion 2a of the work roll to 0.8 × 10 ^-3 (0.16mm
/ 200mm (per diameter) and the other tapered portion 2b of the work roll 2 is 0.1 × 10 ^-3 (0.02 mm / 200mm)
Taper shape (per diameter) and 0 for the intermediate roll
Shifted from mm to 700 mm. The specifications of the conventional rolling mill for comparison are the same as in the case of Example 13.

Test Results The measurement results of the plate crown are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Table 17 shows the number of times of drawing, plate thickness accuracy and plate crown average value when the invention rolling mill and the conventional rolling mill described above were used to further roll 100,000 tons. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in terms of strip thickness accuracy and stripability (reduction of drawing).

[0136]

[Table 17]

Example 17! The six-high rolling mill shown in FIG.
In this example, the double roll taper roll crown is applied to the intermediate roll 3 while the single roll taper roll crown is applied to the work roll 2. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill In a rolling mill row in which the 6-high rolling mill having the configuration shown in FIG. 49 is arranged in 3 rear stands, the width is 900 to 1600 mm and the thickness is 40 mm.
A sheet bar of mm was rolled into a thin low carbon steel sheet having a finish thickness of 1.6 to 3.2 mm. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment.
In addition, here, when the barrel length of each of the work roll and the backup roll is set to 2300 mm and the barrel length of the intermediate roll is set to 3000 mm, the taper portion 3a of the intermediate roll is 1.6 × 10 ^-3 (0.32 mm / 200 mm per diameter). )
Taper shape and the other tapered portion 3b of 0.1 × 10 ^-3
(Per 0.02 mm / 200 mm diameter), and taper part 2a of the work roll is 0.8 × 10 ^-3 (0.16 mm / 20
0mm diameter) taper shape, intermediate roll from 0mm
Shifted in the 700 mm range.

A 6-high rolling mill , which is composed of flat rolls and has a work roll having a barrel length of 2300 mm, an intermediate roll, and a backup roll, is provided in each of the latter three stands including the final stand of the conventional rolling mill . In the meantime, while shifting the intermediate roll, the same rolling as in the case of the invention rolling mill was performed, and the same sheet crown measurement as in that case was performed.

Test Results These measurement results are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it. The rolling schedule regarding the strip width was the same for both the invention rolling mill and the conventional rolling mill.

Table 18 shows the number of times of drawing, plate thickness accuracy and plate crown average value when 100,000 tons of rolling was performed using the above-mentioned invention rolling mill and conventional rolling mill. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0141]

[Table 18]

[Embodiment 18] FIG. 51 shows a rolling mill of the 6-high rolling mill shown in FIG. 49, in which the work rolls 2 are provided with roll-tapered roll crowns. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A 6-high rolling mill having the configuration shown in FIG. 51 was placed in the third stand of the rear stage of the hot finish rolling mill, and rolling was performed under the same conditions as the treatment in Example 17 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the tapered portions 3a and 3b of the intermediate roll 3 and the tapered portion 2a of the work roll 2 have the same tapered shape as in Example 17, and the other tapered portion 2b of the work roll 2 is 0.4
The taper of × 10 ^-3 (per 0.08 mm / 200 mm diameter) was used, and the intermediate roll was shifted in the range of 0 mm to 700 mm. For the specifications of the conventional rolling mill for comparison,
This is similar to the case of Example 17.

Test Results The measurement results of the plate crown are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Table 19 shows the number of times of drawing, plate thickness accuracy and plate crown average value when the invention rolling mill and the conventional rolling mill described above were used to further roll 100,000 tons. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0145]

[Table 19]

[Embodiment 19] FIG. 53 shows a rolling mill in which the barrel length of the work roll 2 in the 6-high rolling mill shown in FIG. 49 is longer than the barrel length of the intermediate roll 3. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A 6-high rolling mill having the configuration shown in FIG. 53 was placed in the third stand of the hot finishing rolling mill, and rolling was performed under the same conditions as the treatment in Example 17 above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the work roll barrel length is 3400 mm, the intermediate roll barrel length is 3000 mm, and the backup roll barrel length is 2300.
In the place of mm, the intermediate roll is provided with the same double-tapered roll taper as that in Example 17, and the work roll is provided with the same single-tapered roll taper as in Example 17, and the intermediate roll is changed from 0 mm. It was shifted in the range of 700 mm. The specifications of the conventional rolling mill for comparison are the same as in the case of Example 17.

Test Results The results of plate crown measurements are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Further, when the invention rolling mill and the conventional rolling mill described above are used to further roll 100,000 tons, the number of times of drawing, the plate thickness accuracy and the plate crown average value are as shown in Table 20. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in both the strip thickness accuracy and the stripability (reduction of drawing).

[0149]

[Table 20]

[Embodiment 20] FIG. 55 shows a rolling mill of the 6-high rolling mill shown in FIG. 51 in which the work rolls 2 are provided with roll-tapered roll crowns. With regard to this rolling mill as well, a comparison was made regarding the distribution of the plate crown with respect to the number of rollings between the case of using this rolling mill and the case of using the conventional rolling mill. Inventive Rolling Mill A six-high rolling mill configured as shown in FIG. 55 was placed in the third stand of the hot finishing rolling mill, and rolling was performed under the same conditions as the treatment in Example 17 described above. The plate crown at a position 25 mm from the edge was measured for every 5 coils of this treatment. Here, the roll size and the shape of the intermediate roll are the same as in Example 19, and the tapered portion 2a of the work roll is set to 0.8 × 10.
^-3 (per 0.16mm / 200mm diameter) and 2b with 0.1 × 10 ^-3 (per 0.02mm / 200mm diameter) taper, and the intermediate roll is shifted from 0mm to 700mm Let The specifications of the conventional rolling mill for comparison are the same as in the case of Example 17.

Test Results The measurement results of the plate crown are shown in FIG. According to the figure, when the rolling mill of the present invention is used, it is clear that even if the target crown is changed, highly precise strip rolling can be performed very close to it.

Further, when the invention rolling mill and the conventional rolling mill described above are used to further roll 100,000 tons, the number of times of drawing, the plate thickness accuracy and the plate crown average value are as shown in Table 21. According to the invention, the invention rolling mill is far superior to the conventional rolling mill in terms of strip thickness accuracy and stripability (reduction of drawing).

[0153]

[Table 21]

[0154]

According to the present invention, a rolled plate having a desired plate crown and an edge drop and having a target plate shape can be obtained with high accuracy, and the yield in the next step can be improved. , Can always perform stable rolling. Further, the life of the intermediate roll and the work roll can be extended.

[Brief description of drawings]

FIG. 1 is a front view showing a rolling mill of the present invention.

FIG. 2 is a diagram showing a roll crown of an intermediate roll.

FIG. 3 is a diagram showing a shift state of an intermediate roll.

FIG. 4 is a control system diagram of a rolling mill.

FIG. 5 is a graph showing a linear pressure between rolls and a plate crown.

FIG. 6 is a graph showing the ratio of the intermediate roll and the backup roll and the maximum linear pressure between the rolls.

FIG. 7 is a graph showing a contact state between rolls regarding a ratio of an intermediate roll and a backup roll.

FIG. 8 is a diagram illustrating bending of an intermediate roll.

FIG. 9 is a graph showing the relationship between the ratio of the intermediate roll and the backup roll and the bending amount of the intermediate roll.

FIG. 10 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 11 is a schematic diagram illustrating a method of supplying lubricating oil.

FIG. 12 is a schematic diagram illustrating a method of supplying lubricating oil.

FIG. 13 is a graph showing the relationship between work roll diameter and crown control amount.

FIG. 14 is a front view showing a rolling mill.

FIG. 15 is a graph showing a distribution state with respect to the number of rolled plate crowns.

FIG. 16 is a graph showing an edge drop generation amount.

FIG. 17 is a front view showing a rolling mill.

FIG. 18 is a schematic diagram showing a contour shape of a taper portion of a roll.

FIG. 19 is a diagram showing a shift state of an intermediate roll.

FIG. 20 is a graph showing a roll-to-roll linear pressure distribution.

FIG. 21 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 22 is a front view showing a rolling mill.

FIG. 23 is a graph showing a distribution state of a plate crown with respect to the number of rolled strips.

FIG. 24 is a front view showing a rolling mill.

FIG. 25 is a schematic diagram showing a contour shape of a taper portion of a roll.

FIG. 26 is a diagram showing a shift state of an intermediate roll.

FIG. 27 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 28 is a front view showing a rolling mill.

FIG. 29 is a graph showing a distribution state of a plate crown with respect to the number of rolled lines.

FIG. 30 is a front view showing a rolling mill.

FIG. 31 is a diagram showing a shift state of work rolls.

FIG. 32 is a graph showing the amount of change in edge drop.

FIG. 33 is a graph showing a distribution state of a plate crown with respect to the number of rolled lines.

FIG. 34 is a graph showing the generation amount of edge drops.

FIG. 35 is a front view showing a rolling mill.

FIG. 36 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 37 is a front view showing a rolling mill.

FIG. 38 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 39 is a front view showing a rolling mill.

FIG. 40 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 41 is a front view showing a rolling mill.

FIG. 42 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 43 is a front view showing a rolling mill.

FIG. 44 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 45 is a front view showing a rolling mill.

FIG. 46 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 47 is a front view showing a rolling mill.

FIG. 48 is a graph showing a distribution state of a plate crown with respect to the number of rolled lines.

FIG. 49 is a front view showing a rolling mill.

FIG. 50 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

FIG. 51 is a front view showing a rolling mill.

FIG. 52 is a graph showing a distribution state of a plate crown with respect to the number of rolled strips.

FIG. 53 is a front view showing a rolling mill.

FIG. 54 is a graph showing a distribution state of the plate crown with respect to the number of rolled lines.

FIG. 55 is a front view showing a rolling mill.

FIG. 56 is a graph showing a distribution state of a plate crown with respect to the number of rolled sheets.

[Explanation of symbols]

 1 Housing 2 Work Roll 2a Work Roll Tapered Part 2b Work Roll Tapered Part 3 Intermediate Roll 3a Intermediate Roll Tapered Part 3b Intermediate Roll Tapered Part 4 Backup Roll 4a Backup Roll Barrel End 4b Backup Roll Barrel End 5 Shift Device 6 shift device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (31) Priority claim number Japanese Patent Application No. 3-189467 (32) Priority date Hei 3 (1991) July 4 (33) Country of priority claim Japan (JP) (31) Priority Claim No. Japanese Patent Application No. 3-189468 (32) Priority Date No. 3 (1991) July 4 (33) Country of priority claim Japan (JP) (31) No. of priority claim Japanese Patent Application No. 3-189469 (32) Hihei 3 (1991) July 4 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-189470 (32) Priority Day Hei 3 (1991) July 4 (33) ) Priority claiming country Japan (JP) (31) Priority claiming number Japanese Patent Application No. 4-942 (32) Priority date Hei 4 (1992) January 7 (33) Priority claiming country Japan (JP) (72) Inventor Kunio Kitamura 1st Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Corporation Technical Research Division

Claims (12)

[Claims] 1. A six-high rolling mill comprising a pair of upper and lower work rolls, an intermediate roll and a backup roll, and at least the intermediate roll among the respective intermediate rolls and work rolls is capable of axial shift. hand,
Each intermediate roll has a barrel length longer than the barrel length of the backup roll such that the barrel end thereof can project outward from the barrel end of the backup roll even in the maximum and minimum shift postures, and the intermediate roll pair is vertically arranged. A 6-high rolling mill with a point-symmetrical roll crown. 2. The 6-high rolling mill according to claim 1, wherein the barrel length of the intermediate roll is 1.2 to 2.5 times the barrel length of the backup roll. 3. The 6-high rolling mill according to claim 1, wherein the barrel length of the work roll is equal to or longer than the barrel length of the intermediate roll. 4. The 6-high rolling mill according to claim 3, wherein the barrel length of the work roll is 1.4 to 2.5 times the barrel length of the backup roll. 5. The roll crown of the intermediate roll is selected from an S-shape, a tapered shape in which the diameter gradually decreases toward one end of the barrel, and a tapered shape in which the diameter gradually decreases toward both ends of the barrel. The 6-high rolling mill according to claim 1 or 2, which is one type. 6. The intermediate roll is provided with an S-shaped roll crown, and the work roll is provided with a tapered roll crown having a diameter gradually decreasing toward one end of the barrel at positions symmetrical with respect to the upper and lower sides thereof. Claims 1, 2, 3
Or the 6-high rolling mill described in 4. 7. The intermediate roll is provided with an S-shaped roll crown, and the work roll is provided with a tapered roll crown having a diameter gradually decreasing toward both ends of the barrel, at positions vertically symmetrical with respect to each other. Claims 1, 2, 3
Or the 6-high rolling mill described in 4. 8. The intermediate roll is provided with a taper-shaped roll crown whose diameter gradually decreases toward one end of the barrel, and the work roll is provided with a taper-shaped roll crown whose diameter gradually decreases toward one end of the barrel. The 6-high rolling mill according to claim 1, 2, 3, or 4, which is provided at positions that are vertically symmetrical with respect to each other. 9. The intermediate roll is provided with a taper-shaped roll crown whose diameter gradually decreases toward one end of the barrel, and the work roll is provided with a taper-shaped roll crown whose diameter gradually decreases toward both ends of the barrel. The 6-high rolling mill according to claim 1, 2, 3, or 4, which is provided at positions that are vertically symmetrical with respect to each other. 10. An intermediate roll is provided with a taper-shaped roll crown whose diameter gradually decreases toward both ends of the barrel, and a work roll is provided with a taper-shaped roll crown whose diameter gradually decreases toward one end of the barrel. The 6-high rolling mill according to claim 1, 2, 3, or 4, which is provided at positions that are vertically symmetrical with respect to each other. 11. An intermediate roll is provided with a taper-shaped roll crown whose diameter gradually decreases toward both ends of the barrel, and a work roll is provided with a taper-shaped roll crown whose diameter gradually decreases toward both ends of the barrel. The 6-high rolling mill according to claim 1, 2, 3, or 4, which is provided at positions that are vertically symmetrical with respect to each other. 12. The work roll has a barrel diameter of 400 to 70.
The 6-high rolling mill according to any one of claims 1 to 11, having a length of 0 mm.