JPH0130564B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention reduces the tension applied to the rolled material as much as possible when adjusting the roll crown by moving the back-up roll in the axial direction, and stabilizes the rolled material. The present invention relates to a method and apparatus for adjusting roll crown in a four-high rolling mill intended for rolling.

(Prior Art) Many inventions have been proposed in the past that attempt to adjust the roll crown of a work roll by moving an intermediate roll in the axial direction (for example, Japanese Patent Application Laid-Open No.
- No. 3061, JP-A-50-151748). However, although these inventions all move work rolls in a four-high rolling mill in the axial direction,
The axis diameter of the back-up prowl was less than 70% of the trunk diameter.

(Problem to be solved by the invention) In other words, the most important point when continuously rolling a material is:
The rolling material must be constantly and stably rolled at a predetermined position of the rolling rolls. For example, as shown in FIG. 1, the rolled material 2 needs to be stable on the rolling center line of the work rolls 1 and 1a, but if no adjustment means are provided, the rolled material moves as follows.

(1) When the rolled material moves to the right or left as shown by arrow 3 in Figure 1.

In this case, the rolled product becomes thick, uneven, and meandering. Such horizontal movement is thought to be caused by poor surface polishing of the work roll, misalignment of the centers of the roll cylinder and roll axis, or cases where the center lines of the upper and lower rolls are non-parallel.

(2) When the rolled material moves to the right or left as shown by arrows 4 and 5 in Figure 1 and falls off the work roll.

This case mainly occurs when the roll shaft diameter is 80% or less of the roll body diameter, or when the roll rigidity is reduced due to a multi-high rolling mill.

In the former case, as shown in FIG. 2, the roll body a forms discontinuous curves l ₁ , l ₂ , l ₃ with respect to the roll axis b.
If the roll body is bent with a
Since the rolling material 2 has a linear inclination, it becomes unstable due to displacement of the rolled material 2, and it slides in the direction of the arrow 6 and falls off from the roll body. Further, in the case of a multi-high rolling mill (FIG. 3), the rigidity of the rolls is extremely reduced. The reason for this is that the contact portion between the rolls changes from line contact to surface contact, and as a result, the surfaces of the body portions of the work rolls 7, 7a tend to tilt. Particularly in the case of a six-high rolling mill as shown in FIG. 3, the rolling material becomes unstable, so in order to correct this, a strong tension is applied to the rolled material as indicated by arrow 8 in FIG.
The same applies to four-high rolling mills, but the fourth
The six-high rolling mill shown in the figure must apply stronger tension. This means that the greater the degree of instability, the greater the tension must be to correct it.

(Means for Solving the Problems) However, in this invention, the diameter of the roll shaft is made as large as possible with respect to the diameter of the roll trunk, and the roll trunk a and the roll shaft b are deformed into a continuous line l. (Figure 5),
And by adjusting the roll crown by sliding the back up roll of the four-high rolling mill in the axial direction,
This improves the instability that occurs when adjusting the roll crown of conventionally known six-high rolling mills or four-high rolling mills, and enables stable continuous rolling with relatively low tension.

The ratio of roll body diameter to roll shaft diameter in conventional four-high rolling mills is usually 60% to 70%, and if this ratio is increased, it becomes impossible to insert, assemble, or remove the work roll, and the back-up roll and work roll are separated. It was considered impossible to construct the bridge because the bearings would get in the way of each other. On the other hand, increasing the ratio of the roll shaft diameter to the roll body diameter is considered an essential requirement in order to maintain continuity in roll deflection (as a result of experiments, a ratio of 85% or more of the shaft diameter to the roll body diameter is practical). (90% to 95% was recognized as suitable). It is preferable that the ratio is 100%,
When the ratio is 100% (the body and shaft are the same thickness), the back-up roll is always in contact with the body of the work roll, making it impossible to adjust the roll crown. Therefore, in practice, this ratio should be set at 85% to 95% as mentioned above.
That is to say. However, for the roll body diameter,
If the diameter of the roll shaft is increased, there is a risk that the work roll bearing and the backup roll bearing will collide with each other, making it impossible to erect the work roll. Therefore, in this invention, the work roll is constructed so that it can be moved in and out from a direction perpendicular to the roll axis, thereby solving the above problem. In other words, the work roll can be stably erected by shifting the installation positions of the work roll bearing and the back-up roll bearing, and by attaching a thrust receiver and a longitudinal support member to the work roll bearing. did it.

If you try to adjust the crown by sliding the back-up roll of a conventional four-high rolling mill in the axial direction, the distance L between the reaction force points should be determined by taking into account the amount of left-right sliding, as shown in Figure 6. It has to be quite long. However, since the increase in the distance L between the reaction force points is proportional to the cube of the amount of roll deflection, the rigidity of the rolling mill in the case shown in Fig. 6 becomes extremely poor, making it practically unusable as a rolling mill. It had been. Therefore, it has been considered impossible to adjust the roll crown by sliding the back up roll in the axial direction in a four-high rolling mill, and it has not been put to practical use in this type of industry around the world.
For example, if tension is applied to the rolled material in order to adjust the instability of the rolled material due to a decrease in roll rigidity, the tension value must be increased by at least 50% of the tension value applied by a conventional rolling mill. It won't happen. Furthermore, the roll shaft diameter is 85% compared to the roll body diameter.
% (or less than 70% in the conventionally known method), the amount of deflection of the back-up roll increases, so even if the screw is screwed down to adjust the gap, the reduction effect is extremely poor, making it practically unusable. It was estimated that it would become unbearable.

For example, Fig. 7 is a graph of roll pressure force and roll gap variation. If a steel material with a thickness of 1 mm is rolled with the upper and lower rolls in contact and the gap is set to 0, then the roll rigidity line a, b and the plasticity curve c, when the roll stiffness is high, if you read the intersection O of lines a and c on the horizontal axis, it will be 0.25 mm, and the thickness will be
It can be seen that it is rolled to 0.25mm. On the other hand, if you read the intersection O ₁ of lines b and c on the horizontal axis, it will be 0.9 mm, and the thickness will be 0.9 mm.
It can be seen that it is rolled to mm. That is, depending on the roll rigidity, one roll material can be rolled to a thickness of 0.25 mm, while the other roll material can only be rolled to a thickness of 0.9 mm. In both cases, it was found that since the screw was screwed down to the roll gap O, the reduction in the latter case could only be expected to be 0.1 mm at most. The above mentioned the limit of reduction, but the decrease in roll rigidity also affects rolling accuracy as follows. That is, as shown in FIG. 8, it is clear at first glance from FIG. 8 that in the reduction errors h and h ₁ of the rolled material due to the roll rigidity lines a and b and the plasticity curves c and d, h<h ₁ . It can be seen from this graph that the rolling accuracy decreases as the roll rigidity decreases. As mentioned above, it is practically impossible to adjust the roll crown by sliding the back-up roll in the axial direction using a conventional four-high rolling mill due to problems with reduction of the rolled material and rolling accuracy. It turns out that there is something. In other words, if the amount of change in deflection of the back-up roll is greater than the amount of bending applied to the work roll, roll crown adjustment will not be possible. If an attempt is made to solve this problem by increasing the tension value of the rolled material, the following problems arise.

(1) Stable continuous rolling cannot be achieved unless a tension is applied that is 1.5 times the tension used in a normal four-high rolling mill (a value close to the breaking point of the material). However, such implementation may cause troubles such as breakage of the rolled material for some time, and the yield of rolled products will deteriorate.

(2) If a rolled material is wound under tension close to the tensile breaking force, there is a risk that the compressive strength of the winding drum will be exceeded, and the rolled product will wrinkle in the area near the drum. Especially when the product thickness is 0.1mm
If the thickness is less than that, the effect of the wrinkles will remain until the final wound portion (the outermost periphery of the wound product), and there is a risk that the product will be defective, and this cannot be improved even by rewinding.

As mentioned above, rolling instability cannot be improved by increasing the tension value during rolling. The problems explained above can be solved by changing the roll shaft diameter to the roll body diameter, as proposed in this invention.
It has been found that the inconvenience caused by this is fixed at 85% to 95% and can be solved by changing the direction in which the roll is taken out. Therefore, according to the present invention, the stability of a four-high rolling mill (compared to a six-high rolling mill) is maintained as is, and the causes of instability are eliminated, resulting in high reduction and high precision rolling. The crown was made adjustable.

(Example) That is, the present invention will be described with reference to an apparatus for implementing it. In FIG. 9, back-up rolls 11, 11a, in which the diameter of roll shafts 9, 9a is 90% of the diameter of roll cylinders 10, 10a, are installed on a roll stand 12 so as to be rotatable and slidable in the axial direction. The work rolls 13 and 13a are rotatably installed in the same vertical plane between the up rolls 11 and 11a, and thrust receivers 14 and 14a are freely adjustable in the left and right axial directions of the work rolls 13 and 13a. Supports 15 and 15a are installed so as to be adjustable in the direction of right angles (FIG. 12), and reference numerals 16 and 17 in the figure are adjustment screws. The backup roll 11,
One end of 11a has universal joints 18, 18.
a, 19, 19a and spline pipes 20, 20a
and are connected to drive shafts 22, 22a via spline shafts 21, 21a. Further, the lower ends of pressurizing screws 24, 24 are in contact with the bearing casings 23, 23 of the backup rolls 11, 11a. In the above examples, backup roll 1
Drive plate 2 rotatably attached to one end of 1, 11a
One end of piston rods 26, 26 is screwed to both ends of the piston rod 5, and a piston 27 provided at the other end of the piston rod 26 is loosely fitted into a hydraulic cylinder 28. Therefore, one side c section (the first
When pressurized oil is fed into the piston 27 (Fig. 0), the piston 27 moves in the direction of the arrow 29, and the backup roll 11 also slides in the same direction. Contrary to the above, when pressurized oil is fed to the other side d portion of the hydraulic cylinder 28, the piston 27 moves in the direction of the arrow 30, and the backup roll 11 also slides in the same direction. That is, by changing the feeding direction of pressurized oil to the hydraulic cylinder 28, the sliding direction of the back-up rolls 11, 11a can be changed, and by adjusting the feeding amount of pressurized oil, the sliding direction of the back-up rolls can be changed. The amount of movement can be adjusted.

However, the axial drive mechanism of the backup roll is not limited to the specific structure using the hydraulic cylinder.

(Effects of the Invention) That is, according to the method of the present invention, the diameter of the shaft portion of the back roll of a four-high rolling mill is set to 85% or more of the diameter of the body portion.
Since it is set to 100% or less, the back-up roll is deformed in a continuous curve, and the rolled material can be continuously rolled in a stable state. Therefore, there is no need to apply excessive tension to the rolled material, and material breakage during rolling can be avoided.
This has the effect of alleviating problems such as damage to winding equipment, wrinkles in products, and reduced yield. Further, according to the device of the present invention, the shaft diameter of the back-up roll is set to 85% or more and 100% or less of the trunk diameter, and
Since an axial sliding device is connected to one end of the shaft and is rotatably installed, the back-up roll can slide in the axial direction while rotating, and the roll crown of the work roll can be adjusted. In addition, since the work roll is installed so that it can be moved in and out from the direction perpendicular to the axis, the work roll can be easily removed even though the shaft diameter of the back-up roll has been increased.
This has the effect of allowing construction without interfering with the sliding movement of the back-up roll. Since thrust receivers are provided at both ends of the work roll and supports are provided in a direction perpendicular to the axis, there is also the effect that the work roll can be erected at a predetermined position with high precision.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing that the rolled material becomes unstable during continuous rolling. Figure 2 is also a diagram showing the instability of the rolled material in a conventional rolling mill. Figure 3 is a theoretical diagram of a six-high rolling mill. , FIG. 4 is a side view illustrating the state in which tension is applied to the rolled material in a six-high rolling mill, FIG. 5 is an explanatory diagram showing the deformed state of the back-up roll of the present invention, and FIG. An explanatory diagram of the rolling mill, Fig. 7 is a graph of roll pressure and roll gap variation, Fig. 8 is a graph illustrating roll pressure and material thickness error, and Fig. 9 is a part of the apparatus for implementing this invention. FIG. 10 is a front view with parts omitted, and FIG.
The same figure is a sectional view showing the thrust receiver of the work roll, and FIG. 12 is a partially enlarged sectional view showing the mounting state of the support. 9, 9a... Roll shaft, 10, 10a... Roll cylinder, 11, 11a... Backup roll, 13,
13a... Work roll, 14, 14a... Thrust receiver, 15, 15a... Support tool.

Claims (1)

[Claims] 1. A back-up roll whose shaft diameter is 85% or more and 100% or less of the body diameter is slid in the axial direction to change the contact position with the work roll, adjust the roll crown, and adjust the roll crown. is a method for adjusting the roll crown in a four-high rolling mill, which is characterized in that it is installed so that it can be inserted and removed from the direction perpendicular to the axial direction. 2. A pair of back-up rolls having a shaft diameter of 85% or more and 100% or less of the trunk diameter are rotatably installed in the housing, and an axial sliding device is connected to the back-up roll shaft, and the back-up rolls are A pair of work rolls is rotatably installed inward through an axial position adjustment device, and the pair of work rolls is installed between the left and right bearings of the back-up roll in order to be able to be inserted and removed from the direction perpendicular to the axis. A roll crown adjustment device for a four-high rolling mill, characterized in that the device is housed and installed in a four-high rolling mill. 3 Adjust the shaft diameter of the back-up roll to 90% of the body diameter.
A roll crown adjusting device for a four-high rolling mill according to claim 2, wherein the rolling mill is 95%. 4. Claim 2, wherein the axial sliding device combines a drive plate mounted at right angles to the axis of the back-up roll, and a hydraulic cylinder with the drive plate installed parallel to the axis of the back-up roll. A roll crown adjustment device in the four-high rolling mill described above. 5. The work roll erection adjustment device is provided with a thrust receiver that is adjustable in the axial direction, and a front-back support that is adjustable in the front-back direction.
A roll crown adjustment device for a four-high rolling mill as described in 2.