JPS6018498B2 - Rolling mill plate crown control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plate crown control device for a plate material to be rolled in a rolling mill.

When a plate is rolled using a rolling mill, a crown is formed on the rolled plate as is well known.

For example, in hot rolling of a steel plate with a thickness of 2 to 3 sides, the
The value is approximately 00 Am. In other words, there is a difference of 10 degrees between the thickness at the center of the board and the thickness at the edge, and if the minimum thickness is guaranteed, there will be an extra volume corresponding to the crown of the board. . In addition, it is generally desirable that the thickness of the steel sheet be constant for each part; for example, in the case of electric equipment such as motors and transformers that use a large number of laminated electromagnetic steel sheets, differences in thickness may affect assembly work and electrical characteristics. This is especially true as it can have a negative impact on By the way, in order to control the crown to be flat at a desired value, for example, zero or in the middle direction, a roll pending method for work rolls in a four-high rolling mill has been developed and has achieved some results, but this method is limited to the ability to correct the plate crown. Therefore, sufficient effects cannot be expected, especially when the medium of the plate changes to medium.

For example, in the hot rolling of steel plates, the plate material to be rolled is generally rolled according to a schedule called a co-fin schedule, in which it is first rolled to medium width, then wide to medium, and finally fine to fine. When this happens, the roll besoder has little effect on crown control. Therefore, the present applicant first devised a four-high rolling mill in which the effective length of the support roll was shortened and a convex crown was provided on the peripheral surface of the roll, and filed an application for the same. According to this rolling mill, it is possible to effectively control the plate crown even if the inside of the plate changes, and it is possible to provide high-quality plate materials in a timely manner. The present invention further improves this and makes it possible to achieve good crown control for fluctuations in the sheet and other factors by performing appropriate control in combination with a roll bender. In the plate crown control device for a rolling mill of the present invention, the effective body in contact with the work roll has one type of length shorter than the work roll body length, and the effective body has a roll diameter of 1. In addition, it is equipped with a reinforcing roll with a large convex crown that is larger than the ship's side.
a rolling mill in which the work rolls are provided with a roll pending device; a first computing unit that receives input of the sheet thickness, exit side sheet thickness, and target shape value and calculates the amount of sheet crown change; a second computing unit that receives the input plate thickness and exit side plate thickness and calculates the exit side plate crown value; and a third calculator that receives the measured values of the rolling load in the plate, and the exit side plate crown value and calculates the optimum roll pending force. The present invention is characterized by comprising a computing unit and a device for controlling the roll pending device so that the actual roll pending force becomes equal to the optimum roll pending force, which will be described in detail below with reference to the drawings. FIG. 1 shows the basic form of a rolling mill previously proposed by the applicant.

In this figure, 1 is a plate material to be rolled, 2a and 2b are work rolls, and 3a and 3b are reinforcing or supporting rolls. The main difference between this rolling mill and the known four-high rolling mill is that the reinforcing roll 3
a and 3b, the diameter of this roll is smaller from the end of the roll body to the constant steel 1 as shown in the figure, and the diameter of the middle part of length L is larger, so that the effective and It is the same part, and a convex crown is attached around this part. Also suitable for reinforcing rolls in conventional 4-high rolling mills.

- A convex crown is provided in consideration of roll wear, etc., but its size is approximately 0.2 willow in diameter at most. On the other hand, the reinforcing rolls 3a and 3b have a roll diameter of at least 1. Cape Qiu or above, preferably 2. Adds a convex roll crown to the side of the ship. As illustrated in Fig. 2 a to e, there are various shapes of roll crowns, such as trapezoid a, polygonal line b, sinusoidal curve c, parabola d, and e, which is a shape in which a crown is attached to the trapezoid of a above. is possible, but
Preferably, as shown in e, the effective body length L is regulated by either the medium elongation limit or the rolling limit under the rolling conditions for the largest plate of the material to be rolled (for example, for a hot strip rolling mill with a body length of approximately 8 feet). In finish rolling, a roll crown (for example, △R = 1
It is most effective to provide ribs in terms of the contact length during rolling, that is, the actual effective roll body length, and the plate crown characteristics.

Regarding the effective body length L, in any plate, the shorter the length, the smaller the plate crown. However, if the thickness is too large, medium elongation will occur in the rolled plate material, and the stress between the work roll and the reinforcing roll will increase, making spalling more likely to occur. Therefore, the minimum effective roll body length L is regulated by the medium elongation limit and the rolling limit. In the rolling mill shown in FIG. 1, the work roll 2a is
, 2b try to remain above and below, the reinforcing roll 3a,
3b suppresses this, and the amount of sagging is greatest at the center, but since the reinforcing rolls 3a and 3b have the largest diameter at the center, they can effectively suppress this sagging.

In addition, the amount of sag increases as the rolling load increases, but at this time, due to their elastic deformation, the reinforcing rolls 3a, 3b come into contact with the work rolls 2a, 2b over a wider contact area, and eventually, automatically according to the rolling load. It becomes a variable torso length roll that increases or decreases the torso length. Since the rolling load corresponds to the inside of the sheet, the above also applies when the inside of the sheet changes. As a result, this rolling mill can reduce and control the plate crown of the rolled plate material even if the rolling reduction rate, plate thickness, etc. change.
Furthermore, it is important that the reinforcing rolls 3a, 3b are not in contact with the work rolls 2a, 2b in the predetermined ranges 1 at both ends, and as a result, the roll pending force is not restrained by the support roll at the ends of the work rolls, so that there is no contact with the work rolls 2a, 2b. Good,
Crown control by roll bender is effectively performed. Crown control using a roll bender is fairly effective, as it is long-responsive within the effective range. Therefore, this is effective for various boards,
This is a big advantage. A 6-high rolling mill has also been proposed in which an intermediate roll is added to the 4-high rolling mill, and the intermediate roll is shifted from side to side. As it becomes necessary, it is inevitable that it will become larger and more complex. Incidentally, there are various factors that determine the amount of crown, in addition to the rolling load, such as the initial profile of the work roll, changes in it due to thermal expansion, wear, and the like. In order to appropriately deal with these factors and always obtain the desired sheet crown, the rolling mill shown in FIG. 1 alone is still insufficient and requires appropriate control and adjustment. In view of the above, the present invention attempts to perform extremely effective and reliable crown control by using the rolling mill shown in FIG. 1 in conjunction with a roll bender. Next, the present invention will be explained in detail using examples. FIG. 3 shows the relationship between the roll pending force F and the plate crown Cr. As shown in this figure, F and ○ have a linear relationship with B in the plate and rolling load P as parameters. Moreover, FIG. 4 is a graph showing the relationship between the plate crown and the shape.

The horizontal axis shows the difference △cr between the exit side crown ratio Cri/hi and the entry side crown ratio Cri-,/hH. Therefore, the origin △doq=0 indicates rolling with a constant crown ratio, and in this case The shape is good, and Δs=0. Here, Δs is the difference in elongation in the longitudinal direction between the central part of the plate and the ends of the plate, which is determined from the plate shape, and is a shape parameter. If the difference △ melt is positive, this means that the crown ratio has increased, that is, rolling with increased edge elongation has been carried out, and if the difference △ cr is negative, this means that the crown ratio has decreased, that is, the rolling has been carried out with an increase in edge elongation. This means that some rolling has been done. In this case), Cri, Cri-, indicate each plate crown on the exit side and inlet side, and hi, hi-. indicate each plate thickness on the exit side and inlet side. As shown in this figure, even if rolling with edge elongation or medium elongation, that is, rolling with △ melt > 0 or △ melt < 0, will result in edge elongation or medium elongation, that is, shape defect △. Instead, this is reflected in △dos through the parameters of plate thickness h and medium B. In other words, as shown in the figure, when the board thickness is 3 legs, a larger △s occurs than when hj = 6 skins, and even with the same board thickness, B in the board
The wider one is larger than the narrower one. The purpose of this invention is to utilize the relationship according to the present invention to achieve more effective and appropriate plate crown control in the rolling mill shown in FIG. 1, and an embodiment thereof is shown in FIG. In Figure 5, 1, 2a and 2b, and 3
3a and 3b are a rolled plate material, a work roll, and a reinforcing roll of the rolling mill shown in FIG. 4 has a roll pending rhombus, which is also provided on the pond side of the work rolls 2a and 2b, although not shown.

5 is a plate width detector, 6 is a detector for the entry side plate crown, 7 to 9
10 is a comparator, 111 is a roll pending force control device, 12 is a rolling load detector, and 13 is a roll pending force detector.

To explain the operation, in addition to the actual measurement value B in the plate from the detector 5, the outlet side plate thickness hi and the target shape △gos are input to the calculator 7, and using FIG. 4, the plate crown change amount A'q is calculated. is calculated and output to the arithmetic unit 8.

The calculator 8 receives the input plate thickness hi- and the outlet plate thickness hi in addition to the △cr, the measured value Cri- of the inlet crown from the detector 6, and calculates the outlet plate crown Cri using the following formula. and outputs this to the arithmetic unit 9. Cri=hi{△
The calculator 9 calculates the optimum roll pending force F based on the exit plate crown Cri, plate middle B, and rolling load P based on the relationship shown in Figure 3.
o is determined and outputted to the comparator 10.

The comparator 10 calculates the difference between this Fo and the actually measured roll pending force from the detector 13, and transmits this difference ER to the control device 11.
The control device adjusts the roll pending force generated by the roll pending device 4 so that the difference ER becomes zero. This equipment uses a rolling mill that itself has good crown control ability, and uses a roll bender to reinforce the crown control, so it can more appropriately match target values even against changes in the plate and other areas. Crown control can be performed to Furthermore, since this device does not perform closed-loop control of the crown, the control system is simple, and since actual values are used for the rolling load in the plate, it has the advantage of high accuracy despite the simple control system.

[Brief explanation of drawings]

Figure 1 is a schematic side view showing the structure of the previously proposed rolling mill;
Figures a to e are explanatory views showing various shapes of the roll crown, Figures 3 and 4 are characteristic diagrams, and Figure 5 is a block diagram showing an embodiment of the present invention. In the drawing, 2a and 2b are work rolls, 3a and 3b are reinforcing rolls, 4 is a roll pending device, and 7 is a mathematical model of the relationship between △gos and △dissolution shown in Fig. 4 (hi and Bi are parameters). Crown ratio change from △dos △・
A device that calculates and outputs cr, 8 is the actual measured value of the entrance crown C
A device that calculates and outputs the exit target plate crown Cri from the input plate thickness h, -, and the required crown ratio change △cr; 9 uses the target plate crown Cri, plate width B, and rolling load P. 10 is a device that compares the actual value F of the roll pending force with the target pending force Fo and outputs the deviation amount Ea; 11 is a device that calculates and outputs the roll pending force Fo by the deviation amount ER of the roll pending force. A control device 13 is a roll pending force detector that operates to control the pending force and make the deviation amount ER zero. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A reinforcing roll in which the effective body in contact with the work roll has one type of length shorter than the work roll body length, and the effective body has a large convex crown with a roll diameter of 1.0 mm or more. a rolling mill in which the work rolls are provided with a roll bending device; a first computing unit that receives sheet width, exit side sheet thickness, and target shape values and calculates sheet crown change amount; a second arithmetic unit that receives the side crown, inlet side plate thickness, and outlet side plate thickness and calculates the outlet side plate crown value;
a third computing unit which calculates the optimum roll bending force by inputting the plate width, the measured value of the rolling load, and the above-mentioned output side plate crown value; A plate crown control device for a rolling mill, comprising a device for controlling the roll bending device.