JPH07164014A - Device and method for rolling plate - Google Patents

Abstract

PURPOSE:To dynamically change a pass line during rolling and to efficiently manufacture a plate without camber by respectively providing highly responsive screw down devices with which a vertical position is controlled in upper and lower roll systems. CONSTITUTION:The upper roll system and the lower roll system are respectively provided with the highly responsive screw down devices 7, 8 with which the setting and control of the upper and lower roll positions are enabled. Thus, the pass line is controlled without changing a roll gap. In this way, the pass line is vertically symmetrically set for every pass in reverse rolling. Roller tables 4 with which a rolled stock 3 is fed and transported are arranged before and behind a rolling mill. The nearest roller table 4 to the rolling mill is provided with a load sensor 9 and, when the load is over the preset ceiling value, the pass line is raised by controlling the screw down devices 7, 8 for the upper and lower rolls.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate rolling mill capable of controlling warpage and a method of operating the same.

[0002]

2. Description of the Related Art A warp that occurs during the rolling of a plate material has a great influence on the productivity of products, such as a reduction in rolling efficiency, an occurrence of equipment accidents, and an increase in a refining process. For example, if the warp of the plate tip exceeds a certain limit, it becomes impossible to bite the next pass, resulting in a reduction in rolling efficiency. When a larger warp occurs, the rolling equipment may be damaged due to the collision of the plates. In this case, not only the plate itself loses product value,
It causes a lot of damages such as production stop and repair of rolling equipment. In addition, regarding the adjustment, it is necessary to correct the warp by a leveler or the like, and in an extreme case, the defective portion may have to be cut.

However, the cause and mechanism of occurrence of this warp are not always clarified.
It is generally said that the following rolling conditions are the cause. Vertical difference of work roll diameter Vertical difference of roll peripheral speed Vertical difference of friction coefficient Vertical difference of deformation resistance (due to vertical temperature difference, etc.) Pickup amount Of these conditions, the pickup amount changes the inlet and outlet plate thicknesses. It is considered to be an important condition that changes from time to time. A method for controlling the pickup amount is Japanese Patent Application No. 61-
No. 280140 and Japanese Patent Application No. 3-198838.

[0004]

Problems to be Solved by the Invention Japanese Patent Application No. 61-2
No. 80140 considers only the pickup amount H. However, as will be described later, when the warp is controlled, it is necessary to consider the entrance side plate thickness and the exit side plate thickness under geometric conditions, and therefore the pick-up amount H alone cannot sufficiently control the warp. . Moreover, the specific means is not disclosed.

With respect to Japanese Patent Application No. 3-198838, only the description of control by the pickup amount is limited, and the specific control method is completely unknown. Further, there has not been developed a rolling mill having a highly responsive upper and lower roll reduction device capable of keeping the roll gap constant in response to the fluctuation of the pickup.

In view of the above points, an object of the present invention is to provide a rolling apparatus and a rolling method using the rolling apparatus, which can efficiently produce a plate without warping at low cost.

[0007]

In order to solve such a problem, the present invention is characterized by a rolling mill having a down-rolling device in each of the upper and lower roll systems and capable of pass line control. That is, the gist of the present invention is as follows.

(1) In a sheet rolling machine having at least upper and lower roll systems and a rolling roller table provided at the front and rear of the rolling machine, in each of the upper and lower roll systems, setting of the vertical position with high responsiveness, A plate rolling apparatus comprising a controllable rolling down apparatus. (2) The strip rolling apparatus according to (1), wherein the reduction device is a hydraulic reduction device. (3) A load sensor is provided on a table roller near the rolling table of the roller table (1)
Alternatively, the plate rolling apparatus according to (2).

(4) At least upper and lower roll systems are provided,
In a rolling method using a rolling mill equipped with a rolling down device capable of setting and controlling the vertical position with high responsiveness to each of the upper and lower roll systems, and a rolling method using a rolling mill equipped with a roller table before and after the rolling mill, the rolling methods are vertically symmetrical. A plate rolling method comprising setting a pass line and rolling a material to be rolled. (5) A rolling mill having at least upper and lower roll systems, each of the upper and lower roll systems being provided with a reduction device capable of setting and controlling the vertical position with high responsiveness, and a roller table before and after the rolling mill. In the rolling method using the rolling device described above, when rolling the rolled material, the pass line is dynamically controlled during rolling. (6) The sheet rolling of (4) or (5), characterized in that a load sensor is provided on the roller of the roller table in the immediate vicinity of the rolling mill and the pass line is raised when the output of this sensor exceeds a predetermined value. Method.

[0010]

The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an example of the rolling mill of the present invention. The rolled material 3 conveyed onto the roller table 4 is rolled by the upper work roll 1 and the lower work roll 2 to a predetermined plate thickness. Upper roll system is upper work roll 1 and upper backup roll 5
The lower roll system includes a lower work roll 2 and a lower backup roll 6. Upper roll type,
Each of the lower roll systems has a pressure reducing device 7, 8, preferably a hydraulic pressure reducing device capable of setting and controlling the upper and lower roll positions with high responsiveness. Therefore, it is possible to control the pass line without changing the roll gap. The roller table 4 is arranged in front of and behind the rolling mill, and supplies and conveys the material to the rolling mill. A load sensor 9 is preferably installed on the table roller closest to the rolling mill.

As a result of the ingenuity, the inventors have made the work roll diameter, roll peripheral speed, friction coefficient, and deformation resistance vertically symmetrical, and corresponding to the entrance side plate thickness h ₀ and the exit side plate thickness h ₁ . If the pickup amount H during rolling is set to the condition of formula (1),
It was found that the geometrical condition at the time of biting is also vertically symmetrical, and it is possible to manufacture a plate without warpage. Pickup amount H = Δh _U = Δh _L = Δh / 2 = (h ₀ −h ₁ ) / 2 (1) Here, the entrance side plate thickness is h ₀ , the exit side plate thickness is h ₁ , the lower work roll 2 and the roller. The height difference H from the upper end of the table 4 is the pickup amount, the reduction amount on the upper work roll 1 is Δh _U , the reduction amount on the lower work roll 2 is Δh _L , and the total reduction amount is Δh.

FIG. 2 shows an outline of rolling when the formula (1) is satisfied. Since the amount of reduction Δh _U by the upper work roll 1 and the amount of reduction Δh _L by the lower work roll 2 are equal, there is no vertical difference in the elongation in the longitudinal direction due to rolling, and rolling without warpage is possible. Therefore, regardless of the tandem rolling or the reverse rolling, if the rolling satisfying the expression (1) is performed, the warpage does not occur in the rolling.

As mentioned above, Japanese Patent Application No. 61-28014
In No. 0, only H is used as the control end of the geometric condition, and H
Although it is disclosed that warping does not occur if is controlled to a set value, geometrical conditions cannot be made vertically symmetrical only by controlling H. For example, the same H is vertically symmetrical in the case of FIG. 3A, but is vertically asymmetric in the case of FIG. 3B, which causes warpage.

In the rolling mill of the present invention, as an example of its operating method, it is possible to set up and down symmetrical pass lines for each pass of reverse rolling. As shown in FIG.
The pickup amount H ₁ of the pass is set according to the equation (1) as in the equation (1) ′. Pickup amount of H ₂ second pass, entry side thickness h _1, because thickness at delivery side is h _2,
Set by equation (2). The third and subsequent passes may be similarly set. By using this operation method, the vertical symmetry of the geometric conditions is satisfied for each pass, and rolling can be performed without warpage in all passes. Pickup amount H ₁ = Δh / 2 = (h ₀ −h ₁ ) / 2 ………… (1) ′ Pickup amount H ₂ = Δh / 2 = (h ₁ −h ₂ ) / 2 ………… … (2)

The conventional rolling mill does not have a mechanism for synchronously moving the upper and lower roll systems up and down so as not to give a disturbance to the plate thickness, so that the above-described operating method is executed during rolling. Is impossible. That is, if the pickup is changed in the conventional rolling mill, the roll gap is greatly changed, and a plate having a very large plate thickness variation is manufactured.

On the other hand, since the rolling mill of the present invention is equipped with the rolling devices having high responsiveness to the upper and lower roll systems, respectively, as described above, the upper and lower roll systems can be moved in synchronism with each other. The pass line can be changed dynamically without changing the roll gap. Therefore, when warpage occurs during rolling or when warpage is predicted to occur, the pickup amount H can be set or controlled correspondingly. That is, the relationship between H and the warp direction is as follows. When H> Δh / 2: Warp When H <Δh / 2: Warp

When H> Δh / 2, the warp is caused by
As shown in FIG. 5, the reduction amount Δh _L in the lower work roll 2
Is larger than the reduction amount Δh _U in the upper work roll 1, and therefore the elongation of the material of the lower surface portion of the rolled material 3 is large. If H <Δh / 2, the opposite is true. Since the quantitative relationship between H and the amount of warp varies depending on each rolling condition, it may be obtained as necessary.

Further, when H <Δh / 2, a large load is applied to the roller table 4, so that the roller table 4 may be damaged in some cases. In this case, if a load sensor is installed on the roller closest to the mill, when the load sensor output exceeds a preset upper limit value, it is possible to control the upper and lower roll rolling down devices to raise the pass line. .

Further, as shown in FIG. 6, even when the plate thickness of the rolled material changes during rolling, the pass line may be changed during rolling based on the equation (1).

[0020]

Examples and Comparative Examples Using a rolling machine with a work roll diameter of 900 mm, a slab having a width of 1760 mm and a length of 4000 mm was rolled to a plate thickness of 50 mm while changing the entrance side plate thickness (80 to 110 mm). In the comparative example, the pickup amount was fixed (H = 20 mm), and in the example, the pickup amount was changed for each rolling based on the formula (1), and the pass lines were set to be vertically symmetrical. The roll peripheral speed is 3.0 m / s
The friction coefficient and the deformation resistance were adjusted so that no vertical difference would occur. The result is shown in FIG. 7. In the comparative example, the geometrical condition happens to be vertically symmetric h ₀ = 90
It can be seen that, except for mm, a large warp has occurred. On the other hand, in the embodiment in which the pass line is set so that the geometric condition is vertically symmetrical for each rolling, the warp amount is extremely small.

[0021]

As described above, according to the present invention, it is possible to efficiently manufacture a warp-free plate.
It has the effect of being able to mass-produce plates with excellent shapes.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a rolling mill of the present invention.

FIG. 2 is a diagram showing pass line setting when geometric conditions are vertically symmetrical.

FIG. 3 is a diagram showing an influence of a plate thickness on an entrance side on a geometric condition.

FIG. 4 is a diagram showing an example in which the present invention is applied to reverse rolling.

FIG. 5 is a diagram showing an influence of a pass line setting on a warp direction.

FIG. 6 is a diagram showing an example in which the plate thickness fluctuates midway.

FIG. 7 is a diagram showing the influence of the thickness of the incoming plate on the amount of warpage.

[Explanation of symbols]

 1 Upper work roll 2 Lower work roll 3 Rolled material 4 Roller table 5 Upper backup roll 6 Lower backup roll 7 Rolling down device 8 Rolling down device 9 Load sensor

Claims (6)

[Claims] 1. A plate rolling machine having at least upper and lower roll systems, and a rolling apparatus provided with rolling roller tables before and after the rolling system, wherein each of the upper and lower roll systems sets and controls the vertical position with high responsiveness. A plate rolling apparatus, which is equipped with a rolling down device capable of performing the above. 2. The strip rolling apparatus according to claim 1, wherein the reduction device is a hydraulic reduction device. 3. The plate rolling apparatus according to claim 1, wherein a load sensor is provided on a table roller near the rolling table of the roller table. 4. A rolling mill having at least upper and lower roll systems, and each of the upper and lower roll systems having a reduction device capable of highly responsively setting and controlling the vertical position, and a roller table before and after the rolling mill. A rolling method using a rolling apparatus including: a sheet rolling method, in which pass lines are symmetrically set to roll a material to be rolled. 5. A rolling mill having at least upper and lower roll systems, and each of the upper and lower roll systems having a reduction device capable of setting and controlling the vertical position with high responsiveness, and a roller table before and after the rolling mill. In the rolling method using the rolling apparatus having the above, when rolling a rolled material, the pass line is dynamically controlled during rolling. 6. The strip rolling according to claim 4, wherein a load sensor is provided on a roller of the roller table, which is located in the immediate vicinity of the rolling mill, and the pass line is raised when the sensor output exceeds a predetermined value. Method.