JP3297369B2 - Plate thickness control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a thickness of a sheet material when it is rolled.

[0002]

2. Description of the Related Art Localization control and absolute value control are known as one of automatic control methods for setting a sheet thickness to a target sheet thickness when a sheet material is rolled by a rolling mill. In the localization control, a roll is set to a predetermined roll-down position by a roll-down device provided in a rolling mill, and then the roll-down position is kept constant during rolling of the sheet material.

[0003] The setting of the rolling position by the rolling device is as follows.
When the plate material is performed before the bite between the rolls,
In some cases, the sheet thickness at that time is obtained from the reaction when the sheet material is caught between the rolls, and then the sheet thickness is determined based on the sheet thickness. On the other hand, the absolute value control uses a gauge meter method to calculate the thickness of the sheet during rolling, thereby sequentially controlling the pressing device to maintain the sheet thickness at the target sheet thickness. It is.

Here, the gauge meter method is described as follows. "The thickness of a roll after rolling is determined by the roll gap during rolling, and the roll gap during rolling is determined by the roll gap under no load and the deformation of the rolling mill under load. , The amount of deformation of the rolling mill is determined by the rolling load. "
A method for performing a predetermined operation. By the way, in the above-mentioned localization control, the setting of the rolling-down position is based on the movement amount of the hydraulic actuator or the screw-down screw etc. which the rolling-down device has as a reference. Since there is a tendency to reduce the setting accuracy, in actual rolling sites, absolute value control, which makes it easier to set the plate thickness of the plate material to the target plate thickness than this localization control, is often used.

[0005]

However, in the absolute value control, the temperature deviation in the longitudinal direction (rolling direction) of the sheet material, or the temperature drops from the bite of the sheet material to the end of the sheet material,
When the temperature non-uniformity caused by the so-called thermal rundown occurs, the rolling load changes with the temperature non-uniformity, and as a result, it is necessary to prevent the thickness from fluctuating. In some cases, the control of the rolling-down position has become frequent, and the control amount has also increased.

[0006] In particular, in the case of rolling a thin plate material, the amount of control of the rolling position with respect to the plate thickness is relatively larger than in the case of rolling a thick plate material. The rolling reduction and the sheet crown ratio (sheet crown amount / sheet thickness) become non-uniform, and as a result, shape defects such as ear waves and medium waves frequently occur in the sheet material. In the localization control, since the rolling position is kept constant, even if a thin plate material is rolled, shape defects such as ear waves and medium waves may hardly occur.

However, as described above, in the localization control, it is difficult to set the rolling position with high accuracy, and if the setting accuracy is poor, it is likely that the thickness of the sheet material deviates from the target value at a considerably high rate. Therefore, when absolute value control is difficult to adopt, it is not simply possible to adopt localization control instead. The present invention has been made in view of the above circumstances, and regardless of the thickness of a sheet, a sheet thickness control method that enables rolling to a sheet having a target sheet thickness without causing a shape defect in the sheet. The purpose is to provide.

[0008]

According to the present invention, the following technical measures have been taken in order to achieve the above object. That is, in the sheet thickness control method according to the present invention, at the beginning when the sheet material is caught between the rolls, the sheet thickness is held at the target sheet thickness by performing absolute value control using a gauge meter method. Then, during the execution of the absolute value control and at an appropriate time until the plate material comes off from between the rolls, the control is switched from the absolute value control to the localization control for holding the roll down position at a predetermined position. is there.

In this case, since the execution time of the absolute value control is limited, unlike the case where the absolute value control is performed solely all the time (conventional example), the rolling position control becomes frequent or In addition, the control amount can be prevented from increasing. Therefore, it is possible to prevent the occurrence of shape defects such as ear waves and medium waves on the rolled sheet material.

In addition, unlike the case where the localization control is performed singly all the time (conventional example), the above-described absolute value control performed at the beginning of rolling sets the initial rolling-down position with extremely high accuracy. Therefore, it is possible to prevent the plate thickness of the plate material from deviating from the target value. The switching timing from the absolute value control to the localization control may be a time when the thickness of the plate material falls within a predetermined thickness range by the absolute value control, or a predetermined time has elapsed since the plate material was caught between the rolls. Can be time.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the rolling mill 1 that implements the sheet thickness control method according to the present invention lowers a backup roll 3 that presses a work roll 2 via a fluid pressure actuator or a reduction screw (not shown). Hydraulic or electric rolling device 4 for transmitting force, rolling load detecting means 5 for detecting the rolling load during rolling from the movement of backup roll 3 using a load cell or the like, and rolling position of work roll 2 to be lowered. A roll-down position detecting means 6 which can be appropriately detected by using a position sensor or the like from a movement amount of a fluid pressure actuator or a screw-down screw of the device 4,
A calculating means 8 for calculating the thickness of the plate 7 using a gauge meter method based on the detection data obtained from each of these detecting means 5 and 6 and for predeterminedly driving the screw-down device 4 based on the calculation result. It has a configuration provided.

And, in the sheet thickness control method according to the present invention,
As shown in the flowchart of FIG. 1, when the plate 7 has been engaged between the work rolls 2, the absolute value control is started first, and the plate thickness of the plate 7 is set within the range of the target plate thickness.
The rolling position of the work roll 2 is controlled to a predetermined position by the rolling device 4 (see steps 100 to 103). This absolute value control uses a gauge meter system as in the prior art, and the amount of deformation of the rolling mill 1 under a load obtained based on the rolling load detected by the rolling load detecting means 5 and the roll amount under no load. The calculation means 8 determines the roll gap of the work roll 2 during rolling from the gap, and the roll gap is used to calculate the sheet material 7 after rolling (outside).
Is calculated, and further based on this thickness, control is applied to the screw-down device 4 sequentially.

In this case, various corrections may be made by taking into account various disturbances which change every moment during rolling. Then, when it is confirmed by the absolute value control that the thickness of the plate material 7 is within the predetermined thickness range, the control is switched from the absolute value control to the localization control (steps 103 and 103). 104), and thereafter, until the plate material 7 comes off from between the work rolls 2, the localization control controls the pressing position of the work roll 2 by the pressing device 4 to a predetermined value (steps 104 to 104).
106).

Also in this localization control, the work roll 2 is set to a predetermined reduction position by the reduction device 4 as in the prior art, and this reduction position is kept constant during the rolling of the sheet material 7. After the plate material 7 has come off from between the work rolls 2, if the rolling mill 1 is reverse, the reverse is repeated until the number of reverses is satisfied, and the above steps 100 to 107 are repeated.
One cycle is completed when the number of reverse times is satisfied.

By performing the plate thickness control according to the present invention, it is possible to prevent the rolling position control from becoming frequent and the control amount from being increased. here,
Taking a case where a sheet material having a sheet thickness of 6 mm is rolled as an example, in comparison with the case where the absolute value control is performed singly all the time (FIG. 6), in the present invention, as shown in FIG. In the plate material, the shape defect such as the ear wave and the medium wave hardly occurred.

Also, in comparison with the case where the localization control is solely performed all the time (see FIG. 7), in the present invention, the localization is performed by the absolute value control performed at the beginning of rolling as shown in FIG. At the start of the control, the sheet thickness is within the tolerance, and the sheet thickness is within the tolerance, and the sheet thickness deviates from the target value because the sheet thickness is within the tolerance with the already set rolling position. Was almost nonexistent.

FIG. 4 shows the thickness control according to the present invention.
The flowchart of the embodiment shows that the switching time from the absolute value control to the localization control is a predetermined time after the time when the plate member 7 bites between the work rolls 2 (when the absolute value control is started). That is, in this embodiment, when the plate member 7 bites between the work rolls 2, the timer is started at the same time as the start of the absolute value control to start counting the time (see steps 200 to 202). When the predetermined time is counted by the timer, switching from the absolute value control to the localization control is performed (see steps 204 and 205).

The time set by the timer may be changed each time rolling is performed, based on experience in consideration of the material, external dimensions, rolling conditions, and the like of the plate 7. Other procedures are the same as those of the embodiment shown in FIG. In the embodiment shown in FIG. 4, since it is not necessary to determine whether the thickness of the sheet material during rolling falls within a predetermined thickness range by absolute value control, compared to the embodiment of FIG. 1,
It is not only easy to detect or judge the switching timing, but also there is an advantage that the absolute value control can be prevented from being excessively controlled.

Further, as shown in FIG. 5, by appropriately adjusting the set time of the timer, the thickness of the plate at the time of starting the localization control can be put in the middle range of the tolerance. There is an advantage that it is ensured that the thickness of the rolled sheet material is prevented from deviating from a target value. Incidentally, the present invention is not limited to the above embodiment.

For example, the type, detailed configuration, application, etc. of the rolling mill 1 are not limited at all, and thin rolling / thick rolling, cold rolling / hot rolling, reverse / continuous rolling, finish rolling -For rough rolling, etc., implementation changes can be made as appropriate.

[0021]

As is apparent from the above description, in the sheet thickness control method according to the present invention, the absolute value control is performed at the beginning when the sheet material is caught between the rolls, and thereafter, the control is switched to the localization control at an appropriate time. Therefore, unlike the case where absolute value control is performed singly from beginning to end, regardless of the thickness of the sheet, it is possible to prevent the occurrence of shape defects such as ear waves and medium waves in the sheet material after rolling. Unlike the case where the localization control is performed solely all the time, the thickness of the plate material can be prevented from deviating from the target value.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a sheet thickness control method according to the present invention.

FIG. 2 is a diagram schematically showing a rolling mill and its peripheral devices capable of performing a thickness control method according to the present invention.

FIG. 3 is a diagram showing a movement of a pressing position in a plate length direction and a plate thickness distribution in the method shown in FIG. 1;

FIG. 4 is a flowchart showing a sheet thickness control method according to another embodiment of the present invention, which is different from FIG.

5 is a diagram showing a movement of a pressing position in a plate length direction and a plate thickness distribution in the method shown in FIG. 4;

FIG. 6 is a diagram illustrating a movement of a rolling position in a plate length direction and a plate thickness distribution when absolute value control is performed singly from beginning to end.

FIG. 7 is a diagram showing the movement of the rolling position in the plate length direction and the plate thickness distribution when the localization control is solely performed from start to finish.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolling machine 2 Work roll 3 Backup roll 4 Rolling-down device 5 Rolling load detecting means 6 Rolling-down position detecting means 7 Plate material 8 Calculation means

Continued on the front page (72) Inventor Naotaka Kokugata 1 Kanazawacho, Kakogawa City, Hyogo Prefecture Kobe Steel, Ltd. Inside the Kakogawa Works (72) Inventor Shozo Sumino 1 Kanazawacho, Kakogawa City, Hyogo Prefecture Kobe Steel, Ltd. Inside Kakogawa Works (72) Inventor Mutsuro Shinmura 1 Kanazawacho, Kakogawa City, Hyogo Prefecture Kobe Steel Works Kakogawa Works (58) Fields surveyed (Int.Cl. ⁷ , DB name) B21B 37/00-37/78

Claims (3)

(57) [Claims] After the plate (7) has been engaged between the rolls (2), absolute value control using a gauge meter system is performed to maintain the plate thickness at the target plate thickness, and the plate (7) is rolled ( 2) A sheet thickness control method, wherein the absolute value control is switched to the localization control for holding the roll-down position of the roll (2) at a predetermined position at a predetermined time from the end to the end of the roll. 2. The switching timing from the absolute value control to the localization control is a time when the thickness of the plate material (7) falls within a predetermined thickness range by the absolute value control. The thickness control method described in the above. 3. The plate according to claim 1, wherein the switching timing from the absolute value control to the localization control is a point in time when a predetermined time has elapsed after the plate material (7) has been engaged between the rolls (2). Thickness control method.